All Under Control

Wholly owned watersheds around its key sources and diligent plant operations help Greenville Water deliver an exceptional-quality product.
All Under Control
Table Rock Reservoir

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For Greenville Water in South Carolina, effective water management includes applying protective controls to its watersheds, resulting in high-quality source and finished water, plus energy and cost savings.

In 1889, what was then the town of Greenville installed a pipeline to provide its 9,000 residents with clean drinking water. In the 1920s, city commissioners had the foresight to purchase a pristine watershed at the headwaters of the South Saluda River and Flat Rock Creek, which flow into what is now the Table Rock Reservoir.

The reservoir, in the foothills of the Blue Ridge Mountains, remains one of the few watersheds completely owned by a utility and maintained in its natural state. Nearly 100 years later, Greenville and its surrounding areas have grown to a population of more than 450,000. Table Rock Reservoir (500 acres) and North Saluda Reservoir (1,100 acres), both pristine supplies, are still the main sources of water.

Ensuring the future

Today, Greenville Water employs more than 230 people who help manage, maintain and oversee all aspects of the utility, including its two treatment plants. Water from Table Rock and North Saluda reservoirs is treated at the Stovall Plant, which went online in 2000. Duke Energy owns Greenville’s third water source, the 17,600-acre Lake Keowee, and that water is treated at the Adkins Plant, a conventional treatment facility completed in 1985.

The Greenville Water infrastructure connects the two treatment plants to deliver water to the city, retail customers in Greenville County and 14 wholesale customers. The system maintains 27 tanks and 19 pump stations and more than 2,600 miles of pipe.

“Our fundamental reason for being here is to ensure a sustainable future through supplying quality water to our customers,” says K.C. Price, director of water resources. He and his team continue to develop systems and processes to meet changing needs while improving sustainability practices.

Saving energy

Drawing water from mountain sources allows Greenville Water to focus on other sustainable activities, such as infrastructure replacement. At the Table Rock Reservoir, the utility replaced one 30-inch pipeline from the 1930s with a 42-inch pipeline. The larger pipe allowed for higher gravity flow (from 18 mgd to 21 mgd), reducing energy usage as pumps are not typically needed to meet demand.

In the treatment plants, the utility installed new chemical flowmeters and new feed pumps with lower horsepower ratings, allowing personnel to optimize chemical dosages to fit the flow. The improvements resulted in monthly energy savings of more than $1,000 and annual maintenance savings of $10,000. “We assessed our pumping schedule and were able to change operations to adjust to off-peak times for lower electrical rates,” says Rick Pfleiderer, assistant director of water resources.

Greenville Water also installed a dissolved air flotation (DAF) and filtering system (Leopold, a xylem brand) at the Stovall Plant to optimize turbidity. The process was chosen for its small footprint, treatment efficiency and low power consumption.

Keeping water pristine

The quality of the raw water is high, and the supply was unfiltered until construction of the Stovall Plant. After coagulation and flocculation, water flows to DAF tanks, where air diffusers on tank bottoms create fine bubbles that attach to floc, resulting in a floating, concentrated mass of floc. The floc blanket is removed from the surface, and clarified water is withdrawn from the bottom of the tank.

Greenville Water is looking at local opportunities to use the floc as a soil amendment or for some other purpose to save disposal costs. Utility leaders say substantial cost savings come from on-site management. “We staff a laboratory and maintenance crew who provide an efficient asset management program and on-the-spot notification of lab results,” says David Garland, Stovall plant superintendent. Employees monitor flow and actual feed rates in real time 24 hours a day and can optimize treatment accordingly.

Pristine sources and diligent operations allow Greenville to boast some of the best drinking water in the state. Water tests at 0.05 NTU 95 percent of the time, better than U.S. EPA and AWWA standards of 0.3 NTU and 0.1 NTU. The department has received the Partnership for Safe Water Presidents Award.

“Our employees are on board with the goals of Greenville Water,” says Garland. “They are responsible stewards and committed to ensuring that we provide the best water to our customers.”

Watershed conservation

One Greenville Water effectiveness measurement is comparison of current water-quality monitoring data with historic water-quality data. Records go back to the 1930s, and comparisons indicate virtually no change in water quality at Table Rock and North Saluda. This demonstrates the fruits of the utility’s source protection program.

Because it owns all the land within the two reservoirs’ watersheds, Greenville Water can control all activities near the lakes. In 1995, the Commissioners of Public Works signed a conservation easement with The Nature Conservancy, offering even greater protection for the watershed and water supply. The sustainability efforts have paid off.

“The watersheds are completely undeveloped and will remain as is,” says Pfleiderer. “We employ full-time staff to patrol the area and ensure that no activities are occurring that could adversely affect the public water supply.”

A main objective of the utility’s forward-looking water resources plan is to implement sustainable actions to maintain the water supply. The conservation plan continues to improve and evolve. So does the equipment in the treatment facilities. For example, this spring, Greenville Water will install six new air compressors in its DAF system to boost efficiency and save energy. Other programs being discussed include solar power, in-pipe power generators and alternative treatment chemicals.

Utility employees are also invested in high-quality water. They take part in training and professional development and often recommend ways to update infrastructure and improve distribution flow patterns. For instance, the engineering staff developed an optimized program for auto-flushing that reduces waste in the system.

“We have to be good stewards of the water supply,” says Price. “We have to be very forward thinking with our improvements because of changes in regulations, environmental management and total water management.” The legacy and foresight of the Greenville city commissioners from nearly a century ago continues to define the service approach at Greenville Water.


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