Application of modified qualitative index for surveillance of water-filtration process in turbidity removal by different media

• Published in: International journal of environmental science and technology (Tehran) 2012-10, Vol.9 (4), p.691-700
• Main Authors: Badalians Gholikandi, G., Noorisepehr, M., Dehghanifard, E., Koolivand, A., Dehnavi, A., Moalej, S.
• Format: Article
• Language: English
• Subjects: Aggregates; Aquatic Pollution; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Science and Engineering; Original Paper; Silica; Soil Science & Conservation; Surveillance; Waste Water Technology; Water filtration; Water Management; Water Pollution Control
• ISSN: 1735-1472; 1735-2630
• DOI: 10.1007/s13762-012-0026-x

Several media have been used in treatment plants, however, their efficiency for turbidity removal, which is determined by qualitative indices, has been considered. Current qualitative indices such as turbidity and escaping particle number could not completely measure the efficiency of the filtration system; therefore defining new qualitative indices is essential. In this study, the efficiency of two different dual media filters in turbidity removal was compared in different operating condition using qualitative indices. The pilot consisted of a filter column (1-m depth) in which the filter-1 was consisted of a layer of anthracite (450-mm depth) and a layer of silica sand (350-mm depth); and filter-2 had the same media characteristics except for the first layer that was light expanded clay aggregates (LECA). Turbidities of 10, 20, and 30 NTU, coagulant concentrations of 4, 8, and 12 ppm and filtration rates of 10, 15, and 20 m/h were considered as variables. Results showed that the media of filter-2 is a suitable substitute for the media of filter-1 ( P value