Ozonation and ozone / UV process for industrial wastewater treatment: comparison between two types of wastewater

Abstract

This study investigated the degradation of organic and inorganic matters of wastewater by conventional ozonation and ozone/UV AOPs. The experiments performed with two types of wastewater (synthetic and industrial) having the same chemical oxygen demand COD, varying solution pH and employing UV clearly showed that oxidation during ozonation process was dominated by OH reactions. Conventional ozonation with 2 g/hr maximum ozone dose led to 56% COD removal efficiency in synthetic wastewater, while 52% was estimated from industrial wastewater, both having the same initial COD value of almost 50 ppm and contact time of 80 min. In meanwhile, using UV improved the utilization efficiency of oxidation by reducing the OH scavenging contribution of oxidants, 62% and 70% were the efficiencies of industrial and synthetic respectively in ozone/UV applications. Therefore, combined ozone/AOPs shows better removal efficiency of toxic contaminants than using ozone alone.