A municipality has an aging wastewater lift station. Pumps are advancing towards the end of their useful lives, controls require modernization, and the access hatch needs to be replaced. Even though the concrete wetwell is structurally sound, it needs to be modernized.

Should the entire station be demolished and rebuilt? Not necessarily. One of the most important questions to ask is whether the current infrastructure will be able to support the pumping system of the latest standards, without compromising reliability and future capacity.

Image credit: romtecutilities.com

Retrofitting a pumping station can be an excellent way to preserve infrastructure and replace elements that are no longer functioning.

Begin with the Structures that nobody Wants To Replace

Wet wells can be the most costly and disruptive component to replace as they are constructed underground and attached to existing pipes, and crucial to the process of removing wastewater.

The retention of a concrete structure which is still functional could minimize the digging and construction.

However, the deterioration of the access hatch can complicate the choice. Romtec Utilities identifies wet well hatch replacement as a common retrofit requirement. Instead of gluing a hatch to deteriorated cement, replacing the whole top layer can be a more durable option. This will allow for greater access to the structure as well as prolong its utility, without having to replace the entire structure as well.

A More Powerful Pump Modifies the Engineering

Imagine a neighborhood that has seen a significant increase in population since the lift station’s initial installation. The pumps that are in place may not be able to handle the demand for increased wastewater flows.

Pumps with greater horsepower can be used to improve a pumping station, but the equipment has to be integrated within the system. Pumps with greater horsepower could require modifications to the discharge elbows and pipes along with electronic controls, valves and other parts.

Engineers must also consider the system’s hydraulic requirements, including the head of flow and total dynamic head. If you decide to install a larger pump without evaluating these conditions this could result in problems in operation instead of resolving the problem. Planning for future capacity when you are making the initial design process can help later expansions to be much easier.

Make sure that the wastewater is kept moving during Construction

Retrofitting a wastewater pump station presents a problem that normal replacement of equipment projects do not encounter: the facility may need to remain operational throughout construction.

Even when contractors are busy the wastewater still flows in. In the case of a project, temporary bypass pumping may be required to keep operation while the existing equipment is removed and new components are installed.

Romtec Utilities was able to address this kind of issue at the Federal Law Enforcement Training Center in Brunswick, Georgia.

The project consisted of replacing two older wastewater lift stations and ensuring the operation at the facility. The project was able accommodate the existing footprints of stations as well as operational requirements by using specific engineering for the site and packaged replacement systems. This example shows how important it is to look at the construction process before installing.

When replacement is the better option, replace it.

Not every station can be rehabilitated. A severely deteriorated wet well, inadequate structural capacity, or major changes in hydraulic requirements may make sewer lift station replacement more appropriate than modifying the existing installation.

The decision must take into consideration structural health, equipment compatibility construction access to the site, service continuity, and long-term operating requirements. Romtec Utilities begins retrofit and replacement projects by determining what components will remain and which require replacement.

From there, the firm designs site-specific engineering solutions as well as preliminary designs and budgetary estimates. Prefabricated components help simplify installation and decrease the time spent on construction.

The Project isn’t Over Until the Pumps Begin to Run

Modern lift stations should be operated as an integrated system. Prior to returning a lift station to normal service, start-up testing, commissioning, as well as verification of equipment are required to make sure that all pumps, controls and other equipment are operating as designed.

The manuals as well as the training of operators are equally essential. Prior to taking over the responsibility of the maintenance of a station, employees must be aware of the latest equipment, procedures and also the documents.

Retrofitting infrastructure is a great way to preserve its value, while also solving the shortcomings that led to modernization.

For municipal facilities and facility owners This means looking beyond immediate repairs. The strongest project is one that integrates the new equipment with existing structures, keeps up with essential services during construction, and then prepares the pumping system to last for years of continued operation.