Wastewater Ion Exchange Removes Heavy Metals From Petcoke Leachate

Challenge

Petcoke, a byproduct of petroleum refining, consists largely of carbon and ash residuals from crude oil processing. Depending on the source of the crude, the ash in petcoke will contain low to significant concentrations of nickel, vanadium, iron and other metals.

Evoqua Water Technologies was contacted by a California business that accumulates, stores and ships petroleum coke to its customers worldwide. The petcoke at this customer's site was originally stored in uncovered concrete vaults. During a storm, the rainwater would percolate through the petcoke, leaching nickel and vanadium from the ash in concentrations higher than discharge limits. The customer contacted Evoqua to find a reliable, straight-forward treatment method to remove these metals from accumulated rainwater.

Solution

Evoqua's solution features our wastewater ion exchange (WWIX) service. Wastewater ion exchange is a service-based option which utilizes ion exchange resins and other medias selected to remove specific ionic contaminants from groundwater, industrial wastewater, and process water for recycle. DOT approved vessels containing the selected resin or media treat the water until the capacity is reached. Once exhausted, the WWIX vessels are removed and replaced with fresh, DOT-compliant vessels and returned to service. Exhausted vessels are returned to our processing facility where the contaminants are removed from the media/resin.

The WWIX system supplied to the customer consists of two 30-cubic feet anion resin vessels in lead-lag configuration, followed by two 30-cubic feet vessels of selective cation or strong acid cation resin, also in lead-lag configuration. The anion resin targets the vanadium while the cation removes nickel.

Results

Once the existing volume of rainwater was treated and discharged, the customer was able to implement a smaller WWIX system for periodic maintenance of water.

Evoqua provided a fast, reliable treatment system that can be expanded or in this case, reduced as the customer's needs change. Off Site regeneration at Evoqua RCRA facility provides the customer with an advantage of simple operation with compliance to all RCRA regulations while hazardous metals are recovered.