Several advanced technologies – solar heterogeneous photocatalysis with TiO2, solar photo-Fenton, and ozonation – are studied as tertiary treatments for the remediation of micropollutants present in real municipal wastewater treatment plant (MWTP) effluents at pilot plant scale. Solar photo-Fenton is a promising tertiary treatment for MWTP effluents, whose investment cost is offset by the operating cost of ozonation.
Conventional municipal wastewater treatment plants are not able to entirely degrade some organic pollutants, that end up in the environment. Within this group of contaminants, 'emerging contaminants' are mostly unregulated compounds that may be candidates for future regulation.
In this Spanish work, different advanced technologies – solar heterogeneous photocatalysis with TiO2, solar photo-Fenton, and ozonation – are studied as tertiary treatments for the remediation of micropollutants present in real municipal wastewater treatment plants effluents at pilot plant scale.
Contaminants elimination was followed by liquid chromatography/quadrupole ion trap mass spectrometry (LC-MS) analysis after a 100:1 pre-concentration by automatic solid phase extraction. In this work 66 target micropollutants were identified and quantified; 16 of those contaminants at initial concentrations over 1000 ng/L made up over 88% of the initial total effluent pollutant load.
The order of micropollutants elimination efficiency under the experimental conditions evaluated was: solar photo-Fenton > ozonation > solar heterogeneous photocatalysis with TiO2.
Toxicity analysis using Vibrio fischeri and respirometric tests showed no significant changes in the effluent toxicity after application of the three tertiary treatments. Solar photo-Fenton and ozonation treatments were also compared from an economical point of view.
