The City of La Mesa, California, has a rigorous cleaning maintenance program to cover its 155 miles of gravity sanitary sewers. All pipes are cleaned annually and the city also has 100 sites that — due to issues such as root intrusion — are cleaned monthly. The work is performed in house by an efficient eight-person staff split equally between scheduled annual cleaning and monthly hot spots.

The city has an excellent track record of preventing sanitary sewer overflows (SSOs). However, it recognized that regular, high-frequency pipe cleaning is damaging the system, particularly in parts of the city with older, high-risk segments. As a result, La Mesa looked for a new approach to reduce operational demands, alleviate premature pipe wear and continue to prevent overflows.

Remote site monitoring

Using continuous remote site monitoring, ADS Environmental Services worked with the La Mesa to determine when and where to clean. The city selected 10 monthly sites and deployed advanced level monitors at each site. Water levels were monitored for changes, and low-flow and high-flow alarms were configured for each site to ensure SSOs were prevented. 

In the first three months, only one of the 10 sites was impacted. That location had a water level increase greater than 10 percent when compared to the starting baseline and that site’s depth-over-diameter ratio was only 0.24. As a result, no cleaning was required at that site, resulting in a 100 percent reduction for the three-month period. 

The city and ADS Environmental Services continue to work together to generate additional data for each of the 10 sites to determine the best cleaning frequency. 

ADS Environmental Services offers flow information from real-time flow data to temporary flow monitoring reports. ADS also offers level monitoring to provide early warning of preventable blockages.

256-430-3366 | www.adsenv.com