A municipality is home to an aging wastewater lift station. The pumps are at the limit of their lifespan and the controls are inefficient as well as the access hatch is damaged. Even though the concrete wetwell is structurally sound, it’s time to be upgraded.

Image credit: romtecutilities.com

Do you think the station should be completely gone? Not necessarily. One of the most important questions to consider is whether or not the existing infrastructure will support pumps that meet modern standards without compromising reliability and future capacity.

Retrofitting an pumping station that has been carefully designed can save valuable infrastructure, while also replacing parts that are no longer in compliance with the operational standards.

Start with the structure that nobody would like to replace.

It’s expensive and difficult to change the wet well because it is in the ground, linked to pipes, and is necessary to collect wastewater.

Retaining the concrete structure may make it easier to dig and build.

The deterioration of the area close to the access hatch could affect this decision. Romtec Utilities identifies wet well hatch replacement as a standard retrofit requirement. Instead of gluing a hatch to deteriorated cement, replacing the whole top layer can be a more reliable option. This could improve access to the structure as well as prolong its utility, without having to rebuild the entire wet well.

The engineering of the pump with more power is distinct

Imagine a neighborhood that has grown significantly from the time of the first lift station installation. It is possible that the current pumps aren’t sufficient to handle the increasing flows of wastewater.

Pumps that have higher horsepower can be used to improve pumps, but the equipment needs to fit within the system. To make the pumps more powerful there is a possibility that you will need change the discharge elbows or piping. You may also need to change electrical controls and valves.

Engineers should also consider the hydraulic requirements of the system. This is a consideration for flow as well as total dynamic pressure. The installation of a bigger pump prior to assessing the requirements may cause more issues than it resolves. The planning for future expansions at the time of your initial design process will make it much easier to grow later.

Keep waste water 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 to work, and wastewater continues to come in. According to the study, a temporary bypass pumping system could be required to ensure service is maintained as existing equipment is removed or new components are added.

Romtec Utilities took on this task at the Federal Law Enforcement Training Center, Brunswick, Georgia.

The project required the replacement of two aging wastewater lifting stations while maintaining the operation at the facility. The project was able to adapt to existing station footprints as well as operational requirements by using specific engineering for the site and modular replacement systems. This example shows the importance of focusing on construction sequencing before the construction process starts.

If you think replacement is the better option

It is not possible for every station to be restored. A badly degraded wet-well insufficient structural capacity or significant changes to hydraulic requirements might make a sewer lift station replacement more appropriate than modifying the existing system.

The decision should account for the condition of the structure, compatibility with equipment access to construction, service continuity, as well as long-term requirements for operation. Romtec Utilities begins retrofit and replacement projects by identifying which components will be left and which need to be replaced.

From there, the business develops site-specific engineering solutions including preliminary designs, as well as budgetary estimates. Prefabricated components can also help facilitate installation and cut down on construction-related requirements on site.

The project won’t be finished until the pumps kick in

Modern lift stations should be operated as an integrated system. Prior to returning a lift station to normal service, start-up testing, commissioning, and equipment verification are necessary to ensure that all pumps, control systems, and equipment work in accordance with their design.

Operator training, as well as maintenance and operation manuals are equally important. Maintenance personnel should be familiar with the latest equipment as well as operational procedures, as well as the necessary documentation prior to taking responsibility for the station.

A successful retrofit will preserve the infrastructure, while addressing the weaknesses that required modernization.

This means that municipalities and owners of facilities must consider more than just immediate repairs. The most successful project is one that integrates new equipment with existing structures, maintains essential service during construction, and prepares the pumping system for years of continual operation.