AWWA WQTC69234

This powerpoint presentation begins by presenting study objectives that include the following: develop a dynamic model to predict distribution system chlorine residual; optimize distribution system chlorine residual; minimize distribution system TTHM level; and, save chemical costs. A brief overview of the Las Vegas Valley Water District (LVVWD) supply and distribution system, and distributed rechlorination system is presented, along with system challenges that include the following: complex distributed chlorination; various convection, dispersion and blending in the distribution system network; and, complicated chlorine reaction with different materials, chemicals and deposits. Approach methodology included the following: utilize supervisory control and data acquisition (SCADA) information and Laboratory Information Management System (LIMS) data; simplify chlorine model by grouping reaction constants; calibrate chlorine model using field tests coupled with a Genetic Algorithm (GA) optimization; and, continue model calibration accounting operation changes or system expansion. Potential benefits include: improved understanding of water quality variations in a complex water distribution system; ensured adequate residual chlorine throughout the system; saved chemical costs by optimizing chlorine dose; and, minimized TTHM growth by tracking and reducing bulk chlorine demand through daily operations. Includes figures.