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Case Study


In order to get a better understanding of the infiltration and inflow into their newly separated sanitary sewers, Grand Rapids engaged Xylem in utilizing BLU-X, a real-time decision support system consisting of smart sensors and actuators that track conveyance capacity.

Grand Rapids, MI is a community that has garnered accolades in the clean water industry for taking significant proactive steps to improve its sewer system. In the early 1990s, “River City” took the initiative to invest in transforming its collection system from a combined sewer system to separate storm and sanitary sewers. By moving from a single pipe for both stormwater and wastewater conveyance to separate pipes, the City avoided the introduction of sewage into its waterways, reducing overflows and subsequent pollution into the landmark Grand River that flows to Lake Michigan 40 miles downstream.


After nearly 25 years, Grand Rapids finished retrofitting its combined sewer overflow system to a separate sanitary and stormwater system, completing its long-term control plan (LTCP) in 2015. But now, the City needed to get a better understanding of the infiltration and inflow into these newly separated sanitary sewers to ensure compliance with a mandate from the Michigan Department of Environmental Quality (DEQ). This mandate allowed them zero overflow events of any kind, except as part of a wet weather event of a magnitude in excess of a 24-hour, 25-year storm.

For compliance purposes, the City needed analytic data to certify performance and understand how the system behaved during a wide variety of wet and dry weather conditions. While gathering this information, the City was also presented with a hydraulic report stating that areas of the community were experiencing excessive surcharging and flooding. They suspected otherwise, but needed proof to answer regulators, as mitigation to eliminate the surcharging and flooding was estimated to cost much as $1 billion; a capital expense the city could ill afford.

What solutions did Xylem and Grand Rapids come up with to solve this challenge? Find out and explore the results we achieved together by downloading the full case study below.

Project Highlights

Data demonstrated that the infiltration and inflow problem could be solved for $30-50 million as opposed to the original $1 billion estimate

Real-time decision support system brought in to help the Environmental Services Department for the sanitary system separation

City has expanded the sensor network to more parts of the system

Services Provided

• BLU-X real-time decision support system (RT-DSS) deployed to help characterize infiltration and inflow performance on sanitary lines
• All sensor data presented on one unified platform
• Integration into Grand Rapids’s existing IT networks