Change in Chemical Compositions of Leachate and Medium Density Fiberboard from a Laboratory-scale Simulated Landfill

The change in chemical compositions of leachate and medium density fiberboard (MDF) from a labo-ratory-scale simulated landfill which constructed in a plastic container containing alternating layers of soil and MDF was investigated to evaluate decomposing of MDF in soil. Four treatments were conducted: 1) MDFin soil, 2) MDF only, 3) cured UF resin in soil, and 4) soil only. Molecular weight (MW) distribution ofcompounds in leachate from soil only treatment did not change over time. In UF resin in soil treatment, the MW distribution shifted to a lower MW distribution over time, while the peak shifted to the left indicated changing to higher MW distribution in leachate from treatment 1 and 2 contained MDF. Higher percentnitrogen in leachate was observed in MDF containing treatments due to the UF resin in the MDF. The percentcarbon slightly increased in MDF only while that greatly decreased in MDF in soil treatment maybe due to bacterial activity. The percent of extractable materials from the MDF decreased greatly on day 35 compare to day 0, and subsequently did not change much on day 77. In contrast, percent holocellulose and lignin did not change much over time. No structural change of the wood fiber in MDF occurs during the study. Water-solublematerials from MDF in soil contributed the change in chemical composition of leachate.Keywords : simulated landfill, leachate, medium density fiberboard, urea-formaldehyde resin, chemical analysis, elemental analysis