Paper Details

Waste water treatment is practiced using a number of physical, physico-chemical and biological methods oftreatment. Quality of waste water can be defined by the presence various biodegradable and non-biodegradable pollutants,out of which Chemical Oxygen Demand (COD) has been considered as one of the major pollutants in the industrial effluent.In order to achieve desired level of COD reduction, numbers of conventional processes are available but because of their lowefficiency these processes are nowadays being replaced by advanced oxidation processes (AOPs). Different AOPs such asFenton, electro-Fenton, and electro-oxidation etc. have been observed to give better results in terms of COD reduction but atthe same time they are associated with other operational restrictions such as huge chemical requirement and excessivesludge generation.Hydrodynamic cavitation has emerged as promising technology for COD reduction as it does not require chemicals andsludge generation is also very less in this process. This process results in sudden drop and increase of pressure in a liquid,which creates cavities and bubbles followed by sudden and violent collapse. This process results in generation of shockwaves leading to generation of hydroxyl free radical. This hydroxyl free radical causes the development of localized forceswhich have destructive effects on the solids in dispersions, emulsions and slurries affecting particle size and distributionresulting to reduction in COD.Therefore, through this review paper an attempt will be made to combine hydrodynamic cavitation with one on the AOP sothat on the one hand, overall efficiency of the COD removal can be improved and on the other hand, chemical requirementand sludge generation can be reduced.

Mayuri Parmar, Pratibha Gautam, Priyanka Misrty, Harshit Patel, Karan Solanki, ““HYDRODYNAMIC CAVITATION””, International Journal of Advance Engineering and Research Development (IJAERD), Vol. 4, Issue 7, pp. 660-665, July 2017.