Study On Treatment Of Domestic Wastewater With Up-flow Anaerobic Sludge Blanket Reactor

At present, aerobic treatment is widely used in urban domestic sewage treatment. Eighty percent of wastewater treatment plants in our country adopt activated sludge process. But the project investment and the expenditure of aerobic treatment is very high, which is not suitable for the situation of funds shortage, lack of energy and the pollution serious daily in our country. This paper studied up-flow anaerobic sludge blanket for the use of urban domestic sewage treatment which has the characters of simply management, low energy consumption, low operating cost, the scale of the treatment system can big or small and the system can be layed separated, residual sludge is small, stability and easily be dewatered. This technology is worth popularizing in our sewage treatment field.The study includes the start-up of UASB reactor and the performance for domestic sewage treatment in normal temperature, the effects of the operation parameters, the treatment effect of COD_Cr under optimal operation, the treatment effect of the reactor dealing with BOD₅, lower and higher concentration domestic sewage and SS, nitrogen, phosphorous. The result indicates that the UASB start quickly, work stably, have good removal effect of organic matter, bear high impact loads and have small sludge yield. In this experimentation the start-up of the reactor can be completed in about 33 days on condition that inoculation sludge was taken from dehydrated anaerobic sludge of the Tuandao wastewater treatment plant. It is 20～30 days shortter than kindred experimentations. Under the normal temperature(20.0～21.0℃), when the hydraulic retention time(HRT) is 7.69h, the removal of COD_Cr is 69.5～78.0%, COD_Cr of the effluent is less than 120 mg/L, which can meet the second class of Integrated wastewater discharge standard (GB8978-1996).SS of the effluent is about 50mg/L, the NH₃-N of the effluent is higher than that of the influent, and the total nitrogen is a small quantity of decreased. The system have a definite removal of phosphorous about 1.07～34.8%, a average of 16.8%, but the removal is not very good. The effluent can not meet the discharge standard, therefore, the following technology should be adopted according to the effluent final outlet. Through the experiment, essential operation parameters and control conditions are given to direct the industrial application of UASB technology when used in wastewater treatment under moderate temperature conditions for urban domestic sewage.