Nutrient Recovery Membrane Technology: Pilot-Scale Evaluation

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Purpose

Animal manure contains nutrients and organic matter that are valuable to crop production.  Applying manure to nearby fields can be a significant source of environmental contamination, however, if managed incorrectly. In many cases, concentrated animal production facilities are not close enough to sufficient cropland to fully utilize these resources and management of manure becomes more of a disposal issue rather than a utilization opportunity. One potential solution is to remove and concentrate manure nutrients so they can be cost effectively transported longer distances to cropland that is lacking in nutrients.  The objective of this work was to design and test a pilot-scale system to implement a hydrophobic, gas-permeable, ePTFE (a synthetic fluoropolymer) membrane (U.S. patent held by USDA) to recover ammonia from swine wastewater in a solution of sulfuric acid. The pilot-scale system was designed to replicate the laboratory results and to determine critical operational controls that will assist in design of farm-scale systems.

What did we do?

Through a series of preliminary experiments, we established operational criteria and selected a membrane with an inside diameter of 0.16 in., wall thickness of 0.023 in., and a density of 0.016 lb in-3. A test system was developed (Figure 1) with 19 membrane tubes within a 2.01-inch diameter, 24.7-inch-long reactor, giving a membrane density of 3.83 sq. in. per cubic inch of reactor volume. Wastewater first passed through a CO2 stripping column (4.016 in. diameter, 55 in. length) where a small air stream (0.0614 cfm) stripped CO2 from the wastewater and raised the pH one full unit, shifting the equilibrium to NH3 and enhancing transport across the membrane. Batch tests (0.706 ft3) were run for 9-12 days with wastewater recirculating at a rate of 0.16 gpm. The recovery fluid inside the tubular membranes was a 0.01 N sulfuric acid solution with the pH automatically maintained below 4.0 standard units and recirculating at a rate of 1/100th the wastewater flow rate. Freshly collected settled wastewater and anaerobic digester effluent were tested to determine the mass of ammonia collected, the acid required to maintain the low pH of the recovery solution, and potential ammonia losses to the atmosphere.

Figure 1. Schematic of membrane system

What have we learned?

The freshly collected wastewater had an initial mass of 35.6 g nitrogen but the NH3 was only 14.5 g, leading to a recovery of 11.8 g (33% of initial content) over 12 days. The anaerobic digester effluent had an initial mass of 33.2 g nitrogen with an NH3 mass of 31.3 g. The higher fraction of ammonia helped push the recovery to 25.7 g or 77% of the initial nitrogen content (see Figure 2). Very little ammonia was lost with the exhaust air.

Figure 2. Nitrogen recovery from swine manure with ePTFE membrane

Future Plans

An optimized membrane reactor could be a viable tool in ammonia nitrogen recovery from a manure treatment system if used in conjunction with digestion. Higher economic value could be generated by further concentrating the ammonium sulfate product.

Corresponding author, title, and affiliation

John J. Classen, Associate Professor, Biological & Agricultural Engineering, NCSU

Corresponding author email

john_classen@ncsu.edu

Other authors

J. Mark Rice, Extension Specialist, NCSU; Alison Deviney, Graduate Research Assistant, NCSU

Additional information

John J. Classen

Biological and Agricultural Engineering

Campus Box 7625

North Carolina State University

919-515-6755

Acknowledgements

This project was supported by NRCS CIG Award 69-3A75-12-183. The authors are grateful for the analytical work of the BAE Environmental Analysis Laboratory, Dr. Cong Tu, manager.

Partnerships in the Manure Nutrient Management Field

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Purpose

Responsible manure nutrient management improves environmental quality while maintaining agricultural productivity. Multiple organizations and individuals play a part in improving the understanding and practice of responsible management. But how does manure nutrient management information flow? The “Pathways” project’s goals were to understand and delineate pathways for effective information dissemination and use among various agricultural professional audiences that facilitate successful integrated (research/outreach/education) projects and programs. This presentation examines the relevance of partnerships within the manure nutrient management network and barriers to these partnerships.

What did we do?

We disseminated the “Pathways” survey online utilizing the mailing lists of several professional and producer organizations and listservs associated with manure management. There were 964 surveys started and 608 completed. The six types of organizations with more than 10% of the total survey population’s responses were university/Extension; government non-regulatory agencies; government regulatory agencies; producers; special government agencies; and sale or private enterprises.

The South Dakota State University Institutional Review Board deemed the survey exempt under federal regulation 45 CFR 46.101 (b) (IRB-1402010-EXM and IRB-1502001-EXM).

What have we learned?

The survey posed “How important is collaboration with each of the following groups related to manure nutrient management?” Figure 1 shows the mean relevance among all survey participants, evaluated on a scale of 1 (Not important/somewhat unimportant) to 4 (Highly important). On average, all potential partner groups were recognized as important (>2). Partnerships with producers were deemed most important (3.68) by all survey respondents.

After assessing relevance, we asked survey participants to indicate what barriers, if any, deter them from collaboration with each of the following groups related to manure nutrient management (select all that apply). For all potential partners listed, with the exception of tribal governments, “No Barriers to Use” was the most selected option. “Do Not Have a Relationship” was a common and stronger barrier for commodity, sales and service partners, compared to government agencies, for example.

The barriers “Discouraged or Not Allowed” and “No Incentive to Collaborate” were relatively small selections. The barrier “Do Not Have a Relationship” is possible to overcome at both individual and organizational levels, where needed.

Figure 1. The average relevance and the distribution of barriers to collaborating or partnering with the types of organizations specified, for purposes of manure nutrient management

Future Plans

In the future, assessing the reasons for specific partnerships can further aid improving communication and collaboration in the manure nutrient management network.

Corresponding author, title, and affiliation

Erin Cortus, Associate Professor and Environmental Quality Specialist at South Dakota State University

Corresponding author email

erin.cortus@sdstate.edu

Additional information

lpelc.org/the-pathways-project

Acknowledgements

The Pathways Project greatly appreciates the support of the North Central Region Water Network Seed Grant, South Dakota Sustainable Agriculture Research and Education, and the collaborative groups of educators, researchers and agency personnel, for improving and advocating the survey.

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Recommendations of the Chesapeake Bay Program Expert Panel on Manure Treatment Technologies

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Purpose

The US EPA Chesapeake Bay Program assesses nutrient loading to the Chesapeake Bay. There is a need to determine the impact of manure treatment technologies on reducing the nitrogen and phosphorus loading from agriculture. Furthermore, many states within the Chesapeake Bay Watershed control nutrient discharges through watershed nutrient trading programs. Tables of standard nutrient removal efficiencies of various technologies will allow states to implement these programs.

What did we do?

The panel standing on the dock of the Chesapeake Bay

An expert panel was convened by the EPA Chesapeake Bay Program to determine nutrient removal potential of manure treatment technologies. The following seven technology categories were reviewed: thermochemical processing, anaerobic digestion, composting, settling, mechanical solid-liquid separation, and wet chemical treatment. Within these categories, the panel defined 24 named technologies for detailed review. The scientific literature was reviewed to determine the ability of each technology to transfer volatile nitrogen to the atmosphere and transfer nutrients to a waste stream more likely to be used off-farm (or transported out of the Chesapeake Bay Watershed).

What have we learned?

Manure treatment technologies are used reduce to odors, solids, and organic matter from the manure stream, with only minor reductions in nutrient loading. The panel determined that Thermo-Chemical Processing and Composting have the potential to volatilize nitrogen, and all of the technologies have the ability to transfer nutrients into a more useful waste stream. The greatest effect of treatment technologies is the transformation of nutrients to more stable forms – such as precipitation of insoluble phosphorus from dissolved phosphorus.

Future Plans

The panel’s report is undergoing final authorization from the Chesapeake Bay Program for release to the public. Future panels may choose to revisit the issue of nutrient reduction from manure treatment technologies. The current panel recommends future panels expand the categories of technologies to include liquid aerobic treatment, and examine more named technologies as they become available within the Chesapeake Bay Watershed.

Corresponding author, title, and affiliation

Douglas W. Hamilton, Associate Professor Oklahoma State University

Corresponding author email

dhamilt@okstate.edu

Other authors

Keri Cantrell, KBC Consulting;John Chastain, Clemson University; Andrea Ludwig, University of Tennessee; Robert Meinen, Penn State University; Jactone Ogejo, Virginia Tech; Jeff Porter, USDA Natural Resource Conservation Service, Eastern Technology Suppor

Additional information

https://www.chesapeakebay.net/

http://osuwastemanage.bae.okstate.edu/

Two related presentations given at the same session at Waste to Worth 2017

Acknowledgements

Funding for this panel was provided by the US EPA Chesapeake Bay Program and Virginia Tech University through EPA Grant No. CB96326201

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Inclusion of the Environment Bottom Line in Waste to Worth: The Interaction Between Economics, Environmental effects, and Farm Productivity in Assessment of Manure Management Technology and Policy

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Purpose

In a global context, the pork industry constitutes a huge economic sector but many producers operate on very thin margins. In addition, pork is one of the largest and most important agricultural industries in North Carolina and the United States but faces a number of challenges in regards to waste management and environmental impacts.On more local scales, swine producers face a number of additional constraints including land availability, waste management options (technical and regulatory), nutrient management costs, profits, risk, and return on investment. In the face of increasingly stringent environmental regulations, decreasing land availability, and higher costs for fertilizer, it is necessary to consider alternative technologies with the potential for improving environmental conditions and creating value added products. Technology assessments generally focus on technical performance as the measure of “utility” or usefulness. Primary physical performance measures such as efficiency, production rate, and capacity, while necessary may not be sufficient for capturing the overall value of a technology. A significant amount of research has evaluated the feasibility of technology adoption based on traditional economic measures but far less research has attempted to “value” environmental performance either at farm-scale or in the larger context (e.g. supply chain response to changes in technology or policy and regulation). Considering response over time, the extent to which environmental and economic policies and regulations positively or negatively affect technology innovation, emission and nutrient management, competitiveness, and productivity, remains largely unknown.

The purpose of this study is to evaluate the environmental and economic tradeoffs between current swine waste management practices in North Carolina and alternative scenarios for future on-farm decision making that include new technologies for waste removal, treatment, and nitrogen recovery. In addition, we begin to understand these economic and environmental tradeoffs in the context of various environmental policy and regulation scenarios for markets of carbon, electricity, and mineral fertilizer.

What did we do?

Using waste samples from swine finishing farms in southeastern NC, laboratory and bench scale experiments were conducted to determine the quantity and quality of biogas generation from anaerobic digestion and nitrogen recovery from an ammonia air stripping column. Based on these data as well as information from literature, six trial life cycle assessment scenarios were created to simulate alternatives for annual manure waste management for one finishing barn (3080 head) on the farm. Materials, energy, and emissions were included as available for all system components and processes including but not limited to waste removal from barns (flushing or scraping), treatment (open air lagoon or covered lagoon digester), nitrogen recovery (ammonia air stripping column), and land application (irrigation). A description of the scenarios as well as processes that are included/excluded for each can be found in Table 1. All scenarios were modeled over a one year operational period using a “gate to gate” approach where the mass and energy balance begins and ends on the farm (i.e. production of feed is not included and manure is fully utilized on the farm). It was assumed that each scenario included an existing anaerobic treatment lagoon with manure flushing system (baseline, representative of NC swine farms). In the remaining scenarios, the farm had an option of covering the lagoon and using it as a digester to produce biogas (offsetting natural gas); covering the digester and ammonia air stripping column for nitrogen recovery (offsetting mineral ammonium sulfate); installing a mechanical scraper system in the barn (replaces flushing); and/or different combinations of these. Open LCA, an open source life cycle and sustainability assessment software, was used for inventory analysis and the Tool for Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI 2.0) was used to characterize environmental impacts to air, water, and land. From Table 2 preliminary results indicate that all scenarios had a similar pattern in terms of impact for the assessed categories. The open air lagoon had the highest overall environmental impact followed by scraping manure with digestion and recovery and scraped slurry digestion with no nutrient recovery. Flushed manure to the digester with nutrient recovery had the lowest overall environmental impact, followed closely by scraped whole slurry to the digester with nutrient recovery.

Table 1. Life cycle assessment scenarios with waste management processes included in evaluation

Table 2. Relative impact of scenarios for selected environmental indicators

Using energy and emissions data from the initial life cycle assessment on alternative scenarios for swine waste management systems we have started to characterize the environmental and economic outcomes arising from selected on farm technologies. More specifically we began to examine the regulatory, institutional, and market barriers associated with technology adoption within the swine industry. We provide a theoretical model to support quantification of the change in revenues and expenses that result from changes in three major markets connected to swine production – carbon, electricity, and fertilizer. We examine some of the economic characteristics of environmental benefits associated with changes to farm practices. Finally, we discuss implications for innovation in technology and policy.

What have we learned?

Preliminary results are somewhat mixed and further research is needed to see how sensitive the life cycle assessment inputs and outputs are to system components. While there is a clear indication that covering lagoons, with or without additional nutrient recovery, reduces environmental impact – farm scale systems can be quite expensive and no further determination can be made until a full economic analysis has been conducted. Modeling secondary effects, such as increased ammonia emissions in barns from flush water recirculated from digesters, remains to be included. Besides farm level cost and returns, review of literature has pointed to additional barriers to adoption of reduced environmental impact technologies. Examples of barriers include deficient or non-existent markets for environmental benefits, and various state and federal regulations and policies related to renewable energy, carbon offsets, new farm waste management technology, etc. Solutions such as better cooperation between energy firms, regulatory agencies, and farmers as well as increased financial incentives such as carbon credits, renewable energy credits, net metering options, and enabling delivery of biogas to natural gas pipelines can greatly increase the profitability and implementation of this technology on NC hog farms.

Future Plans

As this is an ongoing multi-disciplinary project, future plans include the expansion of existing data to form a more comprehensive life cycle inventory with options for both new and existing swine farms, which include additional options for waste treatment, nutrient recovery, and land application/fertilizer methods, etc. Energy and emissions data from the life cycle model will continue to be utilized as inputs into a more fully integrated model capable of reflecting the true “cost” and “values” associated with waste management treatment systems. In addition, it is expected that the integrated model will include the flexibility to simulate overall costs and returns for various sizes of operations within the county, region, and if possible state-wide.

Corresponding author, title, and affiliation

Shannon Banner, Graduate Student, North Carolina State University

Corresponding author email

sbcreaso@ncsu.edu

Other authors

Dr. John Classen, Dr. Prince Dugba, Mr. Mark Rice, Dr. Kelly Zering

Acknowledgements

Funding for this project was provided by a grant from Smithfield Swine Production Group

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

PA Finishing Swine Barn Experience: Changing from Mortality Burial to a Michigan Style Composting Barn

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Purpose

In the spring of 2014, the farmer with a 2020 finishing pig barn, wanted to change from burial of mortality to composting the mortality. We will document the change and the use of the composting barn from July 2014 to Dec 2016.

What did we do?

This 2020 finish pig barn space has about 3% mortality and expects about 250 deaths per year to compost. We discussed building a PA Michigan single wall compost barn design. The farmer built a 24×40 compost barn, with a 3 feet center dividing wall. The barn was completed in the summer of 2014 and we will track the pig barn turns and compost barn mortality loadings from July 2014 to December 2016. The barn has used about 56 cubic yards of woodchips/ bark mulch the first year and then replaced with about 40 cubic yards of sawdust for the second year.

The compost temperatures have reached 130 Degrees F and the farmer is very pleased with how the barn works and how he can mix and turn the compost. The presentation will cover barn costs, barn design and sawdust mortality loading and turning.

Field with windmills and barn
PA Michigan compost barn built at the end of the hog barn

Compost heap under shelter
Excellent example of free flowing air into the compost piles while
having a center push up wall to help turn the piles

What have we learned?

We have documented the farmers use of the barn, the mortality rates, compost sawdust and woodchip use, and mixing schedules. We have also documented the mortality cost rates for this farm.

Future Plans

We will highlight this PA Michigan compost barn type to other pig barns and document the use of them in Pennsylvania.

Corresponding author, title, and affiliation

J Craig Williams

Corresponding author email

Jcw17@psu.edu

Additional information

http://extension.psu.edu/animals/health/composting

http://msue.anr.msu.edu/program/info/managing_animal_mortalities

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Organizing demonstrations and tours for Government officials and Extension on Animal Mortality Management

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Purpose

Provide some discussion on putting together Tour and Demonstration educational events. To Provide real life demonstrations and educational opportunities dealing with Mortality management.

What did we do?

The agent participated on a multi-state and multi country steering committee to organize and host an international symposium on Animal Mortality and Disposal Management. This was the 5th symposium and had 179 registered attendees from 11 different countries: Australia, Canada, China, Georgia, Korea, New Zealand, Nigeria, the UK, the US, Tunisia, and Vietnam.

The agent served as the host state coordinator (Penn), the 3 bus tour coordinator and the demonstration’s chairperson. Demonstrations included high density foaming, compost pile building and turning, environmental grinder processors, Clean Harbor Industries,  truck wash stations, and proper euthanasia with cap and bolt guns. The agent will list the success and challenges of these types of demonstrations and educational events. Results are from the 5th International Symposium on Managing Animal Mortality, Products, and By-products, and Associated Health Risk: Connecting Research, Regulations and Response at the Southeast Agricultural Research and Extension Center on Wednesday, September 30, 2015.

Moving horse for mortality composting
Examples of demonstrations during the field day

What have we learned?

Excellent industry tours and Farm tours and Demonstrations are an excellent learning opportunity. All Parties including Extension, Farmers, Industry and government personnel can benefit from hands on education.  Those in attendance gained skills and knowledge to be able to host their own training sessions and to be better prepared to handle animal mortality outbreaks and events in their own state.  They gained a first hand experience on pile building and related technologies for this type of event.

Demo with tractor covering mortality composting pile
Turning of a 60 day compost pile

Future Plans

The International Committee on Animal Mortality and Waste Products is a collection of University researchers and educators, State Department of Agriculture, Federal Homeland Security and Environmental Protection Agency personnel. The committee plans to meet for future International Symposiums as needed.

http://animalmortmgmt.org/symposium/contributors/

Corresponding author, title, and affiliation

J Craig Williams, County Agent, Penn State Extension

Corresponding author email

jcw17@psu.edu

Additional information

Conference website

http://animalmortmgmt.org/

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Spotlight on Manure Management in North Carolina and the Atlantic Coastal Plains


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Purpose 

To provide information about commonly-found manure management systems and approaches in North Carolina and the Coastal Plains, and discuss opportunities for technological innovation in the areas of manure management and nutrient recovery/utilization. Hear from a diverse panel of researchers, animal agriculture producers, and agency representatives who will provide background on the environmental conditions of the region and discuss specific technical considerations for innovative research and development. Learn about what has and hasn’t worked in past attempts to recover nutrients at animal agriculture farms in the area, and about the exciting possibilities for innovation in the U.S. Environmental Protection Agency’s (EPA’s) Nutrient Recycling Challenge (www.nutrientrecyclingchallenge.org).

What did we do? 

N/A

What have we learned? 

N/A

Future Plans 

N/A

Corresponding author, title, and affiliation 

Joseph Ziobro, Physical Scientist, U.S. Environmental Protection Agency; Hema Subramanian, Environmental Protection Specialist, U.S. Environmental Protection Agency

Corresponding author email 

ziobro.joseph@epa.gov; subramanian.hema@epa.gov

Other authors

Dr. John Classen, Associate Professor and Director of Graduate Programs, College of Biological and Agricultural Engineering at North Carolina State University

Dr. Kelly Zering, Professor of Agricultural and Resource Economics, North Carolina State University

Additional information

Session Agenda

  1. Background, history, and technical information about manure management in North Carolina and the Coastal Plains

Presenter: Dr. John Classen, Associate Professor and Director of Graduate Programs, College of Biological and Agricultural Engineering at North Carolina State University

  1. Lessons Learned from the Smithfield Agreement

Presenter: Dr. Kelly Zering, Professor of Agricultural and Resource Economics, North Carolina State University

  1. Panel: Challenges and Opportunities around Manure Management Systems

Moderator: Hema Subramanian

Panel to include the above speakers plus representatives from the local animal agriculture industry, North Carolina Department of Agriculture and Consumer Services, North Carolina Department of Environmental Quality, and U.S. Environmental Protection Agency. 

Digester Effluent’s Agronomic and Odor Emission Potential: A Swine Case Study


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Purpose

This on-farm study looked at the full-scale treatment effects of anaerobic digestion on the composition of manure effluent from an agronomic and air quality perspective.  The goal was to improve our understanding of the role that anaerobic digestion may play in managing manure as a fertilizer and in reducing odor and other air emissions.

What did we do?

Manure slurry and digester effluent samples were collected from a swine production operation in eastern Nebraska that utilizes a complete-mix anaerobic digester to treat the manure and produce biogas for generating electricity.  Samples were collected from three sites in the manure stream (below-barn pit, digester outlet, and holding pond) over a 15-month period to observe changes in manure and head-space gas composition as a result of manure treatment and over time.  Manure analyses included common agronomic measures (N-P-K, pH, micronutrients, etc.) and measures of biological decomposition potential (i.e. chemical oxygen demand, volatile solids content).  Gases released by manure samples (‘head-space air’) were analyzed for odor precursors (i.e. volatile fatty acids, aromatic compounds, and ammonia).

Swine production  operation in eastern Nebraska where manure slurry and digester effluent samples were collected.

The manure nutrient analyses were then used to determine nitrogen-based application rates for a later comparison of fertilizing dryland corn using i) undigested manure from deep pits; ii) digester effluent; iii) digested manure held in earthen storage; and iv) anhydrous ammonia (control).  Material for each treatment was knifed into duplicated test strips using commercial injection equipment.  Each strip was 30 feet wide (twelve 30″ rows) x 360 feet long for an area of 1/4 acre.  The yield for each strip was obtained at harvest using data from the combine’s yield monitoring system.

What have we learned?

A trend was observed for ammonia nitrogen (NH3-N) content of the digester effluent to be greater than in the raw manure [influent], but then NH3-N dropped substantially during subsequent storage in the earthen basin.  These observations are consistent with anticipated ammonia generation during digestion (as organic nitrogen is converted to aqueous ammonia ) followed by loss of ammonia to the atmosphere as the treated manure is stored in an open structure.  When considering effects on fertilizer value, the study provided supporting evidence that a digester has very little direct effect on total nitrogen content, but tends to increase NH3-N content.  Similar corn yields (averaging 156 to 163 Bu/Ac) were obtained for each treatment.   Our conclusion was that digesters increase the availability of nitrogen in manure for plant growth, which unfortunately may also increase losses of this valuable plant nutrient via ammonia volatilization.

Volatile solids (or total organic matter) and chemical oxygen demand (COD) contents in stored digester effluent showed considerable decreases from undigested manure in the below-barn pit.  Loss of volatile solids and COD as the manure moved through the digester and during storage in the basin is consistent with consumption of organic matter and production of methane and other biogases.  Another clear trend was for odorous compounds to decrease in concentration as the manure slurry moved through the digester and as the effluent was subsequently stored in the basin.  When the digester was operating as designed, chemical oxygen demand was reduced by an average of 45%, odorous volatile fatty acids were reduced by an average of 66%, and ammonia increased by an average of 58%.

Future Plans

None at this time

Corresponding author email

rstowell2@unl.edu

Other authors

Dan Miller, USDA-ARS and Crystal Powers, UNL

Additional information

Related research report (National Pork Board #08-259) at http://research.pork.org/Results/ResearchDetail.aspx?id=1578.

Acknowledgements

Funding for this work was provided by the National Pork Board (#08-259) and the Nebraska Environmental Trust. Appreciation acknowledged for in-kind efforts of the pork producer and owner of O’Lean Energy, LLC.

Closing Abandoned Livestock Lagoons Effectively to Utilize Nutrients and Avoid Environmental Problems

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Purpose

In Nebraska alone, nearly 400 earthen manure storage structures are in operation; approximately four dozen requests to cease operation of permitted lagoons were received by the Nebraska Department of Environmental Quality in the prior decade with many more non-permitted storage structures being in need of proper closure. Abandoned livestock lagoons, earthen manure storage basins, and other manure storages (e.g. concrete pits) need to be decommissioned in a manner that controls potential environmental risk and makes economical use of accumulated nutrients. Currently, limited guidance is available to support lagoon closure planning and implementation and few professionals who support livestock producers have experience planning or participating in the manure storage closure process. The main focus of this project was to produce two videos that document the processes for planning and executing a lagoon closure.

What did we do?

The University of Nebraska Haskell Ag Laboratory, located near Concord, NE, had an anaerobic lagoon that was operated for over 20 years, but has not received swine manure additions since 2009 when the swine unit was depopulated. The decommissioning of this storage structure was proposed in 2014 and provided our team an opportunity to plan, implement and document the procedures necessary to properly close this structure. When we went to find material on how to accomplish this properly, we did not find suitable material. Two grants were secured in 2016 from the U.S. Pork Center of Excellence (USPCE) to fund our team efforts to document the closure process – from planning to completion – with two separate videos. The first video is focused on the planning activities necessary to prepare for removal and utilization of stored liquid and sludge. The second is focused on the liquid and sludge removal and utilization activities, decommissioning of conveyance structures, and deconstruction of the lagoon berm to return the site to a natural grade.

Activities conducted to execute the lagoon closure have included:

1) Mapping of sludge levels with sonar and analyzing sludge samples to estimate volume and nutrient content of sludge, which enabled development of a land application plan for utilizing the products

Figure 1. Sonar sludge mapping

Figure 1. Sonar sludge mapping.

2) De-watering the lagoon (effluent used for sprinkler irrigation and flood irrigation)

3) Hosting a demonstration event during which participants:

a. observed sludge removal and land application processes,

b. participated in a manure spreader calibration,

c. inspected the soil beneath the lagoon liner,

d. viewed the abandoned production buildings and heard about options for eliminating conveyance of liquid from the building to the lagoon,

e. explored alternative sludge removal methods, and

f. participated in a classroom session where presenters shared details of the closure planning process, cost-share opportunities for closure of manure storage structures, and expectations for re-grading and re-seeding the site following removal of sludge.

Figure 2. Participants learned about planning land application of the sludge

Figure 2. Participants learned about planning land application of the sludge.

Figure 3. Land application of the sludge and calibration of the manure spreader

Figure 3. Land application of the sludge and calibration of the manure spreader.

4) Removing the sludge and applying it to cropland following the demonstration event.

Documentation of all planning, demonstration, and closure execution activities have been captured via extensive video footage, still photos, and participant interviews. Production of the videos is in process with completion and release of videos anticipated in summer 2017.

What have we learned?

Although every manure storage closure process is expected to present its own unique challenges and opportunities for learning, the process documented during this project has provided a number of insights:

1) While this process involved pumping liquid from the lagoon prior to attempting sludge removal in order to observe the sludge layer and document the volume present, a more appropriate, and likely more effective, process is to agitate the storage prior to and during pumping activities to enable handling all of the material as a slurry;

2) Dewatered sludge volume (nearly 200,000 gallons) and nutrient content (44.2 lbs. TKN, 37.5 lbs. organic N, 89.3 lbs. P2O5 and 7.6 lbs. K2O per 1,000 gallons) for this system yielded enough nutrients to apply to 80-100 acres, based on a phosphorus removal rate. It is unknown what the release of the organic N component of the sludge will be, but using just the phosphorus content, application of 1000 gallons per acre would provide enough phosphorus for what would be removed from 220 bushels of corn, which is worth approximately $35 with winter 2017 prices.;

3) Given the high phosphorus content in the sludge and that the nearby fields at the Haskell Ag Lab were not in need of phosphorus, an appropriate application rate for the sludge was determined as 8-10 tons/acre;

4) Soil beneath the lagoon liner yielded a phosphorus concentration of 556 ppm, likely a result of an inadequate liner in the lagoon as originally constructed in the 1960s; and

5) Installation of a bentonite clay liner during renovation of the structure in 1992 appeared to be effective as the liner was fully intact when observed during closure activities.

Pre-post surveys completed by 33 attendees of the demonstration event revealed that attendees improved their confidence in performing six key tasks identified by the team as being impactful. Results are summarized in Figure 4.

Figure 4. Impacts of the lagoon closure demonstration event

Figure 4. Impacts of the lagoon closure demonstration event.

Future Plans

We plan to continue the decommissioning process by:

1) Completing sludge removal and application to cropland;

2) Deconstructing the berms, leaving the liner intact, and returning the area to natural grade;

3) Seeding the area to establish ground cover and mitigate runoff and erosion; and

4) Plugging the inlet pipes in manure pits within the animal housing in lieu of removing buried conveyance pipes.

The two videos are in production and will be made available through the Pork Information Gateway (www.porkgateway.org) during summer 2017.

Corresponding author, title, and affiliation

Leslie Johnson, Research Technologist, University of Nebraska – Lincoln

Corresponding author email

ljohnson13@unl.edu

Other authors

Charles Shapiro and Amy Schmidt, University of Nebraska – Lincoln

Additional information

https://water.unl.edu/article/animal-manure-management/lagoon-closure-and-your-environmental-responsibility

Acknowledgements

The authors would like to recognize the U.S. Pork Center of Excellence (USPCE) for funding the development of the videos documenting this process and enabling us to complete this project. We would also like to acknowledge that without the support of the industry, who provided equipment and advice, we would not have been able to get this project off the ground. Also a special thanks to the Agricultural Research Division for their support.

Recovery of Ammonia and Production of High-Grade Phosphates from Digester Effluents


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Purpose

Conservation and recovery of nitrogen and phosphorus from animal wastes and municipal effluents are important because of economic and environmental reasons. This paper presents a novel technology for separation and recovery of ammonia and phosphorus from liquid swine manure, which has significant amount of nutrients but also contains relatively high moisture content.

What Did We Do?

Phosphorus recovery via magnesium (MgCl2) precipitation was enhanced by combining it with ammonia recovery through gas-permeable membranes and low-rate aeration. Detailed procedures used in the research are provided in Vanotti et al. (2017).

Graphic of gas-permeable membrane

What Have We Learned?

The combination of low-rate aeration and gas-permeable membrane N recovery destroyed the natural carbonate alkalinity in the wastewater and increased pH values, which accelerated ammonia uptake in the gas-permeable membrane system and improved the phosphate recovery.  The process provided 100% phosphorus recovery efficiencies.   Surprisingly, the magnesium phosphates produced contained very-high phosphate grade (46% P2O5 ) similar to commercial superphosphate fertilizer and consistent with the composition of a rare biomineral called newberyite  that is found in guano deposits.   This is an important finding because we were able to produce from wastes a valuable phosphate product with high P2O5 content favored by the fertilizer industry.

Future Plans

Research will be summarized showing consistent results obtained with municipal side-stream effluents.  Economic considerations are provided in Dube et at. (2016).

Corresponding author (name, title, affiliation) 

Matias Vanotti, USDA-ARS

Corresponding author email address  

matias.vanotti@ars.usda.gov

Other Authors 

M.B. Vanotti, P.J. Dube, A.A. Szogi, M.C. Garcia-Gonzalez

Additional Information

Dube, P. J., Vanotti, M. B., Szogi, A. A., and García-González, M. C. (2016): Enhancing recovery of ammonia from swine manure anaerobic digester effluent using gas-permeable membrane technology. Waste Management 49:372–377.

Vanotti, M.B., Szogi, A.A., and Dube, P.J.  (2016): Systems and methods for recovering ammonium and phosphorus from liquid effluents. U.S. Patent Application 15/170,129. U.S. Patent and Trademark Office.

Vanotti, M.B., Dube, P.J., Szogi, A.A., M.C. Garcia-Gonzalez (2017): Recovery of ammonia and phosphate minerals from swine wastewater using gas-permeable membranes. Water Research 112:137-146

Acknowledgements

This article is part of USDA-ARS Project 6082-12630-001-00D “Improvement of Soil Management Practices and Manure Treatment/Handling Systems of the Southern Coastal Plains.”  We acknowledge the field and laboratory assistance of William Brigman and Chris Brown, USDA-ARS, Florence, SC, and the field sampling assistance of Diana Rashash, North Carolina Extension Service/ North Carolina State University.

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.