Recycling hexavalent chromium rinse waters to meet sustainability goals

Challenge

A large midwest aerospace structure manufacturer reached out to Evoqua to help them implement sustainability steps to reduce their overall water usage, decrease their exposure to the local publicly owned treatment works (POTW) and provide a high-quality/low total dissolved solids (TDS) final rinse to meet stringent end-user quality requirements.

Solution

Evoqua evaluated the customer’s entire finishing process (pre-clean, alodine, chromating, passivation, seals) and gathered numerous samples from individual rinses to determine the most effective treatment system design.  Evoqua performed lab analyses, process evaluation, treatability studies and supplied an onsite demonstration WWIX system prior to the engineering and installation of a full-scale 100 gpm WWIX system for recycling the chromium-containing rinses. Evoqua also supplied a reverse osmosis (RO) system to reduce the TDS loading of their incoming city water, used for rinse water makeup, to extend WWIX resin capacity.

Results

This aerospace customer is able to recycle a significant volume of wastewater which would otherwise have been routed for discharge to the sewer. Evoqua’s WWIX system achieved the customer’s goals of overall water-usage reduction, saving on both incoming water usage and sewer discharge costs and met the high-quality rinse standard required for their manufacturing of critical aerospace components. 

Additionally, the WWIX tank exchange service and offsite regeneration of the WWIX resins at Evoqua’s RCRA-permitted facility provides the customer with the advantages of a) simple system operation, b) maintaining hazardous waste regulatory compliance and c) recovery of the hazardous metals to minimize their liability and further their sustainability objectives.