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Company 'Excel's at Achieving Waste Reduction Goal

Printed with permission from BioCycle.

Excel Corporation
Beardstown, Illinois

The Story: On-Site Composting of Meat Processing Residuals Helps to Reach Goals

IN 1997, Cargill, Inc. set a corporate wide goal of a 30 percent reduction in solid waste by 2000, using 1997 as a baseline. When the company achieved that goal, it instituted a subsequent goal of another 30 percent waste reduction by 2005, using 2000 as a baseline.

Excel Corporation, a Cargill subsidiary that processes pork, beef and related meat products at several locations around North America, took on that challenge. At its Beardstown, Illinois plant, getting the first 30 percent had been relatively easy, essentially going after the low-hanging fruit like certain recyclable materials and improved wastewater treatment operations to reduce eventual waste stream volumes. The second goal would be much tougher to achieve, going beyond the "reduce and contain" initiatives of Stage 1 (the 30 percent goal) to the more proactive efforts of Stage 2 that involve the conversion and elimination of wastes. Stage 2 serves the dual goals of saving containment space (e.g. landfills) for critical materials and also creates opportunities to actually improve environmental conditions.

About 95 percent of the waste streams at the Beardstown plant are organic materials that are easily composted. This includes 2,500 to 3,000 tons/year of cardboard and processing plant waste (wastewater stream screenings, paunch material, some livestock bedding and a small amount of manure) that were being landfilled in a 40-mile radius of the plant. Additionally, about 20,000 tons/year of biosolids (wet basis) are being spread on farmland. Targeting these waste streams would move the facility well beyond the mandate from Cargill. After evaluating a number of alternatives, composting was chosen as the best strategy for Stage 2 waste management.

Partners Help to Test the Concept

Adequate acreage and the availability of additional carbon sources at the processing plant led to the decision to compost on-site. Because of a lack of experience in the composting arena, the first step was to find the right partners.

The first partner selected was Midwest BioSystems, a composting consultant, biological soils fertility group and equipment supplier in Tampico, Illinois. The company's founder, Edwin Blosser, originated his business in soil fertility. He needed a high-grade biological material and very high-grade compost was the only thing that met that need. Blosser developed a very intense controlled composting process to get the high-grade product desired. Excel staff weren't nearly as interested in the final product as in the process. People within Cargill supported the Beardstown effort on composting, but were very concerned about the possibility of taking one pile of waste and turning it into another pile of waste and making a big stink in the middle. Therefore the primary focus was on "in-process" control rather than the product.

It soon became apparent that a very high level of in-process control also would yield a very good product. Excel then partnered with a neighbor of the Beardstown plant, Illinois Forest Products (IFP). IFP is an upscale nursery company that agreed to cooperate with Excel on product marketing.

The final partnership was with the Illinois Environmental Protection Agency (IEPA). Excel began discussions and negotiations with them early on and continues to stay in contact. The Illinois EPA provides an opportunity to do testing before jumping into full-scale production, which proved to be extremely helpful.

The Beardstown test operation involved setting up a 200 cubic yard windrow built out of all the waste streams that were potentially compost feedstocks. The trial was initiated in May 1999. Following construction of the windrow, an Aeromaster turner was leased and the row was taken to full completion in about ten weeks. There were no vector attractions or odors and the process yielded a very good product. This provided the confidence at both the local and corporate levels to allow movement to a full-scale project.

Facility Design and Operation

The permitting and siting approval process began in the summer of 1999 with actual site preparation beginning that fall. The facility began operating on a full-scale basis in July 2000.

The composting site is on 17 acres adjacent to the wastewater treatment operations. The site includes a five-acre pad with the capacity to handle up to 15,000 tons/year of material as well as three abandoned anaerobic lagoon basins that create the future ability to expand to a 12-acre pad. The site has a one percent slope in the direction of the windrows and a base made of over 12- inches of compacted clay that exceed the 10-5 cm/sec infiltration requirements. A compacted crushed limestone topping of about four-inches creates an all weather surface. Rain event runoff is managed by a collection system that discharges into a part of the plant's wastewater treatment system. The site also includes a loading, storage and maintenance area. Separate storage and cleaning/sanitation buildings are under construction.

The three abandoned anaerobic lagoon basins each contained about three to four feet of residual biosolids. These have been the primary nitrogen source in the initial stages. As noted above, as these lagoons are emptied, the pad can be expanded. A belt press is being installed to thicken the waste activated sludge (WAS) currently being generated so it can be included in the composting mix. This will replace the residual anaerobic sludge as the primary nitrogen material within the next few months.

Cardboard is the primary carbon source in the initial mix. About 1,000 tons/year of waste cardboard are generated. This material is shredded in the plant into ten to 20 inch-size pieces, then loaded on a truck and brought to the composting area where it is ground in a Haybuster 1100E tub grinder through a three-inch screen. Because the plant generates feedstocks that are stronger in nitrogen than carbon, corn stalks and wheat straw also are added. Excel has 400 acres of farmland at its facility, and the stalks and straw are baled at harvest and put through the tub grinder as needed.

The biosolids make up about 80 percent of the nitrogen source in the mix. Biosolids in the anaerobic lagoons are removed from the basins via end loader and truck and transported to bunkers in the loading/mixing area. In the near future, the belt-thickened biosolids also will be trucked to bunkers in the loading/mixing area. Noncardboard materials (wastewater stream screenings, paunch material, some livestock bedding and a small amount of manure) generated in the processing plant are collected daily and also trucked to the loading/mixing area and put in bunkers so that mixing can be accomplished in a more expeditious fashion.

Feedstocks are weighed and combined in a Knight mixer. A certain amount of clay is added as a buffer. About 800 cubic yards/ week of materials are processed and put in windrows built about ten to 11-feet wide, about five-feet high and 200-feet long. The average life of a windrow is eight to ten weeks. During that period, the windrows are turned about 20 times. Determining when to turn is based on measured CO2 and temperatures.

Water can be added to the windrows via a tank pulled behind the turner. This unit also is used to add inoculants that accelerate the composting process and get the desired microbial profile. Windrows are sometimes covered between turnings to help in moisture management.

Marketing the Product

After eight to ten weeks of composting and curing, a pathogen check is run on the compost as well as a maturity test using the Solvita kit. If the desired quality has been achieved, the finished material is moved across the road to Illinois Forest Products for further preparation for market. The compost is screened to about three-eighth inch using CEC equipment. Once Illinois Forest Products begins bagging the material, the screen size likely will be reduced to one-quarter inch.

Several thousand tons of compost have been produced since the system started up. Several hundred tons were utilized around the Excel facility as part of a green belt appearance enhancement project. Illinois Forest Products has used some in-house for its own nursery, tree farm and landscaping operations. The remainder has been marketed for landscape and nursery uses in the 150 mile radius around the Beardstown area.

A number of marketing seminars have been held with the participation of Excel, Illinois Forest Products and Midwest BioSystems personnel. The purpose of these seminars is to help customers understand the value of compost and how to differentiate compost quality and value for their own uses. These seminars have been well received and feedback on their value to the customer (and ultimate purchase of material) has been positive.

Revising Strategies to Achieve Success

Since the Beardstown composting facility began operations about a year ago, certain challenges have arisen along with the successes. The first challenge was related to nitrogen impact. Biosolids would be naturally dewatered to about 25 percent solids and then removed from the anaerobic lagoons to the loading/mixing area. The removal process occurred weekly and in the first stages the same general areas of the basins would be revisited each week. However, after several months of removal (and a greater area devoid of sludge), several weeks could pass before a specific area was revisited for further removal. It was learned that when several weeks passed, some of the remaining biosolids at the sludge removal face actually had started to compost in situ. The net effect was an expiration of nitrogen "punch" in the mix sooner than expected.

As a result, the nitrogen management plan has been revised. The first step is to minimize the surface face when stored biosolids are removed. While some of this can be managed in the removal process, as each basin nears completion a certain time exposure is unavoidable. Expectations are that it will take up to two years to complete removal of the residual materials so this problem must continue to be managed. A more certain solution involves the replacement of the residual material as the primary source with the WAS and anaerobic blow-down sludge from the belt filter press. This material is "fresh" every day and eliminates the in situ composting problem. This change should be reflected in the mix by late summer or early fall of this year.

A second major challenge was related to winter-time composting. Initial testing had spanned winter conditions, but those conditions were not as cold as what was experienced this past winter. In fact, several hundred tons of product this spring did not meet final specifications in either pathogen limits, Solvita requirements, or the general compost marketing specifications. Some of this material was reprocessed and some has been used on-site around the wastewater treatment area to enhance the green belt there.

Operational changes will be implemented for future winter conditions. This will include the reduction of any frozen feedstocks, grinding carbon sources more finely, reducing moisture levels and building the windrows as large as possible. Turning also will be more restricted under winter conditions.

Implementation of the composting operation at the Excel facility in Beardstown, Illinois has been a sustainable win-win situation. The plant is saving money and is reducing its environmental liability. Disposal costs of up to $60/ton have been reduced. Total solid waste in the fiscal 2000-2001 year at Beardstown was reduced by about 50 percent, which already meets the Cargill goal. With increased operating time in the coming years as well as the ability to compost additional wastes, this reduction is certain to improve. It is also a win for neighbors of the Beardstown facility, including their marketing associate, Illinois Forest Products. Finally, it's a win for the regulators in the state of Illinois as well as the citizens of that state and region.

Lessons Learned:
  • Taking the first step is often the easiest. What seemed to be a difficult initial goal to reach for Excel, a 30 percent reduction in solid waste between 1997 and 2000, was actually relatively easy to achieve. The company was able to reduce waste stream volumes by finding recyclable materials and improving wastewater treatment operations.

  • Find where you can make the biggest difference at your facility. Excel began looking at its waste reduction goal by looking at where it could produce the biggest changes. This led the company to examine its waste streams, which turned out to be 95 percent organic materials that are easily recycled.

  • Partners bring experience and encouragement. When it began to tackle its second goal of reducing waste by 60 percent, Excel chose to compost its organic residuals. It had no experience in composting, so it sought the help of Midwest BioSystems, Illinois Forest Products and the Illinois Environmental Protection Agency. These partners helped Excel test its concept for waste reduction and refine the composting process to achieve high levels of success.

  • Understand your facility. Excel took a great amount of time to study and understand the design and operation of its facility. This knowledge is crucial when trying to make improvements to processes, or finding ways to cut wastes. It is also critical to understand your facility should any problems arise -- you will then be able to respond quickly.

  • Turn waste into useful products. Through its composting efforts, Excel has actually created a product that is valuable to one of its partners, Illinois Forest Products (IFP). The compost is used in IFP's in-house nursery, tree farm and landscaping operations, and was used by Excel as part of a green belt appearance enhancement program. What wasn't used by these companies is then put out into the larger market and used by landscapers and nurseries in a 150 mile radius from Beardstown.

  • Be flexible with your plans. Excel faced many challenges that arose after it had begun working toward its waste reduction goals. It remained flexible in its approach and was able to address these problems as they arose, and still reach its goals.

Contact Information
Excel Corporation
2901 N Mead St.
Wichita, KS. 67219

Phone: (316) 832-7500

Printed with permission from BioCycle.