Windrow Systems

Windrow systems are a traditional, low technology method for large-scale vermiculture activities. They consist of long beds placed directly on the ground with compostable organic material being applied to the surface and sometimes covered to reduce the incidence of pests.

Windrow systems are relatively inefficient as nutrients are lost through volatilisation and leaching and they require large areas of land. These systems also process organic materials relatively slowly taking between 6 and 18 months to complete processing (Edwards, 1995).

Windrow systems are most suitable to agricultural enterprises where large areas of land are available.

Materials that can be processed

A range of compostable organic materials can be processed in vermiculture units, however some form of pre-processing may be required. Pre-processing usually involves:

�� size reduction – to increase the

surface area for microorganisms

to attack;

Plate 2. Commercially available continuous flow vermiculture units.

Vermi-Converter 2000 – Vital Earth Company Worm Wigwam – EPM Inc. Eliminator 1200 – Pad Engineering

5 . . . . . . . . . . . .

�� mixing – to achieve a suitable structure, moisture content and nutrient balance; and

�� addition of a bulking agent – to improve structure, increase surface area and to absorb excess moisture.

Earthworms more readily process a mixture of compostable organic materials rather than monostreams of specific waste types, for example, just bakery waste (Recycled Organics Unit, 2000).

Common compostable organic materials produced by the C&I sector that are readily processed by vermiculture units include:

�� mixed fruit;

�� mixed vegetables; �� mixed food organics (mixed fruit

and vegetables, breads, meat/

poultry); and

�� mixed garden organics (lawn clippings, non-woody plant materials such as stems, leaves and twigs of various plant species).

The addition of a bulking agent, such as paper or cardboard, is very important when preparing compostable organic materials for processing in a vermiculture unit. Cardboard or paper are carbonaceous materials that absorb excess moisture, increase the porosity and structure of the material and increase the carbon to nitrogen (C:N) ratio.

The C:N ratio is the ratio of the weight of organic carbon to total nitrogen within the material. Some organic materials, such as meat and poultry, are rich in nitrogen. If these nitrogen-rich organic materials are processed in a vermiculture unit, carbon needs to be added to achieve a C:N ratio of 20 to 25 parts carbon to every one part nitrogen (C:N ratio of 20-25:1).

Carbon can be added to a

Plate 3. Shredded cardboard is a common source of bulking agent produced by the C&I sector.

vermiculture unit as shredded paper or cardboard. These high carbon materials are called bulking agents and are common packaging wastes in the C&I sector.

The addition of a bulking agent, such as paper or cardboard (Plate 3), not only increases the C:N ratio but improves the structure and porosity of the material. A bulking agent will also absorb excess moisture and result in a less dense material. All these factors produce a material that is more readily processed by the worm population.

The amendment of compostable organic materials with a bulking agent to increase the C:N ratio may result in the material becoming too dry. Worms need a moist environment, as previously discussed, and so the material that they consume needs to be moist but not too wet.

The final mixture of organic material amended with a bulking agent and water (if necessary) is called feedstock. Feedstock is the result of blending the different components to produce a suitable source of food for the worm population.

These factors are important for acceptance of the feedstock by the worm population. A number of feedstock recipes and the process of mixing a suitable feedstock will be covered in Information Sheet No. 4.

Materials that cannot be processed

Some compostable organic materials cannot be processed in a vermiculture unit.

Materials that are very high in nutrients, such as seafood and dairy products, are not recommended for vermiculture processing in any significant proportion. These materials can cause problems such as anaerobic (low oxygen) conditions that result in worm death.

6 . . . . . . . . . . . .

Microorganisms break down these Management of Overview of best practice

high nutrient materials very quickly vermiculture units guidelines for on-site resulting in rapid oxygen consumption. This can lead to health ^{Vermiculture units can be used to vermiculture technology} and safety issues such as odour ^{process a limited range of The Best Practice Guideline to} production and the attraction of pests ^{compostable organic materials into a Managing On-Site Vermiculture}

_{and vermin.} useful end product called vermicast. Technology series of information sheets provides an excellent

More information on materials that ^{However, effective vermiculture} introduction to the science of can and cannot be processed in ^{processing requires significant} vermiculture and the best practice vermiculture units can be found in ^{management of the unit to ensure} procedures for establishing and

_{Information Sheet No. 3.} reliable performance and to prevent _maintaining

a successful health and environmental issues from _{vermiculture unit.}

developing.

The process of achieving a successful Effective best practice management _{vermiculture organics management}

^{of vermiculture units requires a} system based on these best practice

^{dedicated approach to feedstock} guidelines is illustrated in Figure 4. preparation, monitoring regimes and site hygiene.

Figure 4. Overview of the Best Practice Guideline to Managing On-Site Vermiculture Technology Information Sheets.

7 . . . . . . . . . . . .

. . . . . . . . . . . .

Information Sheet No. 2 How much compostable material is produced?

Simplified waste audit

Quantifying the compostable material in

health and safety risks for staff (Plate 1).

This Information Sheet provides simplified methods that are more effective for quantifying the amount of organic material produced by your organisation.

Rather than conducting an unpleasant and unsafe “waste audit”, simply collect compostable organic materials (eg. food) separately in dedicated bins. The quantity of this compostable material can then be determined. The challenge is to keep general waste out of the “organics only” collection bins (and vice versa), but this is simpler than sorting through mixed garbage.

Unnecessary risks are identified and removed, allowing for simpler and more accurate estimations than typical waste auditing practices.

Implementation

When implementing a source separated collection system, the needs of operations staff must be

Plate 1. Conducting a waste audit of non-source separated waste material. Even if safety clothing is used, this may still involve unnecessary risks if sharps and/or other contaminants are present.

The ROU is the NSW centre for organic resource management, information, research & development, demonstration and training

addressed. If a new operational system is designed without adequate consultation, opportunities to create simpler and more efficient systems may be lost, contributing to problems that prejudice staff against the system.

Staff support is mandatory to maximise the diversion of organics from the waste stream and to minimise contamination levels in source separated material. Don’t be discouraged by the terminology – it’s simply encouraging colleagues to put their waste in the right bin, and making it convenient to do so.

Dissatisfaction with current practices and opportunities for reducing effort, can provide significant motivation for staff to support change. Aim to establish a system that better meets their expressed needs (eg. with respect to bin size, placement, ease of use etc.).

Generate awareness that discarding of waste in the correct bin contributes to environmental improvement and that putting waste in the wrong bin creates unnecessary waste and safety risks for colleagues.

When presenting a new waste management system to staff, confirm that the new system is a result of their expressed needs.

What materials are you looking for?

Prior to selecting an appropriate organics management system, it is important to identify the compostable materials generated by your organisation. Compostable organics may include (Plate 2):

�� Food organics

�� Garden organics

�� Wood and timber

�� Paper and cardboard

Plate 2. Materials you can use in your organics management system.

Food organics need bulking agents when used in organics management systems. They cannot be processed alone! Bulking agents include garden organics, wood and timber and paper and cardboard. Avoid using food organics high in oils and fats, as these may contribute to significant odour problems in your system.

Garden organics can be processed on their own or used as bulking agents with food organics. These materials have a relatively high carbon to nitrogen ratio, complementing the low carbon to nitrogen ratio of food organics.

Wood and timber can be used as bulking agents with food or garden organics. However, if these materials have been chemically treated, they should not be used in your organics management system. It is therefore important for you to know the composition (history) of your wood and timber and any associated health issues.

Paper and cardboard can be used as a bulking agent with food organics and/or garden organics. Due to the high carbon content and very low nitrogen content of paper and cardboard, these feedstock materials cannot be processed alone.

Definitions*

Compostable organics

Compostable organics is a generic term for all organic materials that are appropriate for collection and use as feedstocks for composting or in related biological treatment systems (e.g. anaerobic digestion). Compostable organics is defined by its material components: residual food organics; garden organics; wood and timber; biosolids, and agricultural organics.

Waste Audit

Determination of the quantities and qualities of individual components present in a waste stream.

Source separation

Physical sorting of the waste stream into its components at the point of generation.

Bulking agents

An ingredient in a mixture of composting raw materials included to improve the structure and porosity of the mix. Bulking agents are usually rigid and dry and often have large particles (for example, straw or wood chips). The terms “bulking agent” and “amendment” are often used interchangeably. See also composting amendment.

Carbon to nitrogen ratio

The ratio of the weight of organic carbon (C) to that of total nitrogen (N) in an organic material.

Continued page 5

2 . . . . . . . . . . . .

The assessment process Food organics

The identification of food organics generated by your business will be simpler, safer and more effective if the food organics are collected separately for a period of 2 weeks. This also provides an excellent opportunity for a short-term trial of a separate collection system.

Food organics include the following subcategories. These categories are useful in identifying suitable handling and processing technologies:

Material	Detail
Fruit and vegetable
material
Bread, pastries and	Including rice and
flours	corn flours
Meat and poultry
Fats and oils
Seafood	Including shellfish,
	excluding oyster
	shells
Food soiled paper	Hand towels, butter
products	wrap etc.
Biodegradeables	Cutlery, bags,
	polymers
Dairy	Solid and liquid
Recalcitrants	Large bones, oyster
	shell, coconut shells
	etc.

Use the following steps to identify the quantity and nature of your food organics:

1. Identify primary locations/ sources of generation of the food;
2. Consult with staff to identify current practice – what they like/dislike and existing inefficiencies;
3. Design separate organics collection system in consultation with staff employed at operation level to ensure that the system design meets their needs

A source separated organics collection system must meet the needs of operational staff within your

3 . . .

organisation. If the new system is �� placed next to each garbage/ designed without adequate waste bin; and consultation, problems may arise that may discourage staff from disposing ^{�� located so that the same amount} of materials correctly into “food ^{of effort is required to place}

_{only” bins.} material in the “food only” bin

or the garbage bin (if one With staff support, the diversion of requires a lid to be removed, or organics from the waste stream will is a little further away the other be maximised (maximising may receive both waste streams). environmental benefits and cost savings), and contamination rates of ^{Promote the commencement of the} _{the organics stream minimised} trial period. Have someone from

(minimising unnecessary effort and ^{kitchen management or elsewhere} _{safety risks).} communicate to all staff the purpose, timeframe and process of quantifying Aim to establish a system that meets the amount of compostable materials

the expressed needs of staff (eg. with produced. respect to bin size, placement, ease of _{use etc.)} Let staff know they will play a

valuable role in ensuring the success Confirm with operational staff that of the project. Also engage them in the new system will meet their needs. the process to identify improvements

in the system and to make it more

4. Install source separate collection

consistent and efficient for use.

bins with appropriate signage etc

5. Collect organics generated over Install the new source separate _{a two-week period} collection bins. Make sure that all bins are placed at the same time to The waste audit results will inform avoid confusion, organics ‘leakage’ selection of a processing technology to the waste stream or contamination that is capable of meeting your

of organics collected. Where organisations needs. possible, ensure that “organics only” _{bins are:} In order to obtain reliable and

accurate estimates of the volume and �� a standard size and distinct composition of your organisation’s colour with consistent clear organics stream, it is important to signage; sample organics over a period of at least two weeks. In addition, it may ^{�� readily recognisable from} be necessary to spend one week ^{garbage bins;} preparing for the audit – ironing out

any bugs in the process. You should ^{�� obviously marked/labelled;} record audit information on Form 1 _{�� appropriate size, location and} (attached to this Information Sheet).

number;

. . . . . . . . .

The steps involved are summarised below:

�� Collect the filled separated “food organics only” bins on a daily basis);

�� Remove waste contaminants (plastics, drink containers etc.) – document type and source of contamination;

�� Estimate seasonal variation from 7. Contamination

�� Tip contents of bins containing _{business records, staff numbers} ^{only small amounts of material} etc. to establish peak volumes of ^{Contaminants in food organics} together to minimise the number _{material that would be expected} comprise anything not compostable, of bins being weighed; _{during busy periods.} including:

^{�� Weigh the filled bins on a} Data on seasonal fluctuations in ^{�� individual portion wrappers platform scale;} catering, generation of garden ^{(plastic or foil);} _{�� Record the weight on the data} organics etc. can be obtained from

_{recording sheet supplied, business records and consultation} �� plastic bags, cling wrap films

attached to this Information ^{with operational staff. and plastic cutlery;}

^Sheet; 6. Tools and materials required ^{�� glass;}

�� stainless steel cutlery, foil and

^{�� Use the bottom of a bucket to} The materials required to determine

other metals;

^{compress the food organics} the amount and composition of the

firmly into each bin so that the _{food organics are listed below:} contents are reasonably well ^{�� ceramics, and}

^{packed; �� Platform scales} �� drink containers.

�� Estimate total food organics �� Data recording sheets (attached)

Contamination increases the

volume from the size of the bin

workload and labour costs of an

and the amount of material in it �� Tubs for estimating composition _{organics management system. In}

^{(compressing material avoids} addition, contaminants make work counting low density materials ^{�� Food waste collection bins} _{very unpleasant (removal of} (eg. cabbage/lettuce leaves) as a _{�� Stickers for identifying bins}

contaminants) and create safety ^{full bin);} hazards for staff (glass and metals, �� Tongs for removing _{see Plate 3).}

�� Tip bin contents into shallow _contaminants tubs for visual (percentage)

8. Monitor solid waste stream to ^{estimates of organics �� Gloves (heavy duty kitchen} identify any organics ‘leakage’;

composition; _gloves)

Improve organics diversion success

�� Combine your contaminants into _{�� Scrubbing brush and access to through education. Remember to}

^{one bin and weigh them; water for cleaning out bins} address any problems in system

�� Empty tubs into a garbage skip _{�� Educational posters for staff} ^{implementation immediately. All} _{or bin for collection;} staff working at operational level room

should understand clearly how the �� Wash out “food organics only”

�� Presentation materials for staff ^{separation system works, and should} bins and return to kitchen staff; _meeting have had the opportunity to contribute to system design to ensure �� At the end of each week, Supplier information and prices for it is convenient and efficient for their calculate the total weight of the _{this equipment is contained in} use. food organics material and the _{Appendix No. 1.} average volume of each type of There should be no general waste material identified; contamination of the collected food

4 . . . . . . . . . . . .

Plate 3. Contaminants such as glass may be encountered during waste audits – especially if a source separation system has not been developed.

organics and no leakage of food organics into the general waste. If this does occur, rectify the problem by communicating directly with those responsible and encouraging them to help achieve successful outcomes.

1. Improve organics diversion rate and maintain through consultation and education.
2. Bin hygiene

Bins must be cleaned and maintained to control odours. Water and a long handled scrubbing brush can be used to achieve this. In some instances, a small amount of detergent may also be required.

11. Bin size

Consider bin size and how bins need to be handled in your system. Food organics can be very dense and heavy, ranging in weight from 0.4 kg to over 0.8 kg per litre. At the upper end of this scale, a 120 litre bin could weigh over 90 kg, which is both unsafe and well in excess of the maximum capacity of the bin.

Given the nature of food organics, 80 litre wheelie bins are the most appropriate size available for food organics collection. Larger bin sizes can be too heavy (when full) for collecting dense food material.

Continued from page2

Waste Stream

Flow of materials from a point of generation to ultimate disposal.

Contamination

Contaminants within this context include physical inorganic materials (metals, glass etc.), non-biodegradable organic materials (plastics), chemical compounds and/or biological agents that can have a detrimental impact on the quality of any recycled organic products manufactured from source separated compostable organic materials.

Feedstock

Organic materials used for composting or related biological treatment systems. Different feedstocks have different nutrient concentrations, moisture, structure and contamination levels (physical, chemical and biological).

* Recycled Organics Unit (2001a).

12. What happens now?

After the two-week sampling period, you should have a clear understanding of the volume and composition of food organics generated within your organisation. You should also have estimates of variation across the annual business cycle. This information (in combination with other factors) can be used to identify a system that best suits your requirements.

5 . . . . . . . . . . . .

Identifying your food organics materials

Empty bin contents Collect the separate

into shallow tubs for food organics bins on

visual (%) estimation a daily basis of food organics composition.

Remove waste contaminants (glass,

Combine your

plastics, drink

contaminants into

containers etc.),

one bin and weigh

document type and

them.

source of contamination.

Minimise the number of bins you use

Empty tubs into

(combine contents of

skip/bin for

bins that only have

collection.

small amounts of material in them).

Compress the organics into each

Wash out bins and bin so that the

return to kitchen contents are

staff. Bins must be reasonably well

cleaned and packed. You can

maintained to control use the bottom of a

odours. bucket to do this.

Calculate the total

weight of the food

organics material Weigh the filled bins

and the average on a scale. Record

volume of each type the total volume and

of material identified. weight on data recording sheets.

Estimate seasonal

variation from

business records.

. . . . . . . . . . . .

Plate 4. Quantifying the amount and type of garden organics produced by your^{Garden organics} organisation may be difficult, but it is still important if you want to use this material _{Garden organics material can form a} in your new organics management system.

substantial proportion of the solid waste stream, particularly during summer and after storm events.

In some instances quantifying the garden organics produced by your organisation may be difficult. Nevertheless, you should try to characterise this component of your waste stream.

Garden organics materials include the following subcategories, which are useful in identifying suitable handling and processing technology:

Material	Detail
Putrescible	grass clippings
garden
organics
Non-woody	leaves, sapwood,
garden organics;	prunings (<10 mm ∅)
Woody garden	branches, twigs
organics;	(>10 mm ∅)
Trees and
limbs;
Stumps and
rootballs.

Use the following steps to quantify and identify the nature of your garden organics (Plate 4):

1. Consult with relevant staff

Consultation with relevant staff members is essential to determine the amount of garden organics material produced. Identify materials present and the quantities of materials generated. If possible, ask gardening staff to fill out Form 2 for a two week period to characterise the garden organics generated.

If gardening staff cannot give you accurate estimations of garden organics generated, it will still be useful to have garden staff provide a guesstimate of the amount of each material produced.

2. The audit process

8 . . .

Over a two week period, encourage �� Make notes of any storm events gardening staff to record the volume etc. that may have influenced the and composition of the garden amount of material organics generated. In addition, generated/collected during the identify current practices with your audit period. garden organics – are they stock _{piled, mulched, burnt, dumped in a} Note: If your garden organics have _{skip etc.?} been size reduced/shredded prior to

auditing, the volume of material will Use the following steps to determine be significantly reduced. the amount and type of garden

_{organics produced by your} 3. Exclude materials from the audit

^{organisation:} If materials such as lawn clippings _{�� Have gardening staff count the} are usually left uncollected on lawn _{number of grass catchers,} areas, then do not count this material _{trailers, trucks, and/or skips} in the audit. Leaving this material on _{filled with garden organics each} the ground is the optimal choice – not _day. requiring further effort or management. The goal of the �� Determine the volume of each organics management system is to type of storage medium. improve poor practice, not to change best practice where it already occurs.

�� To determine the overall volume of materials generated on a daily 4. Check the audit results basis, multiply the number of

_{times a container is filled by its} After the two week period, it will be _volume. useful to feed data back to gardening staff and confirm the audit results.

�� Estimate the total volume of Determine if the results are typical or material generated on a weekly atypical of what is usually produced. basis by adding the daily totals

_together. Identify the effects of season or the impact of other events such as storms

�� Try to characterise the on the amount and type of material proportion of different garden produced. organics generated on a daily/weekly basis.

. . . . . . . . .

Form 2. Auditing your garden organics

9 . . . . . . . . . . . .

Wood and timber

Wood and timber materials can be a substantial proportion of the solid waste stream for some types of enterprises. These materials have a very high carbon to nitrogen ratio, complementing the low carbon to nitrogen ratio of food organics.

Wood and timber organics include the following subcategories, which are useful in identifying suitable handling and processing technologies:

Material

off-cuts crates pallets and packaging saw dust timber shavings

For use in your organics management system, you should consider only saw dust and/or timber shavings, and only if the material is from wood that exposes staff to unnecessary risks. is not painted or treated. The use of other wood and timber materials may ^{The audit process} create more problems than benefits. _{As with garden organics and food}

Avoid chemically treated or composite ^{organics, collect residual wood and} wood products timber materials over a two week

period.

Avoid using chemically treated wood and composite wood materials, as _{�� Remove any contaminants} they contain dangerous chemical compounds (eg. formaldehyde, �� Place the residuals in easy to creosote, etc.) that may pose potential weigh containers and weigh on a health risks to your staff. daily or weekly basis (depending

on quantity produced)

Use wood materials that are already

^{in a form to be processed} �� Identify type and source of For OH&S reasons and also for ease contamination (if any) of management, it is best to use wood and timber materials that are already ^{�� Dispose of material, as is usual} in a form to be processed (saw dust ^practice

^{and shavings).} �� Clean containers (if necessary)

Size reduction of materials adds

�� At the end of the two-week considerable time to the processing _{period calculate the quantity and} of the wood and timber, requires _{composition of material} expensive equipment and also _{generated using Form 3.}

10 . . . . . . . . . . . .

Paper and cardboard

Paper and cardboard materials can be a substantial portion of the solid waste stream for many enterprises. Whilst not wanting to impact on effective paper recycling, some of this material may be useful to the organics management system. Paper and cardboard has a very high carbon to nitrogen ratio – complementing the very low carbon to nitrogen ratio of food organics.

If you have not established a paper recycling system, the guidelines are provided in “Office Paper, Recycle it” NSW EPA (1990).

Use pre-shredded paper/cardboard

For ease of management and to facilitate the organics management system, only use non-waxed paper and cardboard. The size reduction of paper and cardboard can be difficult and time consuming without expensive equipment. So be sure to identify shredded paper and cardboard. It will be much easier to use in your organics processing system.

The audit process

As with other materials, monitor the amount of paper produced by your organisation over a two-week period. Quantify volumes generated on a daily/weekly basis, identifying contaminant levels and the effects of special events etc. on volumes generated. To quantify materials produced, your organisation should:

�� Collect paper in easy to weigh containers or as per existing system;

�� Weigh paper on a daily/weekly basis using platform scales as identified previously;

�� Determine the volume of paper generated from the size of the containers.

�� Identify type and source of contamination (if any);

�� “Dispose” of or recycle paper through regular practice;

�� At the end of the 2 week period, calculate the amount of material generated weekly.

11 . . . . . . . . . . . .

If you don’t have a paper recycling system, provide a copy of the previous page and Form 4 to someone else who is interested in developing paper recycling in your organisation.

Estimating variation across the annual cycle

maximum expected volumes. If the “audit” is conducted during a quiet period – use business records (eg. purchasing, reservations, bookings etc.) and consult with operational staff to estimate maximum expected volumes.

Document maximum expected organisation. The selection of an appropriate organics management system can be made according to this identification of specific compostable materials produced.

Vermiculture units are suitable for processing the following compostable organic materials:

If large quantities of compostable materials that do not fall into these categories are produced by your organisation, an alternative organics management system, for example composting, should be implemented that more readily processes these types of materials.

More information on alternative organics management systems, such as composting, can be found in On-Site Composting: Technology Options and Process Control Strategies (Recycled Organics Unit, 2001b) or visit http://www.recyledorganics.com.

Information Sheet No. 3 Can vermiculture work for you?

=

Vermiculture processing Food organics suitable for vermiculture processing

The use of vermiculture for

The ROU is the NSW centre for organic resource management, information, research & development, demonstration and training

The trials performed by the Recycled Organics Unit also found that food organics can be processed using vermiculture, however, materials need to be prepared into a suitable feedstock.

The definition for food organics contains the following subcategories:

Material	Detail
Fruit and
vegetables
Bread, pastries	Including rice and
and flours	corn flours
Meat and poultry
Fats and oils
Seafood	Including shellfish,
	excluding oyster shells
Food soiled paper	Hand towels,
products	butter wrap etc.
Biodegradeables	Cutlery, bags,
	polymers
Dairy	Solid and liquid
Recalcitrants	Large bones,
	oyster shell,
	coconut shells etc.

Of these categories, the trials performed by the Recycled Organics Unit indicated that seafood, dairy, and monostreams of bread, pastries and flours and meat are not suited to vermiculture processing in any significant quantity.

Also, previous qualitative experience has indicated that as higher proportions of bread, meat and dairy are combined with fruit and vegetables in a mixed food organics feedstock, the capacity of vermiculture technology to process this material, is significantly decreased (Kater, 1998; Recycled Organics Unit, 2000).

As a result of these studies, the Recycled Organics Unit recommends that on-site vermiculture technology is suitable for the following categories of food organics material: �� only fruit and vegetables; or

�� predominantly fruit and vegetables with a relatively small proportion of bread and meat/poultry.

Although it may be possible for vermiculture to process a wider range of food materials, the risk of problems occurring and the management skill and effort required to sustain the process means that vermiculture processing is not appropriate for C&I sector on-site applications.

Choosing a suitable processing technology

Performing an audit of all compostable organic materials produced on-site will allow an identification of the types and quantities of compostable materials produced by your organisation.

If large quantities of fruits and vegetables were identified in the audit, vermiculture technology may be a suitable option for processing this compostable material. However, if materials that are difficult to process using vermiculture make up a significant proportion of your total material, a different form of processing technology, for example on-site composting or a source separated collection system for centralised processing, will be more suitable.

More information on other forms of processing technology can be found in “Implementing an Organics Management System: A planning and implementation workbook for the commercial and industrial sector” (Recycled Organics Unit, 2001a) or from http://www.recycledorganics.com.

Definitions*

Compostable organics

Compostable organics is a generic term for all organic materials that are appropriate for collection and use as feedstocks for composting or in related biological treatment systems (e.g. anaerobic digestion). Compostable organics is defined by its material components: residual food organics; garden organics; wood and timber; biosolids, and agricultural organics.

Food organics

The Food Organics material description is defined by its component materials, which include: fruit and vegetable material; meat and poultry; fats and oils, seafood (including shellfish, excluding oyster shells); recalcitrants (large bones >15mm diameter, oyster shells, coconut shells etc.); dairy (solid and liquid); bread, pastries and flours (including rice and corn flours); food soiled paper products (hand towels, butter wrap etc.); and biodegradeables (cutlery, bags, polymers). Such materials may be derived from domestic or commercial and industrial sources. The definition does not include grease trap waste. Food organics is one of the primary components of the compostable organics stream.

Composting

The process whereby organic materials are pasteurised and microbially transferred under aerobic and thermophilic conditions for a period of not less than six weeks. By definition, it is a process that must by carried out under controlled conditions yielding mature products that do not contain any weed seeds or pathogens.

*Recycled Organics Unit, (2001b)

2 . . . . . . . . . . . .

. . . . . . . . . . . .

required

Selection of a vermiculture unit

Selection of the type and size of vermiculture unit required will vary from site to site depending on a number of factors. These factors include:

�� type of materials to be processed;

�� cost;

�� purpose of the vermiculture unit;

�� availability of complementary materials;

�� vermiculture processing capacity for the organic material; and

�� availability of space and other site specific constraints.

In order to determine what size vermiculture unit is required a ‘waste’ audit needs to be conducted to determine the quantity and type of

Information Sheet No. 4

Guide to feedstock preparation anddetermining what size vermiculture unit is

materials you produce. This auditing process has been detailed in Information Sheet No. 2.

Establishing a source separated collection system is essential for the collection of compostable organic material for processing in a vermiculture unit. This process is also detailed in Information Sheet No. 2.

Following this, you need to evaluate whether vermiculture technology is suited to processing the materials that are produced by your organisation. This process is detailed in Information No. 3.

Plate 1. Feedstock for successful vermiculture processing requires a combination of size reduced organic materials and a carbonaceous bulking agent.

The ROU is the NSW centre for organic resource management, information, research & development, demonstration and training

Feedstock composition

The volume of compostable material a vermiculture unit can process (see processing capacity) will vary depending on the type of material being processed, the size of the unit, the amount of worms housed in the unit, and management of the unit.

Vermiculture units more readily treat a mixture of organic materials than ‘monostreams’ of a single material.

Preparing material for processing

Organic materials to be processed by a vermiculture unit should be size reduced to enable effective processing by the worm population (Plates 2 and 3).

The addition of a bulking agent is required to form a feedstock that will support problem free processing.

Plate 2. Fruit and vegetables prior to size reduction using a bucket and spade method.

Plate 4 shows a final feedstock of size reduced fruit and vegetables blended with a cardboard bulking agent.

The importance of a bulking agent

A bulking agent is a carbonaceous material, such as paper or cardboard, that is added to a feedstock to increase the carbon to nitrogen (C:N) ratio and to help achieve a suitable moisture level, thereby improving the structure and porosity of the feedstock.

An ideal C:N ratio of a feedstock for vermiculture processing is 20 to 25 parts carbon to 1 part nitrogen (20-25:1). Maintaining this C:N ratio is especially important when processing organic materials that are high in nitrogen such as meats and poultry.

If the C:N ratio is not ideal, these high nutrient materials will decompose rapidly and problems such as odour development and pest attraction may occur.

The addition of a bulking agent also increases the structure and porosity of a feedstock. These factors result in a more suitable environment for the worms and hence processing will be more effective.

Cardboard and office paper are common residual materials of the C&I sector and these materials can provide an excellent on-site source of bulking agent if they can be size reduced.

Bulking agents need to be size reduced and thoroughly mixed with the organic materials to create a suitable feedstock (Plate 4).

In some instances achieving the desired C:N ratio and moisture content may require the addition of water. Feedstocks containing materials such as breads, for example, tend to be quite dry yet are high in nitrogen. A moisture content of approximately 80% is ideal for a vermiculture feedstock mixture.

A number of generic recipes (by weight and by volume) for feedstock mixtures comprising organic materials commonly produced by C&I sector organisations are shown in Tables 1 and 2.

Plate 4. Blended feedstock of mixed fruit and vegetable and cardboard bulking agent ready to be processed by a vermiculture unit.

Plate 3. Fruit and vegetables after size reduction using a bucket and spade method. Note the very watery texture. Shredded cardboard can be added to soak up the excess water.

2 . . . . . . . . . . . .

Table 1. Feedstock recipe guide (by weight) for compostable organics material and cardboard bulking agent. Feedstock type1 Maximum sustainable processing capacity (kg/m2/wk) Components3 Composition by weight (%) Composition by weight (kg) Ratio of organics to bulking agent Fruit 41.0 6.8 Vegetables 41.0 6.8 Cardboard 18.0 2.9 Fruit and/or vegetables + cardboard 16.5 Total: 100.0 16.5 4.7:1 Fruit 22.0 2.2 Vegetables 20.0 2.0 Bread 3.0 0.3 Meat/poultry 9.0 0.9 Cardboard 21.0 2.1 Water 25.0 2.5 Mixed food organics + cardboard 10.0 Total: 100.0 10.0 2.6:1
Lawn clippings and non-woody plant materials 70.0 4.0 Water 30.0 1.8 Garden organics 5.8 Total 100.0 5.8 No bulking agent required
Pre-consumer fruits and vegetables 51.0 6.8 Post-consumer plate scrapings (mixed food organics) 30.0 4.0 Cardboard 19.0 2.5 Miscellaneous food organics + cardboard (eg. Café food scraps) 13.3 Total: 100.0 13.3 4.3:1

¹ Note that this data is a result of extensive applied trials that have shown such feedstock mixtures can support sustained vermiculture processing

without resulting in negative environmental impacts or system failure (Recycled Organics Unit, 2000). ² Processing capacity is the maximum amount (kg) of compostable organics that can be added to a vermiculture unit per week without causing system failure. System failure is evident when the processing technology produces problematic environmental emissions and/or declines in processing efficiency and/or produces a product of unacceptable quality (Recycled Organics Unit, 2000b). Overfeeding of a vermiculture unit will exceed the maximum processing capacity resulting in problems and management requirements.

³ Shredded paper is a common C&I sector waste material that can be used as a bulking agent when combined with compostable organics material. However, no data is available at present on appropriate mixing rations to enable processing in vermiculture units. Experimentation with blending ratios is recommended in order to use shredded paper as a bulking agent.

. . . . . . . . . . . .

Table 2. Feedstock recipe guide (by volume) for compostable organics material and cardboard bulking agent. Feedstock type1 Maximum sustainable processing capacity2 (L/m2/wk) Components3 Composition by volume4 (%) Composition by volume4 (L) Ratio of organics to bulking agent Fruit 34.0 8.0 Vegetables 35.0 8.5 Cardboard 31.0 7.5 Fruit and/or vegetables + cardboard 24.0 Total: 100.0 24.0 2.2:1 Fruit 14.0 2.5 Vegetables 14.0 2.5 Bread 5.0 1.0 Meat/poultry 5.0 0.9 Cardboard 48.0 8.6 Water 14.0 2.5 Mixed food organics + cardboard 18.0 Total: 100.0 18.0 0.8:1
Lawn clippings and non-woody plant materials 94.0 28.3 Water 6.0 1.7 Garden organics 30.0 Total 100.0 30.0 No bulking agent required
Pre-consumer fruits and vegetables 38.0 8.3 Post-consumer plate scrapings (mixed food organics) 16.0 3.4 Cardboard 46.0 9.9 Miscellaneous food organics + cardboard (eg. Café food scraps) 21.6 Total: 100.0 21.6 1.2:1

¹ Note that this data is a result of extensive applied trials that have shown such feedstock mixtures can support sustained vermiculture processing

without resulting in negative environmental impacts or system failure (Recycled Organics Unit, 2000). ² Processing capacity is the maximum amount (kg) of compostable organics that can be added to a vermiculture unit per week without causing system failure. System failure is evident when the processing technology produces problematic environmental emissions and/or declines in processing efficiency and/or produces a product of unacceptable quality. (Recycled Organics Unit, 2000b). Overfeeding of a vermiculture unit will exceed the maximum processing capacity resulting in problems and management requirements.

³ Shredded paper is a common C&I sector waste material that can be used as a bulking agent when combined with compostable organics material. However, no data is available at present on appropriate mixing rations to enable processing in vermiculture units. Experimentation with blending ratios is recommended in order to use shredded paper as a bulking agent.

⁴ Note that all volumes are for size reduced feedstock components.

. . . . . . . . . . . .

Mixing a suitable feedstock

Preparing a suitable feedstock for processing in a vermiculture unit is a crucial step in ensuring a healthy environment for the worm population.

Many failures of vermiculture units can be attributed to the addition of unsuitable feedstocks or excessive quantities of feedstock. Problems that can result from an unsuitable feedstock include:

�� feedstock too moist – resulting in anaerobic (low oxygen) conditions;

�� feedstock too dry – not suitable for worm movement and habitation;

�� feedstock containing components that cannot be readily processed by the vermiculture unit – such as seafood or dairy material;

�� feedstock loading rate too high – too much feedstock applied to the unit resulting in feedstock build up, anaerobic (low oxygen) conditions and worm death;

�� feedstock particles too large – size reduction is necessary for effective processing (eg. particles >50 mm should be size reduced).

Some generic vermiculture feedstock recipes have been given in Tables 1 and 2. The steps for preparing a suitable feedstock are given below and will follow the recipe for a mixed fruit and vegetable feedstock (by volume).

1. Feedstock should be prepared daily. Storage of feedstock and unprocessed food organics components should be avoided as this can result in odour production and pest attraction.
2. Wear gloves and an apron whilst handling materials and preparing feedstock.
3. Collect source separated mixed fruits and vegetables from collection point (eg. kitchen).
4. Place the raw size reduced food organics (Plate 2) in a tub or tray suitable for mixing.
5. Size reduce by chopping with a spade (Plate 3).
6. Estimate the volume of raw organics material – using buckets of known volume is

helpful for this task, or mark the inside of tub for different volumes.

1. Determine the quantity of bulking agent required (see Table 2) to obtain a suitable C:N ratio, moisture content and structure (Plate 5).
2. Combine the raw organics material and bulking agent thoroughly. A fork or shovel is useful for this task (Plate 6).
3. Check the moisture content is suitable by performing the ‘fist test’ (also known as ‘squeeze test’).

Take a hand dull of feedstock and squeeze firmly (Plate 7). Some moisture should be released between the fingers however the feedstock should not be saturated.

If the feedstock is too moist, it may be beneficial to allow the bulking agent in the feedstock to absorb moisture for 10 minutes and then checking the moisture content again. The bulking agent may absorb more of the moisture over time. If the feedstock is still too moist, more bulking agent

Plate		5.	Blending			of	a	Plate	6.		Use a fork or			Plate 7. ‘Fist test’ used	Plate 8. Final feedstock of
cardboard bulking agent with								shovel		to		blending	the	to determine the correct	mixed fruit and vegetables
raw	fruit			and	vegetable			feedstock components.						moisture content for the	blended with a cardboard
feedstock to soak up excess														feedstock.	bulking agent.
water and to raise the C:N
ratio to an optimum level.

5 . . . . . . . . . . . .

should be added. This will increase the C:N ratio, which is not ideal, but may be the balance of variables possible.

If the feedstock is too dry (which may be the case for feedstocks made from dry materials such as bread), water should be added and the moisture content checked using the ‘fist test’.

10. The final feedstock should have a suitable moisture content, a good structure and a C:N ratio of between 20-25:1 (Plate 8).

Feedstocks should be applied immediately to a vermiculture unit, and then the tools used and site should be cleaned, ensuring no food material is left exposed to the environment as this can result in odour generation and pest attraction.

Maximum processing capacity

The processing capacity of vermiculture technology refers to the maximum amount of organic material that can be added to a vermiculture unit per unit time (eg. week) without causing system failure.

Vermiculture units have a limit to the amount of organic materials that can be processed over time.

If the maximum processing capacity is exceeded, problems can arise such as anaerobic (low oxygen) conditions, worm death, odour production, pest attraction and ultimate system failure.

The maximum processing capacity of a vermiculture unit is dependent on the type of materials being fed to it (feedstock composition) as worms process different organic materials at different rates.

As discussed in Information Sheet No. 3, the installation of a

6 . . .

vermiculture unit will only be successful if the appropriate compostable material is processed in the unit at an appropriate loading rate.

Trials performed by the Recycled Organics Unit found that fruit and vegetables are the most appropriate organic materials for vermiculture processing

Seafood, dairy, and monostreams of bread and meat are not suited to on-site vermiculture processing in any significant quantity.

Also, previous qualitative experience has indicated that as higher proportions of bread, meat and dairy are combined with fruit and vegetables in a mixed food organics feedstock, the capacity of vermiculture technology to process this material, is significantly decreased (Kater, 1998; Recycled Organics Unit, 2000).

As a result of these studies, the Recycled Organics Unit recommends that on-site vermiculture technology is suitable for the following categories of food organics material (Plate 9):

�� only fruit and vegetables; or

�� predominantly fruit and vegetables with a relatively small proportion of bread and meat/poultry.

Although it may be possible for a vermiculture unit to process a wider range of food materials, the risk of problems occurring and the management skill and effort required to sustain the process means that vermiculture processing is not appropriate for C&I sector on-site applications.

The maximum processing capacity of a vermiculture unit in relation to two feedstocks with varying compositions is shown in Figure 1, based on research performed by the Recycled Organics Unit (see Appendix No. 4).

Note that a mixed food organics and cardboard feedstock, containing meat and bread material, requires a higher proportion of bulking agent (due to the higher nitrogen content in meat and bread) and can be processed by a vermiculture unit at a lower application rate than the fruit and vegetable and cardboard feedstock.

The maximum processing capacity is expressed as the volume of feedstock applied per square metre of bedding surface per week (given appropriate siting, worm population and management).

Plate 9. Food organics suitable for processing in vermiculture units include only fruit and vegetables or predominantly fruit and vegetables with relatively small proportions of bread and meat/poultry.

. . . . . . . . .

What size vermiculture unit do I require?

The size of the vermiculture unit required for on-site processing of compostable organic materials will be calculated from the results of an audit of waste produced on-site as previously discussed. The size the process is likely to fail.

The processing capacity of a number of example feedstocks is shown in Table 3. This table will aid in calculating the surface area (m²) that is required to process the volumes of organic materials produced on-site.

Figure 2. The size of a vermiculture unit required to adequately process the amount of organic material produced onsite is dependent on the size of the surface feeding area. The surface feeding area for an example vermiculture unit is shown below. This unit has a surface feeding area of

0.53 m².

calculated is actually the number of square metres (m²) of surface feeding area that is required (Figure 2).

The size/number of vermiculture units selected must be large enough to effectively process the volumes of organic materials produced on-site. If your vermiculture unit is too small, This can be done by following these steps:

1. The type and volume of food organic material is found by the audit (Information Sheet No. 2).
2. Volume of feedstock – calculate the volume of feedstock (raw size reduced food material +

Minimum feeding area (1 m²) Minimum feeding area (1 m²)

7 . . . . . . . . . . . .

Table 3. Processing capacities and estimated surface feeding area required for suggested feedstocks Feedstock Composition Maximum processing capacity of blended feedstock (L/m2/wk)* Volume of feedstock from your site after blending with bulking agent where appropriate (L/wk) Calculated surface feeding area of vermiculture unit required (m2) Mixed fruit and/or vegetables �� Mixed fruit �� Mixed vegetables �� Bulking agent 24 a Mixed food organics �� Mixed fruit �� Mixed vegetables �� Meat/poultry �� Bread �� Bulking agent 18 b Garden organics �� Lawn clippings �� Garden organics 30 c Miscellaneous organics (eg. Café food scraps) �� Pre-consumer mixed fruits and vegetables �� Post consumer plate scrapings (mixed food organics) �� Bulking agent 24 18 a b 2#2 mm 24 x a ==2#2 mm 30 x c ==2#2 mm 18 x b ==2# 22 m m 18 m 24 x ba =+=

* Based on maximum loading rates calculated by the Recycled Organics Unit (2000). ^# Where x is the calculated surface feeding area required based on the amount of feedstock to be processed on-site.

bulking agent) to be processed each week (and the amount of bulking agent necessary to make the process work). This can be calculated using Table 1 or 2.

1. Feeding area required – calculate the surface feeding area required (m²) according to the equation in Table 3 and the feedstock type (see Figure 2).
2. Use this calculated surface feeding area requirement to select one or more vermiculture unit/s that will provide the required surface feeding area.

Stocking the unit with worms

The types of worms used in vermiculture units are not worms that are commonly found in gardens.

Worms used in vermiculture units tend to process larger amounts of organic material, reproduce in confined environments (such as vermiculture units), and cope well with disturbances (such as feeding and maintenance procedures) when compared with other common species (Appelhof, 1997).

Eisenia fetida (Tiger worm) is the worm most commonly used in vermiculture units in warm climates (Plate 10). These worms process relatively large amounts of organic materials and naturally occur in manure, compost and decaying leaves. These worms also reproduce quickly, have a relatively wide tolerance to temperatures and moisture (for worms), and are readily handled (Edwards, 1988).

Other names for Eisenia fetida include the ‘Tiger worm’, ‘Redworm’ and ‘Red wiggler’.

When establishing a vermiculture unit, the correct type of worm needs to be incorporated at a sufficient quantity to process the organic materials produced on-site.

Depending on the feedstock types, a worm application rate of between 10 and 18 kg per metre of bedding

8 . . . . . . . . . . . .

surface (10 – 18 kg/m²) is recommended as a sufficient rate to quickly establish maximum processing capacity (Recycled Organics Unit, 2000).

When establishing a vermiculture unit, it is important to provide a suitable environment for the worm population. The unit must be filled with bedding material to provide a safe and desirable habitat for the worm population.

The most suitable bedding material is mature vermicast that is composed of organic materials already processed by a worm population. Approximately 30 cm of mature vermicast will provide an excellent habitat for the worms. This amount of bedding will result in a more established environment ultimately increasing the processing capacity of the unit.

Introducing the worm stock to a vermiculture unit should be performed in the morning. This will ensure the worm population does not exit the unit, as daylight will deter the worms from escaping. Alternatively, a bright light can be used to encourage the worm stock to burrow into the new environment.

Sprinkle the worm stock carefully over the surface of the vermiculture unit. The worms will quickly burrow into the bedding material. Ensure the bedding material is moist but not too

Plate 10. Tiger worms (Eisenia foetida) are a common worm species used in vermiculture units.

wet. The ‘fist test’ should be used to ensure the moisture content of the bedding material is suitable moisture for the worm stock. This procedure is described in detail in Information Sheet No. 6.

A period of acclimatisation is necessary for the worm stock when introduced to this new environment. Refrain from applying feedstock for a week after introducing the worms to allow them to settle. Gradually introduce the feedstock over two to four weeks until the maximum processing capacity is reached.

To purchase worms and bedding material (vermicast) for a vermiculture unit, look under “worm

farms”	in	the	Yellow		Pages	or
advertisements			in	gardening
magazines.
Space availability

The type of vermiculture unit selected for on-site processing of compostable organics material needs to suit the availability of space for the site. For example, a stacking tray unit may offer the same feeding area but take up less floor space than a continuous flow unit.

When determining how much space is required for vermiculture processing, it is important to consider that other equipment is required for a vermiculture process to operate successfully.

This equipment includes:

�� size reduction equipment (eg. mixing tub, bucket and spade for soft food organics, shredder for cardboard);

�� material handling and feedstock preparation equipment (eg. buckets, mixing tubs, garden fork);

Definitions*

Source separation

Physical sorting of the waste stream into its components at the point of generation.

Compostable organics

Compostable organics is a generic term for all organic materials that are appropriate for collection and use as feedstocks for composting or in related biological treatment systems (e.g. anaerobic digestion). Compostable organics is defined by its material components: residual food organics; garden organics; wood and timber; biosolids, and agricultural organics.

Processing capacity

The maximum amount (mass or volume) of feedstock that can be added to a processing technology (e.g. composting technology) per unit time (e.g. per week) without causing system failure. System failure is evident when the processing technology produces problematic environmental emissions and/or declines in processing efficiency and/or produces product of unacceptable quality.

Bulking agent

An ingredient in a mixture of composting raw materials included to improve the structure and porosity of the mix. Bulking agents are usually rigid and dry and often have large particles (for example, straw or wood chips). The terms “bulking agent” and “amendment” are often used interchangeably. See also composting amendment.

Carbon to nitrogen (C:N) ratio

The ratio of the weight of organic carbon (C) to that of total nitrogen (N) in an organic material.

Anaerobic

In the absence of oxygen, or not requiring oxygen.

* Recycled Organics Unit (2001)

�� monitoring and maintenance

equipment (eg. thermometer,

pest deterrent devices);

9 . . . . . . . . . . . .

�� dry storage areas for bulking agent and area for blending feedstocks; and

�� washing up area (eg. sink, hose) and bin wash area.

Example

A summary of the steps required for determining the scale of vermiculture processing technology and the size of the vermiculture unit required for your operation is shown in Figure 3.

10 . . . . . . . . . . . .

Caution

The Recycled Organics Unit has been called out to fix many failed vermiculture processing operations.

Rectifying a failed system is much, much more work than managing a system effectively.

This package does not claim to be the only way for installing and maintaining a successful on-site vermiculture operation. However, applied research and extensive experience confirms that the processes and processing capacities communicated in this package provide a sound basis for problem free vermiculture processing, as is deemed necessary for successful application of this technology in C&I sector on-site applications.

11 . . . . . . . . . . . .

Information Sheet No. 5 Guide to installing a vermiculture unit

=

Where to locate a vermiculture unit

When installing vermiculture technology to process organic material, careful consideration should be given to the siting (or location) of the vermiculture units and the ancillary equipment.

Determining the most suitable location of an on-site, mid-scale vermiculture unit is dependent on a number of factors. These include:

�� accessibility;

�� maintaining climatic conditions

(shading and controlling

temperature and moisture);

�� security measures;

�� proximity to neighbours;

�� areas for storage of materials and feedstock preparation;

�� noise and odour considerations;

�� leachate;

�� pest exclusion; and

�� availability of services such as water and power if required.

Site selection for an on-site vermiculture installation is important both for efficiency of handling materials, and because worm activity is dependent upon environmental conditions including temperature and moisture.

Effective proper placement and management (of a unit of suitable size) will ensure effective operation without any adverse impacts on people or the environment (Plate 1).

Plate 1. Example of an on-site, mid-scale vermiculture unit installation in a nursing home.

The ROU is the NSW centre for organic resource management, information, research & development, demonstration and training

When locating a vermiculture installation, consideration of the required area should include the actual vermiculture unit, area for feedstock preparation and storage, and also area for equipment such as size-reduction equipment, monitoring and maintenance equipment.

This process of calculating the size of vermiculture technology required to process a given volume of material has been covered in Information Sheet No. 4.

Site selection

The selection of a suitable site for the location of a vermiculture unit is important in order to maintain both operational efficiency and vermiculture processing capacity. The location should be easily accessible from related operational activities, as feedstock material will need to be transported to the vermiculture installation.

The vermiculture units should be placed at a distance from neighbours and public areas but not in an area that is subject to vandalism.

Security measures should be in place to prevent any interaction with the treatment process by unauthorised personnel.

The placement of the vermiculture installation should be adjacent to or on route to the existing waste management and recycling area (Figure 1). This will increase the efficiency of the source separated collection system (see Information Sheet No. 2).

Vermiculture management activities

Storage of material

Ideally, food materials should be processed immediately to avoid any odour production. Compostable work practices may require short-term storage of compostable organics material prior to processing in the vermiculture unit. Short-term storage of spoiled food is common place in many commercial kitchens. Such spoiled food is often stored overnight in cool storage for disposal the next day. Storage areas should be kept clean and tidy and any spillage cleaned up immediately to prevent pest attraction and odour production.

Material should be stored in sealed containers (eg. in 80 L mobile garbage bins).

Feedstock preparation

A feedstock preparation area should be located adjacent to the vermiculture installation. This area should ideally include a small storage area to house equipment required for size-reduction, measuring and blending of the feedstock mixture, as well as clean-up equipment including brushes and hoses (Plate 2). Equipment such as garden forks and wheelbarrows or similar should be accessible to enable use of the vermicast product.

Details on the types of equipment required for feedstock preparation and supplier information is contained in Appendix No. 1.

Figure 1. Example of an on-site mid-scale vermiculture installation operated at a commercial catering establishment. This establishment generates primarily mixed food organics including a small amount of food-soiled paper. The material storage, feedstock preparation areas and vermiculture units are located adjacent to the waste disposal bins, the kitchen and the delivery dock.

. . . . . . . . . . . .

Plate 2. Equipment used for feedstock preparation and clean up including hose, garden forks, watering can, mixing tub, brushes and brooms.

Storing vermicast for use

When the vermicast product is removed from the vermiculture unit, it should be stored on site for use on the gardens of your organisation.

Specialist storage bins are available which aid in maturing the vermicast whilst in storage (Plate 3). Mobile garbage bins (MGB’s) are also a suitable storage unit. 120 L MGB’s are a good size for this purpose as they are still moveable once reasonably full.

See Information Sheet No. 7 for a guide to using the vermicast product.

Plate 3. Vermicast maturing bin.

Environmental and health considerations

Effective siting of the vermiculture units will minimise any adverse effects on people or the environment.

Environmental and health issues that need to be considered when siting vermiculture units include:

�� microclimate;

�� noise production;

�� odour production;

�� site hygiene;

�� sustainable loading rates; and

�� sustainable feedstock recipe.

These issues are very important for an effective vermiculture processing operation and with careful consideration, problems such as complaints from neighbours, pest attraction and health issues will be minimised.

Microclimate

Vermiculture units should be situated in an area where there is a degree of protection from extremes of weather (eg. temperature).

Worms are very susceptible to changes in climatic conditions. The acceptable temperature range for the Tiger worm (Eisenia fetida), a common species used in vermiculture systems, is 15 to 25 ^oC (Edwards, and Bohlen, 1996; Edwards, 1998) with an optimal temperature of 20^oC (Murphy, 1993).

This optimal temperature range refers to the bedding temperature and not the ambient air temperature. Control should be exercised over the environment of the worms to maintain temperatures within the ideal range to maximise the efficiency of the vermiculture process.

Definitions*

On-site, Mid-scale

A category of on-site composting or vermiculture-based technology with the ability to process between 20 and 250 kg of compostable organics per day. Such systems are usually comprised of an in-vessel processing unit (composting or vermiculture-based) and size-reduction equipment (eg. garden type petrol driven chippers or shredders). Procedures involved in the management of the processing system may involve a combination of manual labour and small mechanical equipment. Mid-scale systems are often used for the treatment of compostable organics produced by the commercial and industrial sector, hospitals and institutions etc.

Feedstock

Organic materials used for composting or related biological treatment systems. Different feedstocks have different nutrient concentrations, moisture, structure and contamination levels (physical, chemical and biological).

Leachate

Liquid released by, or water that has percolated through, waste or recovered materials, and that contains dissolved and/or suspended substances and/or solids and/or gases.

Processing capacity

The maximum amount (mass or volume) of feedstock that can be added to a processing technology (e.g. composting technology) per unit time (e.g. per week) without causing system failure. System failure is evident when the processing technology produces problematic environmental emissions and/or declines in processing efficiency and/or produces product of unacceptable quality.

Compostable organics

Compostable organics is a generic term for all organic materials that are appropriate for collection and use as feedstocks for composting or in related biological treatment systems (e.g. anaerobic digestion). Compostable organics is defined by its material components: residual food organics; garden organics; wood and timber; biosolids, and agricultural organics.

Continued page 4

3 . . . . . . . . . . . .

The temperature of the bedding material within a vermiculture unit can be influenced by the ambient air temperature and from direct sunlight. The lower the mass of bedding, and/or the higher the surface area to volume ratio of the bedding, the more it will be effected by daily fluctuations in air temperature and moisture.

When siting a vermiculture unit, ideally the units should be placed in an area not exposed to full summer sun. A location that is shaded in summer, yet sunny in winter is ideal.

Alternatively, an enclosed area may be suitable, but again only if the area is shaded and well ventilated so as to be relatively cool during hot summer periods. It may be possible to locate the vermiculture installation in an enclosed area where the temperature is already controlled via air conditioning.

If the units are located indoors in a temperature controlled environment, an ideal temperature range would be approximately 20-25^oC, consistent with the desirable temperature range for people. A reverse cycle air-conditioner (such as Plate 4) would provide good temperature control in a relatively constant environment such as the coastal New South Wales region.

Situating a vermiculture unit indoors is a luxury and is often not possible. Most vermiculture units are located outdoors and if this is the case, the minimum degree of climate control should be shade, especially in summer.

A shaded area such as a veranda is suitable for a vermiculture unit. However, if this is not possible, shade cloth covering the unit would also suit.

During summer months, damp hessian or old carpet should cover the surface of the bedding mass to prevent the units from drying out (Windust, 1997). In extreme temperatures, evaporative cooling can be used to lower the temperature of the entire vermiculture unit. This involves draping a wet cloth over the unit and moving air over the unit by the use of a fan or a breeze (Appelhof, 1997).

Additional layers of hessian, carpet underlay or similar can also be placed over the bedding surface during colder months to help insulate the bedding and to retain heat generated by the decomposition process.

Plate 4. Example of a reverse-cycle air-conditioner used for climate control.

Noise production

The production of noise from size-reduction equipment, such as a shredder or chipper, may pose problems if this equipment is located in close proximity to offices, neighbours or public areas.

Such equipment should be operated in accordance with proper occupational health and safety procedures, including the wearing of ear and eye protection.

Odour production

The generation of offensive odours may occur if a vermiculture unit is not managed effectively.

If a vermiculture unit produces odours, management procedures should be implemented to identify and rectify the problem. These management procedures are covered in Information Sheet No. 6.

The production of odours can also

result in the attraction of addition pests and vermin relative to current waste disposal practices. This may pose health risks and should be rectified immediately.

4 . . . . . . . . . . . .

Site hygiene

Ensuring the vermiculture installation is clean and hygienic is important to minimise odour production and to avoid potential occupational health and safety issues.

Any spillage of compostable material, vermicast or leachate should be cleaned up immediately. No food materials should be left exposed as this will attract pests and create odour problems.

Ensure staff wear gloves at all times when handling materials and that they wash their hands after any contact with the vermiculture operation. This will avoid cross contamination with any germs that may be present on spoiled food material.

Sustainable loading rates

The application of feedstock to a vermiculture unit at sustainable rates will minimise the accumulation of unprocessed feedstock within the units. Feedstock accumulation will result in temperature increases and will make the unit undesirable to the worm population. If this situation is not rectified, system failure will occur.

Loading rates depend on the type of organic material within the feedstock mixture. See Information Sheet No. 4 for some feedstock recipes and suitable loading rates.

Suitable feedstock recipe

The application of compostable organics to a vermiculture unit will only be successful if the material is in a suitable form for vermiculture processing. This involves only processing suitable organics, size reducing the material, amendment with a bulking agent and ensuring a suitable moisture content and structure. Information Sheet No. 4 has a comprehensive guide to feedstock preparation that will help you to produce a suitable feedstock for successful vermiculture processing.

Other considerations

Further considerations that should be addressed when installing a vermiculture unit include:

�� leachate production;

�� pest attraction;

�� related services; and

�� security.

Leachate production

The generation of leachate from a vermiculture unit is undesirable and can be rectified by effective management procedures. These are covered in Information Sheet No. 6.

If a vermiculture unit produces leachate, this liquid must be collected to avoid potential problems such as odour. The leachate should be collected and either re-treated in the vermiculture unit (small volumes only) or removed. See Information Sheet No. 7 for a guide to using leachate (vermiculture liquid).

Pest attraction

When installing a vermiculture unit, opportunities for pest attraction should be minimised.

Where units are enclosed in small areas, this may include the installation of pest deterrent devices.

Crawling insects can be deterred by standing the units in moats (buckets of water and detergent, Plate 5 or in salt water). Alternatively, the legs of the vermiculture unit can be coated in axle grease or sticky pest traps (see Appendix No. 1 for equipment suppliers).

Flying insect pests can be deterred using various baits or traps, for example fluorescent (black-light) zappers or devices such as in Plate 6.

Plate 5. Legs of free-standing vermiculture units can be placed in buckets of water and detergent to prevent crawling pests such as ants from entering the units.

Plate 5. Flying insect attraction devices. See Appendix No. 1 for supplier details

5 . . . . . . . . . . . .

Ensuring the area is thoroughly clean after any feedstock preparation, and storing all materials in sealed containers, will minimise pest attraction and probably represents a significant improvement over current practice.

Related services

Services such as water, and in some instances power, are required for effective vermiculture operations.

The availability of these services should be considered when installing vermiculture units and locating storage areas.

Water supply will be required for adding water to units during summer months, and for washing containers. Wash water from cleaning containers should be disposed of in gardens or the sewer.

Electricity may also be required for the operation of specific vermiculture technologies, but is generally not necessary.

Security

Security concerns (eg. vandalism) are often over stated. Be aware that the units contain decomposing material, which in itself usually provides necessary deterrent for potential vandals. The only serious instances of vandalism, in the authors experience, have resulted from locating units in areas already known to be subject to vandalism and/or are secluded out of hours congregation areas.

Some common sense is required when installing your vermiculture unit. For example, do not install units where they will disrupt existing popular activities and therefore give rise to antagonistic attitudes.

6 . . . . . . . . . . . .

Information Sheet No. 6
Management and maintenance of a vermiculture unit
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		Best practice management & maintenance	temperature, moisture content, and sampling vermicast; and

The ROU is the NSW centre for organic resource management, information, research & development, demonstration and training

Feedstock preparation & application

The preparation of a suitable feedstock is crucial in maintaining a successful vermiculture unit.

Many problems can result if the feedstock is inappropriate to the vermiculture unit. These can include:

�� feedstock too moist – resulting in anaerobic (low oxygen) conditions, worms need oxygen to survive;

�� feedstock too dry – not suitable for worm habitation;

�� feedstock recipes that contain components that are difficult to process by vermiculture technology – such as seafood, dairy products and hard materials (eg. bones);

�� feedstock loading rate too high – too much feedstock applied to the unit resulting in feedstock

accumulation,		anaerobic	(low
oxygen)	conditions		and
subsequent worm death;

�� feedstock too acidic/alkaline/ high in salts; or

�� feedstock particles too large – size reduction is necessary for effective processing.

The preparation of an appropriate feedstock involves careful consideration of the raw feedstock components. Vermiculture units process a mixture of compostable organics more readily than monostreams of single organic materials, for example, just bakery waste (Recycled Organics Unit, 2000).

A number of feedstock recipes have been given in Information Sheet No. 4 and these recipes are an excellent guide to preparing a suitable feedstock. Plates 4, 5, 6 and 7 show the steps in preparing a mixed fruit and vegetable feedstock.

The actual proportions of raw ingredients in a feedstock are not as crucial as the overall feedstock texture based on structure and moisture content. The addition of a bulking agent will influence the feedstock texture.

The addition of a bulking agent, such as paper or cardboard, is necessary to provide an adequate environment for worm habitation. Bulking agents increase the particle size of the feedstock which increases porosity and the carbon to nitrogen (C:N) ratio. These factors are essential for a feedstock suitable for processing by a vermiculture unit

The addition of moisture may also be necessary if the feedstock contains raw ingredients that are quite dry, for example breads.

The ‘fist test’ can be used when preparing a feedstock to estimate the moisture content of the material.

The method for performing the fist test is given later in this Information Sheet under ‘Moisture Content’.

This method is used for determining the optimum bedding moisture content. However, since the worms will inhabit the feedstock whilst they process it, the feedstock moisture content should also be at this optimum moisture content.

Plates 4, 5, 6 and 7. Preparation of mixed fruit and vegetable feedstock. Raw size-reduced fruit (far left) combined with cardboard bulking agent (left). Mixed thoroughly (right). Final feedstock of size reduced mixed fruit and vegetables with cardboard bulking agent (far right). Note the good structure present in the final feedstock mix. See Information Sheet No. 4 for more information.

3 . . . . . . . . . . . .

Monitoring & management of vermiculture units

Effective monitoring and management of vermiculture units is essential for the process to operate effectively and efficiently.

The monitoring and management procedures described in this Information Sheet are quick and easy to perform ‘field tests’.

The procedures described below are effective ways of ensuring a vermiculture process is operating effectively. It should be noted, however, that a wider range of testing procedures might be relevant for specific installations.

Monitoring procedures will be described for:

�� worm activity;

�� feedstock accumulation;

�� oxygen;

�� temperature;

�� moisture content; and

�� sampling vermicast.

Suppliers and approximate prices of associated equipment required for these tests are detailed in Appendix

1.

Details of further tests, performed in a laboratory, that maybe necessary to ensure the final vermicast product is safe for use will also be described. These include taking a sample to be analysed for:

�� pathogens; and

�� heavy metal concentrations.

Note that these tests may only be relevant if the operator intends to sell the vermicast product commercially.

A number of more complex tests can be performed during vermiculture processing, for example salt content

4 . . .

(measured by the electrical conductivity test), pH, and total Definitions* carbon and nitrogen content. These tests, however, require laboratory Compostable organics analysis and are not normally Compostable organics is a generic term for all necessary for on-site, mid-scale organic materials that are appropriate for _processing. collection and use as feedstocks for

composting or in related biological treatment A form for recording weekly systems (e.g. anaerobic digestion). _{management and maintenance} Compostable organics is defined by its

material components: residual food organics;

procedures and for monitoring _{system performance has been} garden organics; wood and timber; biosolids, included in this Information Sheet ^{and agricultural organics.}

^{(Form 1).} Best Practice _{Monitoring & testing safety} For any area of waste management this represents the current ‘state-of-the-art’ in ^tips achieving particular goals. Best practice is dynamic and subject to continual review and

The monitoring and management procedures discussed here are not ^improvement. hazardous however a few safety precautions need to be observed. ^{On-site, Mid-scale}

A category of on-site composting or _{�� Gloves – should be worn when} vermiculture-based technology with the ability _{handling feedstocks and} to process between 20 and 250 kg of compostable organics per day. Such systems

vermicast.

are usually comprised of an in-vessel _{�� Apron – protects clothing whilst} processing unit (composting or vermiculture-based) and size-reduction equipment (eg. ^{handling material and preparing} garden type petrol driven chippers or ^feedstocks. shredders). Procedures involved in the management of the processing system may ^{�� Safety glasses – should be} involve a combination of manual labour and ^{worn during size reduction} small mechanical equipment. Mid-scale ^procedures. systems are often used for the treatment of compostable organics produced by the

^{�� Ventilation – activities such as} commercial and industrial sector, hospitals and size reduction and feedstock _{institutions etc.} preparation should be conducted in a well-ventilated area. Feedstock

Organic materials used for composting or

�� Equipment – should be used related biological treatment systems. Different safely, and tasks should be feedstocks have different nutrient supported by standard operating concentrations, moisture, structure and procedures that define safe and contamination levels (physical, chemical and

effective operating practice. biological).

�� Hygiene – if handling materials Vermicast or feedstock, hands should Solid organic material resulting from the biological transformation of compostable

always be washed with soap and _{warm water afterwards.} organic materials in a controlled vermiculture

process.

Continued page 5

. . . . . . . . .

Indicators of system stress

Effective monitoring and management of a vermiculture unit will result in a reliable and efficient organics managment system. Particular occurrences within the system may indicate system success or failure and these should be regularly investigated as indicators of system health.

The hierarchy of system performance indicators (shown in Figure 2) is as follows:

1. Worm activity – is the first indication that a system is stressed. Worms will attempt to escape the vermiculture unit if conditions are unsuitable for habitation.
2. Feedstock accumulation – feedstock will accumulate if the worms are no longer processing it but are attempting to escape. The feedstock will accumulate and cause the conditions to be even more unsuitable for worm habitation.

3.	Oxygen	–	if	feedstock		4.	Temperature			–		finally
	accumulates, oxygen levels will						temperature will rise within the
	decrease and cause				anaerobic		unit	as	the		feedstock
	conditions. This will add to the						accumulates and decomposes.
	uninhabitable conditions of the
	unit.

Indicators of system stress

Figure 2. Hierarchy of indicators of system stress. Regular monitoring of indicators of stress will ensure problems are identified promptly, allowing operators to correct these problems to maintain overall performance.

1. Worm activity is the first indicator that a vermiculture unit is performing well or is under stress. Worm activity should be monitored regularly and any change in activity should be noted.

2. Feedstock will accumulate if a unit is not adequately processing the

Feedstock accumulation feedstock. If feedstock is accumulating, indications are that the processing rate is too high or the feedstock is not suitable.

3. Oxygen levels will become low (<10%) if the unit is stressed. If oxygen levels drop, management should be implemented such as tossing of the beds and the cause of the oxygen level drop should be investigated.

4. Temperatures will be high (>30 ^oC) if the unit is stressed. Temperature should be regularly monitored to prevent temperatures becoming this high. Temperature is the final indication of a stressed vermiculture unit.

5 . . . . . . . . . . . .

=Worm activity

Worm activity is an effective qualitative method for assessing system performance.

Worms will behave according to the degree of stress that they are under. If the vermiculture unit is not suitable for habitation by worms, they will attempt to escape. For this reason, observations of worm activity are usually the first indication that a vermiculture unit is under stress.

Worm activity should be monitored regularly using a classification system. An example of such a system is shown in Table 1. This system uses various categories of worm activity to define the performance of a vermiculture unit.

Some examples of worm activity exhibiting system stress are shown in Plates 8, 9 and 10. These units are under significant stress and maintenance procedures should be performed well before a vermiculture unit reaches these levels.

If worm activity is monitored regularly, system stress and ultimate system failure can be prevented. The method for observing worm activity is given below.

Materials

�� Classification system of worm activity (such as Table 1).

�� Gloves

Methods

1. Worm activity should be monitored within a vermiculture unit at least once per week.
2. Observe worm activity prior to feeding.
3. Scrape back a section of feedstock to expose the bedding surface (see Figure 3 for a description of the zones of worm habitation).
4. Observe the regions were worms are congregating, for example, if the majority of worms are throughout the feedstock then the system is performing well, but if the worms are on the edges of the feedstock or feeding from below the feedstock, the system is under some stress.
5. Record observations.

Management

Management of stressed vermiculture units will vary depending on the category of worm activity. The regions that the worms do not inhabit tend to indicate where the problems are occurring. These may include:

�� Worms are not in feedstock but feeding from below or edges of feedstock – this indicates the feedstock is unsuitable which may be due to particle size, moisture, temperature, or feedstock content. The feedstock recipe should be revised.

�� Worms are actively trying to escape the unit – the system has failed and all aspects should be reconsidered (ie. feedstock, bedding depth, climate control, monitoring and maintenance procedures).

=

Plates 8, 9, and 10. Worm activity indicating severe system stress. Worms are trying to escape vermiculture unit through base (left), worms are on top of the hessian covering and not in the feedstock layer (centre), worms are trying to escape unit through unit rim (right).

6 . . . . . . . . . . . .

Table 1. Observations of worm activity and indicators of vermiculture unit performance.

Category	System Performance	Diagnostic Indicator
A	No system stress – optimal/good performance	�� Worm population mostly located in feeding layer. No detrimental temperature increase (<30 oC).
	Some system stress –	�� Worm population largely in feeding layer. Some below feeding layer and some
B	moderate system	trying to escape unit indicated by worms massing around unit rim. Some
	performance	detrimental temperature increase in feeding layer (>30 oC).
	Moderate/high system	�� Population largely around sides of unit and trying to escape through unit lid or
C1	stress – sub-optimal	accumulating on	surface of	hessian.	Significant	detrimental	temperature
	performance	increase in feeding layer (30 – 35 oC).
C2	Moderate/high system stress – sub-optimal performance	�� Little worm population in feeding layer. Most worms feeding from underneath feeding layer. No substantial detrimental temperature increase (<30 oC).
D	System failure	�� No worms in feedstock. Worm population extensively swarming in corners of unit or around unit lid and escaping unit.

Form 1. Weekly management and maintenance form for an on-site vermiculture unit. Management and maintenance procedures should be performed at least once per week to ensure the unit is operating efficiently.

	Weekly Management and Maintenance Form
	Monitoring
Date	Worm activity (see criteria above)	Feedstock accumulation (cm)	% Oxygen concentration		Temperature (oC)
			Centre of feedstock	Below bedding surface	Centre of feedstock	Below bedding surface
Maintenance
Date	Add water (L)		Tossed beds		Removed leachate (L)
General comments
Date	Comment or description of weekly performance					Staff initial

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Feedstock accumulation

The accumulation of feedstock within a vermiculture unit should be monitored to ensure the loading rate for the unit is adequate.

If feedstock accumulates within a unit, too much feedstock is being applied and the worms do not have time to process it before the next feeding occurs.

Feedstock accumulation can result in problems such as anaerobic (low oxygen) conditions, odour production, worm stress and ultimate system failure.

The method for determining feedstock accumulation is given below.

Materials

�� Ruler

�� Gloves

Method

1. Feedstock accumulation within a vermiculture unit should be monitored at least once per week.
2. Scrape back a section of the feedstock layer to reveal the bedding surface as shown in Plate 11 (see Figure 3 for a

description of the zones of worm habitation).

1. Measure the amount of feedstock that has accumulated on top of the bedding material (Plate 12).
2. Record this measurement.

Management

An accumulation of unprocessed feedstock of greater than 20 cm can be detrimental to the vermiculture unit.

Feedstock accumulation indicates that the vermiculture unit is under stress. This stress may be due to:

�� Loading rate too high – too much feedstock is being applied and the worms do not have time to process it. Decrease the loading rate to allow thorough processing.

�� Feedstock unsuitable – the feedstock recipe may be undesirable to the worms and the recipe should be revised.

Plates 11 and 12. Measuring the accumulation of feedstock within a vermiculture unit. Pull back an area of the feedstock layer to reveal the interface with the bedding material (left). Using a ruler, measure the thickness of the feedstock layer above the bedding material (right).

8 . . . . . . . . . . . .

Oxygen

Oxygen is essential for vermiculture processing. Worms and aerobic microorganisms require oxygen to live.

Oxygen in a vermiculture unit has an effect on the rate of decomposition and on the production of odour. Consequently, maintaining an aerobic (high oxygen) vermiculture environment is the key to maximising the rate of organic decomposition and minimising odours.

The concentration of oxygen in air is approximately 21%. To minimise odour generation and to maximise the rate of vermiculture processing, the concentration of oxygen within a vermiculture unit should be kept above 10% (Recycled Organics Unit, 2000).

The method for monitoring the oxygen concentration of a vermiculture unit is given below.

Note that an oxygen meter can be expensive – approximately $2,400. Although a vermiculture unit can be managed without one, it can be useful for quickly diagnosing system problems. The meter shown in Plate 13 is a combined temperature and oxygen meter. Thus, a separate temperature meter (eg. in Plate 15, see next section), is not necessary.

Materials

�� Hand-held oxygen meter with a type of meter, a warm-up period of up to 5 minutes may be required.

1. If needed, calibrate the instrument by aspirating the cell (squeezing and releasing the rubber bulb to draw fresh air into the unit). Check the display to ensure it is reading 21% (most meters round the result to the nearest whole number). Adjust calibration screw if required.
2. Oxygen readings should be taken in the zones of worm habitation – the centre of the feedstock layer and below the bedding surface to a depth of 5 cm (see Figure 3). Insert the probe into these regions and aspirate the bulb until the reading becomes steady (Plate 14).
3. Record readings. The average of a number of readings for each zone can be taken for a more representative reading.

Management

If the oxygen probe indicates the concentration of oxygen within the system is insufficient (ie. <10%), management procedures should be implemented. These may include:

�� Tossing – this aerates the system by lifting (with a garden fork) and loosening the material without burying feedstock. See the section on ‘Tossing’ in this

Plate 13. Example of a combined Temperature/Oxygen meter (Demista, USA).

Information Sheet.

�� Loading rate – if the feedstock is building up, the lower regions may become anaerobic (low in oxygen) due to compaction. The loading rate may need to be decreased to allow the worms time to process the feedstock.

�� Feedstock recipe – if the feedstock is too moist or has a structure with particles that are too small, oxygen will be unable to penetrate this layer and it will be unsuitable for processing by the worms. The feedstock recipe should be revised.

�� Bedding thickness – the overall thickness of the vermiculture unit bedding should not exceed 45 cm as compaction can result. Harvesting of the vermicast may be required to decrease the bedding thickness. See the section on ‘Harvesting Vermicast’ in this Information Sheet.

probe at least 50 cm long (Plate

13). Plate 14. Insert oxygen probe into the desired zone and aspirate the bulb until the reading becomes steady.

�� Gloves

Method

1. Oxygen concentrations within a vermiculture unit should be measured at least once per week.
2. Turn the meter on and check battery status. Depending on the

9 . . . . . . . . . . . .

Temperature

Worms are living organisms that require particular conditions for survival. Temperature is one of these conditions and is a factor that influences the ability of worms to process compostable organics.

Appropriate temperature ranges need to be maintained within a vermiculture unit and temperature should be monitored as an indicator of system health.

There are two distinct zones within a vermiculture unit that can exhibit temperatures that will influence the ability of worms to process organic materials. These zones are: the feedstock layer and the bedding material. Figure 3 shows the location of these zones within a vertical loading vermiculture unit.

These zones can exhibit different temperatures due to the variation in the amount of decomposing organic material present in each layer.

Heat is produced in vermiculture units by microorganisms when they consume food (organic materials). Heat builds-up in the unit due to the feedstock acting as an insulator to the surrounding environment.

The feedstock layer is generally higher in temperature than the bedding material of the unit due to the higher content of decomposing organic material in this zone. Measuring the temperature for both unit is dependent on the type of worms inhabiting the units (see Information Sheet No. 4 for details on worms suitable for vermiculture processing).

Eisenia fetida or Tiger worm is a common worm species used in vermiculture units. The ideal temperature range for the Tiger worm is 20 to 25^oC.

A standard method for monitoring temperature is given below.

Materials

�� Hand-held temperature meter with a probe at least 50 cm long (Plate 13 – a combined temperature/oxygen probe or Plate 15). The device can be analogue or digital.

�� Gloves

Method

Temperature readings should be taken in the zones of worm habitation: the centre of the feedstock layer; and below the bedding surface to a depth of 5 cm (Figure 3).

1. Temperatures within a vermiculture unit should be measured at least once per week.
2. Insert the temperature probe into the centre of the feedstock layer

and record the temperature (Plate 16). Repeat at a number of locations across the surface. The average of these readings can be taken for a more representative assessment.

1. For the bedding temperature, scrape back a section of the feedstock to reveal the interface between the feedstock layer and the bedding surface (Plate 17). Insert the probe to a depth of 5 cm (Plate 18). A piece of tape can be placed around the temperature probe to mark this 5 cm depth. Again, an average of a number of readings can be taken.
2. Record readings.

Management

If temperatures within a vermiculture unit are found to be unsuitable, management procedures should be implemented to rectify this problem, particularly if temperatures have been exhibiting an upward trend over time. This upward trend indicates emerging problems that must be addressed before the vermiculture process deteriorates. Management procedures may include:

�� Climate control – placing the

units in a more controlled

environment to prevent climatic

Plate 15. Example of a temperature probe (REOTEMP, USA).

of these zones is important to understand the processes occurring within the unit.

Temperature can be influenced by the amount of feedstock that has accumulated within the unit. Temperatures can also vary due to other factors such as limited moisture or air (Recycled Organics Units, 2001b).

The optimum temperature for the bedding material in a vermiculture

10 . . .

. . . . . . . . .

conditions from influencing the feeding. �� Bedding material too deep – if processing (eg. frosts). If the bedding material has temperatures are too low (ie. ^{�� Feedstock recipe – if the} accumulated to a depth of <15^oC), placing some layers of ^{feedstock is not being processed} greater than 45 cm, temperatures _{hessian or cardboard over the} by the worm population and the

within the unit can rise. This is feedstock layer can insulate the ^{temperatures are increasing, the} due to the insulating effect of the unit and retain heat. See ^{feedstock recipe may not be} bedding and the feedstock layer. Information Sheet No. 5 for ^{suitable (eg. too moist/dry,} Harvesting vermicast will reduce details of climate control. ^{components not suitable, more} this bedding depth and lower the

bulking agent required). The _{temperature of the bedding} �� Loading rate – decreasing the feedstock recipe should be

material over time. amount of feedstock being reviewed in this case. applied to the unit at each feeding. If too much feedstock is applied to a unit, temperatures will rise, so decreasing the loading rate will allow the worms to process the feedstock more thoroughly before the next

Figure 3. Zones of worm activity within a vermiculture unit that can exhibit distinct changes in oxygen concentration and temperature. These zones are: the feedstock layer, and below the bedding surface. An oxygen/temperature probe should be inserted into these zones to monitor the conditions for worm habitation.

Plate 16. Insert probe into the					Plate	17.		Scrape		back	the	Plate 18. Insert probe 5 cm below
centre	of	the	feedstock	layer	interface		between		the feedstock			the bedding surface (Zone 3 on
(Zone 1 on Figure 3 above).					layer and bedding material (Zone							Figure 3 above).
					2 on Figure 3 above).

11 . . . . . . . . . . . .

Moisture content

Moisture content is the proportion of a material’s total weight that is water. It is often expressed as a percentage. The non-water portion of a material is referred to as dry matter (Recycled Organics Unit, 2001c).

Moisture content is an important variable when monitoring vermiculture units. The bedding of a vermiculture unit must be sufficiently moist to allow worm habitation. However, if the moisture content is too high, anaerobic (low oxygen) conditions can develop.

The optimum moisture content for vermiculture processing using mixed worm stock in a temperate environment is approximately 80% (Recycled Organics Unit, 1999).

A simple method for estimating the moisture content of vermicast is given below. This method is based on the ‘fist test’ (Federal Compost Quality Assurance Organisation, 1994).

The ‘fist test’ provides a rough estimate of moisture content but cannot be used to estimate the volume of water required to increase the moisture content of a material.

The ‘fist test’ simply gives an indication as to whether a material may be ‘too dry’ or ‘too wet’ for vermiculture processing.

Materials

�� ~ 1 L of fresh test sample

�� Gloves

Method

1. Press a sub-sample into the flat of hand (Plate 19).
2. Close hand around the sample and press firmly (Plate 20).

Plates 19 and 20. Pictures showing how to conduct the Fist Test for approximating moisture content. Press a sub-sample into the flat of hand (left). Close hand around the sample and press firmly (right).

Plates 21 and 22. Sample with suitable moisture content for vermiculture processing glistens slightly - some water released between the fingers (left). Sample too dry for vermiculture processing (right). Sample crumbles without further action when the fist is opened.

Plates 23 and 24. Sample too wet for vermiculture processing (left and right). The sample deforms significantly after the fist is opened, does not fall apart when pressure is applied or if a large amount of water is released, the sample is too wet for vermiculture processing (right).

3. Open fist and evaluate structure of sample.

12 . . . . . . . . . . . .

If the sample is sufficiently wet for vermiculture processing, it should glisten slightly, that is, some water should be released between the fingers (Plate 21).

If the sample crumbles without further action when the fist is opened, the sample is too dry (Plate 22).

If the sample deforms significantly after the fist is opened, does not fall apart when pressure is applied or if a large amount of water is released, the sample is too wet for vermiculture processing (Plates 23 and 24).

Management

Moisture can be added to a vermiculture unit using a watering can (Plate 25). Moisture should only be added in the morning as a very moist environment overnight may cause worms to leave the unit.

Problems that can be encountered if the bed moisture content is not suitable include:

�� Slumping – the bedding material is too moist and falls through the vermiculture unit into the collection tray.

�� Anaerobic (low oxygen) conditions – the bedding is too moist and becomes compacted resulting in low oxygen conditions and worm death.

�� Leachate production – excess leachate can result in pest attraction and problems of disposal.

These problems of excessive moisture within a vermiculture unit may result from a feedstock mixture that is too wet. If such problems occur, the recipe should be revised to decrease the moisture content of the feedstock. Increasing the proportion of bulking agent or not adding water to a feedstock recipe can help to decrease the moisture content.

The ‘fist test’ can also be used to estimate the optimum moisture content for a feedstock recipe.

Plate 25. Addition of water to a vermiculture unit. See Appendix No. 1 for information on equipment suppliers.

13 . . . . . . . . . . . .

Sampling

Samples of the final vermicast product should be analysed if the product is to be sold in a commercial context, or in instances where the feedstock is likely to contain high concentrations of microbial pathogens. This however is not practical for most C&I sector organisations.

If microbial analysis is to be performed, samples should be taken and analysed in a commercial laboratory. Laboratories accredited by the National Association of Testing Authorities (NATA) are recommended as they are assessed for testing proficiency on a regular basis (Recycled Organics Unit, 2001d).

The method for sampling of a vermiculture unit is given below.

Materials

�� Tough polythene bag (Plate 26)

�� Waterproof marker

�� ~ 1 L of fresh test sample

�� Gloves

�� Cool pack with ice brick

Method

1. Take a sample of vermicast (approximately 1 L) that represents the overall vermicast product. This can be done by sampling from a number of representative locations and combining the materials into one sample.
2. Seal the sample in a polythene bag and clearly label (eg. type of sample, date of sampling and client name) with a waterproof marker.
3. Tape or tie the bag securely and place in a cool pack (eg. esky)

with an ice brick. Samples must be kept at approximately 4^oC.

4. Send to the laboratory by courier on the same day of sampling.

Human Microbial Pathogens

Analysis for pathogens such as E. coli and Salmonella spp. is important particularly for vermicast produced from feedstocks containing decomposing meat, as contamination by these human pathogens is likely (Recycled Organics Unit, 2000).

Testing for human microbial pathogens should be performed by a NATA accredited laboratory according to methods reported in the NSW EPA Biosolids Guidelines (1997).

If human microbial pathogens such as E. coli and Salmonella spp. were detected in the final vermicast product above a certain level,

Plate 26. Materials required to sample vermicast for commercial laboratory analysis.

restrictions on the use of the product would be applied.

Further information

For more information on producing a quality vermicast product, obtain a copy of “Producing Quality Compost: Operation and management guide to support the consistent production of quality compost and products containing recycled organics” produced by the Recycled Organics Unit or visit http://www.recycledorganics.com.

Alternatively, Appendix No. 2 in this Best Practise Guideline contains a brief informative on the vermicast product standard.

14 . . . . . . . . . . . .

Maintenance of vermiculture Tossing Method units

‘Tossing’ of bedding material is an _{1. Slide the fork into the bedding} Maintenance procedures should be effective way of aerating or _{material to the depth of} performed regularly on vermiculture increasing the oxygen within a _{approximately half the prong} units to prevent problems from vermiculture unit. _{length (Plate 27).} developing.

^{Tossing involves the lifting and} 2. Gently pivot the fork down so ^{Maintenance procedures include: loosening of material without} that the prongs lift the bedding inverting any of the feedstock. A _{material gently (Plate 28).} ^{�� tossing;} garden fork is ideal for manual

tossing as it minimises worm 3. Lift the fork until the bedding ^{�� odour prevention;} casualties. See Appendix No. 1 for material opens slightly allowing air to penetrate the unit and any

�� leachate collection; ^{equipment suppliers.} compaction is loosened (Plate _{�� pest deterrence;} Tossing should not excessively _29).disturb the vermiculture unit. The �� harvesting vermicast; and process of tossing is given below. 4. Slide the fork out without inverting material or removing �� light. ^Materials material from the unit (Plate 30).

^{�� Garden fork.} 5. Repeat across surface of vermiculture unit.

Plate 27. Slide the fork in gently to a depth of Plate 28. Gently lift the bedding material to aerate. approximately half the length of the prongs.

Plate 29. Loosen the bedding material without inverting or Plate 30. Gently slide the fork out without removing burying feedstock. material.

15 . . . . . . . . . . . .

Odour prevention

To prevent health and environmental issues such as odour development, areas used for feedstock preparation, storage and processing should be kept clean and tidy at all times.

Odours produced by a vermiculture unit indicate that the unit is unhealthy. In a healthy unit, worms can remove odour from putrescible organics within 24 to 48 hours (Edwards, 1998).

Odours tend to occur if the unit is progressing to anaerobic (low oxygen) conditions. Anaerobic microorganisms that thrive in this environment cause these offensive odours.

If a vermiculture unit produces odour, maintenance is necessary to increase aeration and to determine the cause of the anaerobic conditions.

The feedstock recipe should be revised as well as the loading rate to ensure that excessive amounts of feedstock are not accumulating. Periodic tossing will help in reducing the production of odours by aerating the unit. However, odour production is an indication of an unhealthy unit and the cause of this should be investigated and prevented rather than just treating the symptoms.

Leachate collection

Vermiculture units can produce leachate as microorganisms release water during the natural decomposition of organic materials.

Excessive moisture within the unit will percolate to the bottom layers where drainage must be allowed to occur. Drainage and collection of this leachate is important to prevent saturation of the vermiculture unit and attraction of pests (Plates 31 and 32).

Excessive moisture levels will lead to high leachate production and may cause problems with waterlogging if the leachate is not able to freely drain. Collection devices need to be regularly monitored to ensure accumulation of liquid does not occur within the unit.

The addition of moisture may need to be reduced if excess leachate is being produced or if the unit becomes too moist for worm habitation. The feedstock recipe may also be the cause of leachate production and should be revised, for example, by adding more bulking agent.

Pest deterrence

Pests can be attracted to vermiculture processing areas and can include vermin, ants and insects.

Problems can occur if such pests (eg. insects) are able to enter the unit and breed as eggs and larvae can make the unit undesirable to the worm population.

The potential for pests to interfere with a vermiculture unit should be minimised by installing pest deterrent devices.

Methods for deterring pests include:

�� Ensuring all areas are kept clean

especially		after	feedstock
preparation.		All	feedstocks
should	be	sealed	when	in
storage.

�� Free-standing vermiculture units should have the legs of the units placed in buckets of water and detergent or coated in axle grease or sticky pest traps (see Appendix No 1). This acts as a barrier for crawling insects such

Plates 31 and 32. Leachate collection tray (left). Any leachate produced should be removed from the vermiculture unit (right) and either disposed of or stored in a sealed container. The liquid can be used as a liquid fertiliser for plants. See “How to Use Recycled Organics Products” published by the Recycled Organics Unit (2001d) for more information.

16 . . . . . . . . . . . .

Plate 33. Legs of vermiculture units placed in buckets of water and detergent to Curing involves the stabilisation of prevent crawling insects, such as ants, from entering the system. _{the organic materials as the rate of}

as ants (Plate 33).

�� Installing flying-insect catching devices such as fluorescent (black) lights and sticky flypaper (Plates 34, 35 and 36).

�� Enclosing the vermiculture units within a room with an extractor fan and minimising odour production.

It should be noted however that vermiculture is an ecosystem in itself and that cohabitation of various organisms will exist. Only those organisms that are a direct pest and that interfere with the vermiculture process such as ants, flies and particularly vermin need to be controlled.

Harvesting vermicast

The benefits of treating residual organics in a vermiculture unit is that a useable end product, vermicast, is produced.

Harvesting of this product occurs when the organic materials from the feedstock have been processed and the worms have moved out of this region.

When harvesting vermicast, it is often beneficial to allow the material to rest or cure before use. Whilst it is possible to use vermicast immediately after harvesting, curing is a way of completing the decomposition process and results in a more finished product (Grossman and Weitzel, 1997).

decomposition slows and the remaining organic material is consumed (Recycled Organics Unit, 2000b).

Curing can be accomplished by storing the vermicast in a way that allows oxygen to penetrate the material. This can be done in modified 240 L mobile garbage bins. A bin that has a perforated raised floor and air holes on the sides is an ideal unit to use (Plate 37).

Curing should occur for approximately 4 weeks. Information Sheet No. 7 provides details on using the vermicast product.

Plate 37. Modified mobile garbage bin used for curing of vermicast. See Appendix No. 1 for supplier information.

Plates 34, 35 and 36. Attraction device for flying insects. Nelson Electro Stick (left), Efekto Fly Trap (centre) and Yard Guard (right).

17 . . . . . . . . . . . .

Light

Light can be used to ensure the worm population remain within the vermiculture unit. Worms can migrate out of the units under particular conditions of cool air temperatures and 100% humidity (Wilson, 1999).

To prevent migration of a worm population a light shining on to the vermiculture unit can be used. Worms will only migrate at night and therefore a continual light source will prevent this situation from occurring.

Timetable of management and maintenance procedures

An example of an effective monitoring and maintenance regime is shown in Table 2.

This timetable shows the monitoring and maintenance regime for a small restaurant using a top loading continuous flow vermiculture unit to process mixed food organics.

The timetable details how often these procedures should be undertaken and gives the approximate time required for the procedures.

Table 2. Timetable of monitoring and maintenance for a small restaurant processing mixed food organics. The vermiculture units used in this scenario are top loading continuous flow systems with 3 m² of processing surface area. The feedstock consists of pre-consumer fruits and vegetables and post-consumer plate scrapings (mixed food organics). The restaurant is open 6 days per week and feeding occurs after closing each day so the compostable organics need not be stored prior to feeding.

Activity		Time required (hours)
	Monday	Tuesday	Wednesday			Thursday	Friday	Saturday	Sunday
	Feedstock
Feedstock preparation Feeding of vermiculture units	closed	0.5 0.5		0.5 0.5	0.5 0.5		0.5 0.5	0.5 0.5	0.5 0.5
	Monitoring
Oxygen Temperature Moisture content Worm activity Feedstock accumulation	closed	0.25 0.25 0.25 0.25			As required
	Maintenance
Tossing		0.5
Leachate collection	closed				As required
Pest deterrence					0.5
Harvesting vermicast					As required
	Clean-up
Washing up, site hygiene etc.		0.5		0.5	0.5		0.5	0.5	0.5
Total time (hours)	0	3.0		1.5	2		1.5	1.5	1.5

18 . . . . . . . . . . . .

=
	19	.	.	.	.	.	.	.	.	.	.	.	.

Information Sheet No. 7 Guide to using the vermicast product

Vermicast product

Vermiculture processing of compostable organics material has a number of benefits. Primarily, valuable resources that would otherwise be disposed of in landfill are processed into a beneficial end product – vermicast (Plate 1).

Vermicast is the ‘soil-like’ material produced from compostable organic

materials	processed		through
vermiculture technology.
The vermicast product		is	usually
classed as a soil conditioner.
Uses

Vermicast produced on-site is a valuable organic product that can be used to maintain the landscaped environment of an organisation.

In this way, the treatment of compostable organics in a vermiculture unit not only reduces waste to landfill (and reduces waste disposal costs) but also produces a valuable soil conditioner for use on-site.

Vermicast can be used in a variety of applications. These include:

�� a component in potting mix;

�� as a soil conditioner; and

�� to produce vermiculture liquid.

Details for the uses of these various products are given below.

Vermicast should be left to mature (or cure) prior to use. Note that the information provided refers to the use of mature vermicast. Information on harvesting and curing vermicast is given in Information Sheet No. 6.

Plate 1. Mature vermicast produced from food organics.

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Potting mix

A potting mix is a growing medium suitable for the establishment and development of plants in containers (Plate 2).

A potting mix is produced by blending a range of materials together to achieve the desired balance of drainage, moisture retention, aeration and nutrients.

Vermicast can be used as a minor component in potting mixes. The addition rate to potting mixes should not exceed 30% (by volume), as this will reduce the level of air-filled porosity in the mix.

The addition of vermicast to potting mixes can help to retain water and can supply plant nutrients and improve plant growth (Atiyeh et al., 1999).

A suggested potting mix blend (by volume) is given below:

�� 25 % vermicast – for nutrients;

�� 75% coarse sand – for drainage.

Soil conditioner

Vermicast can be used as a soil conditioner by mixing the product into soils to improve soil condition

Plate 2. Example of a general potting mix.

and plant growth.

Soil conditioners, such as vermicast, are usually incorporated into bare soil containing no plants. Seeds, seedlings, or established plants are usually planted after the soil conditioner has been applied (Recycled Organics Unit, 2001a).

In small areas, such as domestic gardens, soil conditioners can be dug into soil with a garden fork or spade.

The rate of vermicast application depends on maturity.

For fresh (immature) vermicast that has not been cured, the rate of application to soil depends upon the length of time to planting. If seeds, seedlings or established plants are to be planted within a couple of days from the incorporation of the vermicast, rates should not exceed 20 L/m² (layer not exceeding 20 mm depth).

If planting is to proceed at least two weeks after application, the application rate can be up to 50 L/m² (layer not exceeding 50 mm depth) though this will depend on application. At greater application rates, oxygen availability to plants will be reduced and may impair plant growth or result in plant death.

For mature vermicast, the rate of application can be up to 150 L/m² (150 mm in depth). At greater rates, oxygen availability to plants will reduce and may impair plant growth. Planting can proceed directly after incorporation of mature vermicast.

Vermiculture liquid

Vermiculture liquid is a water based liquid extracted from vermicast that can contain varying levels of plant nutrients.

This liquid is suitable for adding to soil surfaces and/or onto plants as a foliar spray.

Definitions*

Compostable organics

Compostable organics is a generic term for all organic materials that are appropriate for collection and use as feedstocks for composting or in related biological treatment systems (e.g. anaerobic digestion). Compostable organics is defined by its material components: residual food organics; garden organics; wood and timber; biosolids, and agricultural organics.

Vermicast

Solid organic material resulting from the biological transformation of compostable organic materials in a controlled vermiculture process.

Soil conditioner

Any composted or pasteurised organic material that is suitable for addition to soils. This term also includes ‘soil amendment’, ‘soil additive’, ‘soil improver’ and similar terms, but excludes polymers which do not biodegrade, such as plastics, rubber and coatings. Soil conditioners may be either ‘composted soil conditioners’ or ‘pasteurised soil conditioners’. Soil conditioner has not more than 15% by mass of particles with a maximum size above 15 mm.

Leachate

Liquid released by, or water that has percolated through, waste or recovered materials, and that contains dissolved and/or suspended substances and/or solids and/or gases.

Pasteurisation

The process whereby organic materials are treated to kill plant and animal pathogens and weed propagules.

Pathogens

Microorganisms capable of producing disease or infection in plants or animals. Pathogens can be killed by heat produced during thermophilic composting.

*Recycled Organics Unit (2001c)

2 . . . . . . . . . . . .

Vermiculture liquids can be produced in two ways:

�� worm-bed leachate; and

�� aqueous vermicast extracts.

Worm-bed leachate is the leachate produced from the base of a vermiculture unit. The leachate is collected and can be applied to plants or soil as a fertiliser, however, it should be noted that pathogens could be present in this vermiculture liquid.

The production of worm-bed leachate is not recommended by the Recycled Organics Unit as it tends to be a result of unsuitable moisture contents within the feedstock or bedding material. If excessive volumes of worm-bed leachate are produced, management procedures should be implemented to rectify the problem (Information Sheet No. 6).

Aqueous vermicast extracts are matured vermicast products that have been soaked/steeped in water and have had their solids strained off to produce a liquid product.

A suggested method for making aqueous vermicast extracts is given below (Murphy, 1993):

1. Mix pure vermicast with water at

Plate 3. Collecting worm-bed leachate.

a ratio of 1:20 (by weight).

1. Shake/stir thoroughly and allow to soak for twenty four hours.
2. Allow the solids to settle and drain off liquid.
3. Depending upon application method, it may be desirable to strain the liquid prior to use.

Application rates are difficult to specify due to variability in vermiculture liquid product quality and due to the absence of product standards. However, in most cases, these products need to be diluted with water before they are applied to soils and/or plants.

Vermiculture liquids usually contain a solution of organic and inorganic nutrients and a large number of organisms including bacteria and fungi.

Vermiculture liquids are also known as vermi-liquids, vermiculture liquid extracts, liquid vermicasts, liquefied vermicast, vermicast liquid teas and a number of other commercial brand names.

Benefits

Vermicast has beneficial properties when incorporated into soil. These include:

�� Reduced soil erosion, particularly in areas with exposed soils;

�� Increased water retention in the upper soil profile, thereby reducing the frequency of watering to maintain plant growth;

�� Release of nutrients for plant growth, thus reducing the need for chemical fertilisers (Vasanthi and Kumaraswamy, 1999);

�� Improved plant growth (Atiyeh et al., 2000); and

�� Suppression of soil borne plant diseases (Kannangara et al. 2000), thereby reducing fungicide and/or bacteriocide requirements.

It has also been suggested that vermicast have disease suppression qualities. The extent to which these products provide such benefits, however, vary with different methods of production and feedstock mixtures used (Kannangara et al., 2000).

Risks

A number of problems can occur with the use of vermicast. This is because vermicast, unlike other soil conditioners such as composts, do not undergo pasteurisation.

Effective pasteurisation results from the aerobic (high oxygen) and thermophilic (high temperatures of >55 ºC) processing of organic materials. This process destroys weeds, seeds and plant/animal pathogens that may have been present in the original organic materials.

However, the risks associated with materials that have not undergone pasteurisation can be avoided of the product complies with the Australian Standard AS 4454 (Draft) (2001).

More information

More details on using vermicast and other recycled organics products can be found in “How to Use Recycled Organics Products – A guide on the proper use of recycled organics products” (Recycled Organics Unit, 2001a).

For more information on the benefits and avoiding risks associated with inappropriate use of vermicast, see the “Buyers Guide for Recycled Organics Products” (Recycled Organics Unit, 2001c).

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Appendix No. 1 Ancillary equipment requirements

Equipment requirements

Reliable management of compostable materials requires effective monitoring and management procedures.

This Appendix identifies a range of equipment that may be useful for your organics management system. Such equipment may be required for establishing and implementing a system, for preparing feedstock, monitoring system performance, maintaining a healthy system, and for safe and efficient handling of materials.

The use of each item of equipment is listed as well as potential suppliers. Contact details for the suppliers are also given.

Process control plan

The equipment required is listed according to the generic process control stages in an organic management system (Figure 1).

These steps can be grouped into a number of categories:

1. Establishing a separate organics collection system – handling and collection of compostable organic material produced on-site.
2. Feedstock preparation – receival of compostable materials, size-reduction, mixing of materials into feedstocks, and storage of bulking agents.
3. Organics processing – loading/ applying feedstock into processing unit, management and monitoring procedures of the unit.

Plate 1. Example of some maintenance equipment required for a successful on-site vermiculture system.

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. . . . . . . . . . . .

Equipment required for feedstock preparation

This category includes size reduction of organic materials and mixing of materials to make a suitable feedstock for composting/vermiculture processing.

See the section on ‘Supplier details’ in this Appendix for locations and contact details of appropriate suppliers.

Buckets, gloves, apron, scoops

See previous section

Mixing/size reduction tub and spade

Use:	Large	tub (320 L,	model	no.	Supplier:		Reflex	and other	plastics
M322) and spade are suitable for size					suppliers or Hardware stores
reduction of most categories of food organics and for mixing materials to					Price:	$211.20 (320 L) tub
form feedstock.						$25.00 spade

Size reduction equipment

Use:

Rotary-shear shredder used for

Supplier:

Brentwood Shredders

and size-reduction of

high volume raw

Recycling Systems or other machinery feedstock

components and

bulking

suppliers agents.

For

many C&I

sector

Price:

Depends on size of shredder applications, a large tub and spade may be most suitable (see above).

Storage bins

Use: Mobile garbage bins (240 L) are

Supplier:

Reflex, Sulo

and

other suitable

for

storing size-reduced

plastics suppliers cardboard or paper bulking agents.

Price:

$88.00 (240 L)

Plastic shovel

Use: Food grade, “deep bucket” spade

Supplier:

Hardware

stores

(eg. for mixing raw components and bulking

Hardwarehouse, Blackwoods or similar) agent to achieve a suitable feedstock for

Price:

$25.00

vermiculture processing. Mouth width of shovel fits into 25 L buckets.

Hose and trolley

Use: Site clean-up after preparation of

Supplier:

Hardware

stores

(eg. feedstock including rinsing down work

Hardwarehouse, Blackwoods or similar) area, buckets and tubs.

Price:

$30.00 hose $50.00 trolley

Brooms and dustpan

Use: Site clean-up after preparation of

Supplier:

Hardware

stores

(eg. feedstock.

Hardwarehouse, Blackwoods or similar)

Price:

$10.00 broom $5.00 dustpan

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Appendix No. 2 Vermicast product standard

Vermicast product standard

The processing of compostable organics material in vermiculture technology minimises waste to landfill and produces vermicast as a beneficial end product.

Vermicast is a valuable soil conditioner and is useful for landscaping and improving gardens. It is recommended by this Best Practice Guideline to use the vermicast product on-site.

However, if vermicast was to be sold commercially, it is useful to be aware of the relevant vermicast product standards. Managing the vermiculture process will support the production of vermicast that complies with the standard, and therefore valued by the market. Compliance with this standard will also minimise risks of a poor quality product being sold to buyers.

An industry standard for vermicast exists and at time of printing, this vermicast industry standard has been included in the 2001 draft update of the Australian Standard AS 4454 for composts, soil conditioners and mulches.

Until this standard is released, however, as vermicast can be considered to be a soil conditioner, manufacturers should aim for compliance against the current standard, AS 4454 (1999).

It should be noted that most C&I sector establishments will use vermiculture as an on-site waste management tool for recycling organics on-site and not as a tool to produce vermicast commercially. As such, compliance with AS 4454 (1999) is only recommended if the vermicast is to be sold commercially.

Australian Standard AS 4454 (1999)

The Australian Standard AS 4454 (1999) contains guidelines to provide manufacturers, local government bodies, consumers and growers with:

�� Minimum requirements for the physical, chemical and

Plate 1. A soil conditioner certified under AS 4454 (1999) for composts, soil conditioners and mulches. This product is suitable for incorporating into soil to improve soil conditions and plant growth.

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biological properties of composts, soil conditioners and mulches; and

�� Labelling and marketing requirements, in order to facilitate beneficial processing and use of organic materials with minimal adverse impact on the environment and public health.

The standard also sets out best practice guidelines to enable producers to consistently produce quality composts, soil conditioners and mulches (Recycled Organics Unit, 2001a).

Why is an industry standard needed?

The production of vermicast from vermiculture processing of food organics and garden organics requires best practice guidelines to ensure the vermicast product is not contaminated with animal pathogens (including human), plant pathogens and plant propagules (weeds). An industry standard provides generic best practice guidelines that apply to all vermiculture units and provide the basis for market confidence in vermicast quality.

Figure 1. Certified product logo demonstrating compliance to a recognised product standard.

Some products made from recycled organics that are commercially available do not live up to consumer’s expectations. These products can be variable in quality and damaging to plants when applied as a compost, soil conditioner or mulch.

Benefits of compliance with an Australian Standard

When purchasing a recycled organic product, consumers can be assured the product is of a high quality if it is certified against the Australian standard. Also, manufacturers can ensure consumers are receiving a quality product by testing the product according to this standard prior to sale.

Australian standard certification allows the manufacturer to label the product with the recognised Australian standard ‘five ticks’ logo (Figure 1). To achieve this certification, the manufacturer must comply with criteria defined by the relevant standard.

Products certified against an Australian standard are easily recognisable in the market place and provide assurance of quality. Consequently, consumers can buy a certified product with confidence.

How to comply with the vermicast standard

Quality vermicast is best achieved by effectively controlling the manufacture of the vermicast product. Implementing a management system based on quality management system principles, and best practice vermiculture management principles, will provide an optimum outcome.

A quality management system is the implementation of operational procedures that support the manufacture and supply of a consistently high quality product. Best practice principles are used to

Definitions*

Compostable organics

Compostable organics is a generic term for all organic materials that are appropriate for collection and use as feedstocks for composting or in related biological treatment systems (e.g. anaerobic digestion). Compostable organics is defined by its material components: residual food organics; garden organics; wood and timber; biosolids, and agricultural organics.

Vermicast

Solid organic material resulting from the biological transformation of compostable organic materials in a controlled vermiculture process.

Soil conditioner

Any composted or pasteurised organic material that is suitable for adding to soils. This term also includes ‘soil amendment’, ‘soil additive’, ‘soil improver’ and similar terms, but excludes polymers which do not biodegrade, such as plastics, rubber and coatings. Soil conditioners may be either ‘composted soil conditioners’ or ‘pasteurised soil conditioners’. Soil conditioner has not more than 15% by mass of particles with a maximum size above 15 mm.

Compost

An organic product that has undergone controlled aerobic and thermophilic biological transformation to achieve pasteurisation and a specified level of maturity. Compost is suitable for the use as soil conditioner or mulch and can improve soil structure, water retention, aeration, erosion control, and other soil properties.

Mulch

Any pasteurised organic product (excluding polymers which do not degrade such as plastics, rubber and coatings) that is suitable for placing on soil surfaces. Mulch has at least 70% by mass of its particles with a maximum size of greater than 15 mm.

Best practice

For any area of waste management, this represents the current 'state-of-the-art' in achieving particular goals. Best Practice is dynamic and subject to continual review and improvement.

Continued page 3

2 . . . . . . . . . . . .

develop a set of efficient and consistent operational procedures that will maintain product quality and minimise the impact of vermiculture technology on the environment. This best practice guideline, and the vermicast industry product standard, will assist in producing a quality vermicast product.

In order to comply with the vermicast industry standard, the vermicast product must exhibit a number of physical and chemical requirements. These requirements are given in Table 1.

If claiming certification against the standard, compliance must be demonstrated periodically by testing by an independent laboratory.

What products are covered in AS 4454 (Draft) (2001)?

At the time of printing, the standard provides quality guidelines for three major categories of product: pasteurised products, composted products and vermicast.

Products defined in this standard are manufactured by the controlled microbial transformation of organic materials.

Vermiculture derived products can be subject to pre-processing or postprocessing pasteurisation. Preprocessing pasteurisation involves pasteurising the feedstock material before vermiculture processing. This eradicates pathogens and weed seeds. Post-processing pasteurisation involves pasteurising the finished vermicast product, however, this also results in the destruction of the beneficial microorganisms present in the vermicast.

Studies have shown that human and plant pathogens are reduced through processing under mesophilic conditions in vermiculture units (Brown and Mitchell, 1981; Amaravadi et al., 1990; Pederson and Henrikson, 1993).

3 . . .

Continued from page 2

Food organics Pathogen

The Food Organics material description is Microorganisms capable of producing disease defined by its component materials, which or infection in plants or animals. Pathogens include: fruit and vegetable material; meat and can be killed by heat produced during poultry; fats and oils, seafood (including thermophilic composting. shellfish, excluding oyster shells); recalcitrants (large bones >15mm diameter, oyster shells, Quality management system coconut shells etc.); dairy (solid and liquid); Management system to direct and control an bread, pastries and flours (including rice and organisation with regard to quality. corn flours); food soiled paper products (hand towels, butter wrap etc.); and biodegradeables Pasteurised product (cutlery, bags, polymers). Such materials may A process whereby organic materials are be derived from domestic or commercial and treated to kill plant and animal pathogens and industrial sources. The definition does not plant propagules. Pasteurisation can be include grease trap waste. Food organics is one achieved by the controlled biological of the primary components of the compostable transformation of organic materials under organics stream. aerobic and thermophilic conditions such that

the whole mass of constantly moist material is Garden organics subjected to at least 3 consecutive days to a The Garden Organics material description is minimum temperature of 55°C (or by defined by its component materials including: equivalent process). putrescible garden organics (grass clippings); non-woody garden organics; woody garden Pasteurisation organics; trees and limbs; stumps and The process whereby organic materials are rootballs. Such materials may be derived from treated to kill plant and animal pathogens and domestic, Construction and Demolition and weed propagules. Commercial and Industrial sources. Garden Organics is one of the primary components of Mesophilic the compostable organics stream. A temperature range of 20 – 45 ^oC.

*Recycled Organics Unit (2000b)

AS 4454 (Draft) (2001) requires that if pre-or post-processing pasteurisation is not performed, analytical testing must be performed to confirm the absence of plant propagules and problematic human pathogens (including E. coli and Salmonella).

In a well-managed system, vermicast produced from materials containing human pathogens (such as meat etc.) can undergo an adequate level of sanitation, however, testing is recommended and pre-or postprocessing pasteurisation will significantly decrease the risk of transmitting pathogens.

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Table 1. Physical and chemical requirements for vermicast (Standards Australia AS 4454, 2001 Revised draft).

Characteristic and unit of measurement Requirement

pH 5.0 – 7.5 pH units If pH > 7.5 determine total CaCO3

Electrical conductivity No limit dS/m

Phosphorous, soluble ≤ 5

For products which claim to be for phosphorus-sensitive plants mg/L in extract No requirement otherwise

Phosphorous, total ≤ 0.1

For products which claim to be for phosphorous-sensitive plants % dry mass No requirements otherwise

Ammonium-N No requirement mg/L in extract

Ammonium-N plus nitrogen-N >100 mg/L in extract If a contribution to plant nutrition is claimed

Nitrogen, total ≥ 0.8 % dry matter If a contribution to plant nutrition is claimed

Organic matter content ≥ 25 % dry matter

Boron¹ < 200 mg/kg dry mass Products with a total B of < 100 can have unrestricted use

Sodium < 1 or at least 7.5 moles calcium plus magnesium for each mole of % dry mass sodium in the dry matter

Wettability < 7 For the < 16 ± 1 mm fraction. minutes If <5% of the product is <16 mm, the wettability test does not apply.

Toxicity index ≥ 20 for all products except those labelled as manure, for which EC % criteria are more appropriate

PARTICLE SIZE GRADING Maximum size ≤ 16 millimetre Tolerance Not more than 20% by mass in the shortest dimension to be retained by

% mass the sieve

Total CaCO3 equivalent To be determined and stated if pH > 7.5 % dry matter

Chemical contaminants (includes heavy metals) To comply with current national guidelines for unrestricted use

Organic contaminants To comply with current national guidelines for unrestricted use

Moisture content Minimum 25

Maximum = % organic matter (OM) + 6 if OM > 40% % Maximum = % organic matter + 10 if OM < 40%

CONTAMINANTS Glass, metal and rigid plastics > 2 mm ≤ 0.5 Plastics – light, flexible or film > 5 mm ≤ 0.05 Stones and lumps of clay 5 mm ≤ 5

Suppliers and their customers are advised to agree upon an acceptable maximum level of visual contamination by light weight plastic (5% by _{% dry matter (w/w)} volume has been suggested but there may be reason to differ)

Self heating No requirement ^oC

Vermicast sieve test 90% passing through the 1.8 mm sieve apertures

Plant propgules Nil

¹ Note: testing for B will generally only be necessary for products that are based on seaweed, seagrass or unseparated municipal solid wastes that have a component of cardboard packaging

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Summary

Compliance with the vermiculture product standard Australian Standard AS 4454 (1999) for composts, soil conditioners and mulches, will increase the perceived quality and commercial value of a product.

The treatment of compostable organic materials via vermiculture processing on-site produces an end product of vermicast. This product can be sold commercially however compliance with the relevant product standard involves pre-or postprocessing pasteurisation and/or product testing. These requirements will increase the cost of the vermiculture process, however, such costs may be returned through the sale of a quality vermicast product.

Vermicast is best used on-site to improve the landscaped environment of the organisation. This use of the vermicast product therefore avoids the need for equivalent landscape products that would otherwise be purchased at commercial rates.

Vermicast is a valuable end product that can improve the commercial viability of on-site vermiculture treatment of compostable organic materials. However, most C&I sector establishments will find greater benefit by focusing on managing the system to reduce the amount of waste sent to landfill.

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Appendix No. 3 Signage

Standard signage

This Appendix contains example signage for use in Commercial and Industrial (C&I) sector organisations where source separate, compostable organics collection systems have been installed.

The signage can be used in areas where compostable organic material is to be collected – for example, food preparation and consumption areas (Plate 1).

Signage clearly informs people of what materials should be placed in each type of bin, and what should not.

All collection containers should be labelled with the same markings (and ideally all be the one colour) so they are readily distinguished from bins that are used for other purposes.

Materials that are not compostable (eg. metal, plastic, glass) are considered as contaminants and can cause a range of inefficiencies and problems later on.

A standard range of bin labels have been developed that comprise consistent colours and symbols to represent waste, recyclables and compostable organic materials (Plate 2).

These colours and symbols are often seen on mobile garbage bins used in public places.

Plate 1. Compostable organics bin and Plate 2. Standard colour collection bin site specific sign in a commercial and label kitchen

The ROU is the NSW centre for organic resource management, information, research & development, demonstration and training

Easy identification and clearly from non-compostable (eg. plastic) �� pre-consumer fruit, vegetables, distinguishable containers are key single portion items like sugar or bread and meat from food elements in a successful recycling jam. preparation activities; system.

A small hotel that provides meals of �� post-consumer plate scrapings of Examples of standard bin labels are breakfast, lunch and dinner has fruit, vegetables, meat, bread and contained at the end of this Appendix implemented a source separate soiled paper serviettes; and details of suppliers are also collection system for compostable provided. organic materials. The material could ^{�� paper packaging materials from}

be processed on-site via composting ^{single serve items such as} It may be more useful, however, to _{or vermiculture, or could be collected} condiments, sugar and tea bags; develop signage that is relevant to the _{for composting at a centralised}

^{specific types of materials produced} facility. In this example, the material ^{�� coffee grinds;} from your organisation (see Plate 1). _{is being processed on-site in a �� newspapers and packaging boxes}

_Example ^{vermiculture unit.} such as cereal boxes; and

_{As mentioned, information signage} Food is prepared on-site and plate

�� flowers from table displays. _{tends to be more effective if it is} scrapings are cleared by kitchen staff.

directly relevant to your organisation. ^{“Compostable organic material only” General rubbish signs for this hotel} bins are placed in the kitchen area should directly compliment “organics Generic information sign examples and are emptied regularly. A only” information signs by targeting are shown below, however, particular previous audit identified the the key materials so that staff can attention should be given to following range of organic materials clearly identify which items go into distinguish compostable (eg. paper) produced on-site: which bin.

Figure 1. Example signage for a small hotel based on an audit of organics produced on-site. Identifying key organic fractions for vermiculture processing will educate staff and minimise contamination levels.

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Example signs are shown in Figures For example, contamination of label combination to 1 and 2 for compostable organic organic material with broken glass differentiate between “organics materials and general garbage will pose a safety risk to staff only” bins, paper bins, general respectively. handling the material and preparing recyclables and also garbage

the feedstock, and harvesting and bins. Details for suppliers of ^{How to use signage} using the compost/vermicast product. durable stickers are given at the effectively end of this section.

The potential for contamination, and ^{Effective signage for separate} the difficulties associated with �� Combining words, colour and ^{collection of compostable organic} sorting through contaminated organic pictures – a combination of^{materials and bulking agents will} material, leads to the necessity of words, colour and pictures reduce contamination, avoiding risks _{having clear and effective signage.}

should be used to differentiate ^{associated with post collection} between different types of bins. ^sorting. Some suggestions on using signage effectively are given below: �� Accessibility – place the bins in areas that are easily accessible �� Consistent bin colour – using a

consistent colour and bin shape

will increase the effectiveness of

and are efficient to use. Make garbage bins and “organics only” bins equally accessible so ^{collection bins.} as not to increase the amount of work staff need to do in order to

�� Consistent bin labels – bin labels

place materials in the correct

must also be consistent. Use

bin.

standard designs as staff will ^{recognise the bin colours and} �� Inform clearly – use information

signs to clearly communicate

which items go in which bins.

Figure 2. Example signage for a small hotel based on an audit of organics produced on-site. Identifying key general waste items for landfill disposal will educate staff _{�� Location – try to locate the} and minimise contamination levels for collection of residual organics.

“organics only” bins adjacent to a general garbage bin, other wise mixed materials are likely to go into both.

Garbage

�� Ensure the different bins are equally user friendly/efficient – ^{large bones} if the garbage bin has a lid that ^{(> 10-15 mm)} needs to be removed and the adjacent organics bin does not, _{disposable styrofoam} you can guarantee that more general rubbish (contamination)

cups and lids

will be disposed of in the organics bin.

plastic packaging material

plastic teaspoons

cling wrap

food soiled aluminium foil

general waste items

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Generic signs

A number of generic bin labels that can be photocopied are included at the end of this Appendix.

It is recommended, however, that site specific information signs be produced such as those given in the example above. If this is not possible, these generic signs may help.

The signs provided are applicable to:

�� compostable organics

�� food organics;

�� cardboard;

�� paper and cardboard; and

Definitions*

Source separation

Physical sorting of the waste stream into its components at the point of generation.

Compostable organics

Compostable organics is a generic term for all organic materials that are appropriate for collection and use as feedstocks for composting or in related biological treatment systems (e.g. anaerobic digestion). Compostable organics is defined by its material components: residual food organics; garden organics; wood and timber; biosolids, and agricultural organics.

Composting

The process whereby organic materials are pasteurised and microbially transferred under aerobic and thermophilic conditions for a period of not less than six weeks. By definition, it is a process that must by carried out under controlled conditions yielding mature products that do not contain any weed seeds or pathogens.

Vermiculture

System of stabilising organic materials under controlled conditions by specific worm species and microorganisms under mesophilic temperatures. Commercial vermiculture systems include: windrows or beds; stackable trays; batch-flow containers, and continuous flow containers.

�� garbage.

Generic signs for bins are available from “Associate Labels” in Sydney.

Ph: (02) 9905 6522

PO Box 238, Brookvale, Sydney, 2100

For other suppliers look under “labels” in the Yellow Pages.

Contamination (composting)

Contaminants within this context include physical inorganic materials (metals, glass etc.), non-biodegradable organic materials (plastics), chemical compounds and/or biological agents that can have a detrimental impact on the quality of any recycled organic products manufactured from source separated compostable organic materials.

Bulking agent

An ingredient in a mixture of composting raw materials included to improve the structure and porosity of the mix. Bulking agents are usually rigid and dry and often have large particles (for example, straw or wood chips). The terms “bulking agent” and “amendment” are often used interchangeably. See also composting amendment.

Feedstock

Organic materials used for composting or related biological treatment systems. Different feedstocks have different nutrient concentrations, moisture, structure and contamination levels (physical, chemical and biological).

Compost

An organic product that has undergone controlled aerobic and thermophilic biological transformation to achieve pasteurisation and a specified level of maturity. Compost is suitable for the use as soil conditioner or mulch and can improve soil structure, water retention, aeration, erosion control, and other soil properties.

Vermicast

Solid organic material resulting from the biological transformation of compostable organic materials in a controlled vermiculture process.

Food organics

The Food Organics material description is defined by its component materials, which include: fruit and vegetable material; meat and poultry; fats and oils, seafood (including shellfish, excluding oyster shells); recalcitrants (large bones >15mm diameter, oyster shells, coconut shells etc.); dairy (solid and liquid); bread, pastries and flours (including rice and corn flours); food soiled paper products (hand towels, butter wrap etc.); and biodegradeables (cutlery, bags, polymers). Such materials may be derived from domestic or commercial and industrial sources. The definition does not include grease trap waste. Food organics is one of the primary components of the compostable organics stream.

*Recycled Organics Unit (2001)

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Appendix No. 4

Research Case Studies – Vermiculture processing of compostable organics

Vermiculture processing of compostable organics

The Recycled Organics Unit has conducted a series of research projects on the processing of organic materials using vermiculture technology.

The purpose of the research was to determine what categories of organic materials are capable of being processed via in-vessel vermiculture technology, and to quantify the sustainable processing capacity of vermiculture technology for these materials (Recycled Organics Unit, 2000).

This research program involved a literature review that provided

information		for	the	subsequent
analytical trials.			The	vermiculture
units	used	in	the	trials	were

designed to closely simulate conditions experienced in vertical loading, continuous-flow in-vessel vermiculture units.

A number of reports have documented the feasibility of using vermiculture technology for the treatment of compostable organics material. However, extremely limited quantitative information has been available on the processing of food organics.

The research performed by the Recycled Organics Unit primarily focussed on the vermiculture processing of food organics, and to a lesser extent, on complementary materials including cardboard, lawn clippings and non-woody garden organics.

Food organics is defined by its component materials as detailed in the following table:

Material

Fruit and vegetable material Bread, pastries and flours Meat and poultry Fats and oils Seafood

Food soiled paper products Biodegradeables

Dairy Recalcitrants

Detail

Including rice and corn flours

Including shellfish, excluding oyster shells

Hand towels, butter wrap etc. Cutlery, bags, polymers Solid and liquid Large bones, oyster shell, coconut shells etc.

These types of materials tend to dominate the metropolitan solid waste stream. Food organics in particular tend to dominate the commercial and industrial sector waste stream, and the diversion of this material to processing for beneficial land applications offers a range of environmental benefits.

The case studies of trials performed by the Recycled Organics Unit detailed in this Appendix include:

1. Feedstock acceptance trial
2. Bench-scale vermiculture trial

The ROU is the NSW centre for organic resource management, information, research & development, demonstration and training

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Definitions*

Processing capacity

The maximum amount (mass or volume) of feedstock that can be added to a processing technology (e.g. composting technology) per unit time (e.g. per week) without causing system failure. System failure is evident when the processing technology produces problematic environmental emissions and/or declines in processing efficiency and/or produces product of unacceptable quality.

In-vessel

A containerised unit in which vermiculture, compost or anaerobic digestion-based processes are performed. Containers vary in size, configuration, degree of automation and level of process control. In-vessel systems are often used for treatment of putrescible organics in populated areas as they have minimal or no significant impact on the environment (eg. through the generation of odour, leachate or attraction of pests or vermin).

Compostable organics

Compostable organics is a generic term for all organic materials that are appropriate for collection and use as feedstocks for composting or in related biological treatment systems (e.g. anaerobic digestion). Compostable organics is defined by its material components: residual food organics; garden organics; wood and timber; biosolids, and agricultural organics.

Food organics

The Food Organics material description is defined by its component materials, which include: fruit and vegetable material; meat and poultry; fats and oils, seafood (including shellfish, excluding oyster shells); recalcitrants (large bones >15mm diameter, oyster shells, coconut shells etc.); dairy (solid and liquid); bread, pastries and flours (including rice and corn flours); food soiled paper products (hand towels, butter wrap etc.); and biodegradeables (cutlery, bags, polymers). Such materials may be derived from domestic or commercial and industrial sources. The definition does not include grease trap waste. Food organics is one of the primary components of the compostable organics stream.

Agricultural organics

Any residual organic materials produced as by-products of agricultural and forestry operations, including: weeds (woody and non-woody); animals (processing residuals, stock mortalities, pests), crop residuals (woody and non-woody), and manures.

Biosolids

Organic solids or semi-solids produced by municipal sewage treatment processes. Solids become biosolids when they come out of an anaerobic digester or other treatment process and can be beneficially used. Until such solids are suitable for beneficial use they are defined as waste-water solids. The solids content in biosolids should be equal to or greater than 0.5% weight by volume (w/v). Biosolids are commonly co-composted with garden organics and/or residual wood and timber to produce a range of recycled organics products.

Garden organics

The Garden Organics material description is defined by its component materials including: putrescible garden organics (grass clippings); non-woody garden organics; woody garden organics; trees and limbs; stumps and rootballs. Such materials may be derived from domestic, Construction and Demolition and Commercial and Industrial sources. Garden Organics is one of the primary components of the compostable organics stream.

Anaerobic

In the absence of oxygen, or not requiring oxygen.

Bulking agent

An ingredient in a mixture of composting raw materials included to improve the structure and porosity of the mix. Bulking agents are usually rigid and dry and often have large particles (for example, straw or wood chips). The terms “bulking agent” and “amendment” are often used interchangeably. See also composting amendment.

Feedstock

Organic materials used for composting or related biological treatment systems. Different feedstocks have different nutrient concentrations, moisture, structure and contamination levels (physical, chemical and biological).

Carbon to nitrogen (C:N) ratio

The ratio of the weight of organic carbon (C) to that of total nitrogen (N) in an organic material.

*Recycled Organics Unit (2001)

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