Nearly all water supply systems in Egypt include storage tanks (elevated and ground). They are the most important components of a water distribution system but are generally the least understood in terms of their effect on water quality. Long detention periods in storage tanks can have negative impacts on water quality in drinking water networks, including the increase of water age, reduced disinfectant residuals, and increased growth of disinfectant by-products and bacterial levels. This paper applies WaterCAD model to simulate water quality in the elevated tank at Benha water distribution system and compares the results to field data. The applied software implements the Eulerian Discrete Volume-Element Method (DVEM) to solve the numerical constituent transport problem for the system being analyzed. The model is formulated analytically from mass balance principles, where specific hydrodynamic processes are modeled. The model can be used effectively for investigating the effect of storage in the elevated tanks on water quality. Results indicated that water quality is degraded as result of long residence times in storage tanks. It is clear that much more research is needed in order to understand truly the effect of location, geometric configuration and the location of inlet-outlet pipes of the elevated tanks. |
