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Stormwater Pump Station for the Sacramento Municipal Utility District

Romtec Utilities recently completed a large project for the Sacramento Municipal Utility District (SMUD) at the new East Campus Operations Center that is currently under construction. The Romtec Utilities supply included a wastewater lift station and a large stormwater pumping station. These two packaged pump stations are a part of construction that began on this facility in September of 2011. Each package pump station offers tremendous benefits for the East Campus facility, which is a champion of green building design and energy efficiency.

At the heart of this project is green building design, environmental impact, and energy efficiency. These were the key areas of focus when SMUD decided to add a new 51-acre office and utility complex. The design included a six-story corporate office building, several low-rise structures for various uses, a large equipment and storage yard, and a large solar array incorporated into the parking. In order to make all of this construction possible, the site needed to have reliable and effective stormwater and wastewater pump stations.

When designing facilities for Leadership in Energy and Environmental Design (LEED) certification, a major consideration is planning for stormwater events. A facility like the East Campus Operations Center includes impervious surfaces like the parking lot, the building roofs, the vehicle maintenance and fueling sites, and more. These surfaces do not allow stormwater to be absorbed naturally by the soil. Additionally, as stormwater flows across the impervious surfaces, it collects contaminants and minerals that can be harmful to the ecosystems of natural waterways, i.e. streams, ponds, or rivers.

Large stormwater events can create hazardous environmental conditions as contaminants rush into unprepared ecosystems. Collecting stormwater and treating it to remove contaminates is one solution to negate the impact of impervious surfaces with regards to stormwater. Including a system to accomplish this is important for an environmentally friendly and certified facility. Romtec Utilities designed, supplied, and started-up a large stormwater pump station to exceed the stormwater expectations of the East Campus facility. But at this facility, there were more than just environmental considerations for designing a stormwater pump station of this size.

The East Campus facility is located on a plot that is essentially a giant depression. The land was purchased from a past gravel quarry which had scraped down the top soil during years of business. The result was a manmade lakebed waiting for rain. SMUD was building in a large critical path for flooding, and the options were to either raise the elevation for 59-acres or to prevent critical amounts of water from collecting. The Romtec Utilities supplied pump station would accomplish the latter.

The stormwater pump station was a no-fail proposition, not only for the benefit of the environment but for the protection of the facility as well. Romtec Utilities engineered this pump station in a triplex configuration to ensure its continual operation. That means that this station included three pumps in the wet well. With a triplex configuration, the pumps will cycle between one or two pumps operating at a time with the third pump standing-by in case a pump fails. The lift station controls will cycle starts between the three pumps to maintain equal operation times. This prolongs the lifespan of the pumps while decreasing wear and maintenance requirements.

A unique feature of this stormwater lift station was the variable frequency drives (VFDs) for the pumps. Pump stations are essentially collection basins with pipes that bring water in and pipes that take water out, and each has its limitations. For this system, there was a maximum of 8500 gallons per minute that could be handled by the downstream system, i.e. treatment, force main, etc. The VFDs limited the output of the pumps so that when two were working in tandem they did not exceed pumping 8,500 gallons per minute, which was the limit of the system. The station was engineered this way so that one pump could meet the needs of typical stormwater events when operating at full power but so that two working together would not overstress the system.

Another aspect to designing a facility this large is managing the outflows that over 750 SMUD employees generate. The location of the East Campus facility required a sewage lift station to pump wastewater from the facility to gravity lines to the municipal treatment. Romtec Utilities designed a duplex lift station with two, 15HP Ebara submersible sewage pumps. This wastewater lift station included simple alternator lift station controls with Anderson floats for level sensing. The wet well is over 25 ft deep with a separate dry pit valve vault.

SMUD was able to get an economical lift station with a number of failsafe components to protect the environmental certification for the facility. Together, the two Romtec Utilities supplied pump stations accomplished the goals of SMUD by providing durable, dependable, cost-effective, and environmentally friendly water infrastructure for the East Campus Operations Center.

The Romtec Utilities portion of the $111 million-dollar project was one of the initial construction phases at the East Campus. The total project should be completed by fall of 2013. This project is great example of a governmental agency constructing modern and environmentally conscientious facilities while managing costs responsibly.

For more information on SMUD, click here.

For more information on the East Campus Facility, click here.

To see Romtec Utilities’ stormwater pump stations, click here.

To see Romtec Utilities’ wastewater lift stations, click here.

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