Dear Colleagues,

Resource scarcity is the most important driver behind circular economy (CE). Fresh and clean water scarcity, increasing water consumption and climate change will cause a global water crisis in the coming years. Furthermore, in the framework of the CE concept, wastewater treatment plants (WWTPs) must become “ecologically sustainable” technological systems, that means more efficient, less energy demanding and capable of supporting resource and energy recovery. At the same time, WWTPs must maintain their fundamental role, that is to provide a constant and adequate water pollution control, so as to protect human health and the quality of the environment against conventional and emerging contaminants.

This Special Issue focuses on the management of water and wastewater from a CE perspective, concerned with the optimization of water consumption, and resource and/or energy recovery from wastewater and sewage sludge, and we encourage contributions that refer to:

• strategies for water saving in agriculture, industry and household activities;
• strategies for wastewater reuse in agriculture, industry and household activities;
• resource recovery and bio-refinery approaches, aimed at extracting value-added products (including, but not limited to, cellulose, enzymes, bio-plastics, bio-pesticides, proteins, biochar) and nutrients (nitrogen, phosphorous, micronutrients) from wastewater and sewage sludge;
• energy-saving systems in WWTPs (including, but not limited to, systems used in aeration processes) and energy recovery routes, such as anaerobic digestion (including pre- and intermediate treatments), incineration, pyrolysis, gasification, hydrothermal carbonization (HTC), enhanced digestion using microbial fuel cells and hydrogen production.

Original research papers and critical reviews will be considered. All scales of application will be well received.

Dr. Barbara Ruffino
Dr. Katarzyna Pietrucha-Urbanik
Guest Editors

Dr. Giuseppe Campo
Guest Editor Assistant

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Resources is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• clean water and sanitation
• wastewater treatment
• water reuse
• resource recovery
• water-to-energy nexus
• energy saving
• energy recovery