AI-driven modelling approaches for predicting oxygen levels in aquatic environments

Abstract

Reliable water quality models are crucial for better water management and pollution control. Biochemical oxygen demand (BOD) and dissolved oxygen (DO) are the widely recognized indicators used to examine the quality of water. Stakeholders often face challenges when it comes to monitoring water quality indicators daily. The conventional approach for testing is laborious and costly. Therefore, there is a need to incorporate alternate concepts for predicting water quality parameters. This article proposes a novel approach “Autoencoder-Deep-Autoregressive (AE-DeepAR)” to predict the concentration of BOD and DO using in-situ measurable water quality parameters as input. The autoencoder is employed to utilize a latent space that accurately captures the fundamental characteristics of the nonlinear data. On the other hand, the DeepAR model is utilized to produce point predictions. This approach is being implemented in the Mahanadi River system for the first time. It is found that conductivity, total suspended solids (TSS), turbidity, and ammoniacal nitrogen (NH3-N) are correlated with BOD. Likewise, turbidity, temperature, and total dissolved solids (TDS) correlate significantly with DO. The performance of the AE-DeepAR model in predicting BOD surpasses that of other models at all stations. The R2 range from 0.90 to 0.93, mean absolute error (MAE) varies from 0.061 to 0.147, mean squared error (MSE) lies between 0.005 to 0.028, and mean absolute percentage error (MAPE) differs from 9.20% to 19.95%. All stations show a greater degree of sensitivity. The uncertainty observed is less in most circumstances, but the unpredictability of the values caused by the occurrence of outliers in severe events may influence the outcome. The PICP value varies between 87 % to 95 % in BOD and 89 % to 95 % in DO. The results reveal that AE-DeepAR can be used as an alternative approach to predict BOD and DO with a high degree of accuracy.