Environmental Engineering Reference
In-Depth Information
used in textile industries (Amoozegar et al.
2011
). Textile process consists of
several steps. Dying and scouring steps are the main sources of color in wastewaters
and ef
uents (Dos Santos et al.
2007
).
3 Textile Wastewater Efuents Properties
Industrial ef
uents treatment approaches should be designed in a way to meet the
goals of protecting the assimilative capacity of surface waters; saving different
kinds of life; preserving or restoring the aesthetic and recreational value of surface
waters and protecting human beings from adverse effects of deteriorating water
quality conditions. Selection among different wastewater treatment facilities is
based on the knowledge of different factors, like physical, chemical and biological
characteristics of wastewater, the quality of water reservoirs (rivers, ponds, streams,
etc.) must be maintained in which the wastewater is to be released or the quality that
the wastewater should meet environmental standards after treatment for reuse for
various purposes. The main physical characteristics of industrial wastewaters are
their solid content, color, odour and temperature. However, chemical characteristics
of wastewaters are divided into two main classes: organic and inorganic charac-
teristics. Inorganic chemicals, that enable us to choose the proper method for the
wastewater treatment, are varying according to the wastewater origin. In organic
factors include free ammonia, organic nitrogen, nitrites, nitrates, organic and
inorganic phosphorous, chloride, sulphate, heavy metals, hydrogen sulphide, oxy-
gen, methane and carbon dioxide. In order to assess the organic content of
wastewaters, biological oxygen demand (BOD), chemical oxygen demand (COD),
total organic compound (TOC) and volatile organic compounds (VOC) need to be
determined carefully, as they have a great impact on choosing proper biological
treatment technology. Typical characteristics of textile industry wastewater are
presented in Table
2
(Al-Kdasi et al.
2004
).
The textile industries wastewaters are a complex mixture of salts, acids, heavy
metals, organochlorine-based pesticides, pigments, dyes etc. Dyes and dyestuff are
of primary importance in textile manufacturing. In discriminate release of colored
Table 2 Composite textile
industry wastewater
characteristics
Parameters
Values
pH
7.0
9.0
-
Biochemical oxygen demand (mg l
−
1
)
80
-
6,000
Chemical oxygen demand (mg l
−
1
)
150
12,000
-
Total suspended solids (mg l
−
1
)
15
8,000
-
Total dissolved solids (mg l
−
1
)
2,900
-
3,100
Chloride (mg l
−
1
)
1,000
-
1,600
Total kjeldahl nitrogen (mg l
−
1
)
70
80
-
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