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Assessing the Impact of Algal Organic Matter on the Performance of Biological Filtration Systems
Citation:
Jeon, Y., J. Calvillo, L. Li, H. Ryu, J. Santo Domingo, O. Choi, J. Brown, AND Y. Seo. Assessing the Impact of Algal Organic Matter on the Performance of Biological Filtration Systems. WQTC 18, Canada, Ontario, CANADA, November 11 - 15, 2018.
Impact/Purpose:
Most drinking water treatment processes that rely on conventional treatment methods such as coagulation/flocculation and media filtration, have proven to be unsuccessful in the removal of cyanotoxins. Thus, source water contaminated by cyanotoxins as secondary metabolites and algal organic matter (AOM) during harmful algal blooms (HABs) is a cause of concern for drinking water treatment professionals. Among the various treatment methods used to control cyanobacterial toxins, adopting a biological filtration system (BFS) has garnered interest due to its low maintenance and potential to degrade or transform various contaminants. Numerous studies have reported that a high removal efficiency of cyanotoxins can be expected only if a system was biologically activated, which is also closely associated with the role of biofilms in the system. As biofilm formation and its activity are affected by many operational and water quality parameters, understanding the role of biofilm in BFS is essential but remains limited, especially for cyanobacterial toxins.
Description:
Most drinking water treatment processes that rely on conventional treatment methods such as coagulation/flocculation and media filtration, have proven to be unsuccessful in the removal of cyanotoxins. Thus, source water contaminated by cyanotoxins as secondary metabolites and algal organic matter (AOM) during harmful algal blooms (HABs) is a cause of concern for drinking water treatment professionals. Among the various treatment methods used to control cyanobacterial toxins, adopting a biological filtration system (BFS) has garnered interest due to its low maintenance and potential to degrade or transform various contaminants. Numerous studies have reported that a high removal efficiency of cyanotoxins can be expected only if a system was biologically activated, which is also closely associated with the role of biofilms in the system. As biofilm formation and its activity are affected by many operational and water quality parameters, understanding the role of biofilm in BFS is essential but remains limited, especially for cyanobacterial toxins. In this study, five lab-scale column reactors filled with GAC/sand were operated continuously to monitor the effects of AOM on the role of biofilm formation and subsequent cyanobacterial toxin (microcystin-LR (MC-LR)) removal. To track the removal of dissolved organic matter (DOM) by filtration, fluorescence excitation emission matrix (FEEM) spectroscopy was used. In addition, the impact of AOM inoculation on the microbial community dynamics was investigated using high-throughput 16S rRNA gene sequencing. The resulting paired-end sequences were merged and analyzed using USEARCH 8.1 and QIIME software, respectively, and further statistical analyses were conducted using R software. The target concentration of MC-LR used in this study was 5μg·L-1. AOM was obtained from a natural bloom that occurred in Lake Erie during the summer of 2017. Overall, AOM in the filter influent can stimulate biofilm formation on GAC and significantly change filter performance. Moreover, a relation between toxin removal and biofilm formation on filter media was also observed.