Equalizing wet weatherflows

Sanitary sewer overflows and combined sewer overflows can wreak havoc. They can flood basements, contaminate drinking water sources and recreational water bodies, and flow of manhole covers onto streets and playgrounds. Because overflows contain untreated wastewater, parasitic organisms are unleashed. Exposure to these contaminants through direct skin contact, inhalation or ingestion (either during recreation or through tainted raw seafood) can cause illness ranging from mild gastroenteritis to life-threatening cholera and dysentery. Pressured by the US Environmental Protection Agency to control these overflows, many municipalities are turning to flow equalization basins (FEB). FEBs increase a system's capacity dramatically by retaining excessive flows until the collection system is better able to handle them. Best of all, FEBs cost considerably less than more traditional methods. Proper planning regarding an FEB's location, construction, and operation and maintenance can go a long way toward eliminating sewer overflows and the public health threats that accompany them.