Research On Energy Flow Regulation Of MFC-MBR Coupled System

The MFC-MBR coupled system directly converts chemical energy from organic matter in the wastewater to generate electrical energy used to reduce the membrane fouling.Duing to energy competitions beteween the MFC and the MBR,the MFC-MBR system might have a poor performance.Based on the background above,we tried to strengthen the degradation and the electricity production by means of changing operational factors of MFCs.Then according to the above conclusion,the goal of the best filtering performance in coupled systems would be achieved by using the regulation of energy distribution under different organic loading.In addition,in order to study the mechanism of electric field on membrane fouling,the filtration performance of the separations in the activated sludge membrane were studied.The results showed are as follow:(1)It is successful to selectively strengthen the electric and organic degradation performance in microbial fuel cell.The process factors should be adapted to dynamically allocat the energy between the power generation and metabolic pathways under different load levels.(2)The dynamic regulation of energy distribution between the MFC and the MBR by using changing loads and sludge concentration could make the MFC-MBR coupled system achieve the longest running time.Studies on the energy regulation in coupled systems showed that we should stop the MFC reactor in the low-loading(Nv<0.14 kg-COD/(m3 d));as the influent energy at Nv=(0.14-0.41)kg-COD/(m3·d),we should maintain the activated sludge concentration at 5000mg/L and reduce the pH in MFCs to weak acid condition;as the influent energy at Nv=(0.41-0.96)kg-COD/(m3·d),we should maintain the activated sludge concentration at 8000mg/L and adjust the pH in MFCs to neutral condition and the resistance to low external resistance(R,<100?);as Nv>0.96 kg-COD/(m3·d),MFCs should be adjusted weak alkaline condition.(3)The main mechanism of the coupled system to mitigate the membrane fouling is to interfere with the deposition of SMP and LB-EPS on the membrane surface.The irreversible fouling could be reduced and the recovery of membrane flux could be improved under the condition that SMP and LB-EPS as the main irreversible fouling could be reduced under electric field.