BioCycle November 2009, Vol. 50, No. 11, p. 21
Simple composting system enables a dairy farm to diversify operations.
Laurelbrook Farm is a third-generation dairy farm in East Cannan, Connecticut. The Jacquier family owns 275 acres, and rents an additional 2,500 acres for cropping, to support a herd of 830 cows. The family began composting three years ago as part of the farm’s nutrient management plan, as well as to determine the market for compost in the area.
“In 2003 the Environmental Protection Agency (EPA) released Confined Animal Feeding Operation (CAFO) regulations, and an advisory board was put together in Connecticut,” recalls Bob Jacquier of Laurelbrook, which is considered to be a CAFO. “Studies were conducted on nutrient management for the state to determine how many acres were available for manure spreading. Based on the results, which showed that there wasn’t enough land, we decided to investigate composting as an option for managing and exporting our nutrients.”
Besides regulatory issues, the Jacquier family had several other interests in exploring composting. The cost of transporting manure for land application was climbing, in part because of odor concerns in the rapidly populating area. “We also wanted to enter a value-added market,” says Jacquier. “The price for milk is set by the market, and has been declining in recent years. With composting, we’ll be able to charge a tip fee for incoming materials, and produce a valuable soil amendment.”
The farm initially began composting using a bucket loader to turn material on a gravel pad. Once it was determined that composting was a viable business plan, the Jacquiers applied for and received grant funding from Connecticut Department of Environmental Protection (CT DEP), EPA Nonpoint Source Pollution Control Program and the Environmental Quality Incentives Program (EQIP) of the Natural Resources Conservation Service.
“We issued an RFP for alternative technologies or utilization of dairy manure that would reduce the surplus of land-applied nutrients,” says Joe Wettemann of CT DEP. “Laurelbrook was awarded $1,124,000 for buildings, turning equipment and an impervious surface.” In Connecticut, explains Wettemann, farms are allowed to compost manures under their approved comprehensive nutrient management plan, so long as it is considered integral to the farming operation. However, the composting operation must be covered, either by windrow covers or in a building.
Laurelbrook decided to install four fabric buildings for its composting operation, with a total of 75,000 square feet. The buildings, designed and constructed by ClearSpan, are highly resistant to corrosion, with trusses made of Allied Gatorshield steel tubing and duraweave fabric covers (see “Buildings and Corrosion Control,” BioCycle October 2008).
The buildings are all standard Hercules Truss Arch models, but customizable features helped to save the farm money, and improve performance. The Jacquiers chose not to have electricity, instead relying on natural light and natural ventilation. To increase airflow, the end walls were left open, and ridge vents were installed on the top. “We also decided to not run the covers all the way down, instead raising them two feet off of the ground, allowing for increased draft to the top of the building,” says Joe Teixeira, a Truss Arch Specialist with ClearSpan, who oversaw the project. “An asphalt floor was installed instead of concrete, using our proprietary ground anchor system to secure the building, resulting in a savings of about $800,000 for the project.”
The cost savings were primarily due to materials, because asphalt was cheaper at the time, but also in labor, considering that minimal excavation was needed, and hours weren’t spent laying forms and pouring concrete. “One of the biggest benefits of using our fabric structures for on-farm composting is that they provide an operation sympathetic to neighbors,” says Barry Goldsher, President of ClearSpan. “Laurelbrook is a pristine 800-cow farm in a high-end area of Connecticut, and our buildings not only perform well, they fit in with that motif, instead of looking industrial like a factory.”
Manure is collected in a 90,000-gallon pit centrally located under the dairy barns, which allows for approximately three days of storage. The manure is pumped to a roller-press separator, resulting in solids with about 75 percent moisture. The liquid effluent is pumped to a slurry storage tank, and is later land applied.
The tipping shed is 60 by 80 feet, and is used for receiving raw feedstocks, currently about 750 yards per week. “Besides the separated manure, we also compost bedding from our maternity and hospital barns, which is straw and sawdust and high in carbon, as well as waste corn silage,” says Jacquier. “We accept wood chips from the community and horse bedding from neighboring farms. Eventually we want to take food waste, but first we need to make sure we can smoothly compost our own feedstocks.”
About once a week, the raw materials are moved to one of two active composting buildings, which are each 100 by 250 feet. Either a loader or a live-bottom belt trailer made by Red River is used for transporting the material. “Each active composting building has space for five windrows, which we turn using a Backhus 1755 turner,” explains Jacquier. “We actively compost for a period of eight weeks, with turning depending on temperatures – three times per week when the temperatures are high, and then once a week as the temperature cools.” Handheld Reotemp thermometer probes are used.
The compost is then moved to the finishing shed, which is 80 by 200 feet, where it is cured for four to six weeks. ”Everything that leaves our facility is screened to a half inch using our 620 Powerscreen,” says Jacquier. “We also use the Solvita test before selling our product, to give a guaranteed product.” Laurelbrook exclusively sells the compost in bulk, but has plans to begin bagging when the product is consistent and a market is established. “We’ve only been composting since early February,” he continues. “Within a year or two we’d like to manufacture topsoil and garden mixes.”
Jacquier notes that the fabric structures have allowed his composting operation to remain simple: “Simplicity is the key to our success. We don’t have specialized turners or complicated aeration systems that can malfunction, just a straightforward and simple process that fits in with our farm.”
In the future, Laurelbrook would like to further clarify the liquid effluent to remove more phosphorus. “We’re looking at centrifuges, and possibly a chemical process, to extract more phosphorous from the liquid fraction after the manure goes through the separator,” he says. “This phosphorous would be added to the composting process in separate windrows to create a richer fertilizer, which we could sell to golf courses, and other high-end markets.”
Wettemann explains that beyond creating a more valuable fertilizer, pulling phosphorous out of the liquid effluent is in accord with the state’s nutrient management plan. “The benefits of adding this step are two fold: it reduces the concentration of phosphorous in the effluent that will be spread on agricultural land, allowing for a higher application rate based on nitrogen needs of the crop; and it reduces the nutrient surplus on the farm by redistributing the nutrients in the finished compost off the farm,” he says.
Laurelbrook has also been considering installing an anaerobic digester, which would be located next to the composting operation. “There are three farms within a mile and a half, so it would be a 2,000-cow, community digester, plus food waste for better biogas output,” says Jacquier. “Anaerobic digestion is just another piece of the puzzle, extracting energy out of the materials as well as providing nutrients for the soil.”