Charlotte County Utilities
Wastewater Division - East Port Water Reclamation Facility
HISTORY
In 1982, when the East Port Bio-Nitrogen Plant was built, it was a modern
facility that offered secondary treatment of wastewater for the residents
of Port Charlotte. Over the years since the original plant went
online, much higher standards were developed for the treatment of domestic
waste. In 1994, the Florida Department of Environmental Protection
(FDEP) issued a Consent Order to Charlotte County giving strict deadlines
to improve the wastewater treatment system. These ordered improvements
included the introduction of reclaimed water to the Port Charlotte area.
This would allow the County to start reusing water for irrigation, rather
than injecting much of the treated wastewater down the deep well.
CONSERVATION AREA
The East Port site encompasses nearly 700 acres of land, much of it dedicated
to wildlife, woodlands, and conservation. The water reclamation facility
itself is two injection wells and two storage reservoirs cover approximately
80 acres.
The newly expanded spray irrigation fields encompass nearly 325 acres.
Fifty-one acres have been set aside as an official conservation easement,
and the remaining land is mainly woodlands. The site is home to
more than 20 varieties of birds, including great egrets, osprey, and Carolina
wrens. Many other wildlife make East Port their home as well.
Gopher tortoises, scrub jays, bobcats, armadillos, cottontails, and alligators
are among the inhabitants.
THE WASTEWATER TREATMENT
PROCESS
Wastewater (influent) enters the East Port Water Reclamation Facility
(WRF) through a 36-inch force main. It passes through a magnetic
flow meter, where the rate of wastewater flow is measured and recorded.
The influent then flows through an automatic bar screen that removes rags
and plastics. Grit and sand settle out as the influent flow continues
through the vortex grit chambers.
The next stage of the treatment process occurs at the anoxic/aeration
basins. This two-stage process removes the biochemical oxygen demand
(BOD) and nutrients from the wastewater. In the first stage, the
anoxic basin removes the majority of the BOD and part of the nutrients
from the influent. In the second stage, the aeration basin removes
the remaining BOD and nutrients. These aeration basins are living
biological environments and they require the same things to live that
we do: food; oxygen; and nutrients. Mechanical aerators provide
oxygen, and the influent provides food and nutrients for the microorganisms.
The mechanical aerators have two speeds, which allow plant operators to
run the aerators at low speed whenever possible, thus reducing operating
costs. A stable environment must be maintained by the operators
to ensure the health of the microorganisms.
After the biological treatment in the aeration basins is complete, the
biosolids (microorganisms) flow to the secondary clarifiers. Here,
the biosolids are allowed to settle to the bottom, and the clarified water
(effluent) flows over the top. Some of the biosolids are returned
to the anoxic basins to mix with the influent, and some of the biosolids
are removed (wasted) from the clarifiers to the digester.
The clarified effluent is then treated either to a standard for public
use as reclaimed water, or a standard for restricted access reuse on the
County's spray irrigation fields. For public use reclaimed water,
the effluent is sent though gravity sand filters. This effluent
is filtered by layers of sand and anthracite to remove the remaining suspended
material. The effluent from the gravity sand filters then flow into
chlorine contact basin No. 1. The combination of sand filtration
and chlorine addition provides high level disinfection, which is required
for all reclaimed water distributed to the public. The reclaimed
water is used to provide water for irrigating area golf courses and a
mobile home community. The reclaimed water system also provides
water for the pumps, chlorination points, and general clean-up at the
facility.
For restricted access reuse, any excess effluent from the clarifiers bypasses
the sand filters and goes directly into chlorine contact basin No. 2.
Effluent from the basin is pumped into one of the two effluent storage
reservoirs. Effluent from the reservoirs can be sprayed onto the
irrigation fields or pumped down one of the two deep injection wells.
BIOSOLIDS
Operators use the term "biosolids" for the solids removed from
wastewater during the treatment process. Biosolids from the secondary
clarifiers are pumped into rotary drum thickeners and discharged into
the aerobic digester. They remain in the digester until they break
down and stabilize, thus reducing the volume of the biosolids. This
reduction helps to save costs by reducing the size of aerobic digesters
needed, and cutting down on the number of trips required to transport
residuals to a land application site. Biosolid residuals are transported
in a sludge tanker truck to an approved land application site, where they
are applied to the land for beneficial reuse.
CONTINUOUS MONITORING
The East Port WRF has the benefit of a state-certified Environmental Laboratory
onsite to assist staff in monitoring the condition of the facility.
The East Port Laboratory monitors pH, dissolved oxygen, BOD, solids, nutrients,
and fecal coliform at various stages of the treatment process. Biosolids
are monitored for specific oxygen uptake and pathogen reduction to verify
the stability of the biosolids product prior to land application.
Laboratory results provide the basis for process control. This data
enables operators to make operational adjustments as needed to meet stringent
standards. Accurate analysis assures the regulatory agencies that
essential parameters such as BOD and solids removal are successfully accomplished,
while daily testing confirms that each stage of the treatment process
is operating properly and efficiently. Charlotte County's East Port
WRF meets and even exceeds treatment standards established by the Florida
Department of Environmental Protection (FDEP) and the United States Environmental
Protection Agency.
