How a Detailed Retrofit Scope Helps Contractors Avoid Confusion

An aging wastewater liftstation is located in a municipal. The pumps are at the final stage of their life The controls are old and the access hatch is worn out. The concrete wet well is structurally sound.

Image credit: romtecutilities.com

Do you think the station should be destroyed and rebuilt? Not necessarily. The more useful question is whether the existing infrastructure can accommodate a new pumping system with no compromise in availability, reliability or capacity in the future.

Retrofitting an existing pump station can be a fantastic method to save infrastructure and replace parts which are no longer in use.

Begin with the structure that nobody would like to replace.

Wet wells can be the most expensive and difficult element to replace because they are buried and connected to existing pipes and are essential for wastewater collection.

If the concrete structure remains in good condition, retaining it could decrease excavation and construction work.

The loss of space surrounding the access hatch may cause problems with this decision. Romtec Utilities has identified wet-well hatch replacement as an important retrofit. Instead of attaching a hatch to cement that has deteriorated replacing the entire top layer could be a more durable option. This technique can be utilized to increase accessibility and the structural’s functionality without having to rebuild the entire wet well.

A Powerful Pump Changes the Engineering

Consider a neighborhood that has experienced a significant increase since the opening of a lift station. Existing pumps may not be able to cope with the increased flow of wastewater.

A pumping station upgrade could include higher horsepower pumps, however equipment selection isn’t a part of the surrounding system. Higher horsepower pumps might require adjustments to discharge elbows, pipes valves, electrical control and other parts.

Engineers must also think about the hydraulic requirements of the system. This is a consideration for flow as well as total dynamic pressure. Installing a larger pump without considering the circumstances could create more problems than it resolves. The ability to plan future capacity prior to initial design makes later expansion considerably easier.

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.

Contractors continue working and the wastewater will continue to flow. According to the report, a temporary bypass pumping system is necessary to maintain service as the existing equipment is taken down or new components are added.

Romtec Utilities tackled this type of challenge at the Federal Law Enforcement Training Center in Brunswick, Georgia.

The project required the replacement of two old wastewater lift stations and ensuring the operations of the facility. Site-specific engineering, packaged systems and bypass pumping techniques allowed for the existing station footprints as well as operational needs. This case illustrates the importance of taking time to consider the construction sequence before constructing.

In the event that replacing becomes the best option

Not all stations are suitable for rehabilitation. A seriously damaged wet well, inadequate structural capacity, or significant changes in the hydraulic requirements can make sewer lift station replacement better than making changes to the existing structure.

The decision must take into consideration structural condition, equipment compatibility accessibility to construction to the site, service continuity, as well as long-term requirements for operation. Romtec Utilities begins retrofits and replacements by identifying parts to be left in place and those which need replacement.

The business will then design custom-designed engineering plans as well as budget estimates and initial designs. Prefabricated parts are also helpful in arranging installation and decreasing the number of on-site requirements.

The project won’t be finished until the pumps start

The modern lift station must operate as a system. Before returning the lift station back to service, testing its startup and commissioning tests will ensure that the pumps and control equipment and other components work in accordance with established specifications.

Training for operators and maintenance and operation manuals are equally crucial. Prior to taking over the responsibility of the maintenance of a station, employees should be familiar with new equipment, procedures and the documentation.

Retrofitting infrastructure successfully preserves its value, while eliminating the limitations that prompted modernization.

This means that municipalities as well as facility owners must think beyond immediate repairs. The most successful projects combine new equipment with existing structures. They will maintain the important services during construction and then prepare the pumping systems for a lifetime of operation.