In this respect, the modeling of the organic matter removal kinetics from municipal sewerage in horizontal subsurface flow CWs was carried out using a conventional first-order model and sigmoidal k-n model [[12]]. Water is an essential natural compound on earth; all life forms on our planet need water to function properly. The presented water management research in this Special Issue aimed to assess natural water quality in different areas, i.e., Brazil, Palestine, and China. [Extracted from the article]