Engineering Struvite Precipitate Utilizing Ion Binding Peptides

Recycling nitrogen and phosphorous is of growing environmental importance for the agricultural industry. While these are contributing factors to issues such as eutrophication, these limited nutrients can be recovered from wastewater in the form of a nutrient rich fertilizer. Production of struvite, NH₄MgPO₄*6H₂O, a slow release fertilizer has the potential to provide a very feasible and economical solution. This research involves the use of a mixture of salt solutions to mimic natural wastewater levels and test the yield of precipitate at a variety of pH levels. X-ray diffraction and scanning electron microscope were utilized to analyze both composition and structure of precipitated compounds. Baseline composition and percent recoveries were established for a range of pH values, and past literature suggests low purity and recovery at neutral pH. Therefore, affinity peptides will be added to potentially enhance precipitation of struvite. A quartz crystal microbalance has been used to investigate the binding capabilities of a peptide designed to selectively adsorb to phosphate, and eventually an ammonia binding peptide will be tested.