US Patent 7754079 Plant-based sewage treatment system for purifying wastewater

The invention relates to a plant-based sewage treatment system for purifying waste water including at least one planter, a supply unit which supplies waste water to be purified to the plant-based sewage treatment system, a discharge unit for discharging purified water from the plant-based sewage treatment system, and plants placed inside the planter. The plants are arranged, without a substrate, inside the planter. At least a portion of the planter is situated on a building roof. A space is provided between the planter and the building roof and an exchange medium from the building can be flowed through the space.