Hit a switch, lights come on. Place dampened hands under a dryer, and it automatically blows warm air. Flip a lever on a toilet tank, and swoosh, it’s gone. Sometimes, even that’s automated.
A lot of amenities – services – we take for granted.
But the infrastructure that’s behind all this – the electricity, water and sewage – mostly, goes unnoticed.
Three weeks ago, the city of St. Robert brought online Pump Station No. 6, a state-of-the-art $2.4 million sewage lift station and sewage lines in the wooded areas of northeastern part of town that carries nearly 50 percent of the city’s sanitary sewer system.
For John and Jane Q. Public, it’s no big deal. Just another completed public works project. For them, they’re OK with it, as long as it doesn’t raise their rates and the lift station performs adequately enough to keep the stuff they flushed from backing up in the floor drains in the basement of their home.
Pump station No. 6 goes a long way toward that end.
“This is a state-of-the-art system,” said Lyle Thomas, St. Robert Public Works Director. “People expect that when they flush their toilet they expect it to go somewhere.”
The system is shiny new, and it’s more efficient, its two pumps capable of handling 4,400 gallons of waste per minute.
It features three 180-horsepower pumps, two of which are used daily – and the second only during peak periods. The third pump is exclusively a backup, which is used should one of the other two fail.
And, there are added benefits to the newly designed system.
“This system is also so much greener than what we had before,” said Jeff Meadows, principal of C.M. Archer Group, P.C., the contractual engineer for the city.
“We have reduced the city’s six lift stations to just two. We’re using fewer lift stations and that’s better for the people of St. Robert.”
Meadows explained during the 1980s, the common thinking was to move toward “innovative-designed systems” and that often meant moving sewage from lift station to lift station, creating a network of pumping stations.
Meadows explained that’s passé now as eliminating the number of pump stations reduces the chance of equipment and pump failure and reducing the use of electricity.
“Back then, there wasn’t as much of a concern about the use of electricity. Nowadays, we have to think that way, think greener. This system lifts to a point and then were using more gravity lines to move the sewage,” Meadows said.
The new system uses 13,000 linear feet of 16-inch sewer main with about 25 percent of it gravity-based.
“The upside of this is the greater portion of your line you have gravity-based, the less maintenance you’ll have,” Meadows said.
However, there is a downside. Sewage that travels great distances via a gravitational network tends to lose its oxygen, which makes is much more pungent and actually slows the treatment process.
The challenge then became how to oxygenate the sewage in a linear system that has a greater percentage of its line served by gravity.
The options seemed clear. What the city saved on eliminating pump stations it seemed it was now going to have to spend on chemical treatments – of $30- to $40,000 annually – and the hardware to apply the chemicals at another $100,000 annually.
That’s when Public Works Foreman Steve Long recalled seeing a device at a conference that simply added oxygen to the sewage the old fashioned way – letting it fall.
“I saw this system in a magazine that I picked up at a conference,” Long said. “I went back and found the device, a Vortex.”
The device is cylindrical with a spiraling funnel and baffles down the shaft that force oxygen into the sewage tumbles through it.
Explaining the process, Meadows and Long said it is not unlike pouring water from pitcher to pitcher to add oxygen.
“It’s gravity-driven, an agitation process,” Long said.
The Vortex system cost $25,750 total, construction and installed. The alternative would have cost the city $140,000 the first year and an estimated $35,000 annually.
“It’s new green technology,” Meadows said. “It’s the first one in the state of Missouri. None other like it.”
That’s not the only amazing facet of No. 6.
At the wooded location there is a fenced control building with panels, circuit boards and monitoring stations that look more like the control deck of a nuclear submarine than a sewage treatment monitoring station.
The system also features a Caterpillar diesel 300 KVA backup generator that is operated at 10 a.m. every Wednesday, just to make sure it’s operational.
“It’s natural gas-powered,” said Thomas, the city engineer. “This way when the power goes out we don’t have to worry (about pumping diesel fuel).”
“It’s really pretty amazing,” Meadows said. “We did this without raising (sewer) rates. The public doesn’t even know,” he said of the project that was funded through the Missouri Public Utilities Alliance, a financing group that aids cities with large-ticket improvements.
“I never dreamt all of this was necessary before I came to work for the city. It’s amazing,” said Thomas, the Public Works Director.
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