how the process of neutralisation is effective in changing some of the quality of water
Answers
Answer:
neutralising carbonic attack
physical removal of CO2
Potential treatments include:
cascade: ΔH = 1 to 2 m; residual = 10-15 mg CO2·L–1;
sprayed: ΔH = 2 to 5 m; residual = 5-10 mg CO2·L–1;
aeration through diffusion, «medium-size» bubbles: G/L (air flow rate/water flow rate) = 1 to 2; residual = 10-15 mg CO2·L–1;
forced ventilation in a packing column (see eliminating CO2 in chapter 16): G/L = 10 to 100; residual < 5 mg CO2·L–1;
fine layer stripping: G/L = 500 to 1 000; residual < 2 mg CO2·L–1;
the target residual content is the content that will achieve an equilibrium between the M-alk. and CaH in the water.
neutralisation using the chemical method
In most cases this is carried out as an injection of lime, sodium hydroxide or sodium carbonate; please refer to the section neutralisation – remineralisation for details of the reactions involved. Complex systems may require several injections at various stages of the treatment. In plants that have total clarification, with settling tanks (or flotation units) and filters, lime is mainly used and injected at a minimum of two points :
for flocculation pH adjustment (NB in this case, due to the Ca2+ ions, flocculation will be better than when NaOH or Na2CO3 are used); at this stage, lime slurry may be suitable;
for final pH adjustment to the pHs value; one then needs to use a saturator that delivers clear lime water while screening out lime impurities ; sodium hydroxide can be used as an alternative at this point.
Aggressive CO2 can also be neutralised by filtration through a CaCO3 based granular neutralising product, according to the same reaction and implementing the same technology as for remineralisation using this process.
remineralisation
remineralisation using CO2 + lime
The following reaction applies :
Formula: Remineralisation using CO2 + lime
Using this equation, one can calculate that, in order to increase mineralisation (M-alk. and CaH) by 1°F, 8.8 mg · L–1 of CO2 and 7.4 mg · L–1 of pure hydrated lime (or 5.6 mg · L–1 of pure quicklime) have to be injected into the water.
CO2
Industrially, CO2 is supplied in cylinders under a very high pressure and more generally in cooled “low pressure” containers.
In some industrial type installations, CO2 can be obtained by burning gas (submerged burners); however, the impurities generated by incomplete combustion and/or the original fuel, means that it cannot be used for drinking water production.
When used in sea water processing, CO2 obtained by distilling sea water can be recycled and used to remineralise water intended for human consumption (e.g. Alba/Barhein, 43,000 m3·d–1, see figure 43).
Explanation:
please mark me as brainliest