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Landfill leachate contains complex, resistant, and diverse compounds that are considered as an environmental health problem. This study aims to investigate the efficacy of integrated homogeneous catalytic ozonation and electrochemical process for improving the biodegradability of landfill. This experimental study was conducted on real landfill leachate on the laboratory scale. The variables were current density (O 3 /H 2 O 2 -42.1 mA/cm2), ozone concentrations (100–400 mg/h), the initial pH (3–9), and the reaction times (1–6 h). The optimum operating condition was obtained at 1.42 mA/m2, 400 mg/h of ozone concentration, initial pH of 3, during 3 h. In the proposed integrated catalytic ozonation-electrochemical process, the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentrations were removed to 3381.9 and 1521.8 mg/L, respectively. Under the optimum condition, the biodegradability index increased from 0.27 to 0.45. The results showed that the electro-catalytic ozonation process has a significant effect on the biodegradability index and could improve the removal efficiency of landfill leachate treatments. Image 106 • The electro-catalytic ozonation process was found to be effective for the pretreatment of landfill leachate. • Increasing of biodegradability index from 0.27 to 0.45 • The optimum condition in the integrated system was obtained during 6 h. • The electrical conductivity was increased during the process. [ABSTRACT FROM AUTHOR]

The present work proposes an ultrasound (US) assisted electro-Fenton (EF) process for eliminating penicillin G (PNG) and ciprofloxacin (CIP) from aqueous solutions and the process was further optimized by response surface methodology (RSM)- Box-Behnken design (BBD). The impact of pH, hydrogen peroxide (H 2 O 2) concentration, applied voltage, initial pollutant concentration, and operating time were studied. The capability application of the electro-Fenton (EF) and US processes was compared separately and in combination under the optimum conditions of pH of 4, a voltage of 15 V, the initial antibiotic concentration of 20.7 mg/L, H 2 O 2 concentration of 0.8 mg/L, and the operating time of 75 min. The removal efficiency of PNG and CIP using the sono-electro-Fenton (SEF) process, as the results revealed, was approximately 96% and 98%, respectively. The experiments on two scavengers demonstrated that ⦁OH contributes significantly to the CIP and PNG degradation by SEF, whereas ⦁O− 2 corresponds to only a negligible amount. The total organic carbon (TOC) and chemical oxygen demand (COD) analyses were used to assess the mineralization of CIP and PNG. The efficiency of COD and TOC removal was reached at 73.25% and 62.5% for CIP under optimized operating circumstances, and at 61.52% and 72% for PNG, respectively. These findings indicate that a sufficient rate of mineralization was obtained by SEF treatment for the mentioned pollutants. The reaction kinetics of CIP and PNG degradation by the SEF process were found to follow a pseudo-first-order kinetic model. In addition, the human health risk assessment of natural water containing CIP and PNG that was purified by US, EF, and SEF processes was done for the first time. According to the findings, the non-carcinogenic risk (HQ) caused by drinking purified water by all three systems was calculated in the acceptable range. Thus, SEF is a proper system to remove various antibiotics in potable water and reduces their human health risks. [Display omitted] • More than 96% of studied antibiotics were removed by sono-electro-Fenton. • Based on Box–Behnken design, pH was the most vital factor for antibiotics removal. • The antibiotics degradation by the process followed a pseudo-first-order model. • By increasing time, the antibiotics were more mineralized and biodegraded. • The water source treated by the system had no non-carcinogenic risk to consumers. [ABSTRACT FROM AUTHOR]