AWWA JAW63488

An established method for directly determining the kinetics of chlorine decay attributable to pipe-wall reactions does not currently exist. Wide variability in wall reaction parameters, attributable to varying characteristics of a pipe such as age, material, and diameter, also make the task of estimating these parameters tedious at best. An inverse model that accurately estimates water quality reaction parameters is developed. The parameter estimation problem is formulated as an unconstrained optimization problem, for which an inverse modeling approach using a water quality simulation model and a stochastic search genetic algorithm (GA) as routines in the computational procedure is adopted. Calibrating a water distribution model using GA, which attempts to find the best solution by mimicking the natural selection process in genetics, can automate and simplify the process for any applicable reaction kinetics. In addition, a GA-based water quality calibrator is applicable to many unknown individual, global, or grouped reaction parameters. Applying the inverse model to two real-life networks demonstrated the model's ability to compute the various types of unknown reaction parameters. GA was found to be the most appropriate method to use with a large number of parameters. Includes 22 references, tables, figures.