engleski

Multi-stage landfill leachate treatment using chemical precipitation, aeration and Fenton process

In the presence of moisture, decomposition of disposed waste occurred whereby landfill leachate of complex chemical composition are formed, depending on the type and age of waste. Percolation of rainwater through the body of the landfill leads to the migration of leachate into the soil and groundwater, causing a significant impact on the environment. Contrary to this, controlled disposal of waste in so- called sanitary landfills is extremely important, where generated leachate is much easier to manage before discharging into the surface waters or sewage systems. Therefore, the purpose of this paper was the physico- chemical characterization of leachate from the sanitary Bikarac landfill and its treatment using chemical precipitation by lime, aeration and Fenton process. The initial sample is characterized as dark brown, pH = 9.06 ; Biological oxygen demand, BOD5 = 22.12 mgO2/L ; Chemical oxygen demand, COD = 1, 753.66 mgO2/L ; Kjeldahl nitrogen, K-N = 264.32 mgN/L and ammonia nitrogen, NH3-N =º191.47ºmgN/L. According to the Croatian law the parameters of COD, K-N and NH3-N are above prescribed values for leachate discharge into the both, natural surface waters and sewage systems. After the implementation of chemical precipitation and aeration, only the COD was above the prescribed values and treated leachate cannot be discharged into the sewage systems. Furthermore, the influence of pH, concentration of Fe2+ and H2O2, and molar concentration ratio of Fenton reagents (Fe2+:H2O2) on the decreasing of COD values was also investigated. The most effective decreasing of COD using Fenton process in the amount of 40 % was achieved under optimal process conditions: pH = 3, Fe2+ : H2O2 = 1:20, and concentration of 9 mgFe2+/L. By applying the Fenton process, conditions were achieved only for the discharge of treated leachate into sewage systems.

Landfill ; Leachate ; Aeration ; Chemical precipitation ; Fenton process

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