Progress 03/15/18 to 03/14/23
Outputs
Target Audience:The main target audience is the research community in the field of nutrient cycling and management and sustainable phosporus use/reuse. An additional target audience is the agricultural community who employ animal wastewater treatment and nutrient recovery and soil nutrient management. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate students were supported by this project during the last year. How have the results been disseminated to communities of interest?Results have been disseminated through the peer reviewed literature and via conference presentations. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
World reserves of phosphorus, an element essential for food production, are limited, posing concerns for sustainable and affordable food production. In addition, current agricultural practices result in significant loss of phosphorus to the environment from animal wastes. This project investigated sustainable processes for recovering phosphorus from animal wastewaters using materials derived from low-cost agricultural wastes, then reapplying the collected phosphorus as an effective, low-cost fertilizer. The potential benefits are two-fold: recovery and reuse of a limited resource, and reduction of adverse environmental impacts from phosphorus loss to the environment. During this reporting period, we completed Objective 4. Wecompared the environmental impacts and cost of providing phosphorus fertilizer using the commercial fertilizer monoammonium phosphate (MAP) with three novel sorbents that had been exposed to phosphorus rich model animal wastewaters. The novel sorbents were corn cob chars amended with either Mg(OH)2 (Mg-char (Mg(OH)2) or bittern (Mg-char (bittern)), and calcium silicate hydrate (CSH) synthesized from Ca(OH)2 and rice husk ash. Environmental impacts and costs were compared at pH 8.5, 7.0, and 5.5. Both Mg-chars had lower environmental impacts than MAP at all pH values. Corn cob pyrolysis and corn farming, and (for Mg-char (Mg(OH)2) production of Mg(OH)2) contributed the most to the environmental impacts for the Mg chars. The environmental impacts of MAP were dominated by phosphoric acid production. CSH had higher environmental impacts than any other material due to its high biomass and material inputs, arising from its comparatively low solubility and poor release of phosphorus in simulated soil. Mg-char (bittern) had the lowest environmental impacts and cost since it was derived from a natural Mg source (model seawater bittern) rather than a commercial chemical source. CSH had the highest cost of any fertilizer due to its comparatively low solubility--meaning more of it was required to release a given mass of phosphorus--and both Mg-chars had lower costs than MAP for all pH values. The biggest contributor to the cost of Mg-char (Mg(OH)2) was Mg(OH)2 production, so natural mineral or seawater sources of Mg have the potential to lower the cost of fertilizer production. Using Mg-chars for phosphorus recovery and reuse could be beneficial environmentally and economically, thereby helping achieve a more sustainable phosphorus cycle.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Butler, E. C., Ding, Y., Sabatini, D. A. (2022), Phosphate uptake by precipitation in model animal wastewaters: Adjusting ionic strength and ionic composition to maximize phosphorus removal, Water 14, 2229. https://doi.org/10.3390/w14142229.
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Ding, Y., Sabatini, D. A., Butler, E. C. (2023), Effects of pH and Soil Minerals on Phosphorus Release from Agricultural Waste-Based Sorbents: A Continuous-Flow Column Study, Journal of Environmental Engineering 149(4), 04023010. https://doi.org/10.1061/JOEEDU.EEENG-7102.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2023
Citation:
Ding, Y., Sabatini, D. A., Butler, E. C. (in review), Agricultural waste-based sorbents for phosphorus recovery and reuse: A life cycle and cost assessment.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2023
Citation:
Ding, Y. Performance and Environmental Impact Assessment of Agricultural Waste-Based Sorbents for Phosphorus Recovery and Reuse. PhD Dissertation, School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2020
Citation:
Evaluation of Phosphorus Recovery and Release Performance of Calcium Silicate Hydrate Made from Rice Husk. MS Thesis, School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Ding, Y., Sabatini, D. A., Butler, E. C., Phosphorus recovery and reuse by modified agricultural wastes: Release of phosphorus from spent materials under simulated rainfall, Oklahoma Governor's Water Conference and Research Symposium, Midwest City, OK, Dec. 7-8, 2022.
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Progress 03/15/21 to 03/14/22
Outputs
Target Audience:The target audience of the efforts during this reporting period is the research and science community. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate student research assistants have been funded by this project. How have the results been disseminated to communities of interest?One manuscript was recently submitted to a scientific journal, and a second one will be submitted in the near future. What do you plan to do during the next reporting period to accomplish the goals?We will publish two manuscripts on the results described in the previous section.We will also complete Objective 4 and prepare a cost estimate and life cycle assessment of the best performing phosphorus uptake materials.
Impacts
What was accomplished under these goals?
World reserves of phosphorus, an element essential for food production, are limited, posing concerns for sustainable and affordable food production. In addition, current agricultural practices result in significant loss of phosphorus to the environment from animal wastes. This project is investigating sustainable processes for recovering phosphorus from animal wastewaters using materials derived from low-cost agricultural wastes, then reapplying the collected phosphorus as an effective, low-cost fertilizer. The potential benefits are two-fold: recovery and reuse of a limited resource, and reduction of adverse environmental impacts from phosphorus loss to the environment. During this reporting period, we completed Objectives 1 and 3. In addition to previously reported results for Objective 1, during this reporting period we conducted additional measurement of phosphorus uptake by magnesium amended corn cob char and magnesium silicate prepared from rice straw using a range of model wastewater compositions. Specifically, we varied the ammonium to phosphorus ratio in the model wastewater, and measured its impact on the concentrations of dissolved phosphorus remaining at equilibrium. We found that as the amount of added ammonium chloride increased, equilibrium dissolved phosphorus concentrations decreased. This was explained by chemical equilibrium modeling, which showed that increasing concentrations of chloride (added as ammonium chloride) served to extract Mg2+ from magnesium phosphate complexes, freeing the phosphate to precipitate as struvite. The results indicate that the ionic composition of the wastewater strongly influences dissolved phosphate speciation, and that changes in wastewater composition can significantly affect the recoverable phosphorus, as well as the concentrations of dissolved phosphorus remaining in solution after treatment. This is important because seawater and bittern (partially evaporated seawater), which have different ionic compositions and concentrations of chloride relative to other dissolved constituents, have both been proposed as sources of magnesium for struvite precipitation from wastewaters. During this reporting period, we also finished Objective 3. The best performing materials from Objectives 1 and 2 were selected for Objective 3 phosphorus release experiments in flow through columns. Two samples of corn cob biochar--one amended with Mg(OH)2(s), and one amended with model bittern (a residue of seawater evaporation containing magnesium and calcium)--were studied, along with calcium silicate hydrate made from rice husks and hydrated lime. After exposure to model wastewaters containing high concentrations of phosphorus, these spent materials were mixed with sand in soil columns and the release of phosphorus was monitored at pH 5.5, 7.0, and 8.5, both with and without the addition of iron oxide (goethite) and clay (kaolinite) amendments. In columns containing sand and spent magnesium chars, and no goethite or kaolinite, there was relatively fast and complete release of phosphorus. Release was slower and effluent concentrations were lower for calcium silicate hydrate compared to the magnesium char due to lower solubility. When kaolinite and goethite were added to sand columns, a significant fraction of phosphorus was retained in the column, especially for goethite, which would necessitate addition of a greater quantity of spent magnesium char in iron rich soils.
Publications
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Progress 03/15/20 to 03/14/21
Outputs
Target Audience:The target audience of the efforts during this reporting period is the research and science community. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?One graduate student completed her M.S. degree in the fall 2020 semester. A second graduate student has completed three years of Ph.D. study. How have the results been disseminated to communities of interest?The two graduate students working on this project presented their results to the research community at the OU International WaTER Conference, Norman, Oklahoma, Sept. 16-17, 2019. The PI presented the results at the AFRI Foundational Program Agroecosystems Meeting, USDA-NIFA, January 12th-14th, 2021. Two papers were published in scientific journals. What do you plan to do during the next reporting period to accomplish the goals?First, we will follow up on preliminary results from this year and identify the proportions of ammonia, magnesium, and phosphorus in model wastewaters that maximize phosphorus uptake, and further test lower cost sources of magnesium and calcium for synthesis of sorbent materials, such as model sea water, lime, and magnesium oxide and hydroxide. In addition, we expect to complete Objective3 and test phosphorus release form spent calcium and magnesium minerals in model soils in flow through systems at different pH values to test the effects of soil constituents (clay, iron oxides) and pH on phosphorus release. We will also complete Objective 4 and prepare a cost estimate and life cycle assessment of the best performing phosphorus uptake materials.
Impacts
What was accomplished under these goals?
World reserves of phosphorus, an element essential for food production, are limited, posing concerns for sustainable and affordable food production. In addition, current agricultural practices result in significant loss of phosphorus to the environment from animal wastes. This project is investigating sustainable processes for recovering phosphorus from animal wastewaters using materials derived from low-cost agricultural wastes, then reapplying the collected phosphorus as an effective, low-cost fertilizer. The potential benefits are two-fold: recovery and reuse of a limited resource, and reduction of adverse environmental impacts from phosphorus loss to the environment. During this reporting period, we completed Objectives 1, 2 and part of Objective 3. Specifically, we found that magnesium-amended corn cob biochar and magnesium silicate, synthesized using rice straw as a silicon source, were effective at phosphorus uptake from model animal wastewaters through formation of the mineral struvite (MgNH4PO4ยท6H2O) (Objective 1). In addition, calcium silicate hydrate was prepared using rice husk as a silicon source and used to recover phosphorus from model animal wastewaters, forming a non-crystalline calcium phosphate mineral (Objective 2). After phosphorus uptake, the spent sorbent materials were tested for phosphorus release using modified soil tests representing different soil pH and alkalinity conditions (Objective 3). For spent magnesium-amended char and magnesium silicate, the best phosphorus release was under mildly alkaline conditions. For spent calcium silicate hydrate, the best phosphorus release was under acid and neutral conditions. For all phosphorus uptake materials, high alkalinity values interfered with phosphorus uptake, most likely through competition of bicarbonate with phosphate for available dissolved calcium. However, a moderate level of alkalinity (approximately 300 mg/L as CaCO3) was found to have no significant detrimental impact on phosphorus uptake by calcium silicate hydrate made from rice straw. These results show that agricultural biomass such as corn cobs, rice straw, and rice husks can be diverted from a waste stream to a beneficial use for preparing low-cost sorbent materials for phosphorus uptake. Furthermore, these phosphorus uptake materials are effective in phosphate removal from model animal wastewaters, even at moderate levels of alkalinity, indicating that they show promise as a realistic treatment alternative. Finally, preliminary results indicate that spent phosphate uptake materials made from agricultural wastes can release the sorbed phosphorus at pH values found in soils, and could potentially serve as a renewable source of phosphorus fertilizer.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Sharmin, N., Sabatini, D. A., Butler, E. C. (2021), Phosphorus recovery and reuse using calcium-silicate hydrate made from rice husk, Journal of Environmental Engineering 147(6), 04021015, DOI: 10.1061/(ASCE)EE.1943-7870.0001877.
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Ding, Y., Sabatini, D. A., Butler, E. C. (2021), Phosphorus recovery and recycling from model animal wastewaters using materials prepared from rice straw and corn cobs, Water Science and Technology 83 (8), 1893-1906, DOI: 10.2166/wst.2021.094.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2021
Citation:
Butler, E. C., Nutrient Cycles and Management: Closing the Loop on Phosphorus Management with Waste Derived Materials for Phosphorus Recovery and Reuse, AFRI Foundational Program Agroecosystems Meeting, USDA-NIFA, January 12th-14th, 2021.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Sharmin, N., Sabatini, D., Butler, E., Phosphate recovery from wastewater using calcium silicate hydrate: an adsorbent made from rice husk and rice straw, University of Oklahoma International WaTER Conference, Norman, Oklahoma, Sept. 16-17, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Ding, Y., Sabatini, D., Butler, E., Preparation, characterization, and performance of magnesium loaded biochars for phosphate uptake from manure wastewater, University of Oklahoma International WaTER Conference, Norman, Oklahoma, Sept. 16-17, 2019.
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Progress 03/15/19 to 03/14/20
Outputs
Target Audience:The target audience of the efforts during this reporting period is the research and science community. Changes/Problems:No changes/problems. What opportunities for training and professional development has the project provided?One graduate student is nearing the end of her MS training (she will complete her degree requirements in the Fall 2020 semester). A second graduate student has completed two years of PhD study. How have the results been disseminated to communities of interest?The two graduate students working on this projectpresented their results to the research community at theOU International WaTER Conference, Norman, Oklahoma, Sept. 16-17, 2019. What do you plan to do during the next reporting period to accomplish the goals?We will complete submit and publish our first papers on phosphate uptake and release by magnesium silicate, magnesium amended char, and calcium silicate hydrate. In addition, we will complete one remainingpart of Objective 2, which is phosphate uptake by bassanite made from crushed cow bones. We will also complete preliminary cost analyses and life cycle assessment of these materials (Task 4), and start more detailed phosphate release experiments under flow through conditions (Task 3).
Impacts
What was accomplished under these goals?
During the last year, we have continued work on Objectives 1 and 2, and are preparing two manuscripts for publication to be submitted this summer.The manuscripts will address the impact of wastewater alkalinity on phosphate uptake by magnesium silicate, magnesium amended char, and calcium silicate hydrate, all made from plant wastes (corn cobs, wheat straw, and rice husks, respectively). In some cases, we have characterized the phosphate minerals formed upon uptake from model wastewaters using X-ray diffraction. We have also started Task 3 by studying phosphate release by the spent magnesium silicate, magnesium amended char, and calcium silicate hydrate (i.e., after phosphate uptake), using the Mehlic 3, Bray P1, and Olsen tests of bioavailable phosphorus, in order to model phosphate release under different soil conditions.
Publications
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Progress 03/15/18 to 03/14/19
Outputs
Target Audience:The target audience of the efforts during this reporting period is the research and science community. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate students (one M.S. and one Ph.D.) have had the opportunity to carry out individual research as part of their graduate program. How have the results been disseminated to communities of interest?Journal papers are in preparation, and abstracts have been submitted to a conference (the 2019 OU International WaTER Conference (http://www.ou.edu/coe/centers/water/conference1/2019_Conference)), to be held in September 2019. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, we expect to complete Objectives 1 and 2 and begin work on Objectives 3 and 4. Specifically, upon completion of Objectives 1 and 2, we expect to have (1) identified straightforward preparation methods for phosphate uptake materials using agricultural wastes (corn cobs, rice husks, rice straw, wheat straw, and others), (2) characterized these materials, and (3) determined the maximum phosphate uptake under relevant treatment conditions (e.g., pH, solids loading, wastewater composition). During the next reporting period, we also expect to make at least two conference presentations, and submit two papers for publication.
Impacts
What was accomplished under these goals?
During this reporting period, we have made progress on Objectives 1 and 2. Specifically, we have synthesized magnesium-amended corn cob char and tested it for phosphorus uptake (Objective 1). We have also prepared calcium silicate hydrate (CSH) using silica from rice husk ash and rice stalk ash, and tested this CSH for phosphate uptake. We have determined that phoshphate uptake by CSH is dependent on pH, and appears to be removed at least in part by precipitation as a calcium phosphate mineral (Objective 2). These materials were synthesized in part from agricultural wastes and show promise for uptake and recovery of phosphorus from animal wastewaters. Our results to date help to clarify the mechanisms of phosphate uptake, which will be important in applying this technology in the future.
Publications
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