Does micropollutant removal by solar photo‐Fenton reduce ecotoxicity in municipal wastewater? A comprehensive study at pilot scale open reactors

BACKGROUND The reduction of toxicity in secondary effluents by solar photo‐Fenton has not been widely studied. In this present work, a strategy combining monitoring of micropollutants and application of a selected battery of bioassays has been applied to evaluate the effectiveness of the solar photo‐Fenton process for secondary effluent treatment at neutral pH in a raceway pond reactor (RPR) following two operating strategies: sequential iron dosage and the use of Fe(III)–EDDS complex at pilot plant scale. The applied battery of bioassays comprises in vivo (algal growth inhibition test) and in vitro, endocrine disruptor tests (androgenic/glucocorticoid activity and estrogenicity) and cytotoxicity tests. RESULTS The results obtained revealed high efficiency of micropollutant removal (>99%) by both strategies assayed. Regarding toxicity, androgenic/glucocorticoid activity and estrogenicity were efficiently removed in a similar fashion, and the relatively low potential phytotoxicity and cytotoxicity was also attenuated. Both RPR strategies are able to enhance the quality of municipal effluents from chemical and toxicological points of view. CONCLUSION To enable water reuse, the feasibility of solar photo‐Fenton reaction at neutral pH in open reactors for ecotoxicity and micropollutant removal in secondary municipal wastewater has been demonstrated for the first time. © 2017 Society of Chemical Industry