Evaluation of Fenton Pretreatment and MBBR Reactor Performance for Leachate Biodegradability Improvement
Author
Mosebo, Reena Bausram
Term
4. term
Publication year
2025
Submitted on
2025-06-04
Pages
75
Abstract
Specialet undersøgte, om Fenton-oxidation som forbehandling kan gøre perkolat fra lossepladser mere bionedbrydeligt og dermed forbedre rensningen i en Moving Bed Biofilm Reactor (MBBR), en biologisk proces hvor mikroorganismer vokser på bevægelige bæremedier. Perkolater med forskellige COD-niveauer (kemisk iltforbrug, et mål for organisk forurening) blev først screenet for optimale Fenton-betingelser: surt pH, et Fe2+:H2O2-forhold på 1:5 og 30 minutters reaktionstid. Disse betingelser blev derefter brugt som forbehandling før 24-timers MBBR-forsøg. Fenton-behandlingen gav store COD-reduktioner i denitrifikationsreaktorer - op til 73% for Odense-perkolat og 68% for Aarhus-perkolat. Målinger af OUR (iltoptagelseshastighed), TOC (total organisk kulstof) og OXC indikerede, at de behandlede perkolater allerede var let bionedbrydelige, og inhibitionsanalyser fandt ingen hæmmende stoffer. Samlet pegede dette på karakteristika for unge perkolater, hvor en stor del af de organiske stoffer er let nedbrydelige. Det tyder på, at Fenton primært fjernede allerede letnedbrydelige organiske forbindelser i stedet for at omdanne svært nedbrydelige stoffer til mere tilgængelige former. Overordnet viste MBBR'en god ydeevne med både ammoniumoxidation og yderligere COD-reduktion.
The thesis examined whether Fenton oxidation can be used as a pretreatment to make landfill leachate more biodegradable and thereby improve treatment in a Moving Bed Biofilm Reactor (MBBR), a biofilm-based process where microorganisms grow on moving carriers. Leachates with different COD levels (chemical oxygen demand, a measure of organic pollution) were first screened to identify optimal Fenton conditions: acidic pH, an Fe2+:H2O2 ratio of 1:5, and a 30-minute reaction time. These conditions were then applied before 24-hour MBBR experiments. Fenton treatment led to large COD reductions in denitrification reactors - up to 73% for Odense leachate and 68% for Aarhus leachate. Measurements of OUR (oxygen uptake rate), TOC (total organic carbon), and OXC indicated that the treated leachates were already highly biodegradable, and inhibition tests detected no inhibitory components. Together, these findings are consistent with characteristics of young leachates, in which many organics are readily degradable. This suggests that Fenton mainly removed already easily degradable organics rather than converting refractory compounds into more bioavailable forms. Overall, the MBBR performed well, achieving ammonium oxidation and additional COD reduction.
[This summary has been rewritten with the help of AI based on the project's original abstract]
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