Ultrafiltration: In-Line Recycling of Multi-Stage Parts Washer Process Fluids

This fact sheet documents the waste reduction measures of a company located in central Illinois that manufactures metal components used in electrical and mechanical support systems. These include conduit, process piping, wiring race ways, and other electrical equipment. The company’s goals were to improve its paint line’s pretreatment cleaning performance and to reduce operating costs. To achieve this, they successfully implemented ultrafiltration membrane technology, which produced significant environmental reductions and savings. The Story This company has utilized ultrafiltration membrane technology since the mid-1990s to recover synthetic metalworking fluid. Though not new to membrane filtration, the company requested ISTC’s assistance to investigate membrane filtration to reclaim its large paint line’s pretreatment process fluids (degreaser, rinse waters and iron phosphate). The pretreatment process consists of a multi-stage wash system comprised of a series of 1,000-2,000 gallon process tanks. Historically, these tanks were dumped, cleaned and recharged on a routine basis, causing line downtime and increased operating costs. Through ultrafiltration, the expectation was to recycle the fluids in situ, thereby extending bath life, reducing labor costs, and chemical costs while improving the line’s cleaning performance. After several months of evaluating membrane compatibility and performance within the varying process chemistries and criteria, the company determined ultrafiltration to be a viable waste minimization solution. Previously disposed fluids could now be recovered. The Results The facility engineer installed ultrafiltration systems throughout the entire pretreatment line: degreaser, phosphate and three post-process rinses. Resultant annual reductions: 1,401,000 gallons water, 825 gallons of specialty chemicals and 1,108 gallons of paint. This resulted in a total annual savings of