Irish firm tackles burning issue of Maryland’s poultry waste
State-subsidized pilot project on Dorchester farm generates energy from manure, reduces pollution
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The first thing a visitor notices when stepping inside two of Brad Murphy's chicken houses is the smell. Usually, the acrid reek of ammonia assaults the senses upon stepping into a 40,000-bird house. But in these two, there’s barely a whiff.
That’s because Murphy’s farm on Maryland’s Eastern Shore, called Double Trouble, is part of the state’s big experiment in converting animal manure to energy. An Irish firm, BHSL, has put in a $3 million system that burns the poultry waste to heat the houses.
The system curtails the ammonia fumes that not only make poultry houses stink, but compromise the birds’ health. It also can give farmers a financial boost — they can avoid paying for propane to heat the houses, and even make a little income from selling excess energy generated by the system that’s fed into the electric grid.
Maryland’s Department of Agriculture has committed nearly $3.8 million to try out a variety of manure-to-energy projects, $1 million of which went to the Double Trouble project. It’s the largest investment made by any Chesapeake Bay watershed state toward finding alternative uses for the massive amounts of animal waste generated by poultry, dairy and other livestock farms.
On a visit to the farm Feb. 13, Maryland Gov. Larry Hogan praised the Murphys for “leading the way for farmers to improve water quality, increase energy independence, and improve animal waste management to ensure the sustainability of animal agriculture in our state."
Maryland is pouring cash into the manure-to-energy effort because research has shown that the traditional farming practice, particularly on the lower Shore, of spreading poultry manure to fertilize crops has left the soils in many fields with such high levels of phosphorus that it threatens water quality.
Manure is rich in nitrogen and phosphorus, which stimulate plant growth. But while crops consume most of the nitrogen in the poultry waste, they can’t use all of the phosphorus, leaving it to build up in the soil from repeated manure applications. When phosphorus increases, it can run off in a rainstorm or seep down into groundwater. Either way, once it reaches streams and rivers, it can feed algae blooms that reduce water clarity and lead to “dead zones” in the Bay, which stress crabs and fish.
The state agriculture department has looked at soil data from 85 percent of the state’s farms and estimates 18 percent of the fields statewide are high in phosphorus. Two-thirds of the soils tested on the Lower Shore had elevated levels — that’s where most of the state’s chickens are raised. In all, state officials estimate, poultry farms are generating 315,000 tons of manure that has to be transported elsewhere or used in some other way.
For that reason, manure-to-energy projects have attracted state and federal officials. Virginia and Pennsylvania are also funding similar pilot projects. But the BHSL system is the only one determined by an independent analysis to lower air emissions while also keeping phosphorus out of the water, said Kristen Hughes Evans, executive director of Sustainable Chesapeake. The nonprofit group is coordinating the manure-to-energy initiative for the Bay watershed states.
“It looks like one of the cleanest technologies that we have been able to find,” Evans said. “When you walk into one of the houses that is heated, you can see clear to the end of the house. That is good for the birds, but it’s a big environmental benefit, too.”
In a tightly controlled experiment, two of Murphy’s chicken houses are using traditional propane heat, and the manure the birds produce is cleaned out every six to eight weeks and hauled away to area farms for fertilizer. But in the other two, the poultry litter — a mixture of manure and wood shavings — is kept on site and burned to generate heat and electricity. The University of Maryland is tracking the data.
At the Murphy farm, workers take this litter and deposit it just inside the building housing the BHSL system. From the outside, the building looks like a typical manure shed, but it’s attached to a larger building.
A sensor tells when a load is ready for pickup, and a top loader — a mechanized shovel attached to a pulley-like apparatus on the ceiling — scrapes up the litter and places it on a conveyor belt.
The belt then feeds the litter into a furnace much like any large commercial boiler. But in this one, the litter is burned over a bed of hot sand, with jets of compressed air blowing through the chamber to break it up. The combustion warms water to 250 degrees Fahrenheit, which is piped into the houses to heat them. In warm weather, the hot water can be diverted to an absorption chiller to cool the birds. In times when the houses need little heat or cooling, the excess energy from burning the litter can be used to generate electricity, which the farmer can sell to the grid.
The ash left behind from the combustion has high levels of phosphorus. But unlike the litter — which because of its bulk is expensive to haul away — the ash is more compact; every 10 tons of manure yields one ton of ash.
That concentrated ash has commercial potential as an ingredient in fertilizer, BHSL founder Declan O’Connor said. A Virginia Tech study indicated it could be good for growing tomatoes, but the company needs to see if it will be competitive with other products.
The system offers one other significant benefit, in addition to protecting waterways from pollution and giving farmers income from selling their energy and the ash. It cuts down on ammonia fumes, which has implications for farmers’ bottom line and the environment.
Poultry farmers typically heat their shed with propane burners. But burning the gas generates a significant amount of water in vapor form. The moisture in the air reacts chemically with the nitrogen in the birds’ urine to create ammonia.
Farmers typically deal with the buildup of ammonia fumes by ventilating their houses with large fans. But that doesn’t eliminate the odor inside, and it emits ammonia into the air outside. Ammonia is a harmful pollutant that if inhaled at high enough levels can burn nasal and bronchial passages and cause other health problems. And even at lower levels, it’s often washed out of the air by rainfall, adding to the nitrogen being flushed off the land and into waterways and the Bay. The ammonia emissions of poultry farms are not regulated or even monitored, but a bill has been introduced in the General Assembly this year that, if passed, would change that.
The BHSL system warms the houses indirectly, via piped-in hot water. As anyone who’s lived in a home heated by radiators can tell, it’s a dry heat. With no moisture generated inside the houses, there’s nothing extra to react with the birds’ waste, so there’s far less ammonia stinking up the houses or being vented into the air outside.
Breathing less ammonia should be better for the chickens, as it lowers their stress and aids their digestion. It can also help the farmers, because unstressed birds don’t need as much feed to grow and put on weight. More efficient nutrition for the birds can be good for the planet as well; according to the United Nations Food and Agriculture Organization, feed production accounts for 78 percent of the greenhouse gas emissions associated with raising poultry.
“We’re doing good. This is good for the environment. It’s good for the chickens,” O’Connor said. “But we have got to figure the business model out. This is not done.”
There are some significant hurdles before this system would be feasible for most farmers. One is logistical: BHSL manufactures its poultry burners in Ireland, and the system shipped to Murphy’s farm took six months to put together, requiring more than two-dozen contractors. O’Connor said that he hopes future systems will not only be assembled here, but also built on the Eastern Shore, adding hundreds of jobs.
A bigger issue is the system’s cost to build. The initial $3 million price should come down if components can be made locally and assembly can be simplified to streamline a months-long project that makes an IKEA dresser seem easy. Even so, it is still likely to cost a farmer several hundred thousand dollars.
“These things are not affordable for the average farmer,” said Bill Satterfield, executive director of the Delmarva Poultry Industry Inc., which represents poultry companies and growers. “But if they work, great. More power to them, so to speak.”
BHSL is going to have to convince the poultry companies, which now supply the propane to their growers, that it’s worth the upfront expense to install on-farm boilers like Murphy’s and retrofit their houses with radiator-style heating.
Brad Murphy thinks it’s worth it. In his propane-heated houses, ammonia concentrations are 40–50 parts per million, and the smell is intense. At levels that high, experts say, the mucous membranes in the birds become damaged, and they are susceptible to infections. In the houses heated with the BHSL system, ammonia levels have been reduced to 25 ppm. Ideally for birds’ health, he said, the levels should be even lower, 20 ppm.
“Whatever we’re doing now, it will be better in the next month,” he said. “We’re only four weeks into it so far, and look at the result.”
It’s taken Maryland seven years to get to this point. Though Pennsylvania has been digesting dairy manure since the 1970s, until now no one has succeeded in turning chicken manure into energy without producing unacceptably high air emissions.
In 2011, the Chesapeake Bay Commission sponsored a manure-to-energy summit in Maryland to discuss the potential of new technologies. A representative from BHSL was there, and he later invited members of the tri-state legislative advisory body to see a plant in England. Several Maryland policy-makers made the trip, including Sen. Thomas “Mac” Middleton.
“It has huge, huge potential,” Middleton, a Charles County Democrat who is the Maryland Senate’s only full-time farmer, said of O’Connor’s system. “And these are very dedicated people.”
Like Maryland, the United Kingdom has a poultry problem. But the issue there is mainly with the nitrate produced by the animal waste, not the phosphorus.
In 1996, out of concern for its drinking water, the United Kingdom placed 8 percent of its land in “nitrate vulnerable zones” where the government restricted how much manure farmers could apply. In December 2000, the European courts ruled that the United Kingdom also needed to protect ground and surface water, and increased the vulnerable zones to 47 percent of the land.
By 2002, nitrate-vulnerable zones were the law all over Europe. Suddenly, farmers like the O’Connor family, who had raised poultry for decades in Limerick, had no place for their manure.
O’Connor worked with engineers, technologists and farmers to find a solution. Since 2006, five BHSL systems have been installed on farms in the United Kingdom. Six more will be finished by March.
O’Connor said that he believes that a law change in 2014 that re-classified manure as a fuel and not a waste has opened possibilities in Europe for both the systems and the byproducts, which help to offset the costs. He hopes that change will come in the United States as well, but notes it took three years in Europe.
It’s not clear yet how much demand there’ll be in Maryland for converting poultry manure to energy. Soil test results submitted to the state agriculture department suggest the problem with phosphorus-saturated fields may not be as severe as initially believed.
And not every project will succeed. The O’Malley administration granted a contract to a California company, Green Planet Power Solutions, to build a $75 million plant on the Shore capable of generating power from 175,000 tons of manure annually. But the company had never built such a facility, and the project never came together. The Hogan administration canceled the contract.
State agriculture officials say soil tests show the Shore has enough acreage low in phosphorus to accept the excess manure. But the poultry industry’s Satterfield said many farmers prefer not to use litter because of the additional regulatory and other requirements.
So, the department has continued to invest in manure-to-energy technologies. In September, it awarded $1.4 million to another company, Clean Bay Renewables, to build a plant that could process 80 tons of manure daily and generate 2 megawatts of electricity. It has another $3 million available to invest this year.
The next project likely to come online is in Pocomoke City, where a company called Planet Found has developed a system to turn 1,250 tons of manure a year into energy through anaerobic digestion. The nitrogen is consumed in the process, and the remaining phosphorus can be used in commercial soil additives. Technical director Andy Moss, who has a graduate degree in environmental science with a focus on anaerobic digestion, said the local investors behind Planet Found are wary of promising more than they can deliver.
“We’re trying to be very methodic(al) about our approach to this in not biting off more than we can chew,” he said. “We have to find profit in this, and that is and will continue to be one of our biggest challenges.”
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