Can composting provide the answer to liquid and dry manure disposal?

by DON STONEMAN

Both companies are developing new technologies to deal with growing concerns about livestock manure and the environment. Both are fighting the tide of conventional thinking about how to deal with manure. And both are finding it an uphill fight, with victories matched by daunting setbacks.

When he was president of the Canada Pork Council in the early 1990s, Global Earth's founder, Tom Smith, realized that dealing with liquid manure was a growing international problem. A former Simcoe County pig farmer, he has spent nearly a decade developing a manure-composting unit called "The Marvel."

The machine is mounted on top of a six-foot-high, 12-foot-wide concrete channel filled with manure and straw. Twice a week, it churns up a mixture of manure and organic material, straw, wood shavings or even waste pulpwood products. For three minutes every hour, fans push air into the mixture through an aerated floor to provide oxygen for the composting process. Excess liquid drains back through the channel to the barn manure tank. One volume of straw holds six volumes of liquid manure.

The composter is housed either in a conventional building or a "soft top" shelter to shed rainwater and keep temperatures within a particular range The Marvel is wired to the backup diesel generator in a hog, poultry or dairy barn. The fans run for three minutes per hour on regular barn 220 power.

John Stolp, who raises roughly 12,000 turkeys at a time in his barns near Brantford, is an enthusiastic proponent. Though he farms 28 acres, his birds produce enough manure to rotationally spread on 300 to 400 acres and for years Stolp has depended on other individuals to haul it away. He looked at the composter first as a means of manure disposal and, second, as a revenue generator. "It wasn't costing us to have manure hauled away, but we weren't getting anything for it," he says.

Midway through the second year of composting, Stolp has found success on both fronts, selling his compost to four local golf courses. There's potential also in gardening centres and landscape contractors, but golf courses are the best bet for now, he says. "As an industry, they are facing a lot of pressure to follow nutrient management guidelines."

Smith says Global Earth will buy back the compost from farmers and market it under the Utopia Gold label. At this point, he is valuing compost at $30 per tonne, the same value as compost sold from landfill sites, but he expects the price to go up. Landfill compost tends to be high in organic matter and very low in fertility.

At Ridgetown College, scientist Ron Fleming has tested the Marvel with a variety of livestock manures and carbon sources, including mixing liquid pig manure and solid beef manure, and he is a strong supporter of the process.

Compost from Ridgetown College is being spread on demonstration plots near Drumbo, in Oxford County. Chris Brown, a nutrient management field crop specialist with the Ontario agriculture ministry, says the compost has been applied to a field at the rate of 13 tons of 25 per cent dry matter per acre. Nitrogen varies from 15 to 30 pounds per ton, P at five to 12 pounds, and K at 15 to 30 pounds per ton. Nutrient density is about twice that of regular manure, and the volume to take to the field is about half.

Smith predicts that, with nutrient management plans becoming mandatory, some operators will find it hard to maintain their livestock base on their current land holdings. Composters like this may replace a land purchase for farmers who don't have a place to put their phosphorus output. Another benefit: a smaller manure storage is required, perhaps as little as three months worth.

Smith has also developed a version for smaller livestock units. A composter that would handle manure from 50 dairy cows or a comparable number of pig animal units costs about $100,000, including the composting machine, the building and the channels. A unit to handle more than one million gallons of liquid manure would cost around $250,000. There are economies of scale with larger operations, Smith says. A single mixing machine would work on more channels, in a larger building.

Compost windrowers
Kerr Farms at Chatham started composting straw-bedded manure from its 1,000-head feedlot in February. Bob Kerr has about 500 tons of compost in windrows ready to go on harvested tomato fields this fall. Following application, a cover crop of oats will be planted. The volume of compost is about half the normal volume of manure that the feedlot would produce.

Even though Kerr Farm fields have received manure for 31 years, organic matter levels have held barely steady, and Bob Kerr would like to see them increase. He has invested $16,000 in a turner, $14,500 in a spreader, and traded in another tractor to buy a used IH MX135 with a creeper gear and mechanical front wheel drive. The creeper is necessary to maintain a 20-feet per minute speed when turning the compost. He's also purchased a number of fleece covers, used to maintain moisture and temperature in about a dozen windrows as long as 250 feet. The windrows are 11 feet wide and about five feet high.

The compost turner and spreader are made by Sittler's Manufacturing at Linwood, and marketed through Global Repair in Mississauga.

There are a host of compost windrowers on the market. One reported in Better Farming earlier March 2001 is the Scarab, produced by Scarab Manufacturing in White Deer, Texas. Scarab's marketing manager, Sam Hill, says the self-propelled Scarabs come in various sizes and range in cost from about $100,000-350,000 US. It's the machine of choice for Alberta-based Agricore, which contracts with feedlots in the Lethbridge area to compost and haul away steer and heifer manure for sale as a supplement for lawns and gardens.

So why shouldn't a number of farmers share a Scarab to do the job that Smith is talking about? Smith says he is reluctant to slam competitors, but he asserts that windrowing on a concrete slab outdoors is open to harsh weather. Rain can leach off nutrients and cool off the windrow so that it is no longer composting properly.

Pennsylvania composting advocate and guru Larry Breech disagrees. Breech uses a compost windrower on his farm operation, where rainfall and bad weather take a toll as it does here. Where he and Smith do agree is that composted manure is worth more than the N, P and K value in the fertilizer. Breech acknowledges that composting takes good management, including regular mixing to give it oxygen. Lack of oxygen during the composting will produce an undesirable product that is worse on fields than no compost at all, he says, because it can become a toxic mess.

Composting is no more expensive than handling liquid manure, even with larger operations, Breech asserts, citing a Michigan State University study that compared the cost of composting manure from 120 dairy cows to spreading it with a liquid manure system. But the jury is still out on composting as far as a skeptical Sam Bradshaw is concerned. Ontario Pork's environmental officer thinks composting may be too much to manage for already busy farmers.

Bradshaw has high expectations for an experimental two-storey solid manure pig barn near Exeter. That barn, completed last fall, combines the advantage of low-labour liquid manure systems and solid manure that is less likely to run into field tiles than liquid manure. The first year's manure from the barn was spread in late summer. Ridgetown's Ron Fleming says evaluation should be finished by the end of October. BF

In the fall of 1999, following environmental disasters in the hog-heavy state of North Carolina, Forbes published an effusive article about publicly-traded Bion Environmental Technologies Inc. Bion claimed that it could purify the liquids from manure from large-scale livestock operations and turn the solids into special soil and fertilizer products that could be marketed in garden centres.

The process involved moving effluent from large-scale livestock operations into settling ponds, and then pumping the remaining liquid onto man-made wetlands.

With concern growing about the huge amounts of liquid manure that come from large hog operations and also the dairy feedlots in California, the possibilities seemed endless for the publicly traded company.

In spite of Forbes' endorsement, it has been a rocky road for Bion. In April, 1999, the company announced that it had signed a contract to design and operate a waste treatment plant for a 1,600-cow dairy in Wyoming County, southeast of Buffalo, N.Y. Since then the dairy and another Bion test location in the same area have shut down, but the company is soldiering on.

Bion's newest system, which it is hoped will reduce the space needed to treat liquid manure by 80 per cent, is being tested at Dream Maker Dairy, a defunct dairy southeast of Buffalo. A $150,000 monitoring unit in a trailer near the well-worn heifer barns measures effluent from a group of heifers. The manure is flushed out of the barn at regular intervals, solids are removed and the remaining liquids are moved into tanks and tested for emanations.

Jere Northrup, Bion's chief technology officer and the system's developer, says the information will be passed on to the federal Environmental Protection Agency and the state Department of Environmental Conservation for evaluation. Northrup says the water coming from the treated effluent is so clean that Bion has permission to dump it into a watercourse.

The tanks mimic what happens when liquid from the Bion system is spread on man-made wetlands at the back of the 98-acre Dream Maker farm. Liquids are pumped from "cells" (a term preferred over the pejorative "lagoon") onto raised wetlands where they filter through and nutrients are taken up by vegetative growth.

In the first generation of Bion's technology, an acre of wetland was needed to deal with the manure from 100 cows. Using the new "tank" technology, Northrop maintains that the effluent from 5,000 cows can be disposed of on three to four acres of farmland.

Northrup says a 20,000-gallon system of three tanks will handle the manure from as many as 100 dairy cows. A half-million-gallon system would take care of effluent from 1,500 dairy cows, typical of a dairy in California where there are growing concerns about odours and flies on large-scale operations.

Unfortunately, most of Ontario's livestock operations aren't big enough for this technology, which requires a minimum of 300 cows. Grant Kennedy, quota manager for Dairy Farmers of Ontario, says that out of 7,000 dairy farms in the province, there are only a dozen holding more than 285 kg of quota. (A kilogram of quota is roughly one cow's production.)

The pork industry might be better able to use this technology, says Keith Robbins, Ontario Pork's director of communications. Most feeder operations are only 2,000 hog capacity but sometimes there are multiple barns on one site. As well, a handful of beef feedlots might fit the Bion model. But then there is the matter of marketing the trademarked "Bion" soil.

In spite of criticism, Bion plugs on. The company has been trying to improve its profile by adding some hefty names to its' advisory board, among them former U.S. agriculture secretary Dan Glickman and Victor Lechtenberg, Dean of Agriculture at Purdue University. Bion has also hired a professional lobbyist in Washington.

Ed Henning, Bion's vice-president of business development, says he never dreamed that he would spend so much time fighting with agricultural extension people in the United States who don't share the Bion vision. BF