A decrepit wastewater liftstation is located in a municipal. The pumps are coming to the end of their service life, and the controls require modernization and the access hatch has deteriorated. The concrete wet well is robust and sturdy.
Image credit: romtecutilities.com
Should the entire station demolished and rebuilt? Not necessarily. The more useful question is whether the infrastructure in place will be able to accommodate a modern pumping system with no compromise in security, maintenance access or future capacity.
A carefully engineered retrofit of the pump station could preserve valuable infrastructure while replacing components that do not meet current operating requirements.
Start With the Structure Nobody Wants to Replace
It’s costly and inconvenient to replace the wet-well because it is buried in the ground, linked to piping and is essential to collect wastewater.
The concrete structure can be retained to reduce excavation work and construction.
But, any deterioration in the vicinity of the access hatch can complicate your choice. Romtec Utilities says that wet well hatches can be replaced as part of retrofits. Instead of affixing a fresh hatch to deteriorated concrete or replacing the entire top slab might offer a more long-lasting solution. This will allow for greater access to the structure, and extend its usefulness, without having to rebuild the entire wet well.
A More Powerful Pump Changes the Engineering
Imagine a neighborhood that has exploded in size since the original lift station was installed. The existing pumps might not be able to cope with increased wastewater flows.
A pumping station upgrade could be accompanied by higher horsepower pumps. However, equipment selection isn’t a part of the surrounding system. Pumps with greater horsepower may require modifications to discharge elbows and piping and electrical controls, valves, and other parts.
Engineers should also look at the hydraulic needs of the system. This is a consideration for flow as well as the total dynamic pressure. If you choose to upgrade a pump without taking into account these requirements, it can cause operational problems rather than resolve these. The ability to plan future capacity prior to initial design can make future expansion considerably easier.
Keep waste water moving during construction
A wastewater pump station retrofit introduces a challenge that ordinary equipment replacement projects may not face: the station may need to remain operational throughout construction.
Wastewater continues arriving even when contractors are working. In the case of a project it is possible that temporary bypass pumps will be necessary to ensure operation while the existing equipment is removed, and new components are installed.
Romtec Utilities accepted this challenge in the Federal Law Enforcement Training Center, Brunswick, Georgia.
The project required replacing two old wastewater lifting stations while maintaining operation at this facility. Specific engineering for the site, packaged replacement systems, and bypass pumping techniques helped accommodate the existing station footprints as well as operational requirements. This is a good example of why the sequence of construction is important to consider prior to installation.
In the event that replacing becomes the best option
Some stations may not be suitable for rehabilitation. Sewer lift stations could need to be rebuilt in the event of a badly damaged wet well or a lack of capacity for structural strength.
The decision should account for the condition of the structure, compatibility with equipment construction access to the site, service continuity, and long-term operating needs. Romtec Utilities begins retrofits and replacements by identifying parts that are to remain and those that need to be replaced.
The company will create specific engineering plans for the site, budget estimates, and preliminaries of designs. Prefabricated components are also beneficial in arranging installation and decreasing the number of on-site requirements.
The Project Doesn’t End When the Pumps Are Running
The modern lift station needs to be able to function as a system. Prior to returning a lift station to normal service, startup testing, commissioning, as well as verification of the equipment are essential to make sure that all pumps, controls, and related equipment operate in accordance with their design.
Maintenance and operation manuals, as well as instruction for operators are essential. Maintenance personnel must know the latest equipment, operating procedures, and other documentation before they take over responsibility for the station.
Retrofitting infrastructure can preserve its value while addressing limitations that led to modernization.
Municipalities and property owners have to look beyond immediate repair. The most successful projects incorporate new equipment into existing structures. They provide vital services throughout construction and also prepare the pumping systems for a lifetime of operation.