Surfactant Degradation using Hydrodynamic Cavitation based Hybrid Advanced Oxidation Technology: A Techno Economic Feasibility Study

Abstract Surfactant degradation is a challenging problem related to wastewater treatment. The source of such wastewater can be industrial or domestic, with concentrations varying in between 1 to 300 mg/L. Due to the sheer volume of such streams, both kinetics of degradation as well as scale of operation become the governing criteria for the success of a technology. In this work, the authors have reported for the first time, the possibility of treating surfactant (sodium dodecyl sulphate, SDS) laden wastewater using hydrodynamic cavitation (HC) technology. A systematic approach has been adopted whereby the following modus operandi were taken: (i) selection of orifice diameter for HC treatment, (ii) studying the effect of pH and inlet pressure for SDS degradation using HC, (iii) effect of varying SDS concentration (2, 5, 10 and 15 mg/L) and subsequent degradation studies, (iv) addition of H2O2 along with HC and optimization and (v) addition of Fenton at various ratio in the optimized HC systems. It was observed that (i) 1.6 mm was the optimum orifice diameter for carrying out HC process, (ii) pH = 2 and pressure = 5 bar were the optimized operating conditions for HC process, (iii) 5 g/L H2O2 was the optimized concentration for HC+H2O2 system, (iv) By coupling HC process with Fenton:H2O2 = 1:3 ratio, 99.46% SDS degradation was obtained within 60 min. This result is encouraging at laboratory scale and further investigation and understanding of such a technology can definitely help in providing scaled up solutions both for domestic and industrial applications.