This webinar explores where, how, and when it makes sense to merge manure digesters with natural gas pipelines. The webinar shares national, project specific and farm-level perspectives. This presentation was originally broadcast on April 16, 2021. Continue reading “Coupling Manure Digesters with Renewable Natural Gas Systems”
Thermal and Electrical Energy and Water Consumption in a Midwest Dairy Parlor
The typical dairy farm uses a large amount of energy during milking activities. This is due to the frequency of milking and the energy intensive nature of harvesting milk, keeping it cool, and cleaning the equipment with hot water. Renewable energy systems generally become more economically efficient as the amount of energy used increases, making dairy farms a great place to incorporate renewable energy.
Dairy farms have not typically been set up with energy efficiency in mind and often use relatively expensive fuel sources like heating oil or propane to heat water. One of the difficulties encountered with renewable energy systems is the intermittent generation of wind and solar energy, whereas the energy load on a dairy farm is very consistent since cows are typically milked twice or three times every day (very large dairies may milk continuously). An efficient way to store energy has long been sought to tie energy production and consumption together. A dairy farm’s need for both electricity and heat provides an ideal situation to generate electrical energy on-site to meet current electrical load requirements, displace conventional thermal fuels with electrical energy, and evaluate thermal storage as a solution to the time shifting of wind and solar electrical generation.
What did we do?
The dairy operation at the University of Minnesota West Central Research and Outreach Center in Morris milks between 200 and 275 cows twice daily and is representative of a mid-size Minnesota dairy farm. The cows are split almost evenly between a conventional and a certified organic grazing herd, and all cows spend the winter outside in lots near the milking parlor. The existing dairy equipment is typical for similarly sized dairy farms and includes none of the commonly recommended energy efficiency enhancements such as a plate cooler, refrigeration heat recovery, or variable frequency drives for pump motors. The WCROC dairy provides an ideal testing opportunity to evaluate and demonstrate the effect of on-site renewable energy generation and energy efficient upgrades on fossil fuel consumption and greenhouse gas emissions (Figure 1).
A data logger was installed in the utility room of the milking parlor in August 2013 to monitor 18 individual electric loads, 12 water flow rates, 13 water temperatures, and two air temperatures. Average values were recorded every 10 minutes for the last 4 years. The milking parlor has gas and electric meters that measure the total consumption of natural gas and electricity within the parlor. The data helped us evaluate energy and water usage of various milking appliances. Some small energy loads were not measured in unused parts of the barn, or for equipment not directly related to the milking operation. These small and miscellaneous loads were estimated by subtracting monitored energy use from the total energy use.
Baseline measurements were collected at the WCROC dairy and overall, the milking parlor currently consumes about 250 to 400 kWh in electricity and uses between 1,300 and 1,500 gallons of water per day (Figures 2 and 3). The parlor currently uses about 110,000 kWh per year (440 kWh per cow per day) in electricity and 4,500 therms per year in natural gas. A majority of the electricity (26 percent) is used for cooling milk , with ventilation, fans and heaters utilizing 16 percent. The dairy uses about 600 gallons of hot water per day, with a majority used for cleaning and sanitizing milking equipment (57%), followed closely by cleaning the milking parlor (27%). Energy and water usage fluctuates throughout the year; the dairy calves 40 percent of the cows from September to December and 60 percent from March to May. Therefore, water and energy use escalates dramatically during April.
The first energy efficiency upgrade was the installation of a variable frequency drive for the vacuum pump in September 2013. Prior to the upgrade, the vacuum pump used 55 to 65 kWh per day. Following installation, electrical consumption by the vacuum pump decreased by 75% to just 12 kWh per day. This data provides a vivid example of the significant energy savings that can be achieved with relatively simple upgrades.
Because the dairy operates both organic and conventional systems, two bulk tank compressors are used: one scroll and one reciprocating. The scroll compressor is the newest and uses 15 kWh per day versus 40 kWh per day for the reciprocating compressor. Based on milk production, the scroll compressor costs $0.73 per kWh per cwt. versus $1.08 per kWh per cwt. for the reciprocating compressor, indicating that the scroll compressor is more efficient. In terms of fossil fuel consumption, milk harvesting consumed more energy than feeding and maintenance.
During the fall of 2016, a TenKSolar Reflect XTG 50 kW DC array was installed. The annual production from this solar PV system was projected to be 70,000 kWh. At a total cost of $138,000 ($2.77/W) for the solar system, a 19.7-year simple payback without incentives was predicted. Adding the “Made in Minnesota” incentives would reduce the payback period to 8.6 years.
In 2017, two 10-kW VT10 wind turbines from Ventera were installed. These turbines are a three blade, downwind turbine model, each with an annual predicted generation of 22,400 kWh. The wind system cost was $156,800 ($78,400 per tower) with a 35-year simple payback without incentives. With the 30% federal credit, each turbine would have a 24.5-year payback.
What we have learned?
Our study suggests that fossil energy use per unit of milk could be greatly reduced by replacing older equipment with new, more efficient technology or substituting renewable sources of energy into the milk harvesting process. To improve energy efficiency, begin with an audit to gather data and identify energy-saving opportunities. Some energy efficiency options that may be installed on dairy farms include refrigeration heat recovery, variable frequency drives, plate coolers, and more efficient lighting and fans. A majority of these upgrades have immediate to two- to five-year paybacks. Make all electrical loads as efficient as possible, yet practical. Consider converting all thermal loads to electricity by the use of heat pumps that allow for cooling of milk. In the future, we have plans to harvest energy from our manure lagoon and store electricity as heat by use of heat pumps. Renewable energy options also can improve energy efficiency.
Future Plans
We will continue to monitor the WCROC dairy and make renewable energy upgrades. We have begun monitoring the two 10-kW wind turbines, and installed a new 30-kW solar array in the WCROC pastures for renewable energy production. Additionally, we will evaluate the cow cooling potential of solar systems in the grazing dairy system at the WCROC. This study is the first step toward converting fossil fuel-based vehicles used in dairy farms to clean and locally produced energy. The knowledge and information generated will be disseminated to agricultural producers, energy professionals, students, and other stakeholders.
Authors
Brad Heins, Associate Professor, Dairy Management, hein0106@umn.edu
Mike Reese, Director of Renewable Energy
Eric Buchanan, Renewable Energy Scientist
Mickey Cotter, Renewable Energy Junior Scientist
Kirsten Sharpe, Research Assistant, Dairy Management
Additional information
We have developed a Dairy Energy Efficiency Decision Tool to help provide producers a quick way to estimate possible energy and costs savings from equipment efficiency upgrades. The tool can be used to quickly see what areas of a dairy operation may provide the best return on investment. Furthermore, we have developed a U of MN Guidebook for Optimizing Energy Systems for Midwest Dairy Production. This guidebook provides additional information about the topics that were discussed in this article, as well as the decision tool. More information may be found at https://wcroc.cfans.umn.edu/energy-dairy
Acknowledgements
To complete our goals, we have secured grants from the University of Minnesota Initiative for Renewable Energy and the Environment (IREE), the Minnesota Rapid Agricultural Response Fund, and the Xcel Energy RDF Fund.
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.
Small to Mid-Sized Dairies: Making Compact Anaerobic Digestion Feasible
Why Consider Small or Medium Digester Projects?
Anaerobic digestion (AD) is an environmentally-friendly manure management process that can generate renewable energy and heat, mitigate odors, and create sustainable by-products such as bedding or fertilizer for dairies and farmers. However, due to economics, a majority of commercially available AD technologies have been implemented on large farming operations. Since the average herd size of dairies across the country is below 200 head of milking cows, there is a need for small-scale AD systems to serve this market.
What did we do?
The University of Wisconsin-Oshkosh, in collaboration with BIOFerm™ Energy Systems, installed the EUCOlino—a small-scale, mixed, plug-flow digester—onto on a 136 milking head Wisconsin Dairy. The system is pre-manufactured, containerized and requires very limited on-site construction. This includes grading, pouring a concrete pad for the containers and electrical services installation.
Start-up and commissioning were performed after the delivery of the 64 kWe combined heat and power (CHP). The input materials consist of bedded-pack dairy manure (corn or bean stover and straw), parlor wash water, and minor additional substrates such as lactose or fats, oils, and grease.
Solid materials are dumped via bucket tractor into a hopper feeder system that uses an auger to feed substrate into the anaerobic digestion tank. Additional parlor water is piped directly into the anaerobic digestion tank and mixed with the solids to make a feedstock of approximately 13% total solids. The solids are fed hourly, which is controlled by the PLC system.
The digester has a ~30-day retention time and the biogas produced is stored in a bag above the fermenters. Biogas produced is conditioned and combusted in a CHP mounted on a separate skid. Effluent from the system is pumped directly to an open pit lagoon for storage and subsequently land applied as fertilizer. The system produces approximately 25 – 33 m3/hour of biogas, with a raw biogas quality of 52-60% CH4 and less than 700 ppm H2S.
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 |
 |
What have we learned?
This project has been an important step forward in developing future small-scale anaerobic digesters across the U.S. Notably, our installation has given us insight into balancing system economics with the size of small-scale models; the energy output of the system must exceed pre-processing energy requirements and the digester must still be large enough for the designed residence time. Our experience has shown that, while reducing the size of a digester, these requirements remain essential for an installation to economically make sense.
Additionally, challenges involved in AD at the small-scale are related to pre-processing or feedstock conveyance. Once suitable consistence or size for conveyance, anaerobically digesting the organic fraction can be relatively easy. Inconsistency of incoming feedstocks is very detrimental to the system’s stability. Additionally, exterior feedstock storage and above ground piping can limit processing potential when severe cold weather settles in. While all of these are challenges that are easily overcome with engineering, they come at a cost and that can make or break the economics at this scale.
Future Plans
For the small-scale EUCOlino to be effective in the United States, it is key to establishing a U.S.- based manufacturing location. Pre-processing needs to be well-suited to the incoming feedstock. Post-digestion products need established off-takers, for electricity generation, bedding, fertilizer, etc.
Authors
Steven Sell, Manager Application Engineer, BIOFerm™ Energy Systems beaw@biofermenergy.com
Whitney Beadle, Marketing Communications, BIOFerm™ Energy Systems
Additional information
The following publications offer additional information on the Allen Farms digester:
- American Dairymen: BIOFerm Energy Systems Offers Dairy Producers Cutting Edge Digestion Biogas Technology
- Progressive Dairymen: Oshkosh Paves Way for Small-Scale Digester Projects
- BioCycle: Modular Dairy Digester
- North American Clean Energy: Energy Systems & Allen Farms Awarded Grant to Fund Feasibility Study
- University of Wisconsin-Oshkosh: University of Wisconsin Oshkosh—Titan 64 (Small Farm Biogas System—EUCOlino)
Readers interested in this topic can also visit our website for more information on the Allen Farms digester and other BIOFerm projects. We can also be found on Facebook, Twitter, and LinkedIn.
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.
The Great Biogas Gusher
Why Pursue Bio-Energy?
The great Texas Oil Boom, also referred to as the Gusher Age, provided for dramatic economic growth in the US in the early 20th century, and ushered in rapid development and industrial growth. Although we typically think of the Middle East when we consider the impacts of oil discoveries on local economies (reference Dubai), at the time of its discovery, the oil finds in Texas were unprecedented; and the US quickly became the world’s top producer of petroleum.
As we all know, the rest of the world came to the party, and the US was soon falling in the ranks of top petroleum producers. Though the US oil reserves are vast, increasing concerns over the environmental impacts of finding, mining, extracting, refining, and consuming fossil fuels has incentivized the development of renewable energy resources, such as solar, wind, hydro, and bioenergy. Of these forms of renewable energy, bioenergy holds the promise for replacement of fossil fuels for transportation use.
What did we do?
Bioenergy may be described as fuels derived from organic materials, such as agricultural wastes, through processes like anaerobic digestion. The US has even more organic resources above the Earth’s surface than are identified in the petroleum and natural gas deposits yet to be exploited, yet the development of agricultural bioenergy systems seems to be progressing at a snail’s pace, as compare to the great Oil Boom. There is enormous potential in producing biogas from agricultural, industrial, municipal solid waste, sewage and animal byproducts which can be used to fuel vehicles. The EPA estimates that 8,200 US dairy and swine operation could support biogas recovery systems, as well as some poultry operations. Biogas can be collected from landfills and used to power natural gas vehicles or to produce energy. Wastewater treatment plants are estimated by the EPA to have the potential of about 1 cubic foot of digester gas per 100 gallons of wastewater, this energy could potentially meet 12% of the US electricity demand. Industrial, commercial and institutional facilities provide another source of biogas, in particular supermarkets, restaurants, and educational facilities with food spoilage.
What have we learned?
This presentation compares and contrasts the historical development of fossil fuel reserves with the potential for development of bioenergy from agricultural sources, such as animal wastes and crop residues. The US energy potential from these sources is grossly quantified, and current development inhibitions are identified and discussed. Opportunities for gathering biogas and bioenergy from multiple regional sources, similar to the processes used in the Texas oil fields, are discussed. The presentation offers insight into overcoming these obstacles, and how the US may once again rise to the top of the energy development rankings through efficient use and stewardship of our organic resources.
Future Plans
Biogas and bioenergy resources present an enormous opportunity for renewable energy development, and progression toward energy independence for the U.S. The U.S. currently has more than 2,000 active biogas harvesting sites, but claims more than 11,000 additional sites can be developed in the U.S., with the potential to power more than 3 million American homes if used to fuel electricity generating power plants. The USDA, EPA and DOE recently created a US Biogas Opportunities Roadmap which is off to a good start, which hopefully will initiate biogas programs, and foster investment in biogas systems to improve the market vitality in each state. To move the process forward, policy-makers, investors and the public need to have improved collaboration and communication on the state level. We need to develop a clear plan and strategy for developing these valuable biogas resources to promote environmental sustainability and economic growth of our b ioenergy sector.
Author
Gus Simmons, P.E., Director of Bioenergy, Cavanaugh & Associates, P.A. gus.simmons@cavanaughsolutions.com
Additional Information
http://www.cavanaughsolutions.com 1-877-557-8924
http://www.epa.gov/climatechange/Downloads/Biogas-Roadmap.pdf
Acknowledgements
USDA/DOE/EPA US Bioenergy Roadmap
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.
Thermal-Chemical Conversion of Animal Manures – Another Tool for the Toolbox
How Can Thermo-Chemical Technologies Assist in Nutrient Management?
Livestock operations continue to expand and concentrate in certain parts of the country. This has created regional “hot spot” areas in which excess nutrients, particularly phosphorus, are produced. This nutrient issue has resulted in water quality concerns across the country and even lead to the necessity of a “watershed diet” for the Chesapeake Bay Watershed. To help address this nutrient concern some livestock producers are looking to manure gasification and other thermo-chemical processes. There are several thermo-chemical conversion configurations, and the one chosen for a particular livestock operation is dependent on the desired application and final by-products. Through these thermo-chemical processes manure 
volumes are significantly reduced. With the nutrients being concentrated, they are more easily handled and can be transported from areas of high nutrient loads to regions of low nutrient loads at a lower cost. This practice can also help to reduce the on-farm energy costs by providing supplemental energy and/or heat. Additional benefits include pathogen destruction and odor reduction. This presentation will provide an overview of several Conservation Innovation Grants (CIG) and other manure thermo-chemical conversion projects that are being demonstrated and/or in commercial operation. Information will cover nutrient fate, emission studies, by-product applications along with some of the positives and negatives related to thermo-chemical conversion systems.
What did we do?
Several farm-scale manure-to-energy demonstration projects are underway within the Chesapeake Bay Watershed. Many of these receive funding through the USDA-NRCS Conservation Innovation Grant program. These projects, located on poultry farms, are being evaluated for the performance of on-farm thermal conversion technologies. Monitoring data is being collected for each project which includes: technical performance, operation and maintenance, air emissions, and by-product uses and potential markets. Performance of manure gasification systems for non-poultry operations have also been reviewed and evaluated. A clearinghouse website for thermal manure-to-energy processes has been developed.
What have we learned?
The projects have shown that poultry litter can be used as a fuel source, but operation and maintenance issues can impact the performance and longevity of a thermal conversion system. These systems are still in the early stages of commercialization and modifications are likely as lessons are learned. Preliminary air emission data shows that most of the nitrogen in the poultry litter is converted to a non-reactive form. The other primary nutrients, phosphorus and potassium, are preserved in the ash or biochar co-products. Plant availability of nutrients in the ash or biochar varies between the different thermal conversion processes and ranges from 80 to 100 percent. The significant volume reduction and nutrient concentration show that thermal conversion processes can be effective in reducing water quality issues by lowering transportation and land application costs of excess manure phosphorus.
Future Plans
Monitoring will continue for the existing demonstration projects. Based on the lessons learned, additional demonstration sites will be pursued. As more manure-to-energy systems come on-line the clearinghouse will be updated. Based on data collected, NRCS conservation practice standards will be generated or updated as necessary.
Author
Jeffrey P. Porter, PE, Manure Management Team Leader, USDA-Natural Resources Conservation Service jeffrey.porter@gnb.usda.gov
Additional information
Thermal manure-to-energy clearinghouse website: http://lpelc.org/thermal-manure-to-energy-systems-for-farms/
Environmental Finance Center review of financing options for on-farm manure-to-energy including cost share funding contact information in the Chesapeake Bay region: http://efc.umd.edu/assets/m2e_ft_9-11-12_edited.pdf
Sustainable Chesapeake: http://www.susches.org
Farm Pilot Project Coordination: http://www.fppcinc.org
National Fish and Wildlife Foundation, Chesapeake Bay Stewardship Fund: http://www.nfwf.org/chesapeake/Pages/home.aspx
Acknowledgements
National Fish and Wildlife Foundation, Chesapeake Bay Funders Network, Farm Pilot Project Coordination, Inc., Sustainable Chesapeake, Flintrock Farm, Mark Weaver Farm, Mark Rohrer Farm, Riverview Farm, Wayne Combustion, Enginuity Energy, Coaltec Energy, Agricultural Waste Solutions, University of Maryland Center for Environmental Science, Environmental Finance Center, Virginia Cooperative Extension, Lancaster County Conservation District, Virginia Tech Eastern Shore Agricultural Research and Extension Center, Eastern Shore Resource Conservation and Development Council, with funding from the USDA Conservation Innovation Grant Program and the U.S. EPA Innovative Nutrient and Sediment Reduction Program.
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.
Evaluation of a Continuously-Mixed Farm-Based Anaerobic Co-Digestion System Following the U.S. EPA Protocol for Quantifying and Reporting on the Performance of Anaerobic Digestion Systems for Livestock Manures – Final Project Results
This paper compliments another paper proposed for this conference “Lifecycle analysis of greenhouse gas (GHG) emissions from a New York State dairy farm anaerobically co-digesting manure and food waste.”
Purpose
New York State’s largest manure-based anaerobic co-digestion facility was evaluated continuously for a 2-year period following the U.S. EPA Protocol for quantifying and reporting on the performance of anaerobic digestion systems for livestock manures. Overall, we assessed and determined the system’s performance with respect to the: 1) conversion of biomass to biogas, 2) conversion of biogas to useful energy, and 3) system’s economics. The information developed by this project can be used to compare performance information developed from other manure-based anaerobic digestion systems. Related: Treatment Technologies for Livestock Manure
What did we do?
After initial system evaluation and monitoring plan development, the farm was visited monthly for 24 months to collect data. In addition to the digester influent and effluent samples taken during each monthly sampling date, on-site measurements were taken and data were manually recorded from equipment and plant logs. A particularly important log, were the imported feedstocks brought on-site for inclusion to the AD. This log recorded the date and time feedstock was delivered, the type of feedstock, and the volume delivered. The specific data collected/measured are shown in Table 1.
Table 1. Data collected/measured on-site at each sampling date.
| Item |
|---|
| 1. Date and time of readings |
| 2. Methane (CH4), Carbon dioxide (CO2), Oxygen (O2), and Hydrogen sulfide (H2S) concentrations in biogas after digester |
| 3. CH4, CO2, O2, and H2S concentrations in biogas after bio-scrubber |
| 4. Engine-generator set run time |
| 5. Cumulative electricity purchased and sold |
| 6. Daily animal populations since previous sampling event |
| 7. Logs of imported feedstocks |
| 8. Problems occurred during period |
Further, data (Table 2) from the system’s supervisory, control, and data acquisition (SCADA) unit were downloaded, compiled and analyzed for each period. SCADA data were generated from an array of sensors and meters originally installed by the company that designed and built the digester, i.e., Bigadan A/S.
Table 2. Data obtained from the SCADA system for each period.
|
Parameter |
|---|
| 1. Total influent to pasteurization |
| 2. Food waste to pasteurization |
| 3. Manure to pasteurization |
| 4. Biomass from pasteurization to digester |
| 5. Effluent digester to storage tank |
| 6. Biogas production digester |
| 7. Biogas to generator |
| 8. Generator electrical energy output |
| 9. Generator thermal energy recovered |
| 10. Digester vessel upper temperature |
| 11. Digester vessel lower temperature |
Overall, digester influent and effluent samples were collected with the goal of obtaining representative samples. To do this, grab samples were collected directly from both the digester influent and effluent lines over a period of approximately 30 min during a pumping sequence, to develop a 5-gallon composite, master-sample. The entire volume of this sample was then agitated using a paint mixer powered by a portable electric drill until visibly determined to be homogenized. A 1-liter composite sample was immediately taken and stored on ice, and subsequently frozen before being sent for laboratory analysis. Samples were taken in this fashion approximately every 30 days over the 24-month monitoring period. Additionally, samples coming from the raw manure receiving tank and from the combined imported feedstocks tank were also obtained for two sampling dates at the beginning of the monitoring project to characterize the individual influent streams to the digester.
All samples collected during the 24-month monitoring period were sent for analysis to Certified Environmental Services’ (CES) laboratory in Syracuse, NY, approved by the New York State Department of Health, Environmental Laboratory Approval Program (NYSDOH-ELAP #11246). All samples were analyzed in triplicate for: total solids (TS), total volatile solids (VS), chemical oxygen demand (COD), pH, and total volatile acids as acetic acid (TVFA). In addition, the following nutrients were determined in triplicate: total phosphorus (TP), ortho-phosphorus (OP), total Kjeldahl nitrogen (TKN), ammonia-nitrogen (NH3-N) and potassium (K). CES followed the appropriate testing methods outlined in Table 3 for each parameter measured.
Table 3. Standard analytical methods used by CES laboratory for sample analyses.
| Parameter | Standard |
|---|---|
| Total Solids (TS) | EPA 160.3 |
| Total Volatile Solids (VS) | EPA 160.4 |
| Fixed Solids (FS) | EPA 160.4 |
| Volatile Acid as Acetic Acid (TVFA) | SM18 5560C |
| Chemical Oxygen Demand (COD) | SM18 5220B |
| pH | SW846 9045 |
| Total Kjeldahl Nitrogen (TKN) | EPA 351.4 |
| Ammonia-Nitrogen (NH3-N) | SM18 4500F |
| Organic-Nitrogen (ON) | By subtraction: TKN – NH3-N |
| Total Phosphorous (TP) | EPA 365.3 |
| Ortho Phosphorous (OP) | EPA 365.3 |
| Total Potassium (K) | EPA SW 846 6010 |
Methane (CH4), carbon dioxide (CO2), hydrogen sulfide (H2S), and oxygen (O2) concentration in biogas, were measured on-site during monthly visits using a Multitec 540 (Sewerin GmbH, Germany), a portable hand-held gas measuring device equipped with infra-red/electrochemical sensors.
What have we learned?
For the entire monitoring project, an average of 1,891±62 lactating cows per day from Synergy Dairy contributed manure to the digester. The average daily loading rate of the digester was 80,408±19,266 gal, where the average percent of imported waste (mostly food-grade residues) co-digested with manure was 25±6% on a volume-to-volume (v/v) basis. The average reduction of organic matter thru the monitoring project was 42% with respect to the influent, while 75% of the odor-causing volatile fatty acids were reduced. In comparison, a previous monitoring study reported by the authors in five manure-based co-digestion operations showed a reduction in organic matter and volatile acids between 36% and 53% and 85% and 91%, respectively. The average daily digester biogas production for the entire monitoring project was 495±78 ft3 per 1,000 lbs of total influent added to the digester, or 173±34 ft3 per cow contribut ing to the digester. The engine-generator set produced an average of 23±7 MWh of electricity per day, from which the average daily parasitic load of the AD system was 3±1 MWh, accounting for approximately 14% of the electricity generated by the plant. Overall, the average capacity factor and online efficiency of the anaerobic digester system during the entire monitoring project were 0.66±0.22 and 80±23%, respectively. The electrical energy generated translated into an overall thermal conversion efficiency of 42±4%. Also, an additional 13±5% of the total energy in the biogas was recovered by the engine as hot water. Thus, an overall 55% (electrical + thermal) of the total energy contained in the input biogas was recovered by the engine-generator set during the monitoring project.
The majority of the challenges experienced by the Synergy AD system were of mechanical origin, whereas 20% were related to the biological process; only 8% of the downtime was due to scheduled systems maintenance. Some of the problems were related to the extreme cold conditions experienced in the Northeast during the period from December 2013 to February 2014. According to NOAA’s National Climatic Data Center, this period was the 34th coldest for the contiguous 48 states since modern records began in 1895, with an average temperature of 31.3F, 1.0F below the 20th century average (NOAA, 2014).
Future Plans
This manure-based anaerobic digester is the 8th New York State digester we have extensively monitored and reported on. Near-term future planned work includes monitoring a lower cost horizontal plug flow digester on a 2,000-cow farm. This digester uses high density polyethylene (HDPE) material heat welded together as the digester vessel.
Authors
Curt Gooch, Senior Extension Associate, Cornell PRO-DAIRY Program cag26@cornell.edu
Rodrigo Labatut
Additional information
A full report, written for the project sponsor, can be found on the Cornell PRO-DAIRY dairy environmental systems website, https://prodairy.cals.cornell.edu/environmental-systems/.
Acknowledgements
First and foremost, we wish to thank the Synergy Dairy Farm, Synergy Biogas, and CH4 Biogas for their collaborative efforts that made this project possible. We also like to thank the project sponsor, the Wyoming County (New York) Industrial Development Agency.
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.
Feasible Small-Scale Anaerobic Digestion – Case Study of EUCOlino Digestion System.
| * Presentation slides are available at the bottom of the page. |
Waste to Worth home | More proceedings….
Abstract
While large-scale farms have typically been the focus of anaerobic digestion systems in the U.S., an emerging need has been identified to serve smaller farms with between 50 and 500 head of cattle. Implementing such a small, standardized, all-in-one system for these small farm applications has been developed. Small-scale digesters open the playing field for on-farm sustainability and waste management.
Unloading the first biodigester unit. |
This presentation on small-scale digestion would discuss the inputs, processing, function, and outputs of BIOFerm™ Energy Systems’ small agitated plug flow digester (EUCOlino). This plug-and-play digester system has the ability to operate on dairy manure, bedding material, food waste, or other organic feedstocks with a combined total solids content of 15-20%. A case study would be presented that describes the site components needed, the feedstock amount and energy production, as well as biogas end use. Additional details would include farm logistics, potential sources of funding, installation, operation, and overall impact of the project.
This type of presentation would fill an information gap BIOFerm™ has discovered among dairy farmers who believe anaerobic digestion isn’t feasible on a smaller scale. It would provide farmers who attend with an understanding of the technology, how it could work on their specific farm and hopefully reveal to them what their “waste is worth”.
Why Study Small-Scale Anaerobic Digestion
To inform and educate attendees about small-scale anaerobic digestion surrounding the installation and feasibility of the containerized, paddle-mixed plug flow EUCOlino system on a small dairy farm <150 head.
Biodigester unit being installed at Allen Farms. |
What Did We Do?
Steps taken to assist in financing the digestion system include receiving grants from the State Energy Office and Wisconsin Focus on Energy. Digester installation includes components such as feed hopper, two fermenter containers, motors, combined heat and power unit, electrical services, etc…
What Have We Learned?
Challenges associated with small project implementation regarding coordination, interconnection, and utility arrangements.
Future Plans
Finalize commissioning phases and optimize operation.
Authors
Amber Blythe, Application Engineer, BIOFerm™ Energy Systems blya@biofermenergy.com
Steven Sell, Biologist/Application Engineer, BIOFerm™ Energy Systems
Gabriella Huerta, Marketing Specialist, BIOFerm™ Energy Systems
Additional Information
Readers interested in this topic can visit www.biofermenergy.com and for more information on our plants, services and project updates please visit us on our website at www.biofermenergy.com. You will also see frequent updates from us in industry magazines (BioCycle, REW Magazine, Waste Age). BIOFerm will also be present at every major industry conference or tradeshow including the Waste Expo, Waste-to-Worth and BioCycle– stop by our booth and speak with one of our highly trained engineers for further information.
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
Feasibility of Installation of Anaerobic Digesters at Cattle Operations and Demonstration of a Decision Support Tool
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Abstract
An online decision support tool for determining feasibility of anaerobic digestion has been developed (http://www.erams.info/AD_feasibility/). This decision support tool is specifically targeted to cattle operations in the arid west and provides general information on anaerobic digestion (AD), recommendations on the technical and economic feasibility of AD based on producer provided information on management practices, recommendations on appropriate AD technology based on user defined criteria for the system, guidance on technology provider selection, and required maintenance for operation of an AD system. The goal of the tool is to enable and empower producers to make informed decisions about AD based on unbiased information rather than relying on the biased information often provided by technology providers. In this workshop, the drivers for technical and economic feasibility for on farm AD installation will be discussed and the online decision support tool will be demonstrated.
Why Look at Anaerobic Digestion for Cattle Operations?
Anaerobic digestion is a waste management tool with many advantages, including generation of energy for on-site use. However, careful consideration must be given regarding technical and economic feasibility for installation on cattle operations. A web-based decision tool has been developed to provide technical and economic guidance to producers on feasibility of on-farm anaerobic digestion (http://www.eramsinfo.com/erams_beta/AD_feasibility/).
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Home Page of Web-based Decision Support Tool |
What Did We Do?
Based on commonalities found from feasibility studies conducted throughout the state of Colorado, a web-based decision tool has been developed to provide technical and economic guidance to producers on feasibility of on-farm anaerobic digestion (http://www.eramsinfo.com/erams_beta/AD_feasibility/)
What Have We Learned?
For use of conventional anaerobic digestion technology at dairy facilities, manure should be collected on concrete by scraping or flushing. Anaerobic digestion of manure collected on dry lots is not feasible with conventional technology. Economics are favorable when on-site energy use is high and the energy produced by the digester is primarily used on-site.
Future Plans
We will continue to develop and improve the existing web-based tool. We are also working on developing an anaerobic digestion technology suitable for dry lot collected manure.
Authors
Sybil Sharvelle, Assitant Professor, Colorado State University, Department of Civil and Environmental Engineering, sybil.sharvelle@colostate.edu
Jeffrey Lasker, Research Assistant, Colorado State University
Lucas Loetscher, Research Assistant, Colorado Sate University
Additional Information
http://www.eramsinfo.com/erams_beta/AD_feasibility/
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
Next Generation Technology Swine Waste-to-Energy Project
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Abstract
| * Presentation slides are available at the bottom of the page. |
The Loyd Ray Farms project is the first swine waste project in the State of North Carolina to generate and transfer renewable energy credits (RECs) to a public utility. Utilizing an anaerobic digester as primary treatment, this waste treatment system is designed to meet the Environmental Performance Standards set forth by NC law for new and expanded swine facilities through the use of nitrification/denitrification and further treatment. The system implemented at this farm utilizes anaerobic digester technology to turn raw animal waste into biogas. The biogas is used to fuel a microturbine, generating electricity to power the environmental treatment system, and about half of the farm. Related: Manure value & economics
The farm is a finishing swine operation that houses approximately 9,000 pigs near Yadkinville, NC. The concept for this approach was conceived by the team in 2006, followed by economic and performance modeling, permitting, and construction of the commercial-scale system. The project was commissioned on May 27, 2011. Funding for construction was provided by Duke Energy and Duke University, with support from USDA-NRCS and the NC Division of Soil and Water Conservation. Google provides operational funding support in exchange for a portion of the carbon offsets created.
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Loyd Ray Farms is the only innovative Swine waste system in North Carolina that generates Renewable Energy Credits for an electric utility, which generates enough power for the treatment system and has enough surplus electricity to power about half of the farm. Cavanaugh collaborated in this study with Duke University, Duke Energy, and Google with funding from NC Soil & Water Conservation and USDA/Natural Resources Conservation Service. Forefront: Tatjana Vujic of Duke University views the meter readings |
The project began as a conversation about greenhouse gas emissions, sources for renewable energy, and sustaining the state’s swine industry among Duke Energy, Duke University, Google, and Cavanaugh. That conversation led to a project that is getting attention around the world, for its successes in combining strategies to address the concerns for generating renewable energy from agricultural sources, sustaining agriculture, and addressing farming’s relationship to climate change.
The system’s goals: generating about 500 megawatt-hours of electricity annually, reducing greenhouse gas emissions equivalent to 5,000 tons of carbon dioxide annually, reducing ammonia and odor emissions from the farm, and improving the quality of treated wastewater on the farm.”
Is Manure to Energy Important?
We will discuss the successes and challenges in partnered efforts by farmers, electric utilities, and other stakeholders in the marrying of renewable energy generation with enhanced environmental treatment and green house gas emissions reduction, including the economics of such effort.
What Did We Do?
Waste generated by the animals is flushed into an anaerobic digester where bacteria consume the waste and respire energy-rich biogas. The biogas fuels a microturbine that generates electricity, and excess gas is flared. After digestion, the liquid waste is further treated to achieve the Environmental performance Standards set forth by North Carolina for Innovative Swine Waste Treatment Systems. |
The process by which the stakeholders came together in a partnership, the technologies and approaches selected, and the successes/challenges that can be gleaned for advancing future projects. The Loyd Ray Farms project is the first Swine Waste-to-Energy project in the State of North Carolina to place RECs on the North Carolina Utilities Commission REC Tracking System, and is the first swine farm in North Carolina to transfer RECs to Duke Energy. Coupling techniques to improve the environmental treatment system employed at the farm, the Loyd Ray Farm project is also the first ‘Innovative Swine Waste Treatment System’ permitted that utilizes an anaerobic digester as a primary form of waste treatment.
Presenters
William G. “Gus” Simmons, Jr., P.E. Cavanaugh & Associates, P.A., gus.simmons@cavanaughsolutions.com
Gus Simmons, lead designer, M. Steve Cavanaugh, Jr., and Marvin Cavanaugh, Sr. during the commissioning of the system. Cavanaugh developed the concept for Duke University in an effort to create a cost-effective solution that converts swine waste into renewable energy while achieveing a superior level of waste treatment and a reduction in the carbon footprint created by the conventional waste management system. |
Gus Simmons, P.E., is the Director of Engineering at Cavanaugh & Associates, a consulting firm specializing in stewardship through innovation. An NC State University graduate with a BS in Biological & Agricultural Engineering, Gus has worked for a major agricultural producer where he was Director of Environmental Affairs and Engineering Services, managing engineering and construction for facilities in the US and Europe. Gus has designed, permitted, and managed over 5,000 acres of wastewater irrigation in NC, and thousand of acres of wastewater irrigation in the Western US. He has assisted many municipalities and private entitites with the development and implementation of reclaimed water systems and reuse irrigation systems, and has actively participated in alternative wastewater management strategies for the NC Pork Industry. His recent sucessess include the engineering design of an anaerobic digester for animal waste to energy project in Yadkinville, NC which has gained world-wide recognition for its successes in generating RECs and greenhouse gas credits.
Additional Information
- www.cavanaughsolutions.com
- www.pigpower.net
- http://triad.news14.com/content/top_stories/648807/pig-waste-turned-into…
- www.dukechronicle.com/article/project-creates-energy-source-hog-waste
- http://articles.latimes.com/2011/dec/25/nation/la-na-hogs-waste-20111225
- https://randlereport.com/pig-waste-proves-powerful/
- www.yadkinripple.com/view/full_story/20942720/article-Yadkinacec
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
White Meat-Green Farm: Case Study of Brinson Farms
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Abstract
Comprehensive on-farm resource utilization and renewable energy generation at the farm scale are not new concepts. However, truly encompassing implementation of these ideals is lacking. Brinson Farms operates 10 commercial broiler houses. The farm generates heat for its houses using biomass boilers and litter anaerobic digestion to produce methane. Solar panels assist in heating process water for the boilers and digester. Biomass feedstock includes litter as well as municipal yard wastes. Liquid fertilizer is a product of the digester while residual solids are included in the farm’s composting operation. The operator has used a futuristic approach to not only attain energy independence for the farm, but also to comprehensively utilize byproducts of production and other local “wastes”, diverting them from local landfills. Considering the propane cost for a single winter flock has reached $66,000 and the annual electric bill may be $120,000, energy costs very much affect grower profitability. This approach decreases the uncertainty in energy costs. Brinson Farms provides a unique look into ensuring long-term farm sustainability in an environmentally friendly way and with a wide-ranging systems approach to management.
Purpose
The purpose of the renewable energy project was to implement an innovative, sustainable solution to manage poultry manure and other organic waste products using anaerobic digestion as well as to demonstrate the ability to effectively and economically reduce dependence on outside utilities.
What Did We Do?
Brinson Farms demonstrates comprehensive utilization of local resources that have historically been viewed as wastes. These organic materials (broiler litter, yard trimmings, storm damaged trees and waste vegetables) come from both the farm and the community. Broiler litter and waste vegetables are anaerobically digested to produce methane. The methane is then used in three ways: 1) to generate electricity for the farm; 2) in boilers to heat water used in the digestion process; and 3) in dual-fuel biomass boilers to heat water for heat exchange in the broiler houses when biomass sources are low. Two other significant products from the digester include liquid fertilizer (approximately 5-2-3) that is sold and residual solids that are incorporated into the farm’s composting facility. Solar panels assist in heating water for the biomass boilers and the digester. The simple payback period for the on-farm poultry litter digester system is approximately 5 years.
Brinson Farms anaerobic digester complex. |
What Have We Learned?
Brinson Farms provides a unique system to ensure long-term farm sustainability in an environmentally beneficial manner. Attributes of the integrated system include: 1) bio-based energy production; 2) reduced utility costs; 3) comprehensive litter utilization; 4) no need to land apply poultry litter; 5) production of high quality, organic liquid fertilizer; 6) production of a marketable soil amendment (compost); and 7) diverting wastes from landfills. The farm/community interface is mutually advantageous. The farm uses yard trimmings and trees for energy and as a compost substrate; the community has a free repository to dispose of the biomass, where otherwise it would have to pay landfill fees.
Biomass storage and boiler to heat broiler houses |
Future Plans
Future plans include developing economic evaluations for each of the system components so that farmers can choose the renewable energy/value added process(es) that will best fit their local resources as well as short and long term financial plans.
Authors
Dana M. Miles, Chemical Engineer, USDA-ARS Genetics & Precision Agriculture Research Unit, Mississippi State, MS, dana.miles@ars.usda.gov
Additional Information
John Logan: johnlogan1@windstream.net;
Jeff Breeden: jbreeden@egesystems.com;
Eagle Green Energy: http://eaglegreenenergyinc.com/;
Arora, S. 2011. Poultry Manure: The New Frontier for Anaerobic Digestion. http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1046769.pdf
Acknowledgements
The assistance of John Logan and Jeff Breeden to effectively describe the Brinson system is greatly appreciated.
The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.