Aluminum Chloro Hydrate

Definition of ACH

ACH or Aluminum Chloro Hydrate indicates how long the water stays in the clarification or sedimentation unit before exiting to the next stage. It describes the time it takes for the water to settle, at which point the suspended solids will drop to the bottom of the tank (become sludge).

Calculation Formula

Description:

• V = Volume of clarification tank (m³)

• Q = Water flow rate (m³/hour)

• ACH = Hydraulic residence time (hour)

Example:
If the tank volume is 200 m³ and the flow rate is 50 m³/hr:

This means that the water is in the tank for an average of 4 hours before it comes out.

Function in Water Treatment

ACH values are used for:

• Determining settling efficiency in sedimentation or clarification units.

• Regulate the design and operation of the water treatment system, so that the settling process is optimized.

• Avoiding short-circuiting (water flowing too fast), which prevents particles from settling.

General values

For drinking water or wastewater treatment units:

• • • Raw water clarification: 2-4 hours

    • Clarification of domestic sewage: 1.5-3 hours

    • Heavy industrial clarification: can be 4-8 hours depending on the type of solids