Thirty contaminants of emerging concern identified in secondary treated hospital wastewater and their removal by solar Fenton (like) and sulphate radicals-based advanced oxidation processes

Thirty contaminants of emerging concern (CECs) were identified and quantified in hospital wastewater (HWW) by LC-MS and their removal by solar photo Fenton (SPF) with ethylenediamine-N,N'-disuccinic acid (EDDS) at spontaneous pH (7.5) was compared to other solar driven advanced oxidation processes (AOPs) (namely, sunlight/persoxydisulphate (SPD) and sunlight/H2O2 (SHP)). Almost all the detected CECs (28) are pharmaceuticals and belong to 13 different classes, with concentrations varied between 0.08 mu g/L (psychiatric drug) to 38.92 mu g/L (antidiabetic). First, the formation of iron-EDDS complexes was characterized by electrochemical methods to compare Fe2+ and Fe3+ behavior. The effect on a carbamazepine (CBZ) aqueous solution of solar driven Fe2+/EDDS and Fe3+/EDDS Fenton processes was comparatively evaluated to select the most effective one for advanced oxidation tests on real HWW and sunlight/Fe2+ -EDDS/H2O2 was the most effective one with 48% removal after 12.5 kJ/L-1 (78% total removal, 30% being under dark Fenton condition). SPF process was also more effective than SPD and SHP (60 mM sunlight exposure, 5 kJ/L-1). Subsequently, the effect of the solar AOPs (SPF, Fe2+ 0.1 mM, EDDS 0.2 Mm, H2O2 2.7 Mm; SPD, PD 1.48 mM; SHP, H2O2 2.7 Mm; 60 min sunlight exposure) was investigated in the treatment of the HWW and SPF resulted the most effective one, all CECs being removed from 70% to 100%.

Automated summary

By comparing the efficiency of different solar-driven advanced oxidation processes, this study found that solar photo Fenton (SPF) with Fe2+-EDDS/H2O2 was the most effective in removing emerging contaminants from hospital wastewater, achieving removal rates ranging from 70% to 100%.