Sunbelt Rentals’ South Jersey Pump & Power location recently performed a challenging pump job in historic Wilmington, DE, utilizing four of its new 15-centimeter (6 in.) Quiet Flow diesel-driven trash pumps. This project was a sewer bypass application performed at an upscale condominium complex, during the repair and rehabilitation of a 91-centimeter (36 in.) concrete and terra cotta sanitary sewer line.
Brandywine Park Condominiums are located along the Brandywine River, on the site of an old paper mill dating back to the 1800s. In fact, its main building is a stone structure that was part of the original mill. When the site was developed into a condominium complex during the 1980s, a parking deck and an eight-story tower were added. Unfortunately, these new buildings were constructed right over an existing 91-centimeter (36 in.) sanitary sewer line.
When it was discovered that the sewer line was leaking underneath the buildings, New Castle County retained Tetra Tech, an engineering firm based in Christiana, DE, to design a solution. Realizing that replacing the pipeline was impractical, Tetra Tech developed a plan to repair the existing pipeline. This plan was designed around an innovative restoration technique that is becoming quite popular in the United States: the installation of a cured-in-place (CIPP) liner. This enabled the renovation of a 180-meter (590 ft.) section of the existing sewer line without excavation, commonly referred to as “trenchless technology.” Other repairs included the construction of a header system for connecting several lateral lines running underneath the buildings and a 18-meter (60 ft.) concrete encasement under an unsupported section of the existing sewer line.
Am-Liner East Inc. of Vienna, VA, was contracted by New Castle County to perform the rehabilitation project. To enable access to the existing sewer line during repairs, a temporary bypass pumping system was required to divert the wastewater flow around the project. A major consideration in selecting the pumps for this application was noise — the pumps had to be installed right beside the main building of the condo complex, where residents would be subject to the sound of diesel engines running 24 hours a day. The Brandywine condo association stipulated that only quiet-running pumps could be utilized.
“We looked to Sunbelt Rentals to supply the pumps on this project, since we’ve had good results working with them on several previous jobs,” said David Giuliani, one of four brothers who own Am-Liner. “All the other pump suppliers wanted to just ship us some pumps and pipe and make us do the installation. Kyle [Horgan, manager of South Jersey Pump & Power] designed an entire bypass pumping system and quoted us a turnkey installation. Sunbelt is definitely a full-service company.”
Sunbelt’s new Quiet Flow diesel-driven trash pumps provide ultra-quiet operation (66-dba at full load). Three 15-centimeter (6 in.) Quiet Flow pumps were utilized to perform the primary bypass pumping on the Brandywine project. Two of the pumps ran continuously, with the third pump equipped with a float switch to provide automatic startup/shutdown as backup. Wastewater flow during the project averaged 4.3 million gallons per day.
Another concern on the Brandywine project was protecting the environment from any accidental leakage during the bypass pumping operation. There was no right-of-way along the river beside the condominium tower and parking deck, so the pipeline had to be installed right in the river.
“We utilized 12-inch diameter high-density polyethylene pipe in 40-foot sections with Vitalic couplings,” said South Jersey Pump & Power’s Hogan. “This type of pipeline is very reliable, combining a lightweight design with high flow capabilities. It also provided the flexibility we needed to make gradual bends in the pipeline to follow the shoreline of the river.”
Placement of the three primary pumps was another challenge tackled by Sunbelt Rentals — there was no vehicle access to the small clearing beside the main condo building where the pumps needed to be installed. After being delivered to a nearby service road on Sunbelt’s boom truck, the three pumps had to be lifted and placed into position by crane. A 135-metric-ton (150 ton) hydraulic truck crane was utilized to lift the pumps nearly 30.5 meters (100 ft.) over a grove of trees into the small clearing.
The suction lines from the three pumps were routed to a nearby manhole on the upstream side of the sewer line section being repaired. The discharge lines were connected to a manifold, which combined the flow from the three pumps into a single 30.5-centimeter (12 in.) pipeline. Galvanized steel pipe with Bauer couplings was utilized to carry the discharge flow approximately 23 meters (80 ft.) to the edge of the river, where it was connected to the 30.5 centimeter (12 in.) high-density polyethylene (HDPE) pipeline.
Once past the condo complex, the HDPE pipeline was routed on land, discharging into a manhole located beyond the scope of the project. The pipeline was assembled along (and in) the river by Sunbelt pump specialists wearing “chest waders.” A Sunbelt Rentals boom truck equipped with an articulating crane assisted with the placement of the 12-meter (40 ft.) HDPE pipe sections along the river. As it was assembled, the pipeline was floated upstream toward the primary pump installation, where it was connected to the galvanized steel pipe from the pump manifold. The total length of the HDPE pipeline was 256 meters (840 ft.).
A fourth pump was installed beyond the condominiums to bypass flow from several intersecting lines running underneath the buildings. These lateral lines were connected to a temporary header system installed by the contractor. Discharge from this pump was routed to the same manhole where the HDPE pipeline ran, using 15.24-centimeter (6 in.) lay-flat hose. Sunbelt Rentals also provided a conventional 10.16-centimeter (4 in.) diesel-driven trash pump as an emergency backup unit.
“Sunbelt’s crew did a fine job putting the bypass system together under really tough conditions. They were also very responsive, stoping by almost daily to check on the pumps,” said Phillip Giuliani, project manager on the Brandywine job. “We had excellent fuel economy on the pumps, averaging about 30 gallons per day running continuously. They also ran quiet enough to keep the condo residents happy.”
As soon as the installation was complete and the pumps were up and running, a pipe plug was inserted in the existing sewer line to enable Am-Liner’s crew to begin its repair work. The crew’s first order of business was to inspect the inside of the pipeline for any damages and obstructions. A video inspection unit was utilized to perform this operation, which revealed numerous abnormalities as well as chunks of concrete and other debris inside the sewer line. Over the course of about three weeks, Am-Liner workers performed repairs inside the pipeline using specialized tools and equipment. Once repairs were completed and a final inspection performed, Am-Liner was ready to install the new liner.
The liner itself was custom fabricated for this project by Am-Liner at their factory in Wallace, NC. It is described as a long polyester felt tube with an outer coating of polyurethane. The tube was impregnated thoroughly with a liquid resin chosen to match the requirements of the project. The completed liner was then transported to the Wilmington, DE, site in a refrigerated trailer.
On site, Am-Liner utilized a specialized trailer-mounted rig to install the new liner inside the existing, sewer line. This rig is equipped with a hydraulically raised platform. which was positioned over the manhole where the liner was inserted. The lead end of the liner was turned inside out for a predetermined length and clamped to a collar over the installation manhole. Water was then introduced into the turned back section creating a head, causing the liner to continue turning inside out as it was forced through the old pipeline. The constant addition of water maintained the head, keeping the liner inverting and pressing the resin-impregnated surface firmly against the host pipe.
When the insertion of the liner was complete, the water inside the liner was circulated through a fuel-fired boiler mounted inside the trailer-mounted rig, gradually raising the water temperature to 185-degrees Fahrenheit. This temperature was monitored and maintained for 20 hours to “cure” the liner in-place. The curing time was predetermined, based upon the diameter and length of the pipeline section under renovation. Once the cure was complete, the ends of the new liner were cut and trimmed, enabling Am-Liner’s crew to proceed with performing the remainder of the project.
“We achieved excellent results installing the new liner on this job,” said David Giuliani. “With Sunbelt Rentals taking charge of the bypass pumping, we were able to concentrate fully on what we do best — repairing the pipeline.”
For more information, call Sunbelt Rentals’ South Jersey Pump & Power at 856/779-2772.
(This article appears courtesy of Sunbelt Rentals Marketing Bulletin.)