화학공학소재연구정보센터
Journal of Chemical Technology and Biotechnology, Vol.95, No.1, 20-26, 2020
Potential toxicity and implication of halogenated byproducts generated in MBR online-cleaning with hypochlorite
Online chemical cleaning of membrane bioreactor (MBR) with sodium hypochlorite (NaClO) has been extensively applied for membrane fouling mitigation. However, it was recently revealed that residual NaClO from the online cleaning of MBR caused serious microbial lysis with the subsequent formation of dissolved organic matter (DOM), in which a substantial level of halogenated byproducts was detected. Different from those generated in potable water chlorination, most of the halogenated byproducts generated during MBR online cleaning with hypochlorite belonged to the haloaromatic family, which were apparently more toxic than aliphatic compounds. It was shown that a substantial amount of the generated halogenated byproducts passed through the microfiltration membrane and entered the surface waters through the discharge of MBR permeate. As such, the concentration of halogenated byproducts might likely reach an alarming level via bioaccumulation in the aquatic environment. This emerging situation indeed poses serious concerns for the aquatic environment, water supply and public health due to significantly high toxicity of haloaromatic compounds produced. Unfortunately, the potential halogenated byproducts-associated environmental risks have not been carefully and systematically assessed towards the establishment of relevant regulations. Therefore, this review attempted to fill up such a gap by providing the insights into the potential environmental impacts of halogenated byproducts in the MBR permeate. (c) 2019 Society of Chemical Industry