- THE MAGAZINE
- FOOD MASTER
Golden Flake Snack Foods (Birmingham, AL) was faced with a tough decision-either come up with a solution to stop escalating municipal wastewater surcharges, or move its 300,000-sq.-ft. snack food processing plant out of the county to stem the rising costs. In 2008, costs had escalated to $100,000 per month in surcharges, with county projections of up to $250,000 per month by 2014.
The Alabama Department of Environmental Management (ADEM) made it clear that if Golden Flake could reach prescribed TSS (total suspended solids), BOD (biochemical oxygen demand), NH3-N (ammonia-nitrogen) and DO (dissolved oxygen) concentrations, it could receive a discharge permit to convey treated effluent directly into a creek that runs along the perimeter of its property, and bypass the Jefferson County sewer system.
The Golden Flake plant manufactures and distributes a full line of snack food items, including potato chips, tortilla chips, puffed corn, corn chips, cheese puffs, cheese curls, onion rings and pork skins. In 2009, Golden Flake’s Birmingham facility processed more than 20 million pounds of snack foods.
Raw snack food wastewater is pumped through vibrating screens that collect 15,000 to 20,000 pounds per week of large food particles. This organic matter is collected and transported upstate to be used as animal feed.
“The wastewater being decanted to the county sewer system had BOD and TSS concentration levels in the thousands, exceeding maximum surcharge levels” says David Jones, Golden Flake executive vice president of operations. “As our surcharges continued to escalate, we began looking for a treatment technology that could not only handle our high-volume peak flows of 350,000gpd, but also produce an effluent that was below ADEM’s maximum allowable discharge concentration limits for BOD, TSS, NH3-N and DO.”
Golden Flake brought in ADI Systems to engineer a solution, which was complicated by the fact the inner-city plant is landlocked. There was no room for site expansion, and little space for a conventional activated-sludge facility. ADI Systems recommended a membrane bioreactor (MBR) system to treat the raw wastewater following the vibrating screens. The ADI-MBR process, based on technology developed by ADI Systems and Kubota Corporation, is a form of activated sludge technology that uses a submerged membrane barrier to perform the liquids/solids separation and reactor biomass retention functions, instead of gravity clarification, which eliminates problems associated with sludge settling and separation.
The new MBR system consistently produces effluent that is lower than the discharge limits set by ADEM. Up to 250 gallons per minute of clean, high-quality effluent is released into Upper Valley Creek, and serves to enhance the downstream riparian environment by improving the oxygenation of the water flow within the small watercourse.
The waste-activated sludge from the MBR system is pumped through an onsite dewatering press to reduce the overall sludge volume to 20,000 pounds per week, which is then trucked upstate for farm fertilization.
For more information:
Graham Brown, ADI Systems Inc., 506-452-7307; firstname.lastname@example.org; www.adisystemsinc.com