PILOT STUDY OF THREE STAGE BIOLOGICAL FILTERS FOR NITROGEN REMOVAL AT BINGHAMTON–JOHNSON CITY JOINT SEWAGE TREATMENT PLANT

The Binghamton-Johnson City Joint Sewage Treatment Plant (B-JC JSTP), New York, is under state Consent Order to expand its wastewater treatment facilities to meet effluent limits for discharge to the Susquehanna River, a Chesapeake Bay tributary. A plant upgrade is necessary to increase the primary treatment capacity to treat peak storm weather flows up to 60 mgd. At the same time, the secondary treatment capacity must be increased to a minimum of 35 mgd.A conventional activated sludge expansion would require a significant increase in plant area, not available in the plant's immediate vicinity. A preliminary facility study determined that biological filters would be cost effective in meeting the above treatment objectives and would fit within the existing plant site.To collect site-specific design information, a 5-month pilot study of a three-stage arrangement of biological filters for carbon removal, nitrification, and denitrification was conducted at the B-JC plant. The pilot biological filters and ancillary equipment were provided by Infilco Degremont, Inc.The information obtained from the study assisted in determining the feasible treatment level, impact of peak wet weather flows on treatment efficiency and full-scale design, and the cost effectiveness of the proposed upgrade. Operational data was also collected to estimate biomass production, solids settling characteristics, cold weather nitrification, and treatment of shock TSS, BOD5, and TKN loads.The results of the pilot study demonstrated the ability to achieve final effluent composition of 20 mg BOD5/l, 20 mg TSS/l, and 5 mg total nitrogen/l. Based on the loading criteria established by the pilot study, it was determined that the full-scale expansion would fit within the existing site limits and allow elimination of the peak wet weather bypassing associated with activated sludge.