The role of aerobic activity on refuse temperature rise, I. Landfill experimental study

Abstract

The temperature field in a landfill situated in the south of France has been characterized and analysed. Sixty‐four probes, measuring temperature and gas composition, were placed directly in municipal solid waste during the filling of a 200 000‐m3 cell and the spatial and temporal temperature variations recorded. The average temperature increase was about 20°C. It occurred within the first 20 days. The thermal properties of the waste (conductivity and diffusivity) were measured with a thermal shock probe. A heat balance shows the predominant role of oxygen diffusion and aerobic reactions in the rising temperature.

The role of aerobic activity on refuse temperature rise: II. Experimental and numerical modelling

“…As a result, this experimental simulation confirms the observations and the heat balance in landfills (Lefebvre et al, 2000): • the increase of the waste temperature during landfilling occurs with the aerobic decomposition of freshly disposed refuse; • the thickness of the aerobic zone obviously depends on both the biological oxygen consumption and the oxygen diffusion rates; a vertical oxygen gradient appears rapidly within two days and consequently, the temperature increases rapidly, then remains stable after two weeks; and • most of the accumulated heat is then conserved in anaerobic conditions because of the low thermal conductivity of the waste.…”

“…The absence of aerobic A rough thermal balance showed that 80% of the heat accumulated in the waste was provided by the consumption of the oxygen transferred inside the model waste during filling (for details on the calculations, see Lefebvre et al 2000). Initially, the pores of the new fresh model waste were full of oxygen (21%) and from 10 cm depth, the oxygen concentration decreased rapidly with increasing depth.…”

“…A model refuse was defined according to the global composition of the waste stored in the experimental site of Montech (South of France) (Lefebvre et al 2000) and to some model refuses described in the literature (Borgés 1988;Robles Martinez et al 1997;Vincent 1991 during the biodegradation of this model waste were monitored. In this paper, the experimental data are compared to numerical results given by a model that takes into account the identified biological and physical coupled processes.…”

“…This temperature was chosen from the landfill observation (Lefebvre et al 2000) which showed that the waste located from about 1.5 m depth were in anaerobic conditions and presented a steady temperature that, generally, ranged between 40 and 50°C. During this landfilling, each new layer exchanges heat, both with the atmosphere and with the just-below refuse layer.…”

“…Waste Manage Res 2001: 19: 58-69 Printed in UK -all rights reserved Introduction As shown in the first part of this paper (Lefebvre et al 2000), the initial temperature field inside a landfill mainly results from the aerobic degradation of fresh solid waste. The aim is to better understand the role of biochemical processes on the temperature rise, in relation to landfill management protocols.…”