A municipality is home to an aging wastewater lift station. The pumps are coming to the end of their useful lifespan, the controls require modernization, and the access hatch has deteriorated. Although the concrete wetwell appears solid structurally, it requires to be modernized.
Image credit: romtecutilities.com
Should the station be demolished? Not necessarily. The most important question is whether the existing infrastructure will be able to accommodate a modern pumping system, without compromising the reliability, accessibility to maintenance and capacity.
Retrofitting a pump station could be a great way to maintain infrastructure, and also replace parts that are no longer functioning.
Start with the structure nobody wants to replace.
The wet well is often among the most expensive and challenging components to replace because it is submerged, connected to existing piping, and vital to the process of removing wastewater.
Retaining a concrete construction that is still serviceable can reduce the excavation and construction.
But, any deterioration in the vicinity of the access hatch may complicate your choice. Romtec Utilities identifies wet well hatch replacement as a standard retrofit requirement. Instead of affixing a hatch to cement that is deteriorating, replacing the entire top layer can be a better option. This approach can improve access and extend the structure’s usefulness without having to rebuild the entire wet well.
A More Powerful Pump Modifies the Engineering
Take a look at a neighborhood that has experienced significant increase since the opening of its lift station. The current pumps might not be sufficient to handle the increased flow of wastewater.
Pumps with more horsepower may be used to upgrade an existing pumping station, however the equipment needs to fit into the system. Pumps that have higher horsepower might require adjustments to discharge elbows and piping along with electrical controls, valves, and other parts.
The engineers should also take into consideration the hydraulic requirements of the system, such as flow rate and dynamic head total. Installing a larger pump without reviewing these conditions can create operational issues rather than solving them. The planning for future expansions at the time of initial design will enable you to build later.
Keep Wastewater Moving during Construction
A wastewater pump station retrofit introduces a challenge that ordinary equipment replacement projects may not face: the station may need to remain operational throughout construction.
Contractors continue to work and wastewater continues to come in. According to the study an interim bypass pumping system may be needed to keep service running while the existing equipment is taken down or new equipment is installed.
Romtec Utilities was able to address this kind of challenge at the Federal Law Enforcement Training Center in Brunswick, Georgia.
The project involved replacing two wastewater lift stations that were in poor condition while also maintaining the operation of the facility. The project was able adapt to the existing footprints of stations as well in operational requirements, using local-specific engineering and packaged replacement systems. The example illustrates the importance of focusing on construction sequencing prior to the installation process begins.
When replacement is the better option
Some stations may not be suitable for rehabilitation. Sewer lift stations might have to be rebuilt when they have a seriously damaged wet well, or have a low structural capacity.
In making a decision, it is crucial to take into consideration the structural integrity of the building, its compatibility equipment, the accessibility to construction sites, service continuity and long-term needs. Romtec Utilities begins retrofits and replacements by identifying components which are expected to stay and those which need replacement.
From there, the company creates engineering solutions that are specific to the site as well as preliminary designs and budgetary estimates. Prefabricated parts are also helpful to organize installation and reduce the number of on-site requirements.
The Project Isn’t Complete until the Pumps are Beginning
A modern lift station should operate as an integrated system. Before returning the lift station to service, startup tests and commissioning are a way to make sure that the pumps, control equipment and other components work in accordance with approved design.
Training and manuals for operators are equally important. Prior to taking over the responsibility of the maintenance of a station, employees should be familiar with the latest equipment, procedures, and also the documents.
An effective retrofit will preserve infrastructure that still has value while addressing the issues that made modernization necessary.
This means that municipalities and facility owners need to consider more than just immediate repairs. The most successful projects combine the latest equipment with the existing structures. They maintain essential services while construction is underway and then prepare the pumping systems for years of continuous operation.