A deteriorating wastewater liftstation is located in a municipality. The pumps are nearing the end of their life expectancy and the controls are inefficient, and the access hatch is worn out. The concrete wet well is solid and structurally sound.
Image credit: romtecutilities.com
Do you think the station should be destroyed and rebuilt? Not necessarily. The more useful question is whether the current infrastructure will be able to accommodate a modern pumping system, without compromising reliability, maintenance access and capacity.
A well-designed retrofit to a pump station will help protect important infrastructure and replace components that no longer meet functional requirements.
Start with the Structure That No One wants to replace.
It’s costly and inconvenient to replace the wet-well because it is buried in the ground and connected to pipes, and is necessary for wastewater collection.
Retaining a concrete structure that is functional can make it easier to dig and build.
The degradation of the area around the access hatch could complicate this decision. Romtec Utilities says that wet well hatches are typically replaced in retrofits. Instead of attaching a hatch to deteriorated cement replacing the whole top layer can be more durable. This could increase the accessibility to the structure, and extend its lifespan, without needing to completely rebuild the wet well.
The technology behind pumps that are more powerful is different
Let’s say a residential area has seen an increase in population since its first lift station was built. Existing pumps may not be able to deal with the increased flow of wastewater.
Pumps that have higher horsepower can be used to upgrade the pumping station, however the equipment needs to fit within the system. Pumps with greater horsepower could require modifications to discharge elbows, piping and pipework along with electronic controls, valves and other parts.
Engineers must also evaluate the system’s hydraulic requirements, including flow and total dynamic head. Installing a larger pump without considering the circumstances could create more problems than it solves. The planning of future capacity at the initial design phase can make later expansion considerably easier.
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.
Even when contractors are busy, wastewater continues to arrive. Based on the nature of the project it is possible that temporary bypass pumps will be necessary to ensure operation while the old equipment is removed and new components are installed.
Romtec Utilities fought this kind of challenge at the Federal Law Enforcement Training Center located in Brunswick, Georgia.
The project involved replacing two old wastewater lift stations and ensuring the operation at the facility. The site-specific engineering, packaged systems and bypass pumping techniques were used to accommodate existing station footprints and operational requirements. This is a good example of how important it is to take into consideration the sequence of construction prior to constructing.
In the event that replacing becomes the best option
Some stations may not be suited for rehabilitation. Sewer lift stations might need to be replaced in the event of a badly damaged wet well or a lack of capacity for structural strength.
It is important that the decision made takes into consideration structural requirements the compatibility of equipment and accessibility to construction as well longer-term operational requirements. Romtec Utilities begins retrofits and replacements by identifying elements that will remain as well as those that need to be replaced.
From there, the company develops site-specific engineering solutions as well as preliminary designs and budgetary estimates. Prefabricated components are also able to help organize installation and reduce some on-site construction requirements.
The Project isn’t Over Until the Pumps Start
Modern lift stations should be operated as an integrated system. Before returning the lift station to service, startup tests and commissioning are a way to make sure that the pumps, controls and other equipment perform as per the established specifications.
Both manuals and training for operators are equally crucial. Maintenance personnel must be familiar with the latest equipment as well as operational procedures, as well as the necessary documentation prior to taking charge of the station.
A successful retrofit helps preserve the infrastructure while also addressing the issues that required modernization.
For municipalities and facility owners This means looking beyond the immediate repair. The most successful project is one that integrates the new equipment into existing structures, ensures vital services throughout construction, and also prepares the pumping system to last for years of continued operation.