The sewer lift station of an urban municipality is old. The pumps have reached the maximum lifespan, the controls are outdated as well as the access hatch is damaged. The concrete wet well is solid and structurally sound.
Do you think the station should be completely demolished and rebuilt? Not necessarily. It is essential to consider whether the infrastructure that is in place will be able to support an advanced system of pumping without compromising future capacity and reliability or maintenance access.
Image credit: romtecutilities.com
A carefully engineered pump station retrofit can preserve valuable infrastructure while replacing components that no longer meet operational requirements.
Begin with the Structure that nobody Would Like to Replace
Wet wells can be the most costly and disruptive element to replace because they are constructed underground and attached to existing pipes and are essential to the collection of wastewater.
If the concrete structure remains functional, it is possible to minimize excavation and construction work.
But, any deterioration in the vicinity of the access hatch may complicate the decision. Romtec Utilities says that wet well hatches are typically replaced in retrofits. Instead of gluing a hatch to cement that is degrading replacing the entire top layer might be a more reliable option. This could improve access to the structure and extend its usefulness, without having to replace the entire structure as well.
A More Powerful Pump Modifies the Engineering
If a neighborhood in the area has seen a significant increase in population since the initial lift station was constructed. The current pumps might not be sufficient for increased flows of wastewater.
Pumps that have higher horsepower can be used to improve the pumping station, however the equipment should also be incorporated within the system. Pumps with greater horsepower could require adjustments to discharge elbows, piping and pipework as well as electric controls, valves and other parts.
Engineers should also evaluate the requirements for hydraulics of the system, which includes flow rate and dynamic head total. In the event of installing a larger pump, not taking a look at these requirements could cause problems with operation rather than addressing the issues. The ability to plan future capacity prior to initial design can make future expansion much easier.
Keep waste water moving during construction
A retrofit to a wastewater pump station creates a challenge that regular construction projects for new equipment do not be able to overcome: the station might require to be operational during construction.
Contractors continue to work and wastewater continues to come in. Depending on the project it is possible that temporary bypass pumps will be required to keep services while existing equipment is taken away and new components are put in place.
Romtec Utilities took on this kind of challenge at the Federal Law Enforcement Training Center located in Brunswick, Georgia.
The project consisted of replacing two of the old wastewater lift stations as well as maintaining the operation of the facility. Specialized engineering on site packaging systems, packaged systems and bypass pumping techniques allowed for the existing station footprints and operational needs. This example shows how important it is to think about the sequence of construction prior to installing.
When Replacement Becomes the Better Choice
Not every station is suited to be renovated. If the sewer lift station requires replacement because of a damaged well, structural constraints or significant changes in the hydraulic requirements, it could be more beneficial to replace rather than modify.
The decision should account for structural condition, equipment compatibility construction access as well as service continuity as well as long-term requirements for operation. Romtec Utilities begins retrofit and replacement projects by determining what components will be retained and which need to be replaced.
From there, the business develops site-specific engineering solutions including preliminary designs, as well as budgetary estimates. Prefabricated parts are also helpful for organizing installation and reducing the number of on-site requirements.
The work isn’t over when the pumps kick in
A modern lift station should function as a system in one. Prior to returning it back for regular maintenance, start-up testing and commissioning ensures that the pumps, controls as well as the equipment that is associated with them, are in accordance to the established design.
Both manuals and training for operators are equally important. Maintenance staff should be acquainted with the new equipment and operating procedures as well as the documents before taking charge of the station.
Retrofitting infrastructure successfully preserves its value, while eliminating the limitations that prompted modernization.
This means that municipalities and owners of facilities need to look beyond the immediate repairs. The most successful projects incorporate the latest equipment with the existing structures. They provide essential services while construction is underway and prepare the pumping systems for years of continuous operation.