Modeling Water Quality in Distribution Systems

Water quality although acceptable when it leaves the treatment plant may deteriorate before it reaches the user. Changes in quality may be caused by chemical or biological transformations, by a loss of system integrity, or by blending of waters from different sources. Until recently, little attention has been paid to the problem of changes in water quality in the distribution system. This paper applies a sequential steady‐state approach to modeling water quality in distribution systems and compares the results to field data. The field data showed significant spatial and temporal water quality variation in the distribution system. The sequential steady‐state solutions provided a reasonable representation of changes in water quality with time. A major conclusion of the research is that an understanding of the hydraulic flow patterns and directions that create gradients of concentration is extremely important in interpreting quality modeling results. Field quality data is important in developing, verifying, and understanding predictive models. Such quality data should be at time intervals sufficient to reflect changes in system dynamics.