A disused wastewater liftstation can be located in a municipality. The pumps are coming to the end of their useful lifespan, the controls require modernization, as well as the access hatch is deteriorating. Even though the concrete wetwell is structurally sound, it needs to be upgraded.
Do you think the station should be destroyed and rebuilt? Not necessarily. One of the most important questions to consider is whether the current infrastructure will be able to support the pumping system of the latest standards, without compromising reliability and capacity.
Image credit: romtecutilities.com
A well-designed retrofit to a pump station will help protect valuable infrastructure while replacing components which no longer meet the operational standards.
Start with the structure nobody wants to replace.
Wet wells can be the most costly and disruptive component to replace as they are buried and connected to existing pipes and are crucial to the process of removing wastewater.
Retaining the concrete structure could reduce excavation work and construction.
However, deterioration around the access hatch may complicate the decision. Romtec Utilities says that wet well hatches are typically replaced in retrofits. Instead of attaching a hatch to deteriorated cement replacing the whole top layer can be a more reliable option. This technique can be utilized to improve access and the usability of the structure without needing to rebuild the entire wet well.
A More Powerful Pump Modifies the Engineering
Consider a neighborhood that has experienced significant increase since the opening of the lift station. The existing pumps might not be able to deal with the increased flow of wastewater.
A pumping station upgrade could involve higher-horsepower pumps, but equipment selection cannot happen independently of the surrounding system.
Engineers must also evaluate the requirements of the hydraulic system, including flow and total dynamic head. If you add a larger pump without evaluating these conditions it could create operational problems rather than resolve them. Planning future capacity at the time of initial design can make future expansion easy.
Keep Wastewater Moving during Construction
Retrofitting a wastewater pumping station presents a unique challenge, that is not encountered in other construction projects. The station could need to be operational while construction is underway.
Even when contractors are working. According to the plan it is possible that a temporary bypass pumping system is needed to keep service running while the existing equipment is taken down or new components are added.
Romtec Utilities was able to take on this challenge at the Federal Law Enforcement Training Center, Brunswick, Georgia.
The project included replacing two older wastewater lift stations and ensuring the operations of the facility. Site-specific engineering and packaged replacement systems and bypass pumping techniques helped adapt to the existing station footprints and operational requirements. The case study illustrates the importance of focusing on construction sequencing before installation begins.
When replacing is the most efficient option
Not every station can be rehabilitated. A badly degraded wet-well insufficient structural capacity or significant changes to the hydraulic requirements can make the replacement of a sewer lift station more appropriate than modifying the existing system.
The decision should account for the condition of the structure, compatibility with equipment access to construction to the site, service continuity, and long-term operating needs. Romtec Utilities starts retrofitting and replacing projects by identifying components that are to be kept and those that will need to be replaced.
The company develops site-specific engineering solutions initial designs, as well as budgetary estimates. Prefabricated components help organize installation, and reduce the amount of construction work that is required on site.
The project won’t be finished until the pumps kick in
Modern lift stations have to be operated as an integrated system. Prior to returning it back to regular service, startup testing and commissioning helps ensure that the controls, pumps, and other equipment are operating according to the approved design.
Training and manuals for operators are equally important. Prior to taking over the responsibility of a station, maintenance personnel must understand the latest equipment, procedures and the documentation.
Retrofitting infrastructure can preserve its value while solving the shortcomings that led to modernization.
For facility owners and municipalities it is important to look beyond the immediate repair. The most successful projects combine new equipment and existing structures. They provide essential services during construction and prepare the pumping systems to last for a long time.