MINIMIZING ODOR AND COST OF COMPOSTING PROCESSES FOR ORGANIC WASTES

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
403	0199	2020	100%

Progress 05/15/00 to 09/30/05

Outputs
Project has studied handling of poultry, swine and dairy manure using composting. Documented were advantages of belt system with composting for caged layer manure, use of high rise hog building, and dry matter and nutrient loss when composting dairy manure (Michel, 2005). Laboratory and field studies determined the effects of continuous and intermittent aeration on odor control and NH3 loss (Willet 2005). Project has developed computer models for evaluating effects of aeration strategies and temperature control on efficiencies of composting process. In 2005 composting sand laden dairy manure with waste paper and yard trimmings and utilizing compost made from horse manure/cardboard bedding studied. Numerical modeling of the effects of aeration strategies (recirculation and reversed-direction airflow) published by Ekinci, 2005a. The thermodynamics, kinetics, and energy use of composting systems with air recirculation were determined by simulating the composting for paper mill sludge and biosolids (Ekinci 2005b). Results showed that at low airflows and high recirculation ratio, heat removal by the exhaust gas was insufficient to maintain set point temperatures with the result process temperatures increased and limited the reaction rate. Consequently, dry matter loss decreased indicating prolonged processing time to reach stability. Types of feedstock, magnitude of airflow and recirculation ratio, all affected energy use of system. Keener (2005a) studied the effects of intermittent aeration on the composting operation. A multi-parameter kinetic model in conjunction with heat and mass balance equations were used to predict and optimize the performance of composting systems. Equations evaluating airflow and on/off fan cycle times on composting temperature, oxygen and moisture were developed. Kinetic data from pilot scale experiments using three different feedstocks: municipal solid waste, biosolids/woodchips, and grass/leaves/brush were used in the derived equations to evaluate the composting systems operation. A rain simulator was used to study (Keener, 2000b) amounts of runoff constituents such as total suspended solids, total dissolved solids (TDS), ammonia nitrogen (NH3-N), phosphorous and potassium (K) from dairy cow manure/sawdust (C/N ratio of 36, N = 1.3%) composting in windrows. Two years of research were reported. The 1st year test (100, 25 and 5 year storm events based on 2 in/hr) included testing a fleece compost cover. Results showed chemical concentrations in runoff were higher for compost with a higher moisture content, 70% vs. 64%. Use of a cover lowered concentrations of pollutants. Year 2 studies composting dairy manure/sawdust used a storm event of 2 in/hr for 1.5 hrs (75 year storm) and 3 ages of compost, 0, 16.5 and 30 days (3 replicates). Results showed water runoff increased (went from 20% to 60% of rainfall applied) while nutrients in runoff decreased with compost age. Loss factors for %NH3-N, P and K from composts were evaluated for three time periods. Results can be applied to the design of control structures for treating runoff from compost pads.

Impacts
a.Reduced emissions from caged layer egg production facilities. Studies documented reduced emissions of the caged layer belt/composting system over conventional deep pit system. b.Reduced cost of composting animal manures. Studies have documented effects of controllable factors on kinetics of process,enabling engineers to reduce facility and operating cost of compost systems. Showed low airflow,regardless of composting system configuration,was main factor to minimize energy usage,yet achieve a specific rate of decomposition. Developed Excel computer simulation model of composting process enable farmers to optimize design and management of facilities,to minimize cost of treatment and enable better management of composting process c.Reduced cost of manure management,transporting nutrients offsite. Studies on dry matter and water loss during composting allow economic analysis to be made on process cost and cost of transporting nutrients offsite. d.Reduced odor generation during composting of animal manure. Odor studies have documented collecting and composting fresh manure has potential to reduce odor at composting site. Aeration during composting resulted in destruction of odorous compounds (95-100%) by day eight. Biofilters are only needed for short period of times. Composting dairy manure/amendment mix with C/N above 40 reduces N losses significantly. e.Reduced cost to design runoff control structures for compost pad. Studied evaluated loss factors for %NH3-N,P and K from composts that can be applied to the design of control structures for treating runoff from compost pads.

Publications

Ekinci, K., H.M. Keener, D.L. Elwell, F.C. Michel Jr. 2005a. Effects of aeration strategies on the composting process: Part II. Numerical modeling and simulation. Transactions of ASAE. 48(3):1203-1215
Ekinci, K., H.M.Keener, D. Akbolat. 2005b. Effects of feedstock, airflow rate, and recirculation ratio on the performance of composting systems with air recirculation. Bioresource Technology xxx( ):xxx-xxx
Keener, H.M., K. Ekinci, D.L. Elwell, F.C. Michel, Jr. 2005a. Composting process optimization - using On/Off control. Compost Science and Utilization. 13(4):288-299
Keener, H.M., T.F. Wilkinson, F.C. Michel Jr. and L.C. Brown. 2005b. Evaluation of leaching from composting windrows using a rainfall simulator. 2005 Animal Waste Management Symposium. 10/5-7. Sheration Imperial Hotel and Conference Center, Research Triangle Park, North Carolina.
Michel Jr., F.C., H.M. Keener, J.Rigot, T. Wilkinson and J. Pecchia. 2005. Effects of Straw, Sawdust and Sand Bedding on Dairy Manure Composting. Symposium on the State of Science of Animal Manure and Waste Management. 1/5-7. Marriott River Center, San Antonio, TX. Published on CD (search at: http://www.cals.ncsu.edu/waste_mgt/natlcenter/sanantonio/proceedings. htm)
Tiquia, S.M., J.M. Ichida, H.M. Keener, D.L. Elwell, E.H. Burtt and F.C. Michel. 2005. Bacterial community profiles on feathers during composting as determined by terminal restriction fragment length polymorphism analysis of 16S rDNA genes. Applied Microbiology and Biotechnology. 67 (3):412-419
Willet, L.B., D.L. Elwell, H.M. Keener, D.C. Borger. 2005. Volatile emissions from composting dairy manures as indicators of bioprocesses and objectionable odors. Final Report. May 15. APWMC. NCSU.

Progress 01/01/04 to 12/31/04

Outputs
Composting research in 2004 focused on aeration strategies, temperature control, odor and composting horse manure/cardboard bedding. Previous studies for aeration strategies (one-directional airflow, one-directional airflow with recirculation, reversed-direction airflow, and reversed-direction airflow with recirculation) published by Ekinci et al., 2004a. Studies on location of thermocouple(s) to control aeration fans to maximize rate of decomposition for composting systems were done. Results were developed by simulating system performance using a two-dimensional finite difference numerical model of the composting reactor and a two-component first-order kinetic model of decomposition. Results showed that thermocouple locations significantly affected dry matter loss and energy usage of the system and that dry matter loss is higher in the middle layers than outer layers when the thermocouple sensor is placed in the middle layers. Additionally, results showed controlling the temperature at 60 C requires less energy than controlling the temperature at 50 C (Ekinci et al., 2004b,c). Studies on composting horse manure and a commercial cardboard bedding, based on full scale, pilot, and simulation experiments done. Chemical, physical, and kinetic data on composting materials were summarized. Results showed a compost mix of 20.5 kg horse manure and 4.3 kg bedding had desirable chemical and physical properties for composting. At the start of the composting process moisture content was 56% and C/N ratio was 33. On day 90, moisture content was 48% and C/N ratio 17.3. From the full-scale studies with non-aerated windrows the compost mix was shown to compost without odor. Sizing of composting system for various horse stable sizes were done using a computer simulation program that incorporated the pilot scale kinetic data. Composting pad for a 1000 head horse stable found to be 0.33 ha based on a composting time of 180 days, 28 days windrow composting and 152 days curing. Compost generated by the facility would be 5.0 t/day at 44% moisture (Keener et al., 2004). Two growth trials were done with composted horse manure/cardboard bedding (hm/cb) as an amendment in soilless horticultural mixes. A cucumber bioassay recommended by the US Composting Council was followed. Results determined seventy days of composting in windrows, and a hm/cb compost amendment rate of 20 percent (i. e. a potting mix containing 20 % compost, 50 % peat and 30 % Perlite,v/v) was most suitable for production of cucumber plants if a fertilization rate of 200 ppm N was utilized. Previous studies on odor control when composting animal manures were analyzed using a mixed model ANOVA. Anaerobic aging greatly enhanced the concentration of volatile organic compounds (VOC)s in manures. Composts that were maintained aerobically had rapid declines in concentrations of VOCs with 98 to 100% eliminated within a week. Excessive aeration of composts did not enhance VOC destruction and increased VOC and ammonia emissions. Generally emissions of VOCs from closed composting vessels represented less than 0.25% of the VOC odorants in the initial compost mixes (Elwell et al., 2004).

Impacts
a. Reduced cost of composting animal manures. Studies documented effects of controllable factors on kinetics of process, enabling engineers to reduce facility and operating cost of compost systems. b. Reduced odor generation during composting of animal manure. Odor studies have documented collecting and composting fresh manure has potential to reduce odor at composting site. Aeration during composting resulted in destruction of odorous compounds (95-100%) by day eight. c. Marketing of waste cardboard as horse bedding. Manure generated from use of chipped cardboard for bedding horses compost well and generates little odor. Compost product can be used in soilless horticultural medium.

Publications

Ekinci, K., H. M. Keener, D. L. Elwell, F. C. Michel, Jr . 2004. Effects of aeration strategies on the composting process. Part I - Experimental studies. Transactions of ASAE. 47(5): 1697-1708.
Ekinci, K., H. M. Keener; F. C. Michel, Jr.; D. L. Elwell. 2004. Modeling composting rate as a function of temperature and initial moisture content. Compost Science and Utilization. 12(4):356-364.
Ekinci, K., H.M. Keener, Akbolat D. 2004. Effect of Thermocouple Location on the Optimum Composting Rate Biosystems Engineering 89(3):345-353.
Elwell, D.L., D.C. Borger, D.V. Blaho, J.V. Fahrni, H.M. Keener and L.B. Willett. 2004. Changes in concentrations of malodorous compounds during controlled aeration composting. Compost Science and Utilization. 12(2):102-107
Keener, H.M. 2004. Opportunities and challenges in composting organic waste. pp. 27-46. Proceedings International Symposium on Organics Recycling (ISOR). October 5-7. Akita, Japan.
Keener, H.M., D.L. Elwell, K. Winbush, R. James. 2004. Evaluation of approaches for composting horse manure and commercial cardboard bedding. ASAE Paper 044068. Presented at 2004 ASAE/CSAE Annual International Meeting. 8/1-4. Fairmont Chateau Laurier, The Westin, Government Centre, Ottawa, Ontario, Canada. Published on CD (search at asae.frymulti.com)

Progress 01/01/03 to 12/31/03

Outputs
Research in 2003 focused on handling manures from swine and dairy. Three swine total confinement systems where analyzed and compared based on production factors, with emphasis on manure handling and odor reduction technologies. Systems compared were conventional deep-pit confinement houses, HIGH-RISE(TM) hog building(HRHB), and hoop house. The hoop system gave the highest return to management (Rausch and Keener, 2003). Studies of manure nutrient translocation through a commercial scale HRHB and an associated commercial composting system were done. Results showed the nitrogen, phosphorous and potassium losses from the HRHB were 43, 10 and 47% of the initial nutrient amounts, respectively. Windrow composting led to 15% N, 8% K, and negligible P of loss of initial manure/amendment mixture throughout a 100 days composting process (Sun, 2003). Results of full scale windrow composting of dairy manure were reported (Michel et al., 2003) for compost made from free stall dairy manure (83% moisture) amended with either hardwood sawdust or straw and composted for 110-155 days in turned windrows. Initial C:N ratios of the windrows ranged from 25:1 to 50:1. Results showed all sawdust-amended composts self-heated to temperatures >55 degreeC within 10 days, maintained these levels for more than 60 days and met EPA and USDA pathogen reduction guidelines. However, only two of the four straw amended windrows reached 55 degreeC and none met the guidelines. Both types of compost were stable after 100 days (CO2 evolution rates <0.5 mg CO2-C/g VS/dy) and had extensive manure volume and weight reductions (50 to 80%). Total manure N lost during composting ranged from 7%-38%. Results showed initial C:N ratio greater than 40 during dairy manure composting minimized nitrogen loss. Governing equations for design and operation of composting systems were incorporated into an Excel spreadsheets. The spreadsheet consisted of four sections: a) formulation of compost mix to meet C/N and moisture requirements; b) design of pad showing areas for composting and curing including pile sizes and numbers; c) evaluation of process for dry matter and moisture losses, airflow and fan size requirements; and d) a summary sections giving input and output masses and volumes, and fan energy cost. Simulation optimization studies, done on dairy manure/sawdust mixes using 2001 data from pilot scale studies, showed using small amounts of recycled compost and composting manure in two stages could reduced cost significantly (Keener et al., 2003a,c). Initiated pilot scale composting studies on sand laden dairy manure (DM) with horse manure/bedding or with sawdust. Results from previous odor studies on composting dairy manure/sawdust mixtures using intermittent and continuous aeration were published (Elwell et al., 2003a,b). Continuous aeration, as opposed to intermittent, more than doubled (115 vs 55g) the emissions of NH3-N and increased the emissions of VFAs in condensate four fold. Previous studies on poultry manure management published (Keener et al., 2002 and Keener and Elwell, 2003). Pilot and full scale windrow studies were started on composting horse manure and chipped cardboard bedding

Impacts
c. Reduced cost of composting animal manures. Studies have documented effects of controllable factors on kinetics of process, enabling engineers to reduce facility and operating cost of compost systems. Showed low airflow, regardless of composting system configuration, was main factor to minimize energy usage, yet achieve a specific rate of decomposition. Developed Excel computer simulation models of composting process enable farmers to optimize design and management of facilities, to minimize cost of treatment and enable better management of composting process. d. Reduced cost of manure management, transporting nutrients offsite. Studies on dry matter and water loss during composting allow economic analysis to be made on process cost and cost of transporting nutrients offsite. e. Reduced odor generation during composting of animal manure. Odor studies have documented odor changes in manure between day 1 and day 10. Result suggests collecting and composting fresh manure has potential to reduce odor at composting site. Aeration during composting resulted in destruction of odorous compounds (95-100%) by day eight. Biofilters are only needed for short period of times. Composting dairy manure/amendment mix with C/N above 40 reduces N losses significantly. f. Marketing of waste cardboard as horse bedding. Manure generated from use of chipped cardboard for bedding horses compost well and generates little odor.

Publications

Keener, H.M., R. Maghirang and B. Auvermann (eds). 2003. Air Pollution from Agricultural Operations-III: Proceedings Third International Conference on Air Pollution from Agricultural Operations. 10/12-15. Research Triangle Park, NC. 353 p. American Society of Agricultural Engineers, St. Joseph, MI.
Elwell, D.L., D.C. Borger, H.M. Keener and L.B. Willet. 2003a. Reduction of volatile odorous chemicals in composting of dairy manure. ASAE Paper 034049. Presented at 2003 ASAE Annual International Meeting. 7/27-30. Riveria Hotel and Convention Centr, Las Vegas, NV. Published on CD (search at asae.frymulti.com)
Elwell, D.L., D.C. Borger, D.V. Blaho, J.V. Fahrni, H.M. Keener and L.B. Willett. 2003b. Changes in concentrations of malodorous compounds from fresh and aged manure during controlled aeration composting. Compost Science and Utilization. (Approved for Publication)
Michel Jr., F.C., J.A. Pecchia, J. Rigot, H.M. Keener. 2003. Mass and nutrient losses during composting of dairy manure with sawdust versus straw amendment. Compost Science and Utilization. (Approved for Publication)
Keener, H.M., and D.L. Elwell. 2003. Caged layer manure management on flies, water and nitrogen levels - case studies of current technologies. ASAE Paper 034128. Presented at 2003 ASAE Annual International Meeting. 7/27-30. Riveria Hotel and Convention Centr, Las Vegas, NV. Published on CD (search at asae.frymulti.com)
Rausch, J.N. and H.M. Keener. 2003. More than pig performance: The case of three feeder pig systems. pp. 83-93. In: Swine Housing II: Proceedings of the 2nd International Conference. 10/12-15. Research Triangle Park, NC. American Society of Agricultural Engineers, St. Joseph, MI.
Sun, H., H.M. Keener, T.A. Menke and F.C. Michel, Jr. 2003 Nutrient balance study of the High-RiseTM hog system and associated windrow-composting process. ASAE Paper 032254. Presented at 2003 ASAE Annual International Meeting. 7/27-30. Riveria Hotel and Convention Centr, Las Vegas, NV. Published on CD (search at asae.frymulti.com)
Keener, H.M. J.A. Pecchia, G.L. Reid, F.C. Michel Jr, D.L. Elwell. 2003b. Optimizing design and operation of dairy manure composting systems - using pilot and full scale kinetic studies. pp. 310-324. In: Animal Agricultural and Food Processing Waste IX: Proceedings The Ninth International Symposium on Animal, Agricultural and Food Processing Wastes. 10/12-15. Research Triangle Park, NC. American Society of Agricultural Engineers, St. Joseph, MI.
Keener, H.M., F.C. Michel, Jr., D.L. Elwell. 2003a. Spreadsheet computer models for design and management of compost systems. Proceedings of the 2003 Annual International Meeting of the Institute of Biological Engineering. 1/17-19. Athens, GA. Published on CD.

Progress 01/01/02 to 12/31/02

Outputs
Research in 2002 focused on manures from poultry, swine and dairy operations with emphasis on reducing flies, odors, and composting to produce a value added product. An 18 week study was conducted to determine effects of turning poultry manure in deep pit pullet and layer houses. Study focused on manure temperatures, fly control, and ammonia concentrations. Results showed turning of poultry manure in a high rise deep pit assisted in breaking the fly life cycle, reduced the number of chemical applications for fly control, increased drying rate of the manure, and worked as a management practice for fly control only in the context of a multi-facet approach (Keener and Elwell, 2002). Composting studies for dairy manure/sawdust and dairy manure/straw were done in full scale windrows and in pilot scale (200L) vessels. The outdoor full scale windrow studies used both solid and liquid dairy manure waste streams. Studies included: (1)TW, turned windrows/ natural convection/ no cover, (2)TWA, turned windrows/ controlled aeration/ no covers and (3)TWC, turned windrows/ natural convection/ covered. Volume, weight, dry matter, moisture and nitrogen losses during composting were presented as functions of composting time. Results for free stall dairy manure mixed with sawdust or straw using the TW method showed weight and volume losses of over 80%. Normalized to the original manure weights and volumes, reductions from composting were 77% w/w and 42% v/v with the sawdust amendment and 76% w/w and 57%v/v with the straw. TWA studies using oxygen levels to set aeration patterns showed aeration increased total weight, water and nitrogen losses. Results for TWC studies showed covering the windrow with a fleece blanket reduced dry matter and N losses during composting. Over a 77-day composting period, %C loss was 54% versus 38 % while N loss was 18% to 4% for uncovered vs. covered, respectively. Compost moisture was lower with covers due to covers shedding rainfall. Pilot scale studies investigated malodorous compounds in, and emitted from fresh and aged (12 days) dairy manure using continuous and intermittent aeration. Dairy manure was mixed with sawdust (3:1 w/w, C/N =25-35) and composted for either 7 or 14 days in four separate studies. Results showed high destruction and/or rapid removal of C2 to C5 volatile fatty acids, phenolics, indolics, skatole, ammonia, hydrogen sulfide, dimethyl sulfide, and methyl- plus ethyl mercaptans. This suggests odor control only needed early in the process. Earlier study on ammonia emissions from a 1.6 million caged layer poultry facility using two types of manure management, belt/composting (no amendment) and deep pit, were published (Keener et al, 2002). NH3 emissions for belt/composting were 1/2 of conventional cage layer systems and the dry product from belt/composting was economical to market as a fertilizer up to a 50 miles from the source. Previous study on optimizing throughput capacity of composting facilities based on decomposition rate versus mixing ratio published (Ekinci et al., 2002). Previous study on composting hog manure/sawdust mixtures using intermittent and continuous aeration published (Elwell et al, 2002)

Impacts
a. Reduced emissions from caged layer egg production facilities. Studies documented reduced emissions of the caged layer belt/composting system over conventional deep pit system. b. Reduced fly outbreaks/nuisance problems with deep pit caged layer facilities. Evaluated effect of windrowing (composting) poultry manure in deep pit houses on fly control and ammonia levels and documented how it can be used as part of a total fly/manure management program. c. Reduced cost of composting animal manures. Documentation on effects of controllable factors on kinetics of process enable engineers to reduce facility and operating cost of compost systems. Showed low airflow, regardless of composting system configuration, was main factor to minimize energy usage, yet achieve a specific rate of decomposition. Studies on optimization enable better management of composting process. d. Reduced cost of manure management, transporting nutrients offsite. Studies on dry matter and water loss during composting allow economics analysis to be made on process cost and cost of transporting nutrients offsite. e. Reduced odor generation during composting of animal manure. Odor studies have documented odor changes in manure between day 1 and day 10. Result suggests collecting and composting fresh manure has potential to reduce odor at composting site. Aeration during composting resulted in destruction of odorous compounds (95-100%) by day eight. Biofilters are only needed for short period of times.

Publications

Keener, H.M., S.S. Foster, S.J. Moeller, D.L. Elwell. 2002. Dealing with dead livestock. Resource. 9(8):9-10
Pecchia, J.A., H.M.Keener, and F.C. Michel Jr. 2002. (abstract) Dairy manure composting: amendment effects on compost mass balance. pp. 43. In: Abstracts of Presentations and Posters at Proceedings 2002 International Symposium on Composting and Compost Utilization. May 6-8. Columbus, Ohio.
Willett, L. B., D. C. Borger, D. L. Elwell, and H. M. Keener. 2002. Initial concentrations and disappearance of selected malodorous compounds from fresh and aged dairy manures. Toxicologist 66(1-S): 194.
Ekinci, K., H.M. Keener and D.L. Elwell. 2002 Composting short paper fiber with broiler litter and additives. II. Evaluation and optimization of decomposition rate versus mixing ratio. Compost Science & Utilization. 10(1):16-28
Elwell, D.L. J.-H. Hong, and H.M. Keener. 2002 Composting hog manure/sawdust mixtures using intermittent and continuous aeration. Compost Science & Utilization. 10(2):142-149
Elwell, D.L., D.C. Borger, D.V. Blaho, J.V. Fahrni, H.M. Keener and L.B. Willett. 2002. Changes in concentrations of malodorous compounds from fresh and aged manure during controlled aeration composting. Proceedings 2002 International Symposium on Composting and Compost Utilization, Columbus, Ohio. Published on CD -Track 3, May7.
Keener, H.M. and D.L. Elwell. 2002. Dead Animal Composting. Proceedings Nutrient and Sediment Control Innovative Technology Forum. Session II.C. February 12-14. Grantville, PA.
Keener, H.M. and D.L. Elwell. 2002. Evaluation of a frontier turner for manure management and fly control at Buckeye Egg Farms, Croton, Ohio. Report to Buckeye Egg Farm and Ohio Environmental Protection Agency. November 7. OARDC/OSU, Wooster, OH.
Keener H.M., F.C. Michel, Jr., D.L. Elwell. 2002 (abstract) Spreadsheet Computer Models for Decision Making in the Design and Management of Compost Systems. 12th Annual Composting Conference, The Composting Council of Canada. September 18 - 20, 2002. Halifax, Nova Scotia.
Keener, H.M., D.L. Elwell, and D. Grande. 2002. NH3 emissions and N-balances for 1.6 million caged layer facility: manure belt/composting system vs deep pit operation. Transactions of ASAE. 45(6):xxxx-xxxx
Keener, H.M., K Ekinci, D L Elwell, F C Michel, Jr. 2002. Principles Of Composting Process Optimization. Proceedings 2002 International Symposium on Composting and Compost Utilization, Columbus, Ohio. Published on CD - Track 3, May 6.
Ekinci, K., H M Keener, F C Michel, Jr, D L Elwell. 2002 (abstract) Effects of kinetic parameters on the Management of composting cystems with air recirculation. pp. 30. In: Abstracts of Presentations and Posters Proceedings 2002 International Symposium on Composting and Compost Utilization, May 6-8. Columbus, Ohio

Progress 01/01/01 to 12/31/01

Outputs
Research focused on managing manures from poultry, swine and dairy operations with emphasis on reducing odors, producing a solid waste, and composting to produce a value added product. For caged layer poultry, NH3 emissions from the bird houses and related manure handling systems were evaluated. Results indicated less than 1/2 as much nitrogen was lost from a manure belt collection/composting system (no amendment) than a deep pit manure system for high rise poultry houses. Composted manure produced with the belt composting system had <20% moisture and > 5% N. Broiler liter/paper mill sludge mix with a C/N of 25 was studied both theoretically and experimentally to evaluate decomposition rates. Four aeration strategies of intermittent aeration, air recirculation, reversed direction airflow, and air recirculation with reversed direction airflow systems were investigated. Four different pilot-scale composting systems and a two-dimensional finite difference model of composting were developed. The model was based on a two component first order kinetic model and heat and mass balance equations. Results showed simulation model predicted experimental results, however, boundary condition effects such as condensation significantly affected top layer in all aeration systems. Optimization studies with model showed low airflow, regardless of system, was main factor to minimize energy usage, yet achieve a specific rate of decomposition. Swine manure studies focused on air quality and manure properties for continous and intermittent drying bed operation for the High-RiseTM Hog Building during winter operation. Results showed NH3 levels were <22 ppm in occupied (hogs') space throughout test periods, but exceeded 50 ppm in lower story during winter periods of low ventilation. Mixing manure with drying bed material during operation identified as an important practice to improve manure management for HRHB. Work on dairy manure investigated concentrations of malodorous compounds from fresh and aged manure during controlled studies using continuous and intermittent aeration (5/55 minutes on/off). Fresh or 12-day aged manure from lactating cows was mixed with sawdust (3:1 w/w, C/N = 25-35). Six replicated studies were done for each of the four treatments. Temperature, airflow, O2 consumption, CO2 production, NH3 emission, and volatile fatty acids (in mix and emissions) were evaluated along with compost mix moisture, C, N, ash and pH. By day 17, decomposition rate was low and compost temperatures were near ambient. Results showed aged manure had increases for C2-C5 volatile organics (43-900%) and had formed skatole. This result suggests collecting and composting fresh manure has potential to reduce odor at composting site. Both aeration methods resulted in destruction of odorous compounds (95-100%) by day eight. Continuous aeration doubled emissions of ammonia (1.38 g NH3 vs. 0.66 g NH3 per kg initial compost weight) and increased emissions of VFA's in condensate fourfold. Studies continued on effects of bacterial inoculums on keratin degradation in poultry feathers.

Impacts
(N/A)

Publications

Ekinci. K. 2001. (H.M. Keener, advisor). Theoretical and Experimental Studies on the Effects of Aeration Strategies on the Composting Process. Ph.D. Dissertation. The Ohio State University, Columbus, OH.
Elwell, D.L., H.M. Keener and S. Moeller. 2001. Composting animal mortalities, BioCycle 42(5 ):67-68
Elwell, D.L., H.M. Keener, M.C. Wiles, D.C. Borger and L.B. Willett. 2001. Odorous emissions and odor control in composting swine manure/sawdust mixes using continous and intermittent aeration. Transactions of the ASAE. 44(5):1307-1316
Ichida, J.M., L. Krizova, C.A. LeFevre, H.M. Keener, D.L. Elwell, and E.H. Burtt, Jr. 2001. Bacterial inoculum enhances keratin degradation and biofilm formation in poultry compost. J. of Microbiological Methods. 47:199-208
Keener, H.M. 2001. (abstract). Continuous vs. intermittent aeration of drying bed materials straw and sawdust/shavings on N and moisture retention in manure from a High-RiseTM hog facility. pp. ii.50. In: Abstracts of Presentations and Posters at CSAE/SCGR-NABEC Meeting at AIC2001. July 8-11. Guelph, Ontario, Canada.
Keener, H.M., D.L. Elwell, and D. Grande. 2001. Atmospheric NH3 concentrations and N-balances for 1.6 million caged layer facility - manure belt/composting system vs deep pit operation. In: Proceedings International Symposium on Animal Production/Environmental Issues. October 3-5, 2001. Research Triangle Park, NC, USA. Published on CD without page numbers; Session 8, 9p
Keener, H.M., D.L. Elwell K. Ekinci and H.A.J. Hointink. 2001. Composting & value-added utilization of manure from a High-RiseTM swine finishing facility. Compost Science & Utilization. 9(4):312-321
Keener, H.M., D.L. Elwell, T. Menke and R. Stowell. 2001. Design and performance of a high-rise hog facility manure drying bed. Applied Engineering in Agriculture. 17(5):xxxx
Keener, H.M., R.R. Stowell, D.L. Elwell, F.C. Michel and T. Menke. 2001. Operating performance of a High-RiseTM Hog Facility. In: Proceedings International Symposium on Animal Production/Environmental Issues. October 3-5, 2001. Research Triangle Park, NC, USA. Published on CD without page numbers; Session 14. 8p
Michel, F.C. Jr., J. Pecchia, H. Sun and H.M. Keener. 2001. Use of a high-riseTM Building and composting to manage swine manure. October 3-5, 2001. Research Triangle Park, NC, USA. Published on CD without page numbers; Poster Session. 5p
Wiles, M.C.,D.L. Elwell, H.M. Keener, J.C. Amburgey, D.C. Borger and L.B. Willett. 2001. Volatile fatty acid emissions during composting of swine waste amended with sawdust as a measure of odor potential. Compost Science & Utilization 9(1):27-37.

Progress 01/01/00 to 12/31/00

Outputs
Research focused on managing manures from poultry, swine and dairy operations with emphasis on reducing odors, producing a solid waste, and composting to produce a value added product. For poultry, NH3 emissions from caged layers and related manure handling systems were evaluated. Preliminary results indicated less nitrogen was lost from a manure belt collection/composting system (no amendment) than a deep pit manure system for high rise poultry houses. Composted manure was produced with <20% moisture and > 5% N with the belt composting system. Work on swine involved measuring gas levels (NH3, H2S, CO2) and particulates within and emitted from a High-Rise(TM) Hog Building and characterization of the manure. Swine manure and wood shavings (drying bed) were removed from the HRHB facility following two production cycles and composted in aerated pilot-scale vessels for 4 weeks and a mechanically turned windrow for 10 weeks. Total dry matter losses during the pilot-scale studies were 30 and 32.5 % for continuously and intermittently aerated systems, respectively. Moisture, O2, CO2 and NH3 use/losses during the process as well as chemical properties of the initial and composted manure were evaluated. Incorporation of the compost at a 5% amendment rate (v/v) into a standard pine bark container medium significantly (P=0.05) increased growth of two woody plant species. Higher amendment rates were toxic to some plants due to high initial NH4+ concentrations in the medium. The compost significantly (P=0.05) increased growth and suppressed Pythium root rot of poinsettia when incorporated at 10% (v/v) into a standard sphagnum peat mix. The compost can be utilized as a value-added disease-suppressive product in the ornamentals industry. Pilot composting studies on short paper fiber and broiler litter (Ekinci et al., 2000) showed the interactive influence of pH and C/N in ammonia release during composting. Pilot-scale composting studies on swine manure and sawdust (Elwell et al., 2000a,c; Wiles et al., 2000) showed the influence of total air flow (rate of aeration or pattern of aeration application) on ammonia emissions during swine manure composting. Methodologies to trap and analyze individual components of composting manure that are attributed to odors (Wiles et al., 2000, 2001) were developed. Studied were VFAs and phenolics in the compost materials as well as those present in condensed volatiles from the compost gasses. Results from GC analysis and comparison with known standards showed that thermophilic composting can under proper conditions, rapidly catabolize better than 98% of these odorous compounds, thereby reducing their release. Work on unseparated dairy manure (Keener, et. al., 2000a) characterized the principles for moisture removal. Work on characterizing dead animal composting, including development of design equations, completed and training manuals published. Evaluation of bacterial inoculum on keratin degration in poultry feathers studied (Krizova et al., 2000).

Impacts
(N/A)

Publications

Stowell, R.R., H. Keener, D. Elwell, T. Menke and S. Foster. 2000. High-RiseTM hog facility. p. 273-282. In: Proceedings First Int. Conf. on Swine Housing. Oct 9-11, 2000. Des Moines, Iowa. American Society of Agricultural Engineers. St. Joseph, MI.
Wiles, M.C.,D.L. Elwell, L.B. Willett, D.C. Borger and H.M. Keener 2000. Production of odorous, volatile compounds during composting of hog manure amended with sawdust. p. 67-74. In: 2nd International Conf. On Air Pollution from Agricultural Operations. Oct 9-11, 2000. Des Moines, Iowa. American Society of Agricultural Engineers. St. Joseph, MI.
Wiles, M. C., D. L. Elwell, H. M. Keener, J. C. Amburgey, D. C. Borger, and L. B. Willett. 2001. Volatile fatty acid emission during composting of swine waste amended with sawdust as a measure of odor potential. Compost Sci. & Utilization 8: (Accepted for Publication).
Ekinci, K., H.M. Keener and D.L. Elwell. 2000. Composting short paper fiber with broiler litter and additives; Part I, effects of initial pH and carbon/nitrogen ratio on ammonia emission. Compost Science & Utilization 8(2), 160-172.
Elwell, D.L., M.C. Wiles, H.M. Keener and L.B. Willett. 2000a. Odorous emissions from swine manure composting. In: Proceeding Odors and VOC Emissions 2000 Conference. Apr 16-19. Cincinnati, Ohio.
Elwell, D. L., H.M. Keener, T.J. Brown and M.J. Monnin. 2000b. Composting farm animal mortalities in Ohio: legal and practical considerations. p.329-335. In: Proceedings Eight Int. Sym. on Animal, Agr. and Food Processing Waste. Oct 9-11. Des Moines, Iowa. American Society of Agricultural Engineers. St. Joseph, MI.
Elwell, D.L. J.-H. Hong, H.M. Keener and F.C. Michel. 2000c. Ammonia emission from composting hog manure amended with sawdust under continous and intermittent aeration. p. 157-162. In: 2nd International Conf. On Air Pollution from Agr. Operations. Oct 9-11. Des Moines, Iowa. American Society of Agricultural Engineers. St. Joseph, MI.
Keener, H.M., D.L. Elwell, G.L. Reid and F.C. Michel. 2000a. Composting non-separated dairy manure - theoretical limits and practical experience. p. 615-623. In: Proceedings Eight Int. Sym. on Animal, Agr. and Food Processing Waste. Oct 9-11. Des Moines, Iowa. American Society of Agricultural Engineers. St. Joseph, MI.
Keener, H.M., K. Ekinic, D.L. Elwell and F.C. Michel. 2000. Mathematics of Composting- Facility Design and Process Control. p. 164-197. In: P.R. Warman and B.R. Taylor (eds.) Proceedings international composting symposium (ICS'99) - Vol. 1. CBA Press Inc., Nova Scotia, Canada.
Keener, H.M., W.A. Dick and H.A.J. Hointink. 2000. Composting and beneficial utilization of composted by-product materials. Chapter 10. pp. 315-341. In: J.F. Power et al. (eds.) Beneficial uses of agricultural, industrial and municipal by-products. Soil Science Society of America. Madison, Wisconsin.
Keener, H.M. and D.L. Elwell. 2000. Mortality composting principles and operation. p. 1-8. In: Trainers' Manual Ohio's Livestock and Poultry Mortality Composting Manual. OSUE/OARDC, Columbus, Ohio. Keener, H.M., D.L. Elwell and M.J. Monnin. 2000.Mortality composting site selection and design options. p. 9-14. In: Trainers' Manual Ohio's Livestock and Poultry Mortality Composting Manual. OSUE/OARDC, Columbus, Ohio.
Keener, H.M., D.L. Elwell and M.J. Monnin. 2000.Mortality compost facility sizing. p. 15-30. In: Trainers' Manual Ohio's Livestock and Poultry Mortality Composting Manual. OSUE/OARDC, Columbus, Ohio. Keener, H.M., D.L. Elwell, and M.J. Monnin. 2000. Procedures and equations for sizing of structures and windrows for composting animal mortalities. Applied Engineering in Agriculture 16(6):681-692.
Keener, H.M., K. Ekinci, D.L. Elwell and F.C. Michel. 2000. (abstract). Principles of process optimization. p 38. In: Proceedings U.S. Composting Council's 10th Annual Conference. November 12-15. Cleveland, Ohio.
Krizova, L., C.A. LeFevre, E.H. Burtt,Jr., H.M. Keener, and J.M. Ichida. 2000. (abstract) Bacterial inoculum enhances keratin degradation and biofilm formation in poultry compost. p38. In: Proceedings of Microbiology of composting and other biodegradation processes. October 18-20. Innsbruck, Austria.
Stowell, R.R., H.M. Keener, D.L. Elwell and S. Foster. 2000. Gaseous emissions from a High-RiseTM hog facility. Proceeding: Odors and VOC Emissions 2000 Conference. Apr 16-19. Cincinnati, Ohio

Progress 01/01/99 to 12/31/99

Outputs
Three pilot-scale composting test series were conducted using the 208 liter reactor vessels. One of these continued the volatile fatty acid (VFA) capture studies for hog manure sawdust mixes. It confirmed previous ammonia reduction with low airflow results and showed that VFAs are also affected by airflow, with the majority being catabolized before emission. Another of the pilot-scale series characterized composting of dairy manure mixed with horse bedding to determine moisture reduction for extended transport. The third series was conducted in parallel with a full-scale windrow characterization of output material from the drying bed of a High-RiseT hog facility and both parts of this study indicated that this material was suitable for composting. Field research continued on the 4-M farms High-RiseT hog building, a 960 head hog finishing facility in Darke County, Ohio. It features an integrated method of managing the residuals of swine production using a concept in which manure at 90% moisture is partially stabilized and dried in place using an aerated bed of bulking agent (sawdust, woodchips, ground pallets, paper, etc.) beneath a slotted floor. Results on airflow measurements, air quality, and manure mix produced have shown: drying bed air system met design requirements on airflow at the beginning of each cycle and decreased to about 75% of the initial value; The 3/8 inch holes appeared adequate to achieve uniform air distribution across the drying bed and were not subject to plugging; liquids were evaporated from the hog manure and the manure mix at the end of each test (120 day) was 63 % moisture; leachate is minimal from the drying bed and a treatment system is not required; Based on bed temperatures composting was not significant within the drying bed for the conditions tested. Ammonia levels within the basement (normally an unoccupied space) moved inversely up and down with building ventilation rates and exceeded the short-term (ST) exposure limit of 50 ppm in the winter months; Hydrogen sulfide was detectable at <0.3 ppm, far below ST exposure limits, for the first three tests. Suggesting the drying bed was primarily maintained as an aerobic system. CO2 levels in the basement area were well below worker safety limits and below the levels in the upper story; Animal space had mean air quality levels of 4.3 ppm ammonia (never exceeded 20 ppm), 1280 ppm CO2 and non detectable levels of H2S (less than 0.1 ppm). It was concluded the drying bed in the HRHB is functioning as designed and the basement environment is relatively safe.

Impacts
(N/A)

Publications

Elwell, D.L., H.M. Keener and R.R. Stowell. 1999. The high route to managing hog manure. BioCycle 40(10 ):36-38 Ekinci, K., H.M. Keener and D.L. Elwell. 2000. Composting short paper fiber with broiler litter and additives - 1. Effects of initial pH and carbon/nitrogen ratio on ammonia emission. Compost Science

Progress 01/01/98 to 12/31/98

Outputs
Five pilot test series were conducted using four 208 liter reactor vessels for each series. Three series continued 1997 investigations on composting hog manure (HM) solids amended with sawdust (SD) at C/N ratios of 18-24. These studies, focused on intermittent aeration compared to continuous aeration, showed intermittent aeration for HM/SD would give good rates of decomposition while reducing ammonia losses 50%. Exhaust gases from the compost were collected for days 1-21 and are being analyzed using gas chromography for volatile fatty acids. One series was run on intermittent versus continuous aeration for separated dairy solids (no amendment) to evaluate ammonia release and dry matter loss. Results showed 1-3 % of nitrogen and 17-24% dry solids loss. Studies on composting animal mortality - poultry, dairy calves and sows were done to determine the effect of size on composting time. An equation using body weight to the 1/2 power was found to estimate composting time. Results have lead to an 'unification' theory on design and operation of facilities for composting animal mortality. Composting poultry mortality was done in reactor vessels and monitored microbial species over a 12 day period. Field research conducted in a new 960 head hog finishing facility showed ammonia levels within the 'basement area' were within guidelines for operator safety and that no measurable levels of H2S were generated. Building features An Integrated Method of Managing the Residuals of Swine production and is referred to as a 'High-Rise' Hog Building (HRHB) and uses a concept in which manure at 90% moisture is partially stabilized and dried to 30-40% in place using an aerated bed of wood wastes (ground pallets, paper, sawdust, etc.) beneath the hogs' slotted floor. Study of on-farm biofiliter system completed and writing of guidelines has begun. System to handle unseparated dairy manure via composting engineered and field studies planned.

Impacts
(N/A)

Publications

Keener, H.M. and. Elwell, D.L. 1998. Composting animal mortality. Paper presented at 114th Ohio Veterinary Medical Association Annual Meeting, The Midwest Veterinary Conference. Columbus, OH. February 19-22. Keener, H.M., Elwell, D.L., Stowell, R. 1988. Composting animal mortality. Ohio Animal Disease Newsletter. 3(1):4.
Elwell, D.L., Keener, H.M. Carey, D.S. and Schlak, P.P. 1998. Composting unamended chicken manure. Compost Science & Utilization 6(2): 22-35.
Keener, H.M. 1998. Composting principles & practices for design and operation. Paper presented at Compost Process and Quality Control Training Workshop, BioCycle 28th Annual National Conference. Kansas City, Missouri. May 6.
Hong, J.H., Keener, H.M., and Elwell, D.L. 1998. The effect of continuous and intermittent aeration on composting hog manure with sawdust - progress report. ASAE Paper No. 984098. Presented at ASAE Annual Meeting. Jul 12-16. Orlando, Florida.

Progress 01/01/97 to 12/31/97

Outputs
Eleven pilot studies were conducted using four 208 liter reactor vessels for each study. Eight tests investigated composting short paper fiber amended with broiler liter at CIN ratios of 20-60. These studies focused on using Hi-Clay Alumina or aluminum sulfate (alum) as an amendment to compost to control ammonia losses. Rates of decomposition, ammonia evolution, and chemical composition of compost were determined. Results showed: a high CIN of 50-60 for the mix (as opposed to 25-30) would still give good rates of decomposition and reduce ammonia losses; pH control below 7.5,is necessary to minimize ammonia losses; alum has limited effects on reducing ammonia losses but does make the phosphorus less soluble. Conclusion - alum is not practical for ammonia control when composting short paper fiber with broiler liter. Three pilot scale composting studies were run on pullet manure (no amendment). In addition, data from an operating facility composting pullet manure was collected on temperatures and moistures. Rates of decomposition and ammonia evolution for composting periods 0-11 days, 12-29 days and 35-45 days were determined using samples from a commercial facility collected on day 0, 12, and 35 respectively. A scrubbing system for ammonia captured was analyzed. The effect of pH on evolution of ammonia from compost when ammonium sulfate was added was studied.

Impacts
(N/A)

Publications

Carey, Douglas S. 1997.(H.M. Keener, advisor). Minimizing nitrogen loss from poultry manure compost amended with ammonium sulfate. M.S. Thesis. The Ohio State University, Columbus, OH.
Das, Keshav and Keener, H.M. 1997. Moisture effect on compaction and permeability in composts. J. Environmental Engr. 123(3): 275-281.
Das, K. and Keener, H.M.1977. Numerical Model for the Dynamic Simulation of a Large Scale Composting System. Transactions of the
Ekinci, K. 1997.(H.M. Keener, advisor). Evaluation of decomposition rate, airflow rate and ammonia control of short paper fiber with broiler litter and additives - alum and sulfuric acid. M.S. Thesis. The Ohio State University, Columbus, OH.
Keener, H.M. and Elwell, D.L. 1997. Composting Large Animal Mortality. Paper presented at Livestock Conservation Institute.
Keener, H.M., Elwell, D.L., Das, K. Hansen, R.C.1997. Specifying Design/Operation of Composting Systems Using Pilot Scale Data. AppliedEngineering in Agriculture 13(6):767-772.
Keener, H.M., Hansen, R.C. and Elwell, D.L.1997. Airflow through compost: design and cost implications. Applied Engineering in Agriculture 13(3): 377-384.
Keener, H.M., Elwell, D.L.and Mescher, T.1997. Composting Swine Mortality-Principles and Operation. AEX 711-97. OSUE., Columbus, OH.
Mescher, T., Wolfe, K.,Stowell, R.and Kenner, H.M. 1997. Swine Composting Site Selection. AEX 712-97. OSUE, Columbus, OH.

Progress 01/01/96 to 12/30/96

Outputs
Eleven pilot studies were conducted using four 208 liter reactor vessels for each study. Eight tests investigated composting short paper fiber amended with broiler liter at C/N ratios of 20-60. These studies focused on using Hi-Clay Alumina or aluminum sulfate (alum) as an amendment to compost to control ammonia losses. Rates of decomposition, ammonia evolution, and chemical composition of compost were determined. Results showed: a high C/N of 50-60 for the mix (as opposed to 25-30) would still give good rates of decomposition and reduce ammonia losses; pH control below 7.5 is necessary to minimize ammonia losses; alum has limited effects on reducing ammonia losses but does make the phosphorus less soluble. Conclusion - alum is not practical for ammonia control when composting short paper fiber with broiler liter. Three pilot scale composting studies were run on pullet manure (no amendment). In addition, data from an operating facility composting pullet manure was collected on temperatures and moistures. Rates of decomposition and ammonia evolution for composting periods 0-11 days, 12-29 days and 35-45 days were determined using samples from a commercial facility collected on day 0, 12, and 35 respectively. A scrubbing system for ammonia captured was analyzed. The effect of pH on evolution of ammonia from compost when ammonium sulfate was added was studied.

Impacts
(N/A)

Publications

Das, K. and Keener, H.M. 1996. Dynamic simulation model as a tool for managing a large scale composting system. Presented at Computers in Agriculture. Jun 11-14. Cancun, Mexico.
Elwell, D.L., Keener, H.M., and Hansen, R. C. 1996. Controlled, high-rate composting of mixtures of food residuals, yard trimmings and chicken manure. Compost Science & Utilization 4(1):6-15.
Keener, H.M. and Elwell, D.L. 1996. NH3 suppression using Hi-Clay Alumina and Alum in composting short paper fiber with poultry manure. ASAE Paper No. 964076. Presented at ASAE Annual Meeting. Jul 16. Phoenix, Arizona.
Keener, H.M., Elwell, D.L., Das, K.C., and Hansen, R.C. 1996. Remix scheduling during composting based on moisture control. Transactions of the ASAE 39(5):1839-1845.

Progress 01/01/95 to 12/30/95

Outputs
The effect of moisture level on compactability and related reduction in air permeability of compost mixes were experimentally studied. Results of calculations on free air space and pressure drops as a function of bed depths for a commerical biosolids/woodchip mix and separated dairy solids indicated that at moistures greater than 60%, bed depths have to be restricted to 2.5 m to prevent high pressure drops and free air space limitations. Experiments in a municipal compost facility indicated their mixes should have an initial moisture level of 50% to minimize air channeling and achieve good decomposition rates during the first seven days. Theoretical equations were developed to analyze for kinetic parameters from pilot scale lab data. Parameters were derived from 38 studies on MSW, biosolids, food waste, poultry manure and separated dairy waste and used to evaluate airflow requirements, time fans can be off and time to first remix. A two dimensional finite difference model was implemented to solve the momentum, heat transfer, mass transfer and degradation equations. This model was used to predict spatial variations in airflow, temperature, moisture and oxygen concentrations in the composting reactor. Amount of degration, spatial homogeneity and cost of aeration were evaluated for different initial moistures, depths of bed, ambient air temperatures, and material degradabilities. Four pilot scale (208 liter) stainless steel reactor vessels were built.

Impacts
(N/A)

Publications

Hoitink, H.A.J. and H.M. Keener. 1995. Composting Organics in the Netherlands, BioCycle 36(1):37-38.
Elwell, D.L., H.M. Keener, & R.C. Hansen. 1995. Controlled, high rate composting mixtures of food wastes, yard wastes and chicken manures. Proc Seventh Intl Symp on Agr and Food Processing Wastes. June 18-20. Chicago, IL
Keener, H.M., D.L. Elwell, K.C. Das & R.C. Hansen. 1995. Specifying design/operation of composting systems using pilot scale data. Proc at Seventh Intl Symp on Agr and Food Processing Wastes. Jun 18-20. Chicago, IL
Das, K., H.M. Keener & H.A.J. Hoitink. 1995. Process control based on dynamic properties in composting: moisture and compaction considerations. Proceedings Intl Symposium on The Science of Composting. May 30-June 2. Bologna, Italy
Keener, H.M., D.L. Elwell, K.C. Das & R.C. Hansen. 1995. Minimizing the cost of compost production through facility design and process control. Proceedings Intl Symp on the Science of Composting. May 30-June 2. Bologna, Italy.
Das, K. and H.M. Keener. 1995. Effect of Moisture on compaction and the resistance to airflow in compost materials. Presented at Chicago, IL, June 18-23. ASAE Paper No. 952511. St. Joseph, MI: Am Soc of Agr Engineers.
Das, K. 1995 (H.M. Keener, advisor). Effect of aeration pathways on spatial homogeneity during in-vessel composting. Ph.D. Dissertation. Dept of Agricultural Engineering, The Ohio State University, Columbus, OH.

Progress 01/01/94 to 12/30/94

Outputs
Experimental studies of several compost mixes were conducted. Mixes of sewage sludge with ground yard waste (both fresh and recycled), ground bark (fresh only), ground pallets (fresh and recycled) and recycled wood chips were composted in pilot scale (208 liter) reactor vessels. In addition, four replications of dewatered cow manure were composted. All of these materials were studied under controlled temperature and air flow conditions with regular remixing and water addition as required to maintain 50 percent or greater moisture. Results gave rates of decomposition, airflow requirements for temperature control, dry matter loss, oxygen use, carbon dioxide production, ammonia evolution, moisture loss rates and requirements, volatile solids level, C/N ratio, and organic matter level during composting, and are being used to generate characterizations of the composting processes that are/will be used for designing more efficient and effective composting systems. Work was also conducted in conjunction with full scale, municipal compost facilities to more thoroughly characterize their operations and their sewage sludge mixes. In one case, air flow and compressibility properties of their mix were determined and pilot scale work on this mix has been done. Also, theoretical work has been done using parameters from these and earlier studies, and equations have been developed for remix frequency and moisture addition that will optimize decomposition for various mixes and operational temperatures.

Impacts
(N/A)

Publications

KEENER, H.M., W.A. DICK, C. MARUGG AND R.C. HANSEN. 1994. Composting Spent Press-molded Wood-fiber Pallets Bonded with Urea-formaldehyde: a Pilot Scale Evaluation. Compost Science and Utilization 2(3):73-82.
KEENER, H.M., D.L. ELWELL, K.C. DAS AND ROBERT C. HANSEN. 1994. Remix Frequency of Compost Based on Moisture Control. ASAE Paper No. 944066, ASAE, St. Joseph, MI.
ELWELL, D.L., H.M. KEENER, H.A.J. HOITINK, R.C. HANSEN AND J. HOFF. 1994. Pilot and Full Scale Evaluations of Leaves as an Amendment in Sewage Sludge Composting. Compost Science and Utilization 2(2):55-74.