Enhancing wastewater treatment efficiency through hydrodynamic cavitation and advanced oxidation processes: Experimental insights and comparative analysis

Abstract

Background

The escalating industrial wastewater production mandates effective treatment methods to mitigate environmental and health risks. Hydrodynamic cavitation (HC) and its combination with advanced oxidation processes (AOPs) offer promising approaches for wastewater pollution reduction.

Methods

This study investigates the enhancement of HC efficiency for Chemical Oxygen Demand (COD) reduction by integrating hydrogen peroxide (H₂O₂) and air injection. Synthetic wastewater resembling industrial effluent COD levels serves as the experimental medium. Varied inlet pressures, H₂O₂ concentrations, and air injection rates were examined to gauge their impact on COD reduction.

Significant Findings

Higher inlet pressures directly correlate with increased COD reduction, highlighting intensified cavitation effects. Combining HC with H₂O₂ or air, especially when directly injected into the venturi throat, showcased substantial synergy, significantly reducing COD levels. Notably, the maximum extent of COD reduction, achieved at 51.85 %, was with the combination of (HC+H₂O₂+Air). The COD reduction percentages for other processes, including HC alone, (HC+Air tank injection), (HC+Air throat injection), (HC+H₂O₂ tank injection), and (HC+H₂O₂ throat injection), were 4.21 %, 19.7 %, 20.9 %, 37.8 %, and 39.4 %, respectively.