The wastewater lift station in a municipality is old. Pumps are nearing the end their useful lives, controls need modernization and the access hatch must be replaced. Even though the concrete wetwell is structurally sound, it’s time to be updated.
Image credit: romtecutilities.com
Should the entire station be destroyed and rebuilt? Not necessarily. The better question is whether the current infrastructure is able to support a modern pumping system with no compromise in the reliability, accessibility to maintenance or capacity in the future.
A well-engineered retrofit of a pump station can help preserve important infrastructure and replace components which no longer meet the operating requirements.
Begin with the Structures No One Will Want to Replace
Wet wells are typically the most expensive and difficult component to replace as they are submerged and linked to existing pipes, and vital to wastewater collection.
If the concrete structure is usable, its retention could decrease excavation and construction work.
But, any deterioration that occurs around the access hatch can complicate the decision. Romtec Utilities identifies wet well hatch replacement as a standard retrofit requirement. It is possible to be more durable to remove the top slab instead of installing a brand new hatch onto deteriorated concrete. This method can be used to increase accessibility and the structural’s functionality without having to rebuild the entire wet well.
A new pump improves the engineering
Consider a neighborhood that has seen a substantial expansion since the establishment of the lift station. It could be that the existing pumps are no longer capable of handling the increased the flow of wastewater.
Pumps with greater horsepower can be used to upgrade the pumping station, however the equipment needs to fit into the system. Pumps with greater power may need adjustments to elbows for discharge, pipes valves, electrical controls and other elements.
The engineers should also take into consideration the requirements for hydraulics of the system, such as the rate of flow as well as dynamic head total. If you choose to upgrade a pump and do not consider these aspects it could create problems with operation rather than addressing these. The planning for future expansions at the time of initial design will enable you to add more capacity later on.
Ensure that the waste water is 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.
Contractors continue working and the wastewater will continue to flow. According to the plan the project, a temporary bypass pumping system may be needed to keep service running while the old equipment is removed, or new parts are installed.
Romtec Utilities fought this kind of problem in the Federal Law Enforcement Training Center at Brunswick, Georgia.
The project consisted of replacing two of the old wastewater lift stations and ensuring the operation at the facility. The project was able accommodate existing station footprints as well operating requirements using local-specific engineering and integrated replacement systems. This example shows the importance of taking time to look at the construction process prior to constructing.
When the Alternative is the Best Choice
Not every station is suited to be renovated. Sewer lift stations could need to be rebuilt if they have a severely damaged wet well, or have a low capacity for structural strength.
The choice should take into account structural integrity, equipment compatibility construction access along with service continuity and long-term operating requirements. Romtec Utilities begins retrofit and replacement projects by determining what components will be retained and which need to be replaced.
The company will then create sites-specific engineering designs along with budget estimates and initial designs. Prefabricated parts can help to simplify installation and decrease construction on site.
The work isn’t done until the pumps begin to run.
A modernized lift station must work as a complete system. Prior to returning it back for regular maintenance, start-up testing and commissioning will help ensure that the pumps, controls and associated equipment perform according to the established design.
Operator training and operation and maintenance manuals are equally important. Maintenance personnel must be familiar with new equipment and operating procedures, and the necessary documentation prior to taking charge of the station.
A successful retrofit preserves the infrastructure and addresses the shortcomings that forced modernization.
This means that municipalities and facility owners need to take a look beyond the immediate fixes. The best projects integrate new equipment into existing structures, and maintain essential service even while construction is in progress. They also prepare the pumping system for continued operation for many years.