Waste's Silver Lining

Oct. 30, 2014
Food companies are beginning to look at liquid and solid wastes as opportunities and not simply costs.

The wastewater and solid waste generated in food production has to be dealt with, but they typically are disposed of as expediently as possible.

Food Processing’s annual manufacturing trends survey bears this out. Asked to prioritize 11 manufacturing issues, readers ranked wastewater and solid-waste management dead last, with one-third of respondents rating them either 10th or 11th in importance and fewer than 1 in 17 indicating they are top priorities.

Astute business people understand the drag on profitability created by waste. Shown reliable numbers on the cost and missed revenue opportunities in the waste stream, they are happy to change course — provided, of course, that it doesn’t detract from the primary mission of filling orders for finished goods.

A case in point is protein recovery from chicken byproducts going to rendering. Poultry processors typically place two screens, one with a 0.08-in. mesh and the second at 0.02 in., to salvage saleable fines from the offal room. Recovery rates would be higher with a finer mesh, but sourcing and installing a screen and maintaining it are distractions.

Low pressure, reverse-osmosis technology was the final piece in a process-water recovery system that enabled Frito-Lay'ss Casa Grande, Ariz., plant reuse three quarters of the water coming into the plant.

Engineers at Lyco Manufacturing Inc. in Columbus, Wis., have tried to fabricate a solution “as long as we’ve been building screens,” about 20 years, says Jeff Zittel, vice president-technology applications. Based on a field test of their micro drum screen, they believe they found a solution.

The screen’s 0.008-in. mesh was able to recover about 9 lbs. per minute at a 2,000 gal. a minute flow rate in the trial. Assuming 16 hours a day operation and 5 cents per lb. for protein, the drum should recover $450 a day worth of meat. To prevent clogging, a continuous flow of filtered water is backflushed, providing “a self-contained CIP system,” Zittel maintains.

“We played with multiple types of interwoven and woven mesh and different wedge wire before finding something that works,” he says. A similar system is on the market, but limited flow rates and “manual interventions” have discouraged most poultry processors from deploying it.

Capital also is an issue: Even with protein, ROI takes about 1½ years. But fewer dissolved air flotation chemicals and avoidance of other downstream treatment costs are other advantages, and Zittel says there is strong interest among carrot and potato processors in recovering saleable fines from their processes.

Mining value from liquid and solid waste is a low priority for most food and beverage processors, as Food Processing’s manufacturing survey confirms, but whether it’s a reaction to costly disposal requirements or a proactive decision to attack waste, companies are finding treasure in unexpected places

Energy harvesting

Cost avoidance drives many of the industry’s wastewater treatment projects, though mandated reductions in phosphorous and other minerals can add urgency to upgrades. Surcharges for exceeding limits for total suspended solids, biological oxygen demand, chemical oxygen demand and other metrics are changing the payback calculation for additional treatment steps at many production sites. At the same time, declining technology costs and more “user friendly” systems are providing more options for food companies.

An example is the membrane bioreactor (MBR), once deployed almost exclusively in municipal treatment plants. Once viewed as too maintenance-intensive and costly for industrial applications, MBR increasingly is part of the solution for process wastewater.

In a recent project proposal, ADI Systems Inc. presented a conventional treatment and MBR, “and they were fairly close in cost,” notes Scott Christian, vice president-business development at the Oromocto, New Brunswick, engineering firm. Effluent quality was superior with MBR, and a smaller footprint and greater load capacity also favored MBR.

Anaerobic MBR is ADI’s signature solution, and processors increasingly opt for that technology and harvest the resulting methane to fire boilers or power a genset for electricity. In a recent upgrade at Kellogg Co.’s Pikeville plant in Kimper, Ky., ADI incorporated anaerobic MBR followed by aerobic polishing before discharge to a nearby creek. Christian believes the combination system is the first of its kind in North America.

When he began his career as an engineer specializing in dairy waste, “I asked, ‘Why are we doing aerobic treatment when you get so much more bang for your buck from anaerobic?' ” recalls Henry Probst, a third-generation partner at the Probst Group LLC, Brookfield, Wis. “The answer was, ‘Everybody’s afraid of (anaerobic).' ”

Fear has subsided, and he reports more food companies are opting for the greater flexibility, energy efficiency and value provided by anaerobic solutions.

Technology such as this membrane bioreactor is being used more frequently in food processing as manufacturers react to higher wastewater surcharges and stricter discharge limits. Photo: Altech Technology Systems Inc.

Membranes and UV disinfection also open the possibility of reusing treated water for CIP, boiler feed and other purposes, he adds.

Water reuse is becoming more common, agrees Charles McCloskey, vice president and general manager-industrial projects at Alpharetta, Ga.-based Evoqua Water Technologies LLC, a Siemens business unit sold to a private equity firm earlier this year. But reuse projects are driven more by stewardship than economics. Filtration of starch, sugar and fats for use as animal feed has helped some processors offset treatment costs, although that revenue source may dry up under Food Safety Modernization Act regulations.

Limited water availability almost scuttled Algoma Orchards’ plans to expand into juice production when the Canadian packer was planning a new facility in Bowmanville, Ontario. Provincial authorities steered Algoma to Toronto-based Altech Technology Systems, which engineered a closed-loop recycling system that combines anaerobic MBR, two ultrafiltration units, reverse osmosis and chlorine dosage to treat and recover flume water and minimize fresh water needs by more than 3.6 million gallons annually. The system, in operation since December 2009, is the first of its kind in North America and possibly the world, according to the Bloom Centre for Sustainability.

“Food companies don’t like to have the people who maintain the outside equipment working on the inside equipment,” muses McCloskey. Often they opt to outsource maintenance and operations rather than handle it with in-house personnel. “The simpler we can make operations, the better. That’s what they’re looking for.”

Treatment systems must be tailored to the biological loads and requirements of a particular plant, engineers say, and state and local regulations are driving many of today’s upgrades. Phosphorous limits in Wisconsin, for example, are now 0.075mg per liter, down from 1-2mg/L, Probst points out. “It requires tertiary treatment to get to that level, and that doesn’t allow for any hiccups, and there are always hiccups,” he says. Given the prevalence of phosphorous in milk, the new regulations pose a considerable challenge for the state’s dairy processors.

Waste not

Perhaps the best strategy for managing wastewater or plant refuse is to limit it in the first place. Water efficiency programs reduce the volume of wastewater to be treated. Likewise, recycling and reuse efforts can minimize tipping fees paid to the local landfill.

Effective waste reduction programs require changes in people’s behavior, and elimination of waste hauling at Hormel Food Corp.’s Century Foods division, based in Sparta, Wis., was accomplished through “wall-to-wall engagement,” according to Tom Raymond, Hormel’s director of environmental sustainability. The corporate goal is a 10 percent cut in solid waste to landfill by 2020. The Sparta facility completely eliminated landfill hauls in October 2013 at four production facilities.

Century, a processor of dairy- and vegetable-based protein powders, began focusing on recycling and waste reduction in 2008. Until then, cardboard was the only recycled material, calculates Wade Nolte, vice president-operations. By 2012, 90 percent of scrap was being recycled, and a focus on “a lot of little things that really are difficult to recycle” pushed Century to zero waste, Nolte reports.

Multiple collection bins were placed in every department throughout the buildings, with as many as eight in lunch rooms and other employee welfare areas, to facilitate material segregation — paper, aluminum cans, plastic bags, food waste, etc. Much of the waste has commercial value, and the proceeds from recycled plastic were enough to offset capital outlays for bailing equipment and other costs.

“At a minimum, it was cost-neutral, and for us, we’ve been above neutral every year,” reports Nolte. “Any waste that goes into a landfill costs us 5 cents a lb.,” and expense avoidance further improves the ROI.

Employee engagement yields the greatest return. By focusing attention on reducing scrap, workers identified changes that reduce waste when lines start up, boosting production availability in the process.

Not everyone’s an environmentalist, and a backlash to sustainability initiatives always is a possibility. Nolte credits Hormel’s “continuous improvement mentality” for gaining cooperation and buy-in to waste reduction initiatives. “Nobody’s going to disagree with keeping waste out of a landscape, so it’s not a difficult sell,” he says.

Suppliers often are amenable to making packaging changes to support waste reduction programs. A Century ingredient supplier used 50-gal. barrels with metal rims until the company asked for all-cardboard barrels to make recycling easier. “That was cheaper for them, too,” Nolte observes.

International standards allow any company that diverts 90 percent of its waste stream from landfills to lay claim to zero waste status. Some groups are pushing for more rigorous standards, according to Cheri Chastain, sustainability director at Sierra Nevada Brewing Co., Chico, Calif. She sits on the board of the U.S. Zero Waste Business Council, along with representatives of Toyota, Disney Corp. and other firms.

Chastain’s firm, which should top 1 million barrels of production this year, sends 0.2 percent of gross waste to landfills. Reuse is the preferred application for the other 99.8 percent, followed by recycling and composting.

While the brewery emphasizes sustainable manufacturing practices, there’s a solid business reason for zero landfill use. In 2013, the company avoided $6.2 million in tipping fees, and recycled waste generated $980,000 in revenue, according to Chastain. Those figures represent 24 percent and 12 percent improvements respectively over the previous year.

Monthly tipping fees were steadily rising for Piazza Produce in Indianapolis and causing distress for facilities manager Scott Lutocka when he uncovered a consultant’s report written two years before he joined the firm. The audit identified corrugated cardboard as half the waste stream, and despite the purchase of a bailer, it remained at that level, accounting for more than 1,000 tons of landfill waste.

Over the next six years, sales volume increased 40 percent, yet hauling costs fell more than 70 percent (primarily for waste-to-energy incineration). Recycled cardboard and plastic now generate up to $50,000 in annual revenue. “It sounds clichéd, but there’s cash in your trash,” advises Lutocka.

“It took months to change habits and culture, but a little perk garners attention,” he continues. Utility knives were appreciated gifts that won staff buy-in to materials separation. Workers who manned the bailer and trash compacter were rewarded with monogrammed company jackets. “They were in tears,” Lutocka recalls. “Nobody ever gave them anything before.”

More than 95 percent of waste now is diverted, with food waste either composted or donated to food banks. Programs like Piazza’s resonate with customers, particularly supermarket chains advocating sustainability throughout the supply chain. “In time, solid waste is going to be regulated,” Lutocka believes. “Why not be seen as a leader and have a competitive edge?”

Wastewater treatment and solid waste disposal are costs of doing business that mainstream processors would prefer remain out of sight and out of mind. For those who recognize the potential value in their waste, opportunities to turn costs into benefits are increasing.

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