Abstract

In the present work, degradation of effluent from distillery wastewater has been carried out using hydrodynamic cavitation, one of the novel upcoming Advance Oxidation Processes for the treatment of industrial wastewater. The multiple hole orifice plates and circular venturi used as cavitating devices. The phenomena of cavitation which is associated with the formation, growth and subsequent collapse of microbubbles with small time of interval as milliseconds and releasing of a large amount of energy at multiple locations in the reactor. The cavitation occurs at various locations in the reactor simultaneously and generates very high temperature and pressure like thousands of atmospheric pressure and thousands of 0K temperature. These cavitation phenomena generated by liquid flow pattern hence termed as hydrodynamic cavitation. The highly color compound present in the effluent reduces sunlight penetration in the rivers, lakes or lagoons which result in decrease both photosynthesis activity and dissolved oxygen concentration that affecting the aquatic life. The wastewater used as molasses-based distillery effluent called as spent wash obtained from a local site. This wastewater is first diluted by 2-3 time by tap water before experimentation. The applications of hydrodynamic cavitation for distillery wastewater is to study the effect of inlet fluid pressure for mineralization, the effect of dilution for mineralization, the effect of cavitation for color reduction, the effect of cavitation for biodegradability and effect of temperature using oxidizing agent were studied and optimized the parameter to enhance the Biodegradability Index. The effect of venturi inlet pressure on the reduction of COD and TOC was evaluated at 5 bar and 13 bar inlet pressure. The results indicate that there is no significant increase in percentage reduction of COD and TOC with an increase in the inlet pressure. So, 5 bar pressure can be considered as optimum inlet pressure and can be used for further experimentation. The molasses-based distillery wastewater has to be diluted by 25% and 50 % (V/V) using tap water and treated at an optimum inlet pressure of 5 bars. The reported result indicates that reduction of COD & TOC is marginally higher at 50 % dilution. Hydrodynamic Cavitation also used for reduction of color (indirectly toxicity) of molasses-based distillery wastewater. For undiluted wastewater a maximum color reduction was observed as 34%, and for 25% dilution and 50% dilution of wastewater, the maximum color reduction was observed as 41% and 48% respectively. The Biodegradability Index (BI) can be expressed as a ratio of BOD5: COD. For good biodegradability of any wastewater, a minimum value of BI as 0.3-0.4 is considered to be ideal. The treatment on molasses-based distillery wastewater using ozone as an oxidizing agent. The temperature increases for both the combined application of ozone + cavitation, and cavitation alone, but no changes in temperature were observed with the application of ozone alone.

Description