SUSCHEM: CONTROLS ON STRUVITE NEOGENESIS AND REACTIVITY IN ENGINEERED AND GEOCHEMICAL SYSTEMS

Project Details

Description

Technical DescriptionPhosphorus (P) can be recovered from human and agricultural wastes as the mineral struvite (MgNH4PO4·6H2O), which can be used as an alternative to traditional fertilizers. This project addresses the properties and reactivity of struvite when generated from different types of wastes, and as compared to geochemically produced struvite. The goal of the research is to elucidate the overarching conditions and parameters that dictate the physical and chemical properties of struvite, independent of source of neogenesis. Struvite will be precipitated from swine effluent, greenhouse wastewater, and Mono Lake water. The animal and plant wastes are commonly used in engineered systems for struvite recovery, and Mono Lake is a geochemical system with a historical occurrence of struvite. Model solutions, with deionized water as the solvent, will be used to determine the specific controls; i.e. pH, ionic strength, dissolved organics; on the resultant mineral properties. The sorption of trace contaminants such as metals, prevalent in starting solutions, will also be assessed. This is particularly critical because the impact of struvite properties on sorption processes has not been previously determined, and conversely the effect of sorbed impurities on the mineral structure and stability are not known. The research will implement several advanced and innovative techniques, including P XAFS, 31P NMR, 33P radiotracers and TG/DSC-FT-IR, which are transferable to the study of other phosphate minerals. Results from this research can be used to manipulate the properties of struvite in engineered systems, contingent upon waste composition and implemented conditions. The ability to better engineer struvite from wastes will advance the use of struvite fertilizers and encourage the sustainable use of P.Importance for SocietyThe human phosphorus (P) cycle is unsustainable. This is because P is a limited natural resource, the cycling of which is accelerated by human activity due to its use as fertilizer. With diminishing geologic P reserves, and an ever increasing global population, P lost in the human cycle needs to be recouped. This can be achieved by the recovery of P from human and agricultural wastes as the phosphate mineral struvite. The use of recovered struvite as an alternative fertilizer source will promote the sustainable use of P, conserve natural P resources, and limit the release of additional P sequestered in rocks to the human cycle. This project will provide an improved understanding of the physical and chemical properties of struvite when generated from a variety of sources, including animal and plant wastes. Results can be used to predict, and potentially control, the properties and contaminant content of recovered struvite based on wastewater composition and recovery conditions. This provides the security that struvite delivered to soils as fertilizer can function as required and does not pose a contamination risk, and thus an environmental liability to soils, agro-ecosystems and geochemical systems. Ultimately, the reuse of struvite recovered from wastes as a source of P will introduce sustainability to the human P cycle by providing an alternative, sustainable fertilizer to feed a growing global population.
StatusFinished
Effective start/end date1/2/154/30/16

Funding

  • National Science Foundation (National Science Foundation (NSF))

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