Landfill leachate treatment using hydrodynamic cavitation: exploratory evaluation

Effect of the association of coagulation/flocculation, hydrodynamic cavitation, ozonation and activated carbon in landfill leachate treatment system

“…The increments from the 2nd to 3rd hour of system operation in efficiency were smaller compared to the increment from the 1st to 2nd hour, being 5.4% for COD, 10.8% for turbidity and 3.1%, being similar in the other times tested (Table 2 ). Similar observations were reported by Huo et al 2008, Gutiérrez-Mosquera et al 2022 and Wang et al 2021 which can be associated with the decreased fluid flow causing the cavitation device to be filled with water, leading to higher static pressure and early collapse of cavities 18 , 22 , 52 . Also, Huo et al 2008 observed that longer operational times can drive aromatic polycondesantion which increases the DOM humidification causing an increase in the COD values in the system 52 .…”

“…When associated to ozonation the process contributes for rapid absorption of ozone molecules in the system. The combined process of cavitation with ozone produces ·OH radicals therefore can significantly improve the degradation efficiency of the process 18 , 22 , 52 .…”

“…Due to the environmental pressure to comply with extremely restrictive standards, aiming to reach an effluent quality compatible for reuse, launching in water courses or in conventional sewage collection systems, a combination of techniques with synergy to generate a high efficiency is hugely necessary. With the evolution of the studies, Advanced Oxidative Processes (AOPs) and Hydrodynamic cavitation emerge as promising strategies to solve the environmental and human health problems of effluents with high treatment complexity 16 – 18 .…”

“…Hydrodynamic cavitation proved to be a promising technique, used in many fields, such as disinfection, cell rupture, sludge treatment, degradation of organic compounds, however, wastewater treatment is a recent practice and that, together with other technologies, has proven to be promising in increasing efficiencies and reducing treatment costs 22 – 24 . Research shows that the application of hydrodynamic cavitation in the treatment of landfill leachate in isolation, despite the increase in COD removal efficiency, did not achieve good results, requiring a combination of techniques 18 .…”

A novel process for landfill leachate pretreatment using hydrodynamic cavitation combined with potassium ferrate oxidation

“…However, HC is more commonly used in combination with AOPs or oxidants to obtain better leachate treatment results. Luis et al 26 combined HC with 200 ppm H 2 O 2 at a 3 bar inlet pressure for 30 min, achieving 38.21% and 51.55% removal of COD and BOD 5 from landfill leachate. Wang et al 27 combined HC with 25 mg/L chlorine dioxide at pH 5 and an inlet pressure 0.4 MPa for 120 min, resulting in 58.82% COD removal from landfill leachate coagulation effluent.…”