Influence of Landfill Operation and Tropical Seasonal Variation on Leachate Characteristics: Results from Lysimeter Experiment

This study demonstrates the influence of lysimeter operational condition and tropical seasonal variation of leachate characteristics generated from municipal solid waste (MSW) deposited in landfill lysimeter at KUET campus, Bangladesh. Three different situations of landfill were considered here as well as both the open dump lysimeter-A having a base liner and sanitary landfill lysimeter-B and C at two different types of cap liner were simulated. The leachate characteristics, leachate generation and climatic influence parameter had been continually monitored, from June 2008 to May 2010. This period covers both dry and rainy season. The leachate generation followed the rainfall pattern and the open dump lysimeter-A without top cover was recorded to have the highest leachate generation. Moreover, the open dump lysimeter-A had lower concentration and load of total kjeldahl nitrogen (TKN), ammonia nitrogen (NH4-N) and dissolved organic carbon (DOC), while chemical oxygen demand (COD) and biological oxygen demand (BOD5) concentration were higher compared with sanitary lysimeter-B and C. On the other hand, sanitary lysimeter-B, not only had lowest leachate generation, but also produced reasonably low COD and BOD5 concentration compared with open dump lysimeter-A. Based on evaluated results, it was also concluded that metal concentrations which were comparatively higher in leachate of open dump lysimeter were Ca and K, however, the heavy metal concentrations of Cd, Cu, Zn and Mn, and those apparently lower were metals of Na, Mg and Fe as well as heavy metals of Cr, Pb and Ni. However, significant release of heavy metals under open dump lysimeter was observed compared to sanitary lysimeter. Moreover, meaningful correlation between DOC and leaching of Cu and Pb was observed. Result reveals that lysimeter operational mode had direct effect on leachate quality. Finally, it can be concluded that the knowledge of leachate quality will be useful in planning and providing remedial measures of proper liner system in landfill design and leachate treatment.