Two stage hybrid constructed wetland microbial fuel cells for swine wastewater treatment and bioenergy generation.
A newly emerged alum sludge based hybrid constructed wetland microbial fuel cells (CW MFCs) i.e. vertical upflow CW coupled MFC as 1st stage and horizontal subsurface flow CW coupled MFC as 2nd stage (VFCW MFC HSSFCW MFC) was firstly developed for swine wastewater treatment and electricity generation. Swine wastewater and multi set air cathodes were applied to investigate the pollutants removal behavior and the power production. Six month trial suggested that the overall removal efficiency of SS, COD, NH4+ N, NO3 N, TN, TP and PO43 P was 76 12.4, 72 7.4, 59 28.3, 69 25.6, 47 19.7, 85 9.5 and 88 8.7% respectively. The two stages hybrid system (VFCW MFC HSSFCW MFC) continuously generated electrical power with average voltages of 0.44 0.09 and 0.34 0.09 V, and power densities of 33.3 13.81 and 9.0 2.5 mW/m3 in 1st and 2nd stage, respectively. The average net energy recovery (NER) of 1st stage and 2nd stage is in turn 0.91 0.16 and 2.76 0.70 Wh/kg*COD. It indicates that the hybrid CW MFCs has higher removal efficiency than single stage CW MFC, while 1st stage plays the major role both in pollutants removal and power generation.
Chemosphere