anaerobic digester – Livestock and Poultry Environmental Learning Community

March 5, 2019July 15, 2020

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.

March 5, 2019March 26, 2019

Anaerobic Digestion of Finishing Cattle Manure

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Purpose

The concept of utilizing feedlot manure in an anaerobic digester to power an ethanol plant, which then produces feed for cattle, has been called a closed loop system. In this system inputs are minimized and outputs are used by another component. This research looked at differences in manure quality within this system. Trial 1 considered incorporating distillers grains into the cattle diet and the effects on methane potential of the manure. For this system to be utilized by the feedlot industry in Nebraska, the manure collected for anaerobic digestion must be collected from soil-based open feedlot pens which account for over 95% of the feedlot cattle raised in Nebraska. Trial 2 addressed the methane potential of open-lot feedlot manure and its feasibility for anaerobic digestion.

An integrated biorefinery utilizes distillers grains for cattle feed and cattle manure for biogas generation to power an ethanol plant. This system has been referred to as a “closed loop” system due to energy recycling within the segments.

What Did We Do?

Seven continuously stirred anaerobic digesters were used to compare degradation of manure from 2 cattle diets (Trial 1) and 2 cattle housing methods (Trial 2). In Trial 1 manure was collected from confinement cattle on a control diet with 82.5% dry rolled corn or 40% of the corn was replaced with wet distillers grains plus solubles (WDGS), a byproduct of the ethanol industry. For Trial 2, manure was collected from cattle in complete confinement or soil-based open feedlot pens with all cattle on a similar byproduct diet. In both trials, organic matter (OM) degradation and methane production was measured for digesters on each treatment. In Trial 1, samples of effluent removed from the digesters were also used to identify differences in microbial community structure (Eubacterial and Archaeal) due to treatment.

What Have We Learned?

Trial 1. Organic matter degradation was slightly improved for manure from cattle fed WDGS (P = 0.10). Methane production was 0.137 L/g OM fed for WDGS manure and 0.116 L/g OM fed for the corn-based diet (P = 0.05). Microbial communities identified using 454-pyrosequencing revealed structuring of the microbial community based on diet (P < 0.001). This suggests that the microbial food chain that contributes to methane production is greatly influenced by the diet fed to cattle, and dietary manipulation may provide opportunities to increase or decrease methane production from cattle manure.

Trial 2. Manure collected from open-lot pens had an OM content of 26% compared to 88% for manure from complete confinement. This resulted in decreased methane production and OM degradation (P < 0.01) for digesters fed open-lot manure. However, methane was produced from open-lot manure suggesting that if ash buildup can be avoided open lot manure may be a viable feedstock for anaerobic digestion.

Future Plans

We are currently exploring new technologies that may enhance the use of open lot manure in anaerobic digestion. We are also identifying key microbes involved in methane production in order to better understand how things such as cattle diet affect methane production.

Authors

Andrea Watson, graduate student, University of Nebraska awatson3@unl.edu

Samodha Fernando, assistant professor, University of Nebraska

Galen Erickson, professor, University of Nebraska

Terry Klopfenstein, professor, University of Nebraska

Additional Information

A summary of these trials is available at beef.unl.edu/reports; 2013 Beef Report pg. 98-99.

Acknowledgements

Funding provided by Nebraska Center for Energy Sciences Research

Anaerobic Digestion of Finishing Cattle Manure from LPE Learning Center

March 5, 2019March 6, 2019

Anaerobic Digester Operator Discussion Group

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Why Is Peer-to-Peer Discussion Important?

The Anaerobic Digester Workforce Development Project is a project funded by the New York State Energy Research and Development Authority, aimed at developing and delivering high quality educational programs targeted to a range of workforces within the dairy farm-based anaerobic digestion (AD) sector of the clean energy field.

A goal of the project was to form a farmer driven discussion group among existing AD owners and operators. Farmers value and learn from the insights of fellow producers because they trust the experience and knowledge of others who are in situations similar to their own. This is especially true when adopting new technology. The purpose of this discussion group was to allow farmers an opportunity to learn from each other by sharing their real world experiences integrating and operating an anaerobic digester system into their farm business. Realizing that frequent, long-distance travel of all involved was a barrier to continued, dedicated involvement, the group opted to pursue a virtually-based discussion group platform. Farmers from across the state were linked via an online meeting site. This is an efficient method to allow farmers to interact with each other in a meaningful way without leaving their farm. The use of high definition video conferencing enhanced the interaction considerably. There have been many lessons learned from this challenging venture, as well as many successful communication strategies to share.

What Did We Do?

Realizing that frequent, long-distance travel of all involved was a barrier to continued, dedicated involvement, the group opted to pursue a virtually-based discussion group platform. Farmers from across the state were linked via an online meeting site. This is an efficient method to allow farmers to interact with each other in a meaningful way without leaving their farm.

What Have We Learned?

The focus of this presentation is to introduce the topic of forming and facilitating farmer based discussion groups with an emphasis on distance learning. By using online meeting and video conferencing farmers from across geographic areas can meet and engage in meaningful dialogue. This is especially useful when producers are implementing new technology in which they have no or limited experience. The opportunity to have an open dialogue with other farmers that have real world experience with the technology is invaluable. The experience and exchange of knowledge between farmers assists in the implementation and operation of the technology.

Future Plans

The virtual discussion group will continue to meet and develop. As we gain more experience and farmers become more comfortable with this method of interact we expect for the discussions to increase in value and effectiveness.