CHEAQS was written by Wilko Verweij. He studied inorganic chemistry at Groningen University where he did a master thesis on speciation of arsenic (1986). From 1986 until 1991, he did his Ph.D. research at the Limnological Institute (subject: speciation of copper in lakes with high content of organic matter). For this thesis, Wilko developed his first speciation program called GECHEQ. Later he continued developing chemical equilibrium models, with special attention for the user friendliness and chemical intuition.
From 1991 until 2017, he worked at the National Institute for Public Health and the Environment. From 2018 until almost 2023 he worked at Deltares. Starting 1 December 2022, he works at the province of Overijssel. CHEAQS is not a product of these institutions.
You can find his LinkedIN-profile here.