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Background: The growth of population, improvement of quality of life and the development of industries have led to increase in the rate of urban and industrial waste. As the leachate of the waste has a lot of pollution, influences harmfully human health and the environment. Researches have shown that the advanced oxidation processes (AOPs) such as Fenton and Fenton-related processes can reduce chemical oxygen demand (COD) of the leachate effectively.

Materials and Methods: In this paper, the rate of decrease in the total suspended solids (TSS) of leachate from a composting facility in Isfahan was studied using electrochemical, Fenton and electro-Fenton processes. These processes were conducted at reaction times 0, 20, 40, and 60 minutes, with the currents of 0.5, 1 and 1.5A and hydrogen peroxide dosages 1000, 2000, and 3000 mg/L.

Results: In the three mentioned processes, the most TSS removal was observed at the first 40 minute of the reactions. Among the studied processes, the electro-Fenton removed up to 92.4% of the TSS and was recognized as the most effective method. Furthermore, electrochemical and Fenton removed 41.7% and 60.3% of the TSS, respectively.

Conclusion: Therefore, decreasing the TSS of leachate could change its qualities and reduce the leachate pollution and the adverse environmental effects.

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Background: and Aim The leachate from oil sludge compost into the environment, which is resistant to decomposition, causes several environmental problems. Therefore, it needs to be treated using efficient processes. This study aimed to investigate the efficiency of the modified Fenton process for treating these oil sludge leachates.
Methods & Materials: In this experimental study, leachate samples were collected, and then modified Fenton solution was prepared by adding Fe2 (SO4) 3 to H2O2. Then the effect of time parameters (15, 30, 60, 90, and 120 minutes), modified Fenton concentration of 20, 50, 100, and 200 mg/l with pH 3, 5, 9, and three initial concentration of COD (500, 1000 and 1500 mg/l) was examined.
Ethical Considerations: This study has been registered in Arak University of Medical Sciences with codes 2645 and 2765.
Results: The reduction of COD and TPH in the optimal time of 60 minutes, initial COD of 500 mg/l, pH of 3, and Fenton concentration of 200 mg/l were 9.04 and 77.42%, respectively. The experiments showed that the removal efficiency of COD and TPH with increasing residence time and the concentration of modified Fenton are directly proportional and with decreasing, the initial concentration of COD and pH is inversely proportional.
Conclusion: The use of modified Fenton is an efficient method for treating leachate from petroleum sludge compost.