Bioaugmentation with Advenella kashmirensis for the treatment of a kraft pulp effluent by aerated lagoon

Abstract

Brazil is considered a world leader in paper production. It is estimated that the sector contributes 46.5% of the national gross domestic product, and its effluents have high concentrations of organic matter and recalcitrant compounds which can cause coloration and ecotoxicity, generating impact if not properly treated. A potential strategy for the treatment of this wastewater is bioaugmentation with native bacteria isolated from the industrial sludge and effluent, which, due to their potential metabolism adapted to adverse environmental conditions, may favor the removal of specific compounds. When associated with immobilization techniques, the inoculum can develop as a biofilm adhered to a support medium, which provides surfaces for adhesion, growth and survival of bacteria. We therefore investigated the treatment of Kraft pulp effluent by bioaugmentation with the autochthonous bacterium Advenella kashmirensis both immobilized in a spongy support medium - Aqua Porous Gel (APG) - and in free-swimming (planktonic) form, denominated Phase I and II, respectively. The investigation was performed in a bench-scale aerated lagoon system with untreated industrial effluent. The effect of the use of bacteria in bioaugmentation was assessed by the removal parameters of Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD₅), Color, Total Phenolic Compounds (TPC) and Lignin Compounds (LC). The results indicate that both Phases I and II were efficient for the treatment of COD, BOD₅ and color parameters. However, the biofilm form provided better stability to the biological system in the treatment of the Kraft pulp effluent.

Keywords: adhered, kraft effluent, SEM, suspended solids.