Assimilation and Removal of Phosphorus within the Marshland Upwelling System
The marshland upwelling system (MUS) is an alternative onsite wastewater system that was developed to treat domestic wastewater derived from coastal communities. Previous studies have researched the systems ability to treat fecal coliforms and nitrogen. The objectives of this research were to (1) assess the treatment efficiency of the MUS for removing both total phosphorus and orthophosphate, (2) provide preliminary design and operational guidelines for phosphorus removal, and (3) develop a parameter to project longevity of the MUS for treating phosphorus.
Performance efficiency was compared for a system which operated for 23 months located in Bayou Segnette State Park and that of a system which operated for 12 months in Moss Point, Mississippi. These two systems offered an investigation of MUS performance under low (Bayou Segnette MUS) and high (Moss Point MUS) background salinity conditions. An injection flowrate of 1.9 L/min at an injection frequency of 30 min/hr was used during the final study of the Bayou Segnette MUS. Total phosphorus surface concentrations were estimated to be 0.67 mg-P/L at the conclusion of this study. Research of the Moss Point system concluded with a flow regime of 2.8 L/min with an injection frequency of 15 min/hr. At the conclusion of this study, the predicted surface concentration for total phosphorus was 0.87 mg-P/L.
Batch adsorption laboratory studies were conducted to develop isotherm coefficients for each of the subsurface soils found in these two systems. These studies were also conducted to investigate the impact which salinity would have on phosphate adsorption within the MUS. Freundlich coefficients ranged from 15.2 to 92.8 mg P/kg soil and were shown to be dependent on soil and salinity of the sample. Phosphate adsorption was shown to be slightly enhanced with and increase in salinity. However, the capacity of phosphate adsorption seemed to mostly dependent on the amount of Al, Ca and Fe contained within the soil of the MUS.
Advisor:Robert Gambrell; Clinton Willson; Kelly Rusch
School:Louisiana State University in Shreveport
School Location:USA - Louisiana
Source Type:Master's Thesis
Keywords:civil environmental engineering
Date of Publication:04/06/2005