Resources recovery from Australian biosolids: technology options

Australia has over 700 community sewage treatment plants which combined produces over 400,000 tonnes of biosolids per year on dry basis. Around 55% of the biosolids are used as inexpensive fertilizer and the remainder is composted, stockpiled or landfilled. Although preferred from a sustainability perspective, future agriculture applications of biosolids may be limited because of logistical and transportation issues, ever more stringent regulatory requirements and public perception of using for using material directly for food production. Biosolids contain a range of high fraction-low value resources (N and P) and low fraction-high value resources (Cu, Al, K). Much of the current research is focussed on energy and agronomic benefits of the biosolids, while resource recovery is largely overlooked. Recent price increases of inorganic fertilizers and other precious metal have motivated a study of technology options for recycling resources from Biosolids. These technologies will produce high-value products and spent biosolids can be used as a soil conditioner