Reuse of drinking water treatment residuals in a continuous stirred tank reactor for phosphate removal from urban wastewater

This work proposed a new approach of reusing drinking water treatment residuals (WTR) in a continuous stirred tank reactor (CSTR) to remove phosphate (P) from urban wastewater. The results revealed that the P removal efficiency of the WTR was more than 94% for urban wastewater, in the condition of initial P concentration (P-0) of 10 mgL(-1), hydraulic retention time (HRT) of 2h and WTR dosage (M-0) of 10 gL(-1). The P mass transfer from the bulk to the solid-liquid interface in the CSTR system increased at lower P-0, higher M-0 and longer HRT. The P adsorption capacity of WTR from urban wastewater was comparable to that of the 201 x 4 resin and unaffected by ions competition. Moreover, WTR had a limited effect on the metals' (Fe, Al, Zn, Cu, Mn and Ni) concentrations of the urban wastewater. Based on the principle of waste recycling, the reuse of WTR in CSTR is a promising alternative technology for P removal from urban wastewater.