Ph. D. Nicolas THEVENIN

Optimization of a biodegradation process for agricultural effluents composed of mixed pesticides

Thesis directed and supervised by:

• Mr. BERTSCH Christophe University Professor, UHA Colmar
• Mrs. JEZEQUEL Karine, co-supervisor Lecturer UHA Colmar
• Mr. LOLLIER Marc, co-supervisor Lecturer UHA Colmar
• Mrs. NASSER Najat, co-supervisor Dr. RITTMO Agroenvironnement Colmar

Defended on July 11, 2016, in Mulhouse.

Abstract

Aim of this work was to treat effluents obtained from rinsing pesticide (PF) spraying equipment by developing biological treatment process into bioreactor with selected mixed bacterial culture and adsorption support consisting of crushed corn cobs. First, a model PF mixture was designed to represent agricultural effluents at watershed scale. This mixture was composed by 6 herbicides, 3 fungicides and 1 insecticide. Then, inoculum production under PF pressure was developed and sorption properties of corn cobs were investigated. Process parameters were defined at small-scale laboratory and validated into bioreactors. Thus, developed process was a 28 days sequential batch reactor treatment, which reduced more than 50% of molecules weight of model mixture. Despite of this process significantly reduced treated effluents PF contents, remaining phytotoxicity due to herbicide residues failed validation of their post-treatment on a bed planted with reeds.