Institute: North Dakota
Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-29
Total Federal Funds: $8,292 Total Non-Federal Funds: $16,583
Principal Investigators: Khan Eakalak
Abstract: Wastewater treatment plants (WWTPs) in major cities in North Dakota, such as Fargo and Bismarck, have average and maximum effluent total phosphorus (TP) of approximately 3.5 and 6 mg/L, respectively as reported by operators. Currently there is no limit on P in the state of North Dakota, but nationwide regulations are being proposed to limit effluent TP. Phosphorus is typically found in lower concentrations than nitrogen in water bodies and wastewaters; it is a limiting nutrient for biological growth that can be controlled in effluents. However managing P in water-bodies is a more effective management practice due to certain phytoplankton being capable of fixing nitrogen from the atmosphere into the water-body. While current WWTP regulations are based on TP, studies have shown that only a portion of TP is bioavailable to support the growth of algae. Bioavailable P (BAP) is the sum of immediately available P (IAP) and potentially available P (PAP). IAP is the portion that can be taken up by algae within a few hours, while PAP is the portion transformed, after longer durations, to IAP forms by physical (e.g. desorption), chemical (e.g. dissolution), and/or biological (e.g. enzymatic degradation) processes. Objectives of this study include: 1. to test the bioavailability of P with algae placed individually and together in the same sample, as water bodies contain mixed cultures of organisms, 2. to investigate the effect of enzymatic activity, and 3. to evaluate the effect of UV light on BAP. Results will show whether BAP estimates vary between different algal species. If results vary this research will show that the current standard algal species of R. subcapitata may not necessarily be a reliable species for BAP determination and that other algal species may provide a higher estimate of BAP. This research will lead to reliable estimates of BAP released by WWTPs. It will inform WWTPs on the P-fractions that are contributing to algal blooms, allowing operators to determine which forms of P to focus on removing during treatment.