Katie Ho was born in Hilo and raised on the Big Island. She graduated from Hawaii Preparatory Academy in 2011 and is looking to pursue a career in environmental science. Her interest in this field stemmed from taking AP Environmental science and her participation with the Energy Lab at her school. She is currently attending the University of Washington but is transferring to Cornell University in the fall. In her free time, she enjoys going to the beach, hiking and spending time with friends and family.
Institution when accepted: University of Washington transferring to Cornell University.
Akamai Project: Potassium Persulfate Oxidation vs. Photo Oxidation: Determining a Method for Evaluating Total Dissolved Nitrogen and Total Dissolved Phosphorus in Various Water Matrices
Project Site: Natural Energy Laboratory of Hawaii Authority (NELHA)
Mentor: Keith Olson
Chemical and photo oxidation methods have been used in water quality labs to deter-mine the concentrations of total dissolved nutrients in water samples. Most studies compare the results of the chemical and the photo oxidation methods in fresh water systems. The purpose of our research conducted at the Natural Energy Lab of Hawaii Authority (NELHA) is to determine and optimize the most accurate and efficient method in evaluating the total dissolved nitrogen (TDN) and the total dissolved phosphorous (TDP) in brackish groundwater and marine samples. We performed a comparison be-tween Standard Method’s SM 4500-NC, the potassium persulfate (K2S2O8) chemical oxidation method, and NELHA’s historical photo oxidation method. In both methods, the TDN/TDP of the oxidized glutamic acid and glycophosphate gravimetric standards were compared. In the SM 4500-NC chemical oxidation method, we prepared the K2S2O8 reagent using the North Temperate Lake Ecological Research recrystallization procedure to remove the NH3 contaminant. The standard samples were then auto-claved for 1 hour in the presence of ammonia-reduced K2S2O8. Actual TDN and TDP concentrations were determined by an Astoria Pacific A2 segmented flow auto-analyzer and were graphed against theoretical nutrient concentration standards. A trend indicated that the higher the theoretical standard, the lower the actual value. Varying concentrations of the K2S2O8 oxidizing reagent will be tested to optimize the chemical oxidation method, while sample time in the photo oxidation apparatus will be modified to optimize the photo oxidation method. This iterative study will determine whether NELHA should transition from the photo oxidation method to the chemical oxi-dation method in their water quality testing.