Nowadays, an enormous amount of wastewater is generated, whether by industrial or human activities. Wastewater contaminated with toxic compounds can endanger the ecosystem and human health if released into the environment untreated or partially treated. For this reason, polluted industrial wastewater must be effectively treated before it is discharged into the environment. Although conventional wastewater treatment can efficiently reduce nitrogen and carbon concentrations, it is ineffective in removing so-called emerging pollutants (e.g., pharmaceuticals, pesticides, and personal care products). These compounds pass through the wastewater treatment plant unchanged and enter the environment in this way, posing a threat to nature and human life. Many of the emerging pollutants cause endocrine disruption or are carcinogenic. Efficient treatment is therefore urgently needed to remove these compounds before they enter the environment or water bodies. This special issue of the journal CLEAN – Soil, Air, Water includes the latest available technologies to treat industrial wastewater. It covers extensively the advancement in biological treatments, advanced oxidation techniques, and membrane technology to remove water pollutants. Having an easy-to-use guider manual for all the enlisted smart techniques, it also describes and discusses the emerging futuristic technologies in industrial pollutant removal from wastewater. Here, the new and emerging innovative trends in bioremediation of hazardous pollutants present in wastewater are discussed in depth. It also includes the fate of pollutants produced after the treatment process both at the laboratory scale and at the industrial scale. The special issue intrusively explores the unique biological aspects of the wastewater treatment process and highlights the advantages they provide for engineering applications in various industries. Each paper covers a different biological-based approach and examines the basic principles, practical applications, recent breakthroughs, and associated limitations. It presents an array of cutting-edge wastewater treatment research and thereafter its applications in treatment, remediation, sensing, and pollution prevention processes. The biological process for application in wastewater research has a significant impact on maintaining the long-term quality, availability, and usability of water. In this special issue, biological wastewater treatment technologies are explained. The biological processes presented in wastewater treatment processes include: 1) bioremediation of wastewater that includes aerobic treatment (oxidation ponds, aeration lagoons, aerobic bioreactors, activated sludge, percolating or trickling filters, biological filters, rotating biological contactors, and biological removal of nutrients) and anaerobic treatment (anaerobic bioreactors and anaerobic lagoons); 2) phytoremediation of wastewater that covers constructed wetlands, rhizofiltration, rhizodegradation, phytodegradation, phytoaccumulation, phytotransformation, and hyperaccumulators; and 3) mycoremediation of wastewater. The special issue describes a broad area of biological processes and water research which are considered key components for advanced water purification. It also includes the desalination technologies that remove, reduce, or neutralize water contaminants that threaten human health and/or ecosystem productivity and integrity. This special issue is mainly related to each of the main factors contributing to the removal of toxic pollutants from wastewater, namely, methods and procedures, materials (especially low-cost materials originating from industrial and agricultural waste), wastewater management, valorization possibilities of waste resulting from wastewater treatment processes, etc. This special issue is especially devoted to industrial wastewater treatment and aims to present the current state-of-the-art and innovative research that addresses these challenges, so that wastewater treatment systems can adapt and be fit for purpose, robust, and resilient for the next 100 years. It is equally beneficial for students and professors for understanding the new research advancements in this field. The main objective of this special issue is to summarize the work of the eminent scientists in this field to provide a clear but concise chapter that can be used as a quick reference for environmental engineers and researchers, and to be effectively implemented in higher education teaching undergraduate and graduate students, as well as extension and outreach.