The effect of sedimentation by chemical coagulants and the rapid sand filters on algal removal at drinking water treatment plants in Egypt

Abstract Background The Nile River included diverse phytoplankton compositions belonging to five main categories. Algae have been classified and identified through comparative morphology. Results Pyrrophyta, Charophyta, Cyanophyta, Chlorophyta, Bacillariophyta were presented the full period of investigation with 1, 3, 14, 23, 28 species, respectively. Therefore, it may be important note that diatoms recorded as an abundant group in all investigated samples. numbers ranged between 1.45 × 10 6 1.18 7 Organism/l, this was followed by green algae from 7.0 5 1.22 Organism/l. While lowest count blue-green 1.6 7.03 treatment water using two chemical coagulants "aluminum sulfate (Al 2 (SO 4 ) 3 ⋅16H O) aluminum oxide O )" removed about 85% 90%, As for, Cyanophyceae they completely treated sedimentation, filtration, chlorination process. sedimentation basins 20 100% total algal while rapid sand filters 65 during depends on species algae. Conclusions This study concluded removal more or less easy depending nature prevailing group. Water plants must modify alum chlorine doses their processes according groups, provide aesthetically acceptable biologically safe supply.