The Problem
Baldwin County, located approximately
70 miles south of Atlanta, GA, has a land area of approximately
164,800 acres, and supports roughly 7,500 water customers with supply
from the City of Milledgeville. Although smaller in landmass than
Putnam County, Baldwin County has a much larger population with a
strong industrial and commercial base. Historically, the population
centers have been the City of Milledgeville and Lake Sinclair (north
and east Baldwin County). In the last 10 years, development has been
extensive throughout south and west Baldwin County.
Putnam County is a relatively large
county with a vast majority of the population congregated in three
areas of the County - Lake Oconee, Lake Sinclair and the City of
Eatonton. Currently there are over 4000 residences in the Lake
Sinclair Area within Putnam County. Most of the commercial and
industrial activity within Putnam County is restricted to the area in
and around the City of Eatonton and the two major transportation
corridors of US 441 and GA Hwy 44.
Since neither Baldwin nor Putnam
counties have a water treatment facility, the citizens in these area
are currently serviced primarily by individually owned residential
wells; however, the projected growth trends in the multi-county region
surrounding Lake Sinclair are putting a strain on the existing water
utilities.
In April 2001, the State of Georgia
enacted legislation to create the Sinclair Water Authority (SWA). The
purpose of the SWA is to provide safe drinking water on a regional
basis to both Baldwin and Putnam Counties. It was decided that a
regional surface water treatment facility was in the best interest of
both counties. Lake Sinclair, which is geographically the dividing
line between Northern Baldwin County and Southern Putnam County, will
be the source of water for the new treatment facility providing
adequate potable water for the citizens of the region.
The SWA was particularly concerned with
the microbial contamination possibilities in the area. All of the
wastewater from Putnam County, which is know as the "Dairy Capital of
the Georgia", drains into Lake Sinclair. Since dairy cattle waste was
the source of the 1993 Cryptosporidiosis outbreak in Milwaukee,
conventional technology was viewed as an inadequate application. Also,
from the perspective of microbial protection, Lake Sinclair has a
tremendous number of older dwelling units with aging septic tanks
around the lake.
The SWA hired Carter & Sloope to select
a new water treatment technology. They recognized membrane
filtration as the technology which could provide the best possible
protection against microbial contamination, and therefore, the safest
possible drinking water for the region’s residents.
The Solution
A pilot study was conducted to select
the best membrane system that could produce treated water meeting or
exceeding state and federal drinking water guidelines with the minimal
operator attention.
Several membrane manufacturers systems
were piloted, and the ZENON Membrane Solutions (part of GE Water &
Process
Technologies) Z-BOX packaged water treatment plant was selected.
Selection was based on pilot study results which showed excellent
treated water quality in terms of pathogen and virus removal,
turbidity, manganese and iron removal, TOC removal and THM and HAA
formation potential. In addition, the system was able to run
with less than two hours of operator attention per day.
Process Overview
The SWA had decided on a multiple
barrier approach for both microbial and chemical contaminant concerns.
The primary barrier for microbial concerns is the membrane filtration
process.
The Lake Sinclair Z-BOX packaged plant
incorporates ZeeWeed 1000 ultrafiltration membranes. With a nominal
pore size of 0.02 micron, ZeeWeed 1000 membranes act as a physical
barrier to virtually all suspended particles, and can consistently
provide 4-log removal (99.99%) of Giardia, Cryptosporidium, bacteria
and viruses. These removal rates ensure that the water from the
treatment plant will meet state and federal drinking water guidelines,
and protect residents from microbial contamination.
The initial capacity of the water treatment plant is
to produce 4 million gallons (15, 142 m3) over 16 hours, in one day.
The build-out capacity is to produce 6 million gallons (22,712 m3)
over 18 hours, in one day. The ultimate capacity of the water
treatment plant is to produce 8 million gallons (30,283 m3) over 21
hours, in one day.
The
proposed raw water intake will draw water from the Oconee River area
of Lake Sinclair. There will be chlorine dioxide injection at the raw
water pump station to provide the first barrier against waterborne
pathogens. On a seasonal basis, potassium permanganate will also be
dosed at the raw water pump station to oxidize iron and manganese. The
raw water will then flow through a conventional
coagulation/flocculation process, which will help flocculate organic
particles. Alum will be used as the coagulant and powered activated
carbon (PAC) may be used seasonally to help in the removal of smaller
organic material not easily removed by conventional coagulation
process.
After membrane filtration, the treated
water will be treated with MIOX (Mixed Oxidant) as a second source of
disinfection, lime for the adjustment of pH, a polyphosphate for
corrosion control, and fluoride for health benefits. Process waste
from all processes at the water treatment plant will be direct to one
of two alum lagoons. The settled water from the lagoons will be
discharged back to Lake Sinclair.
Upon completion, the Lake Sinclair Drinking Water
Treatment system will be the first packaged ZeeWeed 1000 plant in the
state of Georgia.

