An Efficient Biological Treatment on Dairy Wastewater by Lactobacillus plantarum: Mathematical Modeling and Process Parameters Optimization

Abstract

Abstract The ability of Lactobacillus plantarum for biological treatment of dairy wastewater was investigated using a response surface method. The effects of three culture condition parameters of temperature (24.93–40.07°C), pH (4.3–6.7), and agitation rate (99.5–200.5 rpm) on the removal efficiency of sugar, total protein content (TPC), and chemical oxygen demand (COD) of the wastewater were studied. For each response parameter, a second-order polynomial model versus independent variables (p < 0.0001) was determined and statistically obtained with high coefficient of determination values (R2 > 0.95). Numerical optimization defined the optimum treatment conditions for achieving the highest removal efficiency was temperature of 28°C, pH of 5.03, and agitation rate of 147.51 rpm. Under the optimum condition, the removal efficiency values for sugar, TPC, and COD were predicted to be 72.18%, 54.51%, and 78.99%, respectively.