Harmful algal blooms (HABs) are a major public health concern. In 2014, in Toledo, Ohio, USA, a “Do Not Drink/Do Not Boil (DND/DNB)” was ordered due to the detection of cyanotoxins in the finished water. This incidence caused major concerns and triggered the need for urgent attention to managing cyanotoxins in sources of drinking water supply and engineered water treatment plants impacted by HABs. Conventional drinking water treatment processes may not always be able to fully remove cyanotoxins, especially during massive HAB events. So more advanced water treatment technologies need to be considered and evaluated for their efficiency as an additional barrier(s) to eliminate cyanotoxins from sources of water supply. Our previous studies found UV/chlorine process could degrade and detoxify microcystin-LR (MC-LR) with higher efficiency and larger application range than chlorination or UV/H<sub>2</sub>O<sub>2</sub>. However, since other MCs variants (i.e., MC-RR, MC-LA) are also ubiquitous and toxic, a better understanding of less studied MCs with different amino acid moieties is needed. This study reports results on the UV/chlorine process and chlorination alone in the degradation and detoxification of MC-RR, -YR, and -LA. The structure-related MCs degradation kinetics and mechanisms, and generation of disinfection byproducts (DBPs) in HABs impacted water were studied. The role of specific amino acid moieties of corresponding MC variants on the degradation kinetics will be highlighted. Results on the performance of UV/chlorine in different water matrices will also be presented, considering the role of various factors including chloride ion, natural organic matter (NOM), and algal organic matter (AOM) on the degradation of MCs and generation of C/N-DBPs.

Assessment of UV/chlorine process as treatment barrier dealing with HABs impacted water

ACS Fall 2021

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