Progress 10/01/01 to 09/30/07

Outputs
This research is aimed at exploring treatment alternatives with potential economic benefit to the dairy farmers of Louisiana. More specifically, this research focuses not only on treating animal wastes, but also on producing dry fertilizer pellets and bio-energy (biomass gasification to generate heat and electricity, bio-oil production). This research is being conducted by Chandra Theegala in the Biological and Agricultural Engineering Department at LSU. This research resulted in development of a diary manure/sand separator prototype. The manure/sand separator was installed at the LSU AgCenter's dairy on campus. A larger unit will be deployed at the SE Experiment Station dairy in Franklinton, LA. Due to the unique sand and manure separation capabilities of the design, commercialization and dissemination of the gravity screen is being pursued through the LSU AgCenter's Intellectual Property office. It is anticipated that the cost savings from reduced dredging frequency alone will offset the cost of installation of a gravity screen. Several solar stills were developed to cost-effectively dry the wet manure. A unique drying protocol was developed to generate dry, pathogen-free fertilizer pellets. Two bioenergy options were considered for the separated dairy manure. The hydro thermal liquefaction (HTL) experiments demonstrated the potential to produce crude-like oil from wet biomass. A master's student successfully defended his fundamental work in the HTL area in December 2007. Several, low-cost, down-draft biomass gasifiers were designed and built over the last 4 years. A second master's student successfully defended his work on lowering tars and particulates in the synthesis gas produced from the gasifier. A non-provisional patent was filed by the LSU AgCenter's Intellectual Property office. A Louisiana investor has agreed to commercialize the unit and has signed the necessary contracts with the LSU AgCenter.

Impacts
During the last 3 years, several self-cleaning gravity screens were constructed to separate the dairy manure from liquid stream. The final prototype uses a stainless steel wedge-wire screen and was proven to be very effective both for organic solids separation (~50%) and sand trapping (~95%). All the experiments on the gravity screens for separating dairy manure were completed in the 2006 project period. The next phase of the project focused on generating value-added products from manure. Two specific directions were considered on this project. The first option was aimed at creating a pathogen-free, dry fertilizer pellets. The second option was to use the manure as a feedstock for generating energy. Solar stills were designed and built for drying wet biomass. The final prototype was very effective in drying these wastes during the summer months, drying wet biomass (with 70-80% moisture) to less than 4% moisture in 3 summer days. Winter performance was poor during the first two years. Additional experiments using convection drying were conducted during the last two winters (Dec 2005-Feb 2006; Dec 2006 - Feb 2007). Operating the still under convection drying mode lowered the drying period from 25 days to approximately 8 days. From a bacterial standpoint, despite extremely high still temperatures in the still (> 200 oF), significant concentrations of bacteria persisted in the still-dried manure. The still drying seemed to induce heat tolerance in several bacterial strains. Despite initial hurdles, 3 years of undaunted research and help from a dedicated microbiologist (Dr. Eric Achberger) resulted in a unique technique to totally eliminate the bacterial pathogens. This technique was validated with experimental data in Summer, 2007. The 0 CFU/g beats the suggested threshold of 1000 CFU/g set for organic fertilizer use. The bioenergy experiments focused on two distinct technologies, namely hydro thermal liquefaction (HTL) and gasification. HTL, in short, involves converting biomass to bio-oils by exposing wet biomass slurries to elevated temperatures (280 oC and higher) in presence of a pressurized process gas for residence times of up to 20-30 minutes. A master's student was hired to conduct fundamental HTL research during 2006-2007. The student successfully defended his HTL work in Dec 2007. Based on the results, up to 850 lbs of oil (crude-like oil) can be produced from a ton of dried dairy manure. However, experimental practicality, net-energy balance computations, and oil characterization remain to be investigated. On the gasification arena, several down-draft gasifier prototypes were constructed in the BAE department in the last 4 years. Biomass with less than 15% moisture content is fed into an in-house-built gasifier. The synthesis gas (CO, H2, CH4) produced from gasifiers can be used for heat generation or can be further cleaned for use in engines coupled with electrical generators. A master's student was hired to work on this project during 2006-2007. The student successfully defended his work on lowering tars and particulates in the synthesis gas generated from the gasifier.

Publications

• Theegala, C.S., Small, D. and Monroe, T.W. 2008. Oxygen Electrode-Based, Single Antibody Amperometric Biosensor for Qualitative Detection of E.coli and Bacteria in Water. Journal of Environmental Science and Health, Part A. Volume A43, No.5.
• Midgett, J. 2007. Assessing a hydrothermal liquefaction process using biomass feedstocks. MS Thesis, Louisiana State University. Defended in Dec 2007, submitted thesis in January 2008.
• Akudo, C. 2007. Quantification of tars and particulates from a pilot scale, downdraft biomass gasifier. MS Thesis, Louisiana State University. Defended in Dec 2007.
• Akudo, C. and Theegala, C.S. 2007. Tar and particulate characterization from a downdraft, biomass gasifier. Conference paper for ASABE, June 17-20, 2007, Minneapolis Convention Center, Minnesota.
• Midgett, J. and Theegala, C.S. 2007. Assessing Feasibility of Bio-oil Production from Thermal Liquefaction of Biomass. Conference paper for ASABE, June 17-20, 2007, Minneapolis Convention Center, Minnesota.

Progress 01/01/06 to 12/31/06

Outputs
Several experiments were conducted using the final prototype of the gravity screen separator. This separator was used to separate the solids in the liquid waste stream at the LSU dairy facility. The entire flow from an 80-cow facility was passed through the screen. The separator had a special provision for trapping the sand lost from concrete floors. The screen performed satisfactorily and separated manure and sand with an average separation efficiency of 50% and 95%, respectively. The results were presented at the 2006 ASABE annual conference along with a technical paper. Except for exploring the commercialization potential, no further research on the screens is being planned for the 2007 academic year. The separated manure was dried in an in-house built solar still. As reported earlier (2005 AD-421 report), the summer drying performance was exceptional and the still reached temperatures as high as 225 C during summer months. The winter drying was significantly improved by the use of convection drying. One of the objectives behind the manure separation and drying processes is to produce fertilizer pellets for organic farming use. However, producing pathogen-free fertilizer pellets has been a challenge. Results indicated that the gradually increasing temperatures in the still induced "temperature tolerance" in several bacterial strains. An ongoing study provided invaluable insights into the "temperature tolerance" phenomenon. Based on these new findings, a different approach has been planned for total elimination of pathogens and fecal coliforms in the manure. New experiments will be initiated in 2007. The gasification portion of this research focuses on development of gasifiers for generating heat and electricity from dried animal manure and other organic matter. Although, the third gasifier prototype successfully produced synthesis gas, the gas purity was unacceptable for continuous operation of electric generators. In January 2006, a graduate student was assigned to test the efficiency of various gas cleaning and tar cracking components. These experiments are anticipated to be completed by Summer of 2007. Another new research was initiated in 2006 to generate bio-oil from animal waste. A reactor vessel capable of achieving high temperatures (up to 600 C) and high pressures (up to 5000 psi) was procured in April 2006. This research involves hydrothermal liquefaction of wet organic matter to bio-oils (similar to crude oil). A graduate student is currently working on this project. A third of the planned experiments was conducted in Fall 2006 and the remaining experiments are anticipated to be completed by June 2007. One project, supported by USEPA and LA DEQ, has included focus on biodegradation of waste matter from sugarcane, and its impacts on water quality. Compost tea was utilized and shows promise to enhance biodegradation, reduce air and water pollution. Another project, supported by USDA special grants funds, focuses on resource use in alligator culture. This project was started in 2006 and only preliminary data is available, but it suggests ways to reduce energy usage and enhance environmental quality in the area of alligator farming.

Impacts
This first part of this research is aimed at exploring treatment alternatives with potential economic benefit to the dairy farmers of Louisiana. More specifically, this research focuses not only on treating animal wastes, but also on producing dry fertilizer pellets and bio-energy (biomass gasification to generate heat and electricity, bio-oil production). This research is being conducted by Chandra Theegala. The second portion of this research is overseen by Steven Hall. He focuses on improving water quality and reducing energy usage in aquacultural systems.

Publications

• Small, D., Theegala, C.S., Monroe, T. 2006. Detection of Escherichia coli O157:H7 in Water using an Amperometric Biosensor. Manuscript for 2006 ASABE Annual International Meeting, Portland, Oregon, 9 - 12 July 2006.
• Theegala, C.S., Jordan. J. Reduction of Lagoon Loading by Solid Waste Separation Using a Stationary Inclined Gravity Screen. Manuscript for 2006 ASABE Annual International Meeting, Portland, Oregon, 9 - 12 July 2006.
• Hall, S.G., Schellinger, D. and Carney, W.A. 2006. Enhancing Sugarcane Field Residue Biodegradation by Grinding and the Use of Compost Tea. Compost Science and Utilization 14(1): 32-39.

Progress 01/01/05 to 12/31/05

Outputs
Bioenergy and Value Added Products from Animal Waste. Several self-cleaning gravity screens were constructed to separate the suspended waste from the liquid waste stream. The final prototype uses a stainless steel wedge-wire screen and has proven to be very effective, both for organic solids separation and sand trapping. The screen is installed at the LSU AgCenter dairy and handles the entire flow from the 80 cow dairy facility. On average, the screen separates approximately 1,500-2,000 lb of manure per day. The separator also has a novel design for trapping the sand. The separated sand can be reused as bedding material after drying. The separated manure has a high moisture content (>70%) and has to be dried cost-effectively for the stated value added applications. A solar still was designed and built for this application. Results indicated that the solar still was very effective for drying the dairy waste in summer months, drying wet biomass (with 80-90% moisture) to less than 4% moisture content in 3 summer days. Experiments on wet animal manure indicated that the solar drying process lowers the coliform numbers by several orders of magnitude, thereby opening new possibilities for production of organic fertilizer. However, the still performance during the winter months (Nov, 2004 to March, 2005) was not satisfactory. Analysis of separated manure indicated that the nutritive value is quite low (NPK of approximately 0.9%, 0.3%, 0.15%, respectively), thereby requiring fertilizer supplementation (such as blood meal, bone meal, inorganic fertilizers). New experiments are planned to address these problems. For the methane generation component of this project, a 2 liter anaerobic digester was built and was operated at 95 oF. The reactor was held in a continuous flow mode for 3 months. Results indicated that methane yield averaged (days 13-87) 1.62 L/day from a daily addition of 50g of wet manure along with 50 ml of water. Assuming a volatile solids (VS) content of 10.63% (wt of dry volatile solids/wt of wet manure), this yield corresponds to 4.867 ft3/lb-VS added. Comparing this value with the established value of 5.62 ft3/lb-VS- destroyed indicates that more than 85% conversion efficiency was obtained at this temperature. This value is significantly higher than the traditional 40-50% achieved with large-scale, out-door methane digesters. Further experiments are being planned to assess the benefits of higher digestion temperatures (through use of gasification heat or geothermal heat). For the gasification component of the project, several down-draft gasifier prototypes were constructed. Biomass with about 10-20% moisture content is fed to the gasifier. The synthesis of gas (CO, H2, CH4) produced from the gasifier successfully powered small gasoline engines (solely on gasifier produced gas). However, particulates and tars in the exiting gases limited the runtime of the engines. The principal investigator is currently working on gas cleaning and conditioning. In Spring 2006 a graduate student was put on this project and will be focusing on thermal/catalytic tar cracking and particulate removal.

Impacts
This research is aimed at exploring treatment alternatives with potential economic benefit to the dairy farmers of Louisiana. More specifically, this research focuses not only on treating animal wastes, but also on producing dry fertilizer pellets and bio-energy (methane production, biomass gasification to generate electricity, bio-oil production).

Publications

• No publications reported this period

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

Outputs
Project 1: Bioenergy and Value Added Products from Animal Waste (C. Theegala, M. Mailander). There has been a shift in the research focus after Dr. Caye Drapcho, the lead investigator on this project left LSU in Fall 2003. New research was initiated in January 2004 and was undertaken by the Renewable Energy, Byproduct Utilization, and Biosensors or REBUB team, under the direction of Dr. Chandra Theegala. The new research is aimed at exploring treatment alternatives with potential economic benefit to the dairy farmers of Louisiana. More specifically, this research focuses not only on treating animal wastes, but also on producing dry fertilizer pellets and bio-energy (methane production, and biomass gasification to generate electricity). The dry waste pellets can be marketed as organic fertilizer, methane from anaerobic digesters can be used for heating or can be used for electricity generation, synthetic gas from gasifiers can be used for electricity generation, and ash from the gasifiers can be marketed as inorganic fertilizer. During the reporting period, the REBUB team has constructed two downdraft gasifiers, solar driers/stills, greenhouse-based convection driers, and methane digesters. The second prototype of the gasifier presently produces low BTU synthetic gas (CO, CH4 and H2), which is being used to run a modified gasoline engine. The investigators are currently focusing on gas cleaning for extended use in IC engines. Methane production from anaerobic digesters has consistently exceeded 2200 ml/50 g manure per day, which is well above the usually reported values. The REBUB team is currently exploring the option of employing geothermal heat for heating the methane digesters. Separate work on use of agricultural residues with engineered structures to reduce coastal erosion is summarized in thesis work of M. Campbell (http://etd.lsu.edu/docs/available/etd-11052004-152838/) which suggests both that this may be a beneficial use of agricultural wastes but also a method to reduce coastal erosion in a cost effective manner. Finally, study of water quality under conditions of in situ composting versus other methods of residue disposal is underway. Initial results suggest that reducing particle size and introducing selected biological organisms could improve degradation rates.

Impacts
Currently, the dairy farmers in Louisiana are mandated to discharge their wastes to a single-stage no-discharge lagoon. Despite the no-discharge regulation, runoff from land applications and heavy rainfall results in contaminant and pathogen washout from the dairy facilities. A logical way of addressing this problem is to provide further treatment (such as a two stage lagoon system) for dairy waste. However, the dairy industry in Louisiana is currently operating on marginal profits and any additional treatment requirements or mandatory regulations may force many dairies to go out of business. The proposed research is aimed at exploring treatment alternatives with potential economic benefit to the dairy farmers of Louisiana.

Publications

• Publications Campbell, M.D. 2004. Analysis and Evaluation of a Bioengineered Submerged Breakwater. Masters Thesis at Louisiana State University

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

Outputs
Design plans, site selection and field surveys were completed for experimental systems that will include anaerobic/aerobic dairy wastewater treatment systems, a lagoon and constructed wetlands at the LSU AgCenter Southeast Research Station. The submerged aquatic vegetation grown in the wetlands then may be removed for transplanting into Lake Ponchartrain for enhanced restoration of the lake. In the lab, the anoxic/aerobic (A/A) system, a two-stage biological treatment effective at reducing organic carbon, nitrogen and odors in swine wastewater were operated at recirculation ratios of 1 and 2 and hydraulic retention times of 24 and 12 hours for Runs 1 and 2, respectively. Dairy waste obtained from the LSU Dairy Farm was coarse filtered and diluted to achieve a total COD concentration of 5,000 mg/L. Urea nitrogen was added to adjust the ammonia content of the waste to simulate the COD:NH3 ratio of solid dairy waste and urine. For Run 1, ammonia-N was reduced 99.8%, total COD was reduced 70%, and total inorganic N was reduced 73% at steady state. For Run 2, ammonia-N, total COD and total inorganic carbon were reduced 99.7%, 53% and 73%, respectively. In both runs, FC levels were decreased from 107 to 106 cells/mL, roughly equivalent to the reduction achieved by anaerobic lagoons with 60 days of hydraulic retention time. An automated compost control system was constructed to control temperature in bioreactors via automated aeration control. Ten thermocouples in each of four reactors were used with computer A/D and multiplexer boards to automate 12 air valves. An autonomous vehicle was used to capture water quality data from aquacultural and natural water bodies to estimate impact of pollution impacts. Development and further testing are underway.

Impacts
Open anaerobic lagoons release odorous compounds and may contaminate surface water. The A/A system may be an effective alternative for reducing nitrogen, organic carbon, FC and odor compounds in dairy wastewater. Process control can improve waste management and environmental quality. With concerns over environmental regulations, both solid wastes and their impacts on water quality are critical. Addressing waste management via improved composting methods, as well as improving monitoring and potentially management of water quality via improved automated methods will help improve our environment and assist farmers in managing valuable resources.

Publications

• Gaston, L.A., Drapcho, C.M., Tapadar, S. and Kovar, J.L. 2003. Phosphorus runoff relationships for Louisiana coastal plain soils amended with poultry litter. Journal of Environmental Quality. 32:1422-1429.

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

Outputs
Project 1: Biological treatment of swine wastewater - C. Drapcho, D. Frederick. A two-stage, continuous-flow, biological treatment system designed to treat swine wastewater was investigated. The anoxic/aerobic (A/A) system can be used for both nitrification and denitrification. A bench-scale system was efficient at a 36 hour retention time using settled wastewater from the LSU AgCenter Swine Unit. Under field conditions, the A/A system did not function as well, due to increased solids in the wastewater. At a 108 hour retention time, COD was reduced from 10,200 to 5,000 mg/L, ammonia-N was reduced from 1,210 to 630 mg/L, and nitrate-N was below sample detection limit. Only partial nitrification appeared to have occurred in the aerobic reactor, most likely due to inefficiency of the aeration system. Project 2: Impact of Poultry Litter Applications on Surface Water Quality - C. Drapcho. Surface runoff was collected after simulated rainfall from field plots located at four pasture sites in the Lake Darbonne watershed. Past poultry litter applications resulted in soil phosphorus values of 100 to 1,400 mg/kg. Mean total P in the runoff water decreased over four rainfall simulations as follows: Site 1, 5.4 to 1.0 mg/L; Site 2, 7.6 to 1.5 mg/L; Site 3, 5.9 to 3.8 mg/L; and Site 4, 7.9 - 6.7 mg/L. Project 3: Waste Treatment in Aquaculture - S. Hall, C. Drapcho. Two promising themes characterize this project. First, integration of unit operations in engineered biofilters can improve operation. A unique method showed that integrated units can achieve similar nitrification as with dedicated biofilters, while allowing other operations in a single system (Scott, 2002). Second, process control can optimize growth to improve productivity and waste management in aquatic ecosystems. A series of aquaculture tanks have been designed and built to study the effects of time-temperature histories on oyster production and the breakdown of wastes under controlled conditions.

Impacts
Open anaerobic lagoons release odorous compounds and may contaminate surface water. The A/A system may be an effective alternative for reducing nitrogen, organic carbon, and odor compounds in wastewater. Control of phosphorus from agricultural lands is needed to prevent eutrophication of surface water. These results will aid development of BMPs for control of P transport.

Publications

• Frederick, D. 2002. Anoxic/aerobic biological swine waste treatment system with odor reduction. M.S. Thesis, Louisiana State University, Baton Rouge, LA.
• Scott, J. 2002. Nitrification rates in a reversed-flow, spouted bed bioreactor applied to recirculating aquaculture systems. M.S. Thesis, Louisiana State University, Baton Rouge, LA.