Jasper Wastewater Treatment Plant - Executive Summary |
|
Jasper Wastewater Treatment Plant The Jasper WWTP has a practical overall approach to chemical safety in the plant especially as it relates to protection of the employees and surrounding community. The standard operating procedures for handling chlorine at the plant is practical and incorporates safety measures that are protective. The Jasper Wastewater Treatment Plant is the POTW for the City of Jasper, Indiana. The plant uses chlorine to disinfect the treated wastewater effluent before its discharge to the receiving stream. The inventory of chlorine at the plant normally includes one full one-ton cylinder and one partially full one-ton cylinder. The worst-case scenario for this plant assumes that chlorine is completely released from 1 one-ton (2000 lb) cylinder over a period of 10 minutes. Using Exhibit 4-3 the EPA's Risk Management Program Guidance for Wastewater Treatment Plants (40 CFR Part 68), the toxic endpoint for this urban site is 1.3 miles with a F stability class and wind speed of 1.5 meters per second. There would be an offsite impact with this worst-case scenario. Although, chlorine cylinders kept inside secondary control room (enclosed room - passive mitigation process), the cylinders are delivered initiatilly delivered and handled outside prior to being placed on scale. The Chlorine Storage Standard Operating Procedure for the WWTP helps to mitigate the likelihood of the worst-case scenario occurring. The SOP indicates that chlorine cylinders are handled and replaced with a new and full cylinder during the day shift only. Two plant personnel in addition to the delivery person are present when handling any full or empty cylinder. The alternate release scenario for this facility is the most likely event to occure that would result in a release of chlorine to a endpoint (in this case, only residential). At this facility, the most likely event would be a blown pressure-relief valve on the tank. However, this event would be mitigated by the fact that test for leaks are performed when the cylinder is hooked up for the first time and on a daily basis at 8 am by the day shift and chief operator. A visual inspection by operating personnel is done every 2 hours while making their rounds. Gas monitors are also in place which would help to mitigate this scenario. Using Exhibit 4-13 from the above guidance, the release rate and distance to an endpoint for a liquid chlorine release through a 1/4-inch diameter valve opening (closest and most conservative size to actual 3/8-inch diameter valve opening) are 150 lbs/min and for a urban setting 0.2 miles, respectively. This facility is subject to EPCRA 302 with regards to chlorine. In addition, this facility ensures compliance with safety information requirements under NFPA 820 (for wastewater treatment plants), OSHA (29 CFR 1910.119) and local building codes. The following practices are conducted as part of this facility's prevention program: (1) annual classroom training on how to handle chlorine and related releases, (2) internal safety/maintenance inspections (SCBA training, routine maintenance of chlorination systems, etc.), and (3) on-the-job training and constant monitoring by experienced personnel. No accidents have been recorded at this facility within the last five years due to the stability and training of the workforce at the plant. The plant's emergency response plan is adequate and includes general procedures, emergency alarms, evacuation sites, procedures for emergency shutdown of operations, identified hazards and who responds and how, control of workplace hazards, maintenance of emergency equipment with emergency telephone listing (public entities, etc.). There is close coordination of emergency response measures with local emergency response committee. The following changes to improve safety are planned for this facility within this year: 1) Complete documentation of training conducted, who receives the training and when. 2) Routine saf ety meetings with employees that fully documented and kept onsite. 3) Updated process hazard analysis as per 1910.119. 4) Updated and complete emergency response (action) plan for site to incorporate more details with regards to responding to accidential releases of chlorine and/or other regulated substances. 5) Performance of a yearly compliance audit to ensure that the above changes are incorporated into this facility's safety program as well as continued adherence to the level of safety currently maintained by the WWTP. 6) External safety inspection by appropriate local agency. |