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Abstract Background and Aim: Municipal landfill leachate has pollutant and refractory matters. Advanced oxygen procrsses (AOPs) are one of the wastewater treatment methods which have refractory matters. The aim of this research was to evaluate the effect of ultrasound as AOP and ultrasound and H2O2 simultaneously on reduction of leachate organic load and VSS:FSS ratio. Materials and Methods: This was an experimental study. In the first stage, organic matters are determined in raw leachate collected randomly. Then samples are sonicated in an ultrasonic bath to determine sonication effect on leachate. Each 400 ml sample was sonicated in four sonication times: 10,20,30, and 40 minutes. In other sonication step, H2O2 is added in 0.05 and 0.1 mol per liter, and samples are analyzed. Each sample was analyzed before and after sonication to determine: COD, VSS and FSS. Results: The most COD reduction rate was 8.22% in 40 min sonication. When H2O2 was added (0.05 mol/lit), COD reduction was 19.60%. When H2O2 was added (0.1 mol/lit), COD reduction was 19.72%. The ratio of VSS:FSS was 2.06 in raw leachate. After 10 min sonication, VSS:FSS ratio was decreased to 1.67. When H2O2 was added (0.05 mol/lit) in raw leachate, VSS:FSS ratio is increased to 2.94. The ratio of VSS:FSS was decreased to 2.67 and 2.16 when sonication (10 and 40 min) and H2O2 (0.05 mol/lit) was used, respectively. The ratio of VSS:FSS was increased to 3.61 and 2.16 when sonication (10 and 40 min) and H2O2 (0.1 mol/lit) was used, respectively. Conclusion: The results show that ultrasound can reduce VSS in leachate as pretreatment. H2O2 as an oxidant agent can also reduce organic matters in leachate and can be affect efficiency in next step of leachate treatment.

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Aims: Leachate is a type of highly concentrated wastewater containing chemical and microbial contaminants. Leachate discharged in receiving earth and water leads to the diffusion of different types of dangerous environmental pollutions. The aim of this study was to reduce the coliform bacteria in fresh urban leachate through electrolysis equipped by copper-iron combined electrodes.

Materials & Methods: In the laboratory-experimental study, 36 fresh leachate samples were prepared from urban solid-waste collecting trucks in Gonabad using standard combined method from July to November 2015. The leachate samples were poured into a closed reactor containing three copper-iron combined electrode pairs. Data was analyzed by SPSS 18 software using one-way ANOVA.

Findings: The higher the voltage and reaction time were, the higher the coliform removal was. In 60 minutes, all three voltages removed 100% of microbial pollution. There was a significant difference between the rate of the removed coliforms through different voltages in 15, 30, and 45 minutes (p<0.05). The rates of the removed coliforms in different reaction times were significant in 10V (p=0.001) and 20V (p=0.002).

Conclusion: Through the utilization of copper-iron combined electrodes and applied proper voltages, the electro-chemical method can be used as a clean and eco-friendly method to remove the coliform bacteria from fresh leachate.