Monitoring Sensors Prevent Sanitary Sewer Overflows

About the Program

Category: County Resiliency (Best in Category)

Year: 2017

The Miami-Dade Water and Sewer Department (WASD) deploys an extensive network of remote level monitoring sensors. These sensors are used to monitor and respond to rising levels of water in manholes within the wastewater collection system which, if left unattended, would result in sanitary sewer overflows (SSOs). SSOs occur when wastewater seeps through the ring and cover of the manhole on to the surrounding surface area where it can impact the public and/or the environment. When a pipe becomes blocked by illegal discharges, it can lead to a SSO in the form of a manhole overflow. WASD holds monthly meetings to analyze the root cause of SSOs that occurred the previous month. When these SSOs are analyzed and the associated asset has required maintenance within the previous 3 years, the asset is designated as a Hot Spot for remote level monitoring. This enhanced level of service allows the department to monitor and react to rising levels in the manhole before a SSO occurs. WASD employs 59 remote monitoring sensors that provide alarms to staff when levels reach a pre-determined threshold. A response crew is dispatched to resolve the level rise and prevent a potential overflow. SSO prevention and remote monitoring has multi-faceted benefit, which includes positive social, environmental, and fiscal impacts. The potential contact of the public being exposed to raw sewage is prevented, as well as to open bodies of water, storm drains and sensitive wildlife. The fiscal benefit includes the decreased chances of regulatory penalties resulting from SSOs, as well as the costs associated with spill clean-ups. The number of High Frequency Cleanings (HFC) in areas having a history of spills have decreased by 80 percent due to remote level monitoring. This allows the utility the ability to deploy cleaning resources on time, but no more frequently than needed, resulting in a drastic amount of operating costs. This also leads to an increase in life expectancy of the pipes that no longer have as frequent the number of HFCs.