Disinfection

Disinfection refers to the selective destruction of disease-causing micro-organisms. This procedure is of significance within wastewater treatment owing to the nature of wastewater that harbours a number of human centeric organisms that are associated with various waterborne diseases. Generally used means of disinfection involved the following:

(a)        Physical agents like as heat and light.

(b)       Mechanical means like as screening, sedimentation, filtration, and so on.

(c)        Radiation, commonly gamma rays.

(d)       Chemical agents involving chlorine and its compounds, iodine, bromine, ozone, phenol and phenolic compounds, alcohols, heavy metals, dyes, soaps and synthetic detergents, hydrogen peroxide quaternary ammonium compounds,  and several alkalis and acids.

The most general chemical disinfectants are the oxidizing chemicals, and of these, chlorine is the most hugely used.

Disinfectants act by one or more of a number of mechanisms, including damaging the altering cell permeability, cell wall, the colloidal nature of the protoplasm and inhibiting enzyme activity. In applying disinfecting agents, various factors requires to be considered, that is contact time, concentration and kinds of chemical agent, intensity and nature of physical agent, number of organisms, temperature, and nature of suspending liquid.