ADDRESSING TECHNICAL BARRIERS AT MERCHANT FOOD WASTE ANAEROBIC DIGESTION FACILITIES

The challenge

Merchant Food Waste Anaerobic Digestion Facilities (MFWFs) use anaerobic digestion to transform unavoidable food waste into renewable energy and green fertiliser. Food waste received by MFWFs is typically irregular/co-mingled/expired, making it difficult to re-purpose for animal feeds due to safety concerns, and impractical and/or uneconomical to extract higher value products. MFWFs are distinct from municipal wastewater facilities that co-digest food waste to utilise spare capacity/become energy-neutral in that they are purpose-built to turn food waste into beneficial products.

Unfortunately, many nitrogen-rich-fat-rich food wastes available to MFWFs cause severe inhibition of digestion, so digestion must operate at a much-reduced capacity. This decreases food waste diverted away from landfill by MFWFs by as much as 50%. Limited international research is available on this issue, and current solutions are impractical/uneconomical at full-scale. This is a key knowledge gap, because MFWFs will likely increase in number and frequency as Australia increases initiatives to divert food waste away from landfill. The project provides defendable guidance on waste types/amounts to process to maintain a high throughout.

Our plan

Together Martin Energy Group and Richgro Garden Products, in collaboration with University of Southern Queensland and Fight Food Waste CRC, addresses this limitation by testing and identifying acute and chronic digestion loading limits for high-fat and high-nitrogen food wastes (e.g., grease/meat). Testing uses state-of-the-art lab-scale experimental methods combined with process modelling and validation with full-scale data, to identify microbial capacity of the digestion process and to translate into general recommendations regarding waste mixture selection for merchant facilities. Expected outcomes include an increase in facility capacities and de-risking investment in prospective merchant facilities across Australia.

The following are key outcomes aimed to be achieved by the project:

• Reduced inhibition and increased capacity at Richgro Garden Product’s food waste anaerobic digestion facility based in Jandakot, Western Australia.
• De-risk investment into current and prospective food waste anaerobic digestion facilities for Martin Energy Group
• De-risk the roll out of new merchant food waste anaerobic digestion facilities across Australia giving Australian households, councils and industry more access to turn their unavoidable food waste into valuable products for the project partners and the wider industry.

The findings