A deteriorating wastewater liftstation is situated in a municipality. The pumps are nearing the end of their service life, and the controls require modernization and the access hatch is deteriorating. However, the concrete wet well remains structurally sound.

Should the station be destroyed? Not necessarily. One of the most important questions to ask is whether or not the current infrastructure can support pumps that meet the latest 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 Structures Nobody Will Want to Replace

The wet well can be one of the most costly and disruptive parts to replace as it is buried, connected to existing piping, and essential to wastewater collection.

If the concrete structure is usable, its retention could minimize excavation and construction work.

However, deterioration around the access hatch can make the process. Romtec Utilities says that wet well hatches are typically replaced as part of retrofits. Instead of attaching the hatch to cement that is deteriorating, replacing the entire top layer can be a better option. This approach can be employed to improve access and the structure’s usability without the need for rebuilding the whole wet well.

An improved pump can alter the design

Imagine that the area of residence has increased significantly since the initial lift station installation. It’s possible that the existing pumps are no longer sufficient to handle the increasing wastewater flow.

A pumping station upgrade could be accompanied by higher horsepower pumps. However, the choice of equipment cannot be made independently of the rest of the system. Pumps that have higher horsepower might require adjustments to discharge elbows and piping and electronic controls, valves and other components.

The engineers should also take into consideration the hydraulic requirements of the system, which includes the flow rate as well as the dynamic head total. Installing a larger pump without reviewing these conditions can create problems with operation rather than addressing these. Planning future capacity prior to initial design makes future expansion easy.

Keep the Wastewater Moving During Construction

A wastewater pump station retrofit introduces a challenge that ordinary construction projects for new equipment do not encounter: the facility may require operation through the entire construction.

Contractors continue to work, and wastewater will still arrive. According to the project an interim bypass pumping system could be required to sustain service while the existing equipment is taken down or new components are added.

Romtec Utilities was able to take on this difficult task at the Federal Law Enforcement Training Center, Brunswick, Georgia.

The project required the replacement of two older wastewater lifting stations while maintaining the operation at the facility. The project was able accommodate the existing footprints of stations as well as operational requirements by using customized engineering on site and integrated replacement systems. The case study illustrates why construction sequencing deserves attention before the construction process starts.

In the event that replacement is not an option, it’s the best option, replace it.

Not all stations are suitable to be renovated. If the sewer lift station requires replacement because of a damaged well, structural constraints or significant changes in the needs for hydraulics, it may be more appropriate to replace the station rather than alter.

The selection should consider structural health, equipment compatibility accessibility to construction along with service continuity and long-term operating requirements. Romtec Utilities starts retrofitting and replacing projects by identifying the components that will be retained as well as those that require to be replaced.

The company then develops engineering solutions that are specific to the location, including preliminary plans as well as budget estimations. Prefabricated parts can also help with installation and can reduce construction-related requirements on site.

The Project Isn’t Fully Complete Until the Pumps are Started

The modern lift station needs to operate as a system. Before returning a lift-station to normal service, start-up tests, commissioning as well as verification of equipment are required to verify that the pumps, controls and equipment work as designed.

Operator training, as well as operation and maintenance manuals are equally crucial. Maintenance personnel should be familiar with the latest equipment as well as operating procedures, and the documents before taking responsibility for the station.

Retrofitting infrastructure successfully preserves its value, while addressing limitations that led to modernization.

Municipalities and property owners have to be aware of the need for more than just immediate repairs. The strongest project is one that integrates new equipment with existing structures, keeps up with essential service during construction and also prepares the pumping system to last for years to come of operation.