Research on rural sewage treatment using biological-ecological coupling process

Abstract

Developing low-investment, low-energy consumption and low-maintenance sewage treatment process is important for sewage treatment in rural areas. An upflow anaerobic filter (UAF) without energy consumption and a subsurface flow wetland (SFW) are utilized as a biological-ecological coupling process to treat rural domestic sewage. The effect of the coupling process on treatment performance of domestic sewage under different hydraulic retention time (HRT) is investigated. The removal of nitrogen and phosphorus in the SFW is improved by increasing plant density. The results show that the coupling process of UAF and SFW has no power consumption and is maintenance-free, suitable for rural sewage treatment; the removal of nitrogen and phosphorus mainly happens in the SFW phase; increasing the density of reed plants in the SFW can obviously enhance the capacity to remove nitrogen and phosphorus, and ensure that the efficient performance of the coupling process of UAF and SFW is stabilized in a high level. When the HRTs of UAF and SFW are 18 h and 3 d, respectively, the concentrations of COD, ammonia nitrogen, total nitrogen and total phosphorus in the final effluent treated by UAF and SFW process are 44.07, 4.25, 13.36 and 0.44 mg/L, respectively, meeting the requirement of first grade class A in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002).

Keywords

• water pollution control engineering
• rural domestic sewage
• anaerobic biological filter
• artificial wetland
• removal of nitrogen and phosphorus