Review Paper FORMATION OF HYDROXYL RADICALS FOR WASTE WATER TREATMENT BY PHOTO-CATALYTIC OXIDATION PROCESS

Organic pollution is the term used when large quantities of organic compounds are found in waste water. It originates from domestic sewage, urban run-off; industrial effluents and agriculture wastewater. Water shortage and water quality are the main issues in the global water crisis. As the population increases, there is ever growing demand on water resources. Wastewater with organic pollutants contains large quantities of suspended solids which reduce the light available to photosynthetic organisms and, on settling out, alter the characteristics of the river bed, rendering it an unsuitable habitat for many invertebrates. Purification of water is essential for availability of good quality water. Advance oxidation process (Photo-catalytic oxidation process) is a method for degradation of organic compounds in waste water through a semiconductor catalyst i.e. TiO2 with UV light. This paper discusses the organic and inorganic pollutants in waste water and there removal via photo-catalytic oxidation process. In this paper, the mechanisms of photo-catalytic oxidation process are discussed to radical formation i.e. OH*. These radicals (i.e. OH*) are capable to destroy the organic pollutants in waste water. This paper also discusses the several other conventional methods for purification of water.