Environmental Engineering Reference
In-Depth Information
carbonate minerals such as gypsum, anhydrite, dolomite and magnesite show
undersaturation, whereas about 50 % of calcite and aragonite minerals show over-
saturation in the groundwater samples of the study area. Water samples which are
oversaturatedwiththesecarbonatemineralsindicatedthattheexcessinputofCa
2+
and Mg
2+
ionsaremainlyfromcarbonateweatheringprocesses.Oversaturationof
groundwater with carbonate minerals in some of the samples shows that these min-
erals calcite, dolomite and aragonite are already precipitated in the past and are not
contributingmuchofCa
2+
and Mg
2+
in the groundwater.
Classification of Groundwater for Domestic Use
The water used for drinking should be free from colour, turbidity and microorgan-
isms (Karanth
1989
). To ascertain the suitability of groundwater for drinking and
public health use, hydrochemical parameters of the study area are compared
(Table
2
)withtheguidelinesrecommendedbyWorldHealthOrganization(WHO
1993
). From Table
1
, it is evident that one groundwater sample for sodium ion, two
samples for fluoride ion in pre- and post-monsoon season, and six groundwater
samples for iron in pre-monsoon season are exceeding the permissible limits set by
WHO.According toWorld Health Organization, aTDS of up to 500 mg/l is the
optimum value, whereas a TDS of 1,500 mg/l is the maximum permissible concen-
tration (Table
1
) and all the groundwater samples of the study area are within the
permissible limits. Water can be classified (Davis and De Wiest
1966
) on the basis
of total dissolved solids. It is observed that 56 % and 43 % in pre-monsoon and
66 % and 33 % in post-monsoon samples are within desirable limits for drinking
and permissible limits for drinking respectively and all are useful for irrigation
(Table
2
).AspertheFreezeandCherry(
1979
) classification 89 %, 11 % in pre-
monsoon and 100 % in post-monsoon season are within fresh water type and brack-
ish water type, respectively. The groundwater classification based on total hardness
(TH)(SawyerandMcCarty
1967
) shows that 11 %, 78 %, 11 % in pre-monsoon fall
in the moderately hard, hard and very hard water category, and 100 % in post-
monsoon fall in the hard water category (Table
2
).AspertheWHOstandards,TH
for all samples is within the maximum permissible limit (500 mg/l) of groundwater
(Table
1
). Water with TH above 75 mg/l cannot be used for domestic purposes
because it coagulates soap lather.
Classification of Groundwater for Irrigation Use
The development and maintenance of successful irrigation projects involve not only
the supply of irrigation water to the land but also the control of salt and alkali in the
soil (Haritash et al.
2008
). The suitability of groundwater for agricultural uses is
determined by parameters such as chloride (Cl
−
), electrical conductivity (EC),
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