The wastewater lift station in a municipality is old. The pumps are at the limit of their lifespan and the controls are dated, and the access hatch has degraded. While the concrete wetwell is solid in its structure, it is in need of to be updated.
Do you think the station should be completely demolished and rebuilt? Not necessarily. The more important issue is whether the infrastructure in place will be able to accommodate a modern pumping system without compromising the reliability, accessibility to maintenance or future capacity.
Image credit: romtecutilities.com
A well-designed retrofit to a pump station will help protect important infrastructure and replace components that are no longer in compliance with functional requirements.
Start with the Structure That No One is Trying to Replace.
The wet well is usually one of the more expensive and disruptive components to replace because it is hidden, connected to the existing piping, and vital for wastewater collection.
If the concrete structure remains serviceable, retaining it may minimize excavation and construction work.
The degradation of the area surrounding the access hatch may complicate this decision. Romtec Utilities identifies wet well hatch replacement as a common retrofit requirement. Instead of attaching a hatch to cement that has deteriorated replacing the whole top layer can be a better option. This method can be used to increase access and improve the usability of the structure without the need to replace the whole wet well.
A Powerful Pump Changes the Engineering
Suppose a residential neighborhood has seen an increase in population since its initial lift station was constructed. It could be that the existing pumps are no longer sufficient to handle the increasing the flow of wastewater.
The upgrade of a pumping system could comprise higher horsepower equipment, but this can’t be accomplished without considering the surrounding system. For more powerful pumps it is possible make adjustments to the discharge elbows or piping. You might also have to replace electrical controls or valves.
Engineers must also consider the requirements for hydraulics of the system, such as the rate of flow and the dynamic head total. Installing a larger pump without evaluating the situation could cause more problems than it resolves. Making plans for future capacity in the initial design stage can help later expansions to be much easier.
Keep waste water moving during construction
Retrofitting an existing wastewater pump station can be challenges that are new. As with other equipment replacement projects, this one will have to remain operational for the duration of construction.
It is still a problem for wastewater to enter the system even when contractors are working. According to the plan, a temporary bypass pumping system may be required to sustain service while the equipment that is in use is removed or new equipment is installed.
Romtec Utilities tackled this type of challenge in the Federal Law Enforcement Training Center at Brunswick, Georgia.
The project required the replacement of two older wastewater lifting stations while operating the facility. The project was able adapt to the footprints of existing stations as well in operational requirements, using local-specific engineering and modular replacement systems. This is a good example of how important it is to look at the construction process prior to constructing.
If you think replacement is the better alternative, then replacement is the best
Not all stations are 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.
The decision should account for structural health, equipment compatibility accessibility to construction, service continuity, and long-term operating needs. Romtec Utilities begins retrofit and replacement projects by identifying which components will be left and which require replacement.
The company will then create specific engineering plans for the site along with budget estimates as well as preliminary designs. Prefabricated components can also help organize installation and reduce some building requirements that are required on-site.
The Project Doesn’t End When the Pumps Begin to Run
The modern lift station needs to function as a complete system. Before returning a lift-station to normal operation, initial testing, commissioning, and verification of equipment are required to make sure that all pumps, control systems, and equipment work in accordance with their design.
Both manuals and training for operators are equally crucial. Before taking on the responsibility of the maintenance of a station, employees should be familiar with the latest equipment, procedures and documents.
Retrofitting successfully preserves structures that are still useful as well as addressing the weaknesses that led to modernization being necessary.
For municipalities and facility owners it is important to look beyond immediate repairs. The most successful projects incorporate new equipment into existing structures. They ensure essential services during construction and also prepare the pumping systems to run for many years.