Differences in the Composition of Leachate from Active and Non-Operational Municipal Waste Landfills in Poland

Abstract

Leachate formation is one of the many environmental hazards associated with landfilling. The leachate may migrate from the landfill to surface water and groundwater, posing a potential threat to aquatic ecosystems. Moreover, its harmful effect on human health and life has been proven. Due to the risks that landfill leachates may pose, it is necessary to control the state of the environment in their surroundings. The paper presents an example of the application of selected statistical methods (basic statistics, statistical tests, principal component analysis) to assess the impact of individual pollution indicators on the quality of landfill leachates. The conducted analysis showed the existence of significant differences between the surveyed active (Legnica, Jawor) and non-operational (Wrocław, Bielawa) landfills in Poland. These differences were especially visible in the cases of the following: electric conductivity (EC) (non-operational landfills 1915–5075 μS/cm, active 5093–11,370 μS/cm), concentrations of total Kjeldahl nitrogen (TKN) (non-operational landfills 0.18–294.5 mg N/dm3, active 167.56–907.4 mg N/dm3), chemical oxygen demand (COD), organic nitrogen (ON), ammonium nitrogen (AN), total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), sulfates, chlorides, sodium, potassium, calcium, magnesium and nickel. Selected indicators should help to determine the progress of decomposition processes inside the landfill and the potential impact of leachate on the environment, and should be used in the mandatory monitoring of landfills.