Wastewater pretreatment system: It is a system for separating precipitated solids from a waste stream. The system consists of primary units which together remove the heavy metals from a wastewater system.
The wastewater is collected in the pH adjust tank. When the tank reaches the permissive level, process pumps feed water from the adjust tank through the cells. Ferrous ion is added in the cells. The stream leaving the cell is now essentially a water solution containing metal hydroxides which can be precipitated from the water. The water is then passed to a retention tank were the solids from the high zinc influent are removed. Polymer is added to overflow from the degassing tank and enters the flash mixing chamber of the Clarifier. From the flash mixing chamber it passes to the flocculating chamber. The liquid flows out through the weir at the top of the Clarifier and is discharged. The slurry transfer pump pulls the solids from the cone of the Clarifier and pumps them to the slurry holding tank. When the slurry holding tank is half full, the filter press system is activated. The slurry pump pumps the solids through the filter press and a thick cake forms in the press. The outflow water from the press is returned to the equalization tank. The solids in the filter press are removed from the press and disposed of by EPA standards.
After treatment, results from operating units show heavy metal levels well within EPA specifications.
Details of Reductions
Additional Information :
Purchase and installation cost: $200,000. Approximate annual savings: $60,000.
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