Improvement of the activated sludge treatment by its combination with electro Fenton for the mineralization of sulfamethazine

Dorsaf Mansour (1) , Florence Fourcade (1) , Samuel Huguet (1) , Isabelle Soutrel (1) , Nizar Bellakhal (2, 3) , Mohamed Dachraoui (2, 3) , Didier Hauchard (1) , Abdeltif Amrane (1)

1 ISCR - Institut des Sciences Chimiques de Rennes
2 INSAT - Institut National des Sciences Appliquées et de Technologie [Tunis]
3 Laboratoire de Chimie Analytique et Electrochimie

A combined process coupling an electro-Fenton pretreatment and a biological degradation in order to mineralize sulfamethazine (SMT) was investigated. The electro-Fenton pretreatment of SMT was first examined and the intermediates products were identified for an initial SMT amount of 0.36 mM, after 1 h electrolysis at pH 3, 18 °C, 200 mA. 94.2% SMT was degraded but the level of mineralization remained low (6.5%), ensuring significant residual organic content for a subsequent biological treatment. Two possible degradation reaction pathways involving all the identified and quantified intermediates are proposed. In a second part, biological treatments with fresh activated sludge were performed to complete the mineralization of the electrolyzed solution of SMT, showing an increase of the mineralization yield with time duration of the pretreatment. For an initial SMT concentration of 0.2 mM, a ferrous ions concentration of 0.5 mM, at pH 3, 18 °C and 500 mA, the mineralization yield during the biological treatment increased as follows: 61.4, 78.8 and 93.9% for 0.5, 1 and 4 h pretreatment, confirming the relevance of the proposed combined process.

Mots clés: Activated sludge; Combined process; Degradation pathway; Drug removal; Electro-Fenton; Sulfatmethazine

Domaines: Chimie inorganique

Dorsaf Mansour, Florence Fourcade, Samuel Huguet, Isabelle Soutrel, Nizar Bellakhal, et al.. Improvement of the activated sludge treatment by its combination with electro Fenton for the mineralization of sulfamethazine. International Biodeterioration and Biodegradation, 2013, 88, pp.29-36. ⟨10.1016/j.ibiod.2013.11.016⟩. ⟨hal-00991476⟩