Review Microalgae-based wastewater treatment: Mechanisms, challenges, recent advances, and future prospects Abdallah Abdelfattah a, b, 1 , Sameh Samir Ali c, d, 1 , * , Hassan Ramadan b, 2 , Eslam Ibrahim El-Aswar e, 2 , Reham Eltawab a, b , Shih-Hsin Ho f, ** , Tamer Elsamahy c , Shengnan Li f , Mostafa M. El-Sheekh d , Michael Schagerl g , Michael Kornaros h , Jianzhong Sun c, *** a School of Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, PR China b Department of Public Works Engineering, Faculty of Engineering, Tanta University, Tanta, 31511, Egypt c Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, PR China d Botany Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt e Central Laboratories for Environmental Quality Monitoring (CLEQM), National Water Research Center (NWRC), El-Kanater,13621, Qalyubiyah, Egypt f State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin,150090, PR China g Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, A-1030 Vienna, Austria h Laboratory of Biochemical Engineering & Environmental Technology (LBEET), Department of Chemical Engineering, University of Patras, 1 Karatheodori Str., University Campus, 26504, Patras, Greece article info Article history: Received 7 May 2022 Received in revised form 1 September 2022 Accepted 1 September 2022 Keywords: Bioremediation Wastewater treatment Environmental applications Microalgae Co-culturing abstract The rapid expansion of both the global economy and the human population has led to a shortage of water resources suitable for direct human consumption. As a result, water remediation will inexorably become the primary focus on a global scale. Microalgae can be grown in various types of wastewaters (WW). They have a high potential to remove contaminants from the effluents of industries and urban areas. This review focuses on recent advances on WW remediation through microalgae cultivation. Attention has already been paid to microalgae-based wastewater treatment (WWT) due to its low energy re- quirements, the strong ability of microalgae to thrive under diverse environmental conditions, and the potential to transform WW nutrients into high-value compounds. It turned out that microalgae-based WWT is an economical and sustainable solution. Moreover, different types of toxins are removed by microalgae through biosorption, bioaccumulation, and biodegradation processes. Examples are toxins from agricultural runoffs and textile and pharmaceutical industrial effluents. Microalgae have the po- tential to mitigate carbon dioxide and make use of the micronutrients that are present in the effluents. This review paper highlights the application of microalgae in WW remediation and the remediation of diverse types of pollutants commonly present in WW through different mechanisms, simultaneous resource recovery, and efficient microalgae-based co-culturing systems along with bottlenecks and prospects. © 2022 The Authors. Published by Elsevier B.V. on behalf of Chinese Society for Environmental Sciences, Harbin Institute of Technology, Chinese Research Academy of Environmental Sciences. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction Water is an essential resource and a pivotal feedstock in numerous industries, including pharmaceuticals, electronics, food, beverage, petrochemicals, agrochemicals, oil and gas industries, and domestic purposes [1]. The direct disposal of the contaminated water discharged from these applications poses high risks to the environment and is an increasing concern due to its myriad con- taminants. Wastewater (WW) contains various compounds, some * Corresponding author. Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, PR China. ** Corresponding author. *** Corresponding author. E-mail addresses: samh@ujs.edu.cn, samh_samir@science.tanta.edu.eg (S.S. Ali), stephen6949@hit.edu.cn (S.-H. Ho), jzsun1002@ujs.edu.cn (J. Sun). 1 Shared first co-author. 2 Contributed equally to this study. Contents lists available at ScienceDirect Environmental Science and Ecotechnology journal homepage: www.journals.elsevier.com/environmental-science-and- ecotechnology/ https://doi.org/10.1016/j.ese.2022.100205 2666-4984/© 2022 The Authors. Published by Elsevier B.V. on behalf of Chinese Society for Environmental Sciences, Harbin Institute of Technology, Chinese Research Academy of Environmental Sciences. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Environmental Science and Ecotechnology 13 (2023) 100205