Experimental research on the degradation of chemical industrial wastewater by combined hydrodynamic cavitation based on nonlinear dynamic model

Abstract Based on the self-developed combined hydrodynamic cavitation device composed of a Venturi tube with variable throat length-to-diameter ratios, a triangular orifice perforated plate and nonlinear dynamic model, the influences of factors such as the throat length-to-diameter ratio, cavitation number, orifice size, orifice quantity, initial concentration of raw water, and pH value on the degradation of chemical industrial wastewater by hydrodynamic cavitation were experimentally studied. Combined with the actual situation of chemical wastewater treatment, a nonlinear dynamic model of the hydraulic cavitation process was established, and the influence of different operating parameters on degradation effect was analyzed. The results showed that the extreme conditions generated during the collapse of cavitation bubbles could cause cavitation erosion damage to the refractory pollutants in chemical industrial wastewater. When the throat length-to-diameter ratio of the Venturi tube was L / R = 20, increasing the number of orifices (49 orifices) of the downstream perforated plate and reducing the orifice diameter (4.04 mm) were beneficial to the treatment of high-concentration wastewater. When the throat length-to-diameter ratio of the Venturi tube was L / R = 40 or 60, appropriately reducing the number of orifices (16 or 25 orifices) and increasing the orifice diameter (6.73 mm) could achieve the optimal degradation of high-concentration wastewater.