Control of Nuisance Cyanobacteria in Drinking Water Resources Using Alternative Algae-Blocking Mats

Young-Hyo Kim,Hyuk Lee,En-Mi Gwon,In-Hwan Cho,Baik-Ho Kim,Ha-Kyung Kim

doi:10.3390/w12061576

Young-Hyo Kim, Hyuk Lee + Show 4 more

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https://doi.org/10.3390/w12061576

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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.

Highlights

Cyanobacterial blooms are becoming more globally prevalent due to industrialization, population growth, and global warming [1,2,3,4]
The fluctuations in the cell abundance and dominant species of phytoplankton in the second water intake structure of Paldangho Lake (PIF) caused by changes in water temperature and precipitation during the study period are illustrated in Figure 3 and Table 2
The cell abundance increased to 23,136 cells/mL between 21 July and August when the water temperature was beyond ◦ C, while three cyanobacteria (Microcystis aeruginosa, Dolichospermum crassum, and Merismopedia tenuissima) became dominant with a relative abundance of over 90%

Summary

Introduction

Cyanobacterial blooms are becoming more globally prevalent due to industrialization, population growth, and global warming [1,2,3,4]. In August 2014, tap water supplies was suspended in Toledo, Ohio, USA, due to cyanobacteria poisoning [6]. Eutrophication is rapidly spreading in many rivers and lakes, of which 72% are mesotrophic and 22% are eutrophic, with cyanobacteria blooms occurring from summer to winter [7]. Paldangho Lake, which is a major raw water source for over 20 million residents in Seoul and Gyeonggi, is experiencing rapid eutrophication and resulting frequent cyanobacterial blooms due to its large drainage area and a constant inflow of domestic sewage, agricultural effluent, and livestock wastewater [8]

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