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PLANT BACKGROUND: 1930’S – Original plant construction. Plant provided
primary treatment with Imhoff Tank. 1956 – Plant expanded to one (1) MGD and
upgraded to include secondary treatment. Expansion included the
following:
1. two (2) primary clarifiers
2. one (1) decant tank
3. one (1) final clarifier
4. one (1) set of step aerators
-Imhoff tank converted to sludge digester
- sludge drying beds upgraded
1966 – Plant became hydraulically and organically overloaded. 1986 – Plant expanded to present status of two (2) MGD tertiary
treatment. The Somerset Borough Wastewater Treatment Plant is a 2.0 million
gallon per day advanced wastewater treatment plant. The wastewater
is brought to the treatment facility through over twenty-eight miles
of underground sewer lines and five (5) pumping stations. As the
raw wastewater enters the facility, it first passes through the preliminary
treatment process where rags, grit, and other debris are removed
or shredded for further treatment. The wastewater now flows into
the main wetwell where it is then pumped up to the beginning of the
primary treatment stage. In primary treatment, the wastewater flows
are measured and split up into four (4) rectangular twelve (12) feet
deep primary clarifiers where the velocity of the wastewater is slowed
to allow the settleable matter to precipitate to the bottom of the
clarifiers. This settled matter (sludge) is removed from the clarifiers
and placed in a separate treatment process. Greases and other floating
debris are also removed in the primary clarifiers. After the wastewater passes through the primary clarifiers it is
ready to go on to secondary treatment. This stage is a biological
form of treatment and is the heart of the treatment process that
is split into two (2) steps. In the first step, the wastewater splits
and flows into two (2) roughing trickling filters that are seventy-five
(75) feet in diameter and four (4) feet deep. These filters are filled
with a synthetic honeycombed media. The media provides an area for
bacteria to grow. These bacteria feed on the organic matter in the
wastewater, thus eating the pollutants out of the wastewater. The
wastewater flow is distributed over the media through rotary distributor
arms. Some of the flow that passes through these filters is recycled
for a better degree of treatment. The remainder of the flow goes on to the second step in the secondary
treatment process. In the second step of this process the wastewater
is pumped up to the bio-towers. These bio-towers are similar to the
roughing trickling filters in that they also are packed with a synthetic
media that the wastewater flows through. The differences between
the bio-towers and the roughing filters is that the bio-towers are
thirty (30) feet tall and forty-five (45) feet in diameter and the
bacteria growing in the bio-towers is different from those in the
roughing trickling filters to remove a different type of pollutant
and the synthetic media is slightly different also. A portion of
the flow off of the bio-towers is recycled for a greater degree of
treatment. After the flow passes through the two (2) steps of biological treatment,
it splits up into three final clarifiers where the velocity of the
wastewater is again slowed to allow the remaining solid matter in
the wastewater to settle out. After the flow passes through the final
clarifiers it is ready to go on to the final stage of treatment known
as disinfection. The flow now splits up into two (2) contact chambers
where chlorine is added to kill off the harmful bacteria that may
be present in the wastewater. After the wastewater goes through this
stage of treatment, it is discharged into the east branch of Coxes
Creek. The wastewater discharged must meet strict federal and state
guidelines. This is achieved only through carefully monitoring the
various treatment processes and making process control changes accordingly.
At present, the treatment plant treats about 1.5 million gallons
of wastewater per day. During periods of heavy flows, the treatment
plant can handle up to 5.0 million gallons per day and divert another
2.2 million gallons into the storm overflow lagoon, making the total
peak capacity for a twenty-four (24) hour period about 7.2 million
gallons. Any wastewater that is diverted into the lagoon is pumped
back to the head of the treatment process for complete treatment
when the heavy flows subside. As for the solids (sludge) that are removed from the clarifiers
in the various stages of treatment, they are placed in their own
specialized biological treatment process knows as two (2) stage anaerobic
digestion. This process takes upwards of twenty-eight (28) days to
complete. In this process, the sludges are broken down and stabilized.
A by-product of this treatment process is methane gas that is captured
and used for heating the sludges and buildings. After the sludge
passes through the anaerobic digestion process it is run through
a device called a belt filter press. The belt press removes the water
from the sludge and the dewatered sludge is then placed in a dumpster.
The dumpster once filled, is hauled to a specially permitted landfill
where the sludges are disposed of. At present, Somerset Borough hauls
about fourteen (14) tons of sludge per week to the landfill. The Somerset Borough wastewater treatment plant is staffed seven
days a week by state licensed operators who are responsible for all
aspects of operation and maintenance of the complex wastewater treatment
facility. We hope these few brief paragraphs have been informative
to you. Should you be interested in a group tour of our treatment
facility, please contact the Water and Sewer Department at 814-443-2661.
We appreciate your time in looking over the materials we have provided
to you. It is imperative that we protect our environment from pollution
as water is certainly a vital component in the future of mankind.
Again, thank you for your time and interest.
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