Optimization of Ozonation Process for a Composting Leachate-Contaminated Soils Treatment Using Response Surface Method

Abstract

The ozonation process has become one of the most favorable processes among soil remediation technologies nowadays. Ozone, which has an oxidation potential of 2.07 V and acts as a powerful oxidizer, is capable of degrading organic pollutants of soil in a short period of time without producing any toxic residuals. In this study the capability of ozone, as an ex-situ method of soil treatment, in remediating the leachatecontaminated soil has been investigated. To maximize the removal efficiency of organic content of soil, design of experiments using the response surface method (RSM) and central composite design (CCD) have been employed. To select the range of effective parameters several experiments were performed at laboratory scale. Results showed a range of effective parameters on the ozonation process, including pH, humidity, and initial soil pollution. Present research shows that acid-washed ozone greatly enhanced the removal efficiency. According to the developed model, the maximum removal efficiency using acid-washed ozone was obtained by setting the parameters as pH = 10.8, humidity of 5% and initial organic content of soil to be 7720 mg/kg. Confirmation experiments showed that RSM could be effectively utilized for the optimization of the ozonation process. Analysis of variance also showed that pH was the most significant factor affecting removal efficiency.

Enhanced treatment of 2-methylpropane-2-thiol contaminated soil using magno-modified fenton process

“…x x x x (25) Analysis of variance Analysis of variance based on the results from Table 1, is summarized in Table 2. Because the significance level (α) is 0.05 with a specified degree of freedom (DF), P-value smaller than 0.05 shows that the factor is effective on the removal efficiency [29].…”

“…Central composite design was used as an experimental design model, with response surface methodology used for the design of the experiment. Mathematical modeling resulted from the applied method to predict the optimal experimental condition [25].…”

Composting leachate: characterization, treatment, and future perspectives

“…(Mokhtarani et al 2016). In addition to being the first to report the use UV/TiO 2 in composting leachate post-treatment, Mokhtarani et al (2015) also chose to immobilize the TiO 2 nanoparticles on a concrete surface. After 21.5 h of radiation with 7.5 mW/cm 2 light intensity, the maximum COD and colour removal achieved were 58 and 36%, respectively.…”

“…However, composting at the industrial scale generates large volumes leachates. While the compost itself can be reused as a beneficial soil amendment, composting leachates contain various hazardous substances that can have potential adverse effect on the environment, and that therefore need to be sufficiently treated prior to disposal (He et al 2015;Mokhtarani et al 2015).…”