Accordingtothesourceofsewage,sewagecanbedefinedasthedischargeofgroundwaterfromresidential,institutional,commercialorindustrialareas.Aliquidorwatermixedwithwaste,suchassurfacewaterorsnowstorms.Therearemanytypesofsewa

At present, China's urban waste is growing at an annual rate of 8% to 9%, and the annual per capita urban household waste production is about 450 to 500kg. Although China's urban solid waste treatment has achieved certain

Humanactivitieswillmakealargenumberofindustrial,agriculturalanddomesticwasteintothewater,sothatthewaterispolluted.Atpresent,morethan420billioncubicmetersofsewagearedischargedintorivers,lakesandseasaroundtheworldev