Struvite recovery options in conventional wastewater treatment plants (WWTPs)

In the face of increased demand for phosphorus recovery from waste and in particular from wastewater,the study deals with the opportunities offered by the sludge obtained in applying chemicals phosphorus removal (cpr) and biological phosphorus removal (bpr). two case studies of bulgarian municipal wwtps are used as examples of cpr and bpr and sources of sludge generated in the corresponding plants. the high yield of struvite in treatment of sludge dewatering liquor from an activated sludge system with anoxic and oxic zones demonstrates the effectiveness of the application of sea water brine as a low cost magnesium source. the effects of co2 stripping and bio-electrochemical alkalinity generation on ph elevation through the process of struvite formation are shown for real sludge dewatering liquor in both laboratory and bench scale units. in addition,the potential of phosphorus mobilization from fepo4 by microbial fuel electrolysis cell and the potential of such a process to be applied as a pre-step for struvite production from sludge developed in a cpr wwtp are revealed.