Abstract
Landfills produce leachate which is highly polluted and harmful to health and the ecosystem. Green mussel shell (GMS) and zeolite (ZEO) mixture was investigated to minimize COD and ammoniacal nitrogen (NH3-N) concentration in leachate. The particle size of all adsorbents was between 2.00 mm and 3.35 mm. The optimal pH, mixed media ratio, and agitation speed were determined. The samples used in this analysis were obtained from the effect of the retention pond at the Simpang Renggam Municipal Landfill Site (SRLS), Johor (Malaysia). The result of leachate characterization indicates non-biodegradable leachate with high concentrations of COD (1829 mg/L), NH3-N (406.68 mg/L), and biodegradable ratio (0.07). The optimal shaking speed condition was 200 rpm, the optimum mixing media ratio of (GMS and ZEO) was 2.0:2.0, and the optimum pH was 7. The mixed media for leachate treatment reported encouraging results in the reduction of COD and NH3-N. The coefficient of determination (R-2) values described that Langmuir model experimental data fitted best as compared with the coefficient of determination (R-2) of the Freundlich model (R-2 = 0.9969) for COD and (R-2 = 0.9927) of NH3-N. The pseudo-second-order better fitted the equilibrium data over the entire concentration range studied. The pseudo-second-order kinetic model described the best coefficient of determination compared to the pseudo-first-order kinetics model. The coefficient of determination for pseudo-second-order was generally in the range of 0.9988-1.000 for 90% of all kinetics studies conducted. This implies that adsorbate adsorption occurs by monolayer adsorption on a homogeneous surface, and thus, chemisorption significantly controls the sorption process.