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METHODS FOR IMPROVEMENT OF TRICKLING FILTER PLANT PERFORMANCE. PART II. CHEMICAL ADDITION
Citation:
Brown, J. AND L. Little. METHODS FOR IMPROVEMENT OF TRICKLING FILTER PLANT PERFORMANCE. PART II. CHEMICAL ADDITION. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-77/012 (NTIS PB266424), 1977.
Description:
An experimental program to explore potential methods for removing phosphorus and generally enhancing trickling filter plant performance was conducted at the Mason Farm Wastewater Treatment Plant, Chapel Hill, North Carolina. Preliminary investigations included jar testing with several coagulants and coagulant aids and pilot studies to determine the effect of the point of alum addition on phosphorus removal. Follow-up full-scale studies utilized the Chapel Hill high-rate trickling filter plant which consists of two parallel identical main-stream trains. From January 25 through October 6, 1972, alum was added to the influent of one final clarifier. Alum dosage and influent flow rates to the dosed train were varied and phosphorus removal, general plant performance, sludge production, and sludge digestion performance were monitored. Alum addition effectively removed phosphorus and enhanced overall plant performance. Optimization of alum precipitation will require a flow-paced alum feed system, restriction of average dry weather final settling tank surface loadings to 20.4 cu m/day/sq m (500 gpd/sq ft), and inclusion of tertiary fine solids removal facilities. Alum sludge decreased the alkalinity and pH in the primary anaerobic digester and led to liquid/solids separation problems in the secondary digester. Separate facilities may be necessary for handling alum-humus sludge from the final settling tank.