Amelia, LA

The St. Mary Parish Water & Sewage

     The St. Mary Parish Water & Sewer District #1 hired Comite Resources, Inc., Inc. to conduct a year long study to investigate the ecological feasibility of incorporating the Ramos forested wetland as part of its treatment system to polish secondarily-treated effluent. The study area consisted of a bald cypress/bottomland hardwood forest in St. Mary Parish about 2 km (1.25 miles) north of Amelia, Louisiana. The original wastewater treatment system consisted of three oxidation ponds (33 acres) located north of the city. The minimal area evaluated for assimilation of secondarily-treated effluent was approximately 50 ha (120 acres) with a total basin of 1,012 ha (2,500 acres) available. The wetland area is privately owned. The wetland surrounding the oxidation ponds is predominantly bald cypress (Taxodium distichum) and tupelo (Nyssa aquatica), and the dominant species at the lake sites are also bald cypress and tupelo, but maple (Acer rubrum) and ash (Fraxinus pennsylvanica) are also present.

     Hydrologic inputs to the wetland include precipitation, drainage from the natural levee, and backwater flooding from Lake Palourde. The assimilation area receives an additional 1.89 to 3.79 liters per day (0.5 to 1.0 million gallons) from the oxidation ponds. Water is discharged from the northeastern corner of the oxidation ponds and flows along the northern side of the oxidation ponds for approximately 300 m until it reaches the T1 site. The water then spreads out into the wetland in a northern direction, flowing approximately 600 m (0.4 mile) and eventually entering Lake Palourde.

     Effluent from this treatment system flowed into the same general area of the forested wetland since the onset of treatment at the site, or for about 23 years. Currently, the Amelia system is operating under final effluent limits established on June 1, 1995. Productivity as expressed in mean litterfall for one year, was significantly higher in the treatment site than in the control site.