Effect of Hydraulic Retention Time on MFC-A2/O Process for Domestic Wastewater Treatment

Abstract

Abstract. A 10L scale MFC coupled A2/O system was built, with the anaerobic tank as anode chamber to remove carbon and the anoxic tank as cathode chamber to denitrify. This coupled system could achieve max output current after 30 days. During the study phase, the hydraulic retention time (HRT) was optimized to improve wastewater treatment efficiency and power generation. The results showed that the coupled system could obtain best pollutants removal effect when HRT=16h. Compared with control reactor, concentrations of COD and TN in the effluent of the coupled system could be reduced by 14.6% and 10.1%. And the power density (external resistance = 100Ω) of the coupled system was 612mW/m3 in the meantime. Correspondingly, the optimum HRT when the coupled system achieved highest power generation was 12h, and the max power density was 808mW/m3.

Impacts of hydraulic retention time on a continuous flow mode dual-chamber microbial fuel cell for recovering nutrients from municipal wastewater

“…Apart from this, some researchers thought high HRT may reduce the concentrations of substrate and the cell metabolism at the anode chamber (Liu et al, 2008), which inhibited the MFC reactor's production of energy. A reduced HRT results in more degradation of the substrate used for generating electricity at a unit time in the MFC system, thereby enabling biomass to convert energy (Luo et al, 2017). However, this scenario may require a higher concentration of EBA or stronger biofilm, which could oxidize more organics in a shorter time.…”

“…Luo et al (2017) found that longer HRT could even cause full oxidization of organics in domestic wastewater.In the study byGe et al (2013), they found that the removal efficiencies of COD were approximately 40-60% and 70-80% at the HRT of 10 h and 24 h, respectively, whilst continuously operating an osmotic MFC for domestic wastewater treatment. Similarly, Haavisto et al (2017) employed a two-chamber up-flow MFC to produce electricity from xylose, in which decreasing the HRT from 3.5 d to 0.17 d resulted in reduced removal of COD from 95% to 78%.…”