Water treatment and purifying apparatus including water softeners; drinking water systems; reverse-osmosis membrane systems and whole-house water filters; water conditioning and purifying systems for residential, commercial and industrial use, comprised of water filters, sterilizing filters, drinking water filters, additive containing filters, and additive containing cartridges; water conditioning and purifying systems for domestic and industrical use, namely storage tanks forming part of reverse osmosis systems; filter media for removing arsenic from water; water purifying and treatment systems comprising filters for removing arsenic from water; and tanks containing filter medial for removing arsenic from water; water filters, water treatment filters and water treatment cartridges in the nature of replacement cartridges for water filtration and purification units; Water filtering units for domestic, commercial, and industrial use; water filters; particulate filtering media for domestic, commercial, and industrial use; wastewater treatment equipment, namely deionization, ion exchange, electrowinning, water recycling, reverse osmosis and filtrations units; water conditioning and purifying systems for domestic and industrial use, namely water softening, membrane filtration, reverse osmosis, ion exchange, and filtering units