The sewer lift station of the municipality is old. The pumps are coming to the end of their useful life span, the controls require modernization and the access hatch is deteriorating. The concrete wet well is robust and sturdy.
Image credit: romtecutilities.com
Should the entire station be destroyed and rebuilt? Not necessarily. The best question to consider is whether or not the existing infrastructure will be able to support pumps that meet the latest standards, without compromising reliability or future capacity.
Retrofitting a pump station could be a fantastic method to protect infrastructure and replace parts which are no longer in use.
Begin with the Structures No One Would Like To Replace
The wet well is usually one of the most expensive and challenging components to replace as it is submerged, connected to existing piping and is essential for wastewater collection.
Retaining a concrete structure that is still serviceable can reduce the excavation and construction.
However, damage to the access hatch could complicate the process. Romtec Utilities identifies wet well hatch replacement as a standard retrofit requirement. Instead of attaching a hatch to cement that has deteriorated, replacing the whole top layer can be a better option. This technique can be utilized to increase access and improve the usability of the structure without having to rebuild the whole wet well.
An improved pump can alter the design
Imagine a neighborhood that has exploded in size since the original lift station installation. Pumps that are in place may not be able to deal with increased wastewater flows.
An upgrade to the pumping station could include higher horsepower pumps, however the selection of equipment is not independent of the system in which it is located. To get more powerful pumps there is a possibility that you will need to make changes to the discharge elbows, or pipes. It is also possible to change electrical controls and valves.
Engineers must also evaluate the requirements of the hydraulic system, including flow and total dynamic head. The installation of a bigger pump without considering the circumstances may cause more issues than it solves. Planning for future expansions in the initial design will allow for a much simpler process to add more capacity in the future.
Check that the waste water is flowing 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.
Contractors continue to work, and wastewater continues to come in. According to the plan, a temporary bypass pumping system could be necessary to maintain service as the equipment that is in use is removed or new components are added.
Romtec Utilities embraced this challenging task in 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 methods helped adapt to the existing station footprints and operational needs. The example illustrates why the sequence of construction should be considered before installation begins.
If replacement is the best alternative
It is not possible for every station to be repaired. A seriously degraded wet well structure that is not strong enough, or major changes in hydraulic requirements may make the replacement of a sewer lift station better than making changes to the existing structure.
In making a decision, it is crucial to take into consideration the structural condition of the structure, its compatibility to equipment, accessibility to construction, service continuity and the long-term requirements. Romtec Utilities starts retrofitting and replacing projects by identifying components that will be retained and those that must be replaced.
From there, the business develops site-specific engineering solutions including preliminary designs, as well as budgetary estimates. Prefabricated components help make installation easier and less time-consuming, as well as reduce the time spent on construction.
The project won’t be finished until the pumps kick in
The modernized lift station should function as a complete system. Before returning the lift station to service, testing its startup and commissioning are a way to make sure that the pumps, control equipment and other components are performing according to approved design.
Manuals as well as training for operators are equally vital. Maintenance staff must understand the new equipment, operating procedures, and other documentation before they take over responsibility for the station.
A successful retrofit will preserve the infrastructure and addresses the limitations which made modernization necessary.
This means that municipalities and owners of facilities need to take a look beyond the immediate fixes. The most successful projects incorporate new equipment into existing structures and keep essential services running during construction. They also prepare the pumping system for continued running for a long time.