Water’s rising tide
Once an afterthought, water management is emerging as an important operational component in food and beverage production, a visible testament to sustainable efforts but also a critical element in a plant’s continuing viability.
Water use also is making food companies more receptive to new approaches to old problems. In the process, organizations are discovering that an effective water management program extends far beyond usage metering and can deliver many operational benefits.
Odor mitigation is an example. Capacity expansion at Indiana Packers Corp. (IPC) meant more maintenance for the wet air scrubbers servicing the company’s rendering operations. Water consumption for cleaning alone topped 35,000 gallons a week, and the cost of caustic chemicals was increasing, according to Paul Gomes, regulatory compliance engineer at the Delphi, IN pork processor. Operating the scrubbers also required weekly use of 900 lbs. of chlorine gas, “an extremely hazardous material,” Gomes notes. That made Gomes receptive to an alternative approach that relies on enzymes and biodegradable surfactants to clean the scrubbers and ensure they mitigate emissions of odors and volatile organic compounds. In December 2009, IPC became one of the first food companies to deploy ReNew technology from Diversey Inc.
Instead of chlorine gas and sodium bromide to oxidize buildup on the scrubber media, the system injects enzymes and surfactants through a manifold while the scrubbers are in use. The injections are regulated by sensors that monitor the chemistry of water circulating through the scrubbers. In the process, they prevent grease buildup, eliminating the need for weekly cleaning.
Since the IPC project, ReNew has been applied at several other food plants and in different applications, reports Mike Gruver, sales manager for the ReNew portfolio for Sturtevant, WI-based Diversey (the firm was acquired last year by Air Products and Chemicals Inc.). “The right enzymes and good process management with the appropriate equipment” are important, he cautions, but the technology can mitigate odors in a variety of applications. Chemists are experimenting with enzymes that could speed up the breakdown of VOCs and noxious odors from waste lagoons at livestock operations.
Environmental directors at food companies are embracing the technology, says Gruver, though there is resistance from air permit issuers who “don’t understand the fundamentals of the chemistry.” At IPC, the technology actually reduced the time and expense of regulatory compliance and lowered scrubber operating costs by about 25 percent. It also has improved rendering’s odor profile. But the company has made water conservation priority, and the technology delivers on that front.
“For us, the water savings were a driver,” Gomes flatly states. Including IPC, plants using ReNew conserved more than 30 million gallons of water last year, Gruver calculates.
IPC is not alone in making water management an operations priority. The commitment to conservation is most evident at publicly traded companies, many of which are validating their sustainability programs with public disclosures of the water and energy savings they are realizing. Hormel Foods’ most recent corporate responsibility report notes water consumption per pound of finished goods was down 11.1 percent network-wide in 2010 compared to 2006, exceeding a reduction goal of 10 percent by 2011. Some of Hormel’s 39 plants did considerably better, including the Nevada, IA refrigerated-foods facility (24 percent less water use in a two-year period) and the Dubuque, IA shelf-stable foods site, which began production in January 2010 and immediately realized at least a 25 percent reduction in water consumption compared to sites producing the same shelf-stable products.
Irrigation-free landscaping, reuse of boiler blowdown water for toilet flushing and other initiatives nibble at conservation. But process changes have a much larger impact on water management (see “Fabulous Food Plant,” Food Engineering, December 2011). A water-bath system for canned chicken was replaced with high-efficiency ovens that cook the meat faster, use less energy and eliminate water from the process. An elaborate piping and storage infrastructure was built to conserve both energy and water. An element of the system is tied to product cooling. At the end of a retort batch, cold water cools the containers and then is routed through a diversion valve to a heat exchanger. Some of the now-hot water is retained for use in the next batch, while the rest is either used immediately or stored in a 200,000-gallon tank for future use.
The spray retorts in Dubuque are inherently more efficient than the saturated-steam units that account for much of the industry’s installed base, notes Greg Jacob, general manager of Covington, LA-based Allpax Products Inc. To help owners of older retorts meet their sustainability objectives, Allpax engineered a heat and water recovery system that captures steam used in the come-up, vent-open stage that begins the retort cycle.