Progress 09/01/10 to 08/31/13
Outputs
Target Audience: The target audience for the information provided by this research are dairy producers looking to implement anaerobic digestion systems as well as those already operating digestion systems. In addition, it will inform the dairy industry as to the possible connections that can be developed to increase partnerships which can increase technology adoption.? Changes/Problems: As part of this project, a small scale system was to be donated by a company for installation and evaluation of performance. Unfortunately the small scale company backed out of the project plan and did not provide the equipment needed to do the analysis on a pilot scale system. In order to gain the information on operation, 7 full scale systems were evaluated over the course of a year for performance. The PI was also able to provide pathogen assessment through digestion systems. What opportunities for training and professional development has the project provided? The information from this work has been used to develop a small scale digester conference to aid producers in understanding design and operation of small scale systems, as well as feasibility of implementation. In addition, the work is also being integrated into a digester operator training program used to provide agricultural digester operators with information primarily with optimization of their systems How have the results been disseminated to communities of interest? All work described above is in the process of being published through peer reviewed journals. A list of the article titles include: Evaluation of Nine Full Scale Dairy Manure Processing Systems in Wisconsin including Anaerobic Digestion and Solid/Liquid Separation Components Co-digestion of cheese whey and cheese whey permeate with dairy manure IMPACT OF ANAEROBIC DIGESTION ON THE CORRELATIONS AMONG PHYSICAL PROPERTIES OF MANURE: DENSITY, SOLIDS CONTENT AND PARTICLE SIZE DISTRIBUTION Impact of mixing on methanogen content in pilot scale anaerobic digestion systems Impact of mixing on biogas production of anaerobic digestion systems Pathogen removal through nine full scale dairy manure processing systems in Wisconsin Data is currently being presented at meetings throughout the Unites States and Canada. In addition, data is currently being incorporated into a digester operator training program to be held again in February 2015 in Wisconsin (typically have 50 in attendance). Information specific to the farms was presented at numerous meetings to provide information for optimization recommendations. Information is also being used to develop life-cycle analysis for manure systems by the PI’s research team and an economic analysis tool. This information will be made available on the eXtension What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
A small scale respirometer system was analyzed to investigate the addition of cheese whey and cheese whey permeate under a variety of conditions to determine the impact to biogas production. As many cheese processing facilities are located on or at dairies throughout the nation, it is critical to understand the potential to combine the by-products from these facilities to understand the impact to anaerobic digestion systems are form mutually beneficial partnerships. As it was found that many facilities are currently using ultrafiltration and reverse osmosis systems to produce a lower moisture cheese whey protein, cheese whey permeate (the by-product of this process) was also investigated in these scenarios. The respirometer system is designed to provide mixing and temperature control while quantifying the biogas produced from each treatment using an automated system. The biogas was collected in Tedlar gas bag and evaluated for quality using a gas chromatograph on a weekly basis. The gas chromatograph was configured to measure the concentration of CH4, CO2, and H2S in the biogas. The respirometer system was operated under mesophillic and thermophillic conditions to understand the impact to biogas production with varying amounts of cheese whey additions. Surprisingly it was found that all additions of cheese whey permeate to manure produced a greater amount of biogas than cheese whey itself. This is an important piece of information as many facilities are trying to determine if they should sell their whey product or digeste for energy. It looks as though the concentrated separated whey protein which has a higher economic value should be separated and the permeate digested to produce energy realizing the optimized economic scenario. This information was contrary to what researchers expected and additional investigation is ongoing to understand what this might be the case but may be due to the highly acidic conditions present when the cheese whey was added directly. In addition, there does not seem to be significant difference in biogas production with additions of 10% of cheese whey or cheese whey permeate. Three novel pilot scale digestion systems (each with a main tank of 55 gallons) were constructed to evaluate mixing within anaerobic digesters. Three identical 55 gallon liquid digester systems were constructed as a part of this project. These are unique automated systems which are connected to a control module which automates the feeding and mixing of the digesters. Feed tanks are filled with manure once every 5 days. The feed tanks are positioned on top of large scales which are connected to the control system, the pump is activated two times per day and the control system is set to shut off the pump once a specific mass has been added to the digester. An overflow on the digester is designed to allow the same volume that is fed to the digester to leave through the effluent pipe. A mixer is controlled by a timer and the mixing system is run on and off throughout the day. Sensors which record the temperature and pH of the manure at three locations within the digester have continuous readings which are recorded using the control module. These systems were operated under three mixing regimes (non-mixed, intermittent mixing, and continuous mixing) to determine the impact to biogas quantity and quality, microbial communities, and digester breakdown of feedstocks. It was found that unlike some other data may suggest on smaller scale systems, that mixing did not have a significant effect at the total solids concentration found in many dairies in Wisconsin. It is evident that at 6% soilds, mixing may actually reduce buildup of solids in the digester which is a positive thing to reduce maintenance, but also reduces the solids build-up that may result in greater biogas production. It was also found that the microbial communities may have shifted from one run to the next but that the communities within each digester were not as affected by the conditions from mixing as was affected and are more related to the initial communities that become dominant in the systems. Many different repirpometer runs were conducted to investigate contributions of additional waste products that may be available to small scale systems, including grasses, weeds, algae, etc. It was found that while many of these feedstocks can increase the biogas production by varying degrees, it is typically not linear and most substances have a point where additions no longer result in increased biogas production. Nine manure systems throughout the state were investigated as a part of this project for two weeks over the course of one year to investigate the performance of on-farm digestion systems. The study design included sampling every other week pre and post digestion and the solid and liquid portion after separation. This allows for assessment of the digestion process and the separation system. Samples were evaluated for nutrients and solids to determine the changes and degradation of feedstocks through the system. Researchers were also able to send samples to the USDA ARS to assess pathogens and pathogen indicators (although funding was provided through another channel for analysis). It was found that many systems could benefit from increased optimization as incomplete breakdown was achieved through many systems. Researchers continue to use the results from this study to aid digesters operators who participated in this study to increase their biogas production and to further develop the Wisconsin digester operator training. In addition, it allowed researchers to report digester performance results as well as determine the impact of additional feedstocks at specific facilities. During the completion of this study, additional components of research were conducted to collect necessary information to complete the above work. Namely, a digested manure density and particle size analysis was conducted on low solids (<10%) dairy manures as the characteristics were needed to determine design parameters for system design and operation.
Publications
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2014
Citation:
Evaluation of Nine Full Scale Dairy Manure Processing Systems in Wisconsin including Anaerobic Digestion and Solid/Liquid Separation Components
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2014
Citation:
Co-digestion of cheese whey and cheese whey permeate with dairy manure
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2014
Citation:
IMPACT OF ANAEROBIC DIGESTION ON THE CORRELATIONS AMONG PHYSICAL PROPERTIES OF MANURE: DENSITY, SOLIDS CONTENT AND PARTICLE SIZE DISTRIBUTION
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2014
Citation:
Impact of mixing on methanogen content in pilot scale anaerobic digestion systems
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2014
Citation:
Impact of mixing on biogas production of anaerobic digestion systems
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2014
Citation:
Pathogen removal through nine full scale dairy manure processing systems in Wisconsin
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: Analysis is currently being conducted on three pilot scale systems and ~100 laboratory scale systems. The pilot scale systems are currently operating to analyze mixing regimes and the methanogen microbial biomass content in conjunction with other digester operating parameters (gas production, feeding rate, etc.). This data will allow researchers to make recommendations on mixing schedules based on scientific experimentation, as mixing schedules are currently developed based on trail and error which can lead to significant losses based on the variability of inputs. These results will then be integrated into the Anaerobic Digester Operating course to maximize digester operation and also developed into presentations/publications/other extension channels to present to digester operators throughout the state and country. The small laboratory analysis systems are being analyzed for co-digestion of cheese whey and cheese whey permeate with manure. This information will be used to make recommendations as to the feasibility and suggested practices in terms of the co-digestate. The final data will be used to develop a predictive tool for biogas production from these feedstocks, which can then be used to determine the economic feasibility of co-digesting these waste types. Permitting is completed for the construction and installation of the full scale digester system. Installation is anticipated to be completed this fall for testing throughout the next year. This will serve as a demonstration and teaching site. During the development/construction of the full scale digester, an assessment of small and large digesters throughout the state has been completed to determine current performance of systems for comparison of feedstocks, system design, and operation and their effect of nutrient content and pathogens. This data was presented at the 2012 Manure EXPO poster session in July, and is being presented to a producer interest group in October 2012 to introduce efficiency and assess next steps. This data is currently being developed for publication and dissemination at state and national levels. PARTICIPANTS: PI - Becky Larson and Brian Holmes oversaw all aspects of the project including laboratory, pilot, and field scale experiments and outreach. Postdoctoral researcher - Asli Ozkaynak conducted the laboratory co-digestion research and oversaw the laboratory analysis of the full scale systems. Research Associate - Zach Zopp conducted filed scale sampling. Graduate Students - Patrick Triscari, Mike Holly, Hui Wang constructed, operated, and sampled pilot scale systems and full scale field systems. Undergraduate students - conducted sampling, aided in experiment set-up, sampling, and sample analysis. TARGET AUDIENCES: Graduate and undergraduate students were trained in experimental methods and anaerobic digestion systems. These students are targeted to develop research skills as well as be competent in digestion practices. Producers and cheese plant operators are the target groups for dissemination. Both groups are targeted to increase implementation of digestion systems and their sustainability in terms of economics. PROJECT MODIFICATIONS: The only major change in the delay in installation of the full scale digester. The delay is caused by the digester company and permitting issues. The permitting issues have been resolved and the digester company has provided a timeline and design specs. Other full scale digesters have been used throughout the year to obtain full scale system data during this delay.
Impacts
One small scale digester operator has changed his operation in terms of temperature and retention time based on the findings. This resulted in an additional 50% biogas production per day leading to greater efficiency and economic sustainability. Nine additional producers will be introduced to performance results and resulting operations that can impact their operations in October. Changes in performance will then be assessed. This information will then be developed into user tools for wide spread dissemination after assessment of participating producers. It is expected that the impact will expand as additional producers are exposed to the information. Information on co-digestion of cheese whey and cheese whey permeate with manure has resulted in a new thinking/assessment process for using cheese whey as an additional substrate. Cheese whey and cheese whey permeate vary significantly with the type of cheese processed and the cheese facility. Researchers are now developing a model for Mozzarella plants (most common cheese produced in Wisconsin) and trying to determine parameters through experimentation which dictate the biogas production. This information will be of great use to cheese facilities who are trying to make educated assessments on digestion technology implementation and to producers who are currently or plan to include cheese whey as a feedstock.
Publications
- No publications reported this period
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: Currently, there are a number of projects associated with this funding. After almost one year there has been significant progress towards the listed objectives, specifically: 1. The farm-scale anaerobic digester design and siting has been completed (phase 3). Construction is to begin in Fall of 2011 and be complete in early Spring 2012. The experimental design for the digester currently includes initial testing with manure only, which will then proceed to a co-digestion of cheese whey and manure as determined by the biomethane potential analysis. As determined from digester outreach programming for digester operators, owners, and with regulators, continued work to look at the changes in the outcomes from digesters including gas production and digestate characteristics is critical in the analysis for future use of co-products in digestion. 2. Biomethane potential analysis experimental design has been completed and the laboratory data collection is underway. A respirometer was purchased and set-up in the laboratory to complete this analysis. Two 5 gallon digesters were designed and constructed to provide the initial volume of innoculant required for this analysis. The experimental design includes co-digestion of manure with cheese whey and cheese whey permeate. The cheese whey permeate was added to the study after discussions with Wisconsin cheese production facilities as a large portion of the whey is now treated further and results in a by-product of whey permeate. The analysis is examining various percent additions of cheese production by-products to manure to determine biogas potential and final characteristics. This phase (phase 1) of the outlined study is to be completed in the next few months as outlined. 3. The mixing study experimental design and construction of systems is currently being completed, with data collection to begin in October 2011 (phase 2). Three pilot-scale systems, 55 gallons each, are near complete to look at three mixing strategies (unmixed, impeller mixed, and pump mixed). These systems will be analyzed to determine power input, homogenization, and biogas production over a range of input parameters. This research will help to expand our knowledge on mixing schemes and make recommendations to current operators. 4. A fourth pilot scale system is also under construction to provide data for the anaerobic digester operator training course. The system is to be run to produce data to aid producers in understanding the causes and solutions to their operational strategies using the feedback systems they have installed. 5. The microbial study is in the design phase. As this is to be completed in year 2 and 3, researchers are currently developing the experimental design. 6. The final phase of the study (phase 4) will be integrating the data from each of the 3 data collection phases and is to begin following completion of each of the other phases. PARTICIPANTS: PI's: R.A. Larson and B.J. Holmes have made significant progress in developing the farm scale digester at the Marshfield Agricultural Research Station. As there were many issues with the manure processing at this facility, these issues have now been resolved due to the work done by the PI's to resolve these issues and develop the siting and permitting information. PI Larson has also developed numerous outreach programs as a mean to deliver project results to relevant parties. Pabst Engineering: Pabst Engineering (K. Pabst & J. Dietrich) have developed the plans for installation of a three tank digester and associated manure handling and wastes storage systems. These design has been the result of many meetings with the project PI's and those affiliated with the project at Marshfield Agricultural Research Station. Post-Doctoral Researcher: Asli Ozkaynak is the post-doctoral researcher who has worked with PI Larson to develop the experimental design for the respirometer study. Dr. Ozkaynak has overseen the sample collection of manure and cheese by-products, has developed the 5 gallon digesters for innoculum and is overseeing the biomethane potential analysis data collection under the direction of PI Larson. Graduate Students: Graduate students have developed the mixing study experimental design, overseen the set-up of the respirometer (to run biomethane potentials), configured the gas chromatograph for biogas analysis, constructed the pilot-scale units and begun data collection under the guidance of PI Larson. Marshfield Agricultural Research Station: researchers and supervisors/managers of the Marshfield Agricultural Research Station have met with project participants to identify issues related to the siting and operation of the digester and have completed tasks required for installation. Additionally, staff scientists have aided in the development of specific requirements of the digester design for research purposes. TARGET AUDIENCES: Target audiences include digester operators and producers interested in implementing digesters. There is significant research focused on all digester operations, but there is also specific research targeted to small scale digesters and the producers on farms with less than 4oo animal units. Target audience also includes digester designers and companies that provide the technology as well as operational consultants. Additional information is extremely relevant to regulators who are looking to researchers for information on these systems and their performance and end use planning. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The investigation and development of this project has led to many additional conversations with producers, many of whom are looking into developing digesters. At the Marshfield Farm Technology Days the pilot scale digesters were put on display to discuss the anaerobic digestion process with producers and others. As a result, three new conversations with producers are underway to develop a strategic plan for implementing digesters. Additionally, two K-12 educators are looking into developing digesters for their classes to promote digester education. Additionally, the interest in small scale digestion at this outreach program has led to the small scale digestion conference development to be held in Winter 2011. This conference will be held in the future at the site of the farm-scale digester which is currently being constructed in Marshfield. In under one year, significant strides have been made. This includes education from programming, development of programming, and initial data made available to producers and regulators. As the research phases of this project continue it is expected that the data will produce valuable information to a significant audience in Wisconsin and around the United States. Additional funding is also being sought to utilize the full scale digester that is currently being constructed including land application of digestate (particularly with co-products), biogas use (including compressed natural gas, and clean-up techniques), and a number of other studies addressing the needs of 3-4 other researchers.
Publications
- No publications reported this period
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