Is further testing done on the land where we use our compost or further testing on the produce consumed?

The SMRC’s industry partner, Nutrarich, undertakes further processing of the compost. Compost from the WCF is blended with other soil conditioners and used in agriculture.

The final compost product is suitable for unrestricted use in farms, parks and gardens

What are we doing to close the gap to reach the state goal of zero waste to landfill?

With the support of the community, the RRRC can continue to deliver many positive environmental, social and economic outcomes.

Reflecting the State Government’s vision, the SMRC is working towards a sustainable, greenhouse friendly, zero waste future through:

  • Diversion of kerbside collected waste from landfill
  • Increased processing and recovery of kerbside collected recyclables
  • Diversion of green waste from landfill
  • Producing by-products such as compost, mulch and recycled materials
  • Improved resident awareness and engagement

In addition, at the June Regional Council meeting, Council selected Nutrarich for the beneficial reuse and removal of organic screenings from the waste composting facility. This material, known as compost 2, results from the filtration processes at the waste composting facility.

By improving processing, and working with the industry we are now able to ensure this material receives additional composting increasing the amount of organic household waste diverted from landfill by the RRRC.

Up to an additional 7,500 tonnes of household waste is expected to be diverted from landfill as a result of this decision, making this a significant step forward in achieving the State Government goal of zero waste by 2020.

What do we test each batch of compost for and why?

Compost from the RRRC undergoes testing for a large number of possible contaminants prior to leaving the facility. This is why it is important not to put Household Hazardous Waste (HHW) such as bleach, insecticides and fertiliser etc in your green-topped bin. Click here for which bin to use

Can people buy the compost from Nutrarich? Or will they ever be able to?

Because the home compost market is already well serviced in Perth, the SMRC works with the agriculture industry supplying compost for use in farming in the South West. Local governments also use the compost in their parks and gardens.

What is the main smell coming from SMRC?

At RRRC the potential sources of odour are the waste composting facility’s biofilters, which may emit a damp, earthy or woody smell from time to time. This is usually weak and the odour management systems reduce the risk of unreasonable odours leaving the site.

What kinds of chemicals do you use and what by-products are released into the atmosphere?

No chemicals are added to the rubbish used in the composting process at the RRRC.

Where do the wood chips come from?

The wood chips in the biofilters come from a number of sources, including the RRRC’s green waste processing facility.

Is the bio-filter organic or are chemicals involved?

Biofilters are organic. They are a mix of wood chips and micro-organisms which do the work of ‘eating’ the odour and changing it into an earthy, woody smell, much as you would experience in a forest.

How is the rubbish broken down? What kind of process is it?

The SMRC has adopted an aerobic in-vessel waste composting process to treat Municipal Solid Waste (MSW). Aerobic waste composting is a mature technology in the United States and Europe. The concept is natural and simple. Two waste streams, MSW and liquid waste, are composted to recover the organic component and produce a stable compost. Primary process aspects are as below:

  • Once bulky non-biodegradable items and hazardous material are separated from the waste stream, the remainder is batch-fed into the first compartment of the three compartment rotary digester (known as Eweson Digester). Liquid waste is also fed into this compartment when required. If no liquid waste is received, it is replaced by water.
  • An aerobic decomposition process takes place in the digester as it rotates, and temperatures are maintained at an average of 50ºC. The waste is batch transferred between compartments each day until after three days the resulting material is prepared for secondary composting stage.
  • The raw compost is then transferred to the aeration floor building for further maturation for 28-29 days. After which it passes through a fine screening system to produce the finished compost.

What can compost be used for?

  • Farmers use compost for enhancing crops.
  • Landscapers use compost as a soil amendment and for decorative purposes at properties, golf courses, and athletic fields.
  • Nurseries use compost for enhancing plant and forest seedling crops in reforestation projects and to prevent certain plant diseases.
  • Public agencies use compost for landscaping highway median strips, parks, recreational areas, and other public property and remediating contaminated or eroded sites.
  • Homeowners use mature compost to enrich gardens, improve the soil around trees and shrubs, use as soil additive for house plants and planter boxes and as protective mulch for trees and shrubs.

What are the benefits of Compost?


  • Compost returns organic matter to the soil which improves soil structure, water infiltration, and water holding capacity of the soil. This has many beneficial implications, including reducing the demand for irrigation water used in intensive agriculture and working towards sustainable yields.
  • Improved water quality by cost effectively converting liquid and solid wastes (that often pollute waterways) into recycled organic products that reduce the leaching of nutrients into natural water bodies.


  • Compost can contribute to sustainable land management by improving soil quality, assisting plant growth and vegetation establishment, increasing water holding capacity, storing carbon in the soil and reducing the need for chemical fertiliser and pesticide inputs.
  • Composting can assist to address the cause of nitrification and salinity.
  • Compost slowly releases macro and micro-nutrients for plant growth. This reduces the need for fertiliser, and makes existing fertiliser programs more effective.
  • Soil enriching composts improve the structure of sandy soils allowing them to retain moisture and nutrients longer; they also provide the nutrients necessary for healthy plant growth.

What are the benefits of turning rubbish into resources?

Global Warming

  • Around 90% of greenhouse gas emissions from landfills are a result of decomposing organic material. Composting garden materials and food scraps diverts this organic matter from landfill.
  • Composting reduces the quantity of waste going to landfill. This means that only waste that cannot be composted will be disposed of at landfill. This inert waste is not organic and does not release damaging leachates and methane, a potent greenhouse gas.

How much waste can the WCF process a year?

The WCF is capable of processing up to 109,000 tonnes of solid waste and some 600 tonnes of liquid waste. In an average year the WCF processes around 80,000 tonnes of household rubbish.

What happens to the residuals?

The RRRC’s waste composting facility processes the organic rubbish residents place in their green top bin turning this material into compost. Kitchen scraps, lawn clippings, garden prunings and other organic household waste placed in the green top bin will be composted; light globes, plastic bags and inorganic material placed in the green top bin cannot be composted and must be disposed of at landfill.

What happens to the SMRC compost after the final screens?

Nutrarich takes all the final product compost from the waste composting facility for use in agriculture in the South West. Based in Brookton, Nutrarich is an experienced soil additive and conditioner manufacturer with a long history in the industry.