Removal of the Recalcitrant Artificial Sweetener Sucralose and Its By-Products from Industrial Wastewater Using Microbial Reduction/Oxidation of Iron

Abstract

The wastewater of the industrial production of artificial sweetener sucralose contained an average 1100 mg/L of total organic carbon (TOC) with 2100 mg/L of chemical oxygen demand and 10 mg/L of biological oxygen demand. Biodegradability of the wastewater components was low due to chlorinated organic substances. The combined chemical and biological treatment of this wastewater in the bioreactors with hematite iron ore removed up to 70% of TOC. About 20% of TOC was removed quickly by adsorption on iron ore particles, but adsorption/precipitation of others up to 50% of TOC was due to ferrous/ferric ions and hydroxides produced during microbial reduction and dissolution of iron ore. The calculated dosage of iron ore with 150 regeneration cycles could be 46.7 g/L of wastewater. Thus, the treatment of wastewater with iron ore and iron-reducing bacteria diminished the quantity of granulated activated carbon that is used in the treatment of sucralose production wastewater by up to 70%.