A biological pluridisciplinary model to predict municipal landfill life

The degradation processes occurring within landfills are the keys to assessment and control of their environmental impact. This degradation results from different microbial activities interacting all along the landfill lifetime and influenced by several non-biological factors. Approaching these complex biological and chemical processes requires a multidisciplinary pattern. 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, sulphate concentration in leachates and settlement measures allows to predict landfill age 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. The mathematical model has also been applied, with success, to the case of Anton Sclayn site.