Currently, the US Environmental Protection Agency primarily regulates the discharge of dissolved nitrogen and phosphorous from wastewater treatment plants in the United States. A recent study has shown that the treated effluent of many plants contains concentrations of dissolved carbon dioxide well above the expected theoretical equilibrium concentration of 0.6 mg/L, indicating that carbon dioxide may have been overlooked as a possible pollutant in receiving waters. For this reason, it is necessary to examine the possible presence of a discharge plume containing high levels of dissolved CO2 downstream from the outfall of a major wastewater treatment plant in Tampa, Florida.

To examine this possibility, discharge data at the Howard F. Curren Advanced Wastewater Treatment Plant was collected over a two-week period and fed into the UM3 submerged discharge model to simulate discharge conditions at peak ebb tide. In all, five separate runs of the model were performed and compared to examine plume rise, spreading rate, average dissolved CO₂ concentration, and plume path. The model predicts that, for this scenario, the plume rises fairly rapidly and is also quickly diluted to near-ambient concentrations of dissolved carbon dioxide within a short distance of being discharged. While this would seem to indicate that the effects of Howard F. Curren on Tampa Bay, in terms of dissolved CO₂, are negligible major limitations of the UM3 model make it difficult to say this with a great deal of certainty.