The West Central Conservancy District (WCCD), located in Hendricks County, Ind., was established in 1992 and comprises fve
geographical areas. The district was formed to resolve
sewer issues that the service area was experiencing with
the local utilities company in the mid-1980s. The utilities
company was no longer able to meet the requirements
for its wastewater treatment operations set by the Indiana Department of Environmental Management.
In 1990, local developers formed a committee and
decided to run sewer lines from their residential developments to the utilities plant at their own expense in
order to ensure success of their properties. The developers purchased the utilities company to ultimately form
the new district treatment facility in 1992.
The district started out with
less than 100 customers but experienced rapid growth in the
area, resulting in several plant
upgrades. In 1995 the plant
expanded from 500,000 gallons per day (GPD) to 900,000
GPD and by 1999 served approximately 2,000 customers.
To keep pace with the area’s
growth, WCCD expanded
again in 1999 to a 2. 4 million-gallon-per-day (MGD) plant
and again in 2005 with an increased capacity of 5.0
MGD. By 2011, the district was serving a customer base
of 8,000. In addition to residential customers, it also has
119 commercial users and one industrial user.
The 2005 expansion included the installation of a
four-basin AquaSBR® system, which has the capability to treat a much larger capacity in a small footprint
on the available land space. WCCD chose the AquaSBR
system not only for its treatment capacity in a small
footprint but also for its outstanding performance.
The plant’s only challenges have been with infuent
grease from several area restaurants and high-strength
waste from a large bakery. To resolve the issue, WCCD
increased inspection of the restaurants’ grease traps
and drains, and enforced pretreatment ordinances. The
plant also closely monitors the biomass rate, keeping it
signifcantly low to produce the highest quality effuent
during higher loadings from the restaurants.
AQUASBR SYSTEM PROCESS
The AquaSBR system operates on a simple concept
of introducing a quantity of waste to a reactor, treating
the waste in an adequate time period, and subsequently
discharging a volume of effuent plus waste sludge that
is equal to the original volume of waste introduced to
the reactor. This “Fill and Draw” principle of operation
involves fve basic steps: Fill, React, Settle, Decant, and
Sludge Waste. The system may be designed to include
seven individual phases of operation but the inclusion or
duration of any individual phase is based upon specifc
waste characteristics and effuent objectives.
Where nutrient removal is required, a simple adjustment to the SBR’s operating strategies permits nitrifcation,
denitrifcation, and biological phosphorus removal. Optimum performance is attained when two or more reactors
are utilized in a predetermined sequence of operation.
Flow from WCCD’s screening process is split into
two separate biological treatment trains. The four-basin
AquaSBR system functions as the “West Train” with
a capacity of 3. 5 MGD. Effuent from the SBR is sent
through a separate ultraviolet (UV) light disinfection
system, then recombines with the “East Train” effuent. Due to the high dissolved oxygen permit of 5 mg/L
(winter) and 6 mg/L (summer), the combined fow is
then directed to re-aeration prior to fnal discharge into
White Lick Creek.
Aqua-Aerobic Systems provides on-site operator training as part of its Customer Service offerings.
WCCD requests the training annually to keep its operations staff current on new or cost-effective ways to
optimize treatment and troubleshoot any issues. WW
For more information about Aqua-Aerobic’s AquaSBR system, visit
Treatment Capacity in a
Presented by Aqua-Aerobic Systems
Overview of two of the basins in the four-basin AquaSBR system.
Mixer combined with fine-bubble aeration is operating in one of the plant’s