Fact Sheet #24:Technology Options to Comply with Land Application Rules By Alan Sutton, Purdue University, and Frank Humenik, North Carolina State University
EPA CAFO Regulations • Require all large CAFO operators to properly apply manure, litter, and wastewater to land under the control of the CAFO • Must apply based upon a nutrient management plan (NMP) • Generally means application restricted to meet nutrient needs of crops • Sufficient land may not be available for manure and wastewater application at agronomic rates.
Possible Solutions • Technology options can treat and process manure and wastewater to reduce • Volume. • Concentration of nutrients. • Organic loading. • Result: Reduce the land needed for the CAFO operator to comply with the new CAFO rule.
Technologies Available • Animal ration modification • Manure treatment • Physical treatment • Chemical treatment • Biological treatment
Animal Ration Modification • Nutrients in animal diets affect the amount of nutrients excreted in manure. • Animal diet can increase the percentage of nutrient retention in the animal and animal products and reduce nutrient excretion. • Example: Reducing crude protein and adding synthetic amino acids (AAs) in swine diets can reduce nitrogen (N) excretion up to 50%.
Digestive Processes • Feed intake to provide nutrients • Maintenance (endogenous losses) • Production (intended purposes) • Increasing digestibility (availability) of nutrients will reduce excretion • Enzymes • Genetically modified feed ingredients • Feed processing technologies
Nutrient Digested Nutrient Consumed Nutrient Absorbed Nutrient Excreted Nutrient Retained in Body Tissues
Amount Excreted • Amount of dietary nutrient consumed • Efficiency of nutrient utilization and retention • Amount of endogenous losses
Manure Treatment • Designed to reduce constituents in solids and liquids that must be managed on farm • Byproduct recovery process may transform wastes into value-added products that can be marketed off the farm.
Reasons to Treat Manure • Reduce odor and ammonia volatilization • Remove solids for easier and less cost liquid treatment • Convert manure solids to value-added products such as methane, compost, or animal feed • Reduce liquid nutrient levels to reduce amount of land needed for application
Solids-Liquid Separation Mechanical methods: • Gravity settling tanks or channels • Sloping screen • Vibrating screen • Screw press/roller press/belt press • Underslat belt systems • Underslat scraper systems • Centrifugal
Mechanical Solids-Liquid Separation • Gravity tanks and mechanical separation systems commonly remove 15% to 25% solids, N, and phosphorus (P). • Separated solids are more stable (less odor) than liquid manure during storage and land application.
Mechanical Solids-Liquid Separation (cont'd) • Separated solids can be further treated by composting with a turner or manure loader. • Mechanical system requires maintenance.
Belt System Performance Waste Characteristics Urine: N – 77% P – 4% K – 41% Fecal Matter: N – 23% P – 96% K – 59%
Michigan State Trough and Scraper System Six-State Consortium
Japanese Scraper System Showing Scraped Feces Six-State Consortium
Temperature ºF Psychrophilic (maturation) Composting Principles (cont'd) Substrate depletion Temperature plateau Heating Thermophilic (conversion) 105 Mesophilic (degradation) 50 Time
Composting Principles (cont'd) Efficient composting requires • A balanced source of energy and nutrients • Typically with a C:N ratio between 20:1and 40:1 • Sufficient moisture • Typically between 40% and 60% • Sufficient oxygen • Typically 5% or greater • A pH range between 6 and 8
Compost Product • After composting, reduced solids volume by 40% to 50% • Nitrogen is incorporated into bacterial cells. • Odors are reduced to a humus-like aroma. • Concentrated nutrients in a stable form • Easily stored and transported to application areas • Can add inorganic fertilizer to balance nutrients. • Pelleting the mixture for commercial use is feasible.
Plant nurseries Lawn care Golf courses Horticulture uses Mushroom production Other soil amendment uses outside of the watershed of origin Commercial Uses of Compost
Flocculants • Chemical flocculants–aluminum sulfate (alum), ferric chloride, magnesium chloride • Polymers such as polyacrylamides also work well. • Flocculants can remove up to 75% of organic solids and very high levels of P. • Can be expensive
Constructed Wetlands (cont'd) • Polish runoff from open lots or animal facilities. • Treat animal wastewater after solids removal. • Reduce P removal over time.
Constructed Wetlands (cont'd) • High N mass removal of 5,870 kg/ha/yr for 270 days/yr at N loading of 25 kg/ha/day • Only 10%-15% ammonia volatilization during summer at high N loading rate of 25kg/ha/day
Constructed Wetlands (cont'd) • Nitrification of wetland influent results in about a fivefold increase in N removal.
Sequential Batch Reactor (SBR) Large SBR
SBR (cont'd) • In-vessel complete system that can provide soluble nutrient removal and solids settling • Cyclic aerobic-anaerobic treatment can result in up to 95% COD, 98% NH3, and 91% total N removal. • Concentrate minerals and sludge (97% P)
Sequencing Batch Reactor • Stages include: • Anoxic - fill • Aerobic - react • Anaerobic - react • Settling (quiescent) - settle • Decant - draw off clarified liquid after settling • Sludge removal • Idle (sometimes for adjustment)
Summary • Land application areas on some AFOs may not be sufficient to meet the requirements of the CAFO rule. • Dietary strategies can greatly reduce the amount of nutrients excreted in manure. • Potential value-added products can be produced for off-farm transport and utilization.
Summary (cont'd) • Technology options can reduce nutrient concentra-tions to decrease the land base needed for wastewater or manure application. • As CAFOs grow in size, these technologies may prove economically attractive versus securing more land for manure and wastewater application.
Aerobic–microbial degradation with oxygen Anaerobic–microbial degradation without oxygen CAFO–concentrated animal feeding operation Composting–aerobic treatment of solids into a humus product Definition of Terms
Definition of Terms (cont'd) Flocculation–compounds that will precipitate nutrients Sequencing batch reactor–in-vessel system treating waste aerobically and anaerobically
Authors Alan Sutton, animal nutrition and waste manage-ment specialist, Purdue University, can be reach-ed at email@example.com, and Frank Humenik, Waste Management Specialist, North Carolina State University, can be reached at firstname.lastname@example.org.
Reviewers The authors wish to thank John Classen, North Carolina State University; Mark Risse, Universityof Georgia; and John Sweeten, Texas A & M University, for their review of this fact sheet.
For More Information Environmental Regulations Related ResourcesEPA CAFO Phone Line–202-564-0766 http://www.epa.gov/npdes/caforule/–To obtain copy of regulations http://www.epa.gov/npdes/afo/statecontacts/–To obtain state environmental agency contacts http://www.epa.gov/agriculture/animals.html/–To obtain compliance assistance information from EPA http://cfpub.epa.gov/npdes/contacts.cfm?program_id=7&type=REGION/–To obtain EPA Region Animal Feeding Operation contacts
For More Information (cont'd) Land-Grant University Resources The local contact for your land-grant university Cooperative Extension program is listed in the phone book under "Cooperative Extension" or "(county name) County Cooperative Extension." http://www.reeusda.gov/1700/statepartners/usa.htm/–To obtain state Cooperative Extension contacts http://www.lpes/–To view the Livestock and Poultry Environ-mental Stewardship (LPES) curriculum resources
For More Information (cont'd) USDA Farm Bill Resources To obtain more information about the Farm Bill 2002, see the USDA-NRCS website at the following URL: http://www.nrcs.usda.gov/programs/farmbill/2002/. You can also contact your local USDA Service Center, listed in the phone book under "U.S. Department of Agriculture," or your local conservation district.
Funding This material is based upon work supported by the Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture; the U.S. Environmental Protection Agency, the National Agriculture Assistance Center; and the University of Nebraska Cooperative Extension, University of Nebraska-Lincoln, under Cooperative Agreement Number 97-EXCA-3-0642.