Econchate Water Pollution Control Plant (WPCP) - Executive Summary

| Accident History | Chemicals | Emergency Response | Registration | Source | Executive Summary |

Policy Statement 
It is the policy of the Econchate Water Pollution Control Plant (WPCP) and the Montgomery Water Works and Sanitary Sewer Board (MWWSSB) to safely operate the WPCP, reducing to the greatest extent possible any hazards associated with the processes and reducing any subsequent risk to the surrounding community, personnel, and environment.  The policy includes working with the surrounding community and local emergency response agencies to promote a spirit of cooperation and teamwork, to orchestrate an effective contingency plan in the unlikely event that a process incident occurs at Econchate WPCP. 
 
Stationary Sources and Regulated Substances Handled 
Primary Activities:  Municipal wastewater treatment is the primary activity. 
Use of Regulated Substances:  Chlorine is used primarily as a disinfectant.  Other possible uses of chlorine are for odor control and to assist in settling of biosolids in the clarification process. 
 
Digester gas is a byproduct of anaerobic digestion, 
which is a process used to reduce the volume of excess biosolids produced during wastewater treatment.  The digester gas is flammable because it contains 65 percent by volume of methane, a flammable gas.  The quantity of digester gas stored is 8,710 pounds, which is below the threshold quantity for regulation under the RMP rule.  Therefore, it is not included in the data elements. 
 
Quantities of Chlorine Handled and Stored 
Amount Handled:  Two 1-ton containers, equivalent to 4,600 pounds;  
Amount Stored:  Twelve 1-ton containers, equivalent to 27,600 pounds 
 
Chlorine Worst-case Release Scenario 
Failure of two liquid chlorine cylinders resulting in a release of 4,600 pounds of chlorine in 10 minutes.  There are no administrative controls in place.  The 12 containers are stored on an elevated platform with no side walls.  Therefore, passive mitigation is not considered. The release rate of 3.48 kg/s is modeled using DEGADIS 2.1. 
Distance to Endpoint:  Under the worst-case weather condit 
ions prescribed by the RMP rule, the distance to a toxic endpoint of 3 ppm is 2.55 miles, beyond which there will be enough dispersion to no longer pose a hazard to the public. 
 
Chlorine Alternative Release Scenario 
Release of chlorine from a pipe <-inch in diameter connecting the chlorine container to the evaporator.  For a release duration of 15 minutes, the release rate is 0.05 kg/s, which is modeled using DEGADIS 2.1.  No active mitigation system such as a chlorine scrubber is installed. 
Distance to Endpoint:  Under realistic weather conditions of 3.0 m/s wind speed and a wind stability class of "D," chlorine could travel 0.39 miles or 0.62 km before dispersing enough to no longer pose a hazard to the public. 
 
Accidental Release Prevention Program and Chemical-specific Prevention Steps 
Econchate WPCP is in compliance with the RMP Rule, 40 CFR 68.  The facility has conducted a comprehensive review of all systems, as well as administrative, technical, operating and maintenance proced 
ures, in addition to the other required program elements of the RMP rule.  A hazard review was conducted at this facility using a checklist extracted from the Guidelines for Hazard Evaluation Procedures . 
 
Five-year Accident History 
During the past 5 years, Econchate WPCP had one accidental release of chlorine gas in June 1995.  The release was less than 10 pounds.  One person onsite was injured and hospitalized for 4 days.  No one offsite was injured, and no evacuation was necessary. 
 
Emergency Response Program 
The MWWSSB has an Emergency Response Program, which applies to the Econchate WPCP, that coordinates response efforts with the local fire department's HAZMAT team, the police department, and the hospital.  Response activities also have been discussed with the Alabama Emergency Management Office Agency. 
 
Planned Changes to Improve Safety 
The changes to improve process safety identified during the hazard review and those identified in the report, Vulnerability Analysis of the Wate 
r and Wastewater Systems , are given below: 
1.  Enclose the chlorine storage area and the chlorination room. 
2.  Install sprinkler systems in the chlorination room and chlorine storage room. 
3.  Install a chlorine scrubber and associated ventilation system and instrumentation. 
4.  Increase security by modifying the main entrance gate to prevent unauthorized personnel from accessing the site without the proper security code. 
5.  Ensure that adequate fire extinguishers are located at appropriate points throughout the facility. 
6.  Acquire two more positive system, self-contained breathing apparati for personnel safety in case of a chlorine leak, and provide adequate training to Econchate WPCP personnel on their proper use.
Click to return to beginning