Enhanced algae removal by drinking water treatment of chlorination coupled with coagulation

Overgrowing algae have brought negative impacts on daily production of water plants which are rarely eliminated by common methods. To efficiently remove algae from drinking water, a strengthening process or combined process of coagulant and chlorine, and with the dosage of potassium permanganate 0.3mgL−1 is investigated on three selected water supply and purification plants during the algae outbreak period. The results show that the algae density increases with the increase of water temperature. When the algae density in raw water is less than 1.0×106 cells L−1, more than 98% of algae can be removed with a coagulant dosage of 13mg L−1. When the algae density is increased to more than 10×106 cells L−1, i.e. during algae outbreak period, 96% or more algae can be removed using the coagulant and chlorine of dosages of approximately 20mg L−1 and 4.0mg L−1, respectively. ► The concentration of algae would increase as the water temperature increases. ► Drinking water treatment during the algae outbreak period. ► Enhanced removal of algae with the addition of coagulant, chlorine and potassium permanganate.