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 0.3 mg L-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 x 10(6) cells L-1, more than 98% of algae can be removed with a coagulant dosage of 13 mg L-1. When the algae density is increased to more than 10 x 10(6) 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 20 mg L-1 and 4.0 mg L-1, respectively. (C) 2010 Elsevier B.V. All rights reserved.