Prior to installation of the Enviro-Clean Process, all rinse water was chemically treated to local limits and discharged to the POTW. Large quantities of F006 sludge requiring disposal was generated during the treatment operation. Untreated rinse water showed average concentrations for copper, silver, and cyanide were 1.05 mg/l, 0.27 mg/l, and 6 mg/l, respectively.
LES installed a system designed to process 80 gpm of rinse water. Raw rinse water flows into a 1,000 gallon surge tank where it is aerated and pH adjusted. The water is then pumped through two 2,000 pound specially treated activated carbon absorbers in series where the metals are absorbed and the cyanide destroyed. The system produced an effluent with concentrations of 9 ppb silver and 5 ppb mg/l copper. Cyanide is destructed to non detection levels.
Effluent from the Enviro-Clean process was judged by the client to be of suitable quality to be recycled directly into the rinsing process. Recycle rate averages 35-60 gpm. New water purchases were reduced by 50%. F006 sludge disposal was reduced to zero.
This installation processed over 5,500,000 gallons of water before the initial absorber change out.
Spent carbon, which passes TCLP testing, is shipped via common carrier to LES’ Pittsburgh processing facility. Silver and copper are stripped, electrolytically recovered, and sold to other industries as a metallic product. The carbon is regenerated and returned to the client.
Presented below are actual savings derived from the first year of operation.
| AREA: | SAVINGS (yearly) |
| Water Recycling | $136,752 |
| Sludge Reduction | $68,719 |
| Water Treatment Chemicals | $28,011 |
| TOTAL: | $233,482 |