Fighting Sewage Problems With Sensors

Student: Joshua Herrig (Uni: JLH2208)

Sustainability Problem: Waste, or Combined Sewer Overflow. In many cities the sewers that are used for sewage are also used for rainwater overflow (thus “combined sewer”), so when it rains the sewage, rather than backing up into people’s homes and business plumbing, overflows into rivers, oceans and lakes.

SUMMARY: In America, combined sewers dump 850 billion gallons of raw sewage into waterways. In South Bend, Indiana, in 2008— the worst year for storm and wastewater overflow— 2 billion gallons of untreated sewage flowed into St. Joseph River.

Article: One city’s fight to solve its sewage problem with sensors, by Andrew Zaleski.

  • In 2011, the Environmental Protection Agency forced South Bend into a consent decree, demanding $863 million worth of sewer upgrades. However, South Bend’s citizens would have had to pay $10,000 each to pay for the upgrades, nearly impossible in a town with the average income of $40,000.
  • A company called EmNet, formed by engineer Michael Lemmon and fellow engineers and researchers from Notre Dame University, have deployed a system of sensors in South Bend’s sewer system.
  • After the sensors were installed, South Bend and EmNet implemented a real-time control system, with valves that automatically open and close in response to the sensor data.
  • Since the sensors and control system have been installed overflow has dropped from 42.8 million gallons to 6.9 million in 2020, with the intention of getting overflow to zero.

STAKEHOLDERS: EmNet (private company), South Bend Sewer Department (government), EPA (Federal government), South Bend citizens, humans downstream of the sewage overflow, the environment downstream of the overflow

TECH DEPLOYMENT: This technology has been deployed and seemed to have taken these steps 1. Install the sensors throughout the system 2. Measure where there is overflow and how much. 3. Deploy the valves and real-time control system 4. Implement the valves to respond to overflow and 5. Re-measure how the system is working and fix accordingly.

EDIT: I just realized the MIT story is behind a paywall. Here is a PDF of the story:

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