CO₂-neutralisation

Neutralisation of alkaline waste waters by means of CO₂ is possible in breweries, dairies, etc. In contrast to when strong acids are used, the neutralisation with CO₂ goes much more gradual, in terms of the process is better.

Application scope

pH-neutralisation of alkaline waste water by CO₂ has many application areas. The process is amongst other used:

• in breweries for the cleaning of waste water that was used in the rinsing of bottles
• in dairies
• in textile dying to neutralise the strong NaOH solution that is used with the dying
• in concrete panels

Waste water may only be discharged when the pH-value is between pH 6 and pH 8.5.

Requirements

• CO₂-sphere or tank
• Evaporator
• pipe decompressor
• pH-metres
• CO₂-injection system with an injection valve controlled by a pH metre

IJsfabriek Strombeek offers in addition to CO₂ and the other equipment also two possible injection systems:

• on the bottom of the waste water tank
• in the line after the pump. To get a good absorption of CO₂ a pipe length of minimum 50 meters is needed.

As one of the largest producers of CO₂ IJsfabriek Strombeek is your ideal partner for a CO₂-installation to measure. Our team of engineers with all their experience and expertise are ready for you to find the best solution.

The table below shows the number of kg of CO₂ per m³ waste water that is needed to obtain a pH of 8.5 in function of the initial pH of the waste water:

pH	kg CO2
10.0	0.004
11.0	0.044
12.0	0.44
13.0	4.40
14.0	44.0

Advantages

• The risk of a too acidic waste water is much smaller than with neutralisation with strong acids.
• The residue product (carbonates) is less harmful than the chlorides, sulphates or nitrates of classical strong acids.
• CO₂ has less chance of injury for the user than strong acids.
• CO₂ is a cost-effective alternative.

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