Bioremediation of eutrophic water and control of cyanobacterial bloom by attached periphyton

Abstract

Diverse methods have been applied to control cyanobacterial bloom, but no universal method has been developed. Periphytons (attached microalgae) compete with cyanobacteria for nutrients and thus were cultivated and regularly harvested for nutrient reduction and bloom control. Four mesocosms, with different amounts of supporting materials, were constructed in Daechung Reservoir, Korea. Cyanobacterial growth decreased to one-third by the growth of attached microalgae, as compared to the control mesocosm. The highest periphyton biomass productivity of 111 mg m -1 d -1 was found, corresponding to the removal of 87.4 μg P L -1 in 24 days. Dissolved microcystin concentration was maintained less than 1 μg L -1. Periphytic microalgae grew well even under lower temperatures. Total biomass productivity was lower (25.9 mg m -1 d -1) than in the warmer season but sufficient to reduce the cyanobacterial growth. The developed periphyton cultivation system showed a good potential in terms of nutrient reduction and cyanobacterial bloom control.