Abstract |
Waste waters from a Fortrel Polyester manufacturing plant consisted of organic chemical process wastes, cooling system blowdown, and sanitary wastes from the plant. A water reuse program was instituted which consisted of: (1) pretreatment of cooling waters for removal of heavy metals; (2) in-plant modifications and additions to the existing system to increase treatment plant capacity; and (3) a post treatment system for effluent polishing prior to selected reuse. The final system consisted of: (1) a chromate reduction unit rated at 120 gpm for concentrations of up to 300 mg/l CrO4 and designed for continuous operation; (2) equalization basins having a combined capacity of 195,000 gallons and containing sufficient mixing capacity to prevent short-circuiting and stratification; (3) a plastic media roughing filter consisting of two tiers of poly-vinyl chloride media 10 feet thick and 25 ft in diameter; (4) an aeration basin equipped with 175 hp of aeration and mixing capacity and using 100% recycle of clarifier sludge; (5) a peripheral flow type clarifier; (6) two series connecting polishing ponds; (7) a micro screen or algae screen; (8) a flocculant and/or carbon unit; (9) a sludge pond; and (10) a digester. Chromium was removed from the cooling tower blowdown for $.21 per pound of chromate removed. The plastic media trickling filter, used as a roughing filter, provided 40% BOD removal over a wide range of loading rates. The 0.33 mgd industrial and domestic waste water was treated and reused at a rate of 0.10 mgd for approximately 40 cents/1000 gallons. (WRSIC abstract) |