As water is an essential resource for life on Earth, securing adequate fresh water for all life and human activities is the most important driving force behind sustainable development. The world is increasingly turning its attention to the issue of water scarcity and the need for fresh water is at the top of the international agenda of finding solutions to this critical problem. The recent advancements made in water treatment science and technology research have alleviated the stress caused by water scarcity by addressing the problems with high quality and sustainable water supply.

Different approaches are taken with respect to water treatment, e.g., coagulation/flocculation, sedimentation, filtration, disinfection, sludge drying, fluoridation, and pH correction. The use of these approaches depends on the type of water to be treated. Thus, in this issue we welcome papers on developed and novel materials and new treatment technologies for water treatment. We also encourage the submission of review articles, which describe the current technology used in or developed for water treatment.

Potential topics include but are not limited to the following:

• The development and applications of hybrid materials for wastewater treatment
• Organic-inorganic, organic-organic, or inorganic-inorganic hybrid materials for wastewater treatment
• Physically blended materials for wastewater treatment
• Polymer or biological composites/blends as adsorbents for wastewater treatment
• Coagulation/flocculation of wastewater using composite or hybrid materials
• Polymer membrane separation technologies in wastewater
• Ion exchange and carbon composites for wastewater treatment technologies