My compliments to Dr. Lynton Land, who wrote a compelling commentary on manure pollution of the Bay, “Bay cleanup a waste of time unless we seriously address manure,” (December 2006). His straightforward, numbers-based approach to farm manure application in Virginia should be enough to encourage more serious attempts on the part of government agencies, environmental organizations, elected officials, farmers and citizens to challenge the status quo.
Any solution offered must satisfy all stakeholders. The broiler growers of Delmarva provide between one-third to three-fourths of their state’s farm income and are important to the communities they serve well beyond the economic value of the chickens they grow. The chickens they grow also provide valuable fertilizer to farms throughout Delmarva.
In addition to land application, there are generally three ways to deal with the manure/sludge issue: incineration, gasification and digestion. Each of these methods would be coupled with a power generation component to produce both electricity and heat for the farm and perhaps, neighbors.
Both incineration and gasification require high capital costs. In addition to the probable tax subsidies granted to lure a commercial operator, they would require the regional aggregation of manure. This would also entail the highway transportation of hundreds of thousands of tons of manure, a potential bio-security hazard.
But regional sites do not meet the test of protecting the economic interest of the grower/farmer. After all, today they get free fertilizer and under any regional approach, the subsidized commercial operator would likely exact an additional tipping fee from the farmer/grower for the removal of manure from the farm.
Why should farmers pay someone to take it and extract the valuable energy content for profit?
Manure digestion is a powerful tool for managing organic farm waste by reducing odor and pathogens while producing biogas energy and improving the environment. The methane produced from manure digestion contains 95 percent of the energy value of natural gas.
If, on the other hand, manure is applied on a field, it becomes a source of methane to the atmosphere. Pound for pound, methane has 20 times the global-warming potential as carbon dioxide. Additionally, it is well-documented that some of the nitrogen and phosphorous in land-applied manure escapes as excess nutrients to rivers and streams, causing problems for Bay grasses and increasing the size of the Bay’s oxygen-depleted dead zones.
Farm-level digestion offers an approach to this issue capable of satisfying all stakeholders.
Not often do both economic and environmental interests coincide, allowing the broiler operators to become energy independent while preserving the fertilizer value of their manure and mitigating environmental damage.
Delmarva produces nearly 800 million chickens annually that deposit more than 700,000 tons of manure on the land. A co-op of multiple farms that are digesting manure locally can generate power year round and provide heat to the broiler houses in winter.
Manure used in this manner becomes not only an economic asset but also mitigates environmental damage. The digestion process does not destroy the fertilizer value of the manure. To the contrary, the digestion process not only segregates the nitrogen and phosphorous but renders it safe by destroying pathogens. This allows the farmer to customize the nitrogen and phosphorous balance to the soil and crop, thereby reducing the nutrient overload that can happen when raw manure is applied to fields. This occurs because raw manure contains as much as four times the phosphorous that most crops need. The excess segregated phosphorous is now biologically safe enough to be labeled organic and can be sold outside Delmarva, creating yet another income stream for the grower.
Anyone accepting the foregoing as technically achievable is probably thinking: Who is going to pay? The answer is: Only the willing.
Vermont has shown the way. The Vermont Public Service Commission has approved a new rate tariff that Central Vermont Public Utility offers their customers. They have the opportunity to voluntarily donate 4 cents per kilowatt-hour (about $6/month). The money collected goes directly to the farmer involved in renewable energy. A fund has also been established that is dedicated to the construction of renewable energy facilities. One such farm level digester facility, Berkshire Cow Power, will generate 3 million kilowatts this year. (For information, visit www.cvps.com/cowpower/our farms berkshire.html.)
For those who doubt that chicken manure doesn’t contain enough energy value, I would refer them to the University of Missouri study, “Generating Methane Gas from Manure,” which concludes that on an animal pound for pound basis, poultry litter contains more energy than either dairy or swine manure.
So the answer is now at hand. The environmental data speak volumes to the need to reduce watershed nutrients. The economic incentive helps the grower/farmer. The local townships reap the benefit of the locally generated source of new income, and the capital structure can be supported by volunteer donations. What is not to like?
There are certain to be technical development issues to be overcome. That is the purpose of a demonstration beta site.
Dr. Land stated in his commentary, “scientific uncertainty is not a reason for inaction.” This is a case where the science is known; now the political will must be applied to achieve results.
As Dr. Howard Ernst stated in his 2003 book, “Chesapeake Bay Blues”: “It is clear that unless the problem of agricultural waste is adequately addressed, the overall effort to restore the Bay is unlikely to succeed.” The operative word here is “adequately.”
It is time for the state agencies, as well as the environmental organizations, some of which are largely supported by taxes, to reject the tyranny of the status quo and support the construction of a farm-level demonstration project in lower Delmarva.
I am convinced that the environmental and economic success of such a project would soon be replicated just as what is now happening in Vermont.