manure treatment – Page 9 – Livestock and Poultry Environmental Learning Community

March 5, 2019March 6, 2019

A Novel Treatment System to Remove Phosphorus from Liquid Wastes

Lowering the total phosphorus (P) content of animal manures is one means of addressing concerns over P runoff following land application of animal manure. We developed a treatment system for liquid manures that conserves the manure nitrogen (N) content while removing most of the manure P content. Initial evaluation of a treatment system involving manure solid separation and precipitation of dissolved P with an alkaline salt (calcium hydroxide) resulted in poor liquid/solid separation and poor dissolved P removal and created conditions promoting ammonia-N volatilization. As a result, we developed a three step system with iterative solid removal and acid salt (ferric sulfate) precipitation of dissolved P: (1) removal of bulk and intermediate sized solids (>25 Î¼m); (2) chemical treatment to convert dissolved P; and (3) final removal of fine solids and chemically precipitated P. When tested on manure slurries from 150 and 2700 cow dairies, 96 and 99% total P was removed respectively, resulting in liquid manure filtrates with up to 400:1 N:P ratio. While costs of treatment were roughly $38 per kg P removed, equivalent to $750 per cow annually, we anticipate that refinement of the process and beneficial uses of the solid materials (bedding, compost, etc.) will improve cost-efficacy considerably.

Author

Church, Clinton Clinton.Church@ars.usda.gov USDA-ARS

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.

March 5, 2019July 15, 2020

Case Study of Contaminated Compost: Collaborations Between Vermont Extension and the Agency of Agriculture to Mitigate Damage Due to Persistent Herbicide Residues

Why Study Herbicide Contamination of Compost?

Picloram, clopyralid, aminopyralid and aminocyclopyrochlor are broadleaf herbicides commonly used in pastures due to effectiveness in controlling undesirable plants and the very low toxicity for animals and fish. In fact, some of these herbicides do not require animal removal post application. The grazing animals can ingest treated leaves with no ill health effects, but may pass the herbicides through to the manure. Also see: Composting Livestock or Poultry Manure

When a complaint driven problem of damaged tomatoes and other garden crops in Vermont was traced back to a single compost provider in Chittenden County in Vermont, a series of actions and reactions commenced. Complaints were fielded and investigated by personnel from the Vermont Agency of Agriculture, Food and Markets (VT-AG) and the University of Vermont Extension (UVM-EXT). The compost provider sent samples of various components of the compost to a single laboratory and received positive results for persistent herbicides in sources of equine bedding/manure components. Subsequent interviews by the facility manager in both print and television media seemed to cast blame on Vermont equine operations for ruining Vermont gardens. Coincidentally, the composter had recently changed compost-processing methods. Initial samples sent to a separate laboratory did not support the composter’s laboratory results. Samples of feed, manure, shavings, and many other components which were shipped to several laboratories by VT-AG, resulted in extremely inconsistent and/or contradictory data between laboratories running the exact same samples.

What did we do?

Several processes were underway by several agencies in a coordinated and collaborative effort to resolve and mitigate the herbicide issues:

• Vermont Agency of Agriculture, Food and Markets was receiving and investigating complaints.

• University of Vermont Extension plant biology personnel were identifying, documenting, and sampling affected plants, as well as counseling gardeners.

• University of Vermont equine extension worked with horse owners and media to mitigate unsubstantiated claims of “horses poisoning garden plants”.

• A more thorough investigation by VT-AG involved collection of raw samples (feed, hay, shavings, manure) from 15 horse farms who utilized the compost facility to dispose of manure and bedding.

• The VT Secretary of Agriculture and the VT-AG Agri-chemical Management Section Chief were brought together with equine and compost experts attending the NE-1041 Equine Environmental Extension Research group annual meeting hosted by UVM equine extension.

• VT-AG worked with herbicide manufacturers to use high quality testing equipment and procedures to gather consistent data from samples.

What have we learned?

More extensive details of this particular case have been published in the Journal of NACAA (http://www.nacaa.com/journal/index.php?jid=201).

• The levels of persistent herbicides were low enough that they were below the acceptable limits for water, yet they still harmed sensitive garden plants.

• Nationally and locally manufactured grains tested positive for persistent herbicides; most likely due to the individual components being treated within legal limits during field production.

• Many of the laboratories were unable to provide accurate or consistent results when testing for the persistent herbicides.

• Discussions between the NE-1041 group and VT-AG resulted in a fruitful exchange of information, as well as development and delivery of pertinent information for the general public and County Agricultural Agents.

Future Plans

Several proactive activities have already been initiated and/or completed. A peer reviewed case study on all aspects of the contaminated compost has been published in the Journal of NACAA; and two episodes of Vermont’s Agricultural television show (Across the Fence) were created to educate and update the general public on the situation. A Vermont compost working group has been assembled and set goals to create potential educational materials including a horse owner pamphlet (in final editing phase), a farmer/livestock pamphlet, and press releases for the public education on challenges with persistent herbicides. The VT-AG website has a Compost FAQs page addressing the most common questions associated with compost and herbicides.

Authors

Betsy Greene, Professor/Extension Equine Specialist, University of Vermont Betsy.Greene@uvm.edu

Carey Giguere, Agrichemical Management,Vermont Agency of Agriculture

Rebecca. Bott, Extension, South Dakota State University

Krishona. Martinson, Extension, University of Minnesota

Ann Swinker, Extension, Penn State University

Additional information

• Greene, E.A., R.C. Bott, C. Giguere, K.L. Martinson, and A.W. Swinker. 2013. “Vermont Horses vs. Twisted Tomatoes: A Compost Case Study. J of NACAA. 6:1 (http://www.nacaa.com/journal/index.php?jid=201)

• Vermont Agency of Agriculture, Food and Markets Compost FAQ’s: http://agriculture.vermont.gov/node/696

• Davis, J. Dept. of Horticultural Science, NC State University. 2010. Herbicides in Manure: How Does It Get there and why Should I Care?, Proceedings 8th Annual Mid-Atlantic Nutrition Conference, Timonium, MD. pp 155-160.

• Across the Fence Television Show: An Update on Green Mountain Compost Contamination and Testing-Greene/ Gigliuere (9/14/12)

• Across the Fence Television Show: Information from NE 1041 Meetings and National Equine Specialists-Greene (9/17/12)

• Article from Minnesota Extension explaining the problem in hay and how to avoid it. The article is devoted to “ditch hay”, but the information is relevant to all hay. https://extension.umn.edu/horse-nutrition/managing-herbicides-ditch-forages

• Washington State University Web site on clopyralid carryover includes pictures of affected vegetables, research results, and the bioassay protocol http://www.puyallup.wsu.edu/soilmgmt/Clopyralid.htm

• Dow Agrosciences United Kingdom website with information on aminopyralid: http://www.manurematters.co.uk/

• CDMS Agro-chemical database with access to all the herbicide labels: http://www.cdms.net/LabelsMsds/LMDefault.aspx?t

Acknowledgements

The State University Extension Equine Specialists that make up the NE-1441: Environmental Impacts of Equine Operations, Multi-State Program. USDA.

March 5, 2019May 7, 2019

Composting and the Benefits: Achieving Practice Change through Education to Reduce Nutrient Loads and Increase Adoption of Best Management Practices

Purpose

Florida houses roughly 500,000 horses and is also home to 700 freshwater springs; Marion County is, “Horse Capital of the World” and houses two first magnitude springs and each is currently in a restoration plan with the Florida Department Environmental Protection Agency (FDEP). The Florida Department of Agriculture and Consumer Services (FDACS) equine Best Management Practices (BMP) Manual recommends composting as an excellent manure management option.

Composting is a controlled biological process that decomposes and heats up organic material to produce a biologically stable humus, which can then be used as a rich soil amendment. Composting provides protection to the ground and surface waters by preventing excess nutrients from being leached out and running-off into the waters. It destroys up to 90% of weed seeds contained in manure and kills parasite eggs and pathogens. Additionally, the organic matter/compost helps prevent and control soil erosion and can improve both soil quality and productivity.

What did we do?

Individual and group programming has been developed to educate farm owners and managers about the benefits derived from composting horse manure/spent bedding. Since 2007, Over 800 farms have been seen in the county. In 2013 alone, 132 participants were involved in individual farm consultations or farm revisits, group presentations and composting workshops. Education was provided and supplemental materials were developed for clientele about composting manure, compost bin construction and composting’s soil-improvement capabilities. Compost Countryside

What have we learned?

Pre and post-test results showed a 62% (82 of 132 total participants) knowledge gain from information taught. A total of 71% (n=12 of 17 farm revisit consultations) of farms revisited improved and adopted recommended manure handling practices after receiving education. Additionally, seven farms and facilities have begun cost-share planning with Southwest Florida Water Management District (SWFWMD) for compost bin construction. Results/impacts show improved management practices and a greater understanding of BMPs, allowing for a decrease in nutrient levels to the ground and surface waters. Pictures show sample bins which were constructed as a result of individual and group programming.

Future Plans

Continued group and individual programming needs to be continued, in partnership with trade journal articles being written about manure management, protection of the ground and surface waters and the benefits derived from composting manure/bedding. Cost-share dollars, coming from state organizations, will further incentivize farms to construct and use compost facilities as part of a regular manure management plan.

Author

Jamie Cohen, Farm Outreach Coordinator, UF/IFAS Extension Marion County jamiecohen@ufl.edu

Additional information

My eXtension.org Manure Management Strategies Webcast: https://connect.msu.edu/p8yko9zhhoq/?launcher=false&fcsContent=true&pbMode=normal

eXtension.org –Manure Management page: https://lpelc.org/horse-manure-management/

A Guide to Composting Horse Manure: www.whatcom.wsu.edu/ag/compost/horsecompost.htm

March 5, 2019July 15, 2020

Economical Anaerobic Digestion of CAFO Animal Waste

Purpose

The application of manure on croplands is increasingly under regulatory scrutiny, especially from impaired watersheds. The challenge facing many small farms is to find cost-effective and innovative solutions for manure reuse whilst responding to environmental, regulatory and public concerns. One option is to install an anaerobic digester (AD) in which microorganisms break down biodegradable material in the absence of oxygen. However, not all farmers are financially able to install an AD but do need the AD’s benefits to keep their livestock operation sustainable. This paper discusses a novel, cost effective and patented manure treatment system which can reduce the volume of manure for field application (see Figure 1). Earthmentor N2RTS Schematic

What did we do?

The EarthMentor® Natural Nutrient Reclamation and Treatment System (EMS), uses a combination of innovative sand separation technology (if necessary) and anaerobic treatment to concentrate manure nutrients into solid phases and treat approximately 70% of manure liquids into a product which can be applied to active cropland as low-nutrient liquid using irrigation methods. The primary economic advantage of using an EMS to treat livestock manure prior to land application is lower total manure disposal costs. The total manure handling costs are reduced because up to 75 % of the original manure volume can be handled as low-nutrient value irrigation quality liquid in bulk instead of hauling it by tanker for land application. This fact alone reduces total manure handling costs by over 50 %. Other tangible benefits of using an EMS include low odor, minimized environmental risks, and greater flexibility in proper land application of the treated manure. It can be installed at farms with as few as 250 cows. Depending on farm size, operators can realize a return on investment in as little as three years. Compared to a traditional AD installed to generate biogas the EMS is simple to operate, requires less energy, requires no chemicals or substrates to treat the waste, and reduces manure disposal costs.

The EMS involves six major steps: 1) collection of raw manure and transport to the processing center, 2) sand bedding is separated from the manure stream, 3) coarse manure components are removed from the liquid manure stream, 4) additional settling of the fine manure solids and sand particles occurs in a settling basin to a concentration of 8 to 10 percent solids, 5) AD treatment of the liquid manure and dissolved solids occurs in anaerobic treatment lagoon (ATL), and 6) The ATL effluent is stored in a Storage Pond for eventual discharge to active growing crops; additional natural treatment of the liquid manure occurs while in the Storage Pond.

All settling basins and ATL lagoon must meet state guidelines, such as Natural Resource Conservation Service technical guidelines or state requirements for waste storage facilities.

The ALT of the EMS system has a smaller footprint compared to traditional ALTs (primarily use in the south and western United States) because the majority of the nutrient-rich semi-solids are removed from the manure before discharge to the ATL. Due to this major operational change the EMS is economical to install and operate even in the northern climates of the United States where many of the top producing dairy states are located. While many facilities separate solids before land application, the EMS is different because is adds the AD step which converts the manure into a low-nutrient liquid capable of irrigation-style land disposal. The method of solid separation can be as simple as a sloped screen followed by additional gravity separation as described in Step 4 above. The EMS ATL must be sized to account for reduced biodegradation during the colder weather. The EMS has successfully operated at multiple swine facilities and several Midwestern dairy farms.

If there is sufficient land near the farmstead, the EMS can be installed at existing dairies with minimum difficulty since the treatment system works equally well with multiple bedding materials and varying manure collection methods. Another benefit of the EMS is that is allows application on fields that may be high in phosphorus since much of the phosphorus will be stored in the accumulating ATL sludge. For dairies bedding with sand, a patented sand removal system can be provided that relies on a decanting method of sand separation. Once the sand is removed, it can be reused in the barn.

What have we learned?

Typical Cost Savings for Manure Application Using EMS
Component	Disposal Method	Conventional Manure Handling		EarthMentor^® Treatment System Handling
Liquid Manure	Land Application	100%	$0.02/gallon	0%	$0
Separated Solids	Land Application	0%	$0	10%	$0.016/gallon ($4/ton equiv.)
Heavy Slurry	Land Application	0%	$0	20%	$0.02/gallon
Treated Wastewater	Center Pivot over Crop	0%	$0	70%	$0.002/gallon
Combined Cost		100%	$0.02/gallon	100%	$0.007/gallon (weighted average of all components)

Using financial data from 2010 for a 2,000-cow Michigan dairy, it was estimated that the cost to handle manure using an EMS is reduced from $0.02/gallon to $0.007/gallon. The cost saving using the EMS is based on the assumption that the average dairy cow produces nearly 25 gallons/day of manure, including wastewater but excludes bedding since farms used different types and volumes of bedding for their dry and lactating cows. Based on the financial analysis, installation of an EMS benefits the farm’s economic sustainability while providing other benefits including reduced environment risk associated with manure land application.

Far beyond the obvious cost savings associated with the EMS installation, a livestock producer will realize many other benefits. A partial list is provided below:

This practical and manageable manure treatment system requires little or no additional farm labor commitments yet greatly reduces overhead expenditures to keep the farm sustainable and competitive,
All manure is treated prior to land application (environmentally sound),
The more consistent high solids slurry can be precisely applied to fields with the greatest need as opposed to the highly variable manure nutrient concentrations recovered from a traditional manure pond,
Minimizes the environmental risks (ecologically viable) and farm nuisance potential,
The window of opportunity for manure application is extended to over 200 days instead of being limited to spring and fall applications for typical liquid manure,
Can provide a safe unlimited recycled bedding source for cattle, if so desired, by the dairy owner,
Permits farmer to follow BMPs for soil conservation,
Permits farmer to follow timing, rate, source, and place for fertilizer/crop nutrient applications,
Benefits the non-farm neighbors and community through reduced nuisance odors, and
Continues using the farm’s manure as a soil amendment for crop production, the most efficient use known.

Future Plans

The immediate future plans for EMS is to target small livestock producers, especially those within impaired watersheds. Since many ADs need a substrate material imported from outside the farm to be economically sustainable, the EMS is ideal for those farms that want to be good neighbors with reduced farm air emissions, need greater convenience in manure management, and desire to maximize the real cash value of their manure.

As the EMS adapts well to any bedding material, by investing time and dedicating property for the ATL any size operation can begin to treat their manure prior to land application and reduce their overall cost for manure management.

In addition to small farms we envision four possible adaptations of EMS; these examples are provided to show the transferability of this technology to farms desiring various outcomes from an EMS:

Installation of an Energy-Generating AD – if a farm wishes to generate energy using a traditional AD, it would be installed prior to the EMS system whereby the AD digestate discharges into the settling ponds. Since the residence time of a traditional AD is measured in days, there is a great deal of additional treatment that can occur so that the cost savings for land application can still be realized.
Use manure solids for other uses besides land application – if the livestock producer decides to bed their cattle on manure solids or to compost the manure solids for sale off-farm to landscapers or bag and sell direction from the farm then the solids from the SS can be further treated with a screw press or roller then composting by various means.
Greenhouse gas capture and sale of carbon credits – a geosynthetic liner cover can be added to the ATL and all captured gases burned through a flare. However, it should be noted that by removing a significant amount of high organic solids during the initial fiber solids separation step, much less organic material is subject to organic degradation into methane gas.
Greenhouse gas capture and burning of the gases – to generate electricity or heat water (typically for on-farm use or export to an adjoining business, such as a greenhouse).

One future issue to resolve includes educating state governments on the benefits of installing an EMS, especially for those farms that may be under a Consent Order or other regulatory actions or those farms that may need to implement a manure treatment system to mitigate odors from the livestock operation. The duration to install an EMS and get it operational is much shorter than the lead time to design and install a traditional AD so the EMS can help when farms need to implement changes quickly. A second issue to overcome is to properly educate producers on the benefits of EMS and differences between traditional ADs. Swine, beef, and dairy producers who already have a farm irrigation system will have a lower capital investment to begin achieving the reduced manure management costs referenced above.

Author

Matthew J. Germane, P.E., President at Germane Environmental Consulting, LLC MGermane@GECEnvironmental.net

Additional information

https://www.gecenvironmental.com, Envirolytic Technologies, LLC

Acknowledgements

Acknowledgements to Envirolytic Technologies, LLC, Greenville, OH manufacturer of the Earthmentor® N2RTS system and RAM Technologies, LLC, manufacturer of the sand separation equipment used in the EMS for their assistance in providing the laboratory data used in this paper.

March 5, 2019July 6, 2020

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.

March 5, 2019July 15, 2020

Making Dairy Manure More Valuable Than Milk

Can Anaerobic Digestion Lead to Additional Revenue Streams On a Dairy Farm?

CowPots are the invention of necessity. Brothers Matt and Ben Freund are second generation dairy farmers in the northwest hills of Connecticut. In dairy farming, the most challenging job is to manage the nutrient stream in an environmentally sound manner. In 1997 the brothers installed a methane digester to heat the manure coming out of a cold barn to be able to separate the liquid year round for field application with a drag line system. This made the farm much more efficient and timely while at the same time reducing soil compaction and improving crop yields. The solids which are composted were first used for bedding the herd and are now used to mold the CowPots, whose value far exceeded bedding value. Farmers and gardeners have always considered cow manure a wholesome organic soil amendment for their crops. The challenge was to find a new and better way to get manure to these soils while maintaining value to consumers.

CowPots are a patented, environmentally friendly product made from the nutrient rich manure and are a vehicle for exporting the farm’s excess nutrients. Through production and sales of CowPots the Freunds have reduced the nutrient load on their farm by approximately 11% and have added a significant 2nd income to the dairy operation.

Examples of CowPots Root Example

Emblems of sound stewardship, CowPots are the ideal product for farmers, growers, gardeners — and for the planet.

What did we do?

The idea for using manure solids to fashion a horticultural pot occurred in the mid 1990’s. The dairy farmer’s wife, Theresa owns a seasonal farm market and garden center adjacent to the dairy farm. Matt noticed that when his wife was tilling the soil each spring, the supposed biodegradable pots were still fully intact.

Confronting stricter regulations on nutrient management through state and federal rules, he needed an alternative to the status quo of storing and spreading manure on their 260+ cow dairy farm. Comparing the fibers found in the peat pots to the fibers of the manure solids, he brought his idea to the kitchen. In Matt’s spare time he began forming, pressing, pasting and molding manure fibers into pots (initially working in the greenhouse and using equipment from his wife’s kitchen and not wanting to get divorced, he moved outside to the farm shop). Nearly a decade was spent experimenting through trial and error.

In the mid 2000’s a production prototype was constructed in one bay of the farm shop where 4” pots were formed and placed by hand onto a drying oven. In 2006, CowPots worked with a local company to shrink wrap stacks of pots and sold them for resale at local garden centers and hardware stores in the tri-state area. That same year Freunds received an SBIR grant to further investigate the horticultural benefits of growing in CowPots. Concurrently, UConn and Cornell University conducted trials in greenhouse settings. In 2009, a standalone manufacturing facility was built and the lineup of sizes offered grew. Today the Freunds manufacture 12 size pots for horticultural uses as well as custom shapes for customers.

What have we learned?

Freunds have learned not all dairy fibers are the same. There are numerous activities on any farm which affect the characteristics of this material. Changes in feed, added minerals, digester upsets,composting temperatures, duration in the in-vessel composer and pasturing the herd have been the most influential on Freund’s farm.

Matt Freund with Product CowPots

Future Plans

The Freunds had many goals one of which was not to have CowPots dictate the management of the dairy. Every bucket of manure fiber needs to be tested before it is used for production of CowPots. The equipment is adjusted in response to any changes.

Another goal was to design a production facility with no waste stream. Dry matter of the fiber is very important to achieve this goal. By having nothing but water vapor and finished product exiting the facility, permitting becomes much less difficult and our footprint becomes much smaller.

The CowPots manufacturing facility is fast approaching their production capacity with shifts that run 24/6. New automation in the packaging system will be installed in the coming months for a total of three robots in the facility. Currently, Freunds are putting together an expansion plan to include an additional production line. They are also working with a company in a similar business to look for synergies. Freunds are investigating other waste streams which could be blended with CowPots products to make the end product even better and at a reduced cost. Recently an engineer came on board to identify production inefficiencies within the manufacturing system to help reduce costs. As the market builds, Freunds will be looking for partners to work with in different areas of the country.

Author

Matt Freund, Owner/Inventor matt@cowpots.com

Additional information

http://cowpots.com/

https://www.youtube.com/user/CowPots

Acknowledgements

Northeast SARE, SBIR, USDA NRCS and Rural Development, CT Dept of Agriculture and CT Dept of Energy and Environmental Protection

March 5, 2019March 6, 2019

Renewable Natural Gas – Biogas Cleaning and Upgrading 101

With depressed electrical prices for produced biogas, many projects are now moving towards business models predicated on production of renewable natural gas (RNG). In order to produce RNG, projects must first clean and upgrade raw biogas to pipeline and/or transportation fuel quality through the use of various engineering approaches. In this presentation, an overview of available and emerging biogas cleaning and upgrading technologies are discussed, highlighting positives, negatives and costs.

Who Should Consider Biogas Cleaning?

The aim of this fact sheet is to provide farmers, third party project developers, regulatory agencies, and other stakeholders with a basic understanding of the chemical composition of renewable natural gas, the most appropriate end use options for dairy digesters, and some of the more common techniques used to clean biogas to RNG quality at dairy digesters.

What did we do?

The authors utilized years of research and industry expertise as well as thorough literature search describe the concept of renewable natural gas and the technologies to clean the biogas. The authors aimed to provide information based on the current literature, but not to favor one technology over another.

What have we learned?

When CHP is the end-use of biogas, the most common biogas purification approach for dairy digesters in the US is to remove water vapor and hydrogen sulfide. Existing projects use a variety of approaches, ranging from biological processes (both post digestion and via oxygen injection into the digester) to physical-chemical absorption processes such as iron type-sponge or activated carbon.

However, if RNG is the end-use a higher degree of purity is required. Often times a dedicated water vapor removal unit and hydrogen sulfide scrubbing unit is still required for removal of the bulk of the hydrogen sulfide mass. Thereafter, water scrubbing or PSA are often used to remove carbon dioxide from biogas, producing an RNG fuel that can be utilized in a variety of different ways. Other technologies exist, however their application on dairy digesters has been rather limited due to concerns related to maturity, cost, and complexity. The best technique is also situation-specific, and therefore, it is critical to understand the mechanics of each purification process, its limitations, and its economics before making a decision.

As electrical rates continue to drop throughout the PNW and US, current and new AD project developers are strongly considering a shift from CHP towards higher value end-uses for biogas, particularly RNG. Interest is increasing due to a growing CNG industry in the US, the decoupling of CNG and diesel prices, and the potential for competitive pricing and high revenues in comparison to fossil-CNG, given existing government incentives. Projects are presently limited and business models must still be proven before wide-scale adoption of biogas upgrading technologies within a dairy digester platform. In addition, concerns historically plaguing CHP projects, related to power purchase agreement pricing, interconnection fees, and scaling are still potentially present within a pipeline fuel model. Nonetheless, the potential exists for a new business model approach to AD projects on US farms.

Future Plans

No future plans.

Authors

Craig Frear, Assistant Professor, Washington State University cfrear@wsu.edu

Nick Kennedy, Associate in Research WSU; Georgine Yorgey, Associate in Research WSU; Dan Evans, President Promus Energy; Jim Jensen, Associate in Research, WSU Energy; Chad Kruger, DIrector WSU CSANR

Additional information

For those seeking additional detail, or information about other technologies, more comprehensive reports and reviews are available (Jensen, 2011; Krich et al., 2005; Ryckebosch et al., 2011). This publication is part of the Anaerobic Digestion Systems Series, which aims to provide information that improves decision-making for anaerobic digestion systems.

Acknowledgements

This research was supported by funding from USDA National Institute of Food and Agriculture, Contract #2012-6800219814; National Resources Conservation Service, Conservation Innovation Grants #69-3A75-10-152; Biomass Research Funds from the WSU Agricultural Research Center; and the Washington State Department of Ecology, Waste 2 Resources Program.

March 5, 2019March 6, 2019

Manure Technology Video Series

Can Video Be Used as a ‘Virtual’ Tour?

Producers are reluctant to adopt new technologies without firsthand experience with the technology. It is particularly difficult to get positive exposure for manure related issues in traditional media. Creative methods are needed to expose producers to useful technologies for handling and treating animal wastes. The OSU Waste Management Youtube channel was created to provide virtual tours of manure treatment and handling technologies.

What did we do?

Fourteen videos highlighting innovative manure handling and treatment technologies were filmed, edited, and produced by the Oklahoma Cooperative Extension Service. We specifically sought out producers who successfully adopted technologies to the particular conditions of their farms.

What have we learned?

In its five years of existence, the OSU Waste Management Youtube channel has been viewed more than 53,000 times (120,000 minutes viewed) from 183 countries and all fifty states – plus Guam, Puerto Rico and the District of Columbia.

Future Plans

We will continue to add new videos to the channel.

Authors

Douglas W. Hamilton, Associate Professor Oklahoma State University dhamilt@okstate.edu

Craig A. Woods, Video Producer/Director Ag Communication Services, Oklahoma State University

Additional information

https://www.youtube.com/user/OSUWasteManagement

March 5, 2019March 6, 2019

Technologies for Anaerobic Digestion of Flushed Swine Manure

Hog farmers face a unique challenge to implement digestion — namely the low volumetric methane yield of wet swine manure. The most common digester used on hog farms using flushing systems is the covered lagoon. This presentation explores the technical feasibility of high rate reactors for low solids swine manure. Systems compared are Contact Stabilization Reactors, Upflow Anaerobic Sludge Blanket Reactors (UASB), Fixed Filmed Reactors, and Anaerobic Sequencing Batch Reactors (ASBR). Contact Stabilization and UASB technology have been available since the 1970s, but are mostly found in industrial settings. Their main drawback for swine manure treatment is the required operator skill level. UASB digesters also have difficulty handling the uneven solids flow from flushed or pull-plug barns. Fixed film reactors have been successfully used in agriculture, but require solids separation before digestion. The separator creates two waste streams and removes organic matter that could potentially be available for digestion. ASBR technology was developed in the 1990s. An ASBR digester was successfully operated at the Oklahoma Swine Research and Education Center in the 2000s. Hydraulic retention time for this farm scale ASBR ranged between 5 and 20 days. Maximum methane yield was 0.55 m3 CH4 kg-1 VS day-1. Organic matter reduction efficiency was 50 to 75 % measured as Chemical Oxygen Demand (COD). Current work on solids settling and retention will allow ASBR digesters to reach their full potential in swine production systems. Related: Treatment Technologies for Livestock Manure

Why Consider Anaerobic Digestion on Pig Farms?

Anaerobic digestion can reduce the carbon footprint of swine production, while substantially lowering the fossil fuel energy required to feed and raise hogs. However, economic analyses show that anaerobic digestion on swine farms using complete mix digesters to produce electrical energy have a net negative present value unless carbon credits in the price range of $10 to $12 per metric ton of CO2eq are given for methane emissions reduced (Cowley, 2015). The two factors negatively affecting the economic viability of complete mix digesters are high capital cost and relatively low biogas output of reactors. Capital cost of digesters is directly related to the hydraulic retention time (HRT) of reactors. Farm-scale complete-mix digesters treating swine manure have retention times ranging from 18 to 30 days (Fisher, et al., 1979; Schulte, et al., 1985; Zhang, et al., 1990). Methane yields of these digesters was between 0.22 to 0.25 m3 CH4 kg-1 V S, and reactor volumetric efficiencies ranged between 0.35 to 0.40 m3 CH4 m-3 reactor day-1.

What did we do?

High rate digesters are reactors that separate solids retention time (SRT) from HRT. High rate reactors shorten HRT, which results in smaller, less costly digesters. High rate digesters also have higher methane yields than complete mix reactors. Several high rate systems have successfully treated swine manure at the laboratory and pilot scale. Systems tested include fixed film, suspended particle attached growth (SPAG), and upflow anaerobic sludge blanket (UASB) reactors treating the liquid portion of swine manure after solid-liquid separation; and contact stabilization, anaerobic sequencing batch (ASBR), and anaerobic baffled (ABR) reactors treating whole, diluted swine manure. ASBR systems have used both single reactor and multiple reactors in series. Despite the success of laboratory studies, few farm-scale high rate reactors exist on the farm scale.you

What have we learned?

A 400 m3, single vessel ASBR was operated for two years on a 128 sow farrow-to-finish hog farm at the Oklahoma State University Swine Research and Extension Center. (Hamilton and Steele, 2014) . Methane yield was 0.55 m3 CH4 kg-1 VS, and COD removal efficiency was 73% when operated at a 20 day HRT with operating temperature ranging between 22 and 32oC. Methane yield was 0.38 m3 CH4 kg-1 VS and COD removal efficiency was 57% when operated at a 5 day HRT with operating temperature between 22 and 24oC. The digester, as built, was 4 times larger than it needed to be. Using microbial kinetic modeling, the volumetric efficiency of a 100 m3 digester operating at 5 day HRT was estimated to be 0.73 m3 CH4 m3 reactor day-1.

Future Plans

Further work with ASBR digesters is underway. We are working to improve the mixing, settling, and solids trapping efficiency of the ASBR. ASBR reactors are also highly adaptable to receive high energy low solids digestion co-products. Pilot testing has shown volumetric efficiency of swine manure ASBR can be increased 4 to 6 fold with augmentation with waste glycerol from biodiesel production.

Author

Douglas W. Hamilton, Associate Professor at Oklahoma State University

dhamilt@okstate.edu

Additional information

Cowley, C. 2015. Economic Feasibility of Anaerobic Digesters with Swine Operations. Unpublished Thesis. Stillwater, OK: Oklahoma State University.

Fisher, J.R., N.F. Meador, D.M. Sievers, C.D. Fulhage, and E.L. Iannotti. 1979. Design and operation of a farm anaerobic digester for swine manure. Trans ASABE 22(5):1129.

Hamilton, D.W. and M.T. Steele. 2014. Operation and performance of a farm-scale anaerobic sequencing batch reactor treating dilute swine manure. Trans ASABE. 57(5):1473.

Schulte, D.D., Kottwitz, T.J. Siebenmorgen. 1985. Design and operation of a flexible cover, precast concrete anaerobic digester for swine manure. Pp 509-515, in Agricultural Waste Utilization and Management, Proceedings of the 5th International Symposium on Agricultural Wastes. St Joseph, MI: ASABE.

Zhang, R.H., J.R. North, and D.L. Day. 1990. Operation of a field-scale anaerobic digester on a swine farm. Applied Engineering in Agriculture. 6(6):771.

March 5, 2019March 6, 2019

Composting of Dairy Manure and Grape Vine Prunings as a Tool to Better Manage Both Industries Waste and Reduce Their Environmental Impact

Why Look at Grapevine Prunings As a Compost Feedstock?

The objectives of this research and Extension project were:

To determine the impact of mixing grape vine prunings with dairy manure in a compost mix on the composting process and final product.
In particular, we were interested in determining if nitrogen gets fixated into the compost mix with increased carbon content.
To evaluate if composting is a workable alternative to annual grape vine prunings burning. Stopping this annual burning will reduce vineyards environmental footprint.
To demonstrate three different on-farm composting techniques. Mechanically turned (MT), passive aerated (PA), and forced aerated composting (FA).

What did we do?

field day at compost piles We teamed up with a grape and a dairy producer and we built a series of windrows to showcase the three different composting techniques and to research the effects of mixing both waste streams. Grape vine prunings were grounded and mixed with open lot dairy manure. Carbon content of the mix was adjusted to meet organic production standards since the vineyard hosting the project was certified organic. Since the carbon to nitrogen ratio (C:N) of the grounded grape vine prunings was on the low side (80:1), horse stable sawdust and straw from the local county fairgrounds were also used to help increase the C:N. Three replications of each system (MT, PA, and FA) were built with the enhanced carbon mix. A third set of three replications with dairy manure as received (some straw but no added carbon) were built using the mechanically turned system (MTMA) to serve as a control and comparison for that system. In addition to collecting data to evaluate th e effects of the added carbon, the project included two field days where all the systems, how to construct them, and their advantages and challenges were showcased.

What have we learned?

carbon to nitrogen ration The initial feedstock mix C:N was significantly higher in the carbon enhanced windrows as expected, but the final C:N ratio of the compost was not significantly different among most systems and between the enhanced mix and the just manure mix (Figure 1). The C:N reduction between the initial mix and the final compost was significant in all systems of the carbon enhanced windrows, but not significant in the just manure mix (MTMA).

As expected, the initial mix total nitrogen (TN) was significantly lower in the carbon (C) enhanced windrows compared to the just manure windrows (Figure 2). TN in the finished compost had no significant difference among all the systems. The difference between the initial mix and final compost TN wasn’t significant among C enhanced windrows, but highly significant in net values (10.08 Lb/T of N on dry weight basis; p<0.0001) on the just manure windrows. This difference in TN, coupled with the no significant difference in C:N, suggests the loss of nitrogen as ammonia during the composting process in the windrows made of just manure. Net nitrogen loss was significantly lower in the C enhanced windrows (1.45 Lb/Ton).

salts Salts concentrations (mmhos) difference between initial mixes and final compost was significant in all windrows, with higher values in the final compost as expected due to the concentration effect that composting volume reduction has (Figure 3). Salt concentrations in the just manure windrows were significantly higher compared to the carbon enhanced mix. There is a dilution effect when carbon is added in the initial mix (lower manure mass per initial mix unit). Similar dilution trends were observed for phosphorous (P), potassium (K), and micronutrients. Carrying this dilution effect in the final compost can be beneficial when land applying compost since application rates can be increased, increasing the nitrogen and carbon content of the application (desirable conditions) by the time the limiting components in our soils (usually P, K, or salts) are reached.

Screening of the carbon enhanced windrows generated a refuse (bigger size particles) containing pieces of grape prunings that can be used as mulch to control weeds in the vineyard or other production units. When PFRP is achieved, plant pathogens in the mulch can be considered absent or inhibited, and the mulch will be usable on the same or similar plant species.

The PA and MT windrows with enhanced carbon mix reached USEPA-PFRP. FA system didn’t reach PFRP and had an incomplete composting process because of the lack of moisture in the initial mix due to problems with water supply during their construction. Other studies conducted by the authors using FA with similar feedstock had reached PFRP. MTMA windrows didn’t reach PFRP, a common event in the region due to the low carbon content of dairy manure.

Future Plans

This project demonstrated that composting of dairy and potentially other livestock manures mixed with woody wastes from the grape industry or similar agricultural products is not only feasible but beneficial for both industries. Further research is necessary to determine how different carbon and animal manures sources, especially harder woods, will affect the composting process and the final product.

Authors

Mario E. de Haro-Martí. Extension Educator. University of Idaho. mdeharo@uidaho.edu

Mireille Chahine, Extension Dairy Specialist
Tony McCammon, Extension Educator
Ariel Agenbroad, Extension Educator. University of Idaho

Additional information

Unpublished data. Please contact the author, Mario E. de Haro-Martí at mdeharo@uidaho.edu or 208-934-4417.

Acknowledgements

The authors want to thank the participating grape and dairy producers for their collaboration. This project was funded by an Idaho USDA-NRCS Conservation Innovation Grant (CIG).