The wastewater lift station in the municipality is old. The pumps are at the maximum lifespan and the controls are dated, and the access hatch is deteriorated. Yet the concrete wet well is solid and sturdy.
Image credit: romtecutilities.com
Should the entire station be demolished and rebuilt? Not necessarily. The better question is whether the infrastructure in place can support a modern pumping system, without compromising the reliability, accessibility to maintenance and capacity.
A well-engineered pump station retrofit can preserve important infrastructure and replace components that are no longer in compliance with functional requirements.
Begin with the structure that isn’t being replaced by anyone.
Wet wells can be the most expensive and difficult component to replace, as they are underground and connected to pipes that are already in place, and crucial to the process of removing wastewater.
Retaining the concrete structure could help in reducing excavation work and construction.
The deterioration of the area close to the access hatch could make this difficult. Romtec Utilities says that wet well hatches can be replaced in retrofits. It might be more reliable to replace the top layer instead of installing a brand new hatch on concrete that has deteriorated. This technique can be utilized to increase accessibility and the structure’s usability without needing to rebuild the whole wet well.
A new pump improves the engineering
Imagine a neighborhood which has experienced significant growth since the installation of its lift station. The existing pumps may no longer provide sufficient capacity to handle the increased flow of wastewater.
The upgrade of a pumping unit could include more horsepower, but this cannot be done without considering the entire system. Higher horsepower pumps might require modifications to discharge elbows, piping valves, electrical controllers, and other components.
Engineers must also consider the requirements of the hydraulic system, including the head of flow and total dynamic head. If you decide to install a larger pump and do not consider these aspects it could create operational issues rather than solve the problem. Making plans for future expansions during the initial design phase will enable you to build later on.
Make sure the wastewater is moving during Construction
A wastewater pump station retrofit introduces a challenge that ordinary equipment replacement projects may not face: the station may need to remain operational throughout construction.
The water continues to flow even when contractors are in the process of working. In the case of a project an interim bypass pumping system may be required to maintain service while existing equipment is removed and new equipment is installed.
Romtec Utilities addressed this type of challenge at the Federal Law Enforcement Training Center in Brunswick, Georgia.
The project included replacing two old wastewater lift stations in the process of maintaining operation at the facility. Site-specific engineering packages, bypass pumping techniques made it possible to meet existing station footprints as well as operational requirements. This illustrates how the order of construction should be carefully considered before installation.
If you think replacement is the better option, replace it.
Not every station can be repaired. A severely deteriorated wet well or a structural weakness or significant changes to hydraulic requirements may make an upgrade to a sewer lift station more suitable than altering the existing system.
The decision should account for structural condition, equipment compatibility construction access as well as service continuity and long-term operational requirements. Romtec Utilities starts retrofitting and replacing projects by identifying the components that will be retained and those that will need to be replaced.
The company then develops engineering solutions specifically for the site, preliminary plans and budget estimates. Prefabricated parts can also help with installation and can reduce building requirements that are required on-site.
The Project Isn’t Fully Complete Until the Pumps are Set to Start
The modern lift station must operate as a system. Before returning a lift-station to normal service, start-up tests, commissioning and equipment verification are necessary to verify that all pumps, control systems, and related equipment operate as designed.
Manuals for maintenance and operation along with instruction for operators are vital. Maintenance staff must understand the new equipment, operating procedures, and other documentation before they take over responsibility for the station.
A successful retrofit helps preserve the infrastructure and addresses the weaknesses that required modernization.
Municipalities and property owners have to be aware of the need for more than just immediate repairs. The most successful initiatives are those that incorporate new equipment into existing structures, and continue to provide essential services during construction. Also, they prepare the pumping system to continue running for a long time.