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Project Details

Location: City of Danville, Kentucky

Project Description: The City of Danville's existing Water Treatment Plant (WTP), the Coldiron-Watkins Memorial WTP, was constructed in 1924 with subsequent expansions or renovations in 1952, 1957, 1966, 1983, and 1990. No major improvements have been made since 1990, and the WTP's condition is beginning to deteriorate. The WTP has a capacity of 10 million gallons per day (MGD). The average daily treated water in 2010 was approximately 5.6 MGD, with a maximum day of 7.2 MGD (72% of rated capacity).

The City's raw water source is Herrington Lake (Dix River), a plentiful water source that presents water quality challenges. The City's raw water pump station conveys water from the Lake to the WTP via 18-inch and 24-inch transmission mains.

Danville Plant

Water Systems Map

Project Drivers

1. Growth of Water Supply Needs/Regional Impact
The City of Danville is a regional supplier of potable water. The City's distribution system serves all or parts of the communities of Perryville, Junction City, and Hedgeville. In addition, the City is a wholesale supplier to several surrounding utilities, as shown below:

Surrounding Utilities
Utility
Customers Served
Affected Population
Danville System
10,300
25,750
Garrard County Water Association (Wholesale)
5,352
13,000
Lake Village Water Association (Wholesale)
2,219
5,500
Hustonville Water District (Wholesale)
1,875
4,600
Parksville Water District (Wholesale)
1,594
3,900
North Mercer Water District (Wholesale)
4,308
10,000
Stanford (Emergency Connection)
2,926
7,300
Total
28,574
70,050


In addition to the existing retail, wholesale, and emergency connections, the City is well-positioned to become a future wholesale supplier to the following additional water utilities:

Additional Water Utilities
Utility
Customers Served
Affected Population
City of Lancaster
1,793
4,400
McKinney Water District
1,852
4,600
Northpoint Training Center
-
654 (prison population)


The cumulative demand of these systems exceeds 1.5 MGD. Expansion of the WTP will increase the City's economic viability as a regional supplier. WTP expansion will also assist regional planners and the industrial authority in attracting industry and jobs to the Danville/Boyle County region.

The WTP expansion will provide sufficient capacity to meet the water demand for the next 40 years. Water demand projections are summarized in Figure 1.

Figure 1 Water Demand Projections
Water Demand Projections Graphic

2. Regulatory Requirements
The City of Danville is faced with the need for WTP improvements to meet the EPA's new Stage 2 Disinfectants/Disinfection By-Products (D/DBP) Rule. Disinfection by-products (DBPs) are created when raw water high in organic content is disinfected. DBPs include trihalomethanes (THMs) and haloacetic acids (HAA). Distribution system sampling results (shown in Figure 2) indicate ongoing difficulty meeting the HAA regulatory levels. In fact, Danville has been in violation of HAA requirements in three of the last eight quarters. Without enhancements to the conventional WTP treatment process, Danville will likely remain in violation and fail to meet the Stage 2 regulations to be implemented in 2014.

Figure 2 THM HAA Compliance Data
THM HAA Compliance Data Graphic

3. Facility Upgrades to Modernize WTP
Many of the WTP structures and facilities were constructed prior to 1970, and are in need of refurbishing and/or modernization. Typical service life of major WTP equipment is approximately 40 years and over 75% of the equipment at Danville's plant exceeds this benchmark.

Proposed Improvements
Project Component
Project Drivers Addressed
Green/Energy Saving Features
Expand WTP from 10 MGD to 12 MGD (with footprint for future 15 MGD expansion)
1
-
Construct advanced treatment processes using Granular Activated Carbon (GAC) contactors, or equivalent
1, 2, 3
X
Modernize WTP pumps, valves and related equipment
1, 3
X
Replace tube settlers and other process units
1, 2, 3
X
Upgrade SCADA and instrumentation systems
2, 3
X
Upgrade electrical system and install standby generator(s)
1, 3
X
Solids processing improvements
2, 3
X
Improve reliability of raw water intake/pump station
1, 3
-
Construct second line from pumps to raw water mains
1, 3
X
Electrical and related improvements
1, 3
X
Replace Perryville standpipe with elevated tank
1
-