Study of rejuvenation of industrial effluent remediation by innovative cavitational reactors

Abstract

Wastewater discharge from industrial units containing complex and refractory chemicals is a large problem for conventional treatment plants in the whole world. The release of these wastewater containing dyes and other toxic components in the natural environment is not only hazardous to aquatic life but also carcinogenic and mutagenic to humans. Thus, it is important to build up a novel approach based on intensified techniques leading to complete removal of these toxic chemicals from the effluents without generating the secondary waste. Several methods are available to treat wastewater containing complex chemicals such as coagulation, flocculation, conventional methods, adsorption etc. These methods are unable to thoroughly degrade such chemicals present in the effluent. Alternative techniques which involve the chemical transformation of organic pollutants and oxidizes such pollutants and end up with the formation of CO2, H2O etc. are known as Advance Oxidation Processes (AOP). Various advance oxidation processes have been explored by researchers for treatment of organic pollutants over the years such as cavitation, Fenton oxidation, ozonation, photocatalysis etc. Also, from studies of the last few decades, cavitation is considered as promising technology for the complete removal of pollutants containing wastewater. Cavitation is such a unique technique extensively studied for the treatment of wastewater containing dyes and other complex chemicals. It has the ability of generating highly reactive free radicals, which are the key factors for degradation of dyes. In the present work, effluents containing formic acid, phenol and Rhodamine 6G considered as a model pollutant for the treatment. These effluents are hazardous and complex structured pollutants and are considered as a priority toxic pollutant by US Environmental Protection Agency (EPA). EPA has set maximum exposure range of 1 to 20 ppb (parts per billion). In the present work, AOPs is achieved by using two cavitational reactors such as hydrodynamic cavitation and bubble cavity induced photoreactor. However, author developed and filed an Indian patent on the bubble cavity induced photoreactor. It has been observed during previous studies, beneficial effects of bubble cavity induced oxidation using combination of UV and glass balls for removal of Methyl Violet 2B dye. A careful analysis of the literature indicates that there have been no studies related to the usage of bubble cavity induced photoreactor for the effluent treatment processes from various industries. (AU)