Food Producer Practices P2 and Saves Over $200,000 a Year
In 1996, Golden Valley Microwave Foods (GVMF) of Edina was facing some potential cost increases for SAC and wastewater strength charges. Rather than pay the price and continue business as usual, the company decided to take a close look at its plant processes to find ways to optimize the systems and lower costs. The final results are cost savings of over $200,000 a year!
GVMF accomplished this by focusing on three areas. The first area was the Dissolved Air Floatation (DAF) system. Polymers were changed, a flocculent was added, and some mechanical modifications were made to the system in order to optimize its efficiency. The results are increased solids removal and lower COD and TSS levels in the wastewater discharge. However, with the increase in solids removal, comes an increase in solid waste handling. GVMF switched to all GRAS (Generally Regarded As Safe) products and can now add the solid waste to the waste food bin. The waste is sent out as animal feed and solid waste disposal costs have been reduced significantly.
At the same time GVMF was working on its treatment system, the company focused their attention on the potato processing operations, which contribute the majority of the volume and loading to the DAF. GVMF first controlled the incoming water to the process. They replaced oversized feed lines with feed lines that would only deliver the required flows. Next, GVMF set up a solids separator system at the end of the potato peeling process. This captures the solids at the source, rather than at the DAF unit, and recycles the clean water back into the peeling process. To further enhance solids removal, the company installed a small two-stage cyclone separator at the end of the potato blanching area. GVMF add a food-contact-approved de-foamer to the discharge water and then returns this water to the peeling process. As a result of these changes, the company went from using 50 gallons of water per minute (gpm) in the potato processing area down to approximately 10 gpm.
GVMF next looked at the air scrubber system. Wastewater from this system also entered the DAF for pH neutralization purposes. The company switched from using sodium hypochlorite in the air scrubber to bromine, which has a much lower pH. This switch allowed the company to reuse scrubber return water as feed for the cooling tower system.
Through enhanced solids removal, water reuse and reduction and chemical substitution, GVMF optimized both its operation processes and wastewater treatment system. By practicing pollution prevention, the company reduced SAC liability, strength charges and permit fees, and eliminated the need for a treatment system up-grade or replacement.
If you have questions regarding pollution prevention opportunities for your facility, please contact the MCES engineer assigned to your permit.