A municipality is home to an aging wastewater lift station. Pumps are nearing the end of their service life, and controls need modernization and the access hatch needs to be replaced. While the concrete wetwell is solid in its structure, it is in need of to be modernized.
Do you think the station should be completely destroyed? Not necessarily. It is better to inquire if the system is able to support the modern pumping system without compromising future capacity and reliability or maintenance accessibility.
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 are often the most costly and disruptive part to replace, since they are underground and connected to pipes that are already in place, and essential for wastewater collection.
A concrete structure which is still functional could make it easier to dig and build.
However, the deterioration around the hatch could complicate your choice. Romtec Utilities says that wet well hatches can be replaced in retrofits. Instead of attaching a hatch to cement that is deteriorating, replacing the entire top layer could be a more durable option. This will allow for greater access to the structure and extend its lifespan, without needing to rebuild the entire wet well.
The design of a more powerful pump is different
Imagine a neighborhood which has experienced a significant growth since the installation of a lift station. Existing pumps may not be able with the increasing flow of wastewater.
Pumps that have higher horsepower can be used to improve a pumping station, but the equipment should also be incorporated into the system. Higher horsepower pumps might need adjustments to elbows for discharge, pipes, valves, electrical controls as well as other components.
Engineers should also look at the hydraulic needs of the system. This is a consideration for flow as well as total dynamic pressure. Installation of a larger pump without considering the circumstances could create more problems than it solves. Planning future capacity prior to initial design makes later expansion significantly easier.
Make sure that the Wastewater is moved during Construction
Retrofitting a wastewater pumping station presents a unique challenge, that isn’t encountered by other projects. The station might need to be operational throughout construction.
The water continues to flow even when contractors are in the process of working. According to the type of project, temporary bypass pumping may be required to maintain operation while the existing equipment is taken away and new components are put in place.
Romtec Utilities took on this challenge at the Federal Law Enforcement Training Center, Brunswick, Georgia.
The project involved replacing two wastewater lift stations that were in poor condition in the process of maintaining operation at the facility. Specific engineering for the site packages, replacement systems for packaged equipment, and bypass pumping techniques helped accommodate the existing station footprints and operational requirements. The case study illustrates the importance of focusing on construction sequencing before the construction process starts.
When replacing is the most efficient option
Not all stations are suitable to be renovated. A seriously degraded wet well or a structural weakness or significant changes in hydraulic requirements could make an upgrade to a sewer lift station more appropriate than changing the existing structure.
Before making a decision it is crucial to look at the structural integrity of the building, its compatibility equipment, its accessibility to construction, continuity of service and the long-term requirements. Romtec Utilities starts retrofitting and replacing projects by identifying the elements that will remain and those that must be replaced.
The company then develops engineering solutions that are specific to the site, as well as preliminary plans and budget estimates. Prefabricated components are also useful to facilitate installation and reduce some on-site requirements.
The Project Isn’t Finished When the Pumps Get Started
The modern lift station must operate as a system. Before returning the lift station to service, testing its startup and commissioning are a way to make sure that the pumps, controls as well as other equipment perform as per the approved design.
Operator training and operation and maintenance manuals are equally important. Before taking on the responsibility of the maintenance of a station, employees should be familiar with new procedures, equipment and the documentation.
Retrofitting infrastructure can preserve its value, while also addressing limitations that led to modernization.
This means that municipalities and facility owners need to look beyond the immediate repairs. Most successful projects blend the latest equipment with the existing structures. They ensure essential services while construction is underway and prepare the pumping systems for a lifetime of operation.