Waste-to-energy facility in WA

Biogass Renewables recently commissioned a large-scale commercial and industrial organics waste-to-energy reference facility for Richgro Garden Products in Jandakot, Western Australia. The site has been designed for 35,000 tons per annum of food waste and can handle up to 50,000 tons per annum, producing over 2 MW of electricity and 2.2 MW in heat.

The plant comprises three key stages — reception, digestion and energy. The reception building receives solid and liquid waste streams from commercial and industrial sectors such as supermarket food waste, market fruit and vegetable waste, abattoir waste, agricultural waste streams and food processing facilities. A preprocessing system de-packages and removes all contamination to give a clean pumpable feedstock for processing onto the digestion process.

Anaerobic digestion operates at a mesophilic temperature — circa 36°C — and is a continuous flow digestion process, diet-feeding a small volume into each of the two primary digesters. The process maintains a stable neutral PH, with the digestion phase breaking down fatty acids into methanogens to give methane (CH₄). Biogas captured in the digester gas holders is between 60–65% CH₄ with the rest made up of carbon dioxide (CO₂) and a small amount of hydrogen sulfide (H₂S).

In the third stage, biogas is drafted off from the digester, chilled down to its dewpoint to remove moisture before boosting to a containerised co-generation set producing heat and power via a reciprocating high-efficiency engine. The first unit installed will provide 1.2 MW of power and 1.26 MW of heat, this will service Richgro’s entire energy draw on a behind-the-meter basis and export up to 1 MW back into the grid.