Technologies for the wastewater circular economy – a review

Throughout the years, experiments with membrane, electrochemical, biological and thermal technologies have been explored to recover resources from a range of wastewaters such as municipal, industrial, urine and sewage sludge. However, multiple resource recoveries at the commercial and pilot scale are still lacking, instead, focusing on specialising on the recovery of a narrow set of products. Herein, a divergence of resource recovery across municipal and industrial wastewater streams – nutrients and energy for municipal; heavy metals and water recovery for industrial streams; with material recovery seen across both – was observed through literature review. This review aims to provide a perspective for academic and professionals alike on the current technologies available and their emerging trends – and aims to tie in these technologies to wastewater circular economics. Consequently, high sludge and wastewater transportation costs may pressure wastewater treatment plants (WWTPs) to adopt value-adding, resource recovery technologies onsite – transforming centralised and decentralised WWTPs into wastewater resources recovery facilities.