A decrepit wastewater liftstation is situated in a municipality. The pumps are nearing the final stage of their life and the controls are dated as well as the access hatch is degraded. The concrete wet well is solid and structurally sound.
Do you think the station should be completely demolished and rebuilt? Not necessarily. The more important question to consider is whether or not the current infrastructure will support 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 that nobody is Trying to Replace.
The wet well is usually one of the more expensive and challenging components to replace since it is submerged, connected to existing piping and is essential to wastewater collection.
The retention of a concrete structure that is still serviceable can minimize the digging and construction.
The degradation of the area around the access hatch could complicate this decision. Romtec Utilities identifies wet well hatch replacement as a common retrofit requirement. Instead of attaching a brand new hatch to a damaged concrete structure replacement of the entire top slab might make a more robust solution. This will allow for greater access to the structure and extend its use, without the need to replace the entire structure as well.
An improved pump changes the design
Think about a community that has seen a substantial increase in population since the construction of its lift station. It could be that the current pumps are not adequate to handle the increase in wastewater flow.
Pumps with more horsepower may be used to improve a pumping station, but the equipment should also be incorporated into the system. For pumps that are more powerful you might need make adjustments to the discharge elbows or piping. You may also need to alter electrical controls and valves.
Engineers should also consider the hydraulic requirements of the system. This is a consideration for flow as well as total dynamic pressure. If you add a larger pump and do not consider these aspects this could result in problems in operation instead of resolving the problem. Planning future capacity in the initial design can make future expansion much easier.
Keep Wastewater Moving during Construction
A retrofit of a wastewater pumping station creates a challenge that regular project for replacement of equipment may not encounter: the facility may need to remain operational during construction.
Even when contractors are busy they continue to receive wastewater. According to the plan the project, a temporary bypass pumping system is necessary to maintain service as the existing equipment is taken down or new components installed.
Romtec Utilities was able to address this kind of problem at the Federal Law Enforcement Training Center in Brunswick, Georgia.
The project involved replacing two old wastewater lift stations and ensuring the operations of the facility. The project was able to adapt to existing station footprints as in operational requirements, using specific engineering for the site and system for replacement that is packaged. The case study illustrates why the sequence of construction should be considered before installation begins.
When the Alternative is the Best Choice
It is not possible for every station to be renovated. If the sewer lift station is in need of a replacement because of a severely degraded well, structural issues or significant changes in hydraulic requirements, it might be more appropriate to replace the station rather than alter.
In making a final decision, it is important to consider the structural integrity of the structure, its compatibility to equipment, the accessibility to construction, the continuity of services and long-term needs. Romtec Utilities begins retrofits and replacements by identifying parts to be left in place and those which need replacement.
The company develops engineering solutions specifically for the site, preliminary designs as well as budget estimations. Prefabricated components are also beneficial in arranging installation and decreasing certain on-site demands.
The project won’t be finished until the pumps start
Modernized lift stations should be able to function as an integrated system. Prior to returning a lift station to normal operation, initial tests, commissioning as well as verification of the equipment are essential to ensure that all pumps, control systems, and other equipment are operating according to design.
Training for operators and maintenance and operation manuals are equally important. Prior to taking over the responsibility of an entire station, the personnel in charge of maintenance should be familiar with new procedures, equipment and the documentation.
A successful retrofit helps preserve infrastructure that still has value while addressing the issues that led to modernization being necessary.
For municipal facilities and facility owners This means looking beyond the immediate repair. The most successful projects incorporate new equipment into existing structures, and continue to provide essential services while construction is underway. Also, they prepare the pumping system to keep operation for many years.