AWWA WQTC65838

This study addresses the occurrence of discolored water at the customers tap due to particulate matter. Slaats et al. (2003) describes the problem and explains a method to investigate the fouling behavior of pipes in drinking water distribution systems. This study describes a new approach to modeling the behavior of particles in water at a small scale pilot plant designed as a pipe loop. Study conclusions found that the common practice of using only one parameter to describe the mobilization of particles dependent on hydraulic conditions is insufficient. It is more accurate to assume the partial mobilization of sediment and attachments. Not all sediment is mobilized when a critical water shear stress is exceeded. The settling velocity of a particle in the pipe flow varies and depends on the height of the pipe cross section due to the changing influence of most forces. It is important to consider cohesion and adhesion due to the small particle sizes, thus influencing the settling and transport by the fact that most of the sediment does not settle but forms wall attachments. Includes 8 references, figures.