A disused wastewater liftstation can be located in a township. Pumps are nearing the end their useful life, while controls require modernization, and the access hatch has to be replaced. But the concrete wet well remains structurally sound.
Image credit: romtecutilities.com
Should the entire station demolished and rebuilt? Not necessarily. The more important issue is whether the current infrastructure can accommodate a new pumping system without compromising the reliability, accessibility to maintenance and capacity.
Retrofitting a pumping station can be a great way to preserve infrastructure, and also replace parts that are no longer functioning.
Begin with the Structures that nobody Will Want to Replace
The wet well is often one of the most costly and disruptive parts to replace, as it’s submerged, connected to existing piping and is essential to the collection of wastewater.
If the concrete structure is serviceable, retaining it may reduce excavation and construction work.
However, the deterioration around the access hatch can complicate the decision. Romtec Utilities identifies wet well hatch replacement as an usual retrofit requirement. Instead of affixing a fresh hatch to the deteriorated concrete or replacing the entire top slab could make a more robust solution. This will allow for greater access to the structure and prolong its usefulness, without having to completely rebuild the wet well.
The technology behind a more powerful pump is different
Imagine a place that has exploded in size since the lift station’s initial installation. Existing pumps may not be able to deal with the growing flow of wastewater.
A change to the pumping station may require higher horsepower pumps, but the choice of equipment cannot be made independently of the rest of the system. Pumps that have higher horsepower might require modifications to the elbows for discharge and piping and electrical controls, valves and other components.
Engineers should also evaluate the hydraulic requirements of the system, including the flow rate as well as the dynamic head total. A larger pump installed without studying these factors can lead to problems with operation rather than addressing these. Planning future capacity prior to designing the initial design makes expansion later easy.
Make sure that the Wastewater is moved 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 the wastewater will continue to flow. In the case of the project the temporary bypass pumps could be required in order to maintain services during removal and the installation of existing equipment.
Romtec Utilities faced this kind of challenge at the Federal Law Enforcement Training Center in Brunswick, Georgia.
The project involved the replacement of two wastewater lift stations that were in use in the meantime, and maintaining the operation of the facility. The project was able adapt to the footprints of existing stations as well in operational requirements, using site-specific engineering and integrated replacement systems. This case illustrates the importance of taking time to take into consideration the sequence of construction before installing.
If you decide to replace, it is the best Option
There are many stations that can be rehabilitated. Sewer lift stations could need to be replaced in the event of a badly damaged wet well or inadequate structural capacity.
The decision must take into consideration structural health, equipment compatibility construction access to the site, service continuity, as well as long-term requirements for operation. Romtec Utilities starts retrofitting and replacing projects by identifying components that are to be kept and those that need to be replaced.
The company also develops engineering solutions specific to the site, preliminary plans and budget estimates. Prefabricated components are also able to help facilitate installation and cut down on construction-related requirements on site.
The Project Doesn’t End When the Pumps Start
The modern lift station must work as a whole. Before returning it to regular service, startup testing and commissioning ensures that the pumps, controls and the associated equipment work according to the established design.
Manuals for operation and maintenance along with training of operators, are essential. Maintenance personnel must be familiar with the latest equipment and operating procedures, in addition to the documentation before they take charge of the station.
Retrofitting successfully preserves structures that are still useful while addressing the issues that made modernization necessary.
Municipalities and facility owners must be aware of the need for more than just immediate repairs. The most successful projects incorporate the latest equipment with the existing structures. They maintain essential services during construction and set up the pumping system to run for many years.