Fox Metro Water Reclamation District - Executive Summary
The Fox Metro Water Reclamation District (FMWRD) is dedicated to the transport and treatment of waste water in a manner that is protective of the community. Protecting the health and safety of FMWRD employees as well as the general public during waste water treatment activities is a major concern. FMWRD pride's itself in it's excellent operating record. The facility was first constructed in 1929 and in the last 20 years, no employee has had a reportable injury and no accidents have occured which would put the public at risk. |
The FMWRD developed a safety committee which is responsible for the administration and enforcement of the safety rules and procedures The committee is made up of management and labor representatives, which acts as a resource for FMWRD management, department heads, supervisors, and employees. The safety committee is responsible for accident and
injury records, development and implementation of the safety and education program, safety inspections and safety standard compliance.
FMWRD treats approximately 35 million gallons of wastewater on a daily basis. The general process for treating waste water utilizes physical, chemical, and biological processes to remove pollutants. First, bar screens and grit chambers remove large particles while primary settling basins permit smaller particulates to settle out from the influent flow stream. The flow is subsequently mixed with activated sludge (bacteria) which remove organic pollutants through bacterial metabolism. The bacteria are then allowed to deposit into secondary settling tanks. Finally the flow is passed through sand filters, disinfected, and discharged to the Fox River.
This Risk Management Plan (RMP) was created to address methane, a flammable gas, which is created through anaerobic digestion. Anae
robic digesters are large tanks of bacteria that are utilized to decompose organic solids from wastewater. These organic solids are called sludge. The process of anaerobic digestion of wastewater sludge eliminates pathogenic organisms, reduces the amount of materials that require ultimate disposal, creates a sludge which can easily be dried and recycled back to farmland enhancement, and creates gases that can be used as a fuel supply.
The gas created from this process contains 63.2% methane, 35.3% carbon dioxide, 1.1% nitrogen and 0.6% water. This gas is collected from the digesters and stored in a sphere for storage and later use, and the excess gas is burned off by on-site flares. The digesters and piping contain approximately 5,405 lbs of methane gas, while the capacity of the sphere is approximately 6,945 lbs. of digester gas. Therefore the total digestion process generates an approximate amount of 12,350 lbs. of methane gas.
RMP* Comp, a software modeling program created b
y the Chemical Emergency Prevention and Preparedness Office of the Environmental Protection Agency, the National Oceanic and Atmospheric Administration, and the Cameo team of the Hazardous Materials Response and Assessment Division was utilized to determine the worst-case release scenario should a release occur from the largest gas containing vessel, the gas sphere. The modeling program was utilized to develop a theoretical vapor cloud explosion radius upon immediate release of all 6,945 lbs. of potential gas in the sphere. Failure of the gas sphere containing 6,945lbs. of digester gas could potentially produce a vapor cloud explosion scenario within a 0.20 mile radius.
Total failure of the methane gas sphere is an unlikely scenario because a pressure release valve located in the top of the sphere is designed to ensure that the tank does not become over pressurized and explode. A more likely scenario would consist of a ruptured disk or relief valve failure at one of the digesters
. If this were to occur, a chain reaction could potentially occur involving all five (5) of the digestors. A total of 5,405 lbs of methane gas could cause a vapor cloud explosion scenario within a 0.10 mile radius.
Release Prevention Program
The Release Prevention Program consists mainly of employee health and safety training, preventative maintenance and strict operating procedures. Employees are trained immediately upon employment and annually thereafter on proper welding and cutting procedures, lock out/tag out procedures, proper lifting, hand safety, fork lift operation, hazard communication, fire extinguisher training, and first aid/CPR. Preventative maintenance prevents breakdowns, reduces wear, improves efficiency and extends the life of equipment and structures while enhancing the reliability and dependability of the wastewater treatment equipment. Strict operating procedures ensure that the proper start-up/shut-down sequences are utilized when operating equipment.
e Year Accident History
FMWRD has had no accidental releases of methane in the past five years. No one on-site or off-site has been injured, and no emergency evacuations have resulted.
Emergency Response Program
An Emergency Response Program is in place at FMWRD in the case that an emergency were to occur. The employee/employees first aware of the emergency would notify the emergency response center who in turn would immediately notify emergency responders (Oswego Fire Department, Kendall County Sheriff's Department). Each employee at the facility has been assigned duties in the event of an emergency and is trained to fulfill those duties and assist professional emergency responders.