Removal of 17α-ethinylestradiol and caffeine from wastewater by UASB-Fenton coupled system

ABSTRACT

In aquatic systems, some substances considered as endocrine disruptors have been detected, which can be due to their incomplete elimination in wastewater treatment plants (WWTPs) and inadequate disposal of pharmaceuticals. Among these contaminants are 17α-ethinylestradiol (EE2) and caffeine (CAF). Moreover, it has been reported that this kind of contaminants may provoke different adverse effects in many aquatic organisms. Because of that, in the present study, up-flow anaerobic sludge blanket reactors (UASB) coupled with the Fenton process was evaluated for EE2 and CAF removal spiked in wastewater samples. First, the best reaction conditions were established in each process. For UASB reactor, two hydraulic retention times (HRT 8 and 24 h) were evaluated, achieving the highest chemical organic demand (COD) removal (70 %) and drug elimination (84 %–86 %) with HRT 24 h. Subsequently, Fenton process was conducted at pH 3 with different levels of Fe²⁺ (0.05–0.5 mmol/L) and molar ratios Fe²⁺:H₂O₂ (1:1–1:10). Better results were obtained with 0.5 mmol Fe²⁺/L, and 1:10 ratio molar Fe²⁺:H₂O₂. Finally, UASB-Fenton coupled system allowed 80 % of COD decrease, almost complete removal of drugs and the toxicity of samples on Vibrio fischeri was reduced from 73 % to 30 %, demonstrating that this coupled system is a promising and efficient system for pharmaceutical compounds removal from wastewater.

GRAPHICAL ABSTRACT

KEYWORDS:

• Advanced oxidation processes
• anaerobic reactor
• endocrine disruptor
• estrogenic compounds
• psychoactive substance

Acknowledgements

The first author thanks El Colegio de la Frontera Sur (ECOSUR) and Consejo Nacional de Ciencia y Tecnología (CONACYT) for financial support (CVU/grantee number: 736037/595291). Special thanks to MSc. Ricardo Castro Chan and Miss Sandra Luz Matías Castillo for their invaluable support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

Khirbet López-Velázquez http://orcid.org/0000-0002-1794-8557

Minerva Villanueva-Rodríguez http://orcid.org/0000-0001-7481-2499

David Herrera-López http://orcid.org/0000-0002-9259-332X

Additional information

Funding

This work was supported by Consejo Nacional de Ciencia y Tecnología (CONACYT): [grantee number: 736037/595291].