Applying kohonen self-organizing map as a software sensor to predict biochemical oxygen demand

The 5 days at 20°C biochemical oxygen demand (BOD₅) is an important parameter for monitoring organic pollution in water and assessing the biotreatability of wastewater. Moreover, BOD₅ is used for wastewater treatment plant discharge consents and other water pollution control purposes. However, the traditional bioassay method for estimating the BOD₅ involves the incubation of sample water for 5 days. It follows that BOD ₅ is not available for real-time decisionmaking and process control purposes. On the other hand, previous efforts to solve this problem by developing more rapid biosensors had limited success. This paper reports on the development of Kohonen self-organizing map (KSOM)-based software sensors for the rapid prediction of BOD₅. The findings indicate that the KSOM-based BOD₅ estimates were in good agreement with those measured using the conventional bioassay method. This offers significant potential for more timely intervention and cost savings during problem diagnosis in water and wastewater treatment processes.