Layout form and existing problems of water collecting tank in daily life 

   Analysis and summary of problems in the design of collecting tank. The secondary sedimentation tank is an important sewage treatment unit in the biological treatment process of urban sewage. Its main role is to promote the separation of sludge and water, solid and liquid, and improve the concentration of returned sludge and excess sludge. There are many influencing factors in the design and operation of secondary sedimentation tank, such as the type of secondary sedimentation tank, water inflow form, surface area, tank depth, the load on the overflow weir at the collecting tank, the temperature of sewage, and the sedimentation performance of sludge itself.

In terms of tank type and structure, there are three types of secondary sedimentation tanks: radial flow type, horizontal flow type and vertical flow type. The tank types are round and square, and the circular radial flow type secondary sedimentation tank is the most common form of sewage biological treatment at present. The layout form and existing problems of the catch basin The catch basin of the secondary sedimentation tank is the last link and process of mud water and solid-liquid separation in the sewage sedimentation process. In the actual engineering design, there are three common layout forms: built-in double side weir, built-in single side weir, and external single side weir. The built-in single side weir and the external single side weir are both single side weirs.

The design weir load is basically the same. From the perspective of structure and hydraulic conditions, there is no obvious difference between the two. The built-in double weir type catch basin is widely used due to the small load on the weir and good effluent quality. However, in the recent engineering design and application, it is found that there are two main phenomena in the inlet sump of the bilateral weirs: when the water quality at both sides of the sump is tested, the water quality at the inner side is better than that at the outer side. Due to the excessive opening of the balance hole in the collecting flume, the uniform water collection effect of the triangular weir will be reduced