is in the range of 4 to 7 and above 9, whereas for ferric chloride, effective pH range is
3.5 to 6.5 and above 8.5 (Garg 2013).
13.7.4 Water Temperature
Higher temperature may lead to more collision of colloidal particle resulting in
overcoming of electrostatic repulsive force by van der Waals force of attraction.
This attractive force makes the colloidal particles to aggregate and settle down more
quickly.
13.7.5 Cost and Availability
For the dye industry, treatment of effluent is a challenging task if stringent rules and
cost of treatment have been considered in combination. Any coagulant can be used
commercially only if that is readily available at low cost and efficient for target
pollutants (Verma et al. 2011).
13.7.6 Dewatering Characteristics of the Solids that Are
Produced
The flocs formed and settled down to form solid sludge. The treatment of sludge also
requires huge economy and energy. So the dewatering capacity of sludge also
impacts the use of any efficient coagulant.
The selection of coagulants and coagulant aids plays an important role in curbing
the dye pollution load. Sometimes the use of these coagulants gets affected by
various factors that govern their use in treating dyes and also makes them more
specific for the particular pollutant (Fig. 13.5).
All these aforementioned parameters highly influence the selection of the coagulant for commencement of coagulation/flocculation. Along with the types of
coagulants, other factors also affect the coagulation/flocculation process that are
explained in detail by the following section.
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3.5 to 6.5 and above 8.5 (Garg 2013).
13.7.4 Water Temperature
Higher temperature may lead to more collision of colloidal particle resulting in
overcoming of electrostatic repulsive force by van der Waals force of attraction.
This attractive force makes the colloidal particles to aggregate and settle down more
quickly.
13.7.5 Cost and Availability
For the dye industry, treatment of effluent is a challenging task if stringent rules and
cost of treatment have been considered in combination. Any coagulant can be used
commercially only if that is readily available at low cost and efficient for target
pollutants (Verma et al. 2011).
13.7.6 Dewatering Characteristics of the Solids that Are
Produced
The flocs formed and settled down to form solid sludge. The treatment of sludge also
requires huge economy and energy. So the dewatering capacity of sludge also
impacts the use of any efficient coagulant.
The selection of coagulants and coagulant aids plays an important role in curbing
the dye pollution load. Sometimes the use of these coagulants gets affected by
various factors that govern their use in treating dyes and also makes them more
specific for the particular pollutant (Fig. 13.5).
All these aforementioned parameters highly influence the selection of the coagulant for commencement of coagulation/flocculation. Along with the types of
coagulants, other factors also affect the coagulation/flocculation process that are
explained in detail by the following section.
320
S. Sonal and B. K. Mishra