Physical-chemical treatment of municipal wastewater

ment of secondary effluents, the product water from granular carbon treatment contained organic materials apparently re sistant to carbon adsorption.1 Addition of chemical clarification to the tertiary treat ment system2 for phosphorus removal eli minated from secondary effluents most of the organics resistant to adsorption and produced water, after carbon adsorption, with residual total organic carbon (toc) concentrations of less than 1 mg/1. The clarification with lime or alum insolubilized the phosphorus and flocculated the col loidal organic and phosphorus materials that were too small to be filtered efficiently and too large to diflFuse into the pores of the carbon granule. A primary effluent, fed to that tertiary treatment system, re vealed that clarification and filtration to re move the colloidal material from the pri mary effluent also produced moderately low residual organic concentrations after carbon adsorption. Recent Studies