Wang, MHS and Wang, LK (2022). State-of-the-art technologies and terminologies for iron and manganese control. In: “Environmental Science, Technology, Engineering and Mathematics (STEM)”, Wang, LK, Wang, MHS and Pankivskyi, YI (eds.), 2022(12A), STEM-VOL2022-NUM12A-DEC2022. 80 pages. December 2022, Lenox Institute Press, Massachusetts, USA. https://doi.org/10.17613/576t-r212 …. ABSTRACT: This publication covers the subjects of : (a) the sources, environmental engineering significance, environmental impact, types, concentrations and problems of soluble iron Fe (II) and manganese Mn (II) in groundwater, (b) The Cooperative Extension Service (CES), and the Secondary Maximum Contaminant Levels (SMCL) recommended by the US Environmental Protection Agency (USEPA) for iron and manganese in the drinking water; (c) the state-of-the-art technologies for control or removal of iron and manganese; (d) the recommended dosages of various oxidants for conversion of soluble Fe (II) and Mn (II) to their insoluble forms of Fe (III) and Mn (IV), respectively; (e) the US 10 States Standards for design of iron and manganese removal facilities; (f) the advantages and disadvantages of various iron and manganese control or removal processes; (g) the rules of thumbs for process system selection; (h) the latest research and developments (R&D) and call for further research; and (i) all related technical terminologies, such as sequestering chemicals, polyphosphate, sodium silicate, potassium permanganate, oxygen, ozone, chlorine, chlorine dioxide, biological oxidation, aeration, chemical oxidation, catalytic oxidation, filtration, oxidizing filtration, manganese greensand, birm, manganese dioxide filtration media, Pyrolox, Pro-OX, ion exchange, softener, dissolved air flotation (DAF), induced air flotation (IAF), electroflotation (EF), physicochemical sequencing batch reactor (PC-SBR), Mangazur, Ferazur, Advanced Oxidation Process (AOP).