title: Linking landfill hydrology and leachate chemical composition at a controlled municipal landfill (Kåstrup, Denmark) using state-space analysis.
abstract: Leachate production and composition data for a municipal landfill measured over a 25-year period was used to investigate important processes and parameters. Long-term leachate production could be satisfactorily predicted from a simple top-layer landfill hydrology model while short-term predictions were less accurate, likely due to water storage in the waste. State-space and multiple regression modelling were used to identify relations between different parameters. State-space models proved most accurate in fitting measured data, likely because temporal correlation between measurements is accounted for unlike multiple regression. State-space modelling showed that temporal correlation in leachate production must be taken into account and confirmed that water storage inside the landfill is important. Temporal correlation is also important when predicting pH and chloride concentrations but less so for BOD5 and NH3/NH4+concentrations. Leachate flow did in general not have a strong impact upon leachate composition, small effects were observed for Cl-, and NH3/NH4+ concentrations. It was also observed that the mass load of nitrogen from the landfill was strongly dependent upon leachate nitrogen (ammonia/ammonium) concentrations and to a lesser degree upon leachate flow rates. This study introduces state-space modelling in solid waste management as a powerful tool to identify governing parameters for hydrological and bio-chemical processes.
authors.affiliation: Dept. of Environmental Engineering, Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark. tjalfep@hotmail.com
authors.forename: Tjalfe G
authors.initials: TG
authors.lastname: Poulsen
authors.forename: Per
authors.initials: P
authors.lastname: Moldrup
authors.forename: Kirsten
authors.initials: K
authors.lastname: Sørensen
authors.forename: Jens Aa
authors.initials: JA
authors.lastname: Hansen
mesh_terms: D005160:Facility Design and Construction; D006863:Hydrogen-Ion Concentration; D008962:Models, Theoretical; D009584:Nitrogen / Q000032:analysis; D010100:Oxygen / Q000032:analysis; D012037:Refuse Disposal / Q000379:methods*; D012989:Soil Pollutants / Q000032:analysis*; D014872:Water Movements; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D012989:Soil Pollutants; D014873:Water Pollutants; D009584:Nitrogen; D010100:Oxygen