The Metropolitan St. Louis Sewer District (MSD) signed a consent decree on Aug. 5 with regulators and environmentalists to make extensive improvements to its sewer systems and treatment plants, at an estimated cost of $4.7 billion over 23 years.
The settlement reached between the U.S. Environmental Protection Agency, the Missouri Coalition for the Environment Foundation and MSD, requires MSD to install a variety of pollution controls, including the construction of three large storage tunnels ranging from approximately two miles to nine miles in length, and to expand capacity at two treatment plants. These controls and similar controls that MSD has already implemented will result in the reduction of almost 13 billion gallons per year of overflows into nearby streams and rivers.
MSD will also be required to develop and implement a comprehensive plan to eliminate more than 200 illegal discharge points within its sanitary sewer system. Finally, MSD will engage in comprehensive and proactive cleaning, maintenance and emergency response programs to improve sewer system performance and to eliminate overflows from its sewer systems, including basement backups, releases into buildings and onto property.
The consent decree also stipulates that MSD spend $230 million in a mitigation program to alleviate flooding to reduce stresses on the system during rain events and sewage flow into the Mississippi River. Further, it will invest in at least $100 million in a large-scale green infrastructure program, and another $30 million on a sewer pipelining program, both of which are focused exclusively in environmental justice areas.
In addition to improving its sewer system and treatment plants, MSD will spend $1.6 million on a supplemental environmental project to implement a voluntary sewer connection and septic tank closure program for low-income eligible residential property owners who elect to close their septic tanks and connect to the public sewer. MSD will also pay a civil penalty of $1.2 million to the United States.
MSD’s sewer system collects and treats domestic, commercial and industrial wastewater from a population of approximately 1.4 million in the city of St. Louis and nearly all of St. Louis County. The system covers more than 525 square miles, and includes seven wastewater treatment plants, 294 pumping stations and more than 9,630 miles of sewer lines, making it the fourth largest sewer system in the United States.
The settlement resolves the claims brought by the federal government in a lawsuit filed in June 2007, alleging that on at least 7,000 occasions between 2001 and 2005, failures in MSD’s sewer system resulted in overflows of raw sewage into residential homes, yards, public parks, streets and playground areas.
Overflows pose a significant threat to public health and water quality because raw sewage can have high concentrations of bacteria from fecal contamination, as well as disease-causing pathogens and viruses. These overflows can occur in basements, backyards, city streets, and directly into stream and rivers. This settlement goes a long way in preventing these overflows.