A municipality has an outdated wastewater lift station. The pumps have reached the final stage of their life and the controls are inefficient as well as the access hatch is damaged. Although the concrete wetwell appears solid structurally, it requires to be upgraded.
Should the entire station be destroyed and rebuilt? Not necessarily. The most important question is whether the current infrastructure is able to support a modern pumping system without compromising reliability, maintenance access and capacity.
Image credit: romtecutilities.com
The retrofitting of a pumping station that is meticulously designed could save valuable infrastructure and also replace components no longer meeting functional requirements.
Start with the structure that nobody wants to replace.
It’s expensive and time-consuming to replace the wet well since it is submerged in the ground, connected to pipes and is vital to collect wastewater.
If the concrete structure remains functional, it is possible to decrease excavation and construction work.
But, any deterioration that occurs around the access hatch can complicate the choice. Romtec Utilities says that wet well hatches are typically replaced as part of retrofits. Rather than attaching a new hatch to a damaged concrete structure or replacing the entire top slab could make a more robust solution. This approach can improve access and improve the functionality of the structure without re-building the entire wet well.
A More Powerful Pump Modifies the Engineering
Consider a neighborhood that has seen significant increase since the opening of a lift station. It is possible that the existing pumps are no longer sufficient to handle the increasing water flow.
A pumping station upgrade could involve higher-horsepower pumps, but equipment selection cannot happen independently of the surrounding system.
Engineers must also take into consideration the hydraulic needs of the system. This is a consideration for flow as well as the total dynamic pressure. Installing a larger pump without taking a look at these requirements could cause operational problems rather than solving them. Planning for future capacity during the initial design stage can make later expansion considerably easier.
Keep the Wastewater Moving During Construction
Retrofitting an existing pump station can be an entirely new challenge. As with other equipment replacement projects, the station will require continued operation for the duration of construction.
Even if contractors are busy and preparing for the next project, wastewater is still arriving. Depending on the project, temporary bypass pumping may be necessary to ensure operation while the existing equipment is removed and new components are erected.
Romtec Utilities took on this kind of challenge at the Federal Law Enforcement Training Center located in Brunswick, Georgia.
The project involved the replacement of two old wastewater lifting stations, whilst maintaining operation at this facility. Site-specific engineering, packaged systems and bypass pumping techniques made it possible to meet existing station footprints and operational needs. The case study illustrates why the sequence of construction should be considered before the construction process starts.
When replacement becomes the better Option
Not every station can be rehabilitated. Sewer lift stations might need to be rebuilt when they have a seriously damaged wet well or a lack of structural capacity.
The selection should consider the condition of the structure, compatibility with equipment, construction access as well as service continuity and long-term operational requirements. Romtec Utilities begins retrofits and replacements by identifying elements which are expected to stay and the ones that require replacement.
The company then develops engineering solutions specific to the location, initial designs as well as budget estimations. Prefabricated components can assist in make installation easier and less time-consuming, as well as reduce on-site construction.
The Project is not Complete When the Pumps Are In Place
The modernized lift station should work as a whole. Before returning it for regular maintenance, start-up testing and commissioning will help ensure that the pumps, controls, and the associated equipment work according to the specifications of the design.
Manuals for operation and maintenance and also instruction for operators are crucial. Maintenance staff should be acquainted with the latest equipment and operating procedures, and the documentation before they take charge of the station.
A successful retrofit will preserve the infrastructure, while addressing the issues that required modernization.
Municipalities and owners of facilities must look beyond immediate repair. The most successful project is one that integrates the new equipment with existing structures, keeps up with essential services throughout construction and also prepares the pumping system to last for years of continued operation.