Maintenance of the sewer lines is essential in ensuring that waste water flows freely from our District to the South Valley Water Reclamation Facility for treatment. We use several processes to keep the lines clean and in good repair, to help minimize the damage that can be caused by broken or blocked lines.
Every year, usually beginning in March, we use a high pressure water system to flush the grit and debris out of our lines. We begin at the top of our District and, using a 2,000 p.s.i. water nozzle, we work our way down toward the treatment plant.
Starting at the manhole, we pull the cover and drop the nozzle into the line, feeding the hose down to the next manhole, approximately 350 to 400 feet away. Then we retrieve the nozzle and move to the next manhole and start the process again, cleaning every accessible line in the District. This process takes approximately seven months to complete, usually finished by October.
We have approximately 3,500 manholes throughout our District. Most of these are in the streets, but some are in backyards and fields. They are approximately 350 to 400 feet apart and require maintenance on a regular basis as well. For example, when a road is paved, the manhole cover is now lower than the rest of the road and needs to be raised.
We use a jackhammer to remove the asphalt from around the manhole collar, then we raise the level by adding an additional collar on top of the existing one. There are also times when an existing collar has to be removed and a new, larger collar installed. Once completed, concrete is poured around the collar to finish the process.
These manholes are critical in maintaining the integrity of our lines. Vandalism hinders our ability to keep our sewer system running smoothly and efficiently. At times we find that the covers have been removed and sticks, rocks or other debris are tossed into the manholes.
This can cause damage to the manholes and lines and can quickly cause flow to backup and damage homes. If you ever see anyone other than District personnel opening a manhole cover, please call our District immediately at 801-561-7662. We appreciate your assistance in keeping our sewer system working efficiently at all times.
On the following video, there is a mass of tangled roots on the left side of this 8 inch pipe. This video shows the root cutter coming into the line and breaking up the roots that are blocking the flow from moving down the line. You will see the level of the water in the pipe rise rapidly as the root cutter forces water back against the camera as it comes up the line. To play, right click on the video and select "Play". The video lasts approximately 1 minute and 15 seconds.
We use special line cameras to visually inspect our sewer lines. It is essential to keep our lines in good repair and we accomplish this by searching for potential problems such as cracks or other defects in the pipes, or even roots that have broken into the lines.
We use the camera to videotape the line, which we then use to determine when and where lines need to be repaired or replaced. We also use the camera to visually inspect lateral connections to our main lines, to determine if problems exist at the connections.
We have many manholes in which a smaller line enters and a larger diameter line exits the manhole. After jet cleaning such a line, it is common for grit to settle in the larger diameter line, since it lays slightly deeper than the incoming line.
When this occurs, we remove the manhole cover and use a vacuum truck to remove the excess grit from the line. Approximately 25% of our lines require vacuuming and we remove about five tons of dirt, grit and debris from our system and deliver it to the treatment plant each year.
In many neighborhoods, there are older trees with deep, thick roots that invade our lines. These roots block the flow in our system and can eventually cause problems and damage. We use a root cutter to clear our lines of roots and keep the flow going.
In recurring problem areas, we have also performed root treatment, which involves injecting a foam into the lines that dissolves the roots, which are then flushed through the system. This is done where roots affect large areas of pipes.