The Infrastructure Services Division of St. Cloud Public Utilities are responsible for inspecting and maintaining the collection system infrastructure and the sanitary sewer lift stations to ensure uninterrupted collection and conveyance of wastewater.
The City has 292 miles of sanitary sewer main lines, and 34 sanitary sewer lift stations. Most of the lines are in the streets or alleys. Some run through utility easements in grassy areas. Each year, the City cleans approximately one-fifth of the City's sanitary sewer lines. Lines requiring a higher level of maintenance are cleaned more frequently. This routine maintenance helps to prevent blockages and backups.
Cleaning the Sanitary Sewer Lines
The sanitary sewer lines are cleaned using high performance sewer cleaning equipment. A cleaning nozzle is propelled from one manhole to the next using water under high pressure. The nozzle is then pulled back to the starting manhole. As the nozzle is pulled back, water scours the inside of the sanitary sewer pipe. Any debris in the pipe is pulled back with the water. The debris is removed from the manhole with a vacuum unit. If roots are found, they are cut with a root cutter. This process is repeated on every sewer line cleaned.
During this process, residents may experience a rumbling sound, in addition to the possibility of water entering your sink, bathtub and/or toilet. Sewer lines can develop air pressure or a partial vacuum from the cleaning process. Usually any excess air pressure or vacuum will dissipate through the plumbing vents, but occasionally there are facilities with inadequate plumbing vents (i.e.: no vents, undersized vents or obstructed vents). In the case of inadequate venting, air pressure could escape through the toilet, floor, sink, tub or shower drains, causing water to splash out or, a vacuum could draw the water out of the fixture traps allowing unpleasant odors.