Wastewater Pumping Stations: Out of sight, but not out of mind

October 10, 2013

lda-logoBy Steve Bostic. P.E.

When was the last time you considered the wastewater infrastructure that operates behind the scenes in your city? Although these systems may operate well in the background, maintaining and updating the infrastructure is critical to preventing asset failure thereby better protecting public health and safety. It may be out of sight, but it shouldn’t be out of mind.

Most wastewater utilities own and operate pumping stations to “lift” sewage from one drainage basin to another for a final destination of a wastewater treatment facility. As long as a wastewater pumping station operates without experiencing equipment failures, overflows or other operational issues, updates to these stations may be delayed as municipalities or utilities companies deal with more pressing issues. However, that’s how wastewater infrastructure can become dangerously outdated. If necessary updates to these systems are deferred too long, it can lead to significant failures within the system resulting in undesirable consequences such as sanitary sewer overflows and damages to property or other infrastructure.

This past July, I presented a paper at the Kentucky-Tennessee Water Professionals Conference about monitoring these wastewater pumping stations. The presentation – entitled “Sanitary sewer lift station evaluation for smaller communities: Where is it? What is it? What condition is it in?” – was based on extensive studies conducted by LDA Engineering in two smaller communities with populations of approximately 30,000 that had been placed under Environmental Protection Agency (EPA) orders to address issues within their wastewater collection systems.

As a part of the EPA-mandated work, the approximately 30 wastewater pumping stations at each site were thoroughly evaluated and categorized to provide valuable information for planning, budgeting and operational purposes. Information collected ranged from general data, such as the station name, address and GPS location, and type (submersible, suction lift, self-priming, etc.), to detailed data, such as the brand and model and serial numbers of all the mechanical, electrical and instrumentation equipment.   Critical deficiencies were also noted and reported to our clients immediately.

The pumps were field-tested to determine their pumping rates, which were later compared to projected station flows to evaluate each station’s existing and future capacity. General site observations and numerous digital photographs were also provided to the client to assist utility personnel in developing plans for station improvements.

Using the data and site evaluations, we were able to develop a scientific approach toward creating a regular update and replacement schedule for the pumping stations. The LDA team created a pumping station rating system to “score” each station in terms of the urgency of necessary updates. Numerical values were assigned to various parameters and were totaled to provide the final rating for the station – the lower the score, the higher priority for station upgrades. This system was ultimately used to create a priority list of improvements and recommended schedule of pumping station upgrades.

At the end of our process, a comprehensive report was prepared for each client with detailed discussions of each pumping station, recommendations for improvements, preliminary cost estimates and a schedule for implementation.

Replacing this country’s aging infrastructure is one of the greatest challenges facing the hydraulic industry today. LDA Engineering helps its clients prioritize and develop a game plan to make sure its wastewater infrastructure, as well as its stormwater and drinking water systems, continue to function safely and efficiently. If a wastewater problem surfaces, it changes from oversight of upgrades to urgent repair mode and disruption of a vital public service.

Stay on top of the infrastructure. Even when you can’t see it.