Clear Lake City Water Authority WWTP - Executive Summary
The Clear Lake City Wastewater Treatment Plant is currently a 9.0 MGD plant scheduled to undergo a 1.0 MGD expansion in the next two years. This facility is committed to accident prevention and protection of employees and the public. The facility is an activated sludge wastewater treatment plant operating in the contact stabilization mode. It utilizes chlorine gas to disinfect a portion of the treated effluent and ultra-violet waves to disinfect the remaining flow. The plant was constructed in four 2.25 MGD phases starting in 1976 and has never had a reportable release of a toxic chemical. |
The worst case and alternate scenarios utilize the EPA Risk Management Program Guidance for Wastewater Treatment Plants to model the distance to the toxic end point. The worst case scenario for chlorine is an urban setting, 1.3 miles to the toxic end point and effecting 7255 people. The alternate scenario for chlorine is 0.2 miles to the toxic endpoint effecting 167 people.
The process safety
hazard analysis was conducted using the what-if methodology. Sixteen possible release scenarios were analysed using this method. The consequences of the scenarios and ways to prevent or minimize the release of toxic gases are presented. The safety management plan also contains operating procedures for the chlorine system. These procedures deal with handling and storage, controlling leaks, loading and unloading cylinders, procedures for changing cylinders, use of SCBA's, and first aid and health considerations. These procedures also include the Standard Operating Procedures (SOP's) for the operator to handle detection, alarms and leak notification.
To maintain compliance with the program, the plant operator will certify that training has been provided to personnel operating the chlorine system. Also, refresher training will be conducted yearly. This training will cover the areas of process safety information, operating procedures and emergency procedures. Training records will
The mechanical integrity section itemizes the preventive maintenance required on chlorine related equipment. This section also covers training of maintenance personnel. Inspection and testing procedures for the chlorine equipment is presented in this section along with the maintenance training documentation.
The emergency response plan addresses the requirements of 40 CFR 68 pertaining to notification, medical treatment, response procedures, planning, use and maintenance of emergency equipment, employee safety and emergency response evaluation dealing with chlorine gas. After discovery of a leak, the wastewater superintendent(or the plant operator in charge) and one other person will make an assessment of the situation. If the assessment indicates that repair is possible, appropriately trained staff members will attempt to repair the leak. If the assessment indicates that a major leak has occurred, the local emergency response agency (the Pasadena Fire Department
) will be notified with a recommendation from the plant operator. The emergency response plan has been reviewed by Pasadena Fire Department, wastewater superintendent and the Clear Lake City Water Authority.