"Smart" Sewage and Runoff System

The new system being installed in South Bend, Indiana will use a citywide network of 105 manhole-mounted sensors and "smart valves" to automatically hold back the flow of rainwater and sewage in existing sewer system pipes and retention basins until the storm has passed. With floods rampaging through the Midwest, as we speak, it looks as if South Bend could use the system right now.

Engineers from Purdue and Notre Dame universities are working with Indiana startup EmNet LLC on a wireless sensor network for the city of South Bend to prevent raw sewage from overflowing into waterways, especially from surging runoff during storms.

The system, called CSOnet, will consist of numerous computer chips that communicate with each other over a wireless radio network. These microcomputers are embedded in the city sewer system and are connected to flow sensors, pressure sensors and valves in a network that works in a cooperative manner to control storm runoff, Montestruque said.

Sensors are mounted on the undersides of manhole covers and will have to perform in an urban setting full of interference sources, said William Chappell, a Purdue assistant professor of electrical and computer engineering who helped design the sensor technology.

“The sensors must be made to operate in harsh conditions and adapt dynamically to changes in the wireless system, such as interference or the presence of parked or moving cars,” Chappell said. “And the system will need to broadcast sensing data generated underground to a network that operates above ground in a challenging environment.”

Research to develop the system began in 2004 under the direction of Jeffrey W. Talley, an associate professor of civil and environmental engineering at Notre Dame. The technology is an example of a “cyberphysical system,” or a network of computers tightly integrated with sensors and motorized controls, said Michael Lemmon, a Notre Dame professor of electrical engineering.

Such systems are currently being proposed for use in various applications, including control of the national power grid, automated manufacturing, air traffic control, homeland security and material distribution for industrial supply chains.

Saurabh Bagchi, a Purdue assistant professor of electrical and computer engineering, has developed critical software, called middleware, for the system. The software allows the sensors to talk to each other in an “ad-hoc mesh network.” This means there is no need for preexisting infrastructure,

Then valves will divert the flow into temporary storage sites. The sewage will be selectively released later so that it flows into the treatment plant when capacity is available, preventing the waste from being dumped into Indiana waterways, including the St. Joseph and Wabash rivers.

Raw sewage is very toxic. It’s going to take an estimated $50.6 billion to solve the problem in the United States alone. The amount of sewage dumped into rivers, lakes and the oceans by combined sewer overflows is equivalent to the water carried into the Gulf of Mexico by the Mississippi River in one week. That’s 850 billion gallons per year.

Cities are fined for failing to meet U.S. Environmental Protection Agency standards. It is estimated that $4 billion will be needed to bring Indiana within federal guidelines over the next few years.

Talley, an environmental engineer, also is developing a technique of using ultrasound to clean water diverted to temporary holding facilities. The method works by bombarding water with high-frequency sound waves, producing bubbles that implode, generating high heat that purifies water.