Control of nuisance cyanobacteria in drinkingwater resources using alternative algae-blocking mats

Abstract

The water intake facility of Paldangho Lake (PIF), constructed in 1988, supplies drinking water to the Seoul metropolitan area and satellite city (ca. 20 million inhabitants) in South Korea. A nuisance cyanobacterial bloom (CB) has been observed every year in the PIF. Thus, related governments have been funding the control of CBs and algal-originated materials (AOMs). In this study, an algae-blocking mat (ABM) was developed to protect against CBs and AOMs considering temperature and water depth. We evaluated the daily and monthly performance of the ABM on phytoplankton, pH, dissolved oxygen, chlorophyll-a, and light intensity between April and October 2015. Although the average cell abundance of cyanobacteria between July and September approached the warning level of the Korea alert system, the highest algal removal efficiency was recorded as 92% in August when the cyanobacterial cells were over 66,000 cells/mL. On average, the ABM showed a low removal efficiency of 26% on both geosmin and 2-methylisoborneol, whereas total phytoplankton was more than 30%. In conclusion, our results indicate that the ABM may be an economical blocking tool for nuisance cyanobacteria in drinking water resources, considering AOMs and total phytoplankton.