The sewer lift station in an urban municipality is old. The pumps are approaching the expiration date of their service life span, the controls require modernization and the access hatch has become damaged. The concrete wet well is robust and sturdy.
Should the entire station be demolished and rebuilt? Not necessarily. The more important issue is whether the current infrastructure will be able to accommodate a modern pumping system with no compromise in reliability, maintenance access, or future capacity.
Image credit: romtecutilities.com
A carefully engineered pump station retrofit can preserve valuable infrastructure while replacing components that no longer meet operational requirements.
Start with the Structure That No One Would Like to Replace
It’s expensive and time-consuming to replace the wet well because it is in the ground, linked to pipes and essential for the collection of wastewater.
A concrete structure that is functional can reduce the excavation and construction.
However, the deterioration around the access hatch may complicate your choice. Romtec Utilities identifies wet well hatch replacement as a typical retrofit requirement. It could be more durable to repair the top slab instead of installing a brand new hatch on concrete that has deteriorated. This can increase access to the structure, and extend its utility, without having to completely rebuild the wet well.
A More Powerful Pump Modifies the Engineering
Take a look at a neighborhood that has seen a substantial expansion since the establishment of its lift station. The pumps that are in place may not be able to handle the demand for increased wastewater flows.
A pumping station upgrade could involve higher-horsepower pumps, but the choice of equipment cannot be made independently of the rest of the system. For more powerful pumps there is a possibility that you will need change the discharge elbows or the piping. You might also have to alter electrical controls and valves.
The engineers must also assess the requirements for hydraulics of the system, such as flow rate and dynamic head total. If you add a larger pump without taking into account these requirements it could create operational issues rather than solve the problem. Making plans for future expansions during initial design will help you to expand later on.
Make sure that the water for waste is moving during construction
Retrofitting a wastewater pump station may present an entirely new challenge. Contrary to other equipment replacement projects, the station will have to remain operational throughout construction.
Contractors continue to work and wastewater will still arrive. Based on the nature of the project an interim bypass pumping system may be necessary to ensure service while existing equipment is taken away and new components are installed.
Romtec Utilities took on this kind of challenge in the Federal Law Enforcement Training Center located in Brunswick, Georgia.
The project involved the replacement of two old wastewater lift stations and ensuring the operation of the facility. The project was able to accommodate the footprints of existing stations as well as operational requirements by using local-specific engineering and integrated replacement systems. This illustrates the reasons why the sequence of construction is important to consider prior to installation.
If replacement is the best alternative, then replacement is the best
Some stations may not be suited for rehabilitation. If the sewer lift station is in need of a replacement because of a damaged well, structural problems, or significant changes in hydraulic requirements, it might be better to replace than alter.
It is vital that the choice taken into consideration structural conditions, equipment compatibility and accessibility to construction, as well longer-term operational requirements. Romtec Utilities begins retrofits and replacements by identifying elements to be left in place and those that need to be replaced.
The business will then design specific engineering plans for the site along with budget estimates and preliminaries of designs. Prefabricated components also aid in to organize installation and decrease some building requirements that are required on-site.
The Project Doesn’t End When the Pumps Are Running
The modernized lift station should work as a whole. Before returning a lift-station to normal service, startup tests, commissioning as well as verification of equipment are required to verify that all pumps, controls and the related equipment function as designed.
Both manuals and training for operators are equally vital. Maintenance staff must understand the latest equipment, operating procedures, and documents before they can assume responsibility for the station.
Retrofitting successfully preserves infrastructure that still has value as well as addressing the weaknesses which led to the need for modernization.
This means that municipalities and owners of facilities must look beyond the immediate repairs. The most successful project is one that integrates the new equipment with existing structures, keeps up with essential service during construction and also prepares the pumping system to last for years of continual operation.