Lower Big Hayn e s C r e e k P u mp Stat i o n, G r av i t y Sewer, Force M ain an d S tor age Tan k
Just off the Centerville-Rosebud Road and beside Big Haynes Creek, the Lower Big Haynes below-grade pump station serves all of southern Gwinnett County. For equipment removal the team installed a bridge crane, left, to secure easy access. Also readily accessible is the bio-filter odor control system, right. In the distance, the four-million-gallon wastewater storage tank (125 feet in diameter x 44 feet tall).
24434.01 / 25445.00
Gwinnett County Department of Water Resources Lawrenceville, Georgia Engineering
Pump It Up
S H OW C ASE TWO
Lack of sewer infrastructure was a major obstacle for growth in southern Gwinnett County, Georgia. The county determined the Lower Big Haynes area was the perfect location to build a pumping station and force the main to push up to 25 million gallons per day of wastewater 34 miles uphill to a newly constructed reclamation center. Not only is the station the first of its kind in the county, but the team was challenged by the aggressive schedule, extreme site constraints, and concerned local residents. Now complete, Lower Big Haynes pumping station provides new options for wastewater flow, and is providing Gwinnett County previously unfulfilled sewer demands.
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ABOVE LEFT The most cost-effective method of getting the wastewater from the below-grade gravity collection system is the below-grade structures. ABOVE RIGHT Check and isolation valves being assembled. It was the most cost-effective, to assemble all the equipment before casting in the concrete walls. BELOW Construction of pump station substructure. Left to right, Pipe gallery, wet wells, and grinder chamber. The structure extends up 20 feet from this point to reach the surface level. Most of the dirt removed was good enough to use for backfill and was kept on the site.
TEAM
INTERVIEW /
PIC
Joe Reynolds
PM
Reg Harris, P.E. / Mike Orr, P.E. / Ken Richards, P.E.
PP
Jeff Behel
PC
DA L E MOS L EY, MIKE ORR
Describe the initial design of the pumping station in the beginning stages.
pump to the other end of the county, 34 miles away
The total project design included the trunk sewer improvements to route wastewater from the existing pump stations upstream that were to be abandoned to the Lower Big
Once you realized the complexity of the project, what tools did you use to organize all the teams and schedules? Mike: During the design of the project, we used Microsoft Project to schedule all design functions, and during construction we used Expedition. Expedition is a single-point source for sharing information between the contractor, owner, and engineer. It is used often on construction sites to keep track of equipment submittals, requests for information, construction schedules. It was also a way for us to keep in contact with the client and keep the client’s maintenance staff apprised of the construction progress. We used an online version of Expedition so the client could view all the info at the same time we were viewing it.
What was your biggest challenge on this project? Did you have full support from the county? DALE: The director of the Gwinnett County Water Resources Department wanted the facility complete and operational prior to January 2009, and everyone pushed to hit those dates. All departments of the county were behind the project from the start. We finished the design and construction six months ahead of schedule.
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Sounds like this grew into a pretty complex project. Can you describe the design and basic function?
Haynes Creek site and a portion of 34 miles of force main. The pump station includes wastewater grinders on the front end of the station for pump protection. Anything entering the collection system gets ground up before entering the pump station. We have three wet wells for the submersible pumps. The Brooks Road wet well contains three submersible pumps that pump up through three dry pit submersible pumps in order to boost the head enough to get it over the high point in the force main (Series Pumping). The No Business Creek wet well is designed for pumps to be added later to pump to the No Business Creek Water Reclamation Facility when flows exceed the capacity at the Hill Water Resource Center. The other wet well contains the storage tank pumps which are designed to pump directly to the four million gallon onsite wastewater storage tank.
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dale: Two of the county’s many wastewater treatment plants were investigated by the county for receiving additional wastewater flows. The Hill Water Resource Center was on the upper end of the county, and the No Business Creek Water Reclamation Facility was sort of situated in the middle of the county. The initial design was for a smaller pump station at the Lower Big Haynes Creek site to pump to the No Business Creek Water Reclamation Facility, but toward the end of the initial design, the county came back and said they’d decided they wanted to pump to the Hill Water Resource Center some 34 miles away. In order for us to pump this distance, we couldn’t use the same pump station layout, so we had to design one that utilized series pumping to make it that far. Series pumping is where one pump pumps into another pump that delivers the same flow rate but at a significantly higher discharge pressure. The Lower Big Haynes Creek Pump Station is kind of chained together with several other existing pump stations that are pumping in the same force main. We performed a hydraulic analysis of the force main, existing pump stations and new booster stations designed by others with our copy of ATF Fathom Hydraulic software for sizing of the pumps at Lower Big Haynes.
dale:
Dale Mosley
Hill Water Resources Center
The new Lower Big Haynes Creek pump station allowed for the decommissioning of the existing pump station and the Middle Big Haynes Creek and Brushy Fork Creek pump stations. The system will serve a 27,000 acre area and a current population of over 81,000 residents. Tennessee
Gwinnett County
Existing
No Business Creek Water Reclamation Facility
North Carolina georgia
GWINNETT COUNTY PUMPING STATIONS
New
south Carolina
Eliminated
alaba
34 Mile Route
Middle Big Haynes
ma
Brushy Fork Gwinnett County
Lower Big Haynes
Why did it need to be completed so quickly?
Were the cost savings due to the structural design alone?
This immediate area had no sewer service available, and growth was stopped by the Environmental Protection Agency (EPA). The county commissioners wanted to expedite the project because they were pushing for growth in the undeveloped section of the county and the local developers were pushing them.
dale: The cost savings were due to the energy that you would save for the years you would have otherwise had multiple pumps running and the replacement cost of the pumps and other equipment items in the smaller stations in the future.
DALE:
In terms of sustainability, how long will this pump station be viable?
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it’s all there, built and done; it looks really good
The life expectancy for a pumping station similar to this one is 50-plus years. The structural part of it will last 50-plus years and is designed to handle projected flow increases, but the equipment will not last that long, maybe 20 years max, which is pretty standard for the industry. The life of the pumping system is highly dependent on flow conditions, the wastewater characteristics, and performance of the regularly scheduled maintenance activities. dale:
MIKE: Also, it reduced the maintenance cost since the county was only pumping from and maintaining one station instead of several stations.
Because of the efficiency of this design, Gwinnett County was able to decommission one of its other stations. Explain how they were able to do that. DALE: There were a couple of existing smaller stations that were upstream of the new Lower Big Haynes Creek site, and they handled the small areas around those locations. We tied the flow from those stations into the new gravity service that feeds down to the new Lower Big Haynes Creek pump station. By not having to operate the additional stations, the county will see energy cost savings.
Did you involve the community in the initial discussions?
dale: Yes, we had community meetings and took renderings and drawings of preliminary layouts so that they could see what we were planning on doing at the site. They were very excited because of future development in the area. We never received any negative comments. The biggest comment was from a church that was concerned about when the generators would run. The generators are tested once a month, so we timed it so that they wouldn’t run during church services.
There was also a local resident llama farmer who said the construction noise and lights would adversely affect the reproduction of the llamas…we did our best to calm his fears. [laughter] mike: And also, the client chose to paint a mural on the tank as a way to soften the structure for residents in the area — not something you see very often. As you can see from some of the photos of the tank around the office, it is
The Lower Big Haynes Creek pump station also included the design of a four-million-gallon emergency wastewater storage tank and stand-by generators to provide reliable service and minimize potential for sewer overflows. Waste can be diverted into the storage tank, rather than bypassing a local creek, which is the water supply for Rockdale County. Out of aesthetic considerations for the community, a painting company was hired from Oregon to paint a mural on the entire tank. The 32,000-square-foot tank was completed in 5 days.
an impressive work of art. It was painted by hand with no templates by two brothers from a national company that just paints tanks. The two stood back from the tank and looked at what the trees looked like behind the tank and matched that. The paint used was the same type as normally used on that type of prestressed concrete tank and should last many years before needing repainting. Do you have any information on growth that’s happened as a result of the station?
How will this design serve as an example to other designers?
What aspect of this project are you most proud of? mike: Seeing it completed based on what we had to go through to get to that point. The piece of land that the county picked was surrounded by creeks on two sides (Big Haynes Creek and Brushy Creek), a cemetery, and a highway. All those creeks had buffer zones and ‘no-build’ areas associated with them. So by the time you added all those, you didn’t have a lot of land to work with. We had to build this massive structure with the large storage tank on it, and it was a pretty tight fit. Now that it’s all there, built and done, it looks really good.
Why was this particular layout so special?
We built quality into it and did it all in a timely manner to meet the county’s requirements. And we had a great team. You don’t see anything this size that pumps that far very often. It is a one-of-a-kind pump station project. ■
The layout is very straightforward and simple: easy access to the pumping system; ability to pull equipment, valves, piping, and pumps out for maintenance; how you get in and out of the station; access roads in and out; even the basic instrumentation and electrical controls. The overhead bridge crane and access doors over the equipment make equipment removal and replacement easy and safe — a piece of cake.
Dale Mosley has more than 30 years’ experience with treatment plant feasibility studies, large diameter water distribution system evaluation and design, storm water pump station design, water treatment process system design, and instrumentation and control systems design. As principal-in-charge for Lower Big Haynes, he was responsible for managing, planning, and design. Mike Orr, p.E., has more than 10 years’ of experience with water and wastewater design, utility relocations, permitting, transportation, and civil engineering. Mike served as project professional and civil engineer on the project.
dale:
dale:
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dale: It has more to do with the layout. We took a lot of time with the layout of the station, how it was actually set up to make maintenance easier. After looking at it, Gwinnet County said that they needed to do this for all their pump stations, and use it as a model layout for all their new stations.
It’s just what we do. We always try to take into account how maintenance personnel are going to get to the equipment, what kind of equipment they need to pull a pump or maintain a valve, and service the electrical system. Ken Koffman, part of our in-house electrical team, worked on this and as always did an excellent job of electrical layout. His expertise was invaluable. dale:
S H OW C ASE TWO
mike: Prior to the construction of the pump station, there was actually a moratorium on building permits in that part of the county because there was no sewer infrastructure for the area. So it wasn’t just that the area didn’t want to grow, they couldn’t grow. Unfortunately, the economy has limited what they hoped to have seen happen.
Did the extra design efforts take a special team or is it just part of what you normally do when designing a site?