Tag Archives: Copper

Copper and Nickel Removal

  By Integrated Engineers | March 5, 2009 - 10:21 am | Metals
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Circuit Board Manufacturer

A Circuit Board Manufacturer in southern California was not able to achieve the discharge levels of copper and nickel with their existing system of coagulant, anionic and cationic flocculants and metal precipitant treatment process followed by lamella plate clarification. The previous treatment process developed a settled sludge that had poor shear characteristics and required further coagulant addition to be able to dewater in the filter press. The facility processes 50,000 gal/day and recycles all but 2,500 gal/day, which is discharged to the Los Angeles County Sanitary Sewer system. Their target was 1.0 ppm and they were achieving 0.5 to 1.5 ppmin a sporadic manner.

Before and After Floccin

Before and After Floccin

Integrated Engineers treated the water with IE-061 (a metal precipitant) to a set point pH of 10.2 and flocked with Floccin D. Samples were analyzed using current EPA methods on an ICP.

Component

Untreated

Previous Treatment

Floccin
Treatment

Copper

156 ppm

0.5-1.5 ppm

0.3 ppm

Nickel

210 ppm

0.6-1.5 ppm

0.4 ppm

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Copper and Zinc Removal

  By Integrated Engineers | March 5, 2009 - 9:37 am | Metals
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Ammunitions Manufacturing

An ammunition manufacturing facility was having problems removing copper and zinc from their 900 gpm wastewater system. The process used lime to raise the pH from 1.5 to 10, sodium carbamate for a metal precipitant, and an anionic flocculant to increase the flock size and get the solids to settle in the clarifier. Current chemical costs are estimated at $225,000/year with a significant amount of sludge addition from the lime, thereby adding to the operational costs due to the sludge being a hazardous waste. Integrated Engineers, Inc. tested the wastewater and found that adding caustic to a pH of 10.0 and Floccin D worked as well as the current chemistry. The Floccin D dosage was 0.35 grams in 800 ml (280 ppm). The third sample shown below is with 160 ppm of IE-061. The test results are shown below:

Before and After Floccin

Before and After Floccin

In addition, by switching from lime to caustic the reduction in solids generation would be a significant cost reduction. At peak flow the amount of lime required (17.3 lbs./1,000 gallons) generates 7,450 pounds of 100% dry solids. In a normally dry cake the solids are 30%, therefore they were generating nearly 25,000 lbs. of sludge per day that was hazardous and expensive to dispose of in a landfill. Based on a disposal cost of $35/ton, the cost reduction due to the lime addition to the sludge would be $450 per day ($160,000/year).

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