Treatment of Textile Waste Water Using Low-Cost …
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Table 1 Nature of textile waste water [4, 10, 21]
Process
Possible
pollutants
Waste water characteristics
Volume
BOD
COD
Alkalinity Others
Sizing
Starch,
glucose, PVA,
resins, fats and
waxes
Small
High
Medium
Metals,
cleaning
waste, yarn
waste
Desizing
Starch, CMC,
PVA, resins,
fats and
waxes,
pectins,
ammonia
Very small
High
(30–50%
of total)
High
Biocides,
anti-static
compounds
Scouring
Caustic soda,
waxes, soda
ash, sodium
silicate and
fragments of
cloth
Very small
High
(30% of
total)
High
Dark colour
Bleaching
Hypochlorite,
chlorine,
caustic soda,
hydrogen
peroxide,
acids
Small
Low
(5% of
total)
High
High
suspended
solids
Mercerizing Sodium
hydroxide,
cotton wax
Small
Low
(less than
1% of
total)
Low
High
High
dissolved
solids
Dyeing
Dye stuff,
mordant,
formaldehyde,
acetic acid,
detergent,
reducing
agents and
wetting agents
Large
Fairly
high
(6% of
total)
High
High
Strong
colour,
highly toxic,
high pH,
high
dissolved
solids (TDS)
Printing
Dye, starch,
gum oil, urea,
solvents,
binders,
thickeners,
mordants,
cross-linking
agents, acids
and metallic
salts
Very small
Fairly
high
High
Oily
appearances,
high toxicity,
strong
colour, high
pH, high
TDS
(continued)