Modelling the biological treatment process aeration efficiency: application of the artificial neural network algorithm

Abstract

The biological treatment process (BTP) is responsible for removing chemical oxygen demand (COD) and ammonia using microorganisms present in wastewater. The BTP consumes large quantities of energy due to the transfer of oxygen using air pumps/blowers. Energy consumption in the BTP is due to low solubility of oxygen, which results in low aeration efficiency (AE). The aim of the study was to develop an AE model that can be used to monitor the performance of the BTP. Multilayer perceptron artificial neural network (MLP ANN) algorithm was used to model AE in the BTP. The performance of the AE model was evaluated using R2, mean square error (MSE), and root mean square error (RMSE). Sensitivity analysis was performed on the AE model to determine variables that drive AE. The results of the study showed that MLP ANN algorithm was able to model AE. R2, MSE, and RMSE results were 0.939, 0.0025, and 0.05, respectively, during testing phase. Sensitivity analysis results showed that temperature (34.6%), COD (21%), airflow rate (19.1%), and OTR/KLa (15.7%) drive AE. At high temperatures, the viscosity of wastewater is low which enables oxygen to penetrate the wastewater, resulting in high AE. The AE model can be used to predict the performance of the BTP, which will assist in minimizing energy consumption. HIGHLIGHTS Aeration efficiency increases with an increase in temperature.; Aeration efficiency decreases with an increase in airflow rate.; Temperature and airflow rate are the biggest driver of energy consumption.; Temperature, COD, and airflow rate control aeration efficiency in the biological treatment process.; High temperatures and airflow rates improve volumetric mass transfer coefficient.;

Keywords

• aeration efficiency
• airflow rate
• cod concentration
• oxygen uptake rate
• temperature
• volumetric mass transfer coefficient