Optimization of chitosan flocculation for microalgal-bacterial biomass harvesting via response surface methodology

The purpose of this study was the evaluation of chitosan flocculation ability to recover microalgal-bacterial biomass from an open pond treating fish processing wastewater. A second order factorial design followed by response surface methodology was applied to estimate the effect of chitosan concentration and agitation speed on flocculation activity. Second-order polynomial model fitted quite well with the experimental results. Chitosan concentration exhibited a higher effect on the flocculation process than agitation speed. The highest flocculation efficiency (92%) was obtained at a concentration of 214 mg L−1 and an agitation speed of 131 rpm.

► Chitosan flocculation for removing biomass from an open pond was evaluated.
► A second order factorial design followed by response surface methodology was applied.
► Second-order polynomial model fitted quite well with the experimental results.
► Chitosan concentration exhibited a higher influence than agitation speed.