A decrepit wastewater liftstation is situated in a municipality. Pumps are advancing towards the end of their service life, and controls need modernization and the access hatch has to be replaced. But the concrete wet well remains robust and solid.
Do you think the station should be completely demolished? Not necessarily. The best question to ask is whether or not the current infrastructure can accommodate an efficient pumping system that is in line with current 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 nobody wants to replace.
It’s expensive and difficult to replace the wet well since it is submerged in the ground and connected to pipes, and is necessary to collect wastewater.
The retention of a concrete structure which is still functional could help in reducing the excavation and construction.
However, the deterioration around the access hatch may complicate your decision. Romtec Utilities says that wet well hatches are usually replaced in retrofits. Instead of attaching the hatch to deteriorated cement replacing the whole top layer could be a more durable option. This could improve access to the structure and prolong its lifespan, without needing to replace the entire structure as well.
A new pump improves the way engineers work.
Imagine a place that has increased significantly since the lift station’s initial installation. The existing pumps might not be able with increased wastewater flows.
Pumps with greater horsepower can be used to improve the pumping station, however the equipment must also fit into the system. Pumps with greater power may need adjustments to elbows for discharge, piping, valves, electrical controls as well as other components.
Engineers must also consider the requirements of the hydraulic system, including flow and total dynamic head. The installation of a bigger pump without checking these parameters can cause operational issues rather than solving the issues. Planning for future capacity when you are making the initial design process can allow for later expansion much more easily.
Make sure that the water for waste is flowing during construction
Retrofitting a pump station for wastewater presents a unique challenge, that isn’t encountered by other construction projects. The station may need to be operational while construction is underway.
It is still a problem for wastewater to enter the system even when contractors are in the process of working. Depending on the scope of the project temporary bypass pumps might be needed to maintain services during removal and the installation of existing equipment.
Romtec Utilities took on this kind of challenge in the Federal Law Enforcement Training Center located in Brunswick, Georgia.
The project involved the replacement of two aging wastewater lift stations, while operating the facility. Site-specific engineering packaging systems, packaged systems and bypass pumping techniques were used to accommodate existing station footprints as well as operational requirements. This is a good example of the importance of taking time to look at the construction process before constructing.
When replacing becomes the best alternative
It is not possible for every station to be restored. If the sewer lift station is in need of replacement because of a damaged well, structural issues, or significant changes in hydraulic requirements, it might be better to replace instead of modify.
In making a decision, it is important to consider the structural integrity of the building, its compatibility with equipment, accessibility to construction, service continuity and long-term needs. Romtec Utilities begins retrofit and replacement projects by identifying which elements will remain and which require replacement.
From there, the firm designs site-specific engineering solutions initial designs, as well as budgetary estimates. Prefabricated parts are also helpful in arranging installation and decreasing certain requirements on site.
The Project Doesn’t End When the Pumps Are Running
Modernized lift stations should work as a complete system. Before returning a lift-station to normal operation, initial tests, commissioning and equipment verification are necessary to make sure that the pumps, controls and the related equipment function in accordance with the specifications.
Maintenance and operation manuals along with training for operators, are vital. Maintenance staff must understand the new equipment, operating procedures, and documentation before taking responsibility for the station.
A successful retrofit helps preserve structures that are still useful while addressing the issues which led to the need for modernization.
For municipal facilities and facility owners This means looking beyond immediate repairs. The most successful projects integrate new equipment into existing structures. They provide important services during construction and set up the pumping system for a lifetime of operation.
