Flow Equalization Tank
The main function of the equalization tank is to act as a buffer: to collect the raw incoming sewage that comes at widely fluctuating rates and pass it on to the rest of the sewage treatment plant at a steady flow rate.
- The tank is rectangular in shape to provide placement of air diffusers for full floor coverage.
- The diffusers are retrievable. Sets of diffusers may be lifted out and cleaned for routine maintenance.
- Aeration is carried out using course bubble diffusers
- The inlet pipe carries filtered sewage from the Bar Screen Chamber.
- The sewage is collected in the tank. The level fluctuates throughout the day, because while the incoming rate fluctuates widely, the outgoing rate is constant.
- The raw sewage lift pumps move the sewage to the aeration tank.
- The delivery pipe takes the sewage to the aeration tank.
- The coarse bubble diffusers are short length of tubes that have holes at regular spacing. They release large bubbles in the tank to lightly aerate the sewage, and also to agitate the mix continuously. The figure shows an array of eight diffusers, strapped to cement blocks so that the assembly remains firmly anchored in one place. Diffusers can also be used in separate pairs or even individually.
- Compressed air comes though this air supply pipeline. This may be a rigid pipe or a flexible hose. The figure shows a single array of 8 diffusers. However, it is more convenient to use separate pairs of diffusers with their own air pipe (flexible hose).