Progress 09/01/10 to 08/31/12
Outputs
OUTPUTS: West Virginia State University operates a 40m3 pilot plant continuous stirred tank reactor (CSTR) thermophilic anaerobic digester and bioenergy research facility. This digester is unique because it has been stabilized on poultry litter without the need for chemical amendments. This research facility has been developed as a model system for the application of thermophilic digestion to poultry and other agricultural wastes. The grant provided resources for bioenergy, anaerobic digestion and waste utilization research, as well as the operation of the facility. A major objective of the grant was to work toward the sustainability of integrated renewable energy and waste management systems. A long-term experiment was continued that has been testing the efficiency, design and operation of a new pilot-scale, 1800 liter, plugflow thermophilic digester for the treatment of poultry litter. The start-up period required several months using a step-wise increase in poultry litter. This experiment demonstrated the feasibility of creating a thermophilic plugflow digester for poultry farm waste that is based on the microbial consortium from the CSTR. We also continued a long-term set of experiments to test the adaptability of thermophilic digestion stabilized solely on poultry litter. Two co-digestion experiments were conducted. The first experiment tested the co-digestion of poultry litter with increasing fractions of dairy cattle waste as co-substrate. We found that the biogas output was not diminished by the cattle waste until the cattle waste reached a high percentage. Another experiment with the CSTR evaluated whether plant biomass (hay) could be efficiently codigested with poultry litter. We found that the addition of 20% hay in the feed increased energy output in terms of biogas production. The adaptive capacity of the microbial consortium was evaluated with pyrosequencing. Specific bacterial populations were found to change in abundance demonstrating that the system had to adapt to the new substrates at the community level. We used metagenomics to compare the functional diversity in the WVSU thermophilic digester and a full-scale mesophilic German digester. The analysis utilized more than 1 Gb of DNA. Both digesters were found to be rich in glycoside hydrolase gene families and other carbohydrate-utilization genes. While some major bacterial groups were common to both digesters, the bacterial diversity profiles were less similar than the functional diversity profiles. These studies will help to increase our ability to predict the adaptive capacity of anaerobic digestion with respect to substrate composition and microbial diversity. Dr. Teodoro Espinosa and his students worked on modifying the ADM1 model for anaerobic digestion with new kinetic parameters, incorporating syntrophic acetate oxidation into the model, and evaluating stability indices. He also applied Global Sensitivity Analysis (GSA) to identify parameters that most influence the ADM1 model. In addition, surveys were disseminated to evaluate the interests of WV poultry farmers in adopting anaerobic digestion for managing farm waste. PARTICIPANTS: The Principal Investigator of the project was Dr. David Huber and the CoPI was Dr. J. Ulises Toledo. The grant supported the salaries of a part-time research scientist, full-time digester operator, postdoctoral scientist, graduate student, and undergraduate students. A collaborative research project was conducted with Christine Risch (Director), Marshall University Center for Business and Economic Research. The research of two MS degree students in the PIs laboratory was supported. Other participants in the project were Dr. Teodoro Espinosa-Solares (Autonomous Universidad Chapingo, Mexico) and his graduate students. A technician in the PIs laboratory provided research assistance. TARGET AUDIENCES: This project addressed the practical applications of anaerobic digestion and also the microbial ecology of the process. Therefore, a broad audience will benefit from this work, including scientists and engineers who study anaerobic digestion, as well as farmers and industries which use digestion to treat diverse wastes. Poultry farmers from small to medium sized farms in West Virginia were particularly targeted with the development of the plugflow digester. The grant also provided training for US students and an international group of participants including visiting scientists, technicians and students at WVSU. Graduate students in agricultural engineering from Dr. Espinosa's research group (Chapingo) participated. This research has also contributed to the capacity of the Principal Investigator to provide environmental biotechnology teaching in several undergraduate and graduate classes at WVSU. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This grant has continued to develop the WVSU anaerobic digester and bioenergy research facility as a model system for sustainable bioenergy production with agricultural wastes. Agricultural and waste biomass represents a large renewable resource for the production of bioenergy, fertilizer and aquaculture feed supplements. We have demonstrated that a thermophilic anaerobic digester stabilized on poultry litter can switch to codigestion with cattle waste, grass biomass, and thin stillage (ethanol manufacturing waste). Codigestion will improve the economics of anaerobic digestion by permitting a greater range of waste biomass substrates to be utilized. We also developed a thermophilic anaerobic plugflow digester technology for applications on poultry farms. This technology is simpler, requires less maintenance, and should be more economical for small to medium size farms than the CSTR technology. To our knowledge, thermophilic plugflow digestion has not been applied to poultry waste. Therefore, our research further extends the usefulness of thermophilic digestion and the economic viability of the process, particularly for farms. The biochemical performance and microbial ecology data derived from these experiments also will be useful for developing new environmental biotechnology applications, including novel codigestion strategies for linking waste biomass disposal and bioenergy production in a variety of industries, and will contribute to the development of a renewable energy economy. A collaborative research project was conducted with Christine Risch (Director), Marshall University Center for Business and Economic Research to evaluate the interest of WV farmers in adopting anaerobic digestion on their farms. The research of two MS degree students in the PIs laboratory was supported. Other participants in the project were Dr. Teodoro Espinosa-Solares (Autonomous Universidad Chapingo, Mexico) and his graduate students. This research also contributed to the capacity of the Principal Investigator to provide environmental biotechnology teaching in several undergraduate and graduate classes at WVSU. In addition, the following presentations (and abstracts) were made at professional society meetings:1) Limitations of Bacterial Community Adaptation During Co-digestion in a Thermophilic Anaerobic Digester; Deepak Sharma, Teodoro Espinosa-Solares, David H. Huber; American Society for Microbiology Annual Meeting, Abstract and Poster, New Orleans (LA), May 2011; and 2) Bacterial Community Dynamics During Codigestion in a Thermophilic Anaerobic Digester; Deepak Sharma, Teodoro Espinosa-Solares, David H. Huber; West Virginia Academy of Science Meeting, April, 2012.
Publications
- Singh, M., D.L. Reynolds, K.C. Das. 2011. Microalgal system for treatment of effluent from poultry litter anaerobic digestion. Bioresource Technology 102:10841-10848.
- Alvarado, A., E. Nafarrate, D. Huber, N. Balagurusamy. 2012. Microbiologia de la digestion anaerobia. In: Avances Tecnologicos en la Produccion de Bioga: Perspectivas y Retos (eds. N. Balagurusamy, K.C. Das). Editorial Academica Espanola, LAP LAMBERT Academic Publishing Gmbh and Co. KG.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: West Virginia State University operates a 40m3 pilot plant thermophilic anaerobic digester and digester research facility. This digester has been stabilized on poultry litter for a decade and serves as a model system for the thermophilic digestion of animal waste and other types of organic wastes. A long-term experiment was continued which tests the efficiency of the WVSU digester to codigest poultry litter and ethanol manufacturing waste (thin stillage). Replicate laboratory digesters were used to test the efficiency of different percentages of stillage in codigestion. We found that methane production increased through 60% stillage but decreased at 80%. This experiment demonstrated that codigestion of poultry waste and stillage can increase the bioenergy output of a thermophilic digester, but digester operators must monitor the ratios of these substrates. Microbial population responses to the changes in substrate were examined by targeting rDNA markers with pyrosequencing. Analysis of metagenomic data from the pilot plant digester has provided metabolic diversity profiles that are shedding light on the digester foodweb. Recruitment plot analysis has shown that nearly six percent of the 1.2 million DNA sequences map to three different genomes of Clostridium thermocellum. This analysis has shown that this thermophilic digester is rich in bacterial populations that have metabolisms similar to known cellulose-degraders, but are distinctly different species. Publications are being written for these experiments. The objectives also included improvements to the pilot plant facility and an expansion of its experimental capability. Two 500 gallon aerobic filter reactors were set-up to treat the effluent from the pilot plant digester. The start-up of these reactors was successful, and future experiments will test their capacity to remove COD. A 500 gallon plugflow digester was designed and installed. This digester will expand the experimental capacity of the WVSU facility. Dr. Teodoro Espinosa (Autonomous Universidad Chapingo, Mexico) and his graduate student worked on revising the ADM1 model for anaerobic digestion to include the activity of fatty acid degrading bacteria. ADM1 is a mathematical model that predicts the performance of a digester depending on input variables. They incorporated new parameters into the model and conducted simulations. A publication is being written for this study. The grant also funded an experiment that was carried out by a collaborator, Dr. K.C. Das (University of Georgia), to test whether effluent from digested poultry litter can be used as a nutrient source for the growth of algae. The growth characteristics of several algal species were tested. Three different dilutions of effluent were tested as nutrients. Effluent was found to be sufficient to support growth without additional supplementation of synthetic fertilizer. Algae are a promising method to remove CO2 from the biogas of anaerobic digestion and thereby further reduce the effect of animal waste on greenhouse gas emissions. PARTICIPANTS: The Principal Investigator of the project was Dr. David Huber; the CoPI was Dr. J. Ulises Toledo. The grant supported the salaries of a part-time research scientist, full-time digester operator, postdoctoral scientist, and several undergraduate students. The research of an MS degree student in the PIs laboratory (Deepak Sharma) was supported. Other participants in the project were Dr. Teodoro Espinosa-Solares (Autonomous Universidad Chapingo, Mexico) and a graduate student from Chapingo who worked with Dr. Espinosa. A technician in the PIs laboratory provided assistance. Several WVSU undergraduate students also assisted in the project. EnviroControl Ltd (UK) was contracted to assist with the plugflow digester. TARGET AUDIENCES: This project addressed the practical applications of anaerobic digestion and also the microbial ecology of the process. Therefore, a broad audience will benefit from this work, including scientists and engineers who study anaerobic digestion, as well as farmers and industries which use digestion to treat diverse wastes. This grant also provided training for US students and an international group of participants including visiting scientists, technicians and students at WVSU. Dr. Espinosa's research group (Chapingo) benefited, particularly his graduate student who spent the summer (2010) at WVSU working on the ADM1 model. Ms. Mpabanga (technician) who contributed to the research is a native African from Zimbabwe. Mr. Sharma (MS student) who contributed to the research is a native of Nepal. This research has also contributed to the knowledge base that the Principal Investigator uses for teaching his undergraduate and graduate classes at WVSU: Environmental Microbiology (BIOL 460/660), and Current Concepts in Biotechnology (BT567). PROJECT MODIFICATIONS: The termination date for the project was extended to August 2012.
Impacts
This research has continued to develop the WVSU digester facility as a model system for sustainable bioenergy production using agricultural wastes. We demonstrated that a thermophilic anaerobic digester stabilized on poultry litter can switch to codigestion with thin stillage (ethanol manufacturing waste). We also showed that there are limits to the percentage of stillage that can be accommodated by co-digestion. This data will be useful for evaluating the use of codigestion for organic waste disposal and bioenergy production in agriculture and various industries, and will contribute to the development of a renewable energy economy. Another important impact of this grant was the support of the education of MS degree and undergraduate students at WVSU and Chapingo. Four presentations (and abstracts) were made at professional society meetings as follows. 1. International Society for Microbial Ecology Symposium, August 2010, Seattle (WA), Ami M. Smith, David H. Huber. Anaerobic digester metagenome reveals microbial community structure and genetic potential. 2. International Society for Microbial Ecology Symposium, August 2010, Seattle (WA), Deepak Sharma, Teodoro Espinosa-Solares, David H. Huber. Microbial community dynamics and performance of a thermophilic anaerobic digester following a switch to co-digestion. 3. American Society for Microbiology Annual Meeting, 2010, San Diego (CA), abstract and poster. Teodoro Espinosa-Solares, Ami M. Smith, David H. Huber. Resilience evaluation of a pilot plant digester under thermophilic conditions during a change from mono- to co-digestion. 4. American Society for Microbiology Annual Meeting, 2010, San Diego (CA), abstract and poster. Tandie Mpabanga, Ami M. Smith, David H. Huber. Stable isotope probing to identify glucose-utilizing bacteria in anaerobic digestion.
Publications
- Valle-Guadarrama S, Espinosa-Solares T, Lopez-Cruz IL, Domaschko M. 2011. Modeling temperature variations in a pilot plant thermophilic anaerobic digester. Bioprocess and Biosystems Engineering. (DOI: 10.1007/s00449-010-0488-5)
- Espinosa-Solares T, Domaschko M, Robles-Martinez F, Duran-Paramo E, Hernandez-Eugenio G, Bombardiere J. 2010. Short-term effects of temperature changes in a pilot plant for the production of biogas from poultry litter. Universidad y Ciencia 26(3):247-254.
- Rivera-Salvador V, Aranda-Barradas JS, Espinosa-Solares T, Robles-Martinez F, Toledo JU. 2009. El modelo de digestion anaerobica IWA-ADM1: Una revision de su evolucion. Ingenieria Agricola y Biosistemas. 1(2):109 -118.
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