Assessment of Non-Anthropogenic Addition of Uric Acid to a Water Treatment Wetlands

Abstract

Artificial water-treatment wetlands can reduce nitrogen and phosphorous nutrient concentrations in wastewater effluent to improve water quality and decrease eutrophication in natural waters. The Orlando Easterly Wetlands (OEW) is an engineered wetland that polishes 57 million liters of wastewater per day, lowering the total nitrogen and phosphorous concentrations through biological, physical, and chemical processes. In addition to purifying the water, the wetlands provide habitat for avian, mammalian, reptilian and macroinvertebrate species. Previous research has shown that avian species affect the eutrophication of agricultural reservoirs near their roost. The research herein quantifies uric acid in avian and reptilian excretory product and tracks its concentration profile throughout the OEW over a seven-month period. This measure of the non-anthropogenic contribution to nitrogen within the park includes winter months when large numbers of migratory birds occupy the wetland. The enzymatic decomposition of uric acid and the subsequent fluorimetric analysis were used to quantify uric acid throughout the flow train of the OEW. High concentrations of 2–4 mg/L uric acid were found in the influent, but drastically declined to concentrations below 0.2 mg/L in the effluent.