4. Conclusions
This study has successfully examined the treatment of landfill
leachate via coagulationeflocculation purification methodology
using lateritic soil as a coagulant and alum as a comparative
coagulant. The lateritic soil coagulant was enriched with aluminum
ions and iron ions (cationic ions) that destabilize the colloidal and
suspended particles in the liquid media such as landfill leachate, via
a coagulation mechanisms relying on adsorption and charge
neutralization plus inter-particle bridging. The optimum pH for
using the lateritic soil as a natural coagulant was 2.0, with a coagulant
dosage of 14 g/L. The lateritic soil coagulant was also able to
remove 65.7% COD and 81.8% color from the landfill site leachate
under an optimum pH and coagulant dosage. Alternatively, the
alum coagulant removed 85.4% COD and 96.4% color from the same
leachate sample under optimized conditions (pH 4.80 and alum
dosage of 10 g/L). Additionally, alum as a chemical coagulant
reduced the concentration of ammoniacal nitrogen by 47.6%, while
lateritic soil reduced it by 41.2%. In addition, the ratio of alum to
lateritic soil was determined as 53:1 throughout this research
project, where the SVI of alum coagulant was 128.1, while it was 2.4
for the lateritic soil under optimized conditions.