Treatment of fish processing industry wastewater using hydrodynamic cavitational reactor with biodegradability...

Water generated from the fish processing industry is contaminated with organic matter. This organic matter present in wastewater increases the biochemical oxygen demand (BOD) and chemical oxygen demand (COD). A new technology, hydrodynamic cavitation (HC) is used to deal with this wastewater produced in fish processing plants. The orifice plate is used in the HC reactor to generate a cavitation effect. The intensification of this technique was carried out with the help of hydrogen peroxide (H₂O₂) and TiO₂. The treatment of this wastewater is reported in terms of percent degradation in BOD and COD and in biodegradability index (BI). Operating parameters like inlet pressure, pH, operating temperature and H₂O₂ doses were used to find the optimum condition. 15 g/L of H₂O₂ gave 69.5% reduction of COD in the 120 min of treatment that also increases BI value to 0.93 at inlet pressure 8 bar, Plate-5, temperature (30 °C), and pH 4. In the ultrasonic cavitation (UC) reactor, COD reduction is 68.7% without TiO₂ and with TiO₂ it is 71.2%. Also, this HC and UC reactor reduced CFU count to a great extent at the same operating conditions.