Operating parameter Training RMSE Checking RMSE Electrolysis time 12.55 11.89 Current density 10.12 11.80 pH 9.97 9.82

Note: Input variable with the least training RMSE is the most relevance with respect to COD removal efficiency.

Table 3: Results from adaptive neuro-fuzzy inference system for selecting the operating parameter that mostly influence the COD removal efficiency.