Environmental Chemistry and Analysis
Prof. M.S.Subramanian
Indian Institute of Technology Madras
MODULE 1.5
Advanced Waste Water Treatment
Removal Of Suspended Solids
1
Microstraining
2
Coagulation and flocculation
2
Filtration
3
Removal of dissolved solids
3
Ion exchange
4
Reverse osmosis
6
Electrodialysis
7
Removal of nitrogen
8
Phosphate removal (chemical treatment)
9
Phosphate removal (biological treatment)
10
Removal of dissolved organic compounds
10
Adsorption
10
Sludge treatment and disposal
11
Disinfection
13
Environmental Chemistry and Analysis
Prof. M.S.Subramanian
Indian Institute of Technology Madras
MODULE 1.5
Advanced Waste Water Treatment
The effluent from a typical secondary treatment plant still contains
20-40 mg/L BOD which may be objectionable in some streams. Suspended
solids, in addition to contributing to BOD, may settle on the stream bed and
inhibit certain forms of aquatic life. The BOD if discharged into a stream with low
flow, can cause damage to aquatic life by reducing the dissolved oxygen content.
In addition the secondary effluent contains significant amounts of plant nutrients
and dissolved solids. If the waste water is of industrial origin, it may also contain
traces of organic chemicals, heavy metals and other contaminants.
Different methods are used in advanced waste treatment to satisfy any of
the several specific goals, which include the removal of (1) suspended solids (2)
BOD (3) plant nutrients (4) dissolved solids and (5) toxic substances. These
methods may be introduced at any stage of the total treatment process as in the
case of industrial waterways or may be used for complete removal of pollutants
after secondary treatment.
Removal Of Suspended Solids:
This treatment implies the removal of those materials that have been
carried over from a secondary treatment settler. Many m