IBM produces multilayered circuit boards in its north Austin plant. Aqueous baths and rinse water are processed at a pretreatment facility where acidity is neutralized and dissolved copper is removed prior to discharge into the sanitary sewer for further treatment at a POTW (Publicly Owned Treatment Works). In 1994 147,000,000 gallons were treated. In an effort to reduce water consumption, a team of environmental, facility and manufacturing engineers was assembled to find uses for the relatively clean wastewater from selected operations. The most likely destination for the water was the cooling tower, which used 101,000,000 gallons in 1994.
The team determined that there were several mechanical cleaning operations in the manufacturing process which required large quantities of fresh water for rinsing. The cleanliness of the product after these cleaning steps was critical to the next manufacturing step. The rinse water from these processes contained little or no dissolved metals.
In 1995, IBM segregated used rinse water from the wastewater used in manufacturing operations that contained dissolved metals and required further treatment. The used rinse water, on the other hand, contained only traces of dissolved metals and already met sanitary sewer pretreatment standards. This segregated rinse water was collected and fed into the cooling towers, replacing a portion of the fresh water being fed to the cooling tower.
Water collected for reuse has averaged 3,350,000 gallons per month for the first three months of operation.
Details of Reductions
Additional Information :
The project cost approximately $85,000 to implement. At the rate of 3,350,000 gallons a month the annual cost savings on the project will be $210,000.
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