Nature-based active Rootzone biofilter with Phragmites australis/communis plant species for efficient treatment of oil-contaminated sludge/wastewater and recirculation of purified water. The mass removal of mineral oil from water averaged > 88% (95% Cl± 20%). Implementation of the Rootzone technology will, in addition to water purification, contribute to carbon capture and storage, release of oxygen and clean water to the atmosphere, increased biodiversity, lower the temperature in tropical and subtropical climate zones.