For several decades, lobe and multistage blowers were the tried-and-true blower technologies for wastewater treatment plants. Over the past 15...
FRU-CON, a construction, engineering and design-build firm based in Ballwin, Mo., hired Thompson Pump to partner with its Woodbridge, Va., office on a two-month bypass project for the Arlington County Water Pollution Control Plant in Virginia. As part of a $200 million refurbishment of Arlington County facilities, a bypass piping system was installed for the line reaction tanks that were being demolished. Thompson Pump and its local distributor, Pump and Power Equipment Corp. in Jessup, Md., collaborated on the bypass by reviewing the project and designing a plan. Consulting firm Malcolm Pirnie and the Arlington County plant approved the drawings, and the 70-million gal per day bypass was set to begin.
The wastewater treatment plant provides water to all of Arlington County, including the Pentagon, so it needed to be operational during the entire project. Because the original plan did not account for this, Thompson Pump and FRU-CON redesigned the job to move the piping system and allow for cranes to access the butterfly valves inside the treatment plant if a change was needed.
Six Thompson 12-inch compressor-assisted dry
prime pumps provided 9,000-11,000 gpm.
A two-day test was conducted before job startup. During the test, the valves on the 60-in. line opened but would not close, causing a slight dilemma. To solve it, the test pumping system was placed online permanently, stopping sewage from leaking onto the ground.
In the project’s first stage, Thompson Pump fused 9,000 ft of 18-in. HDPE pipe and provided two 18-in. pumps with a capacity of 11,000 gal per minute (gpm) and six 12-in. pumps with a maximum capacity of 9,000 gpm. These eight pumps were solids-handling Enviroprime sewage pumps with auto-start/stop capabilities that prevented any spillage, or blow-by, from discharging onto the ground. Each 18-in. line was routed to a single manifold that led into six 18-in. lines.
The project’s residential location presented two obstacles. First, to meet noise limits, the company surrounded the pumps and piping with sound curtains. Despite background noise, including street traffic and a nearby substation, the company stayed below the limit. Second, the equipment needed constant monitoring for the duration of the bypass. To overcome that obstacle, the company staff provided 24-hours-a-day, seven-days-a-week pump watch for three weeks until that portion of the job was complete. An onsite mechanic handled technical support and emergency repairs. In addition to monitoring the wet well, the mechanic ran a test every hour to keep all pumps primed; therefore, if water began to rise, the mechanic could turn the pumps on before the auto start option kicked in.
In phase two, Thompson Pump provided two fusing machines for 30-in. HDPE pipe and installed 900 ft of pipe underground, allowing the pipe to be isolated, drained and inspected. Also, the company replaced 12 large 60-in. butterfly valves.
“Thompson Pump came into this job knowing what needed to be done, and they completed it successfully in a timely and professional manner,” said Jeffery Wade, FRU-CON senior project manager. “With Thompson Pump’s expertise, FRU-CON did not have to expend personnel on the bypass and was able to focus on other aspects of the project.”