AWWA ACE59837

Focused on maintaining public water supply excellence, the City of Port St. Lucie performed this projectto increase water distribution operational efficiency, conserve water, and improve water quality at thetap. As one of the fastest growing cities in the United States, the City of Port St. Lucie is rapidlyexpanding its distribution system. Phased development has resulted in low flow velocities and highwater age in new distribution piping. The City currently conducts continuous flushing at severallocations throughout the water distribution system to optimize water distribution quality for the City'scustomers during this challenging growth period. The amount of finished water currently used forflushing is nearly 9% of the City's average annual flow. Minimization of flush water will loweroperational costs and reduce the City's overall water use.An accurate hydraulic model is needed to assess potential benefits to distribution system water qualityand flushing requirements. The City's existing and antiquated hydraulic model was updated, calibratedand used to optimize flow through the distribution system, maintain adequate disinfectant residual, andminimize stagnant water. This paper presents the capabilities of a hydraulic model for the purpose ofoptimizing water quality and minimizing flush water. The hydraulic model's water quality modelingfunctions were used to:identify potential water quality problem areas;maintain adequate disinfectant residual;optimize flows throughout the distribution system; and,reduce flush water volumes.Network analysis software is readily available to perform water quality modeling. For this project, thehydraulic model was run during average annual conditions and the residence time or water agecalculated by the modeling software. Water age was used as a surrogate for flushing recommendations.The water age data was graphically displayed to identify portions of the distribution system with thehighest water age and lowest disinfectant residuals. Once the current system water age was calculated,the optimization was conducted to reduce flushing water quantities and improve overall system waterquality. A 7% annual savings in flushing water was achieved through the optimization process anddistribution system water quality significantly improved. Includes 3 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/17/2004

Number of Pages:

11

File Size:

1 file , 430 KB