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Recycled Organics Unit Building B11b The University of New South Wales UNSW Sydney NSW 2052 Australia

Internet: http://www.recycledorganics.com

Copyright Đ Recycled Organics Unit 2002. First Published 2002.

The Recycled Organics Unit (ROU) has been established as an independent technical unit at The University of New South Wales to provide a NSW centre for organic resource management, information, research and development, development and training.

This document is and shall remain the property of ROU, The University of New South Wales. The information contained in this document is provided by ROU in good faith but users should be aware that ROU is not responsible or liable for its use or application. The content is for information only. It should not be considered as any advice, warranty, or recommendation to any individual person or situation.

Authors: Amanda Ferris, Dr Mark Jackson and Angus Campbell

National Library of Australia Cataloguing-in-Publication entry:

Printed by Recycled Organics Unit, The University of New South Wales.

Quality assurance : Document history

Revision number Revised by Date
1 AF 13/09/01
2 MJ 18/09/01
3 AC 08/11/01
4 AF 21/11/01
6 SSWB 10/12/01
7 Peer review (1) (Vermitech) 14/12/01
8 Peer review (2) (David Murphy) 03/12/01
9 Peer review (3) (AWGAVI) 12/12/01
FINAL AF/MJ 09/01/02

Preface to the Best Practice Guideline to Managing On-Site Vermiculture Technologies Information Sheets

The Best Practice Guideline to Managing On-Site Vermiculture Technologies series of Information Sheets have been produced to support the continuing development of the Recycled Organics industry in New South Wales and to provide best practice guidelines for the on-site treatment of compostable organic materials produced by the commercial and industrial (C&I) sector.

Treatment of compostable organics produced on-site by the C&I sector using vermiculture technology represents a potentially viable way of managing these materials. The production of vermicast also provides a product that may be used to maintain the landscaped environment.

The establishment and management of an on-site vermiculture unit can result in some uncertainties in terms of the performance capabilities of such units and the management practices required to sustain these capabilities. Failure can occur within vermiculture units due to a number of reasons that usually relate to an absence of information and management within the organisation.

Efficient management and monitoring of vermiculture units is necessary to maintain an effective processing system and to ensure adequate system performance without any adverse affects on the environment.

To ensure a vermiculture unit is efficient and effective, it must be installed at an adequate scale to meet the requirements of the organisation. The development of an on-site organics management system should also result in realistic expectations as to the performance capabilities of the system. A level of commitment from both management and staff is required to ensure operational success.

This guide to best practice management will support the appropriate and sustainable application of on-site vermiculture technology in the C&I sector. Information has been provided that will inform the vermiculture industry, the waste management industry and relevant C&I sector enterprises and institutions on the capabilities, management requirements and appropriate application of on-site vermiculture technology.

These Information Sheets have been developed to complement existing information resources and to provide an easy-to-read account of how to establish and manage an on-site, mid-scale vermiculture unit for the C&I sector. On-site, mid scale organics management systems are capable of processing between 20 and 250 kg of compostable organics per day. The guide gives practical information as to the development of such a system including feedstock preparation, monitoring and maintenance procedures and use of the vermicast end product.

Amanda Ferris, Mark Jackson and Angus Campbell

Recycled Organics Unit

The University of New South Wales.

Sydney, January 2002.

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

1. Information Sheets in “Best Practice Guideline to Managing On-Site Vermiculture Technology

This package contains a collection of seven Information Sheets and four Appendices:

  • Information Sheet No. 1:
  • Information Sheet No. 2:
  • Information Sheet No. 3:
  • Information Sheet No. 4:
  • Information Sheet No. 5:
  • Information Sheet No. 6:
  • Information Sheet No. 7:
  • Appendix No. 1:
  • Appendix No. 2:
  • Appendix No. 3:
  • Appendix No. 4:

Introduction to establishing and managing an on-site vermiculture unit. How much compostable material is produced? Can vermiculture work for you? Guide to feedstock preparation and determining what size vermiculture unit is required. Guide to installing a vermiculture unit. Management and maintenance of a vermiculture unit. Guide to using the vermicast product. Ancillary equipment requirements. Vermicast product standard. Signage. Research Case Studies – Vermiculture processing of compostable organics.

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

2. Who should read the Information Sheets? The package of Information Sheets has been developed to meet the needs of the developing vermiculture industry. It is suitable for stakeholders in the RO sector who wish to gain a better knowledge of the vermiculture industry, key points for establishing an on-site vermiculture unit, industry best practices, and product standards that significantly influence product quality.

More specifically, the package of Information Sheets have been developed for:

  • commercial and industrial sector organisations;
  • vermiculture industry consultants;
  • commercial and industrial sector consultants;
  • waste educators;
  • waste managers;
  • prospective RO processors; and
  • local council waste management officers.
  1. Terminology Terms used throughout this package of Information Sheets have been officially adopted by the NSW Waste Boards in July 2000 in the form of the RO Dictionary and Thesaurus: Standard terminology for the New South Wales recycled organics industry, produced by the Recycled Organics Unit. This document is freely downloadable from http://www.rolibrary.com
    1. How to cite this publication This publication consists of a series of Information Sheets that are compiled into a set. When citing information from this publication, the set of Information Sheets must be cited (not individual Information Sheets), as shown below:
    2. Recycled Organics Unit (2002) Best Practice Guideline to Managing On-Site Vermiculture Technologies. Printed by the Recycled Organics Unit, The University of New South Wales, Sydney, Australia.
  2. Acknowledgements The authors would like to extend a special thank you to all members of the peer review committee who have invested their valuable time in reading and providing feedback on this package of Information Sheets. The following reviewers are graciously thanked for their contributions:

Mr. Karsten Eisenaecher, Quality Assurance Manager and Process Control Coordinator, Vermitech Pty. Ltd.

Mr. Mike Daniels, President, Australian Worm Growers Association Vermiculture Inc.

Mr. David Murphy, Author (Earthworms in Australia: A blueprint for a better environment).

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

What is vermiculture?

Vermiculture involves the stabilisation of compostable organics under controlled conditions by particular worm species.

Compostable organic materials, such as residual food organics and garden organics, are loaded into the vermiculture unit where they are ‘eaten’ by the worm population.

Worms convert the fresh materials into vermicast, a brown soil-like material that is produced after organic materials have passed through the digestive system of a worm. Vermicast is high in nutrients and can be used as a valuable soil conditioner.

A limited range of enterprise types in the commercial and industrial (C&I) sector have the potential to utilise

Information Sheet No. 1

Introduction to installing and managing anon-site vermiculture unit

vermiculture for on-site treatment of compostable organics.

The implementation of vermiculture technology requires careful planning and management to ensure it will be able to continually process organic materials with minimal impact on the surrounding environment.

This series of information sheets details best practice requirements for implementing and managing such technology.

Plate 1. Components of an organics management system for processing compostable organic materials in a vermiculture unit.

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

Components of a vermiculture unit

A vermiculture unit consists of four main components:

  1. Container – houses the bedding and worm population so they can consume organic materials loaded into the unit. The container also excludes pests and protects worms from both the elements and predators.
  2. Worm population – necessary to convert the compostable organic materials into vermicast that can be used as a soil conditioner.
  3. Bedding – a deep layer of mature vermicast is recommended as a medium for worms to live in. A greater mass of bedding reduces the variation in bedding temperature and moisture.
  4. Source of food and moisture for the worms – this is applied to the surface of the bedding.

The external and internal components of a vertical loading, continuous flow vermiculture unit are shown in Figure 2.

Basic science of vermiculture

Processing of compostable organic materials via vermiculture is an aerobic (high oxygen) process performed by worms and microorganisms. The basic science of this process can be seen in Figure 3.

When organic materials are loaded into a vermiculture unit, bacteria, fungi and other microorganisms start to decompose or ‘eat’ them.

The worm population works with these microscopic organisms. Worms scavenge and eat the decomposing products (such as sugars, proteins and simple carbohydrates) released by the microorganisms and even eat the microorganisms as well!

Consequently, a well managed vermiculture unit involves the maintenance of conditions that are ideal for the survival and growth of microorganisms and worms.

Figure 2. Components of a vertical loading vermiculture unit and an internal view.

Unit lid Air vents – allows air to flow into unit Raised container – houses all worms, feedstock and bedding Metal base – allows vermicast to be harvested from base Collection tray – collects harvested vermicast and leachate

Surface applied organic material Worm population in bedding Maturing vermicast bedding Finished vermicast and leachate

Definitions*

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.

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.

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.

Vermicast

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

Continued page 4

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

Ideal environmental conditions include:

air – at least 10% oxygen (O2) present in the bedding where the worms are actively feeding (there is 21% O2 in normal air);

moisture – moisture content of the bedding material should be between 60 and 90%;

warmth – ideal bedding temperatures are between 20 and 25oC but worms will survive between 5 and 35oC;

food – such as fruit, vegetables, mixed food organics, paper, cardboard etc.;

absence of pests – insect larvae compete with the worm population and pose a public health hazard; and

protection from predators and environmental extremes.

Types of vermiculture units

A number of different types of vermiculture units are available for on-site processing of compostable organic material. These include:

Continuous flow units; Tray or stacking units;

Batching or box units; and

Windrow systems.

Details of these types of vermiculture units are given below.

Continuous flow units

Continuous flow vermiculture units consist of a raised container with a mesh floor and a breaker bar that slides across the mesh floor to agitate and allow harvesting of the vermicast. Feed is applied to the top surface of the bedding and finished vermicast is harvested from the base, allowing the continuous processing of compostable organic materials.

Continuous flow units vary in terms of engineering complexity from low technology units with manual feeding and harvesting methods, to complex technology units that comprise a fully automated and hydraulically driven continuous reactor.

Continuous flow technology is the most efficient type of on-site, mid-scale vermiculture unit and the least labour intensive. Plate 2 details some commercially available continuous flow units.

Figure 3. Process diagram for a vermiculture unit (adapted from Recycled Organics

Unit, 2001).

Compostable organic material – including carbon, chemical energy, protein and nitrogen

Mineral nutrients-including nitrogen and other elements

Water

Worms

Microorganisms

O2

heat CO2

Finished vermicast containing organic matter including carbon, chemical energy, nitrogen, protein, humus, mineral nutrients, water and microorganisms

leachate

. . . . . . . .

Continued from page 3

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.

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.

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.

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.

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.

Continued page 5

. . . .

Tray or stacking units

Tray or stacking units consist of a number of stacked trays with bedding and worms placed in the trays. Feed is applied to the top surface of the bedding and when the tray is full, the vermicast is left to mature before the entire batch (tray) is dug out manually.

Tray or stacking units can be relatively labour intensive at time of harvesting when each tray of mature vermicast needs to be removed from the unit.

Tray or stacking units are used for mid-scale vermiculture processing, however, these units are not as widely used as continuous flow units.

Batching or box units

Batching or box units are a simple and relatively popular design for small-scale (domestic) vermiculture applications. This type of unit consists of a container that houses all bedding, worms and vermicast with feed applied to the top surface. The challenge is separating worms from vermicast to enable harvesting of the vermicast product.

Batching or box vermiculture units can be relatively labour intensive at time of harvesting and hence are not as popular for mid-scale applications.

Batching or box units are cheap, and are widely used in household applications.

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