Determination of Hazardous Fractions in Tannery Landfill Leachate
Land-filling is widely accepted and used in many waste management strategies, but it can constitute hazard for the environment. A study was conducted to evaluate the environmental hazard of a leachate flowing into surface waters without adequate treatment. The investigated leachate has been formed at an industrial landfill, where non-hazardous wastes from all phases of tanning processes including wastewater treatment were disposed. Collected leachate was characterised in terms of biodegradable (as reflected by its average BOD5 value 420-600 mg?L-1) and recalcitrant fractions (average COD was 1200-3400 mg?L-1). To set up a satisfactory treatment method for removal of pollutants from the leachate different toxicity reduction methods were employed to identify groups of substances most hazardous to the environment. We have used filtration, air stripping, adsorption on activated carbon, coagulation-flocculation processes and advanced oxidation with Fe2+/H2O2. It has been estimated that an effective treatment of the leachate could be achieved by the removal of persistent organic fractions and ammonium to avoid broad contamination of surface and groundwater; and this will minimise its serious risk to ecosystems and human health if the chemicals from the leachate migrate to drinking water catchments areas.