MFC COD removal efficiency (%) Initial COD (mg/L) 1010 1019 1023 1045 average unmodified 57.9 60.5 57.8 57.7 58.5 PPy-1 62.3 64.5 71.8 64.0 65.6 PPy-2 59.9 59.7 68.9 57.8 62.6 PPy-3 61.9 61.5 69.6 64.0 64.3

Table 1: COD removal efficiencies of four MFCs.