Microbiological Processes in Landfills

Abstract

Large landfills in the Soviet Union cover more than 140 thousand hectares. The gas emission intensities are extremely disproportional over the surface of these landfills. According to our data the rates of streams of the biogas components vary from 0 till 20, 46, 1.2 and 0.75 (×10−4m3 × hour −1/m2) for CH4, CO2, H2, CO, respectively. The stable carbon isotope composition of methane and carbon dioxide in the biogas of deep landfills layers is typical for methanogenesis from organic wastes, but it depends on the concentration of organic substance in the landfill ground and on the age of these landfills. In the upper layer methane becomes heavier and carbon dioxide lighter due to the microbiological oxidation processes. The most intensive methanogenesis is usually observed in the upper part of the anaerobic zone where the organic substance concentration is relatively high. The methanogenic microflora is represented by mesophilic methanobacteria, species of Methanosarcina and Methanobacterium genera are prevalent forms. At the depth of 10-100 cm from the surface intensive oxidation of methane, hydrogen and carbon monoxide is observed. The number of gas oxidizing bacteria is up to 10 cells per gram of soil. 14 species of methane oxidizing bacteria, which belong to 5 genera were iden tified. Hydrogen oxidizing bacteria belong to Alcaligenes,Pseudomonas, Paracoccus, Mycobacteriun genera. Between them psychrotrophic forms were found. It has been shown that in small landfills methane, produced in anaerobic zone, can be oxidized completely in the upper ground layer. The biogas extraction from landfills is important not only as an additional fuel source, but as a means of preventing pollution of the Earth's atmosphere.

A Comprehensive Numerical Model Simulating Gas, Heat, and Moisture Transport in Sanitary Landfills and Methane Oxidation in Final Covers

“…Further, these models do not consider methane movement and its oxidation in the final cover, although there are models developed independently for this purpose [33,34,42]. Methane oxidation in covers can range between 10% and 70% of methane generated in a landfill [11,23,30,51].…”

Treatment of municipal solid wastes leachate by means of chemical- and electro-coagulation

“…In the solid waste management, landfill is one of the most prevalent methods used by many countries in the world [1]. With approximate calculations, it is found that 450-500 million tonnes of domestic solid waste is produced annually in the world [2]. Three hundred and twenty to three hundred and fifty million tonnes of this, that is equivalent to 70%, is removed by landfill [3].…”

Landfill Methane Oxidation in Engineered Soil Columns at Low Temperature

“…Microbial CH 4 oxidation depends on several abiotic variables such as the soil's water content, temperature, CH 4 concentration, oxygen (O 2 ) availability, and nutrients concentrations Bogner et al, 1997b;Börjesson et al, 1998a;Börjesson et al, 2004;Christophersen et al, 2000;Czepiel et al, 1996a;De Visscher et al, 2001;Figueroa, 1993;Hilger et al, 2000;Kightley et al, 1995;Nozhevnikova et al, 1993;Watzinger et al, 2005;Whalen et al, 1990). Less attention has been paid to soil texture and physical characteristics such as compaction and air-filled porosity (Figueroa, 1993;Kightley et al, 1995), which all affect the movement of gases in soil (Hillel, 1998) and thus CH 4 oxidation in the field.…”