Upgrading Sun City Center's sewage infrastructure.
The question has been raised as to what all those trucks are doing that are parked in the middle of our streets near manholes. The answer is that they are involved in a massive relining project of 16.78 miles of the 50+ year old gravity sewer lines in the Sun City Center area. Originally the sewer pipes were terra cotta which was state of the art back then. PVC is the current state of the art. So, an inner lining of PVC is now being applied to the old pipes.
Here are photographs that I've taken over the past couple of years, starting with the initial camera survey of the old terra cotta pipes to check for cracks and leaks, through to the current relining process.
A bladder in placed in the sewer line and inflated to keep the upstream waste out of the work area.
A remote controlled camera equipped with lights is run through the pipe.
The camera looks for problems and also exactly locates the 4" laterals that come from each home into the main sewer pipe. A truck with a "viewing room" controls the camera. The precise distance that the camera has traveled is displayed on the screen. Written notes and a video tape are made of the survey for later review.
Because I showed an interest, one of the workman ran the camera down the street so that I could see it move.
The liner is made of a specially formulated PVC which is normally rigid but becomes very pliable when heated with steam. The liner is flat on rolls at the start of the process. It is in an enclosed steam cabinet. You can see the big roll of flat PVC liner in this photograph.
Then steam is applied to make the liner really pliable.
The end of the liner is pulled out of the steam cabinet...
And pulled down through the manhole to the next manhole - typically 400' to 600'
Here's the liner coming out of the next manhole.
The end of the pipe is neatly cut off.
A specially contoured plug is installed in the cutoff end.
Steam is run through the pipe to make it very pliable.
After a half-hour or so, the valves are closed and 105 psi steam pressure is applied which inflates the liner against the old terra cotta.
After the lining cools, it is trimmed down in the manhole.
When the liner inflates against the old pipe, it closes off the 4" laterals coming from each home. A camera and rasp cutter is sent through the newly relined pipe and cuts a hole at each lateral, based on the precise measurements that were made at the time of the survey.
Close-up of the rasp cutter tool. A second pass is made with a deburring tool to smooth the edges of the hole.
The final step is to grout between the main pipe and hole that was cut for the lateral. A grouter unit and camera are pulled through the pipe.
First a sealing bladder (yellow) is expanded up the lateral of each home. Then the two bladders (black) on either side are expanded to seal the pipe. Finally, a quick-set resin grout is pumped in to complete the grouting process.
This is how the grout bladder looks when it is inflated. It is referred to as a "donkey dick".
This is the view in the main pipe after the grout bladder (yellow) has been inflated up into the lateral, but before the pipe sealing bladders have been expanded and the grout injected.
And this is the finished product of a lateral grouted to the new PVC liner.
The relining cost is about $22 per foot. The sewer line in the middle of my street is a little over 400' long. So the cost to reline Burlington Circle's sewer pipe was around $8000-$9000.
The PVC liner process is used for pipes up to 12 inches in diameter. For larger pipes, such as the 24" sewer line that runs under the center of West Del Webb, a process called "Cured In Place" is used.
A fiberglass liner that is impregnated with a heat set resin is pulled through the pipe. Cold water is run into the liner to inflate it against the walls of the old pipe. See the bulge under the holding frame.
Over a period of about two hours, the water is circulated and heated to 180 degrees, held at that temperature for about two hours, and then allowed to cool down for about two hours. After that, the holes to the individual homes' laterals are cut and grouted, just like in the PVC liner process.
Lift station rehab:
In addition to relining the sewer pipes, Hillsborough County is also upgrading a number of lift stations in our area. Overall, there are about 700 lift stations in the County.
Lift stations collect the sewage in large concrete "wells". For the lift station on West Del Webb, there is one concrete well which is 12' in diameter and 35' deep. Within the well are three pumps that take turns pumping the sewage on down to the sewage treatment plant on the west side of Interstate 75. The current repairs are deemed "urgent" because the gases, probably from burritos, have eaten away the concrete and pipes. The new stainless steel pipes and pumps have already been installed. The well is being relined by pressure washing the well walls, applying a sealant, applying 6" of foam and then another layer of sealant. These current repairs to the West Del Webb lift station are costing about $130,000.
This is one of the pumps lifted out for the cleaning.
This is a view down into the well after it has been thoroughly pressure washed in preparation for sealing. The workmen stand on the scaffolding in the foreground to do their work.
And this is a view down into the well after it was relined. Note the new foam and pink sealer on the walls of the well to protect the concrete until more extensive repairs can be made in 3 or 4 years. You can see the three pipes that go to the three pumps that take turns pumping the sewage on down to the sewage treatment plant on the west side of Interstate 75. The ring at the bottom left is a diffuser for the entering sewage. The greyish liquid at the bottom of the well is the essence of the Obama administration.
And when all of the temporary repair work was completed, the original chain-link fence was replaced with a nice wood slat fence that greatly enhanced the lift station's general appearence.