Challenge

Evoqua was approached by a Massachusetts auto auction facility for assistance in meeting discharge requirements for zinc to the Publicly Owned Treatment Works (POTW). Effluent from the facility fluctuated from 6–10 ppm, significantly above the required 1 ppm limit. Additionally, this waste stream contained surfactants and oil which was difficult to treat with a typical ion exchange media.

After consultation and process review with the Evoqua technical staff, the facility sent a representative sample of the raw wastewater to the Evoqua testing laboratory for a complete analytical characterization and treatability study. Bench-scale testing indicated that our SCU™ heavy metal removal media​ successfully lowered the concentration below the required limits. Additionally, particulate filtration and oil/grease removal was required as additional processing steps to prevent fouling of the metal removal media.

Solution

The Evoqua full-scale treatment solution included pre/post filtration and oil removal media followed by SCU metals removal media in a lead/lag arrangement to achieve the treatment goal. When the media capacity is exhausted, Evoqua local service technicians remove spent media/vessels from the site and replace them with fresh tanks containing new media. The vessels are transported to our company owned RCRA permitted and licensed TDSF treatment facility for compliant treatment and recovery of metals. The system's modular design allows for easy exchange and service with minimal disruption to daily operation.

Results

The Evoqua service-based solution provided a rapid treatment response without requiring the customer to invest additional capital (or time) to achieve their discharge goals. The Evoqua technical services evaluated the source water and provided a complete solution for treatment of the waste stream. The exchange service at Evoqua eliminated the need for on-site storage of treatment chemicals for improved site and personnel safety. Removal of the contaminant off-site also eliminated the potential for recontamination.