en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering Review Review Article <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:1;">The water and wastewater crisis in developing countries, particularly in rural and peri-urban areas, represents a major public health, social, and economic challenge. Due to financial and infrastructural limitations, implementing of centralized wastewater treatment plants in these regions is often difficult or unfeasible. In this context, Decentralized Wastewater Treatment Systems (DWTS) have emerged as a low-cost, effective, and sustainable solution for wastewater management. These systems rely on simple technologies such as anaerobic filters, constructed wetlands, and biological filters, and are capable of treating domestic, agricultural, and industrial wastewater at small scales. Features such as the use of natural resources and low installation and maintenance costs make DWTS a viable option for areas lacking centralized sewage networks. However, challenges such as financial constraints, the need for local community training, limited available space, and soil conditions must be considered. This study reviews the advantages, challenges, applicable technologies, and successful case studies of DWTS and provides recommendations to enhance the performance and expansion of these systems for water crisis management in developing countries.</span></span></span></div> Decentralized wastewater treatment systems, Water crisis management, Developing countries, Rural wastewater treatment, Sustainable wastewater treatment, 0 0 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-650-4&slc_lang=en&sid=1 Farshad Yaghoubian farshadyaghoubian47@gmail.com 100319475328460016392 0009-0004-6090-9483 No Student Research Committee, Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Mohammad Reza Mehrasbi zmehr@zums.ac.ir 100319475328460016393 100319475328460016393 No Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Esrafil Asgari sasgary@gmail.com 100319475328460016394 100319475328460016394 Yes Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Hossein Arabzade hos.arabzade@gmail.com 100319475328460016395 100319475328460016395 No Student Research Committee, Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Mohammad Amin Abbasian aminoabbasiano@gmail.com 100319475328460016396 0009-0000-1146-4378 No Student Research Committee, Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran.