Performance of a combined low-consumption biotreatment system with cost-effective ecological treatment technology for rural domestic sewage treatment

Abstract

Treating rural domestic sewage has always been a hard task for rural vitalization in China. To overcome this problem, high-efficiency, easy-maintenance and low-consumption treatment technologies are urgently needed. To meet the requirements of rural sewage treatment, a new combined bio-ecological system was proposed in this study, including the anoxic filter (ANF), novel integrated guide-plate rotating biological contactors (NIGPRBC) and constructed wetland (CW). Key parameters of “ANF-NIGPRBC” system including hydraulic residence time (HRT), reflux ratio (RR) and rotational speed (RS) were identified founded on the organic matter and nitrogen removal performance for further application. In addition, the combined bio-ecological system was lasted for the 90 days at optimal operating parameters to confirm its performance on pollutant removal. The optimal operating parameters were determined to be 5 h HRTNIGPRBC, 100 % RR and 3 r/min RS. Under the optimal operating parameters, average 95.14 ± 1.31 % COD, 79.07 ± 4.32 % TN, 93.42 ± 2.16 % NH4+-N and 83.39 ± 3.46 % TP were removed during the 90-day operation. The operating results of the combined bio-ecological system indicate that the effluent meet local rural domestic wastewater pollution discharge standard. The microbial community results also helped to better explain the process performance of the whole system by high-throughput sequencing analysis. Proteobacteria and Bacteroidetes were the dominant phylum existing widely in this system. Denitrification-related genera were abundant both in ANF and CW. Overall, the new combined bio-ecological system is one of the priority choices for treating rural wastewater owing to its economic benefits, integrated design concept and convenient operation.