Combined Treating Method Of Urban Sewage By Biofilm Reactor And Zeolite-microwave Radiation Process

With the concern of the water quantity, water characteristics and the discharge properties of the urban sewage, all sorts of advantages and disadvantages of wastewater treating process were compared and analyzed. It was selected that the biofilm was to be the main, microwave enhanced adsorption to be the auxiliary technological process as the efficient method for the treatment of urban sewage. The main existing urban sewage treatment method and biological membrane technology in the present situation of the application of environmental protection were reviewed, and the principle and characters of the biofilm reactor and microwave technology were explained in this paper. Focused on the experiment of biofilm reactor for treating the urban sewage, a few studies have been done, and based on this work it was proposed that the utilization of zeolite-microwave radiation in treating the urban sewage for the second time, making the quality of discharged water meet the pollutants criterion of urban and town sewage treatment plant. The main research contents and drawn conclusions were shown below.Experiments were divided into two parts, the first part was the combination of net-like rotating biological contactor and oxidation of biological contact process in treating the urban sewage, the resource was the discharged septic tank water from Liaoning environmental science research academy.In the course of testing, the effects of biofilm reactor for treating the urban sewage was examined by focusing on the elements e.g. HRT, disc rotating speed, the gas and water ratio in the biological contact oxidation tank etc. Under the optimum Process parameters, i.e. HRT=9h, rotating disc speed12r/min, gas and water ratio4:1, the removal efficiency of CODCr reached84.3%, discharged water concentration range of CODCr was40～50mg/L, it implied that this reactor worked well on the removal efficiency of CODCr. It have reacheed the first level A standard in discharged pollutants of urban and town sewage treatment plant (GB18918-2002). The second part was the sewage treated by the zeolite-microwave radiation process after the treatment of the biofilm reactor. During this stage, experiments focused on the synthetic wastewater treated by the biofilm reactor. The zeolite-microwave radiation process in the removal of ammonia-nitrogen in the water was discussed, intending to decrease the concentration of ammonia-nitrogen furthermore, making it meet the discharge standard. The results showed:the removal efficiency of ammonia-nitrogen of each factor orders as follows:the mass of zeolite> the microwave time> the adsorption time> the power of microwave. When controlling the power of microwave560W, radiation time five minites, mass of zeolite2.5g/100mL, adsorption time seven minites, the concentration of ammonia-nitrogen in the urban sewage effluent droped to below5mg/L. Meanwhile, the concentrations of CODCr also decreaseed to a certain level.It have already meet the removal efficiency of ammonia-nitrogen required in the pollutants discharging standard of urban sewage.