The Sewer Authority of the City of Scranton - Executive Summary |
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The effluent from the Sewer Authority of the City of Scranton Wastewater Treatment Plant is disinfected using chlorine. Beginning with the next shipment of chlorine, the Scranton Sewer Authority (SSA) will limit the amount of chlorine on-site to a maximum of 12,000 lbs. This will allow for 2 one-ton cylinders to be in-service, 2 one-ton cylinders on stand-by and 2 one-ton cylinders in reserve. To ensure compliance with the RMP Rule, an accidental release prevention program has been established. This will include: training for operators and maintenance personnel, effective standard operating procedures, preventative maintenance, a hazard review, and a review of the necessity for new storage and safety equipment. Training in the use of the on-site self-contained breathing apparatus will continue to ensure all operational personnel are practiced in its use. In conjunction with various operations and maintenance personnel a standard operating procedure was established and will be ela borated on in the O&M manual. A preventative maintenance program has begun with a rebuilding of the chlorine gas manifold system and inspection of all related equipment. A Hazard Review Checklist was completed by appropriate plant personnel and has led to changes in the chlorine handling procedures. A review of new handling and safety equipment is still being conducted and will be discussed later in this summary. The chemical-specific prevention steps include: 10 minute air bottles to be used when changing chlorine cylinders, awareness of toxic and hazardous properties of chlorine, the use of vacuum operating equipment, and the presence of chlorine detection monitors. The Scranton Sewer Authority has the required Emergency Response Plan coordinated with the Lackawanna County LEPC. This plan gives details on emergency contacts, potentially affected areas, and other information regarding the wastewater treatment plant. The offsite consequence analysis includes both the "worst-ca se release scenario" and the "alternative release scenario". The worst-case release scenario for an accidental release of chlorine is the catostrophic failure of a one-ton cylinder. The toxic endpoint selected by EPA is 3 parts per million based on the Emergency Response Planning Guidelines. When the atmospheric dispersion model supplied by the EPA in the RMP Guidance for WWTP Reference Tables and Equations, a distance to toxic endpoint was 1.3 miles and the residential population potentially affected was 9,400. The alternate-case release scenario is a major leak more likely to occur than the worst-case scenario. Pipe failure was identified as most likely scenario. When the atmospheric dispersion model was used for the alternate-case scenario, a distance to toxic endpoint of 0.2 miles and a residential population potentially affected of zero was obtained. The building that houses the chlorine cylinders was considered as a passive mitigation system. Other mitigation measures in use are: chlorine monitors and vacuum piping. Ther have been no accidental releases of chlorine in the past five years. Improvements and procedural changes brought about by investigation and preparation for the RMP are as follows: documentation of standard operating procedures for chlorine cylinder replacement, development of a Emergency Action Plan, initiating a preventative maintenance plan, reduction of chlorine inventory, increased training, commitment to purchase and install automatic emegency shut-offs, plans to increase size and mitigation systems for chlorine cylinders, and investigation into active mitigation systems. |