The sewer lift station of an urban municipality is old. The pumps are at the expiration date of their useful lifespan, the controls require modernization, and the access hatch has deteriorated. However, the concrete wet well is robust and solid.
Should the entire station be destroyed and rebuilt? Not necessarily. It is important to inquire if the system 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 pump station could be an excellent way to save infrastructure and replace elements that have become obsolete.
Start with the Structure That No One Would Like to Replace
The wet well can be one of the most expensive and disruptive components to replace, as it’s located underground, linked to existing pipes, and crucial to the collection of wastewater.
If the concrete structure is serviceable, retaining it may decrease excavation and construction work.
The deterioration of the area around the access hatch could cause problems with this decision. Romtec Utilities identifies wet well hatch replacement as a typical retrofit requirement. It might be more reliable to replace the top layer instead of attaching a new hatch onto deteriorated concrete. This approach can improve access and enhance the utility of the structure without rebuilding the complete wet well.
The technology behind a more powerful pump is distinct
Imagine a place that has exploded in size since the initial lift station installation. Existing pumps may not be able to deal with the increased flow of wastewater.
The improvement of a pumping unit could include higher-horsepower equipment, but it is not possible to do this without considering the surrounding system. Pumps that have higher horsepower might require modifications to the discharge elbows and pipes and electrical controls, valves and other parts.
Engineers must also consider the hydraulic requirements of the system, including the flow rate and the total dynamic head. Installation of a larger pump without considering the circumstances may cause more issues than it resolves. Making plans for future capacity in the initial design phase can simplify future expansion.
Keep Wastewater Moving during Construction
Retrofitting a wastewater pump station poses a challenge which normal replacement of equipment projects do not encounter: the facility may need to remain operational throughout construction.
Contractors continue to work, and wastewater will still arrive. According to the report it is possible that a temporary bypass pumping system is required to ensure service is maintained as the equipment that is in use is removed or new parts are installed.
Romtec Utilities tackled this type of challenge in the Federal Law Enforcement Training Center in Brunswick, Georgia.
The project involved replacing two aging wastewater lift stations, while operating the facility. Specialized engineering on site packages, bypass pumping techniques allowed for the existing station footprints as well as operational requirements. This example shows the need to be aware of construction sequencing prior to the installation process begins.
When the Alternative is the Best Choice
Not all stations are suitable for rehabilitation. 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.
The decision should account for structural health, equipment compatibility construction access, service continuity, and long-term operational requirements. Romtec Utilities begins retrofits and replacements by identifying elements which are expected to stay and those which need replacement.
The company will then create site-specific engineering designs as well as budget estimates and preliminary designs. Prefabricated components also aid in organize installation and reduce some needs for construction on site.
The Project is not Completion until the Pumps Have Set to Start
A modern lift station should be able to function as an integrated system. Prior to returning the lift station to service, testing its startup and commissioning are a way to make sure that the pumps, controls and other equipment are operating in accordance with the accepted specifications.
Operator training, as well as maintenance and operation manuals are equally important. Maintenance personnel should be familiar with the latest equipment as well as operational procedures, as well as the documentation before they take responsibility for the station.
An effective retrofit will preserve the infrastructure that is still valuable and addresses the shortcomings that led to modernization being necessary.
This means that municipalities as well as facility owners must look beyond the immediate repairs. The most effective project is one that integrates new equipment into existing structures, ensures vital services throughout construction and also prepares the pumping system to last for years of continued operation.