Incorporation of ozone-driven processes in a treatment line for a leachate from a hazardous industrial waste landfill: Impact on the bio-refractory character and dissolved organic matter distribution

The current work aimed to evaluate the feasibility of including ozone (O3)-based advanced oxidation processes (AOPs), as an intermediate step, in a multistage treatment system for non-biodegradable sulphur-rich leachate from hazardous industrial solid waste landfill (HISWL), combining chemical and biological technologies. O3-based AOPs covered perozonation (O3/H2O2), photo-assisted ozonation (O3/UVC), (O3/H2O2/UVC). All O3-driven were applied HISWL directly after sulphur compounds removal via catalytic precipitation. Moreover, was also tested sequential coagulation step using ferric or aluminium salts (O3/Fe2+ O3/Al3+), O3/H2O2/UVC likewise tried Fe-mediated targeting photo-Fenton-assisted (O3/PF). best-performing train encompassed: (i) with H2O2 (stoichiometric amount) under free pH, convert sulphite sulphide ions into oxidised species, sulphate; (ii) precipitation sulphate barite mineral without pH correction; (iii) O3/H2O2 process ca. 2.1-h (natural pH; room temperature; 3.5 kg O3 1.1 per m3 leachate), degrade refractory organic matter improve biodegradability; (iv) remove remaining bioavailable organics fraction. This four-stage approach allowed shifting highly recalcitrant wastewater effluent full agreement regulation discharge municipal sewer network. Furthermore, effectiveness over dissolved transformation corroborated by fluorescence excitation-emission matrix size exclusion chromatography analysis.