The wastewater lift station of the municipality is old. The pumps are at the expiration date of their service life, and the controls require modernization, and the access hatch has become damaged. The concrete wet well is solid and structurally sound.
Should the entire station be demolished and rebuilt? Not necessarily. The more useful question is whether the existing infrastructure will be able to accommodate a modern pumping system, without compromising the reliability, accessibility to maintenance, or future capacity.
Image credit: romtecutilities.com
A well-designed retrofit of a pump station can help preserve the infrastructure’s value while replacing parts that no longer meet functional requirements.
Begin with the structure no one wants to replace
The wet well is usually one of the more expensive and difficult components to replace since it is submerged, connected to existing piping and is essential for wastewater collection.
If the concrete structure remains in good condition, retaining it could make it easier to dig and build.
However, deterioration around the access hatch may complicate the choice. Romtec Utilities has identified wet-well hatch replacement as a crucial retrofit. Instead of affixing a fresh hatch to concrete that is deteriorating or replacing the entire top slab could provide a more durable solution. This could improve access to the structure, and extend its usefulness, without having to replace the entire structure as well.
The engineering of a more powerful pump is different
If a neighborhood in the area has exploded in size since the initial lift station was constructed. Existing pumps may not be able with the increased flow of wastewater.
A station’s upgrade may require higher horsepower pumps, but the selection of equipment is not independent from the rest of the system. Pumps with greater horsepower may require modifications to the discharge elbows and pipes, as well as electrical controls, valves, and other components.
Engineers must also think about the hydraulic needs of the system. This includes flow and total dynamic pressure. Installation of a larger pump without considering the circumstances may cause more issues than it solves. Making plans for future capacity in the initial design stage can help later expansions to be much easier.
Keep Wastewater Moving during Construction
A retrofit of a wastewater pumping station introduces a challenge that ordinary replacement of equipment projects do not encounter: the facility could require a continuous operation throughout construction.
Contractors continue working and wastewater is still expected to arrive. According to the report, a temporary bypass pumping system might be needed to keep service running while the old equipment is removed, or new components installed.
Romtec Utilities addressed this type of problem at the Federal Law Enforcement Training Center in Brunswick, Georgia.
The project required the replacement of two old wastewater lift stations in the process of maintaining operation at the facility. The project was able to adapt to existing station footprints as in operational requirements, using customized engineering on site and packaged replacement systems. This illustrates why the construction sequence should be considered prior to installation.
If you decide to replace, it is the best Choice
Not all stations are suitable for rehabilitation. A severely deteriorated wet well, inadequate structural capacity, or major changes in hydraulic requirements may make sewer lift station replacement more appropriate than modifying the existing installation.
Before making a decision it is crucial to look at the structural condition of the structure, its compatibility with equipment, its accessibility to construction, the continuity of services and long-term requirements. Romtec Utilities begins retrofits and replacements by identifying parts that are to remain and those which need replacement.
The company can then design engineering solutions tailored to the location, initial plans as well as budget estimations. Prefabricated components can assist in simplify installation and decrease construction on site.
The project isn’t finished when the pumps kick in
Modern lift stations must operate as an integrated system. Prior to returning a lift station to normal service, startup testing, commissioning, as well as verification of equipment are required to ensure that the pumps, controls and the related equipment function in accordance with the specifications.
Manuals as well as training for operators are equally crucial. Maintenance staff must understand the latest equipment, operating procedures and documentation before taking responsibility for the station.
A successful retrofit helps preserve the infrastructure while still addressing the issues that made modernization necessary.
Municipalities and owners of facilities need to look beyond the immediate repairs. The most successful projects incorporate new equipment and existing structures. They maintain essential services while construction is underway and then prepare the pumping systems for years of continuous operation.