Phosphate and Ammonium Removal from Water through Electrochemical and Chemical Precipitation of Struvite

Batch electrocoagulation (BEC), continuous electrocoagulation (CEC), and chemical precipitation (CP) were compared in struvite (MgNH4PO4 center dot 6H(2)O) precipitation from synthetic and authentic water. In synthetic water treatment (SWT), struvite yield was in BEC 1.72, CEC 0.61, and CP 1.54 kg/m(3). Corresponding values in authentic water treatment (AWT) were 2.55, 3.04, and 2.47 kg/m(3). In SWT, 1 kg struvite costs in BEC, CEC, and CP were 0.55, 0.55, and 0.11 euro, respectively, for AWT 0.35, 0.22 and 0.07 euro. Phosphate removal in SWT was 93.6, 74.5, and 71.6% in BEC, CEC, and CP, respectively, the corresponding rates in AWT were 89.7, 77.8, and 74.4%. Ammonium removal for SWT in BEC, CEC, and CP were 79.4, 51.5, and 62.5%, respectively, rates in AWT 56.1, 64.1, and 60.9%. Efficiency in CEC and BEC are equal in nutrient recovery in SWT, although energy efficiency was better in CEC. CP is cheaper than BEC and CEC.

Automated summary

Batch electrocoagulation (BEC), continuous electrocoagulation (CEC), and chemical precipitation (CP) were compared in struvite precipitation, showing similar nutrient recovery efficiency between CEC and BEC in authentic water treatment, with better energy efficiency in CEC; CP was found to be cheaper.