An Innovative Approach to the Internal Microelectrolysis (IME) Process Applied to Stabilized Landfill Leachate

Joanna Ładyńska, Małgorzata Kucharska, Jeremi Naumczyk

Conventional wastewater treatment is often insufficient in the case of mature landfill leachate. Among novel methods, internal microelectrolysis (IME) has been recently recognized as an effective method for refractory wastewater treatment. The aim of this study was the evaluation of the impact of various parameters (pH, time, types, ratios of Fe/GAC, H₂O₂ dose, the time of application and the soaking of GAC in LL) on the efficiency of the IME process applied to mature landfill leachate. As microelectrodes, waste cast-iron chips and granulated activated carbon (GAC) were used. The application of a multi-step treatment of leachates, PC > m-IME > m-IME/H₂O₂, resulted in 82.1% COD removal and a significant increase in biodegradability (BOD₅/COD rose up to 0.39). The optimal parameters were established as follows: pH 3, 120 min, ratio Fe/GAC 40/10 g/g/dm³ and ratio COD/H₂O₂ = 1/2. The results showed that the PC is a reasonable pretreatment process before IME—the improvement in total COD removal was up to 12.5%. COD removal in the IME process increased with the increase in GAC dose only up to a certain level. Also, too high doses of Fe negatively affected the efficiency of the IME process, which shows that the efficiency depends not only on the dose but also on the mass ratio of Fe/GAC. The addition of H₂O₂ significantly improved the COD removal effectiveness, especially when it was applied after 120 min of the m-IME process. The results showed also that the soaking of GAC in LL before the process did not eliminate the sorption process.

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