Background

Water quality in both the Shenandoah River and the Chesapeake Bay is degraded as a result of excess nutrients from many sources, including animal agriculture. In July 2003, the Bay suffered one of the largest “dead zones” – areas of oxygen depletion – since the federal government began monitoring oxygen levels 20 years ago. While agriculture is not the only source of nutrient and sediment loss, the industry clearly has a role to play in cleaning up the Bay.

Finding solutions to manage the excess manure and litter in the Shenandoah Valley is critical to the area’s economy, environment, and society. Dairy farming in Virginia generates $300 million in farm receipts, and 40 percent of the state’s dairy farms are located in the Valley. Poultry and eggs are Virginia’s top agricultural sector, directly supporting about 1,200 families, 76 percent of which live in the Valley.

In light of the Chesapeake 2000 Agreement and nutrient reduction needs, the Valley offers a key opportunity to implement innovative solutions to excess manure and litter nutrients. It is clear that small-scale efforts, traditional BMPs, and farm-by-farm strategies will not get the job done. To address this challenge, a diverse group of stakeholders came together in April 2005 for the Waste Solutions Forum in a grassroots effort to determine the most effective means to manage excess animal manure and poultry litter in the Shenandoah Valley. Strategies agreed on by the forum included:

•Redefining animal waste as Valley Organic Resources.

•Avoiding options that rely heavily on long-term government subsidies.

•Emphasizing options that provide additional economic benefit to the farmer.

Several pilot technologies and approaches were identified as priorities during the Waste Solutions Forum (WSF)—specifically, technologies that create usable energy from animal manure and poultry litter while also reducing nutrients by sequestration and transportation out of the watershed. Pyrolysis is a promising technology for use with poultry litter, and struvite crystallization for use with dairy manure. Priorities from WSF also included expansion of markets for sale of poultry litter and composted materials to provide economic return to the farmer while reducing over-application of manure and litter to farmland.

Katharine Knowlton1, Greg Evanylo2, Jactone Arogo-Ogejo3, Foster Agblevor4, Conrad Heatwole5, Eric

Bendfeldt6, Kathy Holm7, and Rebecca Barlow7

1. Associate Professor, Dairy Science, Virginia Tech 2. Professor, Crop and Soil Environmental Sciences, Virginia Tech3. Assistant Professor, Biological Sciences Engineering, Virginia Tech 4. Professor, Biological Sciences Engineering, Virginia Tech 5. Associate Professor, Biological Sciences Engineering, Virginia Tech6. Area Specialist, Community Viability, Virginia Cooperative Extension 7. Coordinator and Market Maker, respectively, Shenandoah RC&D Council

Objectives

This project will target the North River Watershed of the Shenandoah Valley, where we propose to overcome the manure challenge by

1) generating revenue from manure on poultry farms via bioenergy production

2) decreasing the cost of manure transport through nutrient isolation and concentration technologies

3) increasing markets for manure and poultry litter

4) demonstrate the value of manure-and litter-based compost and mulch

5) assess cost-effectiveness and impact on nutrient loads

PYROLYSIS: break-down of organic materials using high temperatures in the absence of oxygen

Process: involves heating poultry litter to 400-500ºC, resulting in three products

Products: 1) condensable vapor a. condensed into bio-oil (pyrodiesel) b. can be used for fuel 2) non-condensable gases3) solid charcoal residue a. 30-40% of original weight of poultry litter b. contains high levels of N, P, potassium, and calcium c. can be used as a fertilizer

Outcomes

Pyrolysis: When the project is fully implemented, we expect to convert at least 100,000 tons of litter per year to pyrodiesel and other products, removing 5.8 million pounds of P and 5 million pounds of N from the Bay watershed.

Struvite Crystallization: Using struvite crystallization on individual farms, 122,000 pounds of P and 12,000 pounds of N will be isolated for marketing out of the watershed per year. With implementation of a community shared digester, an additional 142,000 pounds of P and 14,000 pounds of N will be removed.

Market Maker: In addition to creating markets for the pyrolysis char and struvite, the market maker will develop markets to move an extra 200,000 tons/yr of litter from the watershed.

Compost Demonstration:Compost application will benefit 1,000 acres of

disturbed land in the Shenandoah Valley and 80 acres of wildflowers. At an application rate of 1 to 2 inches, 1,332,000-2,660,000 lbs N/yr and 888,000-1,766,000 lbs P/yr will be removed.

Innovative and Cooperative Approaches to Utilize and Export Shenandoah Valley Organic Resources and Reduce Nutrients to the Bay

Funding for these projects was obtained from the National Fish and Wildlife Foundation.

Post-Project Potential Nutrient Removal

Technique N (lbs/yr) P (lbs/yr)

Pyrolysis 5 million 5.8 million

Struvite 26,000 264,000

Marketing 11.6 million 11.6 million

Total 16,626,000 17,664,000

Poultry LitterPYROLYSIS500ºC no O2

CONDENSATION

Bio-oil

Gases

COMBUSTION

Char

APPROACHES

STRUVITE CRYSTALLIZATION: precipitation (removal) of phosphorus from liquid dairy manure

Process: involves adding magnesium to dairy manure and adjusting pH to cause formation of struvite crystals, or MgNH4PO46H2O

Product: white crystalline powder known as struvite

Uses of struvite: 1) as slow release fertilizer 2) in manufacture of cleaning products 3) as raw material for phosphate industry 4) in making fire resistant panels 5) as binding material in cements

Dairy Manure

Anaerobic Digester

Fluidized BedReactor

Struvite

Biogas

Stored Effluent For Land

Application

MARKET DEVELOPMENT: pilot a position of full-time organic byproducts manager

“Market Maker”•Aggressively identify new markets for organic byproducts

•Including byproducts from new technologies

•Help develop literature and/or websites for use by farmers to market organic resources

• Benefits of organic byproduct application•Current incentive programs

•Coordinate with the VPF to create and maintain a database and operate a byproducts ‘hotline”

•Match buyers, haulers, and sellers of Valley organic resources•Improve sales and utilization through accessibility•Help introduce new product ideas

•Assist with new research and development efforts•Add value to Valley organic resources with techniques such as composting and pyrolysis•Work toward goal of converting 1/3 of Valley poultry litter to energy and char fertilizer annually

•Conduct workshops and educational programs•Reach out to those not using organic byproducts who could•Inform the public about community-shared digestion and pyrolysis units

VIRGINIA POULTRY

LITTER HOTLINE

Announcing our New Number!

1-800-418-0768

The hotline is supported by the Virginia Poultry Federation and operated by Becky Barlow, Market Maker. It was created to help connect poultry growers in the Shenandoah Valley with litter buyers and haulers throughout Virginia.

COMPOST USE: work with VDOT to identify locations for studies on restoring disturbed land using compost produced from Valley poultry litter and manure

•Compare composts with hydroseeding and silt fence for revegetation

•Compare costs of compost versus standard practices

•Compare N, P, and sediment runoff under compost and standard practices

Assumptions: Recommended compost application rates for erosion and sediment control, and for soil quality enhancement for wildflower establishment and turfgrass revegetation, are 1 to 2 inches thick.

One inch of compost = 134 cubic yards/acre or74 tons/acre (@1100 lbs/cy)

At 60% solids content, 1 inch compost supplies 88,800 dry lbs per acre.

Poultry litter- and livestock-based composts typically contain 1.5% N and 1.0% P.

ASSESSMENT: use watershed modeling studies to quantify expected long-term nutrient reductions under a variety of scenarios

•Analysis based on best-available field data•Detailed watershed characterization•Farm-specific nutrient budgets•Stream monitoring data of flow and water quality

Goal of simulations: compare mean annual nutrient loads from watershed for baseline condition and variety of treatment scenarios

•Assess cost effectiveness•Propose and evaluate alternative scenarios•Establish feasibility for nutrient trading•Compare costs of implementation at watershed and regional levels