What's up with all the sewer infrastructure work throughout St. Louis? Read about the EPA v. MSD Consent Decree below:

The St. Louis metro area is in the process of undergoing major upgrades to its sewer system. Like many systems across the country that were constructed before separate storm and sewage transport, during heavy rain and storm events in St. Louis, (see Sewer Systems and Wastewater for information on combined sewer systems), stormwater and wastewater from the sewage system discharge untreated into the local waterways from combined segments of the sewer system. According to EPA, untreated sewage discharges account for thousands of cases of gastrointestinal illnesses each year in the U.S. In order to address the sewer overflow conditions as well as to improve the sewer system infrastructure in our community, a Consent Decree between the Environmental Protection Agency, the Missouri Coalition for the Environment, and the Metropolitan St. Louis Sewer District in The United States et al v. The Metropolitan St. Louis Sewer District, No. 4:07-CV-1120 (E.D. Mo.) was entered with an Effective Date of April 27, 2012 (EPA, St. Louis' Clean Water Act Settlement).

Under the Concent Decree, MSD is committed to infrastructure improvement projects for work in both the Sanitary and Combined collection systems (as introduced in the Sewer System and Wastewater page) and in the wastewater treatment plants (WWTPs) with a total estimated cost of $4.7 billion over the next 23 year period. 200 or more SSOs will be eliminated, CSO control measures implemented, and the capacity of the District's WWTPs will be expanded to reduce pollutant discharges throughout the system. The objective of the improvement projects will be to eliminate and mitigate overflows of untreated raw sewage prioritizing known problematic areas and to reduce contaminants entering the system from stormwater with green infrastructure projects (MSD's Project Clear). MSD is required to take the following actions:
  • Remedial measures and schedules for Sanitary Sewer System include:
    • Sanitary Sewer System Characterization Report: Identification and mapping of all constructed SSO outfalls, signage establishments of all streams, creeks, drainage ditches, and swales receiving Constructed SSO discharges, monthly inspections of Constructed SSO locations and all downstream signs.
    • Elimination of constructed SSOs throughout the system over the duration of the Consent Decree with the majority eliminated in the first 12 years:
      • Since the Consent Decree was finalized, MSD has completed early elimination projects according to schedule for constructed SSOs through December 31, 2012 identified in the map below. MSD has also employed $30 million in applicable and accepted engineering methods for reducing inflow and infiltration through December 31, 2013 for other system improvements.

Explore the interactive map below to see where and when SSO elimination projects may be scheduled to occur near you. Select 'Layers' to show/hide information of interest.

Additional requirements for Consent Decree compliance include:

  • Sanitary System:
    •   Sewer System Evaluation Survey: Elements include data management, quality control, data review, rainfall gauges, flow monitoring equipment, rainfall and flow monitoring, and also investigative activities; results shall be used to develop Sanitary Sewer Overflow Control Master Plan as well as develop remedial measures in the plan.
    • Hydraulic Model: MSD shall use the model to assess the hydraulic capacity of the SSOs and shall use its best effort to produce the most adequate and accurate results.
    • Capacity Assurance Evaluation: Identification of peak flow capacities within the Sanitary Sewer System.
    • Sanitary Sewer Overflow Control Master Plan: No later than December 31, 2013, MSD shall submit the Plan to EPA, with a copy to MCE. The Plan shall address remedial measures, a flow metering plan, a schedule of specific projects for the Elimination of Constructed SSO Outfalls, and estimated capital and costs for each identified project.
    • Capacity, Management, Operations, and Maintenance Program Plan: MSD shall submit to the State, the EPA, with a copy to MCE for review no later than six months from the Effective Date by MSD. The Plan shall includes procedures for inspecting and cleaning Gravity Sewer Lines, procedures for inspection, repair, rehabilitation, and replacement of Sewer System manholes, procedures for ensuring that permanent repair, rehabilitation, and/or replacement of sewer pipes are properly designed and constructed to prevent overflows and reduce sources of infiltration and inflow.
    • Fats, Oil and Grease Control (FOG) Program Plan: No later than three months from the Effective Date, MSD shall submit to EPA and the state for review and for EPA’s approval, with a copy to MCE. Performance and maintenance guidelines for FOG shall be included.
    • Private Infiltration and Inflow Reduction Program: No later than six months from the Effective Date, MSD shall submit to EPA and the state, with a copy to MCE, a plan describing proposed remedial actions regarding reduction of storm water discharge, surface waters, ground waters, roof runoff, excessive I/I to the Sanitary Sewer System.
    • Certification of Legal Authority
    • Revised Non-Capacity Related SSO Response Plan: No later than three months from the Effective Date, MSD shall provide to EPA and the State for review and for EPA’s approval, with a copy to MCE a revised plan responding non-capacity related SSOs and minimizing the environmental impact and potential human health risk from contact with sewage.
    • Building Backup Response Plan: No later than three months from the Effective Date, MSD shall submit the plan to address Building Backup recurrence.
    • Cityshed Mitigation Program: MSD shall continue its Cityshed Mitigation Program to mitigate the effect of wet weather surcharging and overland flooding of the combined sewer system (Citysheds).
  • Implementation of Combined Sewer Overflow Control Measures and Post-Construction Monitoring
    • Implementation of CSO Control Measures
    • Post-Construction Monitoring Program
    • Achievement of Performance Criteria
    • Compliance with MSD’s Missouri State Operating Permits
    • Supplemental Remedial Measures Plan

 Read the full Consent Decree.

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