Following Environmental Science & Pollution Research commitment to the publication of high quality research articles on timely topics in the field of environmental monitoring and protection technologies, this is a special issue containing a selection of seventeen papers based on oral and poster communications from the third European Conference on Environmental Applications of Advanced Oxidation Processes—EAAOP-3.

This time, the meeting was held in Almeria, Spain from the 28th to 30th of October 2013 and was organized under the auspice of Plataforma Solar de Almeria (www.psa.es), in collaboration with CIESOL (www.ciesol.es), a joint research center between the University of Almeria (UAL) and CIEMAT.

The objective of the conference was to bring together scientists, engineers, and other environmental professionals to present their findings and discuss future trends and directions concerning advanced oxidation processes (AOPs). The presentations focused on the scientific and technological advances of AOPs for the remediation of surface water, drinking water, groundwater, municipal, industrial and agro-industrial wastewater, and air and soil contaminated with various recalcitrant compounds, either alone or in conjunction with other processes.

AOPs are expanding their significance to a whole range of scientific applications under which participants from academia, research centers, and small and medium enterprises and industries are able to demonstrate new skills, report new achievements, and share relevant experiences and knowledge. Parallel to scientific significance is important to pass the message about the implications of such matters into everyday people’s life, especially in what concerns clean water accessibility, in a way that governmental decision-makers and company shareholders can be brought to participate.

EAAOP meetings know how to rise to the occasion and the geographical bonds have naturally been broken. The more than 250 participants of the present edition came from 30 countries from different geographical areas including the EU (Austria, Cyprus, France, Germany, Greece, Ireland, Italy, Portugal, Slovenia, Spain, UK, etc), Mediterranean countries (Algeria, Egypt, Israel, Tunisia, Turkey), as well as Brazil, Colombia, India, Mexico, Russia, Serbia, Switzerland, and the USA. They produced a valuable body of information and knowledge, contained in more than 300 oral and poster contributions covering topics such as process fundamentals, reaction kinetics and mechanistic modeling, semiconductor photocatalysis and new materials, UV-based and radiation processes, Fenton and photo-Fenton processes, ozonation technologies, electrochemical processes, wet air oxidation processes, water and air disinfection, AOPs (and combined technologies) for water and soil treatment, AOPs for odor and VOC control, solar-driven applications, tertiary treatments, pilot scale and field applications, monitoring and control of process performance, and other new technology trends.

The collection included in this special issue covers topics such as process combination (e.g., AOPs coupled either together or with separation or biological processes) for the efficient treatment of industrial effluents and emerging microcontaminants, experimental, and modeling studies in pilot-scale, compound parabolic collectors for solar photocatalysis, environmental chemistry and ecotoxicity of transformation by-products, and determination of reactive oxygen species, testing of materials with enhanced catalytic and photocatalytic properties. Classical processes still need improvement: ozonation and photo-Fenton and Fenton-like processes are also dealt with in this issue. All these clearly reflect the multi- and interdisciplinary approach needed to achieve higher levels of performance. It is quite rewarding to see the participation of researchers with different backgrounds working at the interface of science and engineering to understand and develop technologies for water and soil remediation.

This issue was only possible with the generous contribution of the authors and the journal’s editors who handled the submissions. Sixto Malato wishes to thank the Spanish Ministry of Economy and Competitiveness financial support under the AQUAFOTOX Project (Reference: CTQ2012-38754-C03-01) and the AQUASUN Project (Reference: CTM2011-29143-C03-03).