Municipal landfill leachate (MLL) contamination in surface water is a critical global issue due to the high concentration of toxic organics and recalcitrants. The biological treatment of MLL is ineffective due to an elevated concentration of ammoniacal nitrogen, which restricts the production of the recalcitrant degrading laccase enzyme. In this context, integrating an external laccase-anchored carbon catalyst (LACC) matrix system with the microbial system could be an efficient strategy to overcome the drawbacks of conventional biological MLL treatment technologies. In the present study, the LACC matrix was synthesized by utilizing nanoporous activated carbon (NAC) functionalized ethylene diamine (EDA) and glutaraldehyde (GA) (GA/EDA/NAC) matrix for the anchoring of laccase. The maximum anchoring capacity of laccase onto GA/EDA/ NAC was achieved to be 139.65 U/g GA/EDA/NAC at the optimized anchoring time, 60 min; pH, 5; temperature, 30 °C, and mass of GA/EDA/NAC, 300 mg and was confirmed by Fourier transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM), and X-ray Diffraction (XRD) analyses. Further, the mechanistic study revealed the involvement of covalent bonding in the anchoring of laccase onto the functionalized surface of the GA/EDA/NAC matrix. The adsorption isotherm and kinetics of laccase anchoring onto the GA/EDA/NAC matrix were performed to evaluate its field-level application. Subsequently, the sequential microbial system (I-stage bacterial treatment followed by II-stage fungal treatment) and III-stage LACC matrix system could effectively reduce the COD by 94.2% and phenol by 92.36%. Furthermore, the Gas Chromatography-Mass Spectrophotometry (GC–MS) and FT-IR analyses confirmed the effective degradation of organic compounds and recalcitrants by the integrated microbial and LACC matrix system. The study suggested that the application of the LACC matrix system has resulted in the complete treatment of real-time MLL by overcoming the negative interference of elevated ammoniacal nitrogen concentration. Thus, the integrated microbial and LACC matrix approach could be considered to effectively treat the MLL without any secondary pollution generation.

An experimental research was conducted in order to study the treatability of municipal landfill leachate using a combined physio-chemical and biological treatment. The leachate was obtained from Nanjido landfill site in Seoul. Several sets of bench-scale sequencing batch reactor(SBR) and physio-chemical reactors were used as experimental apparatus. This experiment lasted for about 2 years. The results are as follows: 1. The characteristics of Nanjido landfill leachate were pH 7.4∼8.2, BOD 79∼450㎎/L, COD 998∼1460㎎/L, NH_3-N 1380∼3412㎎/L, T-P 2.6∼7.O㎎/L, color 890∼1992 unit, and heavy metals are a very small amount. 2. Either physio-chemical or biological treatment of Landfill leachate alone did not work well. So for the adequate treatment of leachate, it was necessary to deal with the physio-chemical pretreatment before biological treatment. And it was found that both electrolysis and ozone treatment are better pretreatments of leachate than others. 3. In this study, landfill leachate was effectively processed by two step : first by electrolysis pretreatment, and secondly by SBR treatment. Thus, the study showed considerable substrate removal of raw leachate, even though the rate of COD removal depended on HRT.

Leachate from municipal landfill site is known to be hard to treat because it commonly contains various toxic material and heavy metals. In addition, portions of biodegradable organic substances in leachate are decreasing in the course of wastes stabilization, which is one of the critical reason for inefficient biological treatment at the end stage of landfill site operation. So this study was conducted to examine the feasibility of municipal landfill leachate pretreatment using electrolysis. The optimum electrode combination was made. The optimum electrode combination was found to be lead and graphite.