A deteriorating wastewater liftstation is situated in a municipality. Pumps are nearing the end their service life, and controls require modernization and the access hatch needs to be replaced. Although the concrete wetwell is structurally sound, it’s time to be modernized.
Do you think the station should be completely removed? Not necessarily. It is better to inquire if the system that is in place will be able to support an advanced system of pumping without compromising future capacity as well as reliability or access.
Image credit: romtecutilities.com
A well-engineered retrofit of a pump station can help preserve vital infrastructure while replacing components that no longer meet operating requirements.
Start With the Structure Nobody wants to replace.
Wet wells are typically the most costly and disruptive part to replace, since they are constructed underground and attached to existing pipes and are vital to wastewater collection.
Retaining a concrete structure that is still serviceable can reduce the excavation and construction.
However, deterioration around the access hatch may complicate the choice. Romtec Utilities says that wet well hatches are often replaced in retrofits. It might be more reliable to remove the top slab instead of attaching a new hatch to a deteriorated concrete. This option can be utilized to increase accessibility and the usability of the structure without having to rebuild the whole wet well.
The technology behind an even more powerful pump is different
Suppose a residential neighborhood has seen an increase in population since its original lift station was installed. The current pumps might not be sufficient for increased wastewater flows.
Pumps with higher horsepower could be used to upgrade the pumping station, however the equipment must also fit into the system. To make the pumps more powerful there is a possibility that you will need make adjustments to the discharge elbows, or pipes. You may also need to alter electrical controls and valves.
Engineers must also consider the hydraulic requirements of the system, such as the flow rate as well as the dynamic head total. In the event of installing a larger pump, not studying these factors can lead to problems with operation rather than addressing the issues. Planning for future capacity during the initial design stage can allow for later expansion much more easily.
Keep Wastewater Moving during Construction
Retrofitting an existing pump station could be an entirely new challenge. In contrast to other replacement projects, this one will need to continue operating during construction.
When contractors aren’t busy the wastewater still flows in. Depending on the scope of the project the temporary bypass pumps could be required in order to maintain services during removal and the installation of the existing equipment.
Romtec Utilities was able to take on this task in the Federal Law Enforcement Training Center, Brunswick, Georgia.
The project required the replacement of two older wastewater lift stations in the process of maintaining operation at the facility. Site-specific engineering and packaged replacement systems and bypass pumping strategies helped make room for the station’s footprints and operational needs. This is a good example of why the construction sequence should be considered prior to installation.
When replacing becomes the best option
There are many stations that can be renovated. A severely deteriorated wet well, inadequate structural capacity, or major changes in hydraulic requirements may make sewer lift station replacement more appropriate than modifying the existing installation.
In making a decision, it is crucial to take into consideration the structural integrity of the structure, its compatibility with equipment, its accessibility to construction sites, service continuity and the long-term requirements. Romtec Utilities begins retrofit and replacement projects by determining what elements will remain and which require replacement.
The firm will then develop specific engineering plans for the site along with budget estimates and preliminary designs. Prefabricated parts are also helpful for organizing installation and reducing certain requirements on site.
The Project Isn’t Finished When the Pumps Begin to Run
The modernized lift station should work as a whole. Before returning it to regular service, startup testing and commissioning will help ensure that the controls, pumps and other equipment are operating according to the specifications of the design.
Training for operators and operation and maintenance manuals are equally important. Maintenance personnel should be knowledgeable with the latest equipment and operating procedures as well as the documents before taking responsibility for the station.
Retrofitting infrastructure effectively preserves its value, while also eliminating the limitations that prompted modernization.
For municipalities and facility owners This means looking beyond immediate repairs. The most successful projects integrate new equipment with existing structures. They will maintain the essential services during construction and then prepare the pumping systems to last for a long time.