Inhibitory Effects of UV-LED Irradiation and Period in Darkness on Photoreactivation of Coliforms in Johkasou Treated Water

Q3 Environmental Science

Journal of Water and Environment Technology Pub Date : 2022-01-01 DOI:10.2965/jwet.22-045

Akihiro Kakiki, O. Nishimura, Hiroshi Yamazaki

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引用次数: 0

Abstract

With the recent development of ultraviolet light emitting diodes (UV-LEDs), it is now possible to apply UV disinfection, previously used only for medium-to-large sized sewage treatment plants, to Johkasou wastewater, a household wastewater treatment system. However, it is known that coliforms that have been inactivated by UV irradiation regain their activity after of sunlight irradiation, etc. Therefore, in small Johkasou, where discharge channels are often open, photorecovery may occur immediately after UV disinfection. However, no studies have been conducted to investigate photorecovery by sunlight after UV disinfection of wastewater from small Johkasou. In this study, the relationship between the photorecovery of coliforms and the dose of sunlight after UV-LED irradiation of effluent in Johkasou was investigated. As a result, we identified the amount of sunlight that will maximize photoreactivation effect. We also clarified the suppressing effect of an excessive amount of sunlight on the photoreactivation phenomenon. Additionally, since it was confirmed that the photore activation effect was suppressed by a certain period of darkness following UV-LED irradiation, it was considered that the photoreactivation effect can also be suppressed by allowing wastewater to reside in darkness for the currently estimated residence time in a disinfection tank.

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UV-LED照射和黑暗时间对约卡苏处理水中大肠菌群光活化的抑制作用

随着紫外线发光二极管(UV- led)的最新发展，以前仅用于大中型污水处理厂的紫外线消毒现在可以应用于家庭污水处理系统Johkasou废水。然而，众所周知，被紫外线照射灭活的大肠菌群在阳光照射后会恢复活性等。因此，在排放通道经常开放的小约翰卡苏，紫外线消毒后可能立即发生光恢复。然而，目前还没有研究对小Johkasou废水进行紫外线消毒后的光回收。本文研究了UV-LED照射约卡苏污水后大肠菌群的光恢复与光照剂量的关系。因此，我们确定了将最大化光活化效果的阳光量。我们还阐明了过量的阳光对光活化现象的抑制作用。此外，由于已经证实UV-LED照射后一定时间的黑暗会抑制光活化效应，因此可以认为，让废水在消毒池中停留在黑暗中，达到目前估计的停留时间，也可以抑制光活化效应。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Water and Environment Technology Environmental Science-Water Science and Technology

CiteScore

1.80

自引率

0.00%

发文量

审稿时长

43 weeks

期刊介绍： The Journal of Water and Environment Technology is an Open Access, fully peer-reviewed international journal for all aspects of the science, technology and management of water and the environment. The journal’s articles are clearly placed in a broader context to be relevant and interesting to our global audience of researchers, engineers, water technologists, and policy makers. JWET is the official journal of the Japan Society on Water Environment (JSWE) published in English, and welcomes submissions that take basic, applied or modeling approaches to the interesting issues facing the field. Topics can include, but are not limited to: water environment, soil and groundwater, drinking water, biological treatment, physicochemical treatment, sludge and solid waste, toxicity, public health and risk assessment, test and analytical methods, environmental education and other issues. JWET also welcomes seminal studies that help lay the foundations for future research in the field. JWET is committed to an ethical, fair and rapid peer-review process. It is published six times per year. It has two article types: Original Articles and Review Articles.