Eletrólise de resíduos poluidores: I - Efluente de uma indústria liofilizadora de condimentos

Abstract

Wastewater from a seasoning freeze-drying industry was electrolysed to increase its biodegradability. Stainless-steel electrodes were used at 9.09 A/m2, for up to 80 min. Conductivity, pH, biochemical (BOD) and chemical (COD) oxygen demands, Daph-nia similis acute toxicity bioassays, and bacteria counting through the plate count agar method were determined after different times of electrolysis. The results (e.g. higher BOD and lower COD) showed that the biodegradability of the wastewater was significantly increased; furthermore, Fe2+ ions liberated by the electrodes cause microorganisms to die and, when oxidised to Fe3+, contribute for the flocculation and sedimentation of solid residues.