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The State of Michigan has amended Part 117 of the
Septage Waste Servicers, of the Natural Resources and Environmental
Protection Act, 1994, P.A. 451, to require the development of an Operating
Plan describing the receipt of septage wastes.
The Rollin & Woodstock Plant (R-W WWTP) has contracted with Hazen & Sawyer
-Environmental Engineers to study the head works capacity. Because of the
R-W WWTP minimal loadings, a study was approved by DEQ for the plant to
receive 6,000 gallons per day of septage for 90 days. The study was
completed in January of 2007, with little or noticeable impact to plant
discharge.
The R-W WWTP will continue to receive Septage during the interim period
during the design phase of a permanent receiving station at a rate of 6,000
to 8,000 gallons per day and up to 18,000 gallons per with MDEQ approval of
submitted plan.
A new operating plan includes and describes: the location, hours of
operation, limits to acceptance of domestic septage, fee structure, service
area and other conditions applicable to the receipt and acceptance of
domestic septage.
Copies of the operating plan will be available at the Lenawee County Drain
Commissioner’s Office at 320 Springbrook Ave. Suite 102 Adrian Michigan
49221, between the hours of 8:00 am and 4:30 pm; Monday through Friday. It
will also be available on the Lenawee County Drain Commissioner’s website at
(www.lenaweedrain.com).
Written comments concerning this plan should be submitted by May 31, 2007 to
the attention of
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Jack Dillon
Lenawee County Drain Commissioner’s Office
Sewer & Water Superintendent
320 Springbrook Ave. Suite 102
Adrian, MI 49221 |
For additional information, please call Jack Dillon or Stephen R. May at
517-264-4696.
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A pilot program was completed at the Rollin &
Woodstock WWTP to determine the capacity of the treatment plant to accept
septage. The second goal of the program was to gather data on the septage
characteristics and study the effects of the septage on the discharge
effluent of the plant. MDEQ allowed the plant to accept 6,000 gallon of
septage per day which was screened and pumped to aerobic digesters that were
not in use. The dissolved oxygen was kept at or above 2 mg/l. After 60 days
into the study the amount of septage was increased to 8,000 gallon per day.
This had minimal effect on the plant. We did not witness any odors coming
from the process. The supernatant that was taken from the process and pumped
back to the head-works of the plant showed no effects on the discharge of
the plant.
Project Plan Conclusion
The plant has two aerobic digesters with a capacity of 50,000 gallons each.
The pilot study demonstrated that one digester could treat 8,000 gallons per
day of septage with no adverse effects on the plant or the discharge. In the
new protocol, the septage will be divided between both aerobic digesters
which will allow 16,000 – 18,000 gallons per day of septage to be processed
at the plant. The septage would only be sent to the solids handling portion
of the plant. The supernatant would be pumped to the head-works of the plant
which would be controlled by the operator. If there should be a problem with
the septage or the plant discharge, the plant would discontinue to accept
septage.
Mode of Operation
The project plan is to construct a building at the west end of the gravity
thickeners and install the JWC Honey Monster Septage Receiving System. The
septage hauler will drive up to the building and connect to a (4) inch stand
pipe located next to the drive. The hauler will then insert a card (that
will be issued to him by the Lenawee County Drain Commissioner) to start the
screen and open the inlet valve to the screen. The septage will flow through
the screen into a pumping station located at the gravity thickeners. The
station will turn on at a preset level and transfer the septage to the
predetermined digester or digesters.
The septage will be mixed with treated sludge in the primary digesters.
Sludge will be transferred daily from the primary digesters to a decant
tank, there the sludge will be allowed to settle and the solids and
supernatant will separate and the supernatant will be fed back to the
head-works of the plant. The solids that settle will be pumped to a storage
digester and mixed with waste activated sludge from the plant process. The
storage digester will be decanted and the Bio-solids will be concentrated in
preparation for land application at an approved site. All Bio-solids will
conform with State regulations and in accordance with the R-W WWTP
Bio-solids Management Plan.
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Because of winter months the primary digesters and
decant tank will be covered and odor control will be installed. Should a
hauler have an emergency and have to unload at the plant, overflow will be
sent to the gravity thickener and will be fed to the digester at the
operator’s discretion or during low flows of septage. The gravity thickeners
will give the plant 50,000 gallons of emergency storage. This cover will
keep odor in control and keep the digesters from freezing during winter
months.
The supernatant will be fed back to the head-works at a rate so not to
affect the plant discharge quality. Should the system develop a problem all
septage activities will be suspended until the problem is corrected. The
septage program at no time will diminish the plants ability to treat the
sewage coming to the plant from its customers.
Septage Hauler Responsibilities
1. Haulers will complete a chain of custody
documenting the location and date pumped
2. The hauler will have a permit to unload at the
R-W WWTP by having a card (issued by
the Lenawee County Drain
Commissioner) to start the receiving station.
3. The card will allow R-W WWTP to keep track of
the unloading flow rate and the total
gallons unloaded.
4. The hauler must be licensed and insured.
5. Any septage load not meeting domestic quality
that may present some type of
characteristic not
compatible with the plant may be refused.
6. The hauler will have a compatible connection
to R-W WWTP receiver.
7. The hauler must be able to pressurize the
truck tank to clean out the connection and
piping going to the
screen. This will help prevent freezing in winter and septage being
spilled on the ground.
8. It is the haulers responsibility to report any
problems with equipment to the R-W WWTP staff.
9. The hauler will enter the North gate at the
plant drive West around the storage tanks turn
South and drive up to the
inlet pipe to the screen, after unloading they will proceed South than
turn East following the
drive and leave by way of the North gate.
The Responsibilities of the Operator at R-W WWTP
1. Will keep equipment in proper working
condition.
2. Will be inspected on a daily basis.
3. The screen building will have a gas detector
with audio and visual alarm warning system.
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4. Odor control will be controlled by vent fans
which will run when screen is started or
a person entering the
building or detection limits are out of compliance for safe entrance.
5. The hauler will be billed by the Lenawee
County Drain Commissioner on a monthly basis.
Hydraulic and Organic Loading Capacity
The septage will not flow through the head-works, but will enter the sludge
handling and processing streams. The supernatant will be pumped back to the
head-works. Should the supernatant affect the plant, the supernatant will be
shut off and the flow will be sent to the Equalization Basin.
Section D of the Operating Plan shows the loadings and capacities.
The Organic loading on the head-works was contracted to Hazen & Sawyer
Engineers;
Table 1 shows the projected loading and available capacities
for the plant in the year of 2025.
Table 2 shows the loading of the supernatant going back to the
head-works at volumes equal to the septage being accepted. The Peak Day is
the highest amount sent to the head-works in one day.
Table 3 shows the same loadings in pounds per day at different
loadings volumes.
Table 4 shows the capacity available for Rollin & Woodstock
future flows.
The Supernatant should have minimal effect on the plant discharge.
*tables located at end of document
Digester Capacity
The next page in section (D) shows the digester volumes and
capacities of the plant. Total plant capacity includes hauling bio-solids
two times per year achieving a total volume of 1,662,000 million gallons per
year. Total septage that could be received is 4,320,000 million gallons per
year. The plant could expect to see 70% to 76% reduction in volume by solids
separation or (decanting) in the digesters and sludge storage. This
reduction would leave 787,200 gallons for future capacity. The plant has a
belt thickener and two gravity thickeners if more capacity is needed to meet
future flows.
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The Rollin & Woodstock Wastewater Treatment Plant
receives domestic sewage from the townships of Rollin and Woodstock and the
Village of Addison, as well as domestic septage from Lenawee County and
Hillsdale County. The Plant is operated by the Lenawee County Drain
Commissioner, under the authority of the Rollin & Woodstock Sanitary Drain
Drainage Board. Tom Gillenwater is the current Superintendent. The septage is
trucked to the septage receiving facility by independent haulers.
The State of Michigan has amended Part 117 of the Septage Waste Servicer’s,
of the Natural Resources and Environmental Protection Act, 1994, P.A. 451,
to require the development of an Operating Plan describing the receipt of
septage wastes. This plan is submitted in response to this requirement.
1.) The Rollin & Woodstock WWTP service area and capacities.
The Rollin & Woodstock WWTP is located at 6100 Sorby Road, Addison, Michigan
49220. The Rollin & Woodstock Plant (R-W WWTP) receives sewage from Devils
Lake and Round Lake areas located in the townships of Rollin and Woodstock
and the Village of Addison.
The R-W WWTP is regulated under NPDES permit MI0027669 and is authorized to
treat a maximum flow of 1.2 MGD with a peak flow of 3 MGD.
2.) Domestic Septage Waste
The R-W WWTP will receive domestic septage from the counties of Lenawee and
Hillsdale in accordance with State laws. No other type of septage will be
received at the R-W WWTP including, food establishment, commercial, portable
toilet, or recreational vehicle waste.
3.) Service Area of Septage
The R-W WWTP will receive septage primarily from Lenawee County and
Hillsdale County. State Law requires any septage hauler pumping septage
within 15 miles of the R-W WWTP, and the hauler does not have 50,000 gallons
of storage and can not land apply they are required to bring that septage to
R-W WWTP receiver station. The septage receiving service area will increase
to a 25 mile radius from the plant in 2010.
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4.) Other Conditions for Receiving Septage Waste
The following additional conditions have been established for the receipt of
septage waste.
a. All trucks must be licensed through the
Michigan Department of Environmental Quality
(MDEQ) as a
condition of applying for permission to discharge.
b. Each truck must have a written chain of
custody to verify where the septage was pumped
and to confirm
origin of the septage.
c. All trucks shall be equipped to connect
to the R-W WWTP receiving facility station.
d. Each company will pre-apply for permit
to discharge to the plant, so that R-W WWTP
can keep track of
gallons unloaded, feed rates to the screen.
e. The R-W WWTP may withhold discharge at
any time should plant conditions warrant
or if it has
received the maximum amount for that day.
f. The maximum discharge limit for a single
day will be 18,000 gallons, Monday through
Friday, 7:30 am to
4:00 pm. except holidays.
g. The R-W WWTP may receive more than
18,000 gallons per day on an emergency basis.
The additional
septage will be diverted to one of two gravity sludge thickeners, and
processed during
the weekend or during slow periods.
h. At no time will septage be allowed to
deteriorate the discharge quality of the plant
process. Only the
dewatering (supernatant) will be allowed back to the head works of
the plant. The
septage will be kept separated from the normal operation of the plant to
receive sewage from
the Townships and the Village.
i. The Card access will allow the R-W WWTP
to monitor the septage flow and provide
information for
billing and prevent unauthorized use.
j. Should R-W WWTP have a problem, flow or
septage or supernatant would be sent to
the EQ basin for
pre-treatment.
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4.) Fee Structure to Dispose of Septage for
Treatment
Each hauler will be charged $ 70.00 per 1,000 gallons or $.07 cents per
gallon.
a. $30.00 - operations and maintenance
b. $27.00 - debt service of loan
c. $10.00 - tank storage lease - R-W WWTP
d. $3.00 - miscellaneous
5.) Odor Control
Plant has had no odor problems, the screen and primary digesters will be
covered, and odor control measures will be installed if needed.
6.) Screenings
All screening are washed with plant non-potable water in the screen, placed
in plant drying beds to dry and will be taken to land-fill.
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DIGESTER
CAPACITY
| 1) Primary Digesters = 2 tanks @ 50,000 gal. each |
100,000 gallons |
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| 2) Decant Tank = 1 tank @ 20,000 gal. |
20,000 gallons |
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| 3) 3 Sludge Holding = 3 @ 237,000 gal. each
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711,000 gallons |
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| Total Treatment/Storage Capacity |
831,000 gallons |
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Bio-Solids will be applied Spring and Fall
doubling our storage capacity.
Total Holding Capacity
1,662,000 gallons per year
Septage Receiving Capacity
The plant may receive up to 18,000 gallons/day/ M-F.
1.) 18,000 gal. x 20 days/month x 12 months/year
= 4,320,000 gallons/year.
2.) The Pilot study just completed by R-W WWTP
demonstrated a 78% reduction in
volume can be
expected
3.) 410,750 gal of septage was received during
our study. We decanted back to the head
works of the plant
323,130 gallons of supernatant.
a.) 323,130gal /
410,750 x 100 = 78% reduction in volume.
b.) The plant
wasted from the treatment process a total of 49,720 gallon of waste
activated sludge (WAS) during our study.
c.) 410,750 gal.
septage + 49,720 was = 460,470 total gallons of septage and
waste activated sludge was received by the solids handling portion of the
treatment plant during our study.
d.) 323,130 gal /
460,470gal x 100 = 70% reduction in sludge volume.
4.) 4,320,000 gallons received/year x 70%
reduction in volume = 3,024,000 gallon
of supernatant will
be sent back to the head works to be processed by the plant,
with 1,296,000
gallons going into sludge holding.
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5.) The digested sludge
in holding is at a concentration of 2.7%* solids. Bio- solids are
applied at a concentration of 4% solids or higher. The Sludge volume in
holding
tanks can be concentrated even more.
a) 1,296,000
x 2.7% solids / 4% solids = 874,800 gallons
b.) 1,296,000 –
874,800 = 421,200 gallons of supernatant sent back to
head works of the plant.
6.) 874,800 gallons of sludge generated and
1,662,000 gallons of storage the plant
will have a
remaining capacity of 787,200 gallons of sludge storage
.Sludge Capacity unused per year = 787,200 gallons
* see section (J)
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