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Newsletter winter 2002 |
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Site Visit Story—Avoid
a Big SAC
Story: Metal
Treaters, Inc., of St. Paul, a commercial heat treater that
processes a variety of metal parts, added a new line with
water intensive cleaning tanks that increased water use by
4.5 million gallons a year. Following a review by the public
wastewater treatment facility, the company learned it would
need to purchase 66 more Service Availability Charge (SAC)
units—at a one-time cost of nearly $75,900—unless
it reduced water use.
Ed Barcikowski,
metallurgist, called MnTAP for assistance. Randy Cook and
Karl DeWahl, MnTAP engineers, visited Metal Treaters to help
identify opportunities to reduce water use, including filtration
technology and an automatic system to maintain water levels
in rinse tanks.
Results:
Working with an outside vendor, Metal Treaters designed a
portable wastewater filter system to remove contaminants,
allowing the number of batch discharges to be reduced. Drag-out
reduction techniques extended the life of cleaning tanks and
reduced demand for cleaning chemicals. The company also installed
automatic filling systems with timers to maintain water levels
in rinse tanks. Metal Treaters decreased water use by 90 percent,
reducing its SAC to six units, saving $66,000. Additional
savings resulted from lower water and chemical use.
Prevention
Tips: Drag-out
reduction techniques such as allowing for drip time and using
air blow-off and rinse aids will reduce carry over. Add fresh
water in the form of fog or mist to rinse off carry over.
Cover heated tanks between use to reduce evaporation. Use
conductivity sensors to measure contaminant levels and use
an automatic filling system with timers to control water flow
to the tanks.
Request
a visit from a MnTAP engineer or scientist to get suggestions
customized to your operation, call 612.624.1300.
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