A double-layer structure oxidation ditch

Abstract

The invention provides a novel oxidation ditch being of a double-layer structure. The novel oxidation ditch comprises a tank body, wherein the tank body consists of an anoxic tank, an aerobic tank and a secondary sedimentation tank; the tank body is provided with an oxidation-ditch water inlet pipe and a return-sludge water inlet pipe; the oxidation-ditch water inlet pipe and the return-sludge water inlet pipe are connected with the anoxic tank; the aerobic tank and the anoxic tank are formed into an up-down double-layer structure in the tank body; the aerobic tank is of a circular-ring-shaped baffling structure, and is internally provided with a surface aerator; the anoxic tank is of a circular-ring-shaped structure, and is internally provided with an aeration system; a return water way is arranged between the aerobic tank and the anoxic tank; the secondary sedimentation tank is located in the center of the tank body, and is surrounded by the aerobic tank and the anoxic tank; the longitudinal section of the secondary sedimentation tank is of an inverted-T-shaped structure; a water outlet channel of the aerobic tank is connected with a water inlet pipe of the secondary sedimentation tank; the secondary sedimentation tank is internally provided with a sludge scraper; the sludge scraper is communicated with a sludge discharge pipe of the secondary sedimentation tank; the secondary sedimentation tank is also provided with a secondary-sedimentation-tank water discharge pipe and an annular secondary-sedimentation-tank water outlet channel.

Description

technical field [0001] The invention belongs to the technical field of environmental treatment, and specifically relates to a novel double-layer structure oxidation ditch, which is especially suitable for water plants in view of the problems of shallow depth, large floor area, and fast surface heat loss in traditional oxidation ditch process pools using surface aerators. Sewage treatment plants with limited area and cold environment can significantly improve the treatment effect while reducing floor space, investment and operating costs. Background technique [0002] Oxidation ditch, also known as oxidation ditch, is a deformation process equipment based on activated sludge method. Oxygen and aerobic section, so that the organic matter in the sewage can be removed. [0003] The world's first oxidation ditch was designed by Dr. A.Pasveer, using the Kessener rotary brush surface aerator. It was built and put into use in the town of Voorschoten in the Netherlands in 1954, so i...

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Problems solved by technology

However, there is a limitation in the surface aeration method, that is, the immersion depth of the currently used aeration disc should be 0.23-0.53m, the immersion depth of the rotary brush surface aerator is 0.3m, and the immersion depth of the impeller of the vertical shaft aerator is 0.04m It has been proved by research that increasing the immersion depth and linear velocity of the impeller of the surface aeration equipment can help increase the lifting head within a certain range, but excessive immersion depth and rotational speed will lead to a decrease in the horizontal flow rate, which will decrease with the increase of water depth The flow velocity at the bottom of the ditch causes the flow velocity at the upper part of the oxidation ditch to be relatively large, while the flow velocity at the bottom is very small, resulting in a large amount of mud accumulation at the bottom of the ditch (sometimes the thickness of the mud accumulation is ≥ 1.0m), which reduces the effective volume of the oxidation ditch and reduces the treatment effect. Generally, aeration The water depth of the pool must be controlled within 3.5m, otherwise it is very easy to cause sludge accumulation; therefore, the oxidation ditch pool with surface aeration method is shallow and occupies a large area. The large body surface area and the large direct contact area between the water body and the outside world lead to more heat loss and faster cooling, which reduces the water treatment effect; especially in the north, the water temperature in winter is around 10 degrees, which seriously affects the removal of pollutants. This is also an oxidation ditch. Reasons why it is not commonly used in northern regions

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