Identification of organic compounds in leachate from a waste tip

Abstract

Two different types of leachate from a municipal waste tip have been analyzed. The first type of leachate was collected from a waste tip in the acidification stage. The organic load of this leachate was high and consisted mainly of free volatile acids (over 95% of the TOC). Volatile amines and ethanol were also present (0.8 and 0.7% of the TOC respectively). The leachate was extracted with hexane and the extract was analyzed with infrared and nuclear magnetic resonance spectroscopy and a gas chromatograph-mass spectrometer combination. In the extract alcohols, hydrocarbons, esters, terpenes and phthalates have been identified. High molecular weight compounds were present only in a low concentration. The second type of leachate was collected from a waste tip in the methane fermentation stage. The organic load was relatively low. An important part of the organics was identified as high molecular weight compounds. About 32% of the organic carbon consisted of compounds with a molecular weight over 1000. Acids, amines and alcohols could not be detected. This means that the organic compounds present were end products of degradation processes. Furthermore there was a remarkable difference in heavy metal content between the two types of leachate.