October 22, 2004 | General

Leaf Composting Project Grows Up With Multiple Feedstocks

The 29,000 tons processed annually at Burlington, Vermont’s Intervale include food residuals, manures, ice cream waste, hay, wood shavings as well as yard trimmings.

Molly Farrell
BioCycle October 2004 Vol. 45, No. 10, p. 27

What is now Vermont’s largest composting operation started out as a volunteer effort to compost the leaves of Burlington, Vermont’s residents. Today, Intervale Compost Products (ICP) processes more than 29,000 tons of organic materials annually on a 15-acre site. That total includes more than 2,500 tons of food residuals; 2,500 tons of cow manure; 3,500 tons of horse manure; 2,000 tons of chicken manure; 4,500 tons of leaves and yard trimmings; 4,000 tons of ice cream waste; and nearly 10,000 tons of bedded straw, hay, sawdust, and wood shavings.
The project has had its share of challenges along the way, including the gradual loss of one of its biggest liquid feedstock providers, Ben & Jerry’s Homemade, Inc., and serious drainage problems with its compost pad.
The community leaf composting project was started by Will Raap, founder of Gardener’s Supply Company, a mail order company located in Burlington’s Intervale, a 700-acre tract of former farms and fields. Raap volunteered to have his employees compost leaves on one-quarter acre of land. “The original concept was to compost the leaves through a rotational system by pushing them around with a 20-hp farm tractor,” explains Adam Sherman, Manager of ICP. “With only one-quarter acre, it wasn’t at a size or economy of scale to be self-sufficient and viable.”
The nonprofit Intervale Foundation, also founded by Raap, set up ICP in the Intervale in 1987. The foundation was starting a program to draw farmers back to the Intervale by offering training, low-cost leases on farmland, and low-cost equipment rentals. “We started the compost project both to restore the Intervale’s depleted farmland and to create a model closed-loop recycling business of organic residuals being composted and compost being used to grow more food,” says Raap. The compost facility would be able to produce compost for Intervale farmland, and generate revenues to help support the farm as well as other projects.
In 1993, ICP applied for a permit from the state of Vermont’s Agency of Natural Resources to compost food residuals in partnership with the Chittenden Solid Waste District (CSWD), the solid waste authority for most of the towns in Chittenden County.
ICP’s first “closed loop” customer was Fletcher Allen Health Care (FAHC), Vermont’s largest hospital complex. Food waste from FAHC was composted at Intervale Compost, and in turn, FAHC agreed to purchase produce from an Intervale farmer who used the compost to grow more food. In 1993, ICP began receiving food residuals from FAHC and the Perry Restaurant Group, as well as liquid ice cream waste from Ben & Jerry’s Homemade.
“The model with FAHC really worked,” notes Raap. “The hospital wanted to reduce its waste. We said we’ll take your food waste and in return, you agree to buy ‘X’ amount of food from our farm.”

Private Haulers Recruited

In 1994, ICP started recruiting private haulers to haul food residuals to its compost site, offering a $40 per ton tip fee compared to the $91 per ton fee charged by the local transfer station. To encourage greater diversion rates, in 1996 ICP dropped its food waste tip fee even further, to $25 per ton.
The first private hauler to bring food residuals to ICP was a local moving company, Booska Movers. It soon formed a sister company, Food Waste Management Inc. One of its employees outfitted a 1981 Ford F700 truck with a hydraulic lift to collect food residuals in 64-gallon toters. The hydraulic lift on the single-axle, open top, dump body truck hooks onto two 64-gallon toters at a time, lifts them above the dump truck bed and dumps their contents into the truck bed. The toters are then hydraulically lowered back to the street.
Food Waste Management was purchased by Casella Waste Management in 1998. Casella continues to collect more than 95 percent of the commercial food residuals brought to ICP, under the (d/b/a) All-Cycle Waste Management.
In 1995, ICP received the state’s first full compost permit and began commercially selling finished compost. By 1999, ICP was composting more than 1.2 million gallons of liquid ice cream waste and more than 1,500 tons of commercial food waste.
In the beginning, much of the compost produced by ICP was used on Intervale farmland. Thirteen organic farms are currently operating in the Intervale on restored land. Together, they produce 500,000 pounds of fresh produce, of which 50,000 pounds are donated to local social service agencies. This year, ICP expects to sell more than 15,000 cubic yards and 30,000 bags of product. ICP is self-funded, but still receives technical and business assistance from the Chittenden County Solid Waste District.

Ben & Jerry’s

Ben & Jerry’s, which opened its first ice cream shop in Burlington in 1978 and is now owned by Unilever, has gradually reduced the amount of ice cream waste it brings to ICP from its Vermont production facilities. This year, Sherman expects to receive only 4,000 tons of ice cream waste (ice cream weighs 9.2 pounds per gallon).
“Ben and Jerry’s has been one of Intervale Compost’s mainstays,” notes Sherman. “They certainly helped us achieve notoriety in the compost industry for handling their liquid ice cream waste. We’ve been weaned back now because Ben & Jerry’s ultimate goal is to not make any waste. Our relationship with Ben & Jerry’s started as a win-win because they got good will for turning their waste products into compost and we got what we needed to make compost,” says Sherman, adding, “it’s still a great relationship.”
Another collaborative project between the ice cream giant and the compost project is also waning. Sherman approached Ben & Jerry’s in January 2001 about creating a product together. “I was looking for ways to add value and revenue to our compost sales, so we’d be less reliant on bulk sales,” he explains. Together, they came up with selling pints of Terra Fuela. Instead of ice cream, each pint contains dwarf sunflower seeds and a plastic bag filled with Intervale Compost Products’s organic potting soil. Consumers empty the soil into the pint, plant the seeds, and watch sunflowers grow in the container.
Ben & Jerry’s designed the packaging for the product and debuted Terra Fuela at its annual Ben & Jerry’s One World One Heart music festival in June 2001. Intervale Compost sold the first 10,000 pints in two months. Ben & Jerry’s sells the empty pints at cost to Intervale Compost. Intervale Compost assembles the units and sells them through its own channels of distribution, including Gardener’s Supply Company.
“Terra Fuela was a great example of how we took the relationship to the next level,” notes Sherman. “We brought back Ben and Jerry’s own ice cream waste in a value-added form under their own brand. To apply Ben & Jerry’s brand to what is considered a waste product was a very strong gesture. It showed their commitment to what we are doing.”
Unfortunately, sales of Terra Fuela have fallen. “The initial novelty of Terra Fuela has worn off and now it’s on the backside of demand,” observes Sherman.

Pad Problems

For the last ten years, ICP has been composting on a farm field without doing prep work or site evaluation. “We didn’t want to do anything to affect the future farmability of the land,” says Sherman. That wouldn’t be a problem if the compost pad had the necessary slope, but ICP is located on a flood plain. “The field has limited drainage, so operationally we’re in a predicament. If it rains, that creates really muddy conditions.” Liquid drained off the first few years, points out Sherman, but slowly the native soil got built up with compost. Now the soil is highly organic instead of sandy and well-drained. “The rain doesn’t drain off or run off. This is terrific for future use of the fields as farmland. If we decided to relocate, the farmers would be foaming at the mouth. But it doesn’t work for composting.”
ICP considered pulling out of its current location and finding commercial land outside of Burlington. “We were told by state regulators that we had to buy commercial-industrial zoned land because they considered Intervale Compost a commercial and not an agricultural operation,” says Sherman. “We realized that we couldn’t afford to purchase commercially-zoned land. In Chittenden County, agricultural land sells for $1,500 an acre, and commercial-industrial land for $15,000 an acre. We would need one-half acre for offices, production and storage facilities, and 10 to 15 acres for a compost pad.”
ICP is evaluating different designs and materials to construct a compost windrow pad on 5 to 15 acres, and is going through the permit process. “Regulations, depending on how they are interpreted, may or may not allow us to make the necessary site improvements,” explains Sherman. “We hope to have a clearer understanding soon.”
Another challenge is plastic contamination, including the use of biofilm bags made from PLA and other non-PE materials.

Running The Composting Operation

ICP currently receives food residuals from three commercial haulers and more than 100 businesses. Sixty-five percent of the materials arrive in 64- and 68-gallon toters from supermarkets, restaurants and institution cafeterias. The remaining 35 percent arrive in roll-off or liquid tankers from food manufacturers. “The 64-gallon toter system works well for small food waste generators like restaurants,” notes Sherman.
Five-gallon pails are often used to collect food residuals indoors. The food residuals are transferred daily from the indoor pails to outdoor toters lined with bioplastic liners. The toters are lifted two at a time and their contents dumped into the open top truck bed. The single axle truck has a 25,550-pound gross weight capacity.
Food residuals are delivered to ICP two times a day, five days a week, in loads of approximately five tons per trip. ICP charges $25 per ton for commercial food residuals, compared to $93.75/ton at the local transfer station. Upon delivery, the materials are immediately blended with bulking agent (leaves, yard trimmings, bedded straw, hay, sawdust, and wood shavings) and active compost. “We do the blending right away for vector deterrence and odor suppression,” explains Sherman.
After the feedstocks are received, inspected, and blended, they are built into windrows in the field with a bucket loader. Windrows for liquid wastes are built on a 50-foot by 250-foot concrete pad with absorbent horse manure and leaves and shaped into troughs with a bucket loader. Liquid food wastes, including Ben & Jerry’s ice cream waste, are poured into the windrows as a source of liquid and nitrogen. Any runoff is captured in a 5,000 gallon, in-ground holding tank. The tank water is then recirculated onto the absorbent piles.
Currently, the windrows are being mechanically aerated with a Scarab windrow turner, but the facility is considering replacing the turner with an excavator. Materials are actively composted for nine months and then cured for two to three months. The composted and cured material is then screened to 3/8 inch.

Sales And Future Plans

Eighty percent of the finished compost is sold in bulk. The remaining 20 percent is sold in value-added form, including potting soil, germinating mix, custom blends, bulk bags and 20-quart bags. A line of new colorful bags was unveiled in 2003. The facility also brews compost tea.
This fall, All Cycle Waste, Inc. will begin bringing food residuals and corrugated cardboard from larger supermarkets to ICP using compactors, roll-off boxes and roll-off trucks. A grant from the Vermont Agency of Natural Resources Compost Center will fund a pilot project to collect the food residuals and wet and waxed corrugated cardboard from three grocery stores. Until now, All Cycle has been unable to collect the cardboard from supermarkets because it did not fit into the 64- and 68-gallon food waste toters.
All Cycle will use a standard compactor trash collection truck to collect sealed roll-off containers from the grocery stores. The roll-off truck will hook onto the box, hoist the box onto the bed of the roll-off truck, drive to Intervale Compost, weigh in, dump the contents of the box, and be weighed again. Of the $14,300 in grant funds, $5,000 will be used to build a rinsing facility at ICP to rinse off the roll-off boxes after their contents are dumped, to reduce odors.
All Cycle will continue to collect toters five days a week from smaller generators of food residuals using the hydraulic dump body truck. In February 2004, Sherman gave a presentation at a food residuals composting symposium at Bowdoin College in Maine, and was surprised to find that other facilities were jealous that ICP had a “milk run” toter system. “These facilities were able to service large generators like food chains, but couldn’t collect from smaller but worthy Mom and Pop stores,” explains Sherman. “Their haulers have never made the commitment to buy specialized vehicles to do a milk run. I was talking about something we’ve been doing for several years, thinking that this is old, boring stuff and people in the audience were saying ‘That’s cool, I wish we had that in our community.'”

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