Research On Rural Household Integrated Wastewater Treatment Equipment Based On MSL System

Rural water pollution is a serious problem in China.Compared with urban sewage treatment,rural sewage treatment has the problem of many pollution sources and scattered,forming a phenomenon of high discharge and difficult treatment,untreated sewage is discharged into the natural water bodies in rural areas,leading to water quality deterioration,causing great harm to the ecological environment,the search for decentralized sewage treatment technology applicable to China’s rural areas is the main problem faced.Multi-soil-layering（MSL）system has become a preferred technology for decentralized wastewater treatment at this stage because of its excellent economic and environmental benefits and has been applied to the treatment of domestic wastewater,restaurant wastewater,livestock wastewater,and polluted river water,but there are still problems such as single structure,poor denitrification effect and easy clogging of soil pores.However,there are still problems such as single structure,poor nitrogen removal,and easy clogging of soil pores.In this paper,an integrated wastewater treatment equipment based on MSL system is established to address the current shortcomings of MSL system,it aims to apply the equipment to the wastewater treatment in rural areas to meet the needs of decentralized wastewater treatment in rural areas in China.The research contents and main results of this paper are as follows.（1）The design of integrated wastewater treatment equipment based on MSL system.The equipment mainly includes pretreatment system,water distribution system,treatment technology system,aeration system,and de-bacterization system.The pretreatment system adopts a combination of mechanical separation and sedimentation and fermentation to regulate the water volume,retain large particles in the sewage,degrade pollutants and prevent the system from clogging;the water distribution system evenly distributes the water from the pretreatment system to the treatment system through a submersible pump,the flow direction of the sewage to be treated in the inlet pipe is from bottom to top,and the flow direction in the treatment technology system is from top to bottom vertical flow The role of the bacteria removal system is to collect the water from the treatment technology system and remove the harmful bacteria in the water,and finally discharge the treated water.（2）The control system design of integrated wastewater treatment equipment based on MSL system.Mainly through the design of a reasonable program to drive the hardware in the system,to achieve the collection function of information such as the amount of water treated,treatment process,treatment cycle of the equipment,and through the collected information to control the work of solid-liquid separation motor,submersible pump,air pump,ultraviolet overpressure,electric valve,and other actuating devices.（3）The operation effect test of integrated sewage treatment equipment based on MSL system.The optimal operation parameters were determined by 150 days of equipment operation test.The surface hydraulic loading rate（HLR）was controlled at1000 L·m^-2·d^-1,and the gas-water ratio was 4:1.Under this operation condition,the average concentrations of COD,NH₃-N,TN,TP and SS in the effluent were 106.5 mg·L^-1,7.4 mg·L^-1,13.9 mg·L^-1,0.12 mg·L^-1 and 18.6 mg·L^-1,respectively,and the corresponding removal rates were 85.3%,82%,72.5%,96%and 85%,respectively.The effluent quality indicators can meet the emission requirements specified in the Discharge Standard of Water Pollutants for Rural Domestic Sewage Treatment Facilities（DB 50/848-2021）.（4）Application case analysis of integrated wastewater treatment equipment based on MSL system.This paper selects an ordinary farmer in Liuyin Town,Beibei District,Chongqing as the research object,examines the treatment capacity of the integrated wastewater treatment equipment based on MSL system for the actual domestic wastewater of the farmer and carries out a comprehensive analysis with the actual treatment effect of the equipment,the construction and operation cost,and the form of subsequent promotion and application.The results of the paper show that the MSL system-based integrated wastewater treatment equipment can be automatically controlled,has stable operation,has good pollutant removal effect and has certain economic and environmental benefits,and is suitable for promotion in rural areas in China.