Jactone Arogo Ogejo and John Ignosh ; Virginia Tech Stephanie Lansing and Gary Felton, University of Maryland

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1 Anaerobic Digesters an Overview Jactone Arogo Ogejo and John Ignosh ; Virginia Tech Stephanie Lansing and Gary Felton, University of Maryland

2 Focus of presentation Biomethane production through anaerobic digestion of organic matter Source:

3 Biomethane What is it? It is similar to natural gas Part of biogas produced through anaerobic digestion of organic matter Methane Structure Biogas Composition ~ 55 to 80% methane (active ingredient) ~ up to 35% carbon dioxide and other trace gases (e.g. hydrogen sulfide; water vapor) Energy content ~ 55 to 80% of natural gas

Industries; Cafeterias e.t.c.) Garden waste Sewage

4 Biomethane How is it Produced? Feedstock Sources Animal manure Municipal wastes (organic) Food waste (Processing Industries; Cafeterias e.t.c.) Garden waste Sewage sludge Energy crops e.g. corn silage, beet Anaerobic Digestion Process Acid Forming Bacteria Methane Forming Bacteria Feedstocks Proteins Carbohydrates Fats Organic Acids Biogas

5 AD: Byproducts and Utilization USE Organic Material Anaerobic Digester Biogas Electricity Heat Pipeline grade gas Transportation fuel Renewable Energy credits Carbon credits Effluent Solid & liquid Fertilizer Compost Bedding Biofuel

Example biogas options in the US and Virginia Dairies Capital Cost of Anaerobic Digestion Systems? Fuel Cost Comparison SOURCES: AgSTAR Anaerobic Digestion Capital Costs for Dairy Farms - Feb.

6 Example biogas options in the US and Virginia Dairies Capital Cost of Anaerobic Digestion Systems? Fuel Cost Comparison SOURCES: AgSTAR Anaerobic Digestion Capital Costs for Dairy Farms - Feb An Analysis of Energy Production Costs from Anaerobic Digestion Systems on U.S. Livestock Production Facilities NRCS, 2007 Little information about dairies with < 500 cows Projected average size 120 cows Would biogas make sense for farmers in central Shenandoah Valley use diesel generators for farm s electricity needs Is there an opportunity here? What about nutrient management issues?

7 Dairies Operating in the U.S. Herd Size (Head Cattle) Number of Farms in 2006 Percent of Total Farms , % , % , % , % , % , % 1,000-1, % 2, % Total 75, % 71,997 Farms, or 95.8% of the Total Adapted from: USDA, NASS Farms, Land in Farms and Livestock Operations

8 Over 20,000 worldwide Large-Scale Anaerobic Digesters United States Austria China (2000) Germany China (2009) Burns, Current State of Manure Anaerobic Digestion in the U.S. and Beyond. Energy Production from Anaerobic Digestion of Dairy Manure. Madison, WI. September 28-29, 2009

9 Over 40 million worldwide Small-Scale Anaerobic Digesters United States Africa S.E. Asia Latin America India China (2000) China (2009) Burns, Current State of Manure Anaerobic Digestion in the U.S. and Beyond. Energy Production from Anaerobic Digestion of Dairy Manure. Madison, WI. September 28-29, 2009

10 The Growing Market

Asia, Southern Africa, & Latin America (Buxton & Reed, 2010)

11 Small-Scale AD Globally China and India lead the way Increased economic viability Spreading widely throughout Asia, Southern Africa, & Latin America (Buxton & Reed, 2010) Cold-climate, small-scale AD lags behind Most projects promoting concept

12 International Small-Scale AD: Numerous Designs All attempting to minimize cost & maximize performance

13 Numerous Feedstocks Primary wastes Animal & livestock manure Food waste Secondary wastes Human manure Agricultural waste Sources: (Akinbami, 2001; Bi, 2006; Voegeli, 2008) Photo Credits: (U.S. NRCS, Jean Ryder,

14 Use of Products Biogas Primary: Cooking, Heating, Lighting (Munyehirwe & Kabanda, 2008; Mi, 2007; Singh & Sooch, 2004 ) Secondary: Electricity (Lansing et al., 2008) Effluent Fertilizer Feed Solids Compost

15 Taiwanese- Taiwanese- Chinese fixed-dome Floating Drum

16 Floating dome/floating bell Indian model Mixed Waste Waste movement due to hydrostatic pressure Internal divider designed to prevent short-circuiting High maintenance (Buxton & Reed, 2010; Lawbuary, 2006; Singh & Sooch, 2003)

17 Chinese model designs vary Janata and Deenbandhu (Buxton & Reed, 2010; Khoiyangbam et al., 2004; Singh & Sooch, 2003) Mixed waste Less maintenance, longer lifespan (Buxton & Reed, 2010; Singh & Sooch, 2003) Fixed Dome

18 Plug-Flow Bag Digesters Widespread Intended for higher solids waste Waste moves in plugs Cheap, but history of problems w/integrity (Lansing, 2010; Eaton - IRRI Mexico, 2009)

19 Taiwanese Model Digesters

20 Costa Rica digesters Tubular Polyethylene Plastic Bag No Mechanical Parts Simple to build and operate Low-cost ($ )

21 Covered Lagoon Low maintenance No heating Lower biogas production, esp. during winter Wonderful for odor control

22 Predominant challenges Lack of skilled technicians Construction Maintenance/troubleshooting Blockages within systems Solids accumulation & associated maintenance Lack of engineering knowledge for upgrading Photo source: AIDG Sources: Munyehirwe, 2008

23 International Trends Mass production of proven designs Higher quality materials HDPE, Fiberglass Household and small-community units

24 International Trends Diagram credit: Mi, 2007 Integrated farming systems (Mi, 2007; Todd, 2006; Marchaim,1992) Increased government subsidies (Mi, 2007)

25 Digesters in Cold Climates Gas production drops with decreasing temperature Increased retention time Leads to increased size/capital requirements Maintenance of digester temperature Leads to higher energy inputs/sophistication of equipment Additional insulation

26 Trend: Adaptation of tropical models Credit: Aziza Kenya Credit: Jay Martin -OSU

27 University of Maryland - Small-Scale Plug Flow Setup Influent pre-heated Effluent recirculated & reheated Digesters insulated & buried Hot water circulation for additional heating

separated manure Contribution of effluent recirculation Small-scale vs.

28 University of Maryland Project: Small-Scale Plug Flow Aims of research Economic analysis Energy yield & system function: unseparated vs. separated manure Contribution of effluent recirculation Small-scale vs. Continuous Stirred-Tank Reactor (CSTR) on same substrate Emergy modeling

29 Additional Small-Scale Research in the U.S. Ohio State University Modification of Chinese fixed-dome digester Designed for small family/farm use Also looking at effluent recirculation

30 Additional Small-Scale Research in the U.S. University of Wisconsin - Platteville Compost heated plug-flow digester

31 Small-Scale Digestion Companies

32 AD in VA What is the answer? Co-Digestion or Comingling Centralized AD System Improved process efficiency New technology

33 Example: Central Shenandoah Valley County / Value $1,000 Shenandoa Valley Rockingham Page Augusta Source: USDA-NASS 2002 Census of Agriculture

34 Identify and map sources of organic residues who, what, and where? develop map that shows relative distances of sources Determine the quantities of organic residues how many pounds? What is in the composition of the organic residue Screen for biomethane production potential Nutrients

35 Determine the optimum mix of organic materials to produce maximum quality and quantity of gas Many dairies, but smaller than the size required for a conventional AD system Combine the high volume, homogenous poultry processing waste streams with manure from surrounding dairies to generate more biogas per unit volume of digester

36 The Chesapeake Bay Watershed TMDL Source: Chesapeake Bay Program 36

37 The Bay Watershed. Animals by the numbers What is changing? Beef Dairy 37

38 The Bay Watershed. Turkey Broiler 38

39 The Bay Watershed. Turkey Goats Sheep Horses 39

40 The Bay Watershed Big Question how to clean up? Stop urban development and growth? Stop Agriculture? 40 Source: Chesapeake Bay Program

41 Should we be concerned about availability of Phosphorus? Phosphateforum.org Cordell et al Demand for P predicted to peak in

42 Sustainable P Utilization. Recover and Reuse P from all feasible sources: municipal wastewater treatment plants, animal manures, and industrial waste water

43 Biogas + Greenhouse Veggie Production (Source: Cheng, NC State Univ.) Nitrification Biofilters

44 Thank You Questions? Contact: Jactone Arogo Ogejo Biological Systems Engineering Virginia Tech (540) Source: Moffatt B., AgStar Conference 2007

Welcome to Manure Du Jour

Welcome to Manure Du Jour Serving Pennsylvania s Best Practices for Animal Ag-, Air- and Water Quality Protection Small and Medium Scale Anaerobic Digesters for Temperate Regions Dr. Bob Graves, Professor