Towards low energy-carbon footprint: Current versus potential P recovery paths in domestic wastewater treatment plants

With the unprecedented exhaustion of natural phosphorus (P) resource and the high eutrophication potential of the associated-P discharge, P recovery from the domestic wastewater is a promising way and has been putting on agenda of wastewater industry. To address the concern of P resource recovery in an environmentally sustainable way is indispensable especially in the carbon neutrality-oriented wastewater treatment plants (WWTPs). Therefore, this review aims to offer a critical view and a holistic analysis of different P removal/recovery process in current WWTPs and more P reclaim options with the focus on the energy consumption and greenhouse gas (GHG) emission. Unlike P mostly flowing out in the planned/semi-planned P removal/recovery process in current WWTPs, P could be maximumly sequestered via the A-2B- centered process, direct reuse of P-bearing permeate from anaerobic membrane bioreactor, nano-adsorption combined with anaerobic membrane and electrochemical P recovery process. The A-2B- centered process, in which the anaerobic fixed bed reactor was designated for COD capture for energy efficiency while P was enriched and recovered with further P crystallization treating, exhibited the lowest specific energy consumption and GHG emission on the basis of P mass recovered. P resource management in WWTPs tends to incorporate issues related to environmental protection, energy efficiency, GHG emission and socio-economic benefits. This review offers a holistic view with regard to the paradigm shift from simple P removal to P reuse/recovery and offers in-depth insights into the possible directions towards the P-recovery in the water-energy-resource-GHG nexus plant.

Automated summary

With the exhaustion of natural phosphorus resource and its associated high eutrophication potential, phosphorus recovery from domestic wastewater has gained attention in the wastewater industry. This review focuses on the energy consumption and greenhouse gas emission of different phosphorus removal and recovery processes in wastewater treatment plants. The A-2B- centered process shows the lowest energy consumption and greenhouse gas emission for phosphorus recovery. This review provides insights into the paradigm shift towards phosphorus reuse/recovery and offers a holistic view on phosphorus resource management in the water-energy-resource-GHG nexus plant.