Predicting COD removal efficiency from wastewater using photoelectrocatalytic process

This paper presents development of generalised equations for predicting chemical oxygen demand (COD) removal efficiency from wastewater through a photo-electro catalysis process based on experimental measures conducted earlier. From series of experimental measurements involving three contributing factors (time, voltage and pH), two were selected for the formulation as the third one (voltage) was kept constant at 2.5 V, which yielded the highest removal efficiency. Seven individual equations of time-varying COD removals were developed for the seven different pH values (3–9). It is found that the coefficients/constants of the developed equations can be correlated with corresponding pH values, rendering a single generalised equation which is capable to predict COD removal at any time under any pH. Predictions from the developed equations were compared with the mentioned experimental measurements. It is found that the developed equation is capable to accurately predict potential COD removal efficiency having a correlation coefficient of 0.99 with the measured data. Standard errors of the equation’s estimations are also quite low, having RMSE = 4.82, MAE = 3.97 and RAE = 0.10. Such mathematical frameworks are expected to assist decision makers on deciding optimum input parameters in removing COD through the mentioned photo-electro catalysis process from municipal wastewater.