Liquid purification or separation – Processes – Making an insoluble substance or accreting suspended...
Patent
1985-05-10
1987-11-10
Hruskoci, Peter
Liquid purification or separation
Processes
Making an insoluble substance or accreting suspended...
210724, 210726, 210913, 423 55, C02F 152, C02F 170
Patent
active
047056398
ABSTRACT:
The present invention involves a treatment technique for drastically reducing the volume of hazardous sludge generated by the chemical reduction of chromium contaminants and the precipitation of heavy metal contaminants from contaminated electroplating wastewater. The wastewater is first adjusted to a pH of from about 8 to 10 and then treated with sodium sulfide to provide sulfide ions to effect precipitation of heavy metal contaminants followed by treatment with ferrous sulfate or ferrous chloride to provide ferrous ions to chemically reduce the hexavalent chromium to its trivalent state. This method produces approximately one-fourth the sludge generated by the previously known acidic reaction treatment using only ferrous sulfide.
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Collier Stanton E.
Hruskoci Peter
O'Brien William J.
Singer Donald J.
The United States of America as represented by the Secretary of
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