The high scientific standards maintained by AQUA in its papers owe much to the continuing dedication of the journal's referees, who give freely of their time and expertise. IWA Publishing is pleased to pay tribute to this contribution by recognizing those who have participated in the review process. Thus, the Editors of AQUA acknowledge with particular gratitude the following referees who have reviewed papers during the period January 2020-December 2020.
| Ismail Abdelaty | Ning Dai | Huan Huan | Majid Mirzaei | Wenjun Sun |
| Hadi Abdollahi | Moustafa Darweesh | Chihpin Huang | Sanjeeb Mohapatra | Yuepeng Sun |
| Siraj Abdulahi | Lassâad Dassi | Wei Huang | José Mondéjar-Jiménez | C. Suribabu |
| Mostafa AbuKhadra | Michelle DeHaan | Yuan Huang | Maung Myint | Monir Takla |
| Kushal Adhikari | Jing Deng | P.S. Husband | Tufa Nagawo | Chaoqun Tan |
| Mansoor Ahammed | Tianan Deng | Jan Ilavsky | Mohammad Najafi | Hao Tang |
| Iman Ahmadianfar | Lihua Dong | Pernille Ingildsen | Thi Thuy Ngo | Vaibhav Thakkar |
| John Akudago | Caetano Dorea | Rehan Jamil | Khoi Nguyen | Nádia Torres |
| Jagadeesh Kumar Alagarasan | Kun Du | Vaclav Janda | Junfeng Niu | Marco Torresi |
| Ramunė Albrektienė | Weili Duan | Martin Jekel | Kwabena Abrefa Nketia | Dang An Tran |
| Stefano Alvisi | Robert Duda | Hatem Jemmali | Odafivwotu Ohwo | Nemanja Trifunovic |
| M. G. Mostofa Amin | Alper Elci | D.C. Jhariya | Gustaf Olsson | Konstantinos Tsagarakis |
| Francisco Arregui de la Cruz | Hamza Elfil | Ren Dong Ji | Toritseju Omaghomi | Stavroula Tsitsifli |
| Erik Arvin | A.S. Eltaweil | Klaus Johannsen | Yaser Ostovari | T Türk |
| Mari Asami | Ahmed El-Zeiny | Bong Seog Jung | Roger Pacheco-Castro | Tomi Turner |
| Vassilis Aschonitis | Adel Emadzadeh | Santosh Kaini | Bin Pan | Kamil Urbanowicz |
| Biniam Ashagre | Miraç Eryiğit | Marko Kallio | Jizheng Pan | Marco van Dijk |
| Abiodun Ayandele | Saeid Eslamian | Vasilis Kanakoudis | Hitesh Panchal | Meine Peter van Dijk |
| Mesfin Ayele | Qadir Esmaili | I.Ethem Karadirek | Laurel Passantino | Petra Vasatova |
| Amin Bagheri | Liangxin Fan | Konstantinos Katsifarakis | Sandhya Rao Poleneni | Ioanna Vasiliadou |
| Danka Barlokova | Wei Fan | M.R. Kavianpour | Alina Pruss | Ina Vertommen |
| Lisa Barrott | Marco Ferrante | Tasneem Gul Kazi | Francesco Pugliese | Lukas Vlcek |
| Rolf Baur | David Ferras | Alireza Keramat | Raido Puust | Jan Vreeburg |
| Ahmet Baylar | Petr Filip | Joshua Kibet | M. Habibur Rahman | Kun Wan |
| Shishir Kumar Behera | Monika Filipenska | Petr Klusoň | Subecha Rai | Wuyi Wan |
| Kourash Behzadian | Louise Fletcher | Ivana Kopecka | S. Rangabhashiyam | Wenlong Wang |
| Prosun Bhattacharya | Marco Franchini | Ioannis Kougias | Goutham Rangarajan | Jianlong Wang |
| Omer Bilhan | Kein Gan | Beata Kowalska | Saman Rashidi | Qiongfang Wang |
| Cristiana Bragalli | Jinliang gao | Franz Krause | Dwarika Ratha | R. Wang |
| Stefano Brighenti | Elkhadir Gharibi | Izabela Krupinska | Badri Narayan Ravikumar | Saige Wang |
| Isobel Brink | Roghaye Ghasempour | Malgorzata Kutylowska | Eldon Rene | Yanhua Wang |
| Joel Bruneau | Amir Gholipour | Zhounian Lai | Ali Rezaei | Zhaohui Wang |
| Bruno Brunone | Dra Leda Gianuzzi | Martti Latva | Janis Rubulis | Nan Wei |
| Laura Bulgariu | Jerome Gilbert | Markus Lechner | Sumiyyah Sabar | Yinhu Wu |
| Daniele Buono | Balendu Shekher Giri | Dunzhu Li | Mohammad Reza Safaei | Kunlun Xin |
| Andrea Capodaglio | Sudha Goel | Ke Li | Mostafa Safdari Shadloo | Lu Xing |
| Nelson Carriço | Tingting Gong | Jr-Lin Lin | Hiroshi Sakai | Jiale Xu |
| Cem Çetinkaya | Francisco González Gómez | Haixing Liu | Miguel Sandoval | Tien Yee |
| Kwok-wing Chau | Marjan Goodarzi | Jiemin Liu | Mohan Sankaralingam | Qidong Yin |
| Tong-Chuan Che | Neil Grigg | Jun Liu | Ajeng Arum Sari | Xiaodong Yu |
| Kuan-Chung Chen | Igor Grigoryev | Shuming Liu | Raju Sekar | Sarvin Zamanzad-Ghavidel |
| Zhuo Chen | Jenny Gronwall | Krishnanand Maillacheruvu | Omid Seyedashraf | Wei Zeng |
| Hongguang Cheng | Hongguang Guo | Sandip Mali | Saroj Sharma | Haiyang Zhang |
| Yong-guang Cheng | Brent Haddad | Nuno Martins | Baoyou Shi | Haoran Zhang |
| Shakhawat Chowdhury | Amir Hatamkhani | Reza Mastouri | Lin Shi | Junzhi Zhang |
| Shipeng Chu | Kai He | José Matos | Yunhong Shi | Kefeng Zhang |
| Yi-Hsueh Chuang | Lijun He | Gagan Matta | Ashok Kumar Singh | Hongying Zhao |
| Tai-Shung Chung | Rita Henderson | Dena McMartin | Marcos Solache-Rios | Yanxia Zhao |
| Luciano Coccagna | Wen-Che Hou | Peter Melville-Shreeve | Cuizhen Sun | Hongxing Zheng |
| Lucas da Silva | Zhenhu Hu | Fanlin Meng | Qiang Sun |
