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The acid capacity plays a decisive role in biological wastewater treatment. A minimum acid capacity of 1.5 mmol/l, or better 2 mmol/l, in the effluent of the biological treatment plant is recommended, since the biological processes are otherwise severely disrupted by excessively low pH values (< 7.0).
According to the equation: CaCO3 + CO2 + H2O → Ca(HCO3)2 an acid capacity of 2 mmol/l can be produced by adding 1 mmol/l chalk (100 g/m3).
Compared to other chemicals, the natural product chalk has the following advantages:
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Cost-efficiency
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High reactivity and rapid dissolution
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Simple handling
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No risk of exceeding pH values
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No encrustation in pipelines
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No sedimentation
In addition to stabilising the pH value, chalk has positive effects on the entire wastewater treatment process, such as:
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Sludge weighting
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Improved dewatering properties
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Support of biological P elimination
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Buffer system
The Optical 20 grade is a suitable type from our product range.
Optical – fine chalk from the Plant Söhlde
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