What is a CSO?
A discharge of untreated wastewater from a combined sewer system at a point prior to the headworks of a publicly owned treatment works. CSOs generally occur during wet weather (rainfall or snowmelt). During periods of wet weather, these systems become overloaded, may bypass treatment works, and discharge directly to receiving waters.
CSOs contain raw sewage from homes, businesses and industries, as well as stormwater runoff and all the debris and chemicals that wash off the street or are poured in storm drains. They contain untreated human waste, ammonia, pesticides, nutrients, petroleum products, oxygen-demanding substances (which harm fish) and other potential toxins and pathogenic microorganisms associated with human disease and fecal pollution.
The frequency and intensity of CSOs fluctuates with the weather. The more rain that falls in given period of time, the more likely it is that bottlenecks will occur in the collection system and/or treatment plants will reach their capacity limits. Extended light rain will trigger CSOs, as will shorter, heavier storms.
At this time the Town of Fortville has 1 CSO located at the sewer treatment plant.