Water quality is an important issue and its degradation is a major threat for everyone. A large quantity of water is wasted as wastewater arising from several activities such as industrial, agricultural, and so on. The environmental pollution arising from the discharge of untreated wastewater is increasing and the quest for finding different water treatment methods is highly encouraged. In this special issue of this journal we are seeking to highlight the new studies and researches covering our topic.

Potential topics include, but are not limited to:

• New techniques for water and wastewater treatment
• Methods for water analysis and water quality monitoring
• Development of different materials for wastewater treatment
• Application of nanotechnology in wastewater treatment process
• Case studies for the application of adsorption process for real wastewater treatment
• Optimization of the treatment process
• Activated carbons for wastewater treatment
• Production of biofilters
• Reuse of treated water and its environmental impact
• Economic aspects of production and use of treated water
• Risk analysis in treated water applications
• Sources of water and wastewater
• Contaminants in water and wastewater
• Water quality standards and regulations
• Biological wastewater treatment: bioremediation, phytoremediation, and mycoremediation
• Microbial fuel cells for wastewater treatment
• Zero liquid discharge
• Brine treatment