The sewer lift station in an urban municipality is old. The pumps are nearing the end of their service life, and the controls require modernization, as well as the access hatch is deteriorating. The concrete wet well is robust and sturdy.
Should the entire station be demolished and rebuilt? Not necessarily. The best question to ask is whether the existing infrastructure will support pumps that meet current standards without compromising reliability and future capacity.
Image credit: romtecutilities.com
A carefully engineered pump station retrofit can preserve valuable infrastructure while replacing components that no longer meet operational requirements.
Start with the structure that nobody wants to replace.
Wet wells are typically the most costly and disruptive element to replace because they are constructed underground and attached to pipes that are already in place, and crucial to the process of removing wastewater.
If the concrete structure remains in good condition, retaining it could minimize excavation and construction work.
The loss of space around the access hatch might cause problems with this decision. Romtec Utilities identifies wet well hatch replacement as a standard retrofit requirement. Rather than attaching a new hatch to concrete that is deteriorating or replacing the entire top layer could provide a more durable solution. This could increase the accessibility to the structure and prolong its lifespan, without needing to rebuild the entire wet well.
The development of an even more powerful pump is different
Imagine that a residential area has exploded in size since the original lift station installation. It’s possible that current pumps are not able to handle increased the flow of wastewater.
Pumps with more horsepower may be used to improve the pumping station, however the equipment has to be integrated within the system. Pumps with greater power may require modifications to elbows for discharge, pipes, valves, electrical controls and other elements.
Engineers should also evaluate the requirements for hydraulics of the system, which includes flow rate and dynamic head total. A larger pump prior to assessing the requirements could create more problems than it resolves. Planning for future capacity when you are making the initial design process can allow for later expansion much more easily.
Keep Wastewater Moving during Construction
Retrofitting an existing wastewater pump station could be the challenge of a completely new one. Unlike other equipment replacement projects, the station will require continued operation during construction.
Even if contractors are busy and preparing for the next project, wastewater is still arriving. In the case of a project, temporary bypass pumping may be required to maintain operation while the existing equipment is removed and new equipment is installed.
Romtec Utilities was able to address this kind of challenge at the Federal Law Enforcement Training Center in Brunswick, Georgia.
The project involved the replacement of two old wastewater lift stations as well as maintaining the operation at the facility. The site-specific engineering, packaged systems and bypass pumping techniques helped accommodate existing station footprints as well as operational needs. This is a good example of the reasons why the sequence of construction is important to consider prior to installation.
In the event that replacement is not an option, it’s the best option
Not all stations are suited for rehabilitation. Sewer lift stations may need to be rebuilt in the event of a badly damaged or insufficiently functioning wet well. structural capacity.
The decision must take into consideration structural integrity, equipment compatibility construction access along with service continuity and long-term operational requirements. Romtec Utilities begins retrofits and replacements by identifying elements to be left in place and the ones that require replacement.
From there, the firm creates engineering solutions for specific sites as well as preliminary designs and budgetary estimates. Prefabricated components can be useful in arranging installation and decreasing the number of on-site requirements.
The work isn’t done until the pumps begin to run.
The modernized lift station should function as a complete system. Prior to returning the lift station to service, testing the startup and commissioning will help ensure that the pumps, controls as well as other equipment are performing according to approved design.
Maintenance and operation manuals along with training of operators, are vital. Before taking on the responsibility of an entire station, the personnel in charge of maintenance should be familiar with new procedures, equipment and also the documents.
An effective retrofit will preserve structures that are still useful while addressing the issues which led to the need for modernization.
For facilities owners and municipal authorities this means looking beyond immediate repairs. The strongest project is one that integrates new equipment into existing structures, provides essential service during construction, and then prepares the pumping system to last for years of continued operation.