The City of West Monroe Sparta Reuse Facility Efforts to Save the Sparta Aquifer
Terry Emory, City of West Monroe, 303 West Pavilion Drive, West Monroe, Louisiana, 71292: emoryterry@yahoo.com
In 1996, city officials in West Monroe noticed an alarming trend: water was being overdrawn from the Sparta Aquifer by eighteen million gallons per day (18MGD) beyond the recharge rate and if this trend was not reversed, Ouachita Parish and sixteen (16) other parishes in Northeast Louisiana would lose their source of fresh water for potable water consumption, agriculture and industry. The Sparta Aquifer is the primary fresh water supply for nearly eight hundred thousand (800,000) people and the industries that employ them. Of three major cones of depression in the aquifer, the most significant was directly under the paper mill in West Monroe. Depletion of freshwater would cause saltwater encroachment and become unusable.
The City owns a wastewater treatment facility that provides service to approximately forty-five thousand (45,000) people: the City and West Ouachita Sewer District #5, and discharged an annual average of seven million gallons per day (7MGD). The goal was to provide quality process water to the largest user of the aquifer which was the local paper mill, Graphic Packaging. The mill used ten million gallons per day (10 MGD) from each, the aquifer and the Ouachita River. The cost of increasing the draw and treatment of river water to discontinue the draw of well water at the mill could pose economic hardship for the area. After years of research and negotiations, the City built a one million gallon per day (1MGD) pilot plant which was run for one full year to prove that this system could effectively and economically produce water which would meet the requirements of the mill which produces food contact paper. After one full year of treating sewer water with characteristics that change seasonally to drinking water quality that met all Environmental Protection Agency primary and secondary drinking water standards, the mill agreed, by contract, to accept this treated water for use as process water. Also by the terms of the contract, gallon for gallon, the amount of water the City could provide would be equal to the amount of well water that the mill would no longer draw from the aquifer.
The City immediately sought and secured funding to build a twenty million dollar ($20,000,000.00) facility capable of treating ten to twelve million gallons per day (10-12 MGD) of sewer. The process utilizes proven technology in an innovative way to meet all drinking water standards. The process consists of the treated effluent from the existing wastewater plant (one hundred acres of baffled oxidation ponds and rock filters- hydrograph controlled released) then to the new Sparta Reuse Facility. Two organic polymers, cationic and anionic, are used in flocculation of the solids, then to dissolved air flotation (DAF) units where the primarily algae total suspended solids are skimmed from the surface and returned to the oxidation ponds. No sludge is produced in this process. The cleared water from the DAF units is then pumped into pressure vessels containing virgin bituminous activated carbon to remove any total dissolved solids, metals or other contaminants. Water is then pumped into two (2), one hundred thousand (100,000) gallon storage tanks and is disinfected with chlorine. Five million gallons per day (5MGD) is then pumped to the mill for use as process water only. The Sparta facility also uses the water it produces water for backwash of the carbon vessels.
The facility was built and complete in January 2012. We have reduced the draw on the Sparta by five million gallon per day and are negotiating with other sewer districts and communities to add on to the system to achieve the goal of twelve million gallons per day. The benefits are two-fold because we also no longer discharge treated sewer to the river except minimal amounts during extreme weather events. The facility has been recognized with nine national, regional and state awards, most notably from The White House, “Champions of Change” award in 2012.