A municipality has an aging wastewater lift station. Pumps are about to expire their usefulness, the controls need to be modernized and the access hatch must be replaced. The concrete wet well is sturdy and solid.
Do you think the station should be completely demolished? Not necessarily. The better question to ask is whether the existing infrastructure can support an efficient pumping system that is in line with modern standards without compromising reliability and capacity.
Image credit: romtecutilities.com
A carefully engineered pump station retrofit can preserve valuable infrastructure while replacing components that no longer meet operational requirements.
Begin with the Structure that nobody wants to replace.
Wet wells can be the most expensive and difficult element to replace because they are submerged and linked to existing pipes, and essential for wastewater collection.
Retaining the concrete structure may decrease excavation and construction work.
However, deterioration near the access hatch may complicate your decision. Romtec Utilities says that wet well hatches can be replaced in retrofits. Instead of affixing a hatch to deteriorated cement replacing the whole top layer can be a more durable option. This technique can be utilized to increase access and improve the functionality of the structure, without the need to replace the entire wet well.
A more powerful pump alters the Engineering
Imagine a neighborhood that has seen an increase in population since its first lift station was built. It’s possible that the existing pumps are no longer capable of handling the increased water flow.
Pumps that have higher horsepower can be used to improve a pumping station, but the equipment must also fit within the system. To get more powerful pumps you might need change the discharge elbows or pipe. You may also need to replace electrical controls or valves.
Engineers must also consider the requirements of the hydraulic system, including the head of flow and total dynamic head. If you install a bigger pump without evaluating these conditions, it can cause operational problems rather than resolve them. Planning future capacity in the initial design makes later expansion much easier.
Make sure that the wastewater is kept moving during Construction
Retrofitting a wastewater pump station presents a unique challenge, which isn’t faced by other projects. The station may have to be operational for the duration of construction.
Even when contractors are working and preparing for the next project, wastewater is still arriving. Depending on the project, temporary bypass pumping may be necessary to keep operation while the old equipment is removed and new equipment is installed.
Romtec Utilities embraced this difficult task at the Federal Law Enforcement Training Center, Brunswick, Georgia.
The project required the replacement of two aging wastewater lifting stations, whilst maintaining the operation at the facility. Site-specific engineering, packaged replacement systems, and bypass pumping strategies were used to adapt to the existing station footprints as well as operational demands. This example shows the importance of focusing on construction sequencing prior to installation.
In the event that replacement is not an option, it’s the best option
It is not possible for every station to be renovated. Sewer lift stations might have to be rebuilt in the event of a badly damaged wet well or a lack of capacity for structural strength.
The selection should consider structural health, equipment compatibility, construction access along with service continuity as well as long-term requirements for operation. Romtec Utilities starts retrofitting and replacing projects by identifying elements that will remain and those that will need to be replaced.
The company also develops engineering solutions specifically for the location, including preliminary designs and budget estimates. Prefabricated components are also beneficial to organize installation and reduce certain on-site demands.
The Project Isn’t Complete When the Pumps Are Beginning
A modernized lift station must be able to function as an integrated system. Prior to returning the lift station back to service, testing the startup and commissioning will help ensure that the pumps, control equipment and other components are performing according to approved design.
Training for operators and maintenance and operation manuals are equally important. Maintenance personnel must be familiar with new equipment and operating procedures, and the documents before taking responsibility for the station.
A successful retrofit will preserve the infrastructure and addresses the issues that required modernization.
For facility owners and municipalities this means looking beyond immediate repairs. The most successful initiatives are those that incorporate new equipment into existing structures, and maintain essential service during construction. They also make preparations for the pumping system so that it can continue running for a long time.