A Novel Combined System for Onsite Domestic Wastewater Treatment in Rural Areas

Abstract

A combined system, which consisted of an innovative septic tank (IST) and compound media filter bed (CMFB), was used for onsite domestic wastewater treatment in a rural area. Performance of this system was evaluated by both bench-scale and pilot-scale experiments. The system showed relatively good removal efficiency of chemical oxygen demand (COD) and suspended solids, but removal efficiencies of total phosphorus (TP) and total nitrogen (TN) were not so impressive. Correlated regression models provided good estimates of the nutrient removal performance in this system. Hydraulic retention time (HRT) had a positive effect on nutrient removal. Ambient temperature had no obvious relationship with the suspended solids (SS) and TP removal in the system. By contrast, ambient temperature had a significant effect on COD removal (p < 0.05). Furthermore, the nutrients were hard to remove in cold seasons. During the operation period, this system showed high treatment capacity for rural domestic wastewater treatment with good landscape integration. Results demonstrated that this IST + CMFB system could be a practical technology for onsite domestic wastewater treatment in rural areas.