WETLANDS RESTORATION USING WASTEWATER EFFLUENT IN ST. BERNARD PARISH, LOUISIANA

Wetlands have long been used to assimilate wastewater but only recently has the response to such use been scientifically analyzed in a comprehensive way. St. Bernard Parish, Louisiana wastewater effluent currently flows from an oxidation pond into the Forty-Arpent Canal and is then pumped into the Poydras-Verret wetland. The USEPA has recently imposed effluent standard limits on the oxidation pond effluent that are typical for municipal dischargers but stricter than those currently achieved. Discharge alternatives considered included: 1) pumping of the effluent to the Mississippi River; and, 2) dispersing the effluent directly into the wetland. Wetlands discharge would save the Parish approximately one million dollars compared to Alternative 1. A use attainability analysis was conducted to determine the effect of the effluent on the area.Results of the study indicate that there was little, if any, demonstrable negative impact of the discharge to the wetland. Regular discharge of fresh effluent into the wetland area has resulted in significant restoration to a portion of the cypress swamp. Current and predicted effluent loading rates are within the assimilative capacity of the wetland. Substantial reductions of nutrients occur across the wetland. Water concentrations at the outlet are similar to concentrations in an adjacent canal and a reference wetland. Soil and water sample results indicate no accumulation or toxicity concerns for metals analyzed. A plan for the evaluation of other areas in the Parish for similar application has been developed. Wetlands restoration employing treated wastewater in this case provides an excellent example of resource management---a step towards sustainable development.