Flocculator Tank Construction History
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h1. Flocculator Tank Construction History {float:right|border=2px solid black|width=200px} {anchor:tank}[!Pilot Plant^Starting Tank.jpg|width=200px!|Pilot Plant^Starting Tank.jpg] h5. Plastic Tank that was the starting design constraint for the vertical flow hydraulic flocculator. {float} h3. |
Spring
...
2007
Design
The construction of the tank was started during the Spring 2007 semester. The floc tank was designed to be contained in a polyethylene tank of dimensions 182.9 cm × 91.4 cm × 121.9 cm (length × width × height) with a wall thickness of about 0.8 cm.#tankThe design goal was to divide the tank into 3 separate sections, basically condensing a long, narrow flocculation tank into a more compact space by snaking the flow back and forth. The initial design divided the total minimum mixing value (20,000) evenly among the three sections, with each section having an even velocity gradient (G) of 45 s-1.
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h4. Design
The construction of the tank was started during the Spring 2007 semester. The floc tank was designed to be contained in a polyethylene tank of dimensions 182.9 cm × 91.4 cm × 121.9 cm (length × width × height) with a wall thickness of about 0.8 cm.[#tank]The design goal was to divide the tank into 3 separate sections, basically condensing a long, narrow flocculation tank into a more compact space by snaking the flow back and forth. The initial design divided the total minimum mixing value (20,000) evenly among the three sections, with each section having an even velocity gradient (G) of 45 s-1.
{float:right|border=2px solid black|width=200px}
{anchor:section dividers}[!Pilot Plant^tank dividers.jpg|width=200px!|Pilot Plant^tank dividers.jpg]
h5. Plastic dividers that create three sections for a serpentine flow path through the tank.
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{float:right|border=2px solid black|width=200px} {anchor:flow path top view}[!Pilot Plant^tank flow path.jpg|width=200px!|Pilot Plant^tank flow path.jpg] h5. The serpentine flow path can be clearly seen in the top view of the flocculator. {float} |
In
...
order
...
to
...
divide
...
the
...
tank
...
into
...
three
...
sections,
...
a
...
divider
...
system
...
had
...
to
...
be
...
built
...
in
...
the
...
tank.
...
Originally
...
it
...
was
...
planned
...
to
...
purchase
...
two
...
plastic
...
sheets
...
to
...
function
...
as
...
the
...
dividers
...
and
...
weld
...
them
...
vertically
...
into
...
the
...
tank.
...
This
...
option
...
was
...
soon
...
rejected
...
due
...
to
...
two
...
major
...
concerns:
...
difficulties
...
of
...
welding
...
inside
...
the
...
cramped
...
spaces
...
of
...
the
...
tank,
...
and
...
lack
...
of
...
strength
...
in
...
the
...
welds.
...
After
...
much
...
contemplation,
...
the
...
maintenance
...
shop
...
proposed
...
a
...
plan
...
to
...
build
...
a
...
structure
...
that
...
would
...
provide
...
support
...
and
...
flexibility.
...
The
...
sketch
...
shows
...
that
...
the
...
...
were
...
welded
...
onto
...
a
...
base
...
slab
...
and
...
the
...
completed
...
module
...
was
...
placed
...
into
...
the
...
tank.
...
A
...
port
...
hole
...
(hole
...
through
...
which
...
water
...
flows
...
between
...
sections)
...
was
...
cut
...
in
...
each
...
divider
...
prior
...
to
...
welding.
...
The
...
dimensions
...
of
...
the
...
dividers
...
are
...
approximately
...
182.9
...
cm
...
x
...
121.9
...
cm
...
with
...
a
...
0.6
...
cm
...
thickness.
...
The
...
choice
...
of
...
material
...
for
...
the
...
dividers
...
as
...
well
...
as
...
the
...
base
...
slab
...
is
...
high-density
...
polyethylene
...
and
...
was
...
specifically
...
chosen
...
for
...
its
...
non-reactive
...
property
...
in
...
water
...
treatment
...
process,
...
and
...
most
...
importantly
...
its
...
ability
...
to
...
be
...
welded.
...
Below
...
is
...
a
...
list
...
of
...
fixed
...
parameters
...
(or
...
"givens")
...
and
...
the
...
values
...
of
...
G
...
to
...
be
...
used
...
in
...
the
...
initial
...
setup.
...
Givens:
...
- Tank
...
- dimensions:
...
- 182.9
...
- cm
...
- ×
...
- 91.4
...
- cm
...
- ×
...
- 121.9
...
- cm
...
- Tank
...
- wall
...
- thickness:
...
- 0.8
...
- cm
...
- Tank
...
- divided
...
- into
...
- 3
...
- sections
...
- (serpentine
...
- flow
...
- path)
...
- Total
...
- minimum
...
- mixing
...
- value
...
- (Gθ)
...
- =
...
- 20,000
...
- Initially
...
- 1st,
...
- 2nd,
...
- and
...
- 3rd
...
- sections
...
- of
...
- tank
...
- to
...
- have
...
- velocity
...
- gradient
...
- (G)
...
- of
...
- 45
...
- s-1
...
Installation
...
of
...
Tank
...
Constant
...
communication
...
with
...
the
...
Cornell
...
Water
...
Treatment
...
Plant
...
was
...
needed
...
to
...
attempt
...
to
...
integrate
...
the
...
pilot
...
plant
...
into
...
their
...
facility.
...
Some
...
modifications
...
was
...
necessary
...
after
...
transportation
...
and
...
set
...
up
...
in
...
the
...
tank
...
at
...
the
...
plant.
...
A
...
frame
...
was
...
fabricated
...
to
...
hold
...
the
...
rapid
...
mix
...
in
...
place
...
on
...
the
...
side
...
of
...
the
...
tank.
...
The
...
inlet
...
pipe
...
had
...
to
...
be
...
redirected
...
to
...
fit
...
into
...
the
...
rapid
...
mix
...
pipe.
...
Directing
...
the
...
inlet
...
pipe
...
directly
...
straight
...
down
...
into
...
the
...
top
...
of
...
the
...
rapid
...
mix
...
pipe
...
would
...
give
...
us
...
the
...
maximum
...
flow
...
from
...
that
...
pipe.
...
The
...
outlet
...
pipe
...
was
...
reconstructed
...
to
...
prevent
...
leakage.
...
Water
...
from
...
the
...
treatment
...
plant
...
is
...
directed
...
to
...
us
...
before
...
treatment.
...
After
...
the
...
water
...
is
...
treated
...
in
...
our
...
system
...
the
...
effluent
...
exits
...
the
...
tank
...
and
...
reenters
...
the
...
treatment
...
plant
...
at
...
the
...
same
...
point
...
through
...
a
...
nearby
...
drain.
...
Spring
...
2008
...
The
...
first
...
half
...
of
...
the
...
Spring
...
2008
...
semester
...
was
...
spent
...
making
...
significant
...
modifications
...
to
...
the
...
flocculation
...
tank.
...
When
...
the
...
tapered
...
baffle
...
configuration
...
was
...
installed
...
in
...
the
...
flocculator
...
the
...
baffles
...
around
...
the
...
port
...
holes
...
were
...
set
...
farther
...
apart
...
than
...
in
...
the
...
original
...
configuration
...
and
...
thus
...
the
...
port
...
holes
...
had
...
to
...
be
...
enlarged
...
to
...
ensure
...
flocs
...
were
...
not
...
being
...
broken
...
up.
...
The
...
holes
...
were
...
enlarged
...
so
...
that
...
the
...
port
...
hole
...
area
...
was
...
equal
...
to
...
the
...
cross-sectional
...
area
...
of
...
water
...
below
...
a
...
top
...
baffle.
...
Sludge
...
that
...
had
...
settled
...
to
...
the
...
bottom
...
of
...
the
...
tank
...
was
...
removed
...
and
...
tank
...
was
...
cleaned
...
before
...
it
...
was
...
started
...
up
...
for
...
the
...
first
...
time
...
that
...
semester.
...
Additional
...
sand
...
was
...
added
...
to
...
the
...
bottom
...
of
...
the
...
tank
...
before
...
the
...
baffles
...
were
...
placed
...
in.
...
The
...
purpose
...
of
...
the
...
sand
...
was
...
to
...
block
...
or
...
greatly
...
reduce
...
flow
...
in
...
the
...
space
...
between
...
the
...
divider
...
module
...
and
...
tank
...
wall.
...
It
...
was
...
also
...
desired
...
that
...
the
...
sand
...
reduce
...
bypass
...
of
...
water
...
underneath
...
the
...
baffles.
...
When
...
the
...
tank
...
was
...
turned
...
on
...
it
...
was
...
determined
...
that
...
a
...
significant
...
amount
...
of
...
flow
...
was
...
still
...
by-passing
...
the
...
system
...
and
...
flowing
...
under
...
the
...
divider
...
module,
...
despite
...
the
...
several
...
inches
...
of
...
sand
...
that
...
were
...
added
...
to
...
the
...
third
...
section.
...
It
...
was
...
noticed
...
when
...
the
...
tank
...
was
...
filled
...
that
...
that
...
the
...
first
...
and
...
third
...
sections
...
were
...
filling
...
at
...
almost
...
the
...
same
...
rate.
...
Before
...
caulking
...
was
...
done
...
additional
...
sand
...
was
...
added
...
to
...
the
...
bottom
...
of
...
the
...
tank
...
in
...
the
...
third
...
section
...
to
...
try
...
and
...
see
...
if
...
significant
...
enough
...
head
...
loss
...
could
...
be
...
created
...
in
...
the
...
tank
...
to
...
cause
...
most
...
of
...
inflow
...
to
...
follow
...
the
...
correct
...
flow
...
path.
...
Upon
...
refilling
...
the
...
tank
...
the
...
upflow
...
was
...
still
...
noticed.
...
A
...
clear
...
PVC
...
tube
...
was
...
inserted
...
into
...
the
...
gap
...
and
...
the
...
difference
...
in
...
water
...
height
...
in
...
the
...
tube
...
and
...
in
...
the
...
tank
...
was
...
measured.
...
It
...
was
...
found
...
to
...
be
...
about
...
¾".
...
This
...
was
...
deemed
...
significant,
...
however
...
caulking
...
was
...
still
...
deemed
...
necessary.
...
The
...
tank
...
was
...
drained,
...
cleaned
...
and
...
cleared
...
of
...
sand
...
again
...
so
...
that
...
caulk
...
could
...
be
...
added
...
to
...
seal
...
the
...
gap.
...
Summer
...
2008
...
Several
...
changes
...
were
...
implemented
...
while
...
the
...
tank
...
was
...
being
...
caulked.
...
A
...
digital
...
flow
...
meter
...
was
...
added
...
to
...
the
...
inlet
...
pipe.
...
This
...
meter
...
was
...
put
...
in
...
place
...
for
...
several
...
purposes.
...
First,
...
it
...
was
...
added
...
to
...
make
...
it
...
easier
...
to
...
alter
...
the
...
plant
...
flow
...
rate
...
without
...
draining
...
and
...
refilling
...
the
...
tank
...
to
...
determine
...
the
...
flow
...
rate.
...
Secondly
...
it
...
was
...
added
...
to
...
provide
...
instant
...
feedback
...
to
...
the
...
flow
...
measuring
...
bucket
...
that
...
was
...
added
...
to
...
the
...
inlet
...
of
...
the
...
tank.
...
The
...
structural
...
changes
...
needed
...
to
...
be
...
implemented
...
the
...
flow
...
measuring
...
bucket
...
were
...
also
...
implemented
...
while
...
the
...
tank
...
was
...
being
...
caulked.
...
These
...
changes
...
included
...
building
...
a
...
brace
...
and
...
stand
...
for
...
the
...
bucket
...
to
...
sit
...
over
...
the
...
tank,
...
above
...
the
...
first
...
baffle.
...
In
...
order
...
to
...
accommodate
...
the
...
bucket
...
the
...
rapid
...
mix
...
tube
...
had
...
to
...
be
...
cut
...
and
...
extended
...
so
...
that
...
instead
...
of
...
flowing
...
directly
...
into
...
the
...
tank
...
it
...
flowed
...
into
...
the
...
bucket
...
and
...
then
...
the
...
bucket's
...
weir
...
deposited
...
water
...
into
...
the
...
tank.
...
Alum
...
inlet
...
also
...
had
...
to
...
be
...
extended
...
upward
...
because
...
after
...
the
...
rapid
...
mix
...
extension
...
the
...
alum
...
was
...
entering
...
lower
...
than
...
the
...
raw
...
water
...
inlet
...
pipe
...
and
...
this
...
could
...
cause
...
back
...
flow
...
down
...
the
...
alum
...
tube
...
not
...
to
...
mention
...
leaking
...
in
...
this
...
part
...
of
...
the
...
rapid
...
mix
...
set-up
...
that
...
was
...
not
...
glued
...
down.
...
The
...
raw
...
water
...
inlet
...
after
...
structural
...
modifications
...
were
...
made
...
to
...
the
...
rapid
...
mix
...
tube
...
and
...
bucket
...
was
...
in
...
place.
...
The
...
final
...
modification
...
that
...
was
...
made
...
in
...
the
...
tank
...
was
...
to
...
add
...
a
...
submersible
...
light
...
to
...
the
...
third
...
section.
...
This
...
florescent
...
light
...
was
...
added
...
to
...
allow
...
us
...
to
...
be
...
able
...
to
...
see
...
flocs
...
in
...
the
...
water.
...
The
...
light
...
was
...
attached
...
to
...
a
...
pole
...
and
...
then
...
suspended
...
a
...
few
...
feet
...
below
...
the
...
surface
...
of
...
the
...
water.
...
This
...
light
...
was
...
held
...
in
...
place
...
by
...
two
...
ring
...
stand
...
clamps
...
attached
...
to
...
the
...
light
...
pole
...
and
...
to
...
two
...
separate
...
bracing
...
poles
...
that
...
rested
...
across
...
the
...
section
...
dividers.