A Laboratory Study On The Treatment Of Domestic Wastewater By A Novel Anaerobic Reactor--USSB Reactor

The volume of domestic wastewater is greatly increased with rapid urbanization and water pollution becomes more and more serious. Anaerobic treatment processes have many merits such as consuming less energy, producing low sludge and useful energy etc., so it has been used widely to treat wastewater. With a series of high efficiency anaerobic reactors invented, it is possible to treat low concentrate wastewater at short hydraulic retention time (HRT). Therefore, it is of significance research and application value that domestic wastewater is treated by these anaerobic reactors.The upflow stage sludge bed (USSB) reactor designed on the basis of SMPA is a novel anaerobic reactor. Some research about it has been done at abroad, but there is no research report on the treatment of domestic wastewater by USSB reactor at abroad and home. In this study, a pilot USSB reactor designed and made by us was used to treat domestic wastewater. The start-up of USSB reactor was researched. After the start-up of reactor was finished, the reactor was used to treat domestic wastewater. The operation characteristic at different HRT, kinetics of substrate degradation, microorganism forms from various compartments of reactor and aerobic post-treatment were investigated during domestic wastewater treatment. The aim of this study is to discuss the feasibility of domestic wastewater treatment by USSBreactor and provide some reference with practice application of USSB reactor in the future.The following conclusions can be drawn through the study:(1) when the aerobic and digested mixed sludge were used as seed at mesophilic temperature(35+2C), if the glucose medium concentration water was used as cultivating wastewater, it could shorten the period of the start-up of reactor and the start-up of reactor was successfully finished at short time.(2) During domestic wastewater treatment by USSB reactor, the change of HRT had great effect on the gas production and the COD removal. With the HRT prolonged, they were all increased quickly. The change of HRT had little effect on the SS removal and the VFA. The NH3-N and total phosphorus(TP) of domestic wastewater were not basiclly removed during this process.(3) Compared with the reactor start-up, the microorganism forms in the reactor had great difference during domestic wastwater treatment. After the start-up of reactor had been finished, the microorganism forms had great change in different compartment of the reactor corresponding to different substance. After domestic wastewater treatment was finished, the microorganism forms had almost no change in different compartment of the reactor and they all made up of spherical and filaceous bacterium.(4) A correlative kinetic model of domestic wastewater degradation of the reactor was established. It was expressed: S. = So / (1 - 0.22t) .(5) The COD .. NH3-N and TP could reach high removal efficiency when the anaerobic effluent was treated by an aerobic biological reactor at shot time(3h). The effluent COD NH3-N and TP could meet the Grade I I and II of National Discharge Standards 8978-1996 individually. Therefore, domestic wastewater treatment by USSB anaerobic reactor is feasible. It has wider application on decentralization domestic wastewater treatment.