THE EFFECT OF THE HYDRAULIC RETENTION TIME AND TEMPERATURE ON THE PERFORMANCE OF UP-FLOW ANAEROBIC FILTER REACTOR TREATING LOW STRENGTH RURAL DOMESTIC SEWAGE

Improper management of domestic sewage discharged by big cities and rural communities contains organic matter and nutrients substrates that may negatively interfere and affects lakes and streams by accelerating eutrophication process which in turns affect water quality of freshwater bodies. Application of up-flow anaerobic filter (UAF) reactor for the treatment of rural domestic sewage nowadays is extensively documented as efficient and cost-effective process reactor and importantly for organic matter and nutrients removal. This paper focuses on the effect of the hydraulic retention time and temperature on the performance of up-flow anaerobic filter reactor treating low strength rural domestic sewage. The influent was collected from a sewage manhole at the Taihu Lake Environmental Engineering Research Center of Southeast University, Wuxi, China. Two rounds of experimental operations were conducted in a laboratory scale. The UAF reactor systems composed of two columns made of polyvinyl chloride (PVC), with a total capacity of 200 L and both of them were typically operated as an anaerobic column. The UAF reactors were connected in a series with an internal diameter of 0.2 m and a height of 2 m. The columns were filled with non-woven fabric filter material of length 2.5 m, width of 50 mm, surface area of 150 m2/m3, porosity of 97% and an effective volume of 90 L for each column. In the course of the experimental operations, the effect of hydraulic retention time (1, 2, 3 and 4 days) and temperature (31.6, 32.95, 33.7, 16.4, 14.8 and 10.2℃) on organic and nutrients removal were experimented and analyzed. The pH value was maintain between 7.2 – 7.5. Accordingly, the optimum hydraulic retention time (HRT) and temperature observed in UAF was three days and 33.7℃with the maximum average chemical oxygen demand (COD) and total nitrogen (TN) removal of 91% and 65% respectively. The results of the experiments revealed high performance when the reactor’s HRT and temperature increases. The study concludes that, the UAF treatment of various biomass substrates from the low strength rural domestic sewage gives a number of advantages for management of wastewaters and prevention of water pollution.