David Bendz

Water balance for landfills of different age

Water-related processes in landfills are discussed with emphasis on internal processes such as field capacity, moisture variation in time and space, and macropore flow. Runoff production and evaporation from landfills in Sweden of different age are investigated. It is clarified in what ways and for how long a closed municipal landfill differs from an ordinary land area from a hydrological point of view.

Accumulation of water and generation of leachate in a young landfill

Abstract Seven-year-old pilot-scale landfills were investigated with respect to operation of the soil cover, accumulation of water and rainfall-leachate flux relationship. The annual soil moisture fluctuation in the soil cover was of the order of 120 mm. Given an average precipitation of 580 mm, the net water input into the landfill, split into storage and leachate discharge, was on average 250 mm annually. The portion that becomes leachate increased from zero to about half during 6.5 years. The storage increase was about 180 mm/m during this period. Fair agreement between the calculated storage and the moisture content in solid waste samples was observed. A 1–2 month time lag in the net water input-leachate discharge relation was observed. It is suggested that the observed short leachate flux response to a period of infiltration may indicate that a large part of the water is retained by surface tension as thin films in restricted channels, which is overcome by gravity when the input is suddenly increased. The storage-leachate flux relationship was quantified and was found to consist of a family of curves depending on the storage and the rise or decline of leachate flux.

Kinematic wave model for water movement in municipal solid waste

The movement of water in a large (3.5 m(3)) undisturbed sample of 22-year-old municipal solid waste has been modeled using a kinematic wave approximation for unsaturated infiltration and internal drainage. The model employs a two-parameter power expression as macroscopic flux law. The model parameters were determined and interpreted in terms of the internal geometry of the waste medium by fitting the model to one set of infiltration and drainage data. The model was validated using another set of data from a sequence of water input events. The results of the validation show that the model performs satisfactorily, but further development of the model to incorporate spatial variability would increase its capability.

Evaporation from an active, uncovered landfill

Abstract The effect on evaporation of the presence of biodegradation heat in an uncovered biocell under operational conditions is elucidated. The contribution of the heat of biodegradation was investigated by measuring the temperature gradient in the top layer of a landfill. The evaporation was calculated by combining the energy budget with an expression for sensible heat flux, and taking the atmospheric stability into account by introducing the similarity theory of Monin and Obukhov. It was found that the biological heat enhanced the net energy flux and the actual evaporation by 20% and 10%, respectively.

Solute transport under steady and transient conditions in biodegraded municipal solid waste

An edited version of this paper was published by AGU. Copyright 1999 American Geophysical Union.

Acid neutralization capacity of waste - specification of requirement stated in landfill regulations

The EU regulation of landfill aims to the safe disposal of waste in the long term. The regulation requires the collection of information on waste characteristics before landfilling. Acid neutraliza ...

Development of criteria for acceptance of monolithic waste at landfills

A Nordic study has been carried out to develop a methodology for the setting of criteria for acceptance of monolithic waste at landfills in accordance with the requirements in the Council Decision ...