Landfill leachate treatment in an integrated adsorption-chemical oxidation process including CNT and nZVI-H2O2

Landfill leachate has created many health and environmental concerns. This paper aimed at examining the efficiency of two batch systems, including multiple carbon nano-tubes (MCNT) as a first reactor and “nano-particles of zero valent iron (nZVI) + H2O2” processes as a second reactor, for treatment of very strong landfill leachate with the following physiochemical characteristics: 85,000 mg/L chemical oxygen demand (COD), 20,000 mg/L 5-d biological oxygen demand (BOD5), 200,000 mg/L total solids (TS), and 15,000 TCU color. Experiments were performed in two series batch reactors and main influencing factors, pH, reaction time, concentration of iron and H2O2 were investigated. The results display the high potential of absorbing organic materials in leachate by carbon nano-tubes in the first stage of treatment (58% COD, 82% color and 33% TS are reduced within 10 min). The highest obtained removal efficiencies with this two-stage novel system was 83.6%, 40%, 76.81% , 90.6% for COD, BOD5, TS and color, respectively. In addition, nZVI + H2O2 process in the second stage of treatment can be applied for landfill leachate because it can augment the BOD5/COD ratio and increase the biodegrability of this type of wastewater.