Study On Multi-media Filtration Treatment Technology Of Grey Water In Northwest Rural Area

The northwest region is arid and short of water,with a relatively low level of economic development.The treatment rate of rural domestic sewage is far lower than the national sewage treatment level.Carrying out rural water environment treatment in the northwest region is of great significance for building an ecologically livable and beautiful countryside.This study focuses on the gray water in rural areas of northwest China.By analyzing the characteristics of gray water discharge and water quality,multi-media filtration technology is selected to treat rural domestic gray water,and the effluent is used for irrigation of farmland resources.The results of this study can effectively prevent environmental pollution caused by scattered gray water in rural areas,and verify the feasibility of treating and reusing gray water in rural areas of northwest China.The main research content is as follows: 1)Based on the filter medium selection and composite experiment,a composite medium composed of corn stalks,ceramic particles,and activated carbon was selected as the filter medium.2)Through experimental research on the influencing factors during the filtration process,it was found that the optimal filtration rate for multi-media filtration technology is 0.26 m/h;The optimal medium ratio is corn stem: ceramic particle: activated carbon medium ratio of 1.5:2:0.5;The treatment concentration limits for influent COD,SS,and LAS are 300 mg/L,300 mg/L,and 30 mg/L,respectively;The minimum temperature for the experiment is 2 ℃.Based on the experimental results of influencing factors,an integrated multi medium filtration equipment was designed and constructed,which operated stably for 57 days and met the dry farming standard of farmland irrigation water quality standard(GB5084-2021).3)The mechanism of pollutant removal from gray water by filter media was analyzed using instruments such as SEM-EDS,XRD,and FTIR.The results of SEM-EDS showed that the surface of the filter media had adsorbed particulate pollutants from the water;The XRD results indicate that corn stalks and activated carbon adsorb water pollutants on the surface,while ceramic particles adsorb water pollutants on both the surface and interlayer;The FTIR results indicate that corn stems promote adsorption through hydrogen bonding and π-πinteractions;Ceramic particles promote adsorption through hydrogen bonding and electrostatic interactions;Activated carbon promotes adsorption through hydrogen bonding and hydrophobic interactions.