화학공학소재연구정보센터
Chemical Engineering Research & Design, Vol.90, No.1A, 78-85, 2012
Phosphorus recovery from centralised municipal water recycling plants
Depletion of world phosphorus reserves is driving research into options to recover and recycle this essential, non-renewable resource. Phosphate (PO43-) recovery at centralised wastewater treatment plants can be achieved through biosolids reuse or sidestream precipitation though the PO43- levels are low compared with decentralised systems based on source separation. However, the recent growth in membrane based water recycling projects, where reverse osmosis is used to produce high quality water has resulted in the production of liquid waste streams with elevated concentrations of PO43-. Four recycling scenarios using different membrane processes and anaerobic treatment were compared and the potential PO43- recovery via struvite (magnesium ammonium phosphate) from membrane concentrate examined. By incorporating an anaerobic reactor in the process we have been able to investigate the possibility of cogeneration of electricity from methane. Modelling of struvite recovery from membrane concentrate with co-generation indicates a net power requirement of 260 kWh/kg P recovered compared with 510 kWh/kg P for a system without cogeneration at a water consumption level of 250 L/p/d. When water consumption is limited to 80 L/p/d, this scenario compares favourably with literature values for recovery from source separated urine which range from 18 to 43 kWh/kg P. Crown Copyright (C) 2011 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved.