REVIEW ARTICLE Efficient technologies for carwash wastewater treatment: a systematic review Mohammad Sarmadi 1,2 & Maryam Foroughi 1,2 & Hossein Najafi Saleh 1,2 & Daryoush Sanaei 3 & Amin Allah Zarei 1,2 & Mina Ghahrchi 2,4 & Edris Bazrafshan 1,2 Received: 4 November 2019 /Accepted: 15 June 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Carwash wastewater (CWW) is considered as an important source of either water pollution or water consumption. Therefore, its treatment is critical not only from the prevention of environmental contamination but also from the recycling of such high-volume water source. Unfortunately, the effective treatment of CWW is almost unknown, complex, and expensive. To overcome the former challenge, this study aimed to systematically review different technologies for CWW treatment. For this, a comprehensive literature survey was conducted and 48 research articles were found suitable to be included in the investigation. The included studies were of coagulation and adsorption (n = 5), membrane-based technologies (n = 15), and electrochemical (n = 11) and combined (n = 17) systems. This comprehensive review showed that the treatment methods of advanced filtration membrane techniques, electrical and chemical coagulation, and advanced oxidation processes can be effective in the removal of pollutants from carwash wastewater (CWW). The mining of different studies, however, showed that the combined methods are the most promising option in the remediation of such wastewater. Keywords Carwash wastewater . Treatment technology . Coagulation and adsorption . Membrane separation . Systematic review Introduction Currently, less than 3% of the Earth’ s water supply is readily usable for human being activities (Tagliabue et al. 2014). Water crisis, therefore, sounds to be one of the most important global issues. Moreover, water demand has increased with the passage of time due to the rapid industrialization and population growth. The limitation of water resources especially in populated areas and arid regions calls for pursuing the appropriate strategies for wastewater reclamation as well as seawater desalination (Liu et al. 2013). Therefore, great efforts have been undertaken on the development of technologies that can acquire freshwater from graywater such as wastewater effluents (Tagliabue et al. 2014). Indeed, adopting such strategies not only could compensate for the water shortage crisis but also prevent ecosystems from col- lapsing due to entrance of different wastewaters. Therefore, it seems that the appropriate treatment of different kinds of waste- waters and their subsequent recycling can overcome water short- age problems and prevent environmental contamination to a greater extent (Rodriguez Boluarte et al. 2016). Industrial wastewaters including textiles, paper, dairy prod- ucts, food industry, and carwashes are considered as the most important sources of water pollution even in low volumes, of which carwash (CW) industry has attracted considerable at- tention to be treated and recycled. For this reason, worldwide environmental legislation and guidelines concerning this spe- cific subject have been released (Zaneti et al. 2011). The ex- ponential growth in car washing facilities number and then the volume of water consumption turns this type of graywater to a Mohammad Sarmadi and Maryam Foroughi contributed equally to this work. Responsible Editor: Philippe Garrigues * Edris Bazrafshan ed_bazrafshan@yahoo.com 1 Department of Environmental Health Engineering, School of Health, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran 2 Health Sciences Research Center, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran 3 Department of Environmental Health Engineering, Faculty of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran 4 Department of Environmental Health Engineering, Torbat Jam Faculty of Medical Sciences, Torbat Jam, Iran Environmental Science and Pollution Research https://doi.org/10.1007/s11356-020-09741-w