Optimization of textile effluent bacterial treatment and improvement of the process efficiency through SPB1 biosurfactant addition

Abstract

The current work aims to optimize biological textile effluent treatment through the use of newly selected bacterial consortia composed of two strains: Citrobacter sedlakii RI11 and Aeromonas veronii GRI. We assessed the effect of SPB1 biosurfactant addition on color removal (CR). The process was optimized by a Box–Bhenken by examining the effect of pH, consortia density and biosurfactant value on treatment efficiency. Firstly, physicochemical analyses of the studied effluent revealed an alkaline pH along with a high content of suspended materials and large amounts of organic matter. Optimal CR and a chemical oxygen demand abatement of about 94 and 86% were obtained when treating the textile effluent at pH 5 with a total optical density of 0.4 and by incorporating 0.01% SPB1 biosurfactant. Additionally, an abolishment of phytotoxicity was registered after treatment optimization. The evaluations of the action mode of both selected bacteria during textile effluent treatment suggested the occurrence of biodegradation phenomena of dyes through enzymatic activities. HIGHLIGHTS Bacterial textile effluent treatment.; Optimization of the treatment by Box–Bhenken design and response surface methodology.; Optimal treatment by the increase of color removal and the abatement of chemical oxygen demand.; Enhancement of the treatment by SPB1 biosurfactant addition.;

Keywords

• biodecolorization
• box–bhenken
• cod decrease
• response surface methodology
• textile effluent