Newsletter and Technical Publications
<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>
4.11 Case studies (Topic k)
||Orange County Eastern Water Reclamation Facility
|| Design - Average 72 ML/d; Peak Hour - 144 ML/d.
||Tim Madhanagopal, P.E., DEE, Plant Manager - (407) 249-6248
The Orange County Eastern Water Reclamation Facility is located in one of the
most rapidly growing areas in the United States. This advanced water reclamation
system was designed to enhance the environment of the Econlockhathee River basin
in east Central Florida, reduce demand on potable groundwater by providing
sufficient reclaimed water for non-potable uses, and provide sufficient
wastewater treatment capacity for the East Orange County in Florida and
constructed in phases since 1984. This facility allowed the decommissioning of
six secondary treatment plants that had directly discharged effluent into
surface water. The plant has a permitted capacity of 72 ML/d, and currently 43
ML/d of municipal wastewater. The plant was recognized for its outstanding
performance by many regulatory agencies and professional organizations.
Raw wastewater is first screened, then enters a pista grit- grit removal
system. Following grit removal is a five-stage Bardenpho nutrient removal system
consisting of an in-line fermentation tank, followed by the first anoxic tank,
an aeration basin, the second anoxic tank, reaeration and secondary
clarification. Final ABW filters polish the effluent, which is chlorinated.
Dechlorination occurs in the dechlorination zone of the wetlands, prior to
reclaimed water entering wetlands vegetation zone. The treatment facility is
linked with an integrated reuse system consisting of aquifer recharge,
industrial reuse and wetlands enhancement. Air from the headwork's is treated
for odor control in three biofilters.
Reclaimed Water Quality
The following table compares the permitted annual average values for the
reclaimed water and the actual measured values for 1998:
||Actual (1998) Values
The plant consistently produces reclaimed water considerably better than
required by stringent regulatory permit. The reclaimed water quality is analyzed
daily using 24-hour flow proportional composite sampling.
Reclaimed water is 100% reused, thus reducing the demand on precious
groundwater in the Florida aquifer. The reuse system supplies cooling water for
the Orlando Utilities commission's Stanton Energy Center, a 900-megawatt power
plant located adjacent to the facility. The facility now supplies this power
plant with 90% of reclaimed water produced at the facility. The reuse of
reclaimed water for cooling purposes was one of the first approved programs in
The water reclamation facility also reuses reclaimed water in a combination
of natural and created wetlands. This was one of the first such systems
permitted by the Florida Department of Environmental Protection (FDEP) under
exemptions to the wetland rules. The County in cooperation with the University
of Florida- Center for Wetlands conducted extensive research on the effect of
reclaimed water in wetlands. This research has produced very valuable
information on the use of reclaimed water in the wetlands. These wetland's
provide nutrient reduction and additional cleansing of the reclaimed water.
Currently, less than 10% of the reclaimed water is reused in the wetlands. In
turn, the natural wetlands are enhanced to provide a valuable habitat for
diverse plant and animal species.
The wetlands are sized for 23.5 ML/d. There are 60.7 ha of natural wetlands
and 60.7 ha of former pine flatwoods that have been converted to wetlands. A
distribution system with seven application zones delivers reclaimed water to the
wetlands uniformly. A channel collects and carries the water from the natural
wetlands to the created wetlands. There is an additional 66.8 ha of off-site
wetlands through which effluent flows before reaching a small creek that is
connected to the Econlockhatchee River. This river was designated as Outstanding
Florida Water by the State of Florida, partially due to benefits created by the
water reclamation project.
There is also a 9.5 ML/d rapid infiltration basins for aquifer recharge.
In addition to the above, nearby golf courses are permitted to irrigate with
the reclaimed water. Provisions for expansion include additional golf courses
and green space irrigation.
Waste sludge discharged from the clarifiers is dewatered in belt filter
presses to 14 to 15% solids and hauled to a nearby landfill where the sludge is
landfilled with the municipal solid waste.
The wastewater customers pay a monthly fee to cover the operations cost. All
developers pay an impact fee to cover the plant capacity required for their
development, which finances plant expansions.
Operations, Maintenance and Management
The plant employs 30 people with annual operating costs of $5.2 million U.S.
The County helps pay for certification classes, certification renewals, commercial
driver's licenses, work related training and professional registration. As a
result, 19 of the plant's employees are certified by the State of Florida. The
County also reimburses the employees up to $1,000 per year who continue their
education at local colleges and universities. Many of the staff are long term
employees, with an average of 12 to 15 years' experience at this plant.
Management places a high priority on planning ahead through yearly capital
improvement program based on operational and upcoming regulatory requirements.
The facility uses computers for data management, record-keeping, maintenance
and personnel scheduling, purchase orders and interactive safety training. A
Computer Maintenance Management System (CMMS) and a Supervisory Control and Data
Acquisition (SCADA) system are being implemented in accordance with the
Automation Master Plan to improve the County-wide wastewater service efficiency.