Unit : 7

Design criteria and design of Chlorine Contact Tank : 

A chlorine contact tank, also known as a chlorine residual contact chamber, is a water treatment component that is used to disinfect water by adding chlorine to it. The design criteria for a chlorine contact tank include:

Sufficient Contact Time: The chlorine contact tank should provide enough contact time between the chlorine and the water to ensure that the water is properly disinfected.

Adequate Mixing: The chlorine contact tank should be designed to ensure that the chlorine is thoroughly mixed with the water to ensure a consistent level of disinfection.

Durability: The chlorine contact tank should be made of materials that are resistant to corrosion and abrasion, and can withstand the harsh conditions of water treatment.

Safety: The chlorine contact tank should be designed with safety features such as overpressure and over-chlorination protection to prevent accidents.

A typical design of a chlorine contact tank includes the following components:

Tank or vessel: The tank is usually made of concrete or fiberglass and is designed to hold the water to be disinfected.

Chlorine feed system: This system is used to add chlorine to the water in the contact tank. The chlorine is typically added as a liquid or a gas.

Mixing system: This system is used to mix the chlorine with the water to ensure that it is evenly distributed throughout the tank. This could be mechanical mixers, diffusers or other types of mixers.

Control valves: These valves are used to control the flow rate of water and chlorine entering and leaving the contact tank.

Effluent Trough: The effluent trough is used to collect the disinfected water as it exits the contact tank.

Control Panel: The control panel is used to control and monitor the operation of the contact tank, including the flow rate, chlorine dosage, and contact time.