Wastewater Treatment Plants for Flows
<1,500 US gpd
Tanks-A-Lot manufactures and
distributes the Singulair® Model 960
patented wastewater treatment plants
Total holding capacity of the system shall provide
a minimum of 48 hour retention of the daily flow. The pretreatment chamber shall
provide at least 18 hour retention, the extended aeration chamber shall provide
at least 24 hour retention, and the clarification chamber shall provide at least
6 hour retention. The non-mechanical flow equalization device shall increase
each individual chamber and total system retention time in direct proportion to
loading. Design of the system shall include a compartmented tank and
non-mechanical flow equalization device to insure successful treatment
performance without upset even when the significant runoff period is six hours.
Hydraulic design considerations of the system and flow equalization device shall
be such that intermittent peak flow factors as high as four shall not upset
hydraulic reliability within the system.
The pretreatment chamber shall be an integral part
of the wastewater treatment system. All domestic wastewater is preconditioned
and flow equalized while passing through the pretreatment chamber prior to being
introduced to the extended aeration chamber. The outlet of the pretreatment
chamber shall be equipped with a discharge tee that extends vertically into the
liquid so that only the preconditioned equalized flow from the center area of
the chamber is displaced to the extended aeration chamber. The discharge tee and
transfer port shall be of adequate size to handle a peak flow factor of four
without restricting the outlet and disturbing hydraulic displacement to the
extended aeration chamber. A removable inspection cover shall be cast into the
top of the pretreatment chamber to allow tank and transfer tee inspection. As a
safety measure, the uncovered opening shall be small enough to insure that the
tank cannot be entered for inspection or service.
The extended aeration chamber shall provide in excess
of twenty-four hour retention of the equalized daily flow. The chamber shall be
of sufficient size to provide a minimum of eighty cubic feet of tank capacity
per pound of applied BOD. The aeration chamber length-width-depth ratio shall be
designed to insure uniform tank mixing and provide optimum treatment. The
aeration chamber(s) shall be an integral part of the system flow path and
constructed of properly reinforced five thousand PSI, twenty-eight day
compression strength precast concrete. All castings used to construct the
precast concrete tankage shall be monolithic units with external and internal
walls incorporated into each section.
The final clarification chamber shall
consist of five functionally independent zones operating together to provide
satisfactory settling and clarification of the equalized flow. An inlet zone
shall be provided and shall dissipate transfer turbulence at the flow inlet of
the clarification chamber. Its performance shall also eliminate turbulence in
other zones of the clarifier. Liquid shall be hydraulically displaced from the
hoppered walls and return these solids via the inlet zone to the aeration
chamber. As solids are removed, liquid is displaced to the hopper zone of the
clarifier. In this zone, settling by gravity takes place. Three of the four
sidewalls are slanted to form a hopper which directs all settled material back
to the sludge return zone. Clarified liquid from the hopper zone shall be
displaced into the final settling zone to provide additional clarification of
the liquid. The liquid is finally displaced to the outlet zone for final
filtration and discharge from the system. Non-mechanical equalization of the
flow, through all five independent zones, shall provide optimal settling and
clarification.
Each Modal 96 Singulair® aerator shall be installed in
a concrete aerator mounting casting above the aeration chamber. It shall include
plated mounting brackets, moisture resistant electrical connector, fractional
horsepower motor, flexible drip shield, molded plastic foam restrictor,
stainless steel aspirator shaft and molded glass-filled nylon aspirator. Only
the stainless steel aspirator shaft and molded nylon aspirator shall be
installed in contact with the liquid. There shall be no submerged electrical
motors, bearings, or fixed air piping in the aeration system. Singulair® aerator
motors shall be designed not to exceed the motor nameplate rating when installed
and operated as recommended for the system. The fractional horsepower aerator
motor shall be equipped with a foam restrictor to protect the motor against high
water and foam.
The fresh air supply for the Singulair® system
shall be provided through a molded plastic vent assembly cast into the concrete
access cover above the aerator. Fresh air shall be drawn into the vent assembly
through slotted screening ports molded into the vent body and circulated through
the drip shield into the aerator intake port. Fresh air shall be drawn down the
hollow motor shaft through the intermediate shaft and stainless steel aspirator
shaft for infusion into the liquid through the molded nylon aspirator. The
plastic aerator vent assembly shall be an epoxy-joined, two-piece assembly to
eliminate the possibility of cap loss or removal. The concrete access cover
shall weigh in excess of seventy-five pounds to discourage unauthorized access.
A Bio-Kinetic® system shall be installed in the
system mounting casting(s) above the outlet zone of the clarification chamber.
Each Bio-Kinetic® system shall provide non-mechanical flow equalization through
all plant processes including pretreatment aeration, clarification, tertiary
filtration, chlorination and dechlorination to insure acceptable treatment
results. The assembly shall be supplied with locking lugs and removable cover
and shall consist of a design flow and peak flow micronically molded filter,
baffled perimeter settling zone, non-mechanical flow equalization, flow
distribution deck, lifting handles, level indicator adjustment lugs, optional
chlorination feed tube, unbaffled perimeter settling zone, solids contact zone,
vertical inlet zone compartmented settling zone consisting of thirty-seven
baffled chamber plates, effluent stilling well, final discharge zone adjustable
outlet weir, optional dechlorination feed tube, outlet zone, sealing grommet and
discharge flange with stainless steel locking clip.
All components shall be manufactured from inert synthetic materials, rubber
or corrosion resistant stainless steal, assembled in circular fashion and
connected to a plastic outlet coupling. The outlet coupling shall accept a 4"
diameter, Schedule 40, PVC discharge pipe. Each Bio-Kinetic® system shall be
installed in a vertical position so that the inverts of the design flow
equalization ports are located at the normal liquid level of the clarifier. If
intermittent flow rates exceed the capacity of the design flow ports, flow shall
be held upstream until the intermittent flow dissipates or continues to
increase. If the intermittent flow continues to increase it may reach a pair of
sustained flow equalization ports. With four ports in use flow through the
system increases while continuing to provide non-mechanical flow equalization to
all upstream and downstream processes. Peak flow equalization ports are supplied
but should not be required in a properly sized system.
The wastewater treatment system shall include a
non-mechanical, demand use, flow equalization device. The device shall control
normal residential flow rates and reduce typical residential flow surges (e.g.
shower @ 10 minutes duration, bathtub discharge @ 5 minutes duration, clothes
washer discharge @ 2 minutes duration, and dishwasher discharge @ 2 minutes
duration). The flow equalization rate shall be dependent on the specific loading
pattern and the duration of flow surges. At the NSF Standard 40 design loading
schedule, minimum performance of the device shall equalize daily flow an average
of 44%.
A Bio-Static® sludge return shall be installed
in the cast-in-place opening(s) in the aeration/clarification chamber wall to
provide positive return of settled solids. Each Bio-Static® sludge return shall
be located such that inlet end invert, in the aeration chamber, is mounted one
inch below the invert of the design flow equalization ports in the Bio-Kinetic®
tertiary treatment device (submerged one inch below design flow liquid level).
Aeration chamber hydraulic currents shall enter the sludge return(s) and be
directed through the Bio-Static® device into the second zone of the
clarification chamber. The hydraulic current containing the settled and re-suspended
sludge shall be directed through the clarification chamber inlet
zone and returned to the aeration chamber. The Bio-Static® sludge return shall
accomplish re-suspension and return of settled solids without disturbing the
clarified liquid in the final settling zone and outlet zone. Each Norweco
Bio-Static® sludge return shall be manufactured from inert synthetic material
and be permanently mounted in the aeration/clarification chamber wall without
separate external fasteners or mounting brackets. Each sludge return shall be a
passive hydraulic device with no moving parts.
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