Lift Station Engineering for Super-High Head Sewer

Romtec Utilities engineers pump stations for many different applications. Frequently in new construction applications, the site of the pump station includes design challenges as construction is pushed into more difficult locations. A typical challenge is overcoming geographical elevations to reach an existing gravity sewer system. This is the basic premise of almost every lift station, but in certain locations, the elevation changes are so dramatic that the lift station must handle very high head conditions. Romtec Utilities handles high head pumping conditions in all types of applications, and in some scenarios installing multiple lift stations is the best solution for overcoming geographical barriers.

The first thing to understand about using multiple lift stations is the design requirements. In new construction, such as with a housing development, the initial expected sewage flows will be typically low to medium. When selecting pumps, there are limited pump options for pumps that handle low flows at super high head. The best selection in these conditions are positive displacement pumps, which are specialists in this type of pumping. Many municipalities, however, have no experience with positive displacement pumps and also have design standards that specify a particular brand or style of pump. It is always a good practice for municipalities to maintain design standards to increase the effectiveness of their maintenance operations, and the overwhelming majority of municipal standards favor specifying submersible centrifugal pumps.

A different engineering solution is necessary to utilize submersible centrifugal pumps in a low flow super-high head pumping scenario. A great solution is what is casually referred to as a “daisy chain.” This is essentially a sewer system that uses lift stations as “steps” to overcome a geographical barrier. Each lift station pumps to the next lift station at a higher elevation until the sewage can be discharged to a gravity line. This configuration lessens the head requirements for each segment of force main, which opens up the availability of suitable pump selections. In this way, municipalities can maintain their desired lift station design standards while providing a sewer tie-in for valuable new construction areas.

The best value of this configuration is that it is a reliable engineering solution that allows a municipality to maintain its standards. Design standards are created and maintained to simplify the maintenance operations for a municipal district. In this scenario, using multiple lift stations may appear to be a complex solution with added costs, but it is actually a simple solution. Engineering a new lift station that contrasts from a set standard is easy enough, but owning a lift station that is unlike all the other systems requires additional training and new vendor contacts. Additionally, municipalities typically have discounts from vendors where they order frequent parts or services that would not be available in a new system design. Using multiple systems in a standard configuration means that owning and operating the new systems is business as usual.

Romtec Utilities sees a lot of projects that deal with extreme engineering challenges. One aspect of these projects is the understanding of the equipment, but just as important, another aspect is understanding the needs of the customer. The best lift station solution strikes a balance between meeting requirements dictated by mathematics and physics and meeting requirements dictated by human organizations with preferences, experiences, and relationships. These two components go hand-in-hand on virtually every project, and in a super-high head situation, it is more important than ever to design the best lift station. Romtec Utilities only works on pump and lift stations, and we excel at getting our customers the best systems to meet their unique needs.