Complex sentence: The most common type of domestic treatment unit uses the technologies of adsorption i.e. granular media such as Bayoxide E33, GFH, Titanium Dioxide and reverse osmosis, To a less extent ion exchange and activated alumina have been considered but not commonly used.
Split into simpler sentences: The most common types of domestic treatment use the technologies of adsorption (using media such as Bayoxide E33, GFH, or titanium dioxide) or reverse osmosis. Ion exchange and activated alumina have been considered but not commonly used.