A municipality has an outdated wastewater lift station. Pumps are about to expire their useful life, while controls need modernization and the access hatch needs to be replaced. The concrete wet well is solid and structurally sound.
Should the station be completely removed? Not necessarily. It is better to ask if the infrastructure that is in place will be able to support a modern system of pumping without compromising capacity in the future and reliability or maintenance access.
Image credit: romtecutilities.com
Retrofitting a pumping station can be a great way to maintain infrastructure and replace parts that are no longer functioning.
Start With the Structure Nobody Would Like to Replace
The wet well can be one of the most costly and disruptive parts to replace as it is located underground, linked to existing piping and is essential to the process of removing wastewater.
If the concrete structure is usable, its retention could minimize excavation and construction work.
However, deterioration around the access hatch could complicate the process. Romtec Utilities has identified wet-well hatch replacement as an important retrofit. Instead of attaching a brand new hatch to a damaged concrete structure and replacing the entire top slab might offer a more long-lasting solution. This can make it easier to access and extend the structure’s usefulness without having to rebuild the entire wet well.
A More Powerful Pump Modifies the Engineering
Imagine that a residential area has increased significantly since the lift station’s initial installation. The pumps that are in place may not be sufficient for the increasing flow of wastewater.
A pumping station upgrade could involve higher-horsepower pumps, but equipment selection cannot happen independently of the surrounding system.
Engineers must also evaluate the system’s hydraulic requirements including the flow and head total dynamic. If you add a larger pump and do not consider these aspects, it can cause problems with operation rather than addressing these. Planning future capacity in the initial design makes future expansion easy.
Make sure that the water for waste is moving throughout the construction process
Retrofitting an existing pump station may present a new challenge. As with other equipment replacement projects, this one will have to remain operational during construction.
Contractors are still working, and wastewater will still arrive. According to the study the project, a temporary bypass pumping system might be necessary to maintain service as the equipment that is in use is removed or new equipment is installed.
Romtec Utilities faced this kind of problem at the Federal Law Enforcement Training Center in Brunswick, Georgia.
The project consisted of replacing two wastewater lift stations that were in poor condition and ensuring the operations of the facility. The project was able accommodate existing station footprints as operating requirements using local-specific engineering and integrated replacement systems. This case illustrates how the order of construction should be considered prior to installation.
When replacement is the better option
Not all stations are suited for rehabilitation. A severely deteriorated wet well, inadequate structural capacity, or significant changes in hydraulic requirements could make sewer lift station replacement more appropriate than changing the existing structure.
The selection should consider the condition of the structure, compatibility with equipment, construction access as well as service continuity as well as long-term requirements for operation. Romtec Utilities begins retrofits and replacements by identifying parts that are to remain and those which need replacement.
From there, the firm develops site-specific engineering solutions as well as preliminary designs and budgetary estimates. Prefabricated components can assist in organize installation, and reduce the amount of construction work that is required on site.
The project won’t be finished until the pumps begin to run.
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, and testing of equipment is required to make sure that all pumps, controls and the related equipment function according to design.
The manuals as well as the training of operators are equally essential. Before they can assume responsibility for an entire station, the personnel in charge of maintenance must know about the latest equipment, procedures and documentation.
Retrofitting infrastructure can preserve its value while eliminating the limitations that prompted modernization.
This means that municipalities and owners of facilities need to think beyond immediate repairs. The most successful project is one that integrates the new equipment with existing structures, provides essential service throughout construction, and prepares the pumping system to last for years to come of operation.
