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Background andpurpose:Currently, leachate production and its management are major environmental problems associated with the operation of solid waste landfill. The aim of this study was to evaluate the efficiency of combined processes of coagulation, ozonation, and advanced oxidation using UV-activated oxone in treatment of landfill leachate of Zahedan, Iran.

Materials andmethods: This experimental-laboratory study included chemical coagulation using poly aluminum chloride (PAC), ozonation, and chemical oxidation using potassium peroxymonosulfate (oxone). For the purpose of this study, the effect of critical operating parameters on treatment of landfill leachate was investigated. These operating parameteres included: pH (3-8) and concentration of PAC (50-250 mg/l) in chemical coagulation process,time of ozonation (5-20 min), pH of solution (2-10), concentration of oxone reactant (150-750 mg/l), contact time with oxone (60-360 min), temperature (20-45ºC), and intensity of UV lamp in oxidation process using oxone (8, 15, 30 W).

Results: According to the results, the overall efficiency rates of this process in removal of total coliform, fecal coliform, total phosphorus, total nitrogen, biochemical oxygen demand (BOD), and chemical oxygen demand (COD)were 99%, 99%, 97%, 100%, 91.1%, and 85.62%, respectively, with optimum
PAC concentration= 250 mg/L, pH= 6 at the chemical coagulation phase, ozonation duration= 20 min,
reactiontime= 180 min during oxone-based oxidation process, oxone concentration= 750 mg/L, pH= 5, temperature= 25ºC, and UV lamp intensity= 8 W. Furthermore, the BOD₅/COD ratio increased from 0.42 to 0.72 after completion of the treatment process.

Conclusion:Current study showed that application of combined processes of chemical coagulation, ozonation, and advanced oxidation using UV-activated oxone are highlyefficient in removing major pollutants from waste landfill leachate.

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Background and purpose: Pharmaceutical products, particularly antibiotics are emerging contaminants that cause major environmental challenges due to cumulative effects, different adverse effects, and leading to drug resistance. The aim of this experimental study was to evaluate the efficiency of advanced oxidation process by persulfate activated by UV in removal of ofloxacin from aqueous solutions.
Materials and methods: In order to investigate the removal efficiency of ofloxacin, major operating parameters including initial pH of solution (2-12), the concentration of persulfate (50-3500 mg/l), concentrations of ofloxacin (2-100 mg/l), reaction time (6-30 min), and UV radiation (8,15,30 Watt) were studied.
Results: Maximum removal efficiency of ofloxacin and COD in optimal conditions (pH =6, persulfate concentration = 350 mg/l, ofloxacin concentration = 40 mg/l, reaction time =20 min and UV radiation = 8 watt) were 94.35% and 79.17%, respectively. Advanced oxidation with activated persulfate by UV, deceased the concentrations of ofloxacin and COD to 2.26 and 37.21 mg/l, respectively.
Conclusion: The results showed that using UV activated persulfate is an efficient method in removal of ofloxacin from aqueous solutions.