History

A successful 10 years in improving water quality and enhancing wetlands

     Wetlands have been used to treat wastewater for centuries, but only in the past several decades has the response to such use been scientifically analyzed in a comprehensive way. The ability of wetlands to perform certain water purification functions has been well established for natural wetlands. Studies directed by Dr. John Day, Jr. have shown that wetlands chemically, physically, and biologically remove pollutants, sediments and nutrients from water flowing through them.

     Two major environmental problems currently affecting Louisiana are a high rate of coastal wetland loss and high levels of surface water pollution. The application of secondarily-treated wastewater to wetlands could address both of these problems. The benefits of wetland assimilation of treated effluent include improved surface water quality in receiving streams, increased accretion rates to balance subsidence, improved plant productivity, and decreased capital outlays for conventional engineering treatment systems. Wetland assimilation projects can be designed and operated to restore deteriorating wetlands to previous levels of productivity.

     Three early studies looking at Zapp’s Potato Chips, Inc., the City of Thibodaux and the City of Breaux Bridge, by Dr. Day pointed the way to addressing water quality and wetland loss. These studies demonstrate how science working with nature can provide innovative cost effective approaches to treating wastewater effluent.

     In 1985, Zapp's Potato Chip Factory began discharging effluent to a bottomland hardwood swamp located in Gramercy, Louisiana. The discharge site had been partially impounded during the previous 30-40 years by the construction of a highway, a road, a canal, and an underground pipeline. Consequently, the receiving wetland had been isolated, to some extent, from the larger forested wetland system surrounding Lake Maurepas. The isolated area retained some forms of its original woody vegetation while also providing conditions conducive to the establishment of more herbaceous types of vegetation. Results of an extensive study by Dr. Day indicated that the productive ridge area could be used to assimilate the effluent load.

     The second study, of Thibodaux, looked at a municipal situation. In 1985 Thibodaux was charged with violation of its NPDES permit to discharge in the Lafourche drainage canal. As a result over $2.8 million was spent to upgrade the 4 MGD secondary treatment system, which now achieves less than 20 mg/l BOD and 20 mg/l TSS, and a minimum of 5 mg/l dissolved oxygen.

     In 1988, coastal ecologist, Dr. John W. Day, Jr., in association with Louisiana State University, began to work with the City of Thibodaux to determine the effects of introducing treated municipal effluent to wetlands. Dr. Day proposed a comprehensive study to quantify the potential for the use of wetlands for wastewater assimilation in South Louisiana. Such an approach could achieve both improved water quality and enhanced wetlands while at the same time saving money and energy.

     As an alternative to sand filtration, the Department of Environmental Quality (DEQ) and the U.S. Environmental Protection Agency (EPA) allowed the city to participate in a pilot project designed to measure the potentially beneficial effects of the effluent on a local cypress-tupelo and bottomland hardwood swamp formerly flooded by the Lafourche Bayou. Discharge of the City's secondary effluent to the swamp began in February of 1992. A two-year baseline study of the swamp was designed and implemented prior to initiation of effluent discharge. Over the next two years, monitoring data was collected to accomplish three primary objectives: 1) to determine the fate of toxins and pathogens including coliforms and priority pollutants, 2) to determine the impact of the effluent on floral and faunal communities, and 3) to determine the impact of the effluent on nitrogen, phosphorus, and carbon cycles.

     Two years of baseline data were collected at the Thibodaux study site beginning in October 1988. Complete assimilation of nitrogen and phosphorus from the effluent was expected. These rates confirmed the expectation that Louisiana wetlands can provide a permanent sink for added nutrients.

     The objective was to investigate the beneficial use of treated wastewater effluent in South Louisiana to achieve both wetland enhancement and water quality improvement. The overall study included a comprehensive plan for wastewater treatment including both point and non-point source pollution. The study considered what role wetlands, both constructed and natural as well as buffer strips can play in achieving water quality goals. The use of conventional and innovative sewage treatment systems to interface with wetlands was considered.

     In addition to improvement of water quality, the benefits of a comprehensive program were to support ecosystem restoration, propagation of fish and wildlife, combating saltwater intrusion, enhancing accretion to offset sea level rise, and sequestration of carbon. In addition, from a socio-economic point of view, the program would result in substantial economic and energy savings.

     In the study Dr. Day documented nutrient and sediment yield for point and non-point sources from agriculture, municipalities, sea food processors and industry as well as urban runoff. He identified both volume and concentration of wastewater flows and determined total yields.

     In the third instance, Dr. Day worked with the town of Breaux Bridge. Since the 1950's the town has been discharging its wastewater into an adjacent cypress-tupelo and bottomland hardwood swamp approximately 20 meters from the treatment area. A trickling filter was constructed in the 1950's and was replaced by a total of three oxidation ponds built in the 1970's and 1980's. The town is not currently discharging into a surface water body, but the situation provides a unique opportunity to analyze the effects of municipal wastewater application to wetlands over approximately 40 years. Consequently, the discharger criterion that effluent be discharged to a surface water body was waived in the selection of Breaux Bridge, but the second criterion of non-toxic municipal effluent is met. The major benefit of this potential pilot study site is the opportunity to gain information on the long-term nature of sewage effluent application.

     EPA has recently required the town to upgrade its treatment plant from its current discharge of approximately 30 mg/l BOD and 30-35 mg/l TSS to 10 BOD and 15 TSS. The lower 10/15 limits are those designed to maintain a dissolved oxygen content of 5 mg/l in flowing streams, and do not consider the health or assimilative capacities of wetland ecosystems.

     Based on intensive scientific analysis Dr. Day found that the Breaux Bridge swamp may have benefited from the effluent load over the past 30 years. Moreover, spending $1.5 million estimated to upgrade the existing treatment system may be an unnecessary expense and even detrimental to the wetland if the added sediments and nutrients have increased vegetative productivity and stimulated accretion.

     Wetlands were characterized for the potential to receive wastewater. The size, type and ecology of the receiving wetlands along with a documentation of conflicting uses were identified. Natural wetlands, constructed wetlands and buffer strips were determined.

     Wastewater flows were matched to wetland assimilative capacity. The relationships among loading rate, residence time and assimilation for natural wetlands, buffer strips, and constructed wetlands were calculated.

     The study included an economic analysis of wetland assimilation to document the cost savings of using this approach. This focused on operating costs such as chemicals, land and energy expenditures. It also evaluated energy and economic savings. The potential for use of alternative energy sources, such as solar, in the operation of the system was investigated.

     With this research background Dr. Day and Joel Lindsey, in 1998, formed a joint venture, Comite Resources, Inc., to take this innovative technology to other municipalities and food processors. Each arrived at his interest in wetlands through a different route, but when they talked their ideas of the role of wetland assimilation meshed and they began to seek a common vision. Dr. Day was a wetland ecologist who believed science was the key to human betterment. Lindsey, former Deputy Secretary of the Louisiana Department of Environmental Quality and Administrator of Coastal Zone Management, combined a more practical approach to science and innovative solutions to wetland loss; he came to recognize that environmental regulations were only part of the solution to stemming coastal wetland loss and improving water quality.

     In 1998 they completed a wetland assimilation feasibility study for Ascension Parish. This study examined 6 potential receiving sites for the discharge of treated effluent. The sites included Bluff Swamp, St. Amant Swamp, Cocodrie Bayou, Lake Martin, McElroy NW and McElroy SE.

     In 1999 Comite Resources, Inc. successfully secured a wetland discharge permit from the Louisiana Department of Environmental Quality (DEQ) for St. Bernard Parish’s Riverbend oxidation pond.

     In the same year St. Charles Parish approached Comite Resources, Inc. to investigate the feasibility of discharging their secondarily treated effluent from the Luling Pond to adjacent wetlands. The wetlands in the vicinity of the Luling Pond are composed of freshwater forested wetlands and fresh and intermediate marshes. Because these wetlands are isolated from the Mississippi River, there is inadequate sediment input and vertical accretion. Wetland discharge will lead to an increase in accretion. Water bodies in the vicinity of Luling Pond were generally in a eutrophic state and in the next 3-5 years, it is expected that DEQ will lower the allowable concentrations for nitrogen and phosphorus and, in the future, water quality standards will become more stringent. The current treatment level of the Luling Pond would not meet more stringent standards. Implementation of a wetland discharge program would result in substantial nutrient reductions, which will allow the Parish to meet these newer standards. Based on the results of the study it was recommended that St. Charles Parish approach DEQ and EPA and consider carrying out a Use Attainability Analysis (UAA) as the next step to adoption of wetland assimilation at the Luling Pond. Comite Resources, Inc. successfully completed the UAA in 2005.

     St. Charles Parish commissioned Comite Resources, Inc. to secure the wetland discharge permit and 404 permit. Comite worked with the regulatory agencies to establish permit standards. The parish began discharging to the Luling swamp in 2006. St. Charles Parish selected Comite Resources to conduct the multi-year biological monitoring required by the DEQ and EPA.

     In 2000 Comite Resources, Inc. began multi-year biological monitoring projects for the City of Thibodaux and Breaux Bridge, Louisiana. As part of the conditions of permits, the cities are required to carry out monitoring of the ecology and chemistry of the wastewater effluent and the receiving forested wetland. The overall objective of these projects is to carry out measurements to specifically meet the requirements of the permits. . Results of the monitoring reports showed that there were no measurable detrimental effects of the discharge and that the discharge enhanced the productivity of the swamp forest, increased accretion, and substantially improved water quality.

     Based on Dr. Day’s research the City of Mandeville engaged Comite Resources, Inc. to secure a wetland discharge permit to the Chinchuba swamps and the Tchefuncta East Marsh for their treated effluent. The average flow per day ranges from 1.4 MGD to 2 MGD. After extensive discussions with landowners and the regulatory agencies the permit was issued in 2003. Subsequently, the city selected Comite Resources, Inc. to conduct the biological monitoring required by the DEQ and EPA.

     Impressed with Comite’s many successful wetland assimilation projects, the US Environmental Agency and Louisiana Department of Environmental Quality approached Comite to conduct a preliminary analysis to determine the feasibility of the application of effluent to Louisiana wetlands. In 2006 Comite assisted the regulatory agency in two workshops (Thibodaux and Lake Charles). Dr. Day presented case studies on completed wetland wastewater assimilation projects.

     In addition, Comite conducted 9-wetland assimilation studies in Louisiana. These studies evaluated wetlands in proximity of interested municipalities. A site visit was conducted to potential receiving wetlands. The wetlands were characterized as to their ecological condition and capacity to assimilate treated effluent. Baseline data was collected on vegetation species composition and hydrology. Comite determined the presence of federally or state listed threatened or endangered species and wetland ownership. Comite also interviewed city and parish public works directors and engineers on owners of potential wetland sites and provided data on the municipal wastewater treatment plant processes. These projects were completed in 2006.

     In 2002, the City of St. Martinville, LA contracted with Comite Resources, Inc. to investigate the feasibility of discharging secondarily treated effluent from their oxidation pond facility to adjacent wetlands. The wetlands in the vicinity of the proposed pond are composed of freshwater-forested wetlands.

     Water bodies in the vicinity of St. Martinville are generally in a eutrophic state and in the next 3-5 years, it is expected that Louisiana Department of Environmental Quality (LDEQ) will lower the allowable concentrations for nitrogen and phosphorus and, in the future, water quality standards will become more stringent. The current treatment level of St. Martinville will not meet more stringent standards. The forested wetlands to the west and northwest of the oxidation ponds are sufficient to assimilate the discharge of treated effluent.

     Implementation of a wetland discharge program will result in substantial nutrient reductions, which will allow St. Martinville to meet these newer standards. Wetland assimilation will provide the most economical approach for St. Martinville to meet its water quality objectives. A Wetland Assimilation Feasibility Study was completed in 2002.

     An Ecological Baseline Study was finished in 2004. This study included water quality analysis, sediment characterization, vegetation composition, hydrology, and productivity analysis. A nutrient loading rate analysis indicates that the forested wetlands will assimilate most nutrients discharged from the St. Martinville wastewater treatment facility. It is also expected that the productivity of the swamp forest will be enhanced and oxidation of the soil reversed. The overall results of the study indicate that the use of the Cypress Island Coulee wetlands for wastewater assimilation will be a long-term solution for treatment of effluent from the St. Martinville wastewater treatment facility.

     Comite Resources, Inc. worked with the US Army Corps of Engineers, DEQ and EPA to secure St. Martinville’s permits. The permit process was completed in 2008.

     Comite Resources, Inc. teamed with scientist and engineers in a successful proposal to the Orleans Sewage and Water Board and St. Bernard Parish to conduct wetland feasibility study on the Central Wetlands Unit (CWU) encompassing over 30,000 acres, primarily within St. Bernard Parish. This particular area was once a healthy bald cypress and water tupelo swamp that has been severely degraded over the last several decades, most notably by the construction of the Mississippi River Gulf Outlet (MRGO), which provided a direct channel for higher salinity waters to move inland from the Gulf of Mexico.

     A significant effort was undertaken to assess the current condition of the CWU, specifically aimed at calculating effluent loading rates to the wetlands. This is always important in these types of projects to ensure that the design flows into the wetlands are sufficient to provide the level of nutrients required for restoration while not overloading the system’s assimilative capacity.

     Comite Resources, Inc., Inc. has recommended to the Sewage and Water Board that the next phase of the study include engineering and detailed design of the distribution system to continue the development of a plan to improve water quality and enhance wetlands.

     In 2002 the City of Hammond asked Comite Resources, Inc. to investigate the feasibility of discharging their secondarily treated effluent from an oxidation pond facility to the Joyce Wildlife Management Area wetlands. The wetlands are located in the northwest corner of the Management Area, below the City of Ponchatoula.

     Water bodies in the vicinity of Hammond are generally in a eutrophic state and in the next 3-5 years, it is expected that the regulatory agencies will lower the allowable concentrations for nitrogen and phosphorus and, in the future, water quality standards will become more stringent. The current treatment level of Hammond did not meet more stringent standards.

     Following completion of the feasibility study Hammond engaged Comite to conduct a twelve-month ecological baseline study. This study included water chemistry analysis, hydrology, sediment characterization, vegetation composition, and primary productivity analysis. There are two types of wetlands in the study area: forested swamps and emergent marshes, which required differing methods to determine plant composition and productivity.

     Nutrient loading rate analysis indicates that the South Slough wetlands and JWMA wetlands will assimilate 85 percent to 99 percent of nitrogen and phosphorus discharged from Hammond’s wastewater treatment facilities. It is also expected that the productivity of the wetlands will be enhanced and that saltwater intrusion will be reduced. It is likely that there will be an increased area of cattails and willows, but that this will be limited to the South Slough wetlands. The overall results of the study indicated that the use of the South Slough and JWMA wetlands for wastewater assimilation will be a long-term solution for additional treatment of effluent from the Hammond wastewater treatment facilities.

     Comite successfully secured the Coastal Use Permit (CUP) and wetland discharge permit for this project. Since 2006 Comite conducts the biological monitoring required by the permit.

     In 2007 Comite completed two feasibility studies for La Feria and San Benito in Texas. La Feria proposed to create a Nature Park that includes wetlands to remove nutrients from a portion of the effluent from the new wastewater treatment plant. This analysis included consideration of using about 11 acres of constructed wetlands in the Nature Park, as well as 25 acres of wetlands in the existing oxidation ponds. The estimated discharge from the La Feria wastewater treatment facility is approximately 1.25 million gallons per day (MGD). Loading rate calculations were based on nutrient input and wetland area available in the nature park and in the oxidation ponds. The nature park is proposed to have 11 acres and the total area of the oxidations ponds is 25 acres, thus the total potential wetland assimilation area is 36 acres.

     In 2008 Comite teamed with a group of scientist in Mexico to do a project entitled “Analysis of the Use of Wetlands Regulatory System Lagoon Paramán-Chalacatepec for Rehabilitation” This study is designed to describe the dynamic characterization of the structure and operation of the ecological system. The results of this project will define the approach for handling technology restoration of the system Paramán-Chalacatepec.

     In 2008 Comite completed work on a project for the City of Kenner. Kenner, Louisiana is evaluating options related to the discharge of secondarily-treated municipal effluent into the LaBranche wetlands located west of Kenner, Louisiana. In 1983, the City built a third wastewater treatment plant (WWTP3) to consolidate the discharge from their existing two treatment facilities and re-route flow to WWTP3. Recently, consolidation was completed, but the City now must address how to dispose of sanitary sewer overflow during wet weather events and how to further reduce nutrients in treated effluent. Discharge into the LaBranche wetlands is one solution to this problem that is being considered. Wetland assimilation will provide the most economical approach for the City of Kenner to meet its water quality objectives.

     In addition to providing water quality improvement, the LaBranche wetlands will be greatly enhanced by the addition of treated municipal effluent. These wetlands are currently in a severely degraded state and the addition of nutrients and freshwater via treated effluent will lead to enhanced growth and improvement of degraded habitat, in addition to the future potential for wetland mitigation banking and carbon sequestration banking. The project will also enhance hurricane protection by enhancing wetlands.