Credit: Thompson Pump

Two 16-inch and four 12-inch solids-handling ENVIRO-PRIME sewage pumps bypassed 71 mgd for two weeks at the Arlington County, Va., Water Pollution Control Plant; the setup provided accessibility for crews to inspect 900 feet of pipe and replace 12 60-inch butterfly valves.

In 2001, America's infrastructure received a D+ grade from the American Society of Civil Engineers. Four years later, the overall grade declined to a D, with wastewater treatment receiving a D-. The longer it takes for our wastewater infrastructure to be improved, the more it will cost to solve the crisis and create a safer environment.

For municipalities facing that difficult task, pumping systems are critical. Bypass systems can be used at treatment facilities and on sewer lines to reroute flows temporarily so public utility engineers can inspect, service, or repair an existing structure. Atrained bypass specialist can provide relevant engineering expertise on any project, saving time and money. A bypass specialist can provide all pumps, equipment, and labor to design, set up, install, monitor, and remove a bypass system.

Temporary bypass systems come in three forms. Open systems involve suction from sources open to the atmosphere and pumping to other open sources. Closed systems take suction from a closed source with pressure to another closed source. Combination systems take suction from an open system, such as a manhole, and pump into a closed system like a force main.

Several steps must occur to ensure that a project is completed under budget and on time. The most critical aspects of any bypass project involve estimating anticipated flows and calculating proper discharge size. Other factors include pumping properties, location of suction and discharge piping, and system head requirements. A bypass specialist also establishes equipment requirements, including pumps, priming systems, valves, monitoring equipment, and pipe plugs. Then, the specialist must create project specifications and pumping requirements to determine a project's scope.

Allowing a bypass specialist to examine a jobsite may alter a project, but it allows measurement of various elevations and depressions, and accurate draft sketch drawings. Asite visit may reveal other useful information on special environmental and safety regulations, convenient power sources, permit requirements, and liability concerns. A visit also lets a specialist note factors that demand special consideration, including major highways, traffic control, and businesses and residential areas that require specialized equipment.

For example, projects near residential areas or hospitals may require sound-attenuated pumping units. Residential areas also entail security concerns that may warrant phone dialers or auto start/stop devices. Inclement temperatures could justify packages designed for cold weather or heaters. Although these items may increase costs, they can help prevent problems.

Once logistics and regulations are determined, bypass setup begins. A bypass specialist is responsible for coordinating deliveries of all pumps, fusing high-density polyethylene pipe, providing safety and testing equipment, and setting up suction and discharge hose and piping. Creating a bypass system may take days to complete and properly test. Once a system is in operation, a specialist also can oversee it continuously if necessary, or a municipality may consider a system for remote monitoring and alarm notification.

Abypass specialist ultimately provides a temporary solution to an immediate need, using the most efficient and innovative equipment available to complete a job properly and on time. Agencies that rely on a bypass specialist will operate more efficiently and complete infrastructure upgrades in a timely fashion.

— Majid Tavakoli is vice president of applied products with Thompson Pump & Manufacturing Co. Inc., Port Orange, Fla.