Patent FR-2966143-A1 (FR)
Title: Wastewater treatment plant for purifying domestic/industrial used water, comprises inlet pipe for effluent to be purified, purification tank with external wall having cylinder shape in vertical axis, and outlet pipe for purified effluent
Inventor: VACHE ALAIN
IPC: C02F3/00
Filed: 2010-10-19
Abstract: The wastewater treatment plant (1) comprises an inlet pipe (4) for an effluent to be purified, a purification tank (2) with an external wall (3) having a cylinder shape in vertical axis, an outlet pipe (5) for the purified effluent, annular channels for circulating effluent to be purified, a fluid contact unit, and a unit for recirculating sludge. The purification tank is divided into three adjacent compartments from upstream to downstream, where the compartments include a pre-settler, a biological reactor and a post-settler. The wastewater treatment plant (1) comprises an inlet pipe (4) for an effluent to be purified, a purification tank (2) with an external wall (3) having a cylinder shape in vertical axis, an outlet pipe (5) for the purified effluent, annular channels for circulating effluent to be purified, a fluid contact unit, and a unit for recirculating sludge. The purification tank is divided into three adjacent compartments from upstream to downstream, where the compartments include a pre-settler, a biological reactor and a post-settler. The pre-settler, the biological reactor and the post-settler are separated by cylindrical shaped partitions and interconnected by the fluid contact unit. The post-settler compartment surrounds the biological reactor compartment that surrounds a central portion of the pre-settler for reducing a thermal shock, which is harmful to the effectiveness of the biological reactor. The compartments of the purification tank are coaxial. The annular channels are placed between the partitions and the external wall of the purification tank corresponding to a peripheral compartment constituting the post-settler and an intermediate compartment constituting the biological reactor. The intermediate compartment and the peripheral compartment are closed by a radial partition constituting the ends of annular channels of the intermediate compartment and the peripheral compartment. The fluid is contacted between the central compartment and the intermediate compartment and between the intermediate compartment and the peripheral compartment. The outlet pipe is arranged in an area adjacent to the radial partition so as to impose an annular path of circulation in an annular pipe of each respective compartment from one end to the other of the pipe. The outlet pipe and the fluid contact unit are arranged alternately on either side of the radial partition so as to impose a clockwise path in one annular compartment and a counterclockwise path in the other annular compartment. The biological reactor is an immersed fixed bed reactor comprising a cellular support material distributed throughout the intermediate compartment. The partitions of the compartments and the radial partition form a monoblock assembly. The external wall of the purification tank is made of concrete. The sludge recirculating unit is provided between a bottom of the peripheral compartment constituting the post-settler and the central compartment constituting the pre-settler.