Effect of coagulants in removing cyanotoxin-microcystinin drinking water treatment process
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Abstract
The presence of cyanotoxins in source water is a worldwide problem. The most widespread cyanotoxin, called microcystins (MCs), produced from Microcystis Aeroginosa, can cause severe problems to the environment, animals and human health. A standard drinking water treatment process involves coagulation/flocculation process as primary treatment to remove cyanobacteria from source water. In coagulation/flocculation processes, a chemical coagulant is added to source water using rapid/slow mixing to facilitate bonding among particulates. As the process involves chemical and mechanical stress, cyanotoxin may get released to the drinking water.
Coagulation/flocculation process can remove intact cyanobacteria effectively, however, study is limited to show the effect of coagulants in removing cyanotoxins during coagulation/flocculation. Our study would evaluate different types and concentration of coagulants to establish effective methods to remove cyanotoxins at the preliminary drinking water treatment. In this study, a jar test was conducted with microcystin-LR (MCLR) and microcystin-LA (MCLA) to show improved removal. A coagulation/flocculation process was used at laboratory bench scale. This study is important, as it establishes a method that would eliminate harmful cyanotoxins before they enter the secondary treatment process. The results would help drinking water facilities to remove cyanotoxins in the primary treatment where cyanobacteria and their toxins may be found in the source water.