Mitigating Odor on Farms Using Modern Technology Midwest Manure Summit 2009 Frank Mitloehner, PhD Assoc. Professor & Specialist Department of Animal Science University of California, Davis North SJV Dairy Locations South
National Ambient Air Quality Standards (NAAQS) Primary standards to protect public health National monitoring network Original implication A point measurement represents broad geographical area. Public exposure is frequent or extended. NAAQS No NAAQS for odor PM 10 standards 150 µg/m 3 24-hour average 50 µg/m 3 annual average PM 2.5 standards 65 µg/m 3 24-hour average 15 µg/m 3 annual average Nuisance Condition Any condition that inhibits the reasonable use or enjoyment of property
The FIDO Factors in Odor Assessment Frequency (events/yr) Intensity (dilutions to threshold) Duration (hrs/event) Offensiveness (subjective) Sources of Odor Silage leachate Open lots Manure stockpiles Disposal pits Land application areas Runoff holding ponds Anaerobic lagoons Mortalities
Odor Management Techniques Managing manure moisture Corral design Corral maintenance Manure harvesting techniques Manure and mortality treatment Managing Solid Manure for Odor Control Collect manure frequently. Store under roof (long axis E-W). Divert rainfall and runoff. Provide adequate storage area. Mix wet material quickly with drier material. Compost. Limit exposure to the elements. Perforate or cleave thoracic cavity and cover carcass with 1-2 inches of dry, organic material. Recall that burial is generally no longer acceptable. Compost. Managing Mortalities for Odor Control
Managing Liquid Manure for Odor Control Stagnant water creates anaerobic conditions. Use adequate flush volumes (80-100 gpm/ft). Reduce VS loading rate to lagoons (e.g., solids separation). Inject or incorporate into soil. Irrigate at appropriate times. Dilute lagoons with fresh water. Anaerobic Lagoons Wind Odors/ VOC? organics Anaerobic bacteria CO 2 NH 3 CH 4 H2 S Sludge Zhang, 2001, modified Gases and odors N Nitrogen S Sulfur C Carbon NH 3 N 2 O NO H 2 S CH 4 CO 2 VOC Ammonia Nitrous oxide Nitric oxide Hydrogen sulfide Methane Carbon dioxide Volatile organic compound Waste only Animals and Waste
Ammonia Ammonia forms from urea in urine Cattle cause 48% of ammonia emissions (EPA, 2002) Motor Domestic Veh Point Srcs5% 3% 11% Soil 14% Cattle 48% Fertilizer 3% Poultry 16% Volatile Organic Compounds (VOC) VOCs are precursor in the formation of ozone (smog) smog forming gases VOC = approx 700 individual reactive gases CA dairies are listed as the largest VOC source Animal Manure Crop Residue Food Processing By-Product
Biomass to Energy Food farming and processing already produce excess cellulosic biomass that could become biofuels. Bio-fuels can be made from manure, leftover rice straw, wheat straw, orchard tree prunings, nutshells, fruit pits, and wine-grape skins and seeds. Energy crops can be grown-- high-yield grasses such as miscanthus and switchgrass; oilseed crops such as canola, safflower and sunflower; and sugar crops such as beets and sweet sorghum. Green Waste Food Leftovers Animal Manure Food Processing By-Product
Biomass to Energy Other biomass could be diverted from municipal waste -- materials such as paper and cardboard that are unsuitable for recycling; tree trimmings; and restaurant and residential garbage. Organics Mixed Solid Waste Inorganics UC Davis Biogas Energy Project Ruihong Zhang Biological and Agricultural Engineering UC Davis
UC Davis Biogas Energy Plant Digester capacity 3-8 tons per day Digestion temperature 135 F Expected biogas yield 11,000-22,900 ft 3 /day Electricity output 600-1200 kwh/day Sponsors: California Energy Commission California Integrated Waste Management University of California, Davis Onsite Power Systems and other companies UC Davis Biogas Energy Plant
UC Davis Campus Organic Residuals 31 tons per day Waste Source Weight (tons/day) Moisture (%) Biogas Energy (therm/day) Electrical Energy (kwe)* ARS Bedding 5.4 20% 361 141 Green Waste 0.7 70% 16 6 Food Waste 4.1 80% 108 42 VMTH Bedding 4.7 20% 313 123 Dairy Manure 16.5 85% 57 22 Total 31.3 62% 856 334 Kwe based on 32% HHV thermal efficiency generator Not including manure from swine farm and beef feedlot, and sheep barns Current Solid Waste Management Practices on Campus University Landfill 12,750 tons - 63,750 cu yds ARS Bedding, Green and Food Wastes Land Application Dairy Manure Compost (Student Farm), Alfalfa fields Offsite Composting VMTH Bedding (Vacaville) Food waste
Biogas 98,900 ft 3 /day (10-15% hydrogen, 45-50% methane) Electricity (7920 kwh/day) + Heat (200 therms/day) Or Compressed Natural Gas (48,000 ft3/day) Liquid Effluent 2800 gal/day Organic Residuals 31 tons/day Compost 11 tons/day Estimated Capital Cost for UC Davis Biogas Energy Facility at 31 ton per day capacity 2.9 Annual Expenses & Revenue for a 31 tpd Biogas Energy Plant with 20 $/ton Waste Tipping Fee 51% 9%
Waste to Energy - A village off the grid -
Frank Mitloehner, PhD; Air Quality CE Specialist Animal Science Department; University of California, Davis (530) 752-3936; fmmitloehner@ucdavis.edu