Optimization of nutrients removal from synthetic greywater by low-cost activated carbon: application of Taguchi method and response surface methodology

Abstract

This study considered the experimental parameters (zinc chloride, impregnation ratio and activation times) for nutrients removals (nitrate and phosphate) in synthetic greywater using activated carbon from banana trunk via Taguchi and response surface methodology (RSM). Lastly, the best optimization method was selected to optimize the experimental parameters for nutrient removal in synthetic greywater. For Taguchi method, the most influential experimental parameter was zinc chloride (ZnCl2), followed by impregnation ratio and activation time for both nitrate and phosphate removals. ANOVA results in Taguchi method found that ZnCl2, impregnation ratio, and activation time were significantly associated with phosphate removal. Only ZnCl2 and impregnation ratio were significantly associated with nitrate removal. Response Surface Methodology (RSM) adopting Box–Behnken Design findings indicated that ZnCl2 and impregnation time were the significant experimental parameters for nitrate removal. While, ZnCl2, impregnation ratio and activation time were significantly associated with phosphate removal in synthetic greywater. Three-dimensional surface plots illustrated that the nutrients removals (nitrate and phosphate) increase with the increasing of experimental parameters (ZnCl2, activation time, and impregnation ratio). The RSM method via Box–Behnken Design was chosen as it considered possible linear and non-linear combination interactions between two or more parameters with low errors.