City of West Monroe Wastewater Treatment Plant - Executive Summary |
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The City of West Monroe is fully committed to chemical safety at our wastewater treatment plant. In order to achieve this we have developed operating procedures, an emergency operating and response program, and continuing training for our operators. The West Monroe Wastewater Treatment Plant is located in a somewhat isolated area south of West Monroe, Louisiana. The plant is bordered on the north by a wooded area, to the east by papermill wastewater treatment ponds, to the south by a wooded area, and to the west by a wooded area followed by a flood control levee protecting a residential area. Access to the plant is by means of East Martin Street going over the levee off Louisiana State Highway 34. The plant is described as a Hydrograph Controlled Release plant which depends upon the water flow in the Ouachita River for its discharge limits. The discharge parameters include BOD, pH, TSS, FC, copper and total residual chlorine. The plant treats domestic and industr ial sewerage for both the City of West Monroe and West Ouachita Sewerage District #5. The plant consists of parallel 50 acre oxidation ponds for primary treatment with upflow rock filters and disinfection by chlorination and dechlorination used for secondary treatment. The treated water is then discharged into the Ouachita River. Chlorination is accomplished through the use of two one ton cylinders with two on standby. This ensures a continous process for removing the pathogens from the wastewater. The chlorine gas flows from the cylinders via cylinder mounted regulators, going through vacuum lines and finally being injected into the water stream If for any reason vacuum is lost, such as power failure, tubing breakage, ect., the regulators automatically stop the flow of chlorine. This ensures a safe process. Included in the chlorination process is the dechlorination process. This process consists of two one ton cylinders feeding sulfer dioxide into the water stream a t a post chlorination location. The purpose of this process is to remove chlorine from the water before discharge into the receiving stream. This process uses identical procedures and safeguards as does chlorination. These are the only processes involving toxic chemicals and are the only processes covered by the risk management plan. The worse-case scenario contained in this RMP was modeled using EPA'S RMP Comp. It assumes the rupture of either a one ton chlorine or sulfer dioxide cylinder, which are the largest vessels on site. The alternative scenario was also based on EPA'S RMP Comp. It assumes a failure of a pressure regulator on a chlorine or sulfer dioxide cylinder. Neither scenario assumes any active or passive mitigation measures. In the previous five yearsn there has been one release of chlorine. This involved less than one pound of chlorine which had condensed in a regulator. There were no injuries or evacuations, although emergency personnel did respond. The City of West Monroe Wastewater Treatment Plant is included in the written community emergency plan handled by the Ouachita Civil Defense Agency. Plant personnel would not respond to an emergency release. Primary responders would be the Ouachita Parish Fire Department and the City of West Monroe Fire Department. Ongoing safety upgrades are a continuing process at the City of West Monroe Wastewater Treatment Plant. Hazards identified with the last hazard review are in the process of being corrected at this time. |