Domestic wastewater treatment for single household via novel subsurface wastewater infiltration systems (SWISs) with NiiMi process: Performance and microbial community

Abstract

Subsurface wastewater infiltration systems (SWISs) were widely used in decentralized domestic wastewater treatment. However, their clogging risk and unstable performance remain pressuring issues. In this study, novel SWISs with NiiMi process have been developed in the treatment of domestic wastewater. Moreover, the impacts of substrates and operating modes on removal performance of SWISs were systemically evaluated. The results indicated that optimal removal performance was achieved in Sandy soil system with intermittent time of 6h and RWD of 1.0. The removal efficiencies of chemical oxygen demand (COD), total phosphorus (TP), and NH4+–N of best-performing Sandy soil system reached 94.81%, 97.25% and 75.02%, respectively. The average removal rete of COD, TP, and NH4+–N of Sandy soil system reached 35.80, 0.74, and 2.79 gm−2d−1, respectively. The effluent of Sandy soil system has satisfied the limits of The Reuse of Urban Recycling Water (GB/T 18921–2002). High-throughput sequencing indicated that the percentage of denitrifiers in Krasnozem system, Brown soil system, and Sandy soil system reached 58.95%, 64.79%, and 25.31%, respectively. Pseudomonas, Anaerolineaceae-uncultured and Bacillus were predominant functional genera in carbon and nitrogen cycling of SWISs. Overall, the Sandy soil system with NiiMi process is feasible for single household in the treatment and reclamation of domestic wastewater.