Advanced Wastewater Treatment

Essay on Tertiary or Advanced Wastewater Treatment!

Usually the primary and secondary treatments are sufficient to meet wastewater effluent standards. However, if water produced is required to be of higher wa­ter quality standards (in case the water to be put to some direct reuse) then advanced wastewater treatment is carried out.  A wide variety of methods are used in advanced waste treatment, which in­clude the removal of (a) Suspended solids, (b) BOD, (c) Plant nutrients, (d) Dis­solved solids and (e) toxic substances. These methods may be introduced at any stage of the total treatment process as in the case of industrial wastewaters or may be used for complete removal of pollutants after the secondary treatment.

The wastewater treatment processes are basically concentrating or thickening processes on which the suspended solids are removed as sludge’s. The impuri­ties in the wastewater are concentrated into solid form and are then separated from the bulk liquid. This concentrated form is referred to as sludge. Whereas the dissolved solids are first converted into suspended solids which are subse­quently removed as sludge’s.

In addition, the following measures can be taken to control water pollution:

(1) Thermal Pollution:

For minimizing thermal pollution, hot water should be cooled before release from factories, and, removal of forest canopies and irrigation return flows should be prohibited.

(2) Prohibition:

Besides reserving separate water supplies for livestock, the following prohibition should be enforced to avoid contamination of the main sources of drinking water.

(a) Bathing and washing of clothes in rivers and streams.

 (b) Discharging untreated or treated domestic, commercial and industrial sewage in water bodies.

(3) Judicious Use:

Pesticides (preferably less stable) and fertilizers should be very judiciously used to avoid chemical pollution of water through agricul­tural farm run-offs.

(4) Reuse of Water:

The treated wastewater can be reused for several pur­poses, for instance:

·         Treated water can be reused for recreation purposes like fishing and boating.

·         Treated water can be reused as industrial water supply.

·         Reclaimed wastewater can be used for irrigation or municipal purposes.

·         Treated water can be reused for cooling processes in thermal plants.

·         In areas of acute water scarcity, wastewater treated to the highest stand­ards can be reused as potable water (provided there is public accept­ance for wastewater use).