Pressurized Ozonation

Abstract

Increasing populations and improving standards of living are placing increasing burdens on water resources. The preservation of our limited natural water supplies and, in the not too distant future, the necessity for direct recycling of water in some parts of the country will demand improved technology for the removal of contaminants from wastewater. The contaminants in wastewater are many and continually varying, and they are not well-characterized according to chemical species. Commonly the level of organic contamination is expressed by biochemical oxygen demand (BOD), chemical oxygen demand (COD), or total organic carbon (TOC). Ozone and oxygen are powerful oxidants, which can oxidize many contaminants in wastewater and sludge biosolids. Ozone is more powerful than oxygen, but it is an unstable material, which must be generated at the point of use. Ozone has been used for disinfecting drinking water in European countries for many years. It has also been used for treating some special industrial wastes, notably for removing cyanides and phenols. Since 1980, ozone started to be used for wastewater, industrial wastes, and sludge treatment on a large scale (1)--(6). Oxidative purification and disinfection with ozone as a tertiary wastewater treatment or sludge treatment has a number of inherent advantages which are as follows:a.Reduction in BOD and COD.b.Reduction of odor, color, turbidity, and surfactants.c.Pathogenic organisms are destroyed.d.The treatment products are beneficial.e.The effluent water has a high dissolved oxygen (DO) concentration.