Nanobubbles in water and wastewater treatment systems: Small bubbles making big difference

Mingyi Jia; Muhammad Usman Farid; Jehad A Kharraz; Nallapaneni Manoj Kumar; Shauhrat S Chopra; Am Jang; John Chew; Samir Kumar Khanal; Guanghao Chen; Alicia Kyoungjin An

doi:10.1016/j.watres.2023.120613

Nanobubbles in water and wastewater treatment systems: Small bubbles making big difference

Water Res. 2023 Oct 15:245:120613. doi: 10.1016/j.watres.2023.120613. Epub 2023 Sep 11.

Authors

Affiliations

¹ School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region.
² School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region. Electronic address: mufarid@cityu.edu.hk.
³ School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region; Department of Chemical and Petroleum Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, UAE.
⁴ School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region; Center for Circular Supplies, HICCER - Hariterde International Council of Circular Economy Research, Palakkad, Kerala 678631, India.
⁵ Department of Global Smart City, Sungkyunkwan University (SKKU), 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Republic of Korea.
⁶ Department of Chemical Engineering, University of Bath, Bath BA2 7AY, UK.
⁷ Department of Molecular Biosciences and Bioengineering, University of Hawai'i at Manoa, 1955 East-West Road, Honolulu, HI 96822, United States.
⁸ Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution and Water Technology Center, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
⁹ School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region. Electronic address: alicia.kjan@cityu.edu.hk.

PMID: 37738940
DOI: 10.1016/j.watres.2023.120613

Abstract

Since the discovery of nanobubbles (NBs) in 1994, NBs have been attracting growing attention for their fascinating properties and have been studied for application in various environmental fields, including water and wastewater treatment. However, despite the intensive research efforts on NBs' fundamental properties, especially in the past five years, controversies and disagreements in the published literature have hindered their practical implementation. So far, reviews of NB research have mainly focused on NBs' role in specific treatment processes or general applications, highlighting proof-of-concept and success stories primarily at the laboratory scale. As such, there lacks a rigorous review that authenticates NBs' potential beyond the bench scale. This review aims to provide a comprehensive and up-to-date analysis of the recent progress in NB research in the field of water and wastewater treatment at different scales, along with identifying and discussing the challenges and prospects of the technology. Herein, we systematically analyze (1) the fundamental properties of NBs and their relevancy to water treatment processes, (2) recent advances in NB applications for various treatment processes beyond the lab scale, including over 20 pilot and full-scale case studies, (3) a preliminary economic consideration of NB-integrated treatment processes (the case of NB-flotation), and (4) existing controversies in NBs research and the outlook for future research. This review is organized with the aim to provide readers with a step-by-step understanding of the subject matter while highlighting key insights as well as knowledge gaps requiring research to advance the use of NBs in the wastewater treatment industry.

Keywords: Nanobubble aeration; Nanobubble flotation; Nanobubble technology; Nanobubbles; Water and wastewater treatment.

Publication types

Review