Process for Recovery of Phosphorus from Solid Manure

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Why Study Phosphorus Recovery?

Land application of manure in regions with intense confined livestock and poultry production is an environmental concern when land is limiting because it promotes soil phosphorus (P) surplus and potential pollution of water resources. A net accumulation of soil P results from the disproportion between lower nitrogen (N) and P ratio (N:P) in animal manure and the higher N:P ratio in harvested crops. Although manure can be moved off the farm, its transportation becomes less economical with increasing distances from the source. Thus, management alternatives to land application are needed to resolve agronomic P imbalances for more effective recycling of manure P.

Litter washed solids residue – Low P content

What Did We Do?

A treatment process, called “quick wash”, was developed for extraction and recovery of P from poultry litter and animal manure solids. In the quick wash process, P is selectively extracted from solid manure or poultry litter by using mineral or organic acid solutions. Following, P is recovered by addition of liquid lime and an organic poly-electrolyte to the liquid extract to form a calcium-containing P precipitate. The quick wash process generates two products: 1) washed solid residue, and 2) concentrated recovered P material.

What Have We Learned?

Recovered concentrated P material

The quick wash process selectively removes up to 80 % of the phosphorus from manure solids while leaving most of the nitrogen in the washed litter residue. Consequently, the washed solid residue has a more balanced N:P ratio for crop production and environmentally safe for land application. The concentrated  P recovered materials contained more than 90% of its phosphorus in plant available form. The use of recovered P can provide a recycled P source for use as crop fertilizer while minimizing manure P losses into the environment from confined animal production.

Future Plans

USDA granted an exclusive license of the invention to Renewable Nutrients, LLC (Pinehurst, NC); a centralized plant for treating poultry litter is planned to be built and operated by Renewable Nutrients in the Mid-Atlantic region.

Authors

Ariel A. Szogi, Research Soil Scientist, USDA-ARS Coastal Plains Soil, Water, and Plant Research Center,  Florence, SC. ariel.szogi@ars.usda.gov

Ariel A. Szogi, Matias B. Vanotti, Patrick G. Hunt – USDA-ARS Coastal Plains Soil, Water, and Plant Rsearch Center,  Florence, SC.

Additional Information

https://www.ars.usda.gov/is/pr/2008/080229.htm

https://www.frontiersin.org/articles/10.3389/fsufs.2018.00037/full

Szogi, A.A., Vanotti, M.B., Hunt, P.G., 2008. Process for removing and recovering phosphorus from animal waste. U.S. Patent and Trademark Office Application Serial No. 12/026,346.

Szogi, A.A., Vanotti, M.B., and Hunt, P.G. 2008. Phosphorus recovery from poultry litter. Trans. ASABE 51(5):1727-1734.

Szogi, A.A. and Vanotti, M.B., 2009. Prospects for phosphorus recovery from poultry litter. Bioresour. Technol. 100(22):5461-5465.

Szogi, A.A., Bauer, P.J., and Vanotti, M.B. Fertilizer effectiveness of phosphorus recovered from broiler litter. Agron. J. 102(2):723-727. 2010.

Acknowledgements

This work is part of USDA-ARS National Program 214: Agricultural and Industrial Byproducts; ARS Project 6657-13630-005-00D “Innovative Bioresource Management Technologies for Enhanced Environmental Quality and Value Optimization.”

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Case Study: Poultry Lagoon Closure in Texas

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Abstract

The closure of earthen lagoons associated with a caged egg-laying operation was used as a case study.  This case study presents information on the steps taken to close the lagoons, including topographic survey needs, analysis of sludge and wastewater at different times during the closure process, methods for excavating and removing the sludge, and the costs associated with the closure of earthen lagoons.  The sludge has a high fertilizer value for P2O5 and other micro- and macro-nutrients.  The cost of the closure for this case exceeded the expected cost for the earthwork for the construction of a new facility

Why Present a Case Study on Propoer Lagoon Closure?

Provide the steps taken to close the lagoons, including topographic survey needs, analysis of sludge and wastewater at different times during the closure process, methods for excavating and removing the sludge, and the costs associated with the closure of earthen lagoons.  These steps will hopefully assist others in the future closure of lagoons.

What Did We Do?

Performed closure of earthen lagoons for a caged egg-laying operation that existed for over 35 years in Gonzales County, Texas.  The 100 ft by 400 ft football field sized lagoon area with 5 – 12 ft deep sludge had accumulated approximately 20,000 cubic yards of sludge.  The photo below depicts the three lagoon areas (Infrared photograph of site depicting two lagoons and smaller wastewater storage area (USDA-NAPP, 1983).

Multiple different options for closure of the lagoon were evaluated.  Sampling in-situ materials to determine if the existing system had a realistic potential for seepage.  Detailed analysis of the sludge and wastewater were performed throughout the project.  A detailed survey of the site determined the existing volumes of sludge and wastewater.  Civil 3D and Eagle Point software programs assisted in development of a final grading plan for the site.

Construction drawings and specifications were developed to place the site into pre-existing conditions. The construction project was split into four phases:  Phase 1 – Sludge and Wastewater Removal; Phase 2 – Removal of Sludge to Nearby Agricultural Operation; Phase 3 – Demolition of Concrete Slabs and Final Grading; and Phase 4 – Establishing Vegetation on Site

Site plan generated for construction plans depicting the natural grade compared to the constructed grade of the poultry houses. (USDA-NRCS, Poultry Lagoon Closure Construction Drawings, March 2008)

Irrigation pump for the removal of wastewater (TSSWCB, 22 June 2009)

Use of field conveyor belts to stack sludge on-site.  (TSSWCB, 28 June 2009)

What Have We Learned?

Formal contracting potentially increases the cost of the project; however, observance of worker safety laws is more likely .  Initially this project was sent for bid as a turn key project consisting of 18,500 CY of sludge to be removed and land applied, removal of concrete slabs, placement of 27,000 CY of compacted earthfill, final grading and establishment of vegetative cover.  As part of the bid, the contractor was to secure a location for the sludge to be land applied or find another use for the sludge.  The bids received ranged from $1.8M up to $3M.  This level of funding was not available, so the project was split into different phases.  By breaking into phases, the cost of the project was reduced by over 75%.  Costs for application or hauling of sludge can be reduced by having an agreement in place prior to contracting.

The cost of the project was close to $250,000 for construction and sludge hauling without consideration of other costs, such as engineering design work, sample analysis, and staff time.  The earthwork associated with the construction of this site for a new facility with the excavation and placement of 27,200 CY of compacted earthfill would have been completed for approximately $70,000.

With flexible scheduling, it was possible to find a landowner that was willing to pay for the hauling and land application of sludge, which reduced the out-of-pocket expenses for the closure by more than $90,000.

The amount of Phosphorus present in the sludge was compared to the cost of commercial fertilizer.  As of February 2011, Rock Phosphate with 32% P2O5 was selling at $160/metric ton (Index Mundi, 11 June 2012), therefore P2O5  was $500 per metric ton.  Using the hauled weight of 12,100 tons with a moisture content of 25.9% and 5.66% P and a conversion factor of 2.29 for P to P2O5, there was 1,160 tons (1,054 metric tons) of P2O5.  At the rate of $500 /metric ton, the P2O5 in the sludge would have a value of $525,000.  There is additional fertilizer value for the other constituents that are not included.

Future Plans

This case study provides much needed data for the closure of similar operations across the United States.  The data collected will be used for future closures under the NRCS Environmental Quality Incentives Program (EQIP).  The construction specifications that were developed for this project can be adapted into general specifications for future closure projects.  Additional work is needed to compare the value of the sludge to a fertilizer value.  The potential for a portable pelletizing and bagging system for recycling sludge from lagoons warrants further research.

Authors

Catherine Nash, Water Resources Engineer, USDA – Natural Resources Conservation Service Catherine.nash@tx.usda.gov

Additional Information

“Case Study:  Closure of Earthen Lagoon”, An ASABE Meeting Presentation, Paper No. 1336921

Archived webinar  – Poultry Lagoon Closure – Case in Progress

Acknowledgements

Contributions from Texas Poultry Federation, Gonzales Soil and Water Conservation District, Texas State Soil and Water Conservation Board (TSSWCB), USDA – Natural Resources Conservation Service (NRCS), Texas Water Resources Institute, Farm Pilot Project Corporation, Inc. (FPPC) and others made this project possible. A special thanks to:  John Foster, TSSWCB, and James Grimm, Texas Poultry Federation, for initiating the project and keeping it moving forward;  Lee Munz, TSSWCB for assistance with surveying and taking the lead on his first construction project; John Mueller, NRCS for his support and guidance through the process; Ace Fairchild, NRCS, for his enthusiasm and support throughout the project; Wayne Gabriel, NRCS, for assistance with soils identification; Tom Beach, NRCS, for evaluating feasibility of other options for closure; Shawn Higgins for assistance, endurance and encouragement with the development of Engineering Drawings and Specifications.  Thanks to Gonzales County Soil and Water District Employees who helped throughout the project, including:  Jeremiah Ford, Abigail Lindsey, Shari Johnson, Jessi Goodson and Wain Fairchild.  Thanks to TSSWCB staff including: Lawrence Brown, Jeff Cerny, Amy Devereaux, TJ Helton, Dawna Winkler, and Kenny Zajicek.  Thanks to USDA-NRCS staff including:  James Davis, Andria Heiges, Jeff Porter, Doug Sharer, James Smith, and Millie Stevens.  Thanks to AgriLife Extension members:  Saqib Mukhtar, Biological and Agricultural Engineering Department; and Sam Feagley, Department of Soil and Crop Sciences.  Every person that was asked for assistance responded graciously and enthusiastically in a timely manner.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.