Identification of organic compounds in leachate from a waste tip

Abstract

Two different types of leachate from a waste tip have been researched. For that purpose some analytical methods were developed. The first type of leachate was sampled from a waste tip in the acidification stage. In this leachate the larger part of the organic load consists of free volatile acids (95 to 100% of the COD). Volatile amines and ethanol (1.2% respectively 1% of the COD) were also present. The leachate was extracted with hexane and the extract was analyzed with infrared and nuclear magnetic resonance spectrometrie and a gaschromatograph-mass spectrometer combination. In the extract alcohols, oil, esters, terpenes and phtalates have been identified. High molecular compounds were only present in a low concentration. The second leachate, taken from a waste tip in the methane fermentation stage contained much more high molecular compounds. About 32% of the organic carbon consists of compounds with a molecular weight over 1000. In this water no acids, amines and alcohols could be detected. This means that the organic compounds were end products of degradation processes. Furthermore there was a remarkable difference in heavy metal content between the two leachate types.

Fractionnement et caractérisation de la matière organique des lixiviats de décharges d'ordures ménagères

“…Les méthodes de classification généralement utilisées pour les composés organiques se basent le plus souvent sur la différence des masses molaires des composés. Le fractionnement de la matière organique est effectué soit par ultrafiltration (SLATER et al, 1985) soit par perméation sur gel de type Séphadex G (CHIAN, 1977 ;CHlAN et DEWALLE, 1977 ;GOURDON, 1987 ;GOURDON et al, 1989 ;GRANET et al, 1985 ;LAURET étal., 1989 ;MILLOT, 1986), ou encore à l'aide des solvants organiques (CHIAN et DEWALLE, 1977 ;HARMSEM, 1983 ;MURRAY et BECK, 1990 ;SHAWNEY et KOZLOSKI, 1984). La séparation des composés peut être effectuée également par chromatographie liquide à haute pression CLHP (GOURDON et al, 1989) ou par adsorption sur résine macroporeuse Amberiite XAD-4 (LAURET étal., 1989).…”

Traitement de lixiviats stabilisés de décharge par des membranes de nanofiltration

“…Les lixiviats conservent une DCO récalcitrante (500 à 1 500 mg Og/L -1 ), appelée « DCO dure » (CHIAN, 1977 ;HARMSEN, 1983 ;GOURDON, 1989et MEJBRI, 1996.…”

Decomposition and mineralization of aquatic humic substances (AHS) in treating landfill leachate using the Anammox process

“…Contents of the two fractions in leachate vary greatly depending on the landfill age. In young landfills, a majority of organic carbon is present as VFA, as much as 95% of the organic content (Harmsen, 1983). In mature landfills, however, humic-like compounds dominate the organic fraction in methanogenic leachate, as much as 60% (Artiola-Fortuny and Fuller, 1982).…”

“…Landfill leachate from sanitary landfill site contains a lot of dissolved organic matter (DOM), mainly including volatile fatty acid (VFA) and aquatic humic substance (AHS) such as fulvic acids (FA) with a relatively high carboxyl and aromatic hydroxyl group density, and humic acids (HA) with a significant amount of hydrolysable amino acids (Harmsen, 1983). Contents of the two fractions in leachate vary greatly depending on the landfill age.…”