The composting process is one in which micro-organisms (and small animals) break down plant material and similar organic matter to produce a humus-like final material, in conjunction with carbon dioxide, water and heat.
Bacteria and fungi are the main micro-organisms, while small animals such as worms and nematodes help with physical breakdown processes. After a final maturation or ‘curing’ phase, the compost is ready to be used for soil improvement and as a growing medium.
Wastes that can be used include animal manures, green wastes from parks and gardens, certain industrial wastes as well as food wastes. Quality composted wastes are suitable for use as soil improvers and a growing medium.
Compost guideline – industry consultation
In 2007 the EPA released the draft Guideline for Composting Works in South Australia which went through public consultation. Submissions were received from industry, including licensees, consultants and government. The EPA reviewed the comments, which generally supported the publication of a compost guideline. A response to the comments can be viewed in the summary of submissions to this earlier guideline.
An industry sector audit will be carried out in 2013 to determine the level of compliance with the EPA's regulatory expectations as detailed in the compost guideline.
The EPA is the primary regulator of large-scale licensed composting operations. We work with operators to ensure that the composting process has a minimum impact on the environment and produces quality compost.
The compost industry has steadily grown in productivity over the past decade and is looking for ways to secure ongoing growth within a competitive waste industry. There is a strong push to diversify the range of currently acceptable waste streams as feedstocks. This has increased the risks associated with the conduct of composting works. Of particular concern are the increased risks to groundwater beyond nutrient loading as a result of non-traditional feedstocks.
The EPA supports the use of composting as one of the ways of recovering valuable resources from our waste streams, which would otherwise be sent to landfill.
Biodegradable wastes in landfill produce carbon dioxide, methane and leachate. Methane is a potent greenhouse gas with 23 times the global warming potential of carbon dioxide.
Municipal waste composting has grown over the last few years as many local councils have introduced separate green waste and food waste collections.
The EPA understands the need for there to be sufficient composting facilities available to meet growing demand, so that the effective operation of existing plants is not undermined. It is also essential that these facilities are located, operated and regulated so that there is minimum impact on the environment and human health.
Environmental authorisation requirements
An environmental authorisation is required to establish a large-scale composting facility producing (or are capable of producing) over 200 tonnes per annum of mushroom or other compost. The authorisation is required, as composting works are defined as an activity of environmental significance in Schedule 1, Part A, 6(3) of the Environment Protection Act 1993 (the Act).
Prior to the issue of an environmental authorisation you will need to obtain development approval (defined as a Schedule 22 activity under the Development Act 1993). The Development Assessment Commission (DAC) is the planning authority dealing with the development approval. A comprehensive guide to development assessment process can be found on the DAC website.