Enhanced energy recovery through anaerobic co-digestion in the Australian industry

Anaerobic digestion is widely used by Australian municipal and agri-industries to treat organic waste and produce energy rich biogas. With so much large infrastructure now in operation, there is growing interest in strategies to leverage this investment and maximise biogas production. Anaerobic co-digestion (AcoD) is a promising strategy which involves simultaneously digesting two or more different types of wastes. Some municipal and agri-industrial wastes (e.g. livestock manure, sewage sludge) have relatively low-energy potential therefore co-treatment with other high-energy wastes (e.g. Fat, Oil and Grease) or wastes from a local industry (e.g. glycerol) can substantially increase biogas production. With additional benefits from diverting more organic waste away from landfill and potentially increasing the nutrient-value of the digested material. However, not all wastes are compatible and it is important that AcoD is properly managed to realise the benefit and avoid the risk of process failure.

Current ACWEB research is enhancing the fundamental understanding of co-digestion risks and drivers for the benefit of municipal and agri-industries. Experiments are being conducted at laboratory-scale to characterise the degradation properties of different wastes under different process conditions and leading to a comprehensive modal and co-digestion manual. Results are being validated at full-scale with the support of industry partners.

Funding

Meat and Livestock Australia
Melbourne Water
AMPC
Port CRC
Urban Utilities

Project Outcomes

Key project deliverables include :

Fundamental knowledge on how waste composition impacts degradation properties to develop co-substrate compatibility metrics.
Successful co-digestion case studies at laboratory and full-scale.
Co-digestion manual detailing strategies for selecting suitable amounts and compositions of waste mixtures.
Cost-benefit analysis and risk analysis for potential co-substrates suitable for co-digestion with municipal and agri-industrial waste streams

Publications

Arnell M, Astals S, Amand L, Batstone DJ, Jensen PD, Jeppsson U. (2016). Modelling anaerobic co-digestion in Benchmark Simulation Model No. 2: parameter estimation, substrate characterisation and plant-wide integration. Water Research: 98 (2016), p 138-146.
Astals S, Musenze RS, Bai X, Tannock S, Tait S, Pratt S, Jensen PD (2015). Anaerobic co-digestion of pig manure and algae: Impact of intracellular algal products recovery on co-digestion performance. Bioresource Technology: 181(2015) p97-104.
Jensen PD, Astals S, Lu Y, Devadas M and Batstone DJ. (2014). Anaerobic codigestion of sewage sludge and glycerol, focusing on process kinetics, microbial dynamics and sludge dewaterability. Water Research: 67(2014) 355-366. IF: 5.323
Jensen PD, Sullivan T, Carney C and Batstone DJ. (2014). Analysis of the potential to recover energy and nutrient resources from cattle slaughterhouses in Australia by employing anaerobic digestion. Applied Energy: 136(2014) 23-31. IF: 5.261
Astals S, Mata-Alvaez J, Batstone DJ and Jensen PD. (2014). Identification of synergistic impacts during anaerobic co-digestion of organic wastes. Bioresource Technology. 169 (2014) 421-427. IF: 5.039