Frequently Asked Questions – Collie Project

Where will the plant be located?

The plant will be located within the current Shire of Collie landfill site.

What will the plant be processing?

The priority will be to process the municipal wastes generated by the residents in the Shire of Collie that are suitable for processing by the plant. The exact types of municipal wastes to be processed by Renergi will be determined jointly by the Shire of Collie and Renergi. Renergi’s plant will be designed to process a range of biomass waste types. 

In addition, Renergi’s plant will process around 8,000 tonnes/year of forestry waste or other biomass wastes.


What sorting of waste will be done before it enters the plant?

The Shire of Collie and Renergi will develop a waste management system. This will be done in consultation with the Collie community. Residents may be required to place their wastes into appropriate bins. However, the Shire of Collie will not be required to carry out any additional sorting before the wastes are delivered to Renergi’s plant.

What will the plant be producing?

Initially Renergi’s plant will be designed to produce two key products: biochar and bio-oil. Subject to strict quality testing to meet relevant standards, biochar will be mainly sold for use in soil to improve soil productivity and sequestrate CO2 that has been emitted into the atmosphere (negative emission). Some biochar will be sold as part of animal feedstuff to improve animal health/productivity and to reduce emissions. Bio-oil will be sold as an industrial fuel.

Renergi will also consider producing other commercial products.

What is the difference between Renergi’s technology and incineration?

Renergi will design, construct and operate the pyrolysis plant based on its own patented award-winning technologies. Renergi’s technologies have been developed in WA.

Pyrolysis is the thermal decomposition of feedstock, e.g. forestry wastes, agricultural wastes and municipal solid wastes, in the absence of sufficient air. The pyrolysis process will produce three products: non-condensable gases, liquid bio-oil and solid biochar. While bio-oil and biochar will be sold as commercial products, the non-condensable gases will be burned within the plant to supply the heat required by the pyrolysis process itself. Renergi’s plant will also use the waste heat to dry the feedstock.

It is therefore clear that Renergi’s pyrolysis process is drastically different from the incineration of wastes. In a normal incineration process, excess air is supplied to ensure the “complete” combustion of combustible materials. The main products are CO2 and H2O. In modern incineration plants, the heat released is used to generate electricity.

Renergi’s pyrolysis process will be operated over a relatively low temperature range (e.g. around 350-550°C). However, the incineration of wastes normally takes place at much higher (e.g. >1,000°C) temperatures.

Renergi’s pyrolysis process also differs from high-temperature (e.g. >800°C) pyrolysis processes.

As an inherent advantage of low temperature pyrolysis and Renergi’s patented technology, Renergi’s pyrolysis operating conditions are designed to minimise the formation of air pollutants. In particular, the combustion of non-condensable gas, which is a relatively clean gaseous fuel and represents a small mass fraction of the feedstock, will take place at sufficiently high temperature with excess air supply, turbulence and long residence time to minimise the formation of air pollutants, including the minimisation of dioxins and dioxin-like compounds.

Renergi’s operation will minimise manual handling of municipal solid wastes to minimise odour issues, which are common in many other waste management practices.

Renergi will carry out extensive monitoring of possible pollutants from its process to ensure that Renergi’s operation will meet all stringent regulatory requirements, for example, EPA requirements.

In fact, Renergi aims to set new standards for waste management.

How will Renergi manage heavy metal contamination?

Renergi will work with the Shire of Collie to improve the management of used batteries with the Shire of Collie to reduce the content of heavy metals in the municipal solid wastes entering Renergi’s plant.

The heavy metal contents in the biochar will be carefully quantified. Only biochar products meeting relevant standards will be used in soils or used as animal feedstuff.

Renergi’s plant will be designed to pyrolyse municipal solid wastes and forestry wastes separately. As a precaution, no biochar from the pyrolysis of municipal solid wastes, regardless of its quality, will be sold as animal feedstuff.

Will the plant contribute to smoke issues around Collie?

No. Renergi’s plant will be a closed system and will not release smoke into the atmosphere.