Physico-chemical Process
The ammoniacal effluents are removed with the help of physico-chemical processes
(air stripping, steam stripping and ion exchange). These effluents are not hydrocarbon based. The suspended solids and oil-grease bearing effluents are removed from
fertilizer wastewater by physical process. Generally, the suspended solids are settled
down by gravity, but when particle size is small enough, then mechanical clarifiers
with proper dosing of coagulants or poly-electrolytes is used for quick settling. The
sludge is then discharged from the bottom of the clarifier by either dewatering or
mechanically.
The oil-grease based effluents are discharged from fertilizer wastewater in
non-emulsified form. The lighter oil-grease floats over the water in an oil-water
separator and then easily separated by using skimmer. This type of effluent may be
regularly skimmed out mechanically. Usually, by this process, 50 mg/L of oil-grease
effluents are removed. But, if high degree of efficiency is required, then the effluents
pass through the activated carbon or porous coke bed as in refinery’s activated
carbon adsorption process. Then oil-grease concentration in effluents as low as
2–10 mg/L can be achieved (Sengupta 2019; Elela and Elkamah 1995).
Biological Process
The oil-bearing or hydrocarbon-based wastes are treated by biological processes.
The biological treatment of wastewater in fertilizer industry is almost similar to that
of a petroleum refinery.
8.4.7 Wastewater Treatment in Textile Industry
The textile wastewater contains colour pigments, dying materials, organic compounds, etc. The textile effluents are much polluted, since they contain reactive
dyes which are not easily treated by biological processes. The reactive dyes and
colour organic matter are very harmful for the growth of aquatic organisms and
imbalance the environment. Hence, the wastewater from textile industry should be
treated by chemical, biological, physical and hybrid treatment processes before
discharge. It can also be treated using membrane technology which is similar to
refinery wastewater membrane technology such as microfiltration, ultrafiltration,
nanofiltration and reverse osmosis processes (Jain et al. 2016; Vineta et al. 2014).
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The ammoniacal effluents are removed with the help of physico-chemical processes
(air stripping, steam stripping and ion exchange). These effluents are not hydrocarbon based. The suspended solids and oil-grease bearing effluents are removed from
fertilizer wastewater by physical process. Generally, the suspended solids are settled
down by gravity, but when particle size is small enough, then mechanical clarifiers
with proper dosing of coagulants or poly-electrolytes is used for quick settling. The
sludge is then discharged from the bottom of the clarifier by either dewatering or
mechanically.
The oil-grease based effluents are discharged from fertilizer wastewater in
non-emulsified form. The lighter oil-grease floats over the water in an oil-water
separator and then easily separated by using skimmer. This type of effluent may be
regularly skimmed out mechanically. Usually, by this process, 50 mg/L of oil-grease
effluents are removed. But, if high degree of efficiency is required, then the effluents
pass through the activated carbon or porous coke bed as in refinery’s activated
carbon adsorption process. Then oil-grease concentration in effluents as low as
2–10 mg/L can be achieved (Sengupta 2019; Elela and Elkamah 1995).
Biological Process
The oil-bearing or hydrocarbon-based wastes are treated by biological processes.
The biological treatment of wastewater in fertilizer industry is almost similar to that
of a petroleum refinery.
8.4.7 Wastewater Treatment in Textile Industry
The textile wastewater contains colour pigments, dying materials, organic compounds, etc. The textile effluents are much polluted, since they contain reactive
dyes which are not easily treated by biological processes. The reactive dyes and
colour organic matter are very harmful for the growth of aquatic organisms and
imbalance the environment. Hence, the wastewater from textile industry should be
treated by chemical, biological, physical and hybrid treatment processes before
discharge. It can also be treated using membrane technology which is similar to
refinery wastewater membrane technology such as microfiltration, ultrafiltration,
nanofiltration and reverse osmosis processes (Jain et al. 2016; Vineta et al. 2014).
268
M. Samanta and D. Mitra