Monitoring the performance of wastewater treatment plants for organic matter removal using excitation-emission matrix fluorescence

EEM Fluorescence spectra of an industrial park wastewater and removal percentages for the main EEMF peaks throug the treatment sequence in a WWTP. [Display omitted] •The main fluorescence in the industrial park wastewater corresponds to protein-like peaks.•The highest total removals in industrial WWTPs are achieved for protein-like peaks.•Protein-like peaks show the highest biodegradability in WWTP.•The food industry wastewater shows the greatest diversity of fluorescence peaks.•The only fluorescence in the urban landfill leachate corresponds to humic-like substances. This study has assessed the usefulness of excitation-emission matrix fluorescence (EEMF) as a fast and simple analytical technique to track changes in dissolved organic matter (DOM) during the sequence of treatment in wastewater treatment plants (WWTPs). Three different industrial wastewaters and treatment plants have been studied in this work: an industrial park wastewater treated in an independent line at the Burgos WWTP (Spain), a food industry wastewater (crisps and snacks manufacturing) that was treated in a MBR (Membrane Biological Reactor) pilot plant (University of Burgos) and a municipal landfill leachate treated in a physicochemical treatment plant within the same landfill. Removal percentages for the wastewater organic matter at each stage of the treatment plants were successfully obtained by monitoring the main fluorescence peaks: protein-like peaks (tryptophan-like peaks T1, T2 and tyrosine-like peaks B1, B2), humic-like peaks (fulvic-like peak A and humic-like peak C) and microbially-derived peak M. Therefore, EEMF readily allows the assessment of the reactivity of the different types of organic matter towards specific treatments, such as clarification, biodegradation, filtration, etc. Among the wastewaters studied, the food industry wastewater exhibited the greater diversity of fluorescence peaks (B1, B2, T1, T2, A1, A2 and M) whereas the landfill leachate only showed the presence of humic substances (mainly humic-like peak C). This study has demonstrated that EEMF is a useful and user-friendly technique to monitor the performance of wastewater treatment plants for organic matter removal, allowing a rapid response to potential problems in the treatment.