Hemphill Water Treatment Plant
Drinking Water Service Area
About Hemphill Water Treatment Plant The Hemphill Water Treatment Plant (WTP) has a permitted capacity of 136.5 million gallons of water per day (MGD), which supplies drinking water to approximately 65 percent of Atlanta’s service area, including portions of William Hemphill Fulton County south of the Chattahoochee River and Atlanta’s wholesale water customers. The treatment plant, named after Mayor William Hemphill who purchased the 200-acre plant site in 1893, employs conventional treatment that consists of rapid mixing, hydraulic flocculation, sedimentation, dual media filtration, disinfection, finished water chemical application, and finished water storage. Finished (treated) water is stored in two clearwells at the WTP until pumped into the distribution system; solids are processed at the Hemphill settled solids facility.
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The City of Atlanta has 12 finished water storage tanks with a total storage capacity of 37 MGD.
75
Sandy Springs
285
285
85
ATLANTA
Decatur
20
Chattahoochee River
river intake, a 30-inch-diameter pipeline located on the east bank of the Chattahoochee River just north of Peachtree Creek, and treated the river water at the new Hemphill WTP. The Hemphill WTP has undergone multiple upgrades and expansions over the last 100+ years. As Atlanta’s need for clean water grew between 1893 and 1920, a second (36-inch) raw water supply main was constructed along with a second raw water storage reservoir, creating a combined reservoir capacity of approximately 500 million gallons of water. Additional sedimentation basins and pressure filters were also installed that increased the capacity of the WTP to 41 MGD. In 1923, capacity was increased again, and process improvements were made with the installation of seven concrete rapid sand filters that raised capacity to 62 MGD. Additional upgrades included a new chemical application building, a gravity chemical mixer, a 10 million-gallon concrete clearwell tank for storing treated water, and a third (48-inch) raw water supply line from the Chattahoochee steam powered pumping station. New boilers and pumping units were also installed at the pumping station.
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Fulton County
East Point
285
College Park
Hemphill WTP
Union City
Chattahoochee Hills
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Palmetto
Fairburn 85
● Water Treatment Plants ■ Retail ■ Wholesale Finished Water Storage Tanks
The Hemphill WTP hosts two reservoirs that are designed to receive water from the Chattahoochee Raw Water Pump Station via four raw water mains consisting of 30-inch, 36-inch, and 48-inch cast iron pipes and a 72-inch steel pipeline. The reservoirs (#1 and #2) are interconnected, and each can supply water to the Hemphill WTP by gravity flow. Should the reservoirs encounter low water conditions below the gravity flow levels, emergency pumps allow water to be drawn directly from Reservoir #2 and pumped into the WTP’s central mix basin. Atlanta’s first water system was built in 1851 and consisted of five artesian (aquifer-drilled) wells. In 1891, the City’s Water Commission recommended withdrawing up to 10 MGD from the Chattahoochee River to address water shortages. Three years later, the City constructed its first pumping station and
In 1938, two additional sedimentation basins were constructed, and three years later the Hemphill WTP went through a third major expansion that brought the plant’s capacity to 72 MGD with seven new gravity filters. The two reservoirs were expanded in 1987 to approximately 550 MGD, and a 72-inch supply line was also added in 1994. The Hemphill WTP was recognized in 2013 as a top performer in the Better Buildings Challenge (BBC) for its 48-percent reduction in energy usage since 2009. Improvement measures at the plant included decommissioning the original pump station built in 1876 and building a new station with energy efficient equipment and lighting. Hemphill was also recognized by the BBC in 2017 with the MVP Award, and in 2019 with the Municipal Leadership MVP Award.
Hemphill Water Treatment Plant Filtration Process COLLECTION
COAGULATION & SEDIMENTATION
Aluminum Sulfate (alum) Sodium Hypochlorite (chlorine)
Water is drawn from the Chattahoochee River to the treatment plant.
Chemicals are added to form sticky particles in the water. These particles sink to the bottom, and the water moves on.
Chattahoochee River Raw Water Intake 280 Million Gallons Raw Water Pump Stations (x5)
Reservoir #2
Central/Flash Mix Basin
Flocculation Basins (x2)
Clarifier
Settling Basin
Phosphate Sodium Hypochlorite Fluoride Lime
Sedimentation Basins (x6)
Clearwell No. 2: 15 Million Gallons Clearwell No. 3: 10 Million Gallons
Coal Sand Gravel
Finished Water Storage Tanks (x12)
Finished Water Pump Station (x8)
Underground Clearwells (x2)
Post Flash Mix/ Disinfection
Filtration Basins (x17)
DISTRIBUTION
DISINFECTION
FILTRATION
Clean, safe water travels through miles of pipes and comes out of your faucet.
Sodium Hypochlorite (chlorine) is added to inactive waterborne bacteria or microorganisms that are found in untreated water.
The water passes through layers of charcoal, sand, and gravel to remove smaller particles.
Hemphill Water Treatment Plant – Treatment Process The Hemphill Water Treatment Plant (WTP), located on 17th Street in northwest Atlanta, GA, supplies drinking water to approximately 65 percent of Atlanta’s service area. The treated drinking water originates from raw water from the Chattahoochee River. The City of Atlanta is permitted to withdraw a maximum of 180 million gallons per day (MGD) using a raw water intake located approximately 250 yards upstream from the Peachtree Creek and Chattahoochee River junction. Water from the raw water intake goes into a pump station located just downstream; five pumps send water from the pumping station to the Hemphill Reservoir #2. The reservoir has a storage volume of approximately 280 MGD, which is conveyed to the Hemphill WTP. The Hemphill WTP has a permitted peak day treatment capacity of 136.5 MGD. Raw water from the Hemphill Reservoir #2 flows into the treatment plant where chemicals are added to help remove contaminants and particles from the water, and to promote coagulation and flocculation. Chemicals added in the central mix/flash mix basin include aluminum sulfate (alum) to help separate particles out of the water, and sodium hypochlorite (chlorine) for initial disinfection. Coagulation and flocculation cause the solid particles in the water to clump together, allowing the particles to settle easier in later treatment plant processes. After the chemicals are added, the water is separated into two flocculation basins where a serpentine flow configuration allows time for the particles to clump, or floc, together (see plant flow diagram on previous page). Next in the treatment process is particle settling in sedimentation basins. Each sedimentation basin (six total) consists of a clarifier and a settling basin. The clarifier is a large round basin with long rotating arms. The rotating arms slowly move the flocs (or clumps) to the center of the clarifier where they settle to the floor of the basin. The flocs are removed through a 16-inch pipe and sent to another facility for further treatment. After clarification, the water moves into the settling basins where the remaining, lighter flocs settle to the bottom of the basin. The settled flocs are called sludge, and the sludge in the settling basins is removed through drainage valves and a sludge pump. After sedimentation, the water enters the filtration basins (17 total), which contain gravity filters that consist of anthracite (coal) and sand layered over gravel.
The filtration basins capture suspended fine particles that may have slipped through the previous stages of treatment. Treated water leaves the filtration system through underdrains located beneath the basins. The water then flows through two vaults to undergo the post flash mix process. This involves further treatment using chemicals, including sodium hypochlorite (chlorine) for disinfection, increasing the pH using lime, promoting dental hygiene using fluoride, and protecting the distribution system from corrosion using phosphate. After the additional chemicals are added, the treated water is sent to two underground storage tanks called clearwells. The treated water is then pumped by the finished water pump station (eight pumps) to 12 finished water storage tanks in the City of Atlanta’s water distribution system.
Fun Facts
Awards
Atlanta has approximately miles of drinking water pipes
2,790
358
Crews responded to water main breaks in FY 2019
Georgia Association of Water Professionals (GAWP) • 2019 Water Gold Award • 2019 Certificate of Achievement for Surface Water Treatment 100 MGD and Over • 2017-2019 Certificate of Distinguished Merit for Water Safety • 2016 District 3 Water Top Operator Award • 2011-2016 Water Platinum Award • 2007-2010 Water Gold Award
Hemphill WTP supplies water to the Hartsfield-Jackson International Airport, Mercedes Benz Stadium, Atlanta City Hall and Georgia Environmental Protection Division (EPD) Headquarters The City currently has a raw
The Future of Raw Water Storage: Bellwood Quarry
180
water permit of MGD from the Georgia Department of Natural Resources, EPD
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Over people toured the Hemphill WTP in 2019. Hemphill WTP hosts an annual Trick or Treatment Halloween Tour.
Better Buildings Challenge (BBC) • 2019 Municipal Leadership MVP Award • 2017 MVP Award • 2013 - 2017 Top Performer Energy Efficiency
Innovations • Solar panels will be placed at the Hemphill WTP to support energy conservation • Atlanta's Upper Westside Waterworks Greenspace projects continue to add public greenspace near the Hemphill WTP • System Control and Data Acquisition (SCADA) system upgrades are ongoing to increase the number of processes that can be automated at the Hemphill WTP In 2020, the City of Atlanta completed construction of a new Raw Water Storage Reservoir located at the Bellwood Quarry. It adds approximately 2.5 billion gallons of raw water storage for the Hemphill WTP. This is almost nine times more raw water storage than was available and supplies the City of Atlanta with 30-90 days of water service if water could not be pumped from the Chattahoochee River.
Tours One-hour guided, walking tours are offered at the Hemphill WTP that provide guests a behind-the-scenes look at the water treatment process, the plant’s unique story, and how water travels through the facility and is delivered to your home. Contact our office to schedule a tour today!
Time Slots Tuesday and Thursday 10:00 a.m. – 11:00 a.m. or 1:00 p.m. – 2:00 p.m. Please email us at dwmcommunications@atlantaga.gov. Include the following information in your email: Name of school/program/organization, contact person name and phone number, tour date, tour time, name of plant to be toured.
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Thinking about becoming a water treatment plant operator? The State of Georgia requires the following for an operator to become certified: • Take and pass an exam that demonstrates that the applicant has the necessary skills, knowledge, ability and judgment as appropriate for the classification
DEPARTMENT OF WATERSHED MANAGEMENT ADMINISTRATIVE OFFICES
• Have a high school diploma or a general equivalency diploma (GED)
72 Marietta Street, NW Atlanta, GA 30303 Mon-Fri – 8:15 am to 5:00 pm atlantawatershed.org
• Have the defined minimum amount of on-the-job experience for each appropriate level of classification.