City of Fergus Falls Wastewater Treatment Plant - Executive Summary
The City of Fergus Falls is committed to the implementation of safe procedures regarding chlorine and sulfur dioxide stored at their Wastewater Treatment Plant (WWTP). The facility has an extensive Risk Mangagement Program that follows OSHA and EPA guidelines. The program emphasizes employee training, emergency response, and equipment inspection/ maintenance. |
The WWTP stores and utilizes chlorine and sulfur dioxide, both of which are regulated substances under this rule. These substances are stored in one-ton cylinders. The maximum quantity on-site at any given time is 8000 lb. per substance. Chlorine and sulfur dioxide are used for the disinfection of treated wastewater prior to discharge.
RMPcomp software was used to conduct the worst-case release scenario for chlorine. Additionally, enclosures (e.g. buildings) were considered as passive mitigation measures in the analysis, which reduced the impact of a potential release. The analysis calculated an impact radius of 0.9 mile
s. This impact radius would result in an offsite impact (members of the pubic could be exposed to toxic concentrations).
For the alternative scenario, the same procedures and mitigation measures were used as listed above for the worst- case release scenario. The scenario chosen for analysis was a hole in the liquid space of one of the storage cylinders. The analysis showed an impact radius of 0.6 miles. This impact radius would result in an off-site impact.
The WWTP's Risk Management Program covers all aspects of safely handling/storing chlorine and sulfur dioxide. This program requires employees to routinely inspect and maintain all process equipment. The program requires that employees receive training on all aspects of process equipment to ensure a safe operating environment, and more importantly, to minimize the possibility of a release.
The WWTP has had no accidental releases of chlorine or sulfur dioxide within the past five years.
This facility does n
ot have its own emergency response program. Response to releases and public notification will be handled by the local fire and police departments.
The facility is in the process of reactivating a dialer system that will be capable of notifying personnel of a release during non-working hours. This will ensure that a release can be identified 24 hours per day.