...
The
...
AguaClara
...
Technology
...
A
...
Brief
...
Overview
...
of
...
the Technology
| Wiki Markup |
|---|
Technology {float:right|border=2px solid black|width=300px} [!Ojojona Photos^0015_08_094.jpg|width=300px!|Ojojona Photos] {float} |
The
...
AguaClara
...
technology
...
is
...
an
...
innovative
...
form
...
of
...
flocculation-sedimentation
...
that
...
has
...
been
...
adapted
...
at
...
Cornell
...
University
...
to
...
operate
...
without
...
electrical
...
input.
...
Unlike
...
conventional
...
flocculators,
...
which
...
rely
...
on
...
large
...
motor-driven
...
stirring
...
devices,
...
ours
...
create
...
mixing
...
solely
...
with
...
gravitational
...
forcing
...
through
...
turning
...
channels.
...
The
...
chemical
...
dosing
...
for
...
the
...
plants
...
is
...
all
...
accomplished
...
by
...
using
...
simple
...
float
...
valve-regulated
...
constant
...
head
...
devices,
...
and
...
the
...
plant
...
flow
...
rates
...
are
...
measured
...
and
...
controlled
...
using
...
riser
...
pipes
...
with
...
calculated
...
patterns
...
of
...
holes
...
drilled
...
through.
...
Sites
...
for
...
AguaClara
...
plants
...
are
...
selected
...
based
...
on
...
the
...
presence
...
of
...
a
...
distribution
...
system
...
and
...
the
...
apparent
...
commitment
...
of
...
the
...
town
...
to
...
the
...
project.
...
Candidate
...
sites
...
must
...
have
...
a
...
distribution
...
system
...
in
...
place
...
that
...
will
...
be
...
able
...
to
...
deliver
...
the
...
treated
...
water
...
to
...
homes.
...
AguaClara
...
is
...
responsible
...
for
...
the
...
research,
...
design,
...
capacity
...
building,
...
and
...
training
...
going
...
into
...
each
...
plant,
...
but
...
construction
...
is
...
supervised
...
by
...
a
...
partner
...
organization
...
and
...
plant
...
operations
...
and
...
maintenance
...
are
...
the
...
responsibility
...
of
...
the
...
municipality
...
or
...
local
...
water
...
board.
...
A
...
Detailed
...
Plant
...
Tour
...
The
...
entrance
...
tank
...
to
...
the
...
rapid mix
| Wiki Markup |
|---|
mix {float:left|border=2px solid black|width=300px} [!Tamara Report Photos^Grit Chamber Figure 6.jpg|width=300px!|Tamara Report Photos] {float} |
Source
...
water
...
flows
...
via
...
the
...
pre-existing
...
transmission
...
line
...
to
...
the
...
entrance
...
tank
...
for
...
an
...
AguaClara
...
plant.
...
This
...
entrance
...
tank
...
contains
...
riser
...
pipes
...
with
...
orifices
...
of
...
calculated
...
size
...
and
...
spacing
...
to
...
obtain
...
a
...
linear
...
relationship
...
between
...
the
...
depth
...
of
...
water
...
in
...
the
...
entrance
...
tank
...
and
...
flow
...
rate
...
of
...
water
...
through
...
the
...
plant.
...
This
...
design
...
mimics
...
the
...
shape
...
and
...
function
...
of
...
a
...
Sutro
...
Weir.
...
The
...
water
...
leaving
...
the
...
entrance
...
tank
...
is
...
mixed
...
with
...
alum,
...
a
...
coagulant,
...
en
...
route
...
to
...
the
...
flocculator.
...
When
...
alum
...
is
...
added
...
to
...
water
...
it
...
decreases
...
the
...
net
...
charge
...
on
...
suspended
...
dirt
...
particles
...
in
...
the
...
flow.
...
When
...
particles
...
collide
...
in
...
an
...
un-coagulated
...
stream
...
(one
...
not
...
treated
...
with
...
alum),
...
they
...
tend
...
to
...
repel
...
one
...
another.
...
Conversely,
...
particles
...
in
...
a
...
coagulated
...
stream
...
are
...
more
...
likely
...
to
...
actually
...
stick
...
together
...
and
...
form
...
larger
...
conglomerates.
...
These
...
larger
...
clumps
...
of
...
particles
...
are
...
referred
...
to
...
as
...
flocs.
| Wiki Markup |
|---|
\\ {float:right|border=2px solid black|width=300px} [!Ojojona Photos^0015_08_130.jpg|width=300px!|Ojojona Photos] {float} |
Alum
...
and
...
chlorine
...
are
...
dosed
...
using
...
a
...
flow
...
controller
...
(FC)
...
developed
...
by
...
AguaClara.
...
The
...
FC
...
is
...
a
...
small
...
jar
...
fitted
...
with
...
a
...
plastic
...
float
...
valve
...
on
...
the
...
inlet,
...
and
...
a
...
calculated
...
length
...
of
...
tubing
...
on
...
the
...
outlet.
...
The
...
float
...
valve
...
ensures
...
a
...
nearly
...
constant
...
head,
...
while
...
the
...
elevation
...
of
...
the
...
discharge
...
of
...
the
...
exit
...
tubing
...
determines
...
the
...
total
...
head
...
loss,
...
and
...
hence
...
flow
...
rate.
...
Plant
...
operators
...
adjust
...
the
...
alum
...
dosing
...
by
...
adjusting
...
the
...
height
...
at
...
which
...
the
...
exit
...
tubing
...
discharges
...
into
...
the
...
raw
...
water
...
stream.
...
The
...
operators
...
have
...
a
...
chart
...
that
...
relates
...
influent
...
turbidity
...
to
...
required
...
alum
...
dose,
...
and
...
required
...
alum
...
dose
...
to
...
the
...
required
...
tubing
...
exit
...
height.
...
Chlorine
...
is
...
dosed
...
similarly,
...
except
...
that
...
the
...
chlorine
...
FC
...
exit
...
tube
...
discharges
...
into
...
the
...
plant
...
exit
...
stream.
...
The
...
dose
...
delivered
...
by
...
the
...
FC
...
is
...
therefore
...
a
...
function
...
of
...
the
...
(constant)
...
head
...
in
...
the
...
bottle,
...
the
...
(constant)
...
length
...
and
...
diameter
...
of
...
the
...
outflow
...
tubing,
...
and
...
the
...
elevation
...
at
...
which
...
the
...
tubing
...
discharges.
The rapid mix through the flocculator
| Wiki Markup |
|---|
\\ h4. The rapid mix through the flocculator {float:left|border=2px solid black|width=300px} [!Tamara Report Photos^Flocculation Tank Figure 7.jpg|width=300px!|Tamara Report Photos] {float} |
Alum
...
and
...
raw
...
water
...
flow
...
through
...
a
...
short
...
series
...
of
...
pipe
...
elbows
...
acting
...
as
...
a
...
rapid
...
mix.
...
This
...
disperses
...
the
...
alum
...
throughout
...
the
...
raw
...
water
...
stream,
...
ideally
...
coating
...
a
...
significant
...
number
...
of
...
the
...
suspended
...
particles.
...
This
...
mixed
...
solution
...
then
...
enters
...
the
...
vertical
...
flow
...
hydraulic
...
flocculator.
...
The
...
vertical
...
flocculator
...
for
...
treatment
...
of
...
small
...
flow
...
rates
...
was
...
also
...
developed
...
by
...
the
...
team
...
at
...
Cornell
...
University.
...
The
...
flocculator
...
is
...
comprised
...
of
...
a
...
series
...
of
...
channels
...
with
...
alternating
...
up
...
and
...
down
...
baffles.
...
The
...
baffles
...
force
...
water
...
to
...
change
...
direction
...
through
...
an
...
amount
...
of
...
space
...
that
...
is
...
calculated
...
to
...
provide
...
target
...
mixing.
...
This
...
mixing
...
is
...
vital
...
to
...
the
...
water
...
treatment
...
process
...
because
...
it
...
is
...
the
...
engine
...
that
...
drives
...
floc
...
formation.
...
At
...
the
...
beginning
...
of
...
flocculation
...
the
...
suspended
...
particles
...
are
...
small.
...
The
...
vertical
...
flocculator
...
has
...
many
...
more
...
tight
...
turns
...
in
...
the
...
early
...
sections
...
of
...
the
...
tank
...
as
...
compared
...
with
...
the
...
later
...
sections.
...
As
...
the
...
stream
...
mixes
...
and
...
larger
...
flocs
...
form,
...
the
...
number
...
of
...
baffles
...
per
...
unit
...
length
...
of
...
the
...
tank
...
decreases
...
to
...
reduce
...
the
...
strain
...
on
...
the
...
flocs.
...
The
...
exact
...
values
...
for
...
mixing
...
parameters
...
at
...
various
...
stages
...
of
...
floc
...
formation
...
are
...
currently
...
a
...
central
...
focus
...
for
...
the
...
AguaClara
...
laboratory
...
research
...
team.
...
Earlier
...
AguaClara
...
plant
...
designs
...
employed
...
the
...
use
...
of
...
a
...
horizontal
...
flocculator
...
instead
...
of
...
the
...
vertical
...
model
...
now
...
in
...
use.
...
The
...
horizontal
...
model
...
is
...
similar
...
to
...
the
...
vertical
...
one,
...
except
...
that
...
the
...
stream
...
is
...
forced
...
to
...
side-wind
...
from
...
left
...
to
...
right
...
through
...
the
...
channels,
...
instead
...
of
...
up
...
to
...
down.
...
The
...
vertical
...
flocculator
...
has
...
a
...
smaller
...
footprint
...
than
...
its
...
horizontal
...
counterpart,
...
which
...
decreases
...
the
...
overall
...
cost
...
of
...
construction.
...
The
...
vertical
...
model
...
also
...
is
...
less
...
prone
...
to
...
premature
...
sedimentation
...
throughout
...
the
...
tank,
...
which
...
is
...
another
...
main
...
reason
...
why
...
the
...
team
...
has
...
shifted
...
focus
...
to
...
vertical
...
flocculation.
...
The
...
sedimentation
...
tanks
...
to
...
the customers
| Wiki Markup |
|---|
customers {float:right|border=2px solid black|width=300px} [!Tamara Report Photos^Flocculation to Sedimentation Channel Figure 9.jpg|width=300px!|Tamara Report Photos] {float} |
The
...
stream
...
leaves
...
the
...
flocculator
...
and
...
travels
...
to
...
the
...
sedimentation
...
tanks
...
via
...
a
...
channel.
...
The
...
tanks
...
have
...
bottom-level
...
entrance
...
manifolds
...
to
...
distribute
...
water
...
evenly
...
across
...
the
...
floor
...
of
...
each
...
tank,
...
and
...
an
...
effluent
...
launder
...
pipe
...
collects
...
water
...
from
...
the
...
top
...
of
...
each
...
tank.
...
Tanks
...
are
...
fitted
...
with
...
arrays
...
of
...
lamella
...
that
...
are
...
angled
...
60º
...
from
...
the
...
tank
...
floor.
...
The
...
heavy
...
flocs
...
settle
...
out
...
of
...
the
...
slowly
...
rising
...
water
...
and
...
onto
...
the
...
lamella.
...
The
...
size
...
of
...
the
...
tanks
...
and
...
the
...
positioning
...
of
...
the
...
lamella
...
are
...
engineered
...
to
...
allow
...
the
...
water
...
to
...
rise
...
up
...
through
...
the
...
tank
...
at
...
a
...
slower
...
speed
...
than
...
the
...
flocs
...
take
...
to
...
fall
...
out
...
onto
...
the
...
lamella.
...
Sludge,
...
made
...
up
...
of
...
settled-out
...
flocs,
...
collects
...
at
...
the
...
bottom
...
of
...
the
...
sedimentation
...
tanks
...
and
...
can
...
create
...
a
...
diffuse
...
filter
...
for
...
incoming
...
water.
...
Having
...
some
...
degree
...
of
...
sludge
...
build-up
...
is
...
therefore
...
desirable,
...
but
...
excess
...
sludge
...
will
...
begin
...
to
...
rise
...
through
...
the
...
tank
...
if
...
it
...
builds
...
up
...
too
...
much.
...
The
...
AguaClara
...
team
...
has
...
recently
...
begun
...
to
...
design
...
weirs
...
into
...
the
...
sedimentation
...
tanks
...
to
...
control
...
sludge
...
levels
...
to
...
create
...
a
...
beneficial
...
sludge
...
blanket.
...
In
...
earlier
...
designs
...
plant
...
operators
...
isolated
...
each
...
sedimentation
...
tank
...
and
...
opened
...
a
...
bottom
...
drain
...
to
...
wash
...
the
...
sludge
...
out.
...
Current
...
designs
...
incorporate
...
a
...
system
...
of
...
sludge
...
hoppers
...
that
...
remove
...
the
...
sludge
...
only
...
to
...
a
...
specific
...
level
...
in
...
the
...
tank,
...
leaving
...
some
...
to
...
act
...
as
...
a
...
filter.
...
Most
...
of
...
the
...
initial
...
turbidity
...
is
...
removed
...
from
...
the
...
water
...
by
...
the
...
time
...
it
...
exits
...
the
...
sedimentation
...
tanks
...
either
...
way,
...
but
...
the
...
sludge
...
blanket
...
filtering
...
effect
...
may
...
help
...
us
...
achieve
...
even
...
better
...
standards
...
for
...
effluent
...
water.
...
From
...
the
...
launder
...
at
...
the
...
top
...
of
...
the
...
sedimentation
...
tanks,
...
clear
...
water
...
flows
...
to
...
a
...
distribution
...
tank.
...
Chlorine
...
is
...
dripped
...
into
...
the
...
stream
...
of
...
water
...
entering
...
the
...
distribution
...
tank
...
to
...
kill
...
any
...
bacteria
...
that
...
weren't
...
eliminated
...
by
...
removing
...
sediment.
...
The
...
chlorine
...
is
...
dosed
...
using
...
the
...
same
...
type
...
of
...
flow
...
controller
...
used
...
for
...
alum.
...
Clean,
...
disinfected
...
water
...
then
...
flows
...
from
...
the
...
distribution
...
tank
...
into
...
people's
...
homes
...
along
...
a
...
series
...
of
...
municipal
...
pipes.
...
The
...
Case
...
for
...
Treatment
...
Before
...
Chlorination
...
Influent
...
water
...
straight
...
from
...
the
...
source
...
contains
...
dirt,
...
organics,
...
and
...
potential
...
pathogens.
...
Although
...
chlorine
...
is
...
used
...
as
...
a
...
broad-spectrum
...
disinfectant
...
worldwide,
...
it
...
is
...
not
...
necessarily
...
an
...
easy
...
solution.
...
Chlorine
...
reacts
...
with
...
organics
...
present
...
in
...
the
...
water,
...
forming
...
carcinogenic
...
compounds.
...
This
...
has
...
the
...
dual
...
effect
...
of
...
not
...
achieving
...
disinfection
...
because
...
the
...
chlorine
...
is
...
"used
...
up"
...
on
...
the
...
dead
...
matter,
...
while
...
also
...
creating
...
a
...
new
...
health
...
hazard.
...
Flocculation
...
is
...
essentially
...
the
...
process
...
of
...
sticking
...
solids
...
in
...
raw
...
water
...
together,
...
while
...
sedimentation
...
is
...
the
...
process
...
of
...
letting
...
those
...
heavy
...
solids
...
sink
...
out.
...
The
...
resulting
...
water
...
is
...
clear
...
of
...
most
...
solids,
...
which
...
allows
...
us
...
to
...
add
...
chlorine
...
to
...
kill
...
remaining
...
pathogens
...
without
...
producing
...
excessive
...
byproducts.
...
The
...
Social
...
and
...
Cultural Side
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Social
...
sustainability
...
is
...
of
...
key
...
importance
...
to
...
the
...
AguaClara
...
team.
...
The
...
first
...
concern
...
for
...
plant
...
design
...
features
...
is
...
that
...
they
...
be
...
practical
...
for
...
the
...
communities
...
using
...
them.
...
All
...
AguaClara
...
plants
...
are
...
built
...
by
...
locals
...
through
...
construction
...
projects
...
supervised
...
by
...
the
...
Honduran
...
NGO
...
Agua
...
Para
...
el
...
Pueblo
...
(APP).
...
Two
...
Cornell
...
graduates
...
apply
...
to
...
spend
...
a
...
year
...
as
...
employees
...
of
...
APP
...
while
...
assisting
...
with
...
plant
...
operator
...
training
...
and
...
data
...
collection.
...
Groups
...
from
...
the
...
Cornell
...
team
...
visit
...
the
...
sites
...
of
...
AguaClara
...
plants
...
several
...
times
...
each
...
year,
...
interviewing
...
customers
...
and
...
plant
...
operators
...
to
...
gain
...
an
...
understanding
...
of
...
how
...
to
...
better
...
suit
...
our
...
research
...
and
...
design
...
to
...
the
...
local
...
needs.
...