How Municipal Water Authorities Are Using Simulation Tools to Improve Performance and Reduce Costs
With the unrelenting population growth in large and mid-size North American cities, water resources have become a critical concern. The old paradigm that considered water an unlimited resource has led to inefficient usage. In the past fifteen years, the average unit price of raw water in the United States has increased at more than 1.5 times the rate of inflation. Capacity for wastewater has also become an increasing challenge, leading to more stringent regulations. As one example, in the US, the discharges from Combined Sewer Overflow (CSO) chambers are a major water pollution concern for approximately 900 communities containing around 40 million people. The US Environmental Protection Agency's (EPA) CSO control policy, published in 1994, is a national framework for the control of discharges through the National Pollution Discharge Elimination System (NPDES) permit program. Key milestones of the CSO policy include the implementation of “nine minimum controls” and the development of long term CSO control plans. Elements of these plans include characterization, monitoring, and modeling activities, along with the evaluation of alternatives.