Modernizing CSO Notification and Forecasting with Digital Tools

The prevention, mitigation, and management of combined sewer overflows (CSO) continues to be a focal point for municipal wastewater utilities throughout the country. Regulatory requirements are constantly evolving and continue to increase emphasis on public alerting. Modern digital solutions can be used to improve the way that utilities notify the public about the occurrence and effect of CSOs in their communities. This presentation will provide examples of enhanced CSO prediction and notification tools that leverage predictive analytics and machine learning to improve transparency in CSO management. In the first example, an alert system was developed to inform community members of the risk of high bacteria levels downstream from CSOs. The alert tool uses publicly available information that is fed into an algorithm developed with historic data and relationships, including time of travel and decay constants, specific to the river. The tool has been validated against several overflow events and predicts downstream bacteria concentrations within a reasonable and useful accuracy. The results of the predictive tool are available on a public website hosted by the regional planning agency. Innovative tools that leverage existing engineering information are effective at informing the public about the real-time contamination risks of combined sewer overflows. The second example demonstrates how surrogate modeling using machine learning can predict collection system flows, and associated CSOs, in real time. This example also maximizes the use of existing available data and information to create a modern prediction tool. A calibrated hydraulic model of a combined collection system was used to train a machine learning model to produce predictive flows based on real-time weather forecasts. The knowledge of when, where, and how much combined sewage is predicted to be released into local waterways can be used to alert the public of impending closures and advisories. This type of tool can also be used by utility managers and operators to plan for upcoming overflows and increased inflow to wastewater treatment facilities.