Physical-chemical treatment of landfill leachate : technological performance, spectral characterization and cost estimations

The generation of landfill leachate is a significant result of landfilling. Because of the high concentrations of pollutants in leachate, disposal of raw or insufficiently treated landfill leachate can cause harm to the environment. Biological processes are inefficient for the treatment of stabilized landfill leachate given the presence of recalcitrant organic compounds and low leachate biodegradability. As such, post-treatment is required to meet discharge standards. Therefore, this PhD thesis focused on the (post)-treatment of raw and biologically treated landfill leachate using four physical-chemical processes, i.e. ozonation, coagulation-flocculation, granular activated carbon (GAC) adsorption, and ion exchange. The aim was obtaining an optimized and cost effective integrated leachate treatment train. The research also used spectral and chemometric techniques to characterize dissolved organic matter (DOM) components in landfill leachate and to monitor how they are removed during treatment. The results show that (post)-treatment of raw and biologically treated leachate with a single physical-chemical step is inefficient as the environmental discharge standards are not met. However, combining coagulation-flocculation or ozonation with GAC adsorption significantly reduces the pollutant concentrations making it possible to meet the discharge standards. Spectral and chemometric analysis show that coagulation as a pre-treatment step removes high molecular weight humic compounds that would otherwise clog the GAC adsorption sites, and that GAC unselectively removes DOM components hereby improving the overall performance. Ion exchange can be used to recover ammonium from the raw landfill leachate with complete removal. Overall, (post)-treatment of raw and biologically treated leachate with coagulation-flocculation + GAC + ion exchange and coagulation-flocculation + GAC, respectively, are shown to be more efficient and cost effective than a treatment train without coagulation-flocculation pre-treatment

Organic matter and nitrogen recovery from landfill leachate using coagulation flocculation followed by granular activated carbon and ion exchange

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Ozonation of landfill leachate: cost effectiveness and insights on conversions of organic matter

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