Designing for the Worst Hour, Not the Average Day: Pump Station Capacity Planning

Pumping projects may seem easy on paper. Water enters at one location and must be pumped to another. In actuality the distance between those two points could be a matter of fluctuating rate of flow, elevation differences in solids, pressure demands storage capacity, controls and electrical equipment, maintenance access and restrictions at the site.

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Romtec Utilities starts the design of an pumping station by delineating the operational conditions, rather than selecting the equipment from an inventory. Initial designs and budgetary details will be developed in accordance with what the project will actually require.

Consider: Where are we going?

The technology changes instantly.

Domestic sewage may contain solids, and can experience a variety of variations in the daily flow. The wastewater lift station will be required when gravity conveyance cannot or does not work. Engineers need to take into account the following: expected inflow the condition of the pump, its peak, capability, wet well behavior discharge requirements, and how the equipment is operated and maintained.

Different challenges are presented by industrial water. The water used in a manufacturing or processing facility could need to be caustic, oily, or heated with high temperatures or pressure. Romtec Utilities designs systems for industrial applications that range from food processing to power generation to databases, pharmaceutical waste facilities and oil and gasoline facilities.

Rainfall can create a completely new operating system

Stormwater systems are often inactive for prolonged periods and then suddenly be required to manage large amounts in the event of a major storm.

A stormwater lift station associated with a detention basin, for example, must work with the site’s larger drainage strategy. The water that flows through the detention basin. The temporary storage handles the immediate volume, and the pumping system transports the collected water to an authorized discharge point.

Romtec Utilities supplied this type of service for a commercial park development in Norco, California. The development needed the construction of a pumping station that would empty an existing detention system into the public stormwater drainage system. This station had to be engineered as part of the development’s drainage infrastructure rather than treated as an isolated piece of equipment.

“Package Doesn’t Denote “Off the shelf”

A common misconception is that a system of pumping packages is just a predetermined assortment of components.

For engineered infrastructure, packaging could also mean coordinating the key components into one project-specific system. Meters, pumps, valves as well as controls, communications structural elements, and more equipment can be selected around the required duty conditions.

This strategy is especially useful when the new system needs to be connected with an existing infrastructure. Municipal and industrial plants facilities usually do not provide a lot of area or pristine installation conditions. It could be necessary to adjust equipment around existing structures, piping, electrical systems and schedules.

Capacity Planning Can Have Real Consequences

The cost of undersizing is higher when the facility grows.

Romtec Utilities, a Portland International Airport utility company, has designed and constructed an sewer interceptor lift station for the PDX Next project. The new station had to be designed to accommodate twice the capacity at peak flow since the airport had expanded.

This case illustrates a fundamental engineering concept: Design conditions are not limited by the limitations of what a building can handle on a typical afternoon. Engineers should be aware of what happens at peak demand.

The job isn’t done until the Equipment Arrives

In the end, drawings and calculations will eventually become a functioning system. Installation coordination and documentation are essential to the success of the long term.

A properly engineered pumping system is ultimately determined by what happens in the years following the construction. The decisions made during the initial design are evident when the pump needs to be maintained as flows rise or when the weather strikes.

For Romtec Utilities, integrating those choices into a comprehensive project-specific pumping system helps transform parts of equipment into infrastructure specifically designed for the conditions it will actually face.