A pluridisciplinary model to predict municipal landfill life

Most degradation processes that occur within municipal wastes landfills result from different microbial activities interacting all along the landfill lifetime and that are influenced by several non-biological factors. These complex biological and chemical processes require a multidisciplinary pattern in order to assess and control their environmental impact. Thanks to Walloon Region support, we have developed a pattern or model combining the evolution of different key parameters. Such parameters qualify biogas (composition, production rate), leachate (pH, BOD5, COD, volatile fatty acids, redox potential, nitrogen balance, humic acids...), or solid waste (moisture, settlement, cellulose content...). This paper presents relationships, including our model, between these parameters. Variations of pH, BOD5/COD ratio, sulfate concentration in leachates, gas composition analysis and settlement measures allow to predict landfill age, on a standard scale, since completion. Evaluation of cellulose and water content in refuse as well as settlement degree are useful to estimate the time required for complete biological degradation.