Ammoniacal nitrogen and COD removal from stabilized landfill leachate using granular activated carbon and green mussel (Perna viridis) shell powder as a composite adsorbent.

Leachate is a liquid that is produced when water percolates through solid waste and contain dis-solved or suspended material from various dissolved materials and bio-decomposition process. This study describes the finding of ammoniacal nitrogen and chemical oxygen demand (COD) removal partially replacing the amount of activated carbon. Activated carbon is well known as a good adsorbent for the removal of COD but the cost is relatively very high. However green mussel shell is the most abundant source in the world. Due to its abundance, green mussel is one of the low-cost materials. The combination of both materials is believed to produce inexpensive and suitable composite to treat the leachate. The batch experiment results indicate that the leachate concentration of ammoniacal nitrogen was (148 mg L^–1) and that of COD (308 mg L^–1). The optimum conditions for removal of ammoniacal nitrogen and COD were determined at 120 min with 200 rpm at pH 7. The optimum ratio of activated carbon and green mussel shell is 2.5:1.5. The values of removal percentage of NH₃–N, and COD are 63% and 83%, respectively. The availability of low-cost adsorbent material like green mussel shells in the composite has helped to reduce the treatment cost, along with enhancing the adsorption capacity and is environment friendly. The Langmuir isotherm adsorption model showed a better fit with strong correlation R² = 0.9962 for COD and R² = 0.9918 for NH₃–N, respectively, which means that the adsorption of leachate on granular activated carbon-green mussel shell powder, in this study, is homogeneous with the monolayer. [ABSTRACT FROM AUTHOR]