Comparative process optimization of pilot-scale total petroleum hydrocarbon (TPH) degradation by Paspalum scrobiculatum L. Hack using response surface methodology (RSM) and artificial neural networks (ANNs)

The aim of this study is to investigate an optimization process for the degradation of total petroleum hydrocarbon (TPH) by a tropical plant, Paspalum scrobiculatum L. Hack, using response surface methodology and artificial neural network. The optimum conditions predicted by RSM were found to be at a diesel concentration of 3%, 72 sampling days and an aeration rate of 1.77 L/min with a 76.8% maximum TPH removal. The coefficients of determination (R-2) and adjusted R-2 for the RSM model equations were 0.8530 and 0.7208. The optimum conditions predicted by the ANN were found to be at a diesel concentration of 3%, 72 sampling days and an aeration rate of 1.02 L/min with an 85.5% maximum TPH removal. Analysis using the ANN's prediction data, which showed a higher R-2 value of 0.957 and small values of Average Absolute Deviation (AAD) and Root Mean Square Error (RMSE), were 0.33% and 0.302, respectively. Validation analysis showed the predicted values by RSM and ANN were close to the validation values, whereas the ANN showed the lowest deviation, 2.57%, compared to the RSM. This finding suggests that the ANN showed a better prediction and fitting ability compared to the RSM for the non-linear regression analysis. (C) 2016 Elsevier B.V. All rights reserved.