Source: CLARKSON UNIVERSITY submitted to NRP
RESOURCE RECOVERY AT SMALL FARMS USING ANAEROBIC DIGESTION: A VIABLE TECHNOLOGY EDUCATION AND OUTREACH EFFORT
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1012210
Grant No.
2017-68006-26346
Cumulative Award Amt.
$500,000.00
Proposal No.
2016-10884
Multistate No.
(N/A)
Project Start Date
Apr 15, 2017
Project End Date
Apr 14, 2022
Grant Year
2017
Program Code
[A1601]- Agriculture Economics and Rural Communities: Small and Medium-Sized Farms
Recipient Organization
CLARKSON UNIVERSITY
8 CLARKSON AVENUE
POTSDAM,NY 13699
Performing Department
Civil & Environmental Eng.
Non Technical Summary
Anaerobic digestion (AD) of farm residues can benefit farmers not only as a renewable heat and power source, but also through solids recovery, odor, pathogen, and vector attraction reduction while producing a stabilized solids fertilizer. While AD installations at large farms have increased in the U.S., smaller farms have not taken advantage of AD technology. We and others have demonstrated on the pilot-scale the economic viability of modular AD technology for dairy farms of small to medium scale (25-500 cows). Yet, our research suggests that small-to-medium-scale farmers with interest still perceive economic and technological hurdles of AD technologies especially with regard to the intergration at their operations that no longer exist. There remains a knowledge gap between potential AD users and developers of AD technologies: we hypothesize that these farmers will make better informed decisions about adoption of AD technology appropriate for their farms if they are exposed to viable scale dependent options. Our goal is to integrate our prototype digester at the Cornell Cooperative Extension Farm with farm exisitng processes (e.g. greenhouse, commercial kitchen) to optimize energy, nutrient flows and use it to educate stakeholders about AD systems for smaller-to-medium dairy farms. Data on system performance and educational materials will be broadly disseminated to promote adoption of integrated AD technology. This comes at an opportune time in New York, where the threshold for designation as a medium sized confined animal feeding operations (CAFO) has recently been relaxed from 200 to 300 cows to promote expansion in dairy industry and farm productivity. So farmers with less than 300 cows do not have to comply with regulations applicable only to larger CAFO's.
Animal Health Component
60%
Research Effort Categories
Basic
10%
Applied
60%
Developmental
30%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
40334702020100%
Knowledge Area
403 - Waste Disposal, Recycling, and Reuse;

Subject Of Investigation
3470 - Other dairy cattle products;

Field Of Science
2020 - Engineering;
Goals / Objectives
Anaerobic digestion of farm residuals represents and opportunity for energy and resource recovery while improving farm sustainability. Prior research indicates that digesters especially at the smaller scale are not economically viable unless benefical recovery of bedding fibers or co-digestion of high strength wastes has been considered. The overarching goal of this project is to demonstrate that a digester system could be effectively integrated into small farm operations. Building of our exisitng infrastructure at the Cornell Cooperative Extension Farm in Canton, NY the demonstration system will include bedding recovery, co-digestion of waste generated in a kitchen and biogas use to heat a germination greenhouse. Workshops with area farmers will be conducted to further improve the efficiency of the integrated waste to recovery process.
Project Methods
The main goal of this study is to improve design of anaerobic digester systems for small farms and expose, educate and train stakeholders to the technology so better informed decisions will be used when assessing potential digester applications.Working with the CCE dairy specialist for the Northern New York region we will construct dairy farmer focus groups for farms that practice confinement feeding and milk 49 cows or less, 50 to 99 cows, 100 to 199 cows, and 200 to 299 cows. Per standard focus group methodology, each homogenous group will contain approximately 7 farmers (Adler and Clark, 2008). Each farmer participating in the interviews will receive a $25 stipend and information packets on AD technologies. The interviews will be held at the Extension Learning Farm of St. Lawrence County where the pilot project is housed and we will employ the following methodology.1. Assemble and brief introductions.2. Provide farmers with a series of questions regarding their knowledge of AD technologies and their interest in such technologies for their farms.3. Provide a presentation to the farmers on the pilot project including data produced and a tour of the facility.4. Answer questions of the farmers.5. Re-interview farmers about knowledge of AD technology and their interest in it.6. Adjourn.In this way we hope to measure the degree and composition of the reluctance to adopt AD technologies on smaller farms, and how providing information on an AD technology designed specifically for smaller dairy farms can change attitudes and knowledge. Farmers should be able to articulate the degree to which AD technologies do or do not fit their farming systems and whether the information provided addressed any concerns or not. This information will be very useful to engineers associated with this project and others interested in small-farm viability, especially as it relates to addressing current and future environment and energy issues and problems.Data acquired from the research and education/extension activities that will be carried out to achieve these goals will be divided into direct and indirect. Data collected directly as a result of a measurement (i.e. raw data) will include coded survey responses, chromatographic data, electricity use, propane use, and other chemical (e.g., chemical oxygen demand, carbohydrates, nutrients, volatile fatty acids, pH), physical (e.g., total and volatile solids, temperature, flow rate, hydraulic residence time, solids residence time), and biological (e.g., biogas production, biogas methane content, pathogens) parameters. The effect of feedstock on digester performance and digester performance characteristics as determined by modeling (e.g., biokinetic parameters, efficiency, biogas production rates, etc.) will be considered indirect (i.e. calculated) data.Both direct and indirect data will be subjected to descriptive and/or interpretive statistical analysis. Experiments regarding solid waste feed stocks for anaerobic digestion will be replicated a minimum of three times. Comparisons between feed stocks will be made using two-way analysis of variance (ANOVA) and Tukey's test (P < 0.05) (SigmaStat v. 4.0, SPSS, Inc., Chicago, Ill.). Data will be check for normality prior to statistical analysis and appropriate non- parametric alternative statistical tests used as needed. Both quantitative and qualitative approaches will be used to analyze data collected during farmer interviews.

Progress 04/15/17 to 04/14/22

Outputs
Target Audience:Over the course of the project we engauged area dairy and beef farmers, producers, K-12 students, and college students in the project. Farmers and producers attended workshops about anaerobic digestion at the Cornell Cooperative Extension Farm in Canton, NY and observed the demonstration digester system that could treat both dair manure (slurry and packed bed), and foodwaste. Solids could be recovered using an installed screw press while biogas was used to heat the digester and the local seedlings green house during the beginning of the growing season. Changes/Problems:COVID significantly affected the direct interaction of the project team with area farmers for two years of the project. Results from the treatment of the mixed wastes are still being analyzed and interepreted before submission to a peer reviewed journal. What opportunities for training and professional development has the project provided?Training of area producers and farmers through workshops was accomplished. Integrating resource recovery learning modules in area high school educated more than 500 K-12 students about the value of resource recovery of organic waste and integrating resource recovery processes at farms. How have the results been disseminated to communities of interest?Results were reported at conferences, journal publications and workshops organized for area farmers What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Close to 100 farmes participated in workshops organized by the project team. In addition more than 500 middle and highschool students learned about resource recovery from farm and food waste through anaerobic digestion. Data generated through the operation of the digester system will be used journal publications so that the data will be available to system designers. Results gathered through the project indicate that a the use of both foodwaste and dairy manure will generate significant more energy yet reduce the amount of solids to be recovered from the digester system. So optimum operational conditions depend on the need of resources for the farm.

Publications


    Progress 04/15/21 to 04/14/22

    Outputs
    Target Audience:Farmers as well as students from college, middle and high schools Changes/Problems:COVID significantly affected our planned outreach to area farmers. We pivoted to partner with the local public school to reach middle and high school students teaching them about the value of resource recovery in agricultural systems. In addition we presented out survey results from the completed farmer workshops in peer reviewed journals. Lastly, the demonstration system, which has been operated continously for 5 years integrating manure and foodwaste treatment, recovering energy (through biogas) and solids for bedding will be used in the next three years as we will continue to evaluate the synergistic effects of co-digestion of dairy manure and foodwaste through continued USDA funding. The goal of that project will be to develop an economic model that can be used by area farmers to evaluate the intergrated waste resource recovery system especially in light of recent regulations to divert organics from the solid waste stream. Thus that waste stream now will need to be treated in either dedicated composting or anaerobic digester facilities or could be treated in farm treatment systems thus providing another revenue stream for area farmers. What opportunities for training and professional development has the project provided?Approximately 60 High School students participated in a field trip to the learning farm of CCE where the digester is located that treats the CCS cafeteria. Students learned about animal care, greenhouse operation, maple syrup production and anaerobic digestion. Plans for workshops2021 were thwarted by the coronavirus pandemic; however, the PI's were able to provide an equivalent teaching workshop in an online format for a national teaching conference for engineering educators (ASEE, June 2020), and further outreach through a national engineering education conference (ASEE, July 2021) and a workshop at the Science Teachers Association of New York State (STANYS, November 2021). How have the results been disseminated to communities of interest?Presentations at conferences, site visits with high school students, publications What do you plan to do during the next reporting period to accomplish the goals?finish publications resulting after detailed analysis of the collected data

    Impacts
    What was accomplished under these goals? Through this project we demonstrated that solids can be recovered when treating dairy manure. Solids recovery is reduced when treating foodwaste as foodwaste consists of biodegradable solids. Methane production increases with the addition of foodwaste. Thus, depending on the use of the digester products (biogas, recovered solids) the optimum blend of dairy manure and foodwaste may vary. The project demonstrated the beneficial use of co-digestion of dairy manure and foodwaste. The system has been operated continously for 6 years producing a comprehensive data set for process evaluation.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2022 Citation: DeWaters, J.; S.J. Grimberg (2022) Food Waste-to-Energy: A project-based school learning experience. Researchoutreach, 128. https://researchoutreach.org/articles/food-waste-energy-project-based-school-learning-experience/. DOI: 10.32907/RO-128-2236048339. Accessed 2/7/22.
    • Type: Journal Articles Status: Submitted Year Published: 2022 Citation: Lennox, B; D. H. Hilderbrandt, S.J. Grimberg, S. Rogers; J. Welsh Feasibility of Small Scale Anaerobic Digester to Treat Dairy Waste. Submitted to Transactions of the ASABE
    • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Burdick, J; M. Smith; J.E. DeWaters, S. Grimberg (2022) Food to Energy: Transforming Food Waste into a Valuable Product via Poopy Power. Workshop presented at the National Agriculture in the Classroom Conference, June 28  July 1, 2022 in Saratoga Springs, New York.


    Progress 04/15/20 to 04/14/21

    Outputs
    Target Audience:The target audience during this reporting period consisted of dairy farmers and middle and high school students. In addition university students operated the demonstration digester system Changes/Problems:Due to COVID our planned farmer workshops at the extension farm could not take place. Given the economic stress of small dairy farmers investment in farm infrastructure at current milk prices is unlikely. Therefore the likelihood of attracting farmers to attend anaerobic digestion workshops was deemed unrealistic. Our hope is that we will conduct more workshops in the last winter season of the grant What opportunities for training and professional development has the project provided?Approximately 60 High School students participated in a field trip to the learning farm of Cornell Cooperative Extension (CCE) where the digester is located that treats the CCS cafeteria. Students learned about animal care, greenhouse operation, maple syrup production and anaerobic digestion. Due to COVID we did not complete any farmer workshops at the farm showcasing the model system. Over the calender year the we processed approximately 300 kg of Foodwaste generated at the Canton middle and high school in addition to approxiately 200 kg per week of preconsumer foodwaste generated in the CCE kitchen, which was preprocessing locally grown produce for area public schools. How have the results been disseminated to communities of interest?Results have been disseminated through site visits of K-12 students, presentations at conferences/workshops and journal publications What do you plan to do during the next reporting period to accomplish the goals?Continue operating the digester system to generate a more comprehensive data set that can be used for process evaluation. Continue outreach activities to public schools and farmers publish results.

    Impacts
    What was accomplished under these goals? The digester has been in operation througout the year, treating dairy manure in the summer and foodwaste from the Canton public school together with foodwaste generated at the Cornell Cooperative Extension commercial kitchen. On average 500 kg per week of foodwaste was treated during the academic year while an equivalent amount of dairy manure was treated during the summer months. Biogas was used for heating the digester and the seedlings greenhouse in May of each year. Excess biogas was flared. The small digester produced approximately 3 times as much energy as was needed for digester heating.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2021 Citation: Traub, A.; R. Welsh; S. Rogers; S. Grimberg (2021) Small Farms Using Anaerobic Digestion: A Viable Technology Education and Outreach Effort. Agroecology and Sustainable Food Systems, DOI: 10.1080/21683565.2020.1841708
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: Welsh, R., Webb, M.E., Grimberg, S., Rogers, S. (2018). Measuring the results of a workshop on installing anaerobic digesters on smaller livestock farms. Renewable Agriculture and Food Systems, 1-5. doi:10.1017/S1742170518000212
    • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Burdick, J., J. DeWaters, S. Grimberg (2021) Poopy Power: Food to Energy. Submitted to 126th Annual STANYS (Science Teachers Association of New York State, Inc.) Conference, November 5-7, 2021, Rochester, NY.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: DeWaters, J.E., S. J. Grimberg (2021) Food to Energy: A K12/University Partnership to Develop a Resource Recovery Program. In: Proceedings of the 128th Annual ASEE Virtual Conference & Exposition, July 2021. Paper ID #23605.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: DeWaters, J.E., and S.J. Grimberg (2020) Food-to-Energy: How does THAT work? Teaching Students about Waste Disposal Options and the Science of Resource Recovery. A workshop presented at the 2020 ASEE Virtual Annual Conference Experience, Virtual On Line, June 24, 2020.


    Progress 04/15/19 to 04/14/20

    Outputs
    Target Audience:This past year we reached the following target audience: 1. Small farmers: these were primarily reached through the successful completion of three workshops at the Cornell Cooperative Extension Farm in Canton, NY. 2. Producers: In addition to dairy farmers we had a large fraction of our workshop participants include produce producers and menenites. They were primarily interested of how to integrate anaerobic digestion of foodwaste to generate heating or cooking fuel. 3. K12 students: Through the afterschool program at the Cornell Cooperative Extension (CCE) farm we conducted tours for the particpants on the operation of the digester and how to treat foodwaste from the harvest kitchen at the farm. In addition through funding from Constellation Energy the PI was able to bring 200 K12 students to the farm from the Canton public school district educating them about resource recovery technologies applied to foodwaste treatment using anaerobic digestion. Changes/Problems:Given the economic climate for small dairy farmers we expanded the recruiting for our workshops to reach vegetable and fruit producers as well as mennonite farmers. Among these groups of farmers we noticed significant interest in the technology. In addition, it seems that their farm operations may be flexible enough to accomodate anaerobic digestion within their farm structures. We adopted our workshop presentations to especially small system, which was well received. The challenge for the coming year will be to identify relevant examples at the representative small farm scale so we can share economic data of value to the target audience. What opportunities for training and professional development has the project provided?We completed three farmer workshops during the 2018/2019 season. A series of three workshops used farmer-participatory research methodologies to assess attitudes and perceptions of small-scale anaerobic digesters in New York State by smaller scale livestock and crop operations. Results indicate a diverse group of farmers are interested in using anaerobic digester systems. Participants who attended the tour and workshop also increased their level of knowledge and understanding of anaerobic digester systems. Participant discussion revealed a need for more information for AD establishment on small farms including detailed economic data and a greater number of example AD systems. Additionally, results showed improved funding sources for adoption of this sustainable technology will likely increase farmer's rate of adoption. Other training opportunities included the developing of class room activities that were implemented at the Canton Middle and High School. Approximately, 100 students were directly exposed to these lesson plans in 2019. How have the results been disseminated to communities of interest?As a result of the workshops we are also working with a soil and water district close to the finger lakes who has a high number of Mennonite farms. We are evaluating the design of a community type digester for a group of 4-5 farms treating their manure. As these farms are typically arranged in close proximity to eachother and each farm is small (approx. 25 cows) a shared facility would allow for more economic treatment while nutrients and biogas could be used by all farms. What do you plan to do during the next reporting period to accomplish the goals?Through the operation of the integrate manure/foodwaste treatment system we have generated a large amount of data that is being analyzed. The goal for this year will be to disseminate the findings of the continuous operation of the system. We believe we will publish a manuscript summarizing the energy and economic analysis of the foodwaste/manure treatment process, another manuscript on highlighting the fate of pathogens through the system including on recovered bedding material and several conference presentations. Over the winter period we will plan on extending our workshops. This will allow us to generate a larger data set for our assessment tools further allowing us to complete a more in depth analysis. Given our remote loaction we will be offering workshops through the internet hopefully further broadening the impact of this NIFA project. We will continue our outreach activities to K12 students further broading their understanding of these processes. Lastly we will update our website so that continously collected digester performance data will be readiliy accessible to system designers or farmers interested in evaluating the technology.

    Impacts
    What was accomplished under these goals? The system has been operational for 2019. Over the school year we are treating 100 gallons per week of foodwaste generated at the harvest kitchen on the CCE farm, 120 gallons per week of foodwaste generated at the Canton public school dining halls in addition to 400 lbs per week of dairy manure. We are collecting contiuous data of operation of the system, collecting biogas production, methane concentration, temperatures continuously as well as mass loadings during feeding events. In addition we are collecting data on solids recovered, pathogen fate within the digester and on the recovered solids. The data set is currently being used for at least two more publications highlighting the performance of the system. Our workshops have seen steady participation from a range of producers. Most promising given the current economic state of the small dairy producers were organic farmers as well as small businesses focusing on vegetable and fruit production. Both of these areas have high energy demands during harvest season for food processing which could be offset through the use of biogas generated through anaerobic digestion. Our outreach activities have reached several hundred (approximately 300) K12 students in 2019.

    Publications

    • Type: Journal Articles Status: Submitted Year Published: 2020 Citation: Traub, A.; R. Welsh; S. Rogers; S.Grimberg Small Farms Using Anaerobic Digestion: A Viable Technology Education and Outreach Effort. Submitted to Agroecology and Sustainable Food Systems.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Traub, A.; R. Welsh, S. Grimberg, S. Rogers, P. Ames (2019) Participatory Research with Small to Moderate-sized Farmers Enhances Design of, and Interest in, Anaerobic Digester Technology. Presented at the 2019 ASEE Zone 1 Conference, April 11-13, 2019, Niagara Falls, NY.


    Progress 04/15/18 to 04/14/19

    Outputs
    Target Audience:During the reporting period we reached K-12 students participating in extension farm after school and summer programs. In addition we partnered with Canton public school district to educate students in foodwaste resource recovery efforts using our digester to treat foodwaste in addition to dairy manure. Lastly we conducted workshops for area farmers to educate them about anaerobic digestion of foodwaste, agricultural waste and animal manure. Changes/Problems:Given the very low milk price small area farmers are not in the position to invest in digester technology when relying on milk alone. We therefore broadened our stakeholder definition to alll small producers. Dring this year's workshops we had dairy farmers in addition to vegatable and fruit producers. Vegatable and fruit producers were particularly interested in using small digesters to offset propane use during food preservation and using the extra biogas for heating. In addition to these producers we will also connect foodwaste producers with area farmers in the hope to help farmers with high value feedstock for digestion generating more biogas and thus making the systems more economically viable. What opportunities for training and professional development has the project provided?We organized two farmer workshops during the winter 2019. Overall close to 80 people participated in the workshops through the 2018/19 winter. The workshop included an overview of the technology followed by a visit of the digester system. How have the results been disseminated to communities of interest?we presented at a regional conference and included results as well as invitations to the workshops in our extension mailings/websites What do you plan to do during the next reporting period to accomplish the goals?we will continue with more workshops to increase the exposure of the system to a broader audienc. We will also include webinars to minimize travel time for farmers and thus increase participation.

    Impacts
    What was accomplished under these goals? Our system continously treated dairy manure and kitchen waste generated at the extension farm throughout the year. During the school year we treated approximately 500 kg foodwaste per week. During most of the year we treated in addition 100 kg dairy manure per day. Generated biogas was used to heat a seedlings greenhouse during the shoulder season (March/April) and to heat the digester system. Solids from the digester effluent were characterized in terms of pathogen and solids content. Farmer workshops during the beginning of 2019 were received well. Surveys indicated that all participants significantly improved their understanding about anaeorbic digestion and several farmers were interested in assessing the financial viability of such as system for their operation.

    Publications

    • Type: Journal Articles Status: Submitted Year Published: 2019 Citation: Lennox, B; D. H. Hilderbrandt, S.J. Grimberg, S. Rogers; J. Welsh Feasibility of Small Scale Anaerobic Digester to Treat Dairy Waste. Submitted to Transactions of the ASABE
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Traub, A., R. Welsh, S. Grimberg, S. Rogers, P. Ames (2019) Participatory Research with Small to Moderate-sized Farmers Enhances Design of, and Interest in, Anaerobic Digester Technology. Presented at the 2019 ASEE Zone 1 Conference. Niagara Falls, NY. April 11-13, 2019
    • Type: Journal Articles Status: Under Review Year Published: 2019 Citation: Traub, A., R. Welsh, S. Grimberg, S. Rogers, P. Ames. Resource Recovery at Small Farms Using Anaerobic Digestion: A Viable Technology Education and Outreach Effort. Journal of Extension


    Progress 04/15/17 to 04/14/18

    Outputs
    Target Audience:During the past year the focus of the project was to enhance the operation of the digester, connect the digester system to a seedling greenhouse and prepare for the installation of a solids separtion system. The target audience that was reached throught the last year were: 1. high school students participation in the Ag acdemy at the extension farm and building the seedling greenhouse 2. undergraduate students visiting the farm for educational - sustainability tours 3. graduate students working on the installation and assessment of the integrated process. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Four seniors from SUNY canton developed a shredder to reduce particle size of fibrous material as part of their senior design project. The prototype will be sclaed up at Clarkson this summer and implemented at the demonstration plant for operational testing. one undergrduate and one graduate student were trained to operate and improve the system. How have the results been disseminated to communities of interest?Adhoc tours through at the extension farm to middle school, high school students as well as undergraduate students of Saint Lawrence University and SUNY Canton. What do you plan to do during the next reporting period to accomplish the goals?We will integrate the solids separation system into the overall system We will improve the user friendlyness of the data dissemination website We will complete several workshops to area farmers and producers to determine their perception to the overall system we will determine operational efficiency of the system as well the the potential to integrate the feedstocks into the circular farm economy

    Impacts
    What was accomplished under these goals? Integrate the anaerobic digester with the CCES-SLC greenhouse and commercial kitchen to demonstrate a waste to energy loop that can improve energy and nutrient cycles. The green house heating was integrated with the digester system. Using biogas an on-demand water heater provides the heat for hydronic heating of the seedling greenhouse. Support tables were constructed by high school students. Graduate students built six radiant heating blocks using concrete that were installed on the tables. Heat to the modules and be individually regulated. Improve AD process monitoring and link both measured and continuous digester data to the web so it can be used nationwide as a data set to assess small digester performance A website has been developped that allows for downloading of all raw data collected from the operation of the digester system. That data can be used by developers and model developers to verify model performance and compare the operation of this system to otheres. The website link is :http://stlawrence.cce.cornell.edu/-energy Integrate a solids recovery system into the digester and monitor and assess digested solids properties for beneficial reuse (e.g., as bedding) Solid separtor has been ordered and will be installed by mid June. This will allow for data collection on solids quality and quantity to assess reuse. Develop tools to assess farmer perception of integrated closed loop AD systems to be used pre- and post- extension outreach modules. Workshops are being prepared for Winter 2018. A survey document to assess farmer perception has been developed and workshops will be scheduled for the coming winter season after the complete system has been in operation for more than 6 months and data has been available to assess both environmental and economic benefits.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2018 Citation: Welsh, R., Webb, M., Grimberg, S., Rogers, S. (2018). Measuring the results of a workshop on installing anaerobic digesters on smaller livestock farms. Renewable Agriculture and Food Systems, 1-5. doi:10.1017/S1742170518000212
    • Type: Journal Articles Status: Submitted Year Published: 2018 Citation: Lennox, B; D. H. Hilderbrandt, S.J. Grimberg, S. Rogers; J. . Welsh Feasibility of Small Scale Anaerobic Digester to Treat Dairy Waste. Submitted to Transactions of the ASABE