Dissolved CO2 is transferred from the water to the air, and the pH rises in the process.
There are, however limitations on CO2 removal that cannot be overcome by advanced packing technology. Alkaline water tends to retain CO2, so stripping becomes inefficient at pH >7.
Drinking Water Chemistry
Carbon dioxide in water is a weak acid. It is naturally present in rainwater, and is also formed by decay of vegetation in soils and by respiration of aquatic organisms. When rainwater percolates through the ground it dissolves alkaline minerals such as limestone. The water becomes "hard" and its pH and alkalinity increase as acidic CO2 is converted to calcium bicarbonate and other salts.
When CO2 dissolves in water, some of it forms carbonic acid, part of which dissociates into bicarbonate and carbonate ions.
Unreacted CO2 and H2CO3 are collectively referred to as "free CO2."
Bicarbonate and carbonate ions are called "fixed CO2." The sum of "free" and "fixed" CO2 is the "total CO2." The proportions of these different species depend on the pH of the water.
In very acidic water (pH <5), excess hydrogen ion drives these equilibrium reactions to the left, so essentially all dissolved CO2 is free CO2, and the stripping process design is relatively simple.
Materials of Construction
Materials of construction are based on corrosion-resistant materials including FRP and 316 stainless steel.
Clean TeQ® CO2 Stripper or Degasifiers can be used to treat:
- Bore Water
- Recycled Water
- RO Permeate
- Cost effective
- Small space requirement
- Natural process
- No chemical inputs
- No secondary pollution
- Low operating costs
- Energy efficient
- Modular system
- CIP available