The most complete sewage treatment process introduction

2. Sedimentation tank structure: inlet area and outlet area: make water flow through sedimentation tank evenly, avoid short flow and reduce the adverse impact of turbulence on precipitation, reduce dead water area and improve the utilization rate of sedimentation tank volume.

Settling area: The area where the precipitated particles are separated from the wastewater.

Sludge area: the area where sludge is stored, concentrated and discharged.

Buffer zone: It is the water layer area that separates the precipitation area and the sludge area to ensure that the precipitated particles do not float again due to the agitation of the water flow.

3. The difference between sedimentation tank and sedimentation tank: Sedimentation tank is generally located in the sewage treatment plant before the biochemical structure of sludge water separation facilities. Most of the separated precipitating materials are sand with large particles, large proportion of precipitating materials, high inorganic composition and low water content. Sewage is inevitably mixed with mud and sand in the process of migration, flow and collection. If the sand in the sewage is not settled and separated in advance, it will affect the operation of the subsequent treatment equipment. The most important thing is to wear the pump, block the pipe network, interfere with or even destroy the biochemical treatment process.

Sedimentation tank is generally a structure for sludge and water separation before or after biochemistry, mostly for separating finer particles of sludge. Before the biochemical is called the primary sedimentation tank, the precipitated sludge is called more inorganic, and the sludge moisture content is lower than that of the secondary sedimentation tank. The sedimentation tank located after the biochemical process is generally called the secondary sedimentation tank, which is mostly organic sludge, and the sludge moisture content is higher.

4. Sedimentation tank type: flat flow sedimentation tank, vertical flow sedimentation tank, amplitude flow sedimentation tank, oblique flow sedimentation tank

A. Flat-flow sedimentation tank: simple structure, good precipitation effect, but occupies a large area, there are more problems in sludge discharge, at present, large, medium and small sewage treatment plants are used.

b. Vertical sedimentation tank: covers an area of small, more convenient mud discharge, and easy to manage, but the pool is too deep, difficult to construct, high cost, so it is generally only suitable for small and medium-sized sewage treatment plants.

c. amplitude-flow sedimentation tank: the most suitable for large-scale water treatment plants, with a stereotypical mud discharge machinery, the operation effect is good, but it requires higher construction quality and management level.

d. Inclined flow sedimentation tank: mainly suitable for initial sedimentation tank, widely used in water supply treatment, high precipitation efficiency, short residence time, less land, the disadvantage is easy to breed algae, difficult to discharge mud, easy to block, inconvenient maintenance.

Air flotation tank

Air flotation method: Air is passed into the sewage to produce tiny bubbles as carriers, so that pollutants such as emulsified oil and tiny suspended matter in the sewage adhere to the bubbles. By using the buoyancy of bubbles to float to the surface of the water, the purpose of separating impurities and purifying sewage is achieved by collecting the foam or scum on the water surface.

Hydrolytic acidification tank

The purpose is mainly to convert the insoluble organic matter in the original wastewater into dissolved organic matter, especially the industrial wastewater, mainly to convert the difficult biodegradable organic matter into the easy biodegradable organic matter, improve the biodegradability of the wastewater, in order to facilitate the subsequent aerobic treatment.

The degradation of organic matter by activated sludge is mainly carried out in the aeration stage, which can be divided into two stages, adsorption stage and stabilization stage. In the adsorption stage, the organic matter in the sewage is mainly transferred to the activated sludge, which is because the activated sludge has a huge specific surface area, and the surface contains polysaccharide sticky substances caused by. In the stable stage, the organic matter on the transferred activated sludge is mainly used by microorganisms. When the organic matter in the sewage is in a suspended state and colloidal state, the adsorption stage is very short, generally about 15-45min, and the stability stage is longer.

SBR method:

SBR method: called sequence batch activated sludge method is a modification of continuous activated sludge method, and its reaction mechanism and pollutant removal mechanism are basically the same as the traditional activated sludge method, only the operation is different.

Classic SBR reactor disadvantages:

1. The application of a single SBR reactor requires a large regulating pool;

2. For multiple SBR reactors, water inlet and drainage valves automatically switch frequently;

3. It cannot solve the treatment requirements of continuous inlet and discharge of large sewage treatment projects;