Research On Operation Optimization Of Integrated Household Wastewater Treatment Equipment In Rural Areas

With the advancement of beautiful rural construction and the implementation of toilet reform in rural areas,the application rate of rural flush toilets has risen dramatically.The resulting increase in the amount of sewage in toilets has made it impossible to ignore the situation of rural water pollution.However,due to the decentralized and direct-discharge characteristics of sewage in rural areas,and the limited economic funds in rural areas,the sewage treatment plants used in cities are not suitable for the treatment of rural toilets and domestic sewage.Therefore,this project focuses on the rural household combined use type integrated sewage treatment equipment developed by the 12 th Five-Year National Science and Technology Support Program,and has conducted optimization research on equipment operation.This paper takes the assembled and integrated wastewater treatment equipment as the research object,and analyzes the problem of sewage treatment caused by the warming of the equipment through one year's test data.The data shows that the COD,The removal rates of ammonia nitrogen,SS,and BOD were only 22%,15%,39%,and 29%.The treatment efficiency was low,and the emission concentration was far from the standard.Through data analysis,the cause of the equipment problem was found mainly due to the sludge swelling caused by excessive influent concentration and high impact load at low temperature.Sludge swelling is a common problem in the sewage treatment process.Sludge swelling refers to the phenomenon that the sludge structure is extremely loose,and the volume is increased and floated.It is difficult to affect the quality of effluent water due to sedimentation and separation.Based on this reason,several solutions are proposed.Finally,the method of selecting and adjusting the pool before equipment is compared and analyzed for optimization.After optimization,the sewage treatment equipment was put into use after being processed.For comparative analysis,the test address was selected among the households with the same frequency as those used for the optimization.This study mainly studied the startup of the optimized equipment and the best operating parameters.The start-up of the equipment isactivated by selecting the sludge inoculation method.By inoculating the mature activated sludge that has been domesticated,the sludge system can be rapidly established,which is favorable to the formation of biofilms in the anaerobic tank and the aerobic tank.Through comparative analysis of the treatment effect of the equipment under different hydraulic residence time,the optimal hydraulic retention time was determined to be 12 h.Through the theoretical analysis,summarizing the experience and comparative analysis of the processing data of different reflux ratios,the optimum reflux ratio was determined to be 200%;By consulting the data and summarizing the experience,it was determined that the dissolved oxygen concentration of the best aerobic tank was about 2.5 mg/L.The optimized equipment operates normally under the optimal operating parameters,and the treatment effect of the equipment at low temperatures and warming temperatures is studied.Through experimental analysis,the problem of high concentration of influent water at low temperature has been solved.The average influent concentration of COD,ammonia nitrogen,SS,and BOD from the winter of 2016 was 1038.9 mg/L,268.7 mg/L,and 525.3mg/L.,519.3mg/L reduced to 211.6mg/L,42.5mg/L,191mg/L,130.9mg/L,most of the influent reached the equipment design water level.Note that the adjustment tank in front of the equipment can obviously regulate the influent water quality and impact load of the equipment,which helps solve the problem of sludge swelling that will occur in the future.The treatment of the optimized equipment after warming has been studied.After analyzing and summarizing the test data,it can be seen that the treatment efficiency of the equipment after the temperature has warmed up in 2018 continues to be highly efficient.The average treatment rates of COD,ammonia nitrogen,SS,and BOD reached 84.6%,87.2%,95.4%,and 92.5%,and the average export concentrations reached 38.6 mg/L,6.68 mg/L,15.1mg/L,and 15.3 mg/L,respectively.It has reached Level 1 B of the Standard for Discharge of Pollutants from Urban Wastewater Treatment Plants(GB 18918-2002).After the aeration of the aerobic tank was improved,the removal rate of ammonia in the aerobic tank was increased from 18.8% to 31% of the total removal rate.After this experiment,it was proved that the optimization and improvement of the equipment solved the problem of sludge bulking of the original equipment,and the removal effect of the aerobic tank was enhanced,achieving the purpose of optimization.In this study,the optimization of the combined integrated sewage treatment equipment is mainly to increase the adjustment tank before the equipment,and the aerobic tank to increase the aeration.The combination of the adjustment pool and equipment installation can also be separated from the equipment,which facilitates the management and cleaning of the adjustment pool.If there is a problem in the adjustment of water in the tank,the problem can also be controlled in the adjustment tank,without affecting the sewage treatment of the equipment.The operation will not affect the biological activity of the equipment.The success of this optimization has important implications for the promotion of integrated sewage treatment equipment in rural areas,which can effectively alleviate the pollution of rural water environment.