Characterisation of Hazardous Waste Landfill Leachate and its Reliance on Landfill Age and Seasonal Variation: A Statistical Approach

Abstract

Leachate generated due to disposal industrial solid waste into common hazardous waste landfills (HWLs), has high potential to contaminate nearby soil and groundwater and hence its catchment and treatment are crucial for sustainable solid waste management. This research is emphasised on creating an extensive data set generated from analysing three hazardous waste landfills of age 2-year, 11-year and 20-year for a duration of one year to characterise the leachate and to create an in-depth understanding about the effect of landfill age and seasonal variation on leachate characteristics. Results in the form of descriptive statistics showed the simultaneous occurrence of high chemical oxygen demand (COD) (up to 35,000 mg/l) and high concentration of total dissolved solids (TDS) (up to 3,00,000 mg/l), ammoniacal nitrogen (up to 2300 mg/l) and heavy metals. Statistical analysis through ANOVA and Post Hoc analysis indicated that the age of landfill significantly affects the leachate characteristics and for most of the parameters, the concentrations were found to increase till middle age and then subside towards maturity of landfill. In contrast to this, for seasonal variation, less significant influence was observed on the leachate characteristics. Although the concentration of different parameters was found to vary every month, no specific pattern or effect on seasonal variation could be traced from the data.