11 for backwashing the adsorption bed 22 and filtration bed 23 the remaining water from the clear well 24 passes through the disinfection tank 26 and the effluent water conditioner 27 before discharging as the treated effluent 18 the backwash wastewater is sucked by the backwash pumping means 15 through the backwash hood 25 going to a separator 29 the sludge in the filter media free water is settled in a decanting tank 42 by gravity and is discharged as the settled sludge 17 the supernatant 30 is recycled for elimination of a secondary pollution and for water conservation small amount of the settled slit from the open vessel bottom 12 and the settled sludge 17 are transported to a separated process unit for final disposal the unique features of the present invention which have been described are a an in line static mixing means is for chemical mixing and energy saving b the monitor automatically adjusts and optimizes the chemical dosages c the open vessel is a built in aerator flocculator and grit settling chamber for space saving energy saving and high oxidation performance d circular automatic backwash adsorption beds and circular automatic backwash filtration beds remove suspended dissolved colloidal and living substances e backwashing and decanting means have provisions for washwater recycle and filter media recycle and f in line water conditioner polishes the treated effluent accordingly the present invention can treat either water or wastewater and produces no secondary pollution except small volume of sludge still another unique feature.