Due to continued rapid growth, Gwinnett County, Georgia, is projected to experience peak day
demands in excess of their permitted 150-million gallons per day (mgd) treatment capacity over
the next several years. Although the county has begun construction of a plant which will provide
an additional 75-mgd of treatment capacity, it will not be completed until early 2004. This paper describes how the county, while facing the
possibility of being unable to meet peak water demands, developed a strategy for
using finished water storage for multi-day averaging of peak demands.
Since a large number of Gwinnett County residents commute out of the county to work, peak
demands are typically seen during the weekends, and have historically been as high as 1.68 times
the average annual day demand. An analysis was completed to determine the frequency and
distribution of peak days to decide if using dedicated storage for multi-day averaging of the peak
demands was a feasible alternative. The total storage needed to equalize demand for anticipated
periods where demand exceeded available 150-mgd plant production was calculated. The analysis
showed that a volume of 40 million gallons (MG) of projected multi-day averaging storage
(MDAS) would allow the county to meet anticipated peak demand periods until 2004.
Two fast-track projects were undertaken in order to provide this reserve MDAS storage. The first
was the construction of two 10-MG ground storage tanks and a booster station. A second project
involved the construction of a new 20-MG clearwell and a transfer pump station at the existing
water treatment plant.
These two projects effectively increased the county's ability to meet an additional demand
equivalent to 18-mgd above their current production through multi-day averaging of demands
during peak demand periods. Using MDAS was found to be an economical option, with the
combined cost for these two projects at approximately $18 million. The additional effective
water production capacity is provided at a cost of approximately $1.00 per gallon of equivalent
treatment capacity, which compares favorably to construction of additional water treatment
production capacity.
Most importantly, since these smaller projects could be designed, permitted, and constructed
much more rapidly than constructing additional treatment capacity, the county was able to
implement them much faster and continue to supply the rapidly growing county population. Includes 2 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 450 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 06/16/2002 |
