Water Treatment

Central Arkansas Water has two water treatment plants, the Ozark Point Treatment Plant and the Jack H. Wilson Treatment Plant. The two plants have a current combined seasonal treatment capacity of 157 million gallons per day (MGD). Water consumption during the summer of 2000 peaked at just over 121 MGD, which has been the highest in the history of the water utility.

The Jack H. Wilson Treatment Plant is located in the Pleasant Valley area of Little Rock. The first phase of the Wilson Plant, originally dedicated as the Pleasant Valley Water Treatment Plant, was completed in 1966 with a capacity of 25 MGD. A second-phase expansion in 1977 increased the plant’s capacity to 50 MGD. Further expansions increased the plant’s treatment capacity to 100 MGD in 1984. Process optimization improvements lead to a seasonal increase in treatment capacity to 133 MGD in 2008.

In 1993, a 9,000 square foot expansion of the Wilson Plant was completed. The two-level addition included a pilot plant, expanded laboratory space, and expanded administrative offices. To enhance our efforts to comply with increased monitoring and testing requirements of the federal Safe Drinking Water Act, the expanded water treatment complex features separate organic, inorganic, microbiological, and wet chemistry laboratories as well as work stations for the laboratory technicians.

Subsequent modernization, optimization and rehabilitation of the plant were undertaken in two phases, with the latest having been completed in 2002. Phase I for the Wilson Plant began in September 1999, and included the construction of a 5 million gallon underground concrete contact chamber, designed to optimize the chlorination process. Also, baffling was added to existing clearwells.  Phase II began in March 2000. The improvements at the Wilson Plant consisted of the rebuilding of 16 filters and the addition of a state-of-the-art air scour backwash system. Also included was the redesign of the flocculation and sedimentation basins. Finally, the Wilson Plant also went through various electrical, instrumentation, and control system upgrades to further improve the treatment process. The Phase I and Phase II improvements led to a seasonal increase in treatment capacity at the Jack H. Wilson Plant to 133 MGD in 2008.

In August, 2000, Central Arkansas Water began a comprehensive upgrade to our Supervisory Control and Data Acquisition (SCADA) System. Our Intellution computer software allows us to control operations and processes at the treatment plants and at the 23 remote storage tanks and 22 booster pumping stations on the distribution system. The added features of the computerized system also provide us with better compliance reporting capabilities. The computer software assists us in the control and collection of data on the various parameters required for monitoring under state and federal regulations and prepares the data in compliance format.

In 2007, construction and installation was completed on a new High Service Pump Station and a new switchgear/generator project at the Wilson Plant. The new pump station, at a cost of $5.1 million, added two 14-MGD, 500 HP pumps and has room for two future pumps. The new pump station was constructed in conjunction with the North Belt Transmission Main Project and will supply additional water north of the river and to master metered customers to the north including Jacksonville, Cabot, and North Pulaski Water. It will also pump 25 percent of its capacity to west Little Rock in the intermediate pressure zone. The new $3.7 million switchgear/generator project added two new standby diesel generators, replaced two utility service transformers, and installed a new electrical switchgear building. The two standby generators with, 1600 kw capacity, will each provide the plant with sufficient power to continue treating and pumping water to the central Arkansas area during a power outage.

The Ozark Point Treatment Plant is located in the Heights-Hillcrest development district of Little Rock. Some of the basins at the plant were originally constructed in 1886, but have undergone major renovation and modification.

The first phase of the present chemical and filter building at the Ozark Point Plant was completed in 1938, followed by expansions in 1948, 1954, and 1957. Subsequent modernization and rehabilitation of the plant were undertaken in two phases, with the latest having been completed in 2002. The plant has a rated capacity of 24 MGD.

The most recent comprehensive expansion/modifications program (for both plants) represents a $31 million investment for the utility between 1999 and 2003. Phase I at Ozark, which began in September 1999, consisted of a new 12 MGD pump station and rehabilitation of two finished water storage clearwells. The new pump station replaced an aging facility.

Phase II work began in March 2000, and included the rebuilding and conversion of eight filters. The addition of a state-of-the-art air scour backwash system for the newly converted filter process and major repairs to the clearwells were made. Finally, various upgrades to electrical, instrumentation, and control systems were completed.

The Ozark Point Plant’s raw water source is primarily from Lake Winona, supplemented by Lake Maumelle by way of Jackson Reservoir.