About this Research Topic
Water represents a key element to sustainable development. Access to safe drinking water and adequate sanitation are among the main current challenges of the modern society due to water scarcity, its growth in demand and the increase contamination of water resources. The protection of human health and aquatic environment should be ensured, through increased effluent wastewater quality, and water conservation through re-use adopting best practices and appropriate technologies.
Furthermore, the presence in water resources of emerging contaminants (ECs), such as pharmaceutical compounds, personal care products and pesticides, has raised a great concern in the last decades due to their persistence in the environment and their chronic toxicological and endocrine disrupting effects on terrestrial and aquatic organisms. Currently, these contaminants are not regulated and are not completely removed by conventional wastewater treatment processes and their fate, behaviour and eco-toxicological effects are often not well understood.
The development of advanced wastewater treatments that are reliable, cost efficient and effective in removing a wide range of pollutants is demanded in order to obtain higher removal efficiencies in wastewater treatment and to meet the more stringent standards. Biological treatment technologies are by far the most widely used for wastewater treatment due to their economic advantages over other treatment processes in terms of capital and operating costs. These processes degrade nutrient compounds and biodegradable organic matter by microorganisms and even bio-mineralise them to simple inorganic molecules such as water and carbon dioxide. They also offer the opportunity to convert waste into renewable energy. Despite these advantages, conventional biological treatment processes often require large areas, and fail to degrade high strength organic wastewater, toxic or recalcitrant compounds, including most ECs, or to produce high effluent quality.
To overcome the disadvantages of conventional biological processes, innovative and more effective biological treatments are required. In this framework, advanced biotechnologies have emerged such as aerobic granular sludge (AGS) processes and membrane bioreactors (MBR). AGS technology relies upon the formation of microorganisms, selected to grow in granules rather than flocs, held together by a self-produced exopolymeric matrix. The main features of this technology are the excellent settling ability, the dense and strong microbial structure, the ability to withstand high organic loading rates and the high tolerance to toxicity. MBR reactors, combining biological processes with physical separation by membrane filtration, allow high effluent quality, low production of excess sludge and small reactor volume. Nowadays, advanced MBR processes are developing in order to control membrane fouling and increase the performance of this technology.
The integration of biological treatments and advanced oxidation processes (AOPs), such as ozonation, ozonation/UV and ozone/hydrogen peroxide, is also needed to treat wastewater characterized by recalcitrant organic substances in order to transform them, through the generation of hydroxyl radicals, into final products more easily biodegradable by means of subsequent biological treatment. Thereby, these combined processes allow the removal of a wide range of ECs.
In this framework, the Research Topic welcomes articles that broadly address recent developments in the following areas:
• Innovative biological processes such as aerobic granular sludge and advanced membrane bioreactor technology;
• Integration of biological processes and advanced oxidation processes (AOPs);
• Removal of emerging contaminants through the former treatment processes.
Keywords: biological processes, emerging contaminants, innovative biotechnologies, integrated processes, wastewater treatment
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.