Reasons for clogs
Clogs in residential service lines:
- Material other than the 3Ps is flushed down the toilet.
- In older areas, the clay tile pipes that form the line are generally connected by tar. Tar breaks down over time and releases moisture, which attracts tree roots. This problem is compounded when the residents flush wipes, diapers and other non-flushable material that gets caught on the tree roots.
- An aging pipe can form a ripple or bump, slowing the speed of the effluent so the matter can’t exit the pipe as quickly as it is designed to do. When this occurs, the material in the pipe can more easily form a mass and eventually clog the pipe.
- Sometimes the service lines can settle slightly, creating a sag. Pipes can usually accommodate the 3Ps even when they sag, but “non flushables” can collect in the lower portion of the sagging pipe.
Clogs that occur in residential service lines generally affect only that property. It is the responsibility of the resident to pay for having the clog cleared.
Clogs in the city's sewer mains:
- Material (such as diapers and wipes) other than the 3Ps is flushed down the toilet. Wipes and diapers are fibrous, and fibrous material encourages other foreign materials to stick to it. If the mass becomes large enough, it clogs the main.
- An aging pipe can form cracks, ripples, bumps or sags, slowing the speed of the water and 3Ps so the matter can’t exit the pipe as quickly as it is designed to do. When this occurs, the material in the pipe can more easily form a mass and eventually clog the pipe.
- As with residential service lines, sections of pipe that form the line in older areas are connected by compounds that break down over time. When that happens, the compounds release moisture, which attracts tree roots. This problem is compounded when residents flush wipes, diapers and other non-flushable material that gets caught on the tree roots.
- All sewer pipes have an expected life. As they near the end of their useful life they can form structural defects such as cracks, fractures and holes.
Clogs in the regional lines or at the headworks:
- Repairs are difficult because of the large diameters of the pipes and the amount of water needed to flush them when required. New technology will allow flusher/vacuum (hydrovac) trucks to recycle the water used to flush the lines but that water must also be clear of unflushables.
- Most clogs in the regional system occur at the headworks where the screens need significant clearing of foreign matter.
- Diapers and wipes, among many other nonflushables, also get into the pumps.
- Crews then have to disassemble the pump to clean it. If that is unsuccessful, the pump must be sent away for repair or replacement. This is costly and puts additional pressure on the remaining pumps to keep our wastewater system efficiently processing the region’s huge volumes of wastewater.