Item No. 1 of 1

INVESTIGATOR: Kommalapati, R. R.

PERFORMING INSTITUTION:
PRAIRIE VIEW A&M UNIVERSITY
P.O. Box 519, MS 2001
PRAIRIE VIEW, TEXAS 77446

ENERGY AND NUTRIENT RECOVERY FROM GOAT MANURE BY ANAEROBIC CO-DIGESTION WITH COTTON GIN TRASH AND FOOD WASTE

NON-TECHNICAL SUMMARY: Confined animal feeding operations (CAFO) are confronted with air quality concerns pertaining to emission of ammonia, hydrogen sulfide, particulate matter and greenhouse gasses. Manure laden runoff with high concentrations of nutrients also poses a water pollution problem to surface and groundwater resources. Effective management of manure and agricultural wastewater is key to improving sustainability of livestock operations and limiting their impact on the environment. Anaerobic digestion (AD) is a proven treatment technology that treats wastewater and generates renewable methane and stable biosolids as effluent. Integrating waste feedstock from multiple sources offers an attractive option to overcome the constraints of small-scale livestock operations. The proposed research would address agricultural sustainability issues at the International Goat Research Center (IGRC) at Prairie View A&M University (PVAMU), by focusing on the development of a novel and integrated waste management approach to anaerobically co-digest goat manure, cotton gin trash and food wastes to generate renewable energy and produce nutrient rich biosolids. The proposed project would initiate extensive collaborative research between Colleges of Agriculture and Engineering at PVAMU by applying engineering principles to validate and optimize a 2-stage lab-scale AD system capable of handling manure sludge at IGRC. Lifecycle assessment of AD process would be offer a comprehensive approach to elucidate the environmental and cost-benefit analysis of agricultural waste management. Impact of chemical additives and fly ash on process kinetics and reliability will offer valuable information on fertilizer recovery from manure waste.

OBJECTIVES: The overarching goal of the project is to develop an integrated waste management solution via anaerobic co-digestion of GM with CGT and FW to recover methane and nutrient-rich biosolids. This goal is realized through the following objectives:1. To validate and optimize a 2-stage AD process for co-digestion of GM with CGT and FW and produce renewable bioenergy (methane) and fertilizer (nutrient-rich biosolids) as valuable byproducts 2. Elucidate the environmental benefits (air, water and GHG emissions) of the AD process through LCA3. Evaluate the impact of biosolids application on physical and chemical aspects of agricultural soil quality

APPROACH: Task 1: Substrate CharacterizationGM from the waste lagoon at IGRC and FW from the primary dining facility on PVAMU campus will be obtained and stored at 4oC before testing. Samples of CGT will be obtained from three regional gins in Texas and stored at room temperature.Characterization of GM from IGRC and FW from PVAMU campus will be done by quantifying total solids (TS), volatile solids (VS), chemical oxygen demand (COD), pH, TN, TP according to Standard methods for examination of water and wastewater. The water quality testing equipment including Shimadzu TOC-L, StableTemp undercounter BOD incubator, Thermo Advanced Protocol convection incubator, part of environmental engineering laboratory in the College of Engineering will be utilized to conduct these analyses.Additional elemental characterization of GM, CGT and FW will be performed with Thermo Scientific Flash 2000 CHNS/O Combustion Elemental Analyzer available at CEES, PVAMU.C/N ratios of GM, CGT and FW to be used in BMP determination will be established and compared with existing literature to determine the accuracy of baseline values.Characterization of three locally available CGT samples will be done by quantifying ash, total digestible nutrient, cellulose, lignin and hemi-cellulose contentsDetermination of particle size distribution of individual and mixed feedstocks will be made using zetasizer Malvern Zetasizer nano zs available at CEES, PVAMU.Task 2: Determination of BMPIdentification of three suitable sources of inoculum for mesophilic and thermophilic stages of AD process will be done from a survey of active single and 2-stage anaerobic reactors in geographic proximity and a documentation of feed compositions for each inoculum source will be developed.Inoculum will be prepared by degassing and incubation to remove any residual biochemical oxygen demand (BOD) continued degassing will until no significant methane production is observed (up to 5 days).Activity tests of acetate and cellulose in the inoculum will be performed to assure quality, with 1 atm overpressure of H2/CO2 for hydrogen oxidizing methanogens, 1 g/L acetic acid for acetoclastic methanogens and 0.5 g/L propionic and butyric acid for acetogenic bacteria, as per standardized methods.Estimates for volume of inoculum will be calculated according to approach described in Angelidaki & Saanders, (2004) and sample dilutions will be prepared for GM, CGT and FW with water in the range of 5-100%.Purging the BMP test bottles with gas mix of 70-30% N2/CO2 will be done and the prepared dilutions will be stored at 35oC to estimate BMP of four different feedstocks: GM, GM+CGT, GM+FW, GM+CGT+FW, as specified in existing literatureStatistical analysis including linear, non-linear regressions, correlation coefficients and ANOVA will be conducted to study relation between feedstock particle size distribution and kinetics of biogas production.?Task 3: Process optimization of Lab-Scale 2-stage AD ProcessA lab-scale 2-stage AD process as specified, with a typical working volume ratio of 7:1 for the methanogenic stage reactor to hydrogen producing stage reactor will be built with inputs from a review of existing 2-stage AD processes.The two reactors will be in a completely mixed condition and equipped with temperature and pH probes, available in CEES, PVAMU. A semi-continuous feeding procedure and cumulative SRT as derived from BMP tests will be maintained.Trial runs will be conducted to optimize the relative SRT ratios of stage-1 to stage-2 reactor and pH variation during the trial runs would be recorded to estimate selection and preparation of pH control reagents.The temperature of stage-1 reactor will be maintained in the mesophilic range of 35-38 oC and stage-2 reactor will be in the thermophilic range of 55-60 oC, satisfying the conditions laid out in EPA, Part 503 biosolids rule.Gas flow-meters will be installed in both reactors to measure daily biogas production volume and composition of CH4, H2, CO2 in the biogas will be measured by the connected Shimadzu Gas Chromatography - Mass Spectrometer: GCMS-QP2020.The performance of each stage AD process as a function of process variables, and chemical additives (fly ash and MgCl2).Chemical characterization of biosolids and effluents from 2-stage AD process will e conducted with Thermo Scientific Flash 2000 CHNS/O Combustion Elemental Analyzer available at CEES, PVAMUTask 4: Lifecycle Assessment of 2-stage ADBased on our expertise in LCA of different renewable energies, we also propose to conduct a LCA task of goal manure treatment with 2-AD to estimate reductions in air, water and GHG emissions. The task will includedevelopment of an emissions inventory database from the literature,computation of the energy cost, water consumption, and GHG emissions of during the 2-stage AD using some developed models,integration with the SimaPro® databases to predict the reductions, with the system boundaries and process flow for the reference case and the 2-stage AD case.The scenario of the reference case includes the individual processes of goat manure, cotton gin trash and food waste disposal, and the total emissions will be obtained from the summation of the individuals.The energy and water use, and GHG emissions calculated from the 2-stage AD case will be compared with not only the reference case, but also other aerobic wastewater treatment processes for handling manure sludge, such as aerated lagoons, activated sludge process, published in literature. The study of LCA will help to identify the optimum cost/benefit criteria for the AD process.Task 5: Evaluating impact of biosolids application on agricultural soilsA greenhouse pot experiment will be conducted at the university farm of PVAMU to investigate the impact of biosolids application on the physical and chemical characteristics of agricultural soil quality. The production of biosolids from AD process in the lab-scale will be not sufficient for field experiments.The experimental design will use a split-plot arrangement in a completely randomized design. Where four biosolids types (GM, GM+CGT, GM+FW, GM+CGT+FW) be assigned to the main plots, while three biosolids application rates based on the biosolids' Nitrogen content (half the recommended rate, recommend rate, and double the recommended rate for the selected crop) will be assigned to the subplots.Each treatment will be replicated three times. All treatments will be planted with Egyptian spinach after amendment with biosolids. All plots will be irrigated with an equal amount of water using drip irrigation system.Soil sampling will be carried out before planting and after harvesting. Soil physical (bulk density, porosity, texture) and chemical (pH, organic matter, calcium carbonate, available P, available K and total nitrogen) properties will be measured and analyzed following standard methods.Leaf and root biomass produced in each treatment will be measured to identify and optimize the best application rate of biosolids.Task 6: Training and leadership developmentPeriodic meetings will be organized between PIs and students to guide and assist in the development of leadership skills as well as to address technical training and assess project progress.Quarterly agricultural and engineering collaborative workshops will be conducted to provide professional development training to post-doctoral fellows and engage in mentorship/leadership activities.Workshops and educational modules will be developed to be used for CAFO waste management training to regional livestock operations and community participants.Yearly evaluation outcomes will be incorporated by the PI and disseminated through the above three events to improve productivity of research

PROGRESS: 2020/02 TO 2021/01
Target Audience:The scientific community in the broader areas of waste management, manure handling, renewable energy production, and PVAMU student community. Also, the Agricultural community can benefit from the enhanced productivity and sustainability of animal feeding operations. Changes/Problems:The research Team sought one-year extension and received the extension for one year. The research was adversely impacted due to restrictions of personnel being able to work in the university labs due to covid 19. What opportunities for training and professional development has the project provided?To date, this project has trained 2 postdoctoral candidates, 2 graduate students, and 8 undergraduate students in research activities for developing characterization procedures for goat manure, food waste and cotton gin trash, and biomethane potential determination. How have the results been disseminated to communities of interest?As provided in the publication list, during this reporting period, one graduate poster presentation was made by the graduate researcher; to demonstrate the research findings to the peer research community. Currently, one manuscript from the project is accepted and two more have been submitted to the peer-reviewed journals, and both are currently under review. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, the effluents (from GM co-digestion with SG, RS, and RS) will be evaluated for total P, Kjeldahl N, volatile acids, ammonium, and nitrate nitrogen, calcium carbonate (inorganic carbon), organic carbon, and tested for their potential as bio-fertilizers and soil amendments on plants in greenhouse trials. A life cycle assessment to evaluate bio-methane production from the co-digestion of goat manure with food waste and agricultural residues will also be conducted.

IMPACT: 2020/02 TO 2021/01
What was accomplished under these goals? Non-Technical Summary Confined animal feeding operations (CAFO) are confronted with air quality concerns pertaining to the emission of ammonia, hydrogen sulfide, particulate matter, and greenhouse gasses. Manure-laden runoff with high concentrations of nutrients also poses a water pollution problem to surface and groundwater resources. Effective management of manure and agricultural wastewater is key to improving the sustainability of livestock operations and limiting their impact on the environment. Anaerobic digestion (AD) is a proven treatment technology that treats wastewater and generates renewable methane and stable bio solids as effluent. Integrating waste feedstock from multiple sources offers an attractive option to overcome the constraints of small-scale livestock operations. The proposed research would address agricultural sustainability issues at the International Goat Research Center (IGRC) at Prairie View A&M University (PVAMU), by focusing on the development of a novel and integrated waste management approach to anaerobically co-digest goat manure, cotton gin trash, and food wastes to generate renewable energy and produce nutrient-rich bio-solids. The proposed project would initiate extensive collaborative research between Colleges of Agriculture and Engineering at PVAMU by applying engineering principles to validate and optimize a 2-stage lab-scale AD system capable of handling manure sludge at IGRC. Lifecycle assessment of the AD process would be offering a comprehensive approach to elucidate the environmental and cost-benefit analysis of agricultural waste management. Impact of chemical additives and fly ash on process kinetics and reliability will offer valuable information on fertilizer recovery from manure waste comprehensive approach to elucidate the environmental and cost-benefit analysis of agricultural waste management. The impact of chemical additives and fly ash on process kinetics and reliability will offer valuable information on fertilizer recovery from manure waste. Details of the work done this year As proposed by the PIs the objectives 1 & 3 are completed or in progress. During this reporting period, the daily and cumulative data from GM-FW co-digestion assays were analyzed and kinetic parameters utilizing two non-linear regression models were calculated and compared. It was observed that the modified Gompertz model was a better fit for the co-digestions. The maximum biodegradability of 97.4% was achieved in GM-FW co-digestion having 60% GM. The potential of effluents from GM-CGT co-digestion (details included in the previous report) as bio-fertilizers was evaluated by analyzing the available nutrients (nitrate, ammonium, orthophosphate) utilizing standard HACH kits. The data revealed that co-digestion did not improve the concentration of water-soluble/available forms of these nutrients. Other than these experiments findings the anaerobic co-digestion of GM and sorghum (SG, mentioned in the previous reporting period) was optimized. Details of the experimental work during this reporting period are provided in the following sections. Task 1. The substrate (SG, RS, and RH) characterization Sorghum samples were collected from the field research trials being conducted at the Department of Soil and Crop Sciences, Texas A&M University, College Station. Rice residues were collected from Gulf Pacific Co. (Houston, TX). The fresh goat manure (GM) was collected from the International Goat Research Center (IGRC), Prairie View A&M University (PVAMU). The inoculum for biomethane potential (BMP) assays (in triplicates) was collected from a municipal wastewater treatment plant (operating under mesophilic conditions) at PVAMU. The substrates and inoculum were characterized for moisture, total and volatile solids. The chemical oxygen demand (COD), and pH of rice residues were also determined. The C/N ratio of all substrates was determined using a CHNO/S element analyzer. The new substrates; rice straw (RS) and rice husk (RH) had C: N ratios of 66.8 and 66.5, respectively, while SG (introduced in the last reporting period) had a C: N ratio of 41:0. Task 2. Major findings from Biomethane potential assays The laboratory-scale triplicate BMP assays were conducted in 250 mL serum bottles under mesophilic temperature conditions and GM was co-digested with SG, RS, and RH. Sodium bicarbonate as a buffering agent was added to all serum bottles. When GM was co-digested with SG in various proportions (10-90%). All of the co-digestions (10-90% sorghum) yielded higher biomethane than GM mono-digestion. While the GM-RH co-digestions yielded lower biomethane than GM mono-digestion. Among the co-digestion having 60% RH yielded the highest biomethane. A bioreactor of 2 L capacity was designed and tested during this period. The findings of these experiments (still in progress) will be shared in the next reporting period. Task 4. Data analysis The anaerobic process was simulated by employing a modified Gompertz equation and the first-order kinetic equation, and high co-relation coefficients (between experimental and predicted BMP) were observed. The enormous data generated from BMP assays were statistically analyzed and interpreted. Our findings are comparable to the results from previous studies.

PUBLICATIONS (not previously reported): 2020/02 TO 2021/01
1. Type: Journal Articles Status: Awaiting Publication Year Published: 2021 Citation: Harjinder Kaur, Raghava R. Kommalapati. 2021. Effect of inoculum concentration and pretreatment on biomethane recovery from cotton gin trash, âJournal of Agricultural Scienceâ (in press).
2. Type: Journal Articles Status: Under Review Year Published: 2021 Citation: Ayobami Orangun, Harjinder Kaur, Raghava R. Kommalapati. 2021. Batch anaerobic co-digestion and biochemical methane potential analysis of goat manure and food waste, Submitted to âEnergiesâ (Under Review).
3. Type: Journal Articles Status: Under Review Year Published: 2021 Citation: Harjinder Kaur, Raghava R. Kommalapati. 2021. Optimizing anaerobic co-digestion of goat manure and cotton gin trash via biomethane potential assays and mathematical models, Submitted to the âSN Applied Sciencesâ (Under Review).
4. Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Mahmoud Soliman, Harjinder Kaur, Raghava R. Kommalapati. Characterization of Rice Residues for Biogas Production by Co-digestion with Goat Manure. Poster presentation, Virtual American Institute of Chemical Engineers Annual Conference, November 16-20, 2020.