The municipality has an old wastewater lift station. Pumps are advancing towards the end of their useful life, while controls need modernization and the access hatch needs to be replaced. However, the concrete wet well remains solid and sturdy.
Should the entire station be demolished and rebuilt? Not necessarily. It is important to determine if the infrastructure already in place is capable of supporting the modern pumping system without compromising capacity in the future and reliability or maintenance access.
Image credit: romtecutilities.com
A well-engineered retrofit of the pump station could preserve the infrastructure’s value while replacing parts which no longer meet the functional requirements.
Begin with the Structures No One Wants To Replace
The wet well can be one of the most costly and challenging components to replace, as it’s hidden, connected to the existing piping and is essential for wastewater collection.
If the concrete structure is serviceable, retaining it may reduce excavation and construction work.
However, deterioration near the access hatch could affect your choice. Romtec Utilities identifies wet well hatch replacement as a standard retrofit requirement. Rather than attaching a new hatch to a damaged concrete structure, replacing the entire top layer could make a more robust solution. This could increase the accessibility to the structure and prolong its usefulness, without having to replace the entire structure as well.
A more powerful pump alters the Engineering
Let’s say a residential area has seen an increase in population since its first lift station was built. The existing pumps might not be able to deal with increased wastewater flows.
A pumping station upgrade could involve higher-horsepower pumps, but equipment selection cannot happen independently of the surrounding system.
Engineers should also assess the system’s hydraulic requirements including the flow and head total dynamic. Installation of a larger pump without evaluating the situation could cause more problems than it solves. Planning for future capacity during the initial design stage can help later expansions to be much easier.
Make sure that the Wastewater is moved during Construction
Retrofitting a wastewater pump station can be the challenge of a completely new one. As with other equipment replacement projects, the station will need to continue operating during construction.
Even if contractors are busy and preparing for the next project, wastewater is still arriving. Based on the nature of the project an interim bypass pumping system may be required to keep operation while the existing equipment is taken away and new components are installed.
Romtec Utilities accepted this challenge in the Federal Law Enforcement Training Center, Brunswick, Georgia.
The project involved replacing two older wastewater lifting stations while maintaining operation at this facility. The project was able to accommodate the footprints of existing stations as well in operational requirements, using local-specific engineering and modular replacement systems. This example shows how important it is to take into consideration the sequence of construction prior to installing.
If replacement is the best alternative
It is not possible for every station to be renovated. If the sewer lift station requires replacement because of a severely degraded well, structural problems or significant changes to the hydraulic requirements, it could be better to replace instead of modify.
Before making a decision it is crucial to look at the structural integrity of the structure, its compatibility to equipment, the accessibility to construction, the continuity of services as well as long-term requirements. Romtec Utilities begins retrofits and replacements by identifying components that are to remain and those which need replacement.
The company develops engineering solutions that are specific to the site, preliminary designs and budget estimates. Prefabricated components help simplify installation and decrease the amount of construction work that is required on site.
The Project Isn’t Finished When the Pumps Start
Modern lift stations must work as a complete system. Prior to returning the lift station to service, testing the startup and commissioning can help to ensure that the pumps, control equipment and other components are operating in accordance with the approved design.
Operator training and operation and maintenance manuals are equally crucial. Prior to taking over the responsibility of a station, maintenance personnel must understand new procedures, equipment and also the documents.
Retrofitting successfully preserves the value of infrastructure while addressing the limitations which led to the need for modernization.
For facility owners and municipalities this means looking beyond immediate repairs. The best projects incorporate new equipment into existing structures to ensure that essential service is maintained while construction is underway. Also, they prepare the pumping system for continued in operation for a number of years.