The Duckwall Pooley Fruit Co. is one of the largest fruit packagers in the Hood River Valley in Oregon, packing approximately 1.8 million bushels of pears annually. To improve its operations and lower its costs, the company implemented new measures to optimize the rinse water usage in the pear packaging line. After packaging the fruit, collected water is chlorinated for disinfection and treated with coconut shell based activated carbon for residual chlorine removal.
Although reducing the plant‘s water requirement, the water contained residual sediment, pear skin and fruit, which caused bioactivity on the activated carbon media. Sulfur compounds in the water were reduced and formed hydrogen sulfide (H2S), an undesirable “rotten egg“ odor which impacted the packaging plant and facility workers.
Solution
To address the H2S formation issue, the customer contacted Evoqua Water Technologies, which recommended the use of its new AquaCarb 1240CAT catalytic carbon. Catalytic carbon promotes the oxidation of any H2S in water to non-odorous, harmless sulfur species.
To pilot test the solution, the customer purchased Evoqua's AquaScrub 200 drum adsorber, containing 200 lb of AquaCarb 1240CAT catlytic carbon for two weeks. A slip stream of effluent water from the existing Evoqua PV 1000 carbon adsorbers was run through the drum adsorber. Based on the results of this study, the customer elected to switch to the catalytic carbon as a final polish step after initial GAC treatment for chlorine reduction.
Results
In July 2010, Evoqua Water Technologies performed a turnkey exchange of the existing carbon beds, placing 1,000 lb of AquaCarb 1230C coconut shell carbon in the lead adsorber for residual chlorine removal, and 1,000 lb of AquaCarb 1240CAT catalytic carbon in the lag adsorber for treatment of H2S. The results have been exceptional with no H2S issues occurring in the facility, improving the work environment and eliminating worker complaints.
