Equalization Tank

Equalization Tank also called Collection Tank sometimes

Manufacturers Sewage Treatment Plants Effluent Treatment Plants ETP STP Lamella Clarifier MBBR Diffusers Fine bubble Media 

Equalization Tank / Collection Tank

Equalization Tank in any Treatment Plant serves the purpose of maintaining desired flow rate as well as for making mixture homogeneous. It is evident that effluent of any industry is heterogeneous in nature , to bring the best out of any wastewater treatment plant homogeneous mixture is must

Homogeneous mixture in Equalization Tank is done via the actions of coarse bubble diffusers , oxygen transfer efficiency of a coarse bubble diffuser is 10%-20% and are capable of delivering 6 - 12 m3 / hour air , typical diameter of coarse bubble diffuser is 150 mm , coarse bubble diffuser is shown below

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Below mentioned criteria or precautions must be followed for designing any Equalization Tank

Easy accessible

The tank must be easy accessible for periodic cleaning with safety and comfort for a gang of cleaners to carry out the task
 

Safe Entry

The operator has to access the inside of the tank for periodic cleaning and to maintain the diffusers. The tank has relatively low oxygen level and the raw wastewater emits hazardous gases and strong odor. So the operator must be provided with safety Equipments such as mask, gloves, full body harness, gum boots . The following features must be present, at minimum: Ventilation to dispel the gases/odor Good lighting that reaches inside the tank Platform that allows easy reach inside the tank

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Aeration and Mixing

Diffusers in sufficient number to cover the entire floor Uniform placement of diffusers The aeration is uniform across the surface. To prevent the solids from settling in dead zones (which in turn avoids the necessity to clean the tank frequently )
 

Why to use coarse bubble diffusers ?

Unlike the fine bubble diffusers, the coarse bubble diffusers are not affected by fluctuating water level.

Floor slope towards suction pit for pumps

For complete evacuation of contents by pump. Floor slope is given so that during tank cleaning, all the water is collected in the suction pit of the pumps and the equalization tank is evacuated by pumps alone, with minimum manual cleaning required.
 

Openness of the Tank

To prevent accumulation of gases , easy access to diffusers for maintenance purposes, and safe and secure entry for periodic cleaning