Being underground, the ground water supply has less chance of being contaminated by atmospheric pollution.
MERITS OF SURFACE SOURCES
Merits of ground water sources
1. Being underground, the ground water supply has less chance of being contaminated by atmospheric pollution.
2. The water quality is good and better than surface source.
3. Prevention of water through evaporation is ensured and thus loss of water is reduced.
4. Ground water supply is available and can even be maintained in deserted areas.
5. The land above ground water source can be used for other purposes and has less environmental impacts.
Demerits of ground water source
1. The water obtained from ground water source is always pressure less. A mump is required to take the water out and is then again pumped for daily use.
2. The transport / transmission of ground water is a problem and an expensive work. The water has to be surfaced or underground conduits are required.
3. Boring and excavation for finding and using ground water is expensive work.
4. The modeling, analysis and calculation of ground water is less reliable and based on the past experience, thus posing high risk of uncertainty.
Demerits of surface source
Chemical Characteristics of water
Acidity or alkalinity is measured by pH. PH measures the concentration of Hydrogen ions in water. Ionization of water is
HOH H+ + OH-
In neutral solutions [OH] = [H] hence pH = 7
If acidity is increased, [H] increases and pH reduces from 7 (because H is log of [H]). The value of pH of water is important in the operations of many water and waste water treatment processes and in the control of corrosion.
The values of pH higher than 7, shows alkalinity. The alkaline species in water can neutralize acids. The major constituents of alkalinity (or causticity) are OH-, CO32- and bicarbonates HCO3 ions. Alkalinity in water is usually caused by bicarbonate ions.
Hardness of water: Definition of hard water
Hardness is the property that makes water to require more soap to produce a foam or lather. Hardness of water is not harmful for human health but can be precipitated by heating so can produce damaging effects in boilers, hot pipes etc by depositing the material and reducing the water storage and carriage capacity.
Absolute soft water on the other hand is not acceptable for humans because it may cause ailments, especially to heart patients. Hardness in water is commonly classified in terms of the amount of CaCO3 (Calcium Carbonate) in it.
Degree of Hardness
Concentration of CaCO3 Degree of hardness
0 – 75 mg / L Soft
75 – 150 mg / L Moderately hard
150 – 300 mg / L Hard
300 up mg / L Very Hard