An aging wastewater liftstation is located in a municipal. Pumps are nearing the end of their usefulness, the controls need to be modernized and the access hatch should be replaced. The concrete wet well is solid and structurally sound.
Should the entire station be demolished and rebuilt? Not necessarily. The most important question is whether the current infrastructure can support a modern pumping system, without compromising security, maintenance access and capacity.
Image credit: romtecutilities.com
Retrofitting a pump station could be a fantastic method to save infrastructure and replace parts that have become obsolete.
Begin with the structure no one wants to replace
It’s expensive and time-consuming to replace the wet-well since it is submerged beneath the earth, and is connected to pipes and essential to collect wastewater.
Retaining a concrete construction which is still functional could help in reducing the excavation and construction.
However, the deterioration of the access hatch can complicate the process. Romtec Utilities identifies wet well hatch replacement as an usual retrofit requirement. Instead of gluing a hatch to deteriorated cement, replacing the whole top layer may be a more reliable option. This can increase access to the structure, and extend its utility, without having to rebuild the entire wet well.
The design of the pump with more power is different
Imagine a place that has seen a significant increase in population from the time of the first lift station installation. It is possible that the current pumps are not able to handle increased flows of wastewater.
An upgrade to the pumping station could require higher horsepower pumps, but equipment selection cannot happen independently of the surrounding system. For pumps that are more powerful, you may need modify the discharge elbows or the piping. You might also have to replace electrical controls or valves.
The engineers must also assess the requirements for hydraulics of the system, which includes the flow rate as well as the dynamic head total. The installation of a bigger pump without checking these parameters can cause problems in operation instead of resolving the issues. The planning of future capacity at the initial design process can help later expansions to be much easier.
Make sure that the waste water is flowing during construction
Retrofitting a wastewater pumping station is a particular challenge which isn’t faced by other projects. The station might need to be operational during construction.
Contractors continue to work, and wastewater will still arrive. Depending on the scope of the project temporary bypass pumps might be needed to maintain service during removal and installation of existing equipment.
Romtec Utilities took on this kind of challenge in the Federal Law Enforcement Training Center in Brunswick, Georgia.
The project involved the replacement of two wastewater lift stations that were in use as well as maintaining the operation at the facility. The project was able adapt to existing station footprints as well as operational requirements by using customized engineering on site and modular replacement systems. This illustrates why the construction sequence should be considered prior to installation.
When replacing is the most efficient option
Some stations may not be suited to be renovated. 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.
When making a choice, it is crucial to take into consideration the structural condition of the building, its compatibility with equipment, access to construction, service continuity and long-term requirements. Romtec Utilities begins retrofits and replacements by identifying elements to be left in place and the ones that require replacement.
The company can then design engineering solutions specific to the site, preliminary plans as well as budget estimations. Prefabricated components are also beneficial to facilitate installation and reduce some on-site requirements.
The project won’t be finished until the pumps are turned on
The modernized lift station should work as a whole. Prior to returning it back for regular maintenance, start-up testing and commissioning helps ensure that the pumps, controls, and associated equipment perform according to the established design.
Training and manuals for operators are equally essential. Before taking on the responsibility of a station, maintenance personnel must be aware of the latest equipment, procedures and the documentation.
Retrofitting successfully preserves the infrastructure and addresses the issues that led to the need for modernization.
Municipalities and facility owners must consider more than immediate repairs. The best initiatives are those that incorporate new equipment into existing structures, and continue to provide essential services during construction. They also make preparations for the pumping system to continue in operation for a number of years.