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Title:Evaluation of Ultrafiltration to Recover Aqueous Iron Phosphating/degreasing Bath
Author(s):Lindsey, Timothy C.; Ocker, Alisa G.; Miller, Gary D.; Miller, Michelle C.
Contributor(s):United States. Environmental Protection Agency. Waste Reduction Innovative Technology Evaluation (USEPA EPA WRITE); Illinois. Department of Energy and Natural Resources. Hazardous Waste Research and Information Center (ILENR DENR ENR HWRIC)
Abstract:Pollution prevention efforts targeted the hazardous waste generated from a 5000-gallon iron phosphating/degreasing bath used by a metal fabricator to clean and precondition steel parts for painting. With extended use, the buildup of emulsified oil in the bath reduced cleaning and phosphating efficiency. Dragout of oil from the bath into the rinse water also pushed oil and grease levels in the effluent over the allowable limit. When oil in the bath began to sacrifice product quality and effluent levels edged closer to the maximum allowable limit, all 5000 gallons were dumped and replaced. Periodic dumping, about three times each year, resulted in at least 15,000 gallons per year of hazardous waste. Several waste minimization alternatives were considered, and ultrafiltration was selected as the most promising technology to recover and reuse the bath and to reduce the total amount of hazardous waste generated. Ultrafiltration has proven successful in similar industrial applications with alkaline cleaning solutions, but the application of new membrane filtration technology to this acidic, corrosive, high temperature bath was an innovative approach to pollution prevention. This project was carried out in four stages: ( 1 ) initial assessment of the problem and evaluation of alternatives, (2) bench-scale screening of ultrafiltration membrane candidates, (3) pilot-scale study at the Illinois Hazardous Waste Research and Information Center (HWRIC), and (4) full-scale implementation and testing onsite at the company's facility. Full-scale testing integrated the new waste reduction scheme into the facility's production process by applying ultrafiltration directly to the 5000-gallon iron phosphating/degreasing bath. Ultrafiltration successfully removed oil contamination from the bath and returned clean process solution back to the original 5000-gallon tank. Ultrafiltration concentrated the hazardous component down to 10 gallons of oily waste and reduced hazardous waste generation 99.8%. The concentration of oil in the bath was substantially reduced and maintained at acceptable operating levels. Permeate flux rates exhibited excellent performance and were high enough to compete with the constant input of oil from the production line. A significant portion of the unused phosphating agents were also conserved although some surfactant was lost. Product quality tests revealed that quality achieved during the full-scale ultrafiltration study was good for the facility's application. The estimated payback period associated with implementing ultrafiltration was only 6.9 months. Results of this study were used to justify installing a permanent ultrafiltration system and operating practices that would improve product quality.
Issue Date:1994
Publisher:Hazardous Waste Research and Information Center
Series/Report:TR Series (Hazardous Waste Research and Information Center) ; 014
Genre:Technical Report
Sponsor:Prepared for United States Environmental Protection Agency, Waste Reduction Innovative Technology Evaluation (WRITE) Contract No. CR15829
Date Available in IDEALS:2007-09-07

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