Sustainable Solutions for Wastewater Treatment Management—Microbial Ecology and Biotechnological Applications in the Context of Circular Economy

Dear Colleagues,

The rising demands of the expanding human population have led to an increased use of water resources for household, agricultural, and industrial needs, which leads to an increased wastewater production.

All around the world the annual production of sludge reaches 45 million tons of dry matter, while in the European Union the respective production varies between 10 and 13 million tons dry matter, related to the almost 55 billion cubic meters of wastewater produced on the European continent and the 360 billion cubic meters produced worldwide. These numbers are alarming regarding the urgent need to protect the environment, through the application of conventional and newly developed treatment systems and methods, but also highlight the vast biotechnological potential related to the presence of both nutrients and microorganisms of outstanding diversity. Only recently the United Nations Economic Commission for Europe (UNECE) reported that in year 2050 globally the waste production will further increase reaching an annual high of 3.4 billion tones. The European Green Deal and one of its main pillar the Circular Economy Action Plan has introduced a whole new approach, which extends to the pressing need for the implementation of sustainable water, waste and wastewater treatment solutions to ensure that resources are retained in the system and treated as sources of recovered materials, components, enzymes and renewable energy.

The effective treatment of the produced wastewater and the reduction of water scarcity are closely linked to the effectiveness of the applied treatment methods (ideally sustainable nature-based) and the possibility of reusing the discharged water when necessary. Additionally, the presence of bioactive substances in various types of wastewater and the enzymatic activity of certain microbial species offer a cost-effective and environmentally friendly solution for the degradation of pollutants. This itself contains a growing interest and a broad research field towards the exploration and exploitation of the diverse biotechnological applications of specific groups of microorganisms. It also provides the possibility of treating the effluents of treatment systems as materials that are not discharged in the environment as waste, but instead are further used in a variety of applications, for example in agriculture.

For this Special Issue of Sustainability—Sustainable Solutions for Wastewater Treatment Management—Microbial Ecology and Biotechnological Applications in the Context of Circular Economy—we welcome manuscripts focusing on

• sustainable wastewater treatment
• microbial ecology of activated sludge
• simulation and management of water (numerical and data-driven)
• wastewater and coastal systems
• removal of micropollutants
• sludge treatment
• WWTP efficiency assessment
• health status monitoring and modeling of the receiving water bodies
• wastewater reuse practices and legislation
• biotechnological applications in pollutants removal

We look forward to receiving your contributions.

Dr. Nikolaos Remmas
Prof. Dr. Cristina Sousa Coutinho Calheiros
Prof. Dr. Petros Gikas
Guest Editors

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• wastewater management
• bioremediation
• microbial ecology
• constructed wetlands
• water & wastewater treatment
• circular economy