Mumbai university > Civil > SEM 8 > Industrial Waste Treatment

Marks: 5M

Year: Dec 2015 ,

The various processes for the removal of inorganic solids are:

• Phase separation

• Sedimentation

• Filtration

• Oxidation

• Biochemical oxidation

• Chemical oxidation

• Polishing

Phase separation:

Phase separation transfers impurities into a non-aqueous phase. Phase separation may occur at intermediate points in a treatment sequence to remove solids generated during oxidation or polishing. Grease and oil may be recovered for fuel or saponification. Solids often require dewatering of sludge in a waste water treatment plant. Disposal options for dried solids vary with the type and concentration of impurities removed from water.

Filtration:

Colloidal suspensions of fine solids may be removed by filtration through fine physical barriers distinguished from coarser screens or sieves by the ability to remove particles smaller than the openings through which the water passes. Other types of water filters remove impurities by chemical or biological processes.

Oxidation:

Oxidation reduces the biochemical oxygen demand of waste water, and may reduce the toxicity of some impurities. Secondary treatment converts some impurities to carbon dioxide, water and biosolids. Chemical oxidation is widely used for disinfection.