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Case
Study 10-St. Augustine Wastewater Treatment Plant # I
St. Augustine, Florida
Wastewater Treatment |
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Background Data: |
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Case Study: Wastewater Treatment |
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Location: St. Augustine Wastewater Treatment Plant # I St.
Augustine, Florida |
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The St. Augustine Wastewater Treatment Plant # 1, with a design
flow of 5 MGD, treats an average of 2.3 MGD of both industrial and
domestic wastewater. Infiltration is a major concern to City
personnel. Flow amounts increase by over 100% during rainy
periods. |
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This aerobic wastewater treatment facility has been generating an
average of 40 tons per week of low grade sludge. The abnormally
high quantity and low quality of sludge generated can be
attributed to the facility's groundwater infiltration problem.
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Sludge disposal costs for the St. Augustine Wastewater Treatment
Plant # 1 were above $100,000.00 per year. This figure does not
take man hours, sludge press maintenance, or polymer usage into
account. According to David Parker, Wastewater Superintendent, the
true sludge disposal costs could be over $250,000.00 per year. |
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Scope: |
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It was determined that the use of PX-700TM could reduce the
quantity of sludge generated at the St. Augustine Wastewater
Treatment Plant # 1, thus reducing overall sludge disposal costs.
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PX- 700TM, a microbial bio-catalyst, was to be used as an additive
at the St. Augustine facility . |
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The anticipated result from the use of PX-700TM was to be an
overall reduction of sludge generated by the St. Augustine
Wastewater Treatment Plant # 1, thereby reducing costs associated
with sludge disposal. |
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Facility personnel were to gather pertinent data to analytically
determine the effectiveness of PX- 700TM. Records were maintained
for Mixed Liquor Suspended Solids (MLSS), Mixed Liquor Volatile
Suspended Solids (MLVSS), Waste Activated Sludge (WAS), Fecal
Coliform, Tons of Sludge Generated, Man Hours to Press and Dispose
of Sludge, Amount ofPolymer Used, Sludge Transport and Disposal
Charges. |
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Treatment Procedures: |
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On June 8, 1998, PX- 700TM was introduced into the aerobic
digester at the St. Augustine Wastewater Treatment Plant # 1.
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Since the only objective was to eliminate the amount of sludge
generated, and thereby reduce the cost associated with sludge
disposal, the digester was chosen as the injection point
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56.1 ounces were injected on a flow proportional bases into the
digester during each 24 hour period, this converts into 0.19 mg/l.
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At the time of this writing, the dosage amount and location has
not changed. |
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Results: |
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The Operators Log at the St. Augustine Wastewater Treatment Plant
# I noted a drastic change in both the facility settling time and
turbidity during the first 24 hours of use. Due to the quicker
settling time and clearer water, it was determined by facility
personnel to reduce the amount of polymer introduced into the
treatment works. |
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Facility records indicate that 138.78 tons of sludge was generated
and disposed of during the first 60 days ofuse. This compares to
324.69 tons of sludge generated previously during the same flow,
weather, and operational conditions. This decrease in the amount
of sludge generated represents a reduction of over 57%.
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Facility records indicate that during the first 60 days ofuse, the
belt press required 47 total man hours to operate. This compares
to 206 total man hours previously required to operate the belt
press during a period with similar flow, weather, and operational
conditions. This decrease in the amount of man hours required to
operate the belt press represents a reduction in labor of over
77%. Facility records also indicate that during the first 60 days
of use, the amount of polymer used as a part of the treatment
process declined from an average of 87 gallons per month to an
average of 37 gallons per month, a reduction of over 57%.
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In order to verify the results attained, the use of PX-700TM was
hatted on August 8, 1998. Facility personnel continued to gather
data for comparison and entered observations into the daily log.
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It quickly became apparent to all involved, that the use of
PX-700TM significantly reduced the amount of sludge generated by
the St. Augustine Wastewater Treatment Plant # 1. |
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City personnel decided to permanently put PX-700TM back on line on
August 25, 1998. |
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Since that time, Dave Parker, Wastewater Superintendent has
indicated that the total cost to the City of St. Augustine for
sludge disposal is down 75%. |
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The City of St. Augustine had continued to purchase and use
PX-700TM through the date of this writing. |
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Total Cost of Sludge Transport and Disposal |
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Prior to Use of PX-700 |
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$250,000.00 Annually |
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With Use of PX-700 |
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$62,000.00 Annually |
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This amounts to a 75% reduction in the total annual cost
of transport and disposal of sludge. |
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$300,000.00
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Prior to Use of
PX- 700 |
With Use of PX-
700 |
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$250,000.00
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$200,000.00
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$150,000.00
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$100,000.00
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$50,000.00
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Total Cost of Sludge Generated |
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Prior to Use of PX-700 |
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833 Tons Annually |
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With Use of PX-700 |
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358 Tons Annually |
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This amounts to a 57% reduction in the total amount of
sludge generated |
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2,000 Tons |
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Prior to Use of
PX- 700 |
With Use of PX-
700 |
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1,500 Tons |
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1,000 Tons |
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750 Tons |
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500 Tons |
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250 Tons |
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