Metal speciation in landfill leachates with a focus on the influence of organic matter

Abstract

This study characterises the heavy-metal content in leachates collected from eight landfills in France. In order to identify heavy metal occurrence in the different size fractions of leachates, a cascade filtration protocol was applied directly in the field, under a nitrogen gas atmosphere to avoid metal oxidation. The results of analyses performed on the leachates suggest that most of the metals are concentrated in the <30 kDa fraction, while lead, copper and cadmium show an association with larger particles. Initial speciation calculations, without considering metal association with organic matter, suggest that leachate concentrations in lead, copper, nickel and zinc are super-saturated with respect to sulphur phases. Speciation calculations that account for metal complexation with organic matter, considered as fulvic acids based on C1(s) NEXAFS spectroscopy, show that this mechanism is not sufficient to explain such deviation from equilibrium conditions. It is therefore hypothesized that the deviation results also from the influence of biological activity on the kinetics of mineral phase precipitation and dissolution, thus providing a dynamic system. The results of chemical analyses of sampled fluids are compared with speciation calculations and some implications for the assessment of metal mobility and natural attenuation in a context of landfill risk assessment are discussed.

Pendugaan Distribusi Air Lindi dengan Geolistrik Metode ERT di TPA Piyungan, Bantul, DIY

“…Penggunaan lahan juga merupakan sumber pencemar potensial dan bersifat dinamis, sehingga penggunaan lahan berupa TPA termasuk penyebab kualitas airtanah sekitar menjadi buruk (Widyastuti et al, 2006). Airtanah yang tercemar oleh air lindi umumnya mengandung mineral tinggi, terutama unsur kimia seperti sulfida (Claret et al, 2011). Oleh karena itu, tingginya nilai DHL, salinitas, dan TDS di beberapa sumur sekitar TPA Piyungan mengindikasikan bahwa airtanah di lokasi tersebut telah terkontaminasi oleh air lindi.…”

Fluctuation of dissolved heavy metal concentrations in the leachate from anaerobic digestion of municipal solid waste in commercial scale landfill bioreactors: The effect of pH and associated mechanisms

“…The majority of these studies present snapshots of heavy metal speciation in leachate with discrete ages from either operating or closed mature landfills [6,[11][12][13][14][15][16].…”

“…humic acids) and the influence of biological activity (e.g., sulphate reducing bacteria). Although there have been many attempts to model these interactions and subsequent metal distributions, model simulations are hindered by insufficient certainty regarding solubility product constants [11]. Furthermore, few studies report on the fluctuation of dissolved heavy metal due to the interaction of multiple factors during anaerobic digestion in landfill bioreactors [17].…”

Inhibition of anaerobic ammonium oxidation by heavy metals

“…Elevated concentrations of heavy metals (HMs), including divalent copper (Cu), zinc (Zn), nickel (Ni), cadmium (Cd) and lead (Pb), are generally found in municipal landfill leachates. Figure summarizes the results of an extensive literature review performed in this study to determine the typical concentration ranges at which HMs are detected in landfill leachates . This survey considered literature data on the composition of leachates in 13 different municipal landfills located in 11 different countries.…”