چكيده لاتين :
It is essential to use new technologies in water treatment plants to reach high quality potable water. The three-layer filter is one such new technology. In this paper, we will present the results of a laboratory investigation on the pilot scale to evaluate the performance of mineral garnet in multi-layer filters and to compare it with the two-layer blank filter in the removal of turbidity and biological organisms. All experiments were performed using standard methods and the results were evaluated by statistical tests. In the good padding situation and when using water and air backwash system, the removal efficiencies obtained by the multi-layered filter for turbidity, diatome, algae, and nematode were 92.4, 97.8, 97.6, 94.4, and 96.5%, respectively. The removal efficiencies achieved by the two-layer blank filter were 88.8, 85.2, 86.7, 80.5, and 72.1%, respectively. Water and wastewater companies, consultants and manufacturers are recommended to consider the multi-media filters as a preferrable alternative for designing new water treatment plants or for renewing existing plants.
