Current methods of monitoring combined sewer overflows (CSOs) in most municipalities still include chalk lines in troughs and blocks of wood set on walls to identify, by their presence or absence, if an overflow has occurred. These methods require frequent, dangerous and costly inspections of all outfalls, and they provide no insight into when the overflow occurred, except that it took place between recorded dispatches to that outfall.
Although the distinction between wet and dry weather CSOs is critical, it is usually an educated guess with traditional CSO monitoring methods as to whether the overflow was a dry weather overflow event or a wet weather overflow event, as there are no accurate methods for determining this.
No more guesswork
A web-based tool that provides real-time, historical and trending information on wastewater collection systems provides a solution. With IntelliServe, from ADS Environmental Services, all overflow events are time-stamped and automatically compared with rain-gauge information to identify the nature, duration and quantity of the overflow.
Additionally, the use of IntelliServe eliminates the labor intensive and dangerous physical inspections of the overflow facilities that can often take place outside of normal working hours. Remote alarm escalation is used to notify operators of potential overflows, and determinations can be made as to the urgency of the event and the need for inspection.
IntelliServe has been deployed into many communities throughout the country for CSO, including Springfield, Mass. This real-time alarm-management system is the primary component of a ten-year contract, managed by United Water for the Springfield Water and Sewer Commission (SWSC), to provide wastewater flow monitoring, CSO alarm services and discharge quantification. United Water chose IntelliServe and ADS for this project based on a mandate for the collection system to work as specified by the SWSC regulatory compliance.
Reactive to proactive
There was a need for dry weather CSO alarming data and more accurate reporting information. ADS provided United Water with a turnkey system that was customized to its requirements and included a monitoring network of 26 ADS flow monitors, each located within a CSO structure.
Significant improvements in collection system management have been experienced by United Water and SWSC.
According to Don Goodroe, program manager for United Water, the innovative technologies in IntelliServe have:
- Improved the accuracy of CSO reporting on dry and wet weather overflows;
- Differentiated between dry and wet weather overflows so the appropriate response can be directed to the cause of the overflow and reports can be filed with an accurate distinction;
- Provided early detection of possible dry weather overflows, which will ultimately lead to a reduction of overflow amounts and elimination of some overflows; and
- Reduced costs through efficiencies in managing, reporting and complying with U.S. EPA regulations on CSOs.
IntelliServe provides an avenue to progress from a reactive collection system management process to a proactive and preventative process for reporting and alleviating overflows in both combined and sanitary sewer systems.