Hydrodynamic Cavitation and Advanced Oxidation for Enhanced Degradation of Persistent Organic Pollutants: A Review

Abstract

Water pollution has become a major environmental menace due to municipal and industrial effluents discharged into water bodies. Several processes have been devised for the treatment and disposal of wastewater and sludge. Yet, most of the conventional technologies do not meet the requirements of sustainability as they impose a higher load on the environment in terms of resource depletion and toxic waste generation. Recently, sustainable innovative technologies, like hydrodynamic cavitation (HC), have emerged as energy-efficient methods, which can enhance the conventional wastewater treatment processes. HC is a very effective technique for the intensification of processes, like aeration, activated sludge treatment, and anaerobic digestion processes in conventional wastewater treatment plants, particularly for the enhanced degradation of persistent pollutants. On the other hand, advanced oxidation is a proven enhancement method for wastewater treatment. This review provides a comprehensive overview of recently published literature on the application of HC for the treatment of persistent organic pollutants. The potential synergistic impact of HC coupled with advanced oxidation and alternative pre-treatment methods was also reviewed in this study. Moreover, an overview of the present state of model-based research work for HC reactors and a feasibility analysis of various advanced oxidation process is also covered. Options for the pilot-to-large scale implementation of HC and advanced oxidation technologies to ensure the better sustainability of wastewater treatment plants are recommended.