In the last decade, the concern about the occurrence and impact of contaminants of emerging concern (CECs) is growing worldwide. This fact has resulted in the development of analytical techniques to identify and quantify both CECs and their metabolites, in the improvement of methodologies and strategies to evaluate their associated risk, and in the innovation of more robust, safe, and efficient water treatment technologies even in real-world samples. In this sense, Ibero-American countries are not the exception. On the contrary, nowadays, several seminal works lead by Ibero-American researchers have been conducted, which are also valuable for authorities and policy-makers.

This Special Issue contains selected high-quality works, which provide an overview of state-of-the-art, advances, and challenges in Ibero-American countries regarding the occurrence, impact, and elimination of CECs, particularly in water samples of environmental interest. Therefore, the Issue counts with contributions dealing about the fate of CECs and innovative water treatment alternatives focused in the application of advanced oxidation processes (AOPs), adsorption onto activated carbon, and membrane ultrafiltration, which reports new engineering and/or fundamental developments of the technologies. Heterogeneous photocatalysis, Fenton-based processes, and electrochemical treatments from simulated to real urban wastewater are the AOPs considered in this issue to eliminate CECs. Most of these studies look for the integration or intensification of the process to enhance the performance of advanced treatments.

In total, the 15 articles of this collection, from different Ibero-American countries, experienced a rigorous peer review evaluation, ensuring that the quality of the final manuscripts was the highest, according to the high-grade standards of Environmental Science and Pollution Research.

We would like to thank all authors for their innovative scientific contributions and, in particular, the reviewers whose comments and suggestions were extremely important to achieve high-quality papers, as well as all the editorial team of the journal for their great support since the initial acceptance of our proposal.