Since the early 1990's, the City of Wilmington has been implementing a series of long term control plan (LTCP) improvement projects in order to reduce CSO events and to increase the annual average flow captured for treatment.
One of the key components of the City’s LTCP consists of implementing a coordinated system-wide real time control (RTC) solution to better manage flows in the collection system in order to maximize available storage, conveyance and treatment capacities.
The RTC project in Wilmington encompasses the design, retrofitting, and implementation of four control stations, the control of the three existing siphons, and the design and implementation of a central station and a new SCADA system of data collection and measuring sites for monitoring and control purposes. All of the local stations are linked to the central station via a telemetry system. The Csoft™ software optimizer manages the system automatically from the central station, under the supervision of operators.
More specifically, Tetra Tech CSO carried out the following activities:
Average % of CSO Reduction: 76%
Capital Investment Savings: $87M
"We'd have to tear up several parks in the city to build more tanks. I'm not a scientist, but we knew there had to be ways to divert the way water flows in pipes. We are among the selected communities that have utilized Real Time Control that makes optimum use of our sewer capacity to manage and minimize overflows. This plan is cheaper, quicker and actually increases the amount of overflow we're trying to catch. The Enhanced LTCP would increase the CSO capture and treatment rate to 87% or higher, reduce CSO control costs by more than $87 million, and accelerate implementation by ten years.”
– Mayor James M. Baker, City of Wilmington, Delaware