Case Study

In order to maximize their existing capital assets, reducing overflows and optimizing overall operation efficiency, the Metropolitan Sewer District of Greater Cincinnati (MSD) engaged Xylem in utilizing BLU-X, a drainage network optimization solution that uses a real-time decision support system consisting of smart sensors and actuators that track conveyance capacity.

Cincinnati’s sewers discharge an average of 11.5 billion gallons of combined sewage every year into the Ohio River and its tributary streams within Cincinnati’s urban watershed.

In 2002, the EPA entered into a federal consent decree with MSD, mandating the elimination of sanitary sewer overflows and significant mitigation of combined sewer overflows into receiving waterways. Engineers estimated the cost to mitigate the sewer overflows at $3.1 billion, an unacceptable capital expense to pass along to MSD’s customers.


Recognizing the generally inadequate stormwater management capabilities of their existing combined sewer system, MSD prepared a comprehensive wet weather improvement plan. MSD recognized that full sewer separation and deep tunnel construction are massive capital investments that have a very low return on investment because they create only episodic benefits during peak flow events and are single-use assets with little additional community wealth creation.

Instead, MSD’s objective was to maximize existing capital assets — such as sewer interceptors, storage and treatment facilities, and pump-stations — to reduce overflows and gain system-wide benefits through advanced control logic that will optimally operate MSD’s urban watershed.

What solutions did Xylem and MSD 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

Overflow volumes reduced by 247 million gallons annually

More than a 90% reduction in cost compared to initial capital work estimated at $38 million

CSO mitigation achieved at a price of less than$0.01/gallon

Services Provided

• BLU-X real-time decision support system (RT-DSS) to manage storage and conveyance
• RT-DSS integrated into MSD’s existing SCADA and IT networks
• All sensor data presented on one unified platform