Environmental Engineering Reference
In-Depth Information
Table 3.3 Interpretation of
the pollution based on the
BCWQI method
De nition
Numerical value of the index
Excellent
0
3
-
Good
4
17
-
Suitable
18 - 43
Medium
44 - 59
Poor
60
100
-
classi
cation should be conducted based on the type of the water use. Determining
the speci
cations of the water quality will show how desirable for intended use.
Hence, the water quality classi
cation is the most important step in the management
of water quality. Among the water quality indices, N.S.F. WQI is one of the most
used indices and among the specially used indices (drinking purposes and agri-
cultural), BCWQI is a newer and a more acceptable index. Therefore, application of
the two methods is described.
3.5 Application of NFSWQI Method, a Case Study:
K
ā
r
ū
n River (Iran)
in River basin occupies an area of about 67,000 km 2 , and is situated in the
Khuzestan province in south of Iran. The excessive waste water discharge coupled
with the withdrawal of pure water for domestic uses adds to the pollution in K
ā
ū
The K
r
ā
ū
n
River and has critically endangered aquatic life in the river. Since, it is one of the
main rivers in Iran, water pollution in the K ā r ū in River system can significantly
affect the development of Khuzestan Province and consequently, the economic
development of the country since the province has a high potential for agricultural
and industrial development. Therefore, maintaining the water quality of K
r
ā
r
ū
n
River is of strategic signi
cance. A large amount of used agricultural water returns
to the rivers through drainage and return
flows. However, because of its excursion
through agricultural land, it returns with a high concentration of fertilizers, heavy
metals, suspended and dissolved solids and pesticides. Therefore, it violates the
national ef
uent standards. Agricultural and agro- industrial return
flows, domestic
wastewater of the cities and villages and industrial ef
uents are the main pollution
point sources of the K
n River. The river system supplies the water demands of
16 cities, several villages, thousands of hectares of agricultural lands, and several
hydropower plants. Ever increasing population, resulting in a hike in domestic
water demands as well as industrial demand including but not limited to devel-
opment of agricultural networks,
ā
r
ū
fish hatchery projects, and inter-basin water
transfers, darken the outlook for water quality of the K
n River Karamouz ( 2008 )
Fig. 3.3 indicates the water quality monitoring locations on the river.
In this case study, nine water quality parameters, DO, BOD 5 ,NO 3 -, PO 4 -, Total
Solid (TS), pH, T, Turbidity and fecal coli form, was selected. To obtain the
ā
r
ū
nal
weighting factor, 50 questionnaires were sent to faculty members of some of the
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