Removal of landfill leachate toxicity and genotoxicity by two treatment methods

Abstract

Leachates from active and closed municipal solid waste landfills can be a major source of contamination to groundwater and surface waters. In the present study the toxic and genotoxic potential of leachate from an old sanitary landfill prior to and following chemical and electrochemical treatments were assessed using Lemna, Allium, and comet tests. Photosynthetic pigments, malondialdehyde (indicator of lipid peroxidation) and antioxidant enzyme activities were evaluated as additional indicators of toxicity in duckweed. Following duckweed exposure to 25 % dilution of landfill leachate, growth rate and photosynthetic pigments content significantly decreased while lipid peroxidation increased despite stimulation of antioxidative defence mechanisms. Diluted leachate induced DNA strand breaks in duckweed cells as evidenced by the comet assay. Regarding the Allium test, untreated leachate caused inhibition of Allium cepa cell division and induction of mitotic and chromosomal aberrations. Although both water treatments completely reduced genotoxicity of leachate, the electrochemical method was found to be more efficient in removing toxic substances present in landfill leachate and thus more suitable for treating such leachates prior to their discharge into the environment. As landfill leachates pose a risk to human health and environment in general due to their (geno)toxicity, the present study demonstrates that the ecotoxicity/genotoxicity assays should be used in leachate risk assessment together with physicochemical analysis.

Assessment of Denitrification and Nitrification Processes during Landfill Leachate Treatment

“…In practice, a number of examples can be found for the use of enzyme activity as an important indicator for leachate treatment. For example, enzyme activities of phenol hydroxylase, esterase, phthalate dioxygenase, ammonia monooxygenase, peroxidase and catalase were investigated in leachate treatment with activated sludge [21,22]. Laccase activity and manganese-independent and manganese-dependent peroxidase activities were used in other studies related to the treatment of leachate with fungi [23,24].…”

Comparison of Physical and Chemical Composition of Leachate from Three Municipal Waste Landfills: Sarajevo, Zenica and Tuzla (Bosnia and Herzegovina) Case Study

“…dissolved from waste. Therefore, these waters must be collected and treated in a controlled manner and their uncontrolled discharge into surface and groundwater without prior treatment must be prevented (Brkanac et al, 2013). In order to ensure long-term stable collection and continuous, economically viable leachate treatment, it is necessary to establish volume control (filtrate production) and a uniform leachate composition.…”

Combined Treatment of Old Sanitary Landfill Leachate

“…Considering the complex and variable composition of the leachate, its low biodegradability as well as its high toxicity to various test systems (17)(18)(19), a combined treatment approach should be applied to remove toxic pollutants down to the regulated values. In that case, electrochemical methods are combined with advanced oxidation (5) or chemical pretreatment (6) that result in higher removal rates of both COD and ammonium.…”