Wastewater, sludge and subsequent biosolids are large inherent energy sinks, and in most cases contain more energy than required to operate a treatment plant. The paper explores how this energy can be exploited to minimise plant demands. It finds that no one single measure can help achieve energy neutrality, rather a combination of processes.
The use of anaerobic digestion was found to reduce energy demands by over a third, and by 60% when combined with enhanced primary treatment. Energy neutrality was potentially achievable by combining these processes with further energy recovery downstream via burning as a cake. However, this study highlighted the poor energy extraction capability of anaerobic digestion when considered in a plant-wide envelope.
Read the full article in the Water Journal, Australian Water Association.