Waste management

Domestic organic waste recovery - the ecological and econimical option:


It's the right tools that change behaviour!

This page is for local government waste minimisation officers. Earthmaker Enterprises is happy to discuss specific needs and work with councils to develop integrated waste management solutions.

1. Summary


2. Approaches to organic waste minimisation


3. Tools to change behaviour


4. Incentives and costs

1. Summary


1.1 The case for composting

It is widely accepted that composting is the most environmentally responsible alternative to burying organic waste in landfills where it generates methane gas (23 x stronger than carbon dioxide) or processing it through the sewage system which consumes extra water and energy mixes it with contaminated sludge.

1.2 The case for home composting

Home composting neither consumes the energy nor generates the carbon emissions involved in transporting material to a centralised site and then processing, packaging and distributing it.

1.3 The problem with standard bins

Single bins only work if the material is regularly lifted and turned to allow oxygen into the mix. Many households can’t be bothered with this because it takes time and effort, and it mixes old and new material. Single bins are merely plastic covers for organic material piled on the ground where it rots anaerobically and becomes a smelly producer of methane gas and leachate – so it is not eco-friendly composting. Many households give up and revert to previous behaviour.

1.4 The case for aerobic composting

Aerobic composting – when oxygen is able to aerate organic waste – accelerates the process, significantly reduces greenhouse gas emissions and sequesters carbon when applied to soil.

1.5 The case for Earthmaker

The Earthmaker composter was first designed as an easy way to process domestic organic waste – “traditional three-bin composting, but gravity does the hard work!” Its patented ‘continuous cycle composting’ means new waste can be added and mature compost removed continuously. Material is held above the ground during the mixing and digesting stages. Heat in the top chamber, generated by trapping free radiant heat from the sun and the decomposition process itself, draws air up through the compost and the material loosens as it spills from shelf to shelf. These unique factors promote an aerobic process. The outcomes include:
- increased use of home composting because it is easier and faster than other options;
- reduced greenhouse gas emissions (methane) during the composting process.

1.6 The right tools change behaviour

The most effective way to change behaviour is to supply equipment that meets needs and suits lifestyles. Wheelie bins changed behaviour – people filled them up! Recycling bins are changing behaviour now. The right tool will make aerobic composting ‘inside the gate’ the preferred option. The Earthmaker is that tool.

1.7 Incentives and costs

Each local authority has different waste management issues to address. Some communities will embrace environmentally beneficial change. Others may require financial incentives.
Earthmaker Enterprises has developed strategies to gain widespread support for change.
In many cases the introduction of Earthmakers can achieve costs savings over current disposal methods. It may also be possible to earn carbon credits.
A lease-back funding model has been developed to enable local governments to purchase Earthmakers without up-front capital expenditure – monthly payments are offset by savings.

2. Approaches to organic waste processing

2.1 Landfill burial

Problems related to burying organic waste in landfills include:
- creates methane gas (23x stronger than CO2) and leachate;
- smell endured by workers and neighbours;
- danger – methane can be explosive when concentrated in an enclosed space;
- carbon emissions from transporting material to a landfill and processing it;
- wasteful land use.
Co-generation plants to convert the methane into electricity must be balanced against:
- cost of the plant and its operation, and the extended non-usability of the land;
- escaped methane and carbon emissions produced while generating electricity.

2.2 Sewage system processing

Problems related to in-sink waste disposal units include:
- significant costs and land-use required to re-oxygenate water before it reaches waterways;
- valuable clean water wasted in the process;
- valuable nutrients poured down the drain;
- nutrients mixed with sludge including contaminants like heavy metals;
- remaining bio-solids often end up in the landfill.
In-sink disposal systems may have a place in high-rise apartments – if /when the material can be processed into bio-fuels and /or soil conditioner at a viable cost without contamination or net carbon emissions.

2.3 Centralised composting

Problems related to centralised composting operations include:
- difficulty of getting households to separate organic waste;
- reduced incentive when households have to pay to have material taken away and then pay again to buy the resulting compost;
- capital costs, and ongoing expenses of collecting, transporting and processing material;
- carbon emissions from collecting, transporting and processing machinery;
- spontaneous combustion (in windrows) requiring monitoring and means to extinguish;
- contamination – either intentional (people getting rid of toxic stuff) or unintentional (eg: grass clippings from lawns sprayed with weed killer containing Chlopyralid resulting in compost that may distort some plants and is therefore not saleable.)
- difficulty in finding markets to distribute the resulting compost.

2.4 Worm farms

Problems related to worm farms include:
- labour intensive – many people give up on them because they require ongoing maintenance, eg: schools experience problems over holiday periods;
- UK Open University research has claimed that red worms emit high levels of nitrous oxide – 296 times more powerful than CO2; http://www3.open.ac.uk/media/fullstory.aspx?id=11437 . This suggestion has been around for over ten years – in May 1998 The New Scientist said:
Common garden earthworms ooze laughing gas, or nitrous oxide. As a greenhouse gas, the exhalations could contribute to global warming, researchers told last week's meeting of the American Society of Microbiology in Atlanta.

2.5 Home composting

Benefits associated with home composting include:
- reduced methane emissions from landfills;
- reduced collection costs and carbon emissions from transporting and processing material.
Problems related to single bin home composting can include:
- methane gas is emitted unless material is regularly aerated through lifting and turning;
- new material is mixed with old material if /when it is lifted and turned;
- composting is not sustained when households give up if /when it becomes smelly (anaerobic) and /or because trying to do it properly requires too much hard work.
Problems related to rotating drum home composting, apart from its initial cost, can include:
- it is usually stated that only garden waste can be used, ie: no food waste;
- it is a batch production process – material must be stored while waiting for the next batch;
- it requires daily turning to aerate the material and accelerate production.

2.6 The Earthmaker option

Benefits associated with Earthmaker Aerobic Composter include:
- easy to use – three stages stacked vertically, so gravity does the hard work – which means households don’t give up;
- aerobic – new waste material is supported on shelves above the ground and heat, absorbed from the sun through the black domed top and naturally generated by the decomposition process, draws air up through the holes under the material. This adds oxygen to the process so that organic waste breaks down faster while much less methane is produced;
- aeration is increased when material loosens as it spills from shelf to shelf;
- continuous cycle process – new food and garden waste can be added when convenient while mature mulch or compost can be removed when needed;
- faster and easier – in 2006 the HDRA (now known as Garden Organic) Sustainable Waste Management Team at Ryton in the UK completed a 26 week trial of Earthmaker versus traditional compost bins and concluded that Earthmaker is easy to use, produces compost faster than traditional bins, makes over twice as much ready to use compost as traditional bins over the same period, and is easy to empty. (See Appendix 2)
- makes excellent compost – in 2002 tests conducted and supervised by an independent NZ Crown Research Institute*, with nutrient analysis performed by Hill Laboratories Ltd, showed that Earthmaker compost is safe, nutritious, has a very positive effect on plant growth and exceeds the requirements of the NZ Compost Standard.
- creates a carbon sink – the www.globalrepair.ca* website reports that the Environmental Protection Agency concludes aerobic composting does not contribute to CO2, CH4, or N2O emissions, the main contributors to greenhouse gas response and global warming, and: 
- any emissions from aerobic composting are considered part of the natural carbon cycle;
- proper aerobic composting eliminates methane production;
- aerobic compost creates a “sink”… sequestering (locking up) the carbon in the soil. 
In their paper The potential role of compost in reducing greenhouse gases Favoino and Hogg say “the absorption potential of agricultural soils could contribute significantly to constraining growth in greenhouse gas emissions, while also contributing to improvements in soil quality … Typically, life-cycle analyses … tended to obscure the potentially important effect of composting, in which biogenic carbon is held in soils for a period of time before the carbon is released.” (Contact us for a copy of the Favoino and Hogg abstract.)
* More on Testimonials and News pages at www.earthmaker.co.nz and www.earthmaker.com.au

3. Tools to change behaviour


3.1 Tools teach faster than education

Giving people effective tools will change behaviour faster than earnest education or the threat of punishment. Examples of tools changing behaviour across many personality types and socio-economic groups are desktop computers, the internet, cell phones and digital cameras.

3.2 Common tools for domestic waste management

The 240 litre ‘wheelie bin’ was an example of a tool that changed behaviour for the worse –residents filled them up resulting in a significant increase in household waste sent to landfills.
User-pays bags and curb-side recycling bins are tools that have encouraged better behaviour.
Most tools for easily managing domestic organic waste have not encouraged good behaviour:
- Kitchen waste pulverisers consume energy and water then send nutrients to re-oxygenation plants which in turn consume space and energy.
- Kerb-side collection of green waste often excludes food waste, requires energy for transport and processing and is vulnerable to contamination.
- Single bin composters often result in material left to rot in a smelly, anaerobic state creating leachate and methane gas. Many users give up because it is hard to remove compost while leaving unprocessed material behind and they dislike the smell, the mess and the effort.

3.3 Earthmaker – the tool to change behaviour

The Earthmaker Aerobic Composter is a tool that offers the easiest option because:
- food waste and garden waste is added when convenient;
- material is held in the upper chamber where warm air is drawn up through natural convection to assist the aerobic process, thus reducing greenhouse gas emissions;
- pushing material over the edge of the shelf and through to the next chamber achieves the loosening and turning effect of traditional three-bin composting, but without the hard work;
- material reaching ground level has become mulch and, if left, will become friable compost;
- mature material can be easily extracted when required.
The Earthmaker is a tool that can change behaviour for the better.

3.4 ‘Give us the tools and we will finish the job’ – Winston Churchill, 1941

Methods for getting the right tools to households range from distributing them in the same way as wheelie bins to offering vouchers for purchase through retail outlets (who may choose to participate as an act of social and environmental responsibility – with obvious PR and store-traffic benefits). An appropriate roll-out strategy tailored to each community will be required.

3.5 Feedback from the frontline

The Australian Capital Territory (ACT) State Government trialled a range of composters and worm farms at schools and found the Earthmaker was the most popular and effective option. By August 2008 Earthmakers were being used in 30 schools and promotion continues as part of their Sustainable Schools programme. The ACT government estimates that schools can reduce their waste by up to 45% by compositing their organics using the Earthmaker.
Earthmaker composters are by far the easiest for schools to use. – Evatt Primary
Earthmakers are the no dig, no smell, no fuss way for schools to recycle their organics. – Holy Spirit School

4. Incentives and costs


4.1 Motivating residents

Aerobic home composting can be encouraged through incentives for adopting effective technology and disincentives for using less desirable methods. Aerobic composters could be offered to households at no cost while the cost of less effective methods could be increased.

4.2 Capitation applied to waste management

The model in which a contractor is paid according to the amount of material collected and transported and a landfill operator is paid according to the amount of material taken sends the wrong signals – it is a case of ‘the more the better’ for a profitable operation.
If contracts were funded on a population basis (ie: capitation – remuneration based on the number of households managed, not tonnage to landfill) it would be in the contractor’s best commercial interest to manage waste at source, ie: inside the gate. If the contract allowed for the supply of ‘the right tool’ for home composting, behaviour would change for the better.

4.3 Equipping households

The fastest way to equip the community with ‘the right tool’ would be to supply Earthmakers free or subsidised to households who want them – either through contractors or retail outlets.

4.4 Lease-back option

Earthmaker Enterprises has developed a leasing model which allows local bodies to provide composters to their communities without requiring capital expenditure. Monthly lease payments are offset by the savings in reduced organic material having to be collected and processed. Earthmaker Enterprises will devise a lease option tailored to each council’s requirements.

4.5 Education

Education could enhance the success of aerobic home composting. Earthmaker Enterprises will work with Councils, schools and community groups to develop education materials.

4.6 Support

As part of the education process, Earthmaker Enterprises is willing to work in partnership by providing dedicated support for the first 12 months. The Earthmaker support person could be the point of contact for customer enquiries and would liaise with schools, community groups and Council officers to ensure the successful implementation of Earthmaker composting.  

4.7 Benefit analysis

Earthmaker Enterprises will collaborate with Councils willing to consider purchasing or leasing significant numbers of Earthmaker Aerobic Composters to produce an environmental and cost benefit analysis tailored to specific communities.

4.8 Carbon credit potential

The potential for earning carbon credits through aerobic composting is under discussion around the world. Work is needed to identify how this could be applied and managed to the most ecologically sound means of processing organic waste – ‘earthmaking’ at home.