Alum and Lime-Alum Removal of Toxic and Nontoxic Phytoplankton from the Nile River Water: Laboratory Study

No phytoplankton should be present in treated drinking water because of its potential for bad odor and toxins that may pose hazards to animals and humans upon consumption. This study describes the efficiency of alum and lime-alum treatments for removing phytoplankton from the Nile river water used as a source of drinking water in Egypt. The results showed that alum could not precipitate all phosphate nor coagulate bloom forming cyanobacteria present in the water sample. On the other hand, lime-alum treatment precipitated much more phosphate than alum, and coagulated all phytoplankton present in the water samples including those that could not be coagulated by alum. Furthermore, lime-alum treatment did not change the pH of the water during all the experiment period. Hence, it is suggested that lime-alum be used instead of alum during water treatment processes in Egypt. Copyright Kluwer Academic Publishers 2001