Learn about the comparison between lime-soda and zeolite process for water softening.
Comparison # Lime-Soda Process:
1. Size of Plant:
Bulky and large.
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2. Supervision Required:
Skilled supervision is required for successful working.
3. Sludge Problem if any:
Large quantity of sludge is formed which needs to be disposed off by some suitable method.
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4. Post Treatment if Needed:
Recarbonation is needed which if not done will cause incrustation in pipes of the distribution system.
5. Results Obtained:
This can produce water of hardness not less than 50 mg/l. Therefore it is useful for public water supplies only.
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6. Removal of Iron and Manganese:
Can remove iron and manganese from water to some extent.
7. Bactericidal:
There is likelihood of killing of bacteria in this process. This occurs when causticity caused by calcium hydroxide or sodium hydroxide of 20 to 50 p.p.m is retained in the treated water for a period of about 4 to 5 hours.
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8. pH value of Treated Water:
pH value of water treated by this process is increased which results in decrease in corrosion of the distribution system.
9. Care Needed in Handling Materials:
Careful handling is required because the materials, i.e., lime and soda are corrosive.
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10. Economy:
Process is economical and it can be easily combined with usual water treatment plant.
11. Hardness which can be Treated:
Excessively hard waters, particularly those which are high in magnesium hardness can be treated.
12. Allowable Turbidities in Raw Water:
Highly turbid and acidic waters can be treated.
Comparison # Zeolite Process:
1. Size of Plant:
Compact and small.
2. Supervision Required:
Automatic and easy to operate and no skilled supervision required.
3. Sludge Problem if any:
No sludge is formed and hence there is no problem of its disposal.
4. Post Treatment if Needed:
No such post treatment is required.
5. Results Obtained:
Water of zero hardness can be obtained. Therefore useful for industrial supplies also.
6. Removal of Iron and Manganese:
Not suitable for water containing iron and manganese, because iron zeolite and manganese zeolite may be formed which cannot be reconverted into sodium zeolite.
7. Bactericidal:
Bactericidal effect does not exist in this process.
8. pH value of Treated Water:
pH value of water treated by this process is not affected.
9. Care Needed in Handling Materials:
Salt solution is required to be handled which does not require much care.
10. Economy:
Process is relatively costly.
11. Hardness which can be treated:
Raw water with hardness greater than 800 mg/I cannot be easily and economically treated.
12. Allowable Turbidities in Raw Water:
Highly turbid waters are difficult to be treated because the suspended impurities get deposited around zeolite particles and hence cause obstruction to the working of zeolite.