A municipality is home to an aging wastewater lift station. The pumps are nearing the limit of their lifespan The controls are old as well as the access hatch is damaged. The concrete wet well remains structurally sound.
Should the entire station be demolished and rebuilt? Not necessarily. The better question to ask is whether or not the existing infrastructure will be able to support the pumping system of modern standards without compromising reliability or 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 Nobody Would Like to Replace
Wet wells are typically the most expensive and difficult component to replace, as they are underground and connected to existing pipes, and essential to the collection of wastewater.
Retaining the concrete structure may decrease excavation and construction work.
The deterioration of the area surrounding the access hatch may cause problems with this decision. Romtec Utilities has identified wet-well hatch replacement as an important retrofit. It could be more durable to remove the top slab instead of attaching a new hatch on deteriorated concrete. This could improve access to the structure, and extend its usefulness, without having to completely rebuild the wet well.
The development of pumps that are more powerful is different
Imagine a place that has seen a significant increase in population since the original lift station installation. Existing pumps may not be able to deal with increased wastewater flows.
The upgrading of a pumping system could be accompanied by higher horsepower equipment, however this can’t be accomplished without considering the surrounding system. Pumps that have higher horsepower might require adjustments to the elbows for discharge and piping, as well as electrical controls, valves and other parts.
Engineers must also take into consideration the hydraulic needs of the system. This includes flow and total dynamic pressure. The installation of a bigger pump prior to assessing the requirements could cause more problems than it solves. Making plans for future expansions during the initial design phase will allow for a much simpler process to grow in the future.
Keep waste water moving during construction
A wastewater pump station retrofit presents a problem that normal project for replacement of equipment may not have to face: the pump station may require operation through the entire construction.
Even when contractors are working and preparing for the next project, wastewater is still arriving. According to the scope of the project temporary bypass pumps might be required to ensure the service throughout the removal and installation of the existing equipment.
Romtec Utilities addressed this type of challenge in the Federal Law Enforcement Training Center in Brunswick, Georgia.
The work involved replacing two wastewater lift stations that were in use and ensuring the operation of the facility. The project was able to adapt to the footprints of existing stations as well the operational needs by utilizing local-specific engineering and packaged replacement systems. This case illustrates why the construction sequence is important to consider prior to installation.
When replacing becomes the best alternative
Not all stations are suitable to be renovated. Sewer lift stations might need to be replaced if they have a severely damaged wet well, or have a low capacity for structural strength.
When making a choice, it is crucial to take into consideration the structural condition of the building, its compatibility equipment, accessibility to construction, continuity of service and the long-term requirements. Romtec Utilities begins retrofit and replacement projects by identifying which components will be retained and which require replacement.
From there, the firm creates engineering solutions that are specific to the site including preliminary designs, as well as budgetary estimates. Prefabricated components can also help organize installation and reduce some on-site construction requirements.
The Project Doesn’t End When the Pumps Are Running
The modern lift station must operate as a system. Before returning it to regular maintenance, initial testing and commissioning helps ensure that the pumps, controls and other equipment are operating according to the specifications of the design.
Manuals as well as training for operators are equally crucial. Before taking on the responsibility of a station, maintenance personnel must understand the latest equipment, procedures, and documents.
Retrofitting infrastructure effectively preserves its value, while also addressing limitations that led to modernization.
For municipal facilities and facility owners, that means looking beyond the immediate repair. The most effective project is one that integrates new equipment into existing structures, maintains essential service throughout construction and also prepares the pumping system to last for years of continuous operation.