BioCycle Magazine

Compost Users Forum : Compost Research On Wisconsin Organic Farm

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 Cocomposting at Pearl Harbor


“One unique local characteristic (and treatment difficulty) we encountered in our composting program,” says Stan Konno, PWC environmental department director head, “is the high level of diesel range total petroleum hydrocarbon (TPH) content in the sludge from the WWTF at Fort Kamehameha.” Oil from past leaks in pipelines and tanks — which go back to 1941 — penetrates the wastewater collection piping system and causes the high hydrocarbon content. “We were asked to develop a process to degrade the TPH contaminants as well as convert the biosolids into compost,” explains Dennis Chang, the solid waste branch manager and site operator.

Contamination levels in the biosolids can be as high as 200,000 ppm (about 20 percent contamination of the biosolids). Resultant analyses confirmed that the finished compost exhibited no detectable toxicity, leading the Hawaii Department of Health to allow unrestricted use of the end product on DOD property. To illustrate that the compost produced would have no ill effects on either plants or the environment, PWC — in cooperation with the Navy Facility Engineering Service Center (NFESC) at Port Hueneme, California — conducted a field study (“Assessing the Fate and Impact of Residual Hydrocarbon-Like Components in Composted Biosolids Applied to Garden Soil”). A test plot (20 by 20 by 3 feet) was divided into four sections. Composts of different ages (20 days, six weeks and 11 weeks of curing) were applied to three sections; the fourth section served as the control. Carrots and onions were planted for evaluation. Studies of plant viability and yield showed that there was no significant difference between plants in the test plots versus the control. Hydrocarbons were not detected in any of the pore water samples using two different EPA methods.


Tipping fees for biosolids delivered to the PWC compost site are comparable to charges at the local landfill, notes Konno. “For city and county deliveries, we charge $72/wet ton, with a ‘surcharge’ of $10/ton for the compost since it gets applied on public projects,” he points out. For the military, there’s currently no extra charge beyond the $72.

Looking ahead to expanding organics recovery on Oahu and other Hawaiian islands, the PWC staff points out that “we’re using almost all the biosolids being generated on the Department of Defense side on Oahu. It’s up to the county to send us additional quantities of biosolids.” The Navy and Army are each sending nine wet tons/day (five days/week) of biosolids to the composting site. The city/county of Honolulu is delivering twice a week, providing a total of 40 wet tons a week. On February 1, 2000, PWC Pearl Harbor was issued a five-year operating permit from the Hawaii Department of Health. The permit provides that compost produced from the military’s wastewater biosolids is not restricted in its use and application provided it remains on DOD property. It also notes that capacity may be increased up to 200 wet tons/week of biosolids from the city and county of Honolulu.

The Navy’s biosolids facility was named Project of the Year by the American Public Works Association Hawaii Chapter for the less than $2 million category. “We’re very proud of our facility and the personnel who manage it,” said Konno. “This award serves to recognize their accomplishments and confirm the Navy’s commitment to protect Hawaii’s fragile environment.

Compost Research On Wisconsin Organic Farm

At Harmony Valley Farms in Viroqua, Wisconsin, owners Richard de Wilde and Linda Halley apply composted manure on their entire 70 acres of vegetables and fruits. But that practice has not always been followed during their 16 years at Harmony Valley.

In 1991, they sold their livestock and stopped using composted manure. Soon de Wilde and Halley noticed an increase in foliar diseases. To determine what was causing the problem, they began working with the Center for Integrated Agricultural Systems (CIAS) at the University of Wisconsin-Madison to conduct joint on-farm research in 1997 and 1998. The first objective involved studying disease suppressive properties of soil amended with dairy manure compost and exploring any influence compost amendments had on crop health and productivity at Harmony Valley. The second goal was to collect soil microbial data on the farm where links between microbial indicators and yield could be investigated. Researchers at the CIAS hoped to use soil from the trials as starting material for developing DNA-based methods for assessing soil microbial communities.

Scientists involved in the study included Robert Goodman, Gary Vallad and Beth Kazmar of the University of Wisconsin’s Plant Pathology Department. They monitored crop disease responses to field treatment. The plant pathologists are continuing their investigations with soils collected from the trials. Research by Jeff Dillen at the University’s Institute for Environmental Studies on samples from another farm showed that a DNA-based method could detect microbial community shifts in response to long-term, 30-year differences in crop management. An extensive collection of microbial DNA samples from the trials at Harmony Valley has been archived for future analysis.

Ten Percent Increase In Yields

Four treatments were studied in the field trials: an untreated control, composted goat manure, composted dairy cow manure, and a commercially available feathermeal product mixed with soybean meal which was included as a NPK fertility control. To help isolate compost’s nonnutrient effects, researchers varied compost application rates between ten and 15 tons/ acre to match compost nutrient levels and those of the NPK control.

The same field was used in both seasons, allowing observations on cumulative effects of compost applications in the second year. Each year, two crops were planted in adjacent strips.

To the researchers’ surprise, using dairy manure compost increased crop yields by an average of ten percent even in the presence of microbial disease. According to Research Brief #45, published by the CIAS, some diseases were less severe in plots treated with the compost, but other diseases, particularly those involving the fungus Rhizoctonia solani, were more severe. Both dairy and goat manure composts appeared to limit the disease Cercospora. However, use of compost increased several diseases caused by the fungus Rhizoctonia solani. But the increase in disease on crops with compost amendments was often accompanied by an increase in yield. Another striking finding was how crops responded to compost in dramatically different ways. The beet crop responded strongly to goat manure compost and dairy manure compost. But the carrot crop planted six feet away responded most strongly to the goat manure compost.

The soil microbiology research also found that the ratio of total fungal to total bacterial biomass was a strong predictor of yield. This measure was capable of distinguishing the soils collected from amended and unamended plots, revealing that the dairy compost had indeed changed the soil microbial community. Composts continue to be a useful part of soil management for Harmony Valley, but de Wilde uses compost in conjunction with other techniques such as extended rotations of susceptible crops and rotation to grasses where feasible in order to manage levels of Rhizoctonia.

Compost Sources

Only dairy compost is now used on Harmony Valley Farm, 80 percent of which is made by de Wilde from bedded manure purchased from neighboring farms. Manure is mixed with legumes, corn stalks, soybeans or hay to achieve a C:N ratio of 20 to 1. His five windrows are turned at least once a week for six to eight weeks. The turner is pulled by a hydrostatic drive tractor; each windrow is 500 feet long and contains 60 tons of feedstocks. Compost is spread in fall over Harmony Valley’s 70 acres at three to five tons per acre, supplying all the nitrogen, phosphorous and potash needed. “The material is dry and crumbly, not wet like raw manure,” says de Wilde. “All my labor and fuel costs are cut in half because I’m spreading only half as much compost (as raw manure), and the load is lighter because it is dryer and spreads faster.”

Harmony Valley purchases the remaining 20 percent of the compost it uses from Paul Rosenow — a dairy farmer in Cochrane, Wisconsin — who beds his free stalls with dry sawdust obtained from local mills, kiln drying and planing operations. Approximately ten percent of the mixture is sawdust bedding and the remaining 90 percent is liquid manure. “The stalls are flushed daily into an alleyway and a reception pit,” says Rosenow. “The reception pit agitates the mixture of water, sawdust and manure with pumps. The mixture is then pumped to an inclined screen separator. The liquid portion falls through the screen and by gravity goes to one of the lagoons. The solid portion slides off the screen onto a watertight concrete stacking pad where it is accumulated and taken to the composting site.”

At the composting site, windrows are formed on two acres of asphalt pad and turned. After the active phase is completed, the compost is put into a larger windrow, for about six months to become market ready. At that time, Rosenow sells the compost at a wholesale price of about $12/cubic yard.

Evaluating Finished Compost Impact On Crops

While the compost purchased from Rosenow constitutes only about 20 percent of his compost source, de Wilde really likes Rosenow’s dairy compost mixture. “It’s a wood derived mixture meaning it is fungus dominated versus bacteria dominated like the corn stalk, hay, and soybean mixture. It has a nice woodsy smell. Our straw based compost is bacteria dominated. The fungus based compost may be better for strawberries, raspberries and our other crops.”

The problem of too much water presents de Wilde’s greatest challenge with composting. In July and early August, the upper Midwest suffered from constant rain that ruined crops for many farmers and threatened compost piles as well. He is considering purchasing covers for the windrows.

Keeping the compost located at a high, dry area helps drainage so windrows are situated on a hill with lengthy grass to absorb and filter any runoff. Odor is not a problem, according to de Wilde, as long as the 20 to 1 C:N ratio is maintained. “Anything less than 20 to 1 would create odor problems,” he says.

As a result of their willingness to experiment, Richard de Wilde and Linda Halley are contributing to advances in modern science in disease suppression and microbial communities. And they are in turn, fully committed to composting. “Participating in the research project definitely reaffirmed our commitment to compost,” says de Wilde. “But, I’m also glad to contribute to the body of scientific knowledge about farming methods.”

Is compost an economical option for Harmony Valley? “Yes,” says deWilde, “after seeing the results of our experiments, we definitely plan to continue making and using compost. We expect to eventually be able to reduce our application rates as the compost accumulates in the soil, improving soil structure and tilth. These are important long-term benefits with our sandy loam.”

DeWilde figures that if he can average a ten percent yield increase for all crops using compost, he will increase average gross profit sales by $800/acre. This would make it well worth the costs of making the compost including equipment depreciation, even at $25/ton or $300 to $400/acre. “Economic benefits are even greater when long-term effects are accounted for,” says deWilde.

Research data on the benefits of composted manure use at Harmony Valley Farms have been compiled by staff at the Center for Integrated Agricultural Systems (CIAS). The Center brings together university faculty, farmers, policy makers and others to study relationships between farming practices, farm profitability, the environment and rural viability. CIAS is based at the University of Wisconsin’s College of Agricultural and Life Sciences in Madison, WI. (608) 262-5200.

By Jo Anne Killeen

Georgia Takes Many Routes to Recycle Food Residuals

The many approaches being taken to utilize food residuals generated by processors, cafeterias and households are evident throughout Georgia. Near Atlanta, Arden’s Garden Juice Company is cooperating with a nearby farm and staff at the University of Georgia to divert pressed juice pulp from the landfill. Once a week, East Lake Farm manager Ryan Cohen drives a pickup truck to the juice processing plant, where employees put the pulp into the back of his truck instead of the dumpster. Feedstock is easy to handle because it has been dewatered and ground into small particles in the juice pressing process. Then the juice residues are mixed with residential yard trimmings picked up by Cohen at curbside and composted; in as little as two months, the compost is ready to fertilize garden and farm soils.

Arden’s Garden is a fresh fruit and vegetable (smoothie) juice company that caters to the health conscious community. According to owner Leslie Zinn, besides reducing disposal costs, “recycling the juice waste and returning it to the farmer creates excellent public relations with our consumers.”

Total time spent on picking up the feedstock, mixing, filling bins, and monitoring older piles averages two hours per week. Cohen explains: “This feedstock is perfect for composting. We are lucky that our farm is located around so many potential sources of free organic feedstock. East Lake Farm is a great example of how urban farms can play a major part in the solution to divert organics from the landfill.” The University of Georgia and the Pollution Prevention Assistance Division of the Georgia Department of Natural Resources are providing technical assistance to create an on-farm demonstration facility to educate the public on industrial by-product recovery through composting. Self-guided tours through the farm will feature educational signs on the basics, benefits and opportunities for composting.

East Lake Farm (Gaia Gardens), located three miles outside Atlanta, is part of the larger East Lake Commons Community, where townhouses have been built alongside the five-acre organic farm to create a neighborhood green space in this environmentally conscious urban neighborhood.


Results of a three-month aerated container pilot study are being used to expand the University of Georgia’s food residuals composting program into a full-scale operation. Collected materials will be incorporated into yard trimmings windrows at the university’s Bioconversion Research and Education Facility. At 19,000 meals a day, the biggest challenge is keeping the feedstock free of plastic contaminants and inerts. Specifically, straws and condiment packages are the impediments. We are analyzing the cost difference between using biodegradable food service items and having the material source separated at the cafeteria level. The feedstock is great for handling and transport because the pulping process it undergoes not only reduces the high moisture content (typically 90 percent), but reduces and homogenizes particle size. The food residuals provide an excellent source of nitrogen (five percent) to the carbon-rich yard trimmings for land application on university grounds. The pilot study found the university will save $12,000/year in tipping fees once it begins recycling its food residuals full-scale.

At another project in the Athens/Clark County region, food residuals from commercial generators are being collected by a nonprofit organization called Organic Diversion Recyclers, which was founded by Mark McConnell. Materials are collected from 35 area coffee shops, restaurant chains and supermarkets, averaging 1,000 lbs/day. Food residuals are mixed with woody materials and papermill sludge using static piles on a 22-acre site. Finished product is sold through Creative Earth Company, also founded by McConnell. The University of Georgia is providing technical assistance.

Located in central Georgia, the Jasper County school system is completing construction on a new elementary school that will include a food residuals composting program. Students will be involved in monitoring the compost through the county 4H/Youth Development Program and various science classes with assistance from the University of Georgia’s Cooperative Extension Service. Washington Park Elementary will use a three bin system that will also include the school’s yard trimmings and grass clippings. Educational signs will be posted around the site to further explain the importance, aspects and uses for compost. There has been interest in expanding this program to all the schools in the county system.

By Britt Faucette

Composting Food Service Scraps at Resort

SMUGGLERS’ Notch Resort, a ski and summer resort in Jeffersonville, Vermont, is running an on-site composting program to collect preconsumer food scraps from its food service and restaurant facilities. Resort personnel began planning in late 1998 and management approved the project in June, 1999. According to Chris Bolen, environmental permits and compliance coordinator for Smugglers’, four seven-foot-square by five-foot-high composting bins were built in August with pressure-treated wooden sides and concrete floors. Composting began in time to capture food residuals from the fall foliage tourist season in September and October.

On-site composting means significant cost savings for Smugglers’ as well as waste diversion from landfills. “We have a lot of flower gardens to fertilize and protect in winter,” says Bolen. The resort’s landscape gardeners provide the necessary labor and use finished compost in the flower beds. “Making our own compost saves money in two ways,” says Bolen. “By keeping the food waste on-site, we avoid paying the $116/ton cost for landfilling it, and every yard of compost generated means one less yard that we need to purchase elsewhere.”


Casella Waste Management, Inc. of Vermont, the resort’s trash and recycling hauler, provides Smugglers’ with free 64-gallon, lidded plastic containers for organics collection. The containers, labeled “meat compost only” and “vegetable compost only,” are placed at the resort’s Meeting House, which includes a restaurant and food service complex managed by Boston Concessions Group. “The food service vendor is fine with it,” says Bowen. “We realize, though, that they have limited space and are not going to capture 100 percent of the food waste.” Food residuals containers are also placed at the Hearth and Candle, a restaurant in a separate building leased by the resort to an independent restaurateur.

Bolen is in charge of training Boston Concessions Group’s kitchen staff on how to separate preconsumer food residuals. “I gave the staff some laminated lists provided by Casella, which tell what can and cannot be composted,” he says.

Once the containers are filled, kitchen staff wheel them outside. Resort service personnel collect them along with recyclables and regular trash. The food scraps and plant residues from the gardens are ground using an eight-horsepower chipper and composted with horse manure from a neighboring farm. Meat scraps and any excess vegetable material are hauled to the Intervale Compost facility in Burlington by Casella on an on-call basis (see “From Ice Cream To Nuts In Food Residuals Composting,” October, 1998). Bolen says that Smugglers’ cannot compost meat in its bins because of the likelihood that it would attract wild animals and create offensive odors.

According to Bolen, cold weather makes on-site composting impractical in the winter, and labor is less available. From November through April, all of Smugglers’ compostable material is shipped to Intervale Compost. Casella charges approximately $65/ton for composting versus $116/ton for landfilling.

The 1999-2000 ski season was the first full one of operation for the Smugglers’ composting program, although food residuals were collected from Meeting House kitchens only. “In order for our programs to be successful and economically viable over the long term, the activities of several groups must be coordinated,” says Bolen. “Our food service vendor, Boston Concessions Group, our solid waste service personnel, the flower ladies (landscapers) and Casella must all work together.” Bolen limited collection to one venue “until all the players know the drill and the program is running smoothly.” Smugglers’ hopes to expand the program to the Morse Highlands and Base Lodges during the upcoming winter season.

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