Method for purifying domestic, agricultural and industrial wastewater

摘要

A tank is divided into two half-tanks (2 and 2') by a vertical wall. Said half-tanks are used alternately. The wastewater (3) trickles down through beds of sand (4) and gravel (5) with a grain size that increases in a downward direction. Apart from on its bottom, the tank is covered with a polyvinyl chloride film (6). The bottom of the tank is lined with parallelepiped blocks (7) consisting of the same material which are regularly provided with recesses for collecting the wastewater that has trickled down (3'). Air can also circulate (8) by means of two vertical chimneys (9). The wastewater to be purified is spread evenly over the entire surface of the tank by a device comprising a batch pump (10) and a sprinkler (11). Rushes (Phragmitis australis) (12) are planted in the top sand. The purification process is carried out by aerobic bacteria during the trickling down process. Said bacteria are able to survive by virtue of a combination of superposed gravel beds, the circulation of air in the lower part and the action of the rushes (Phragmitis australis).