Luling Pond Wetland Assimilation Ecological Baseline Study (EBS)

LDEQ and USEPA issue permit limits of 30 BOD and 90 TSS

     St. Charles Parish's Director of Public Works, came to Comite Resources, Inc. early in 1998 asking for a wetland assimilation feasibility study near Luling Pond. Together a Pre-Ecological Baseline Study was completed a to evaluate the discharge of treated domestic wastewater into nearby wetlands. In 2001, St. Charles Parish and Comite Resources, Inc. began working on a year long study to collect and analyze biological and chemical data for the Luling Pond wetlands. This 12 month Ecological Baseline Study (formally called Use Attainability Analysis (UAA) provided environmental information for a wastewater discharge application and forms the basis for the permit conditions. Comite Resources, Inc. completed the Luling Wetland Wastewater Assimilation EBS in 2003. The study included water chemistry analysis, characterization of sediment, and vegetation composition and productivity analysis. Boardwalk construction was completed to provide access and protect the sampling sites. One control (C) and three treatment locations (T1, T2, and T3), with two replicate plots at each location, were established. Vegetation within the plots was identified and DBH of each tree was measured in 2002 and 2003. Bulk density of the sediment as well as pH, temperature, dissolved oxygen, salinity, and conductivity of the water were also determined. This area is a characteristic coastal swamp forest with permanent inundation and organic surface sediments.

     The vegetation was dominated by baldcypress and water tupelo with a small amount of red maple. Nitrogen in the surface water was dominated by NH4, consistent with the low dissolved oxygen contents. Iron is the most prevalent soil metal constituent, followed by magnesium, sodium, and manganese. Overall, the control and treatment plots are similar. Loading rate analysis indicates that the forested wetlands will assimilate most nutrients in the secondarily treated effluent from the Luling oxidation pond. It is also expected that the productivity of the swamp forest will be enhanced. The overall results of the study indicate that the use of the forested wetlands for assimilation of secondarily-treated effluent will be a long-term solution for the discharge of this effluent from the Luling oxidation pond. In 2008 LDEQ and USEAP issued a permit to St. Charles Parish for effluents limits of 30 mg/l BOD and 90 mg/l TSS. St. Charles Parish is in the southeastern part of Louisiana, about 24 miles west of New Orleans. The total land area is 193,302 acres and 93,389 acres is large area water bodies in the form of streams and lakes. Lake Pontchartrain borders the parish on the north, Lafourch Parish on the south, Jefferson Parish on the east, and St. John the Baptist Parish on the west. The discharge point for Luling Pond is located at Longitude -90..36137 0 and Latitude 29.878850 or 1.85 miles south of U.S. Highway 190, 4.85 miles northeast of Lake Cataouatche and adjacent to Cousin Canal on the east. Potential wetland sites are in the southern portion of St. Charles Parish.

Luling Pond Wastewater Assimilation

     Parish leaders saw the EBS as a way to gather scientific data on the feasibility of using wetlands to assimilate treated effluent. They knew the biological data resulting from this EBS would be used by the Louisiana Department of Environmental Quality (LDEQ) and the US Environmental Protection Agency (EPA) to evaluate the permit application and set permit conditions. Permit conditions are based on biological criteria established in the EBS.

     Environmental monitoring tracks biological and chemical parameters to ensure current wetland uses are not degraded. Based on scientific data from other wetland wastewater assimilation projects in Louisiana the Luling Pond project will improve water quality and enhance wetlands.

     People living in St. Charles Parish have a lot to think about, meeting state and federal water quality regulations, construction cost, maintenance expenses and operation cost. Comite Resources, Inc. used 24 years of scientific research to design a wetland wastewater management system to meet regulatory requirements, improve water quality, enhance wetlands, and reduce construction cost, maintenance expenses and energy consumption.

     For example, the use of forested wetlands as essentially tertiary treatment systems can be viewed as a means of fertilization as well as a way to achieve clean water. Several studies have investigated the processes of nutrient transformations as well as the capacity of forested wetlands to remove excess nutrients, especially nitrogen and phosphorus.

     Other studies have focused on the response of forested wetlands to nutrient addition. Researchers have shown that litter fall, biomass, and net primary productivity can be enhanced with addition of nutrients. For example, tree productivity in a forested wetland in Wildwood, Florida, was enhanced by the addition of wastewater. A cypress dome in Florida receiving sewage discharge also showed a significant increase in net primary productivity, litter fall and wood production in comparison with untreated cypress domes.

Changes in elevation, hydrology, and nutrient

     The addition of treated effluent discharge into forested wetlands may indirectly affect forest species composition and forest structure by causing changes in elevation, hydrology, and nutrient status. By inducing accretion through the deposition of suspended solids, wastewater application can indirectly affect species composition.

     The amount and timing of the effluent discharge can also be important factors controlling changes in forest dynamics. With low nutrient loading rates, wetlands may be able to remove much of the phosphorus applied, and the phosphorus retention capacity will continue for many years. At high loading rates, the ability of wetlands to remove nutrients decreases.

     Such a complicated project reflects Comite Resources, Inc. multidisciplinary approach to wetland assimilation of treated effluent. Comite Resources brings together strategic thinking and analysis, creative design, technical architecture, and user experience to define a wetland assimilation management strategy for St. Charles Parish.

     "We are proud of the value we give our customers in a short time frame. It is a challenge, but not only did we come through as a multidisciplinary team, we've come through as individuals with multidisciplinary skills," commented Dr. John W. Day, Comite Resources, Inc..

     Luling Pond and wetland assimilation project is an elegant solution that will deliver low cost benefits to citizens and positions St. Charles to improve water quality and enhance wetlands.

     Wastewater management? Environmental compliance? Turn to Comite Resources, Inc. for the solution. Contact us for more information.