A B ST R A C T
V A N
E
SS A
R A
N H
A
D A
P I
N
T
O
J
O
R
G
E
P
E
R
E I R
A
.U
s e of
aC
h lo r a
m i
n
at
ed
D
ri
nk i
n
g
W
at
e rS
y
st
em
t
oD
e v elo
p A
c c u r at
eP
r ed ic
t
iv e
P
at t
e r n s of E
xp
o su
r et
oD i
si
n
f
e ct
io
n
-B
y
-Pr o
d
u
ct
sb
y
C
o n su
m
e r s,(
un
d
e rt
h
ed i
r e ct
i
o n of D
r.H O
WA R D S
.WE I N B E R G
)
I
n a n at
t
em p
t t
op
r o vi d
em
o r e a c c u ra
t
e e xp
o s u r el
e v el
st
od i
si
nfe c
t
io n
b y
-p
r od
u
ct
s(
D
B P
s)
i
n
d
rin
k i
n
g
w
at
e rb
y
c o n s um
e r s,t
h
el
e v els
of
t
rih
alo
m
eth
a n e s(
T H
M
s)
,h
alo a c e
t
i
c a ci d
s(
H A A
s)
, an
d
t o
t
al
o rg
an
i
ch
alo
g
e n(
T O X
)
w
e r em
e
a s u r ed
a nd
c o r r el
a
t
ed
b
et
w
e e nt
h
ep
oin
t
of
e nt
ry
(
P O E
)
fr
om
an
o z o n e-c
h l
o r am
in a
t
io n
p l
a nt
a nd
t
h
o s em
e
a s u re
d
th
ro
ug
h
ou
t t
h
ed i
st
ri b
ut
io
n
sy
st
em
(
D S
)
.S
am
p
le s
c ol l
e ct
ed
e v e ry
f
o u rh
o u r sd
u
rin
g
fi
v e c o n s e c ut
iv e
da
y
s sh
ow
ed
t
h
at
t
em
p
o r al
v a ri
ab i l i
t
y i
nt
h
eD B
P
le v e
ls
at
t
h
eP O E
c an
be
e xp
e ct
ed
.H
ow
e v e r ,th i
sv a r
ia
b i l i
t
y
ap
p
e a r ed
t
obe
d
am
p
e n ed i
nth
ed i
st
ri b
ut
i
o n sy
st
em w i
t
h
t
h
e a v e r ag
ele v e
ls o
f
D B
P
sm
e a s u r ed
o v e r a n e xt
e nd
ed
p
e ri
od
v e ry
si m i la r
at
al l
s am
p
l
ep
oin
t
s.A
si
n
g
le
g
r ab
s a
m p l
e c ol l
e ct
ed fr
om
a r ep
r e s e nt
at
i
v eD S
p
oi
n
t
w
o ul d
t
h
e r ef
o r eb
e ag
o
od i
n
d i
c at
io
n
of
D B P
e xp
o s u r et
o c o n s um
e r s of
t
h
at
dr
i
nk i
n
g w
at
e r .T h i
s st
ud
y
w i l l d
em
o n st
r at
eh
ow
am
o nit
o ri
n
g p
r og
r am
w
a s e v ol
v ed
th
at p
r o vi d
e sf
o r a r e a s o n ab le
e xp
o s u r ele v e
l
of D B P
st
o c o n s um
e r s of d
rin
k i
n
g
w
at
e r u si
n
g
aT A B L E O F
C O
N T E N T S
I
.O b
j
e ct
i
v e sI I
.B
a ck g
r o un
d
2
I
I
.A
.D i
sin
f
e ct
io n
of D
rin
k i
n
g
W
at
e r2
I I
.A
.1
.D i
sin
f
e ct
io n
u sin
g F
re
eC h l
o rin
e2
I L A
.2
.D i
sin
f
e ct
io n
u si
ng
C
om b i
n ed C h l
o ri
n e3
I I
.A
.3
.M
ic r o
b io c
i d
al E f f
i c a cy
of Fr e e
C h l
o ri
n
e a nd C h l
o r am
i
n
es
6
I I
.A
.4
.F
a ct
o r st
h
at
I
nf lu
e n c eM
ic r o
b i
al
I
n a ct
iv a
t
io
n
b
y
F
r e eC h l
o ri
n e a nd
M
o n o ch lo r a
m i
n
e s7
I I
.A
.5
.M
e ch
a nis
m
so
f
M
i
c r ob i
al I
n a ct
iv a
t
i
o nb
y
F
r e eC h l
o rin e a n
d C h l
o r am i
n
e s ....8
I I
.A
.6
.O
th
e rD i
sm fe c
t
an t
s u s ed i
n
D
rin
k i
n
g
W
at
e r9
I I
.B
.D i
sin
f
e ct
io n
B
y
-P
r o
d
u ct
s10
I I
.B
.l
.N
at
u r al O
rg
a ni
cM
at
t
e r10
I I
.B
.
2
.D i
si
n
f
e ct
i
o nB
y
-P
r od
u c
t
sP
r op
e rt
i
e s1 1
I I
.B
.3
.M
e ch
a ni
sm
of D i
si
n
f
e ct
i
o nB y
-
P
r od
uc t
sF
o rm
at
i
o n15
I I
.B
.4
.H
e al
t
h E f f
e ct
s16
I I
.B
.4
.a
.L it
e r atu r e
R
e vi
ew
o nS
p
on
t
a n e o u sA b
o rti
o nE
xp
o
s u r eA
s s e s sm
en
t
17
I I
.B
.5
.R
eg
u
la
t
o ry R
eq
uir e
m
en t
s18
I
I
.B
.6
.D B
P
Pr o
d
u ct
io n
b
y
D i f f
e r e nt
D i
si
nf
e ct
an
t
s19
I I
.B
.7
.F
a ct
o r st
h
at
I
n
f lu e n c e
D B P
E
xp
o s u r eL
e v el
s2 0
I I
.B
.7
.a.R
aw
W
at
e rC h
a r a ct
e ri
st
i
c s2 0
I I
.B
.7
.b
.W
at
e rT
r e at
m
e nt
2 1
I I
.B
.7
.C.D i
str
i b
ut
i
o nS
y
st
em
2 2
I I I
.E
xp
e
ri
m
e nt
al P
r o c ed
u r e s an
d
M
et
ho
d
s2 6
I I I
.A
.E
xp
e rim
e nt
al
P
r o c ed
u r e s2 6
I I I
.A
.1.
D
e s c ri
p
t
io
n
of
t
h
eSt
ud
y
Pr o
j
e ct
2 6
I I
I
.A
.l
.a.D
e s c ri
p t
io n
of
t
h
eT
r e at
m
e nt
P
la
n
t
2
7
I I I
.A
.l
.b
.D i
st
ri b
ut
i
o nSy
st
e
m
D
es
c rip
t
io n
2 8
I
I
I
.A
.2
.H
ol d i
n
g T i
m
eS
t
ud
y
:E
ff
e ct
s of C h l
o ra
m
in
at
io n
on
T H
M
a nd H A A L
e
v el
so v e r
T i m
e3 2
I I
I
.A
.3
.D B
P
V
a ri
ab i l i
t
y
at t
h
eP
oin t
of E
ntr
y
t
ot
h
eD
is
t
ri b
ut
i
o nS
y
st
em
3 3
I I I
.A
.4
.T
em
p
o r al
an
d S
p
at
ia
l V
a ri
ab i l i
t
y i
n
D B P L
e v el
s3 4
i n
.A
.5
.W
at
e rQ
u al i
t
y
M
od
el m
g
3 7
I I I
.A
.6
.W
e ek l
y
E
xp
o su
r et
oD
B
P
s3 8
I
I
L A
.7
.D B P E
xp
o s u r eD
u rin
g P
e ri
od
of F
r e eC h lo r
in
e3 8
I
I
I
.A
.8
.A
n al y
si
s of P
o s si b l
eC
on
f
o u nd in
g
F
a ct
o r sin
E
xp
o s u r eC h
a r a ct
e riz a
t
i
o n ...4 1
I I I
.B
.E
xp
e rim
e nt
al
M
et
h
od
s4 2
I I
I
.B
.1
.Sa
m
p
l
eC
oll
ec t
io
n
4 2
I I
I
.B
.1
.a.S
am
p
le
Co
l l
e ct
io n
P
r o c ed
u r e4 3
I I I
.B
.l
.b
.D
e v elo
p
m
e nt
of
aC
om p
o si
t
i
n
g T
e ch
ni q
u e4 3
I I I
.B
.2
.A
n al
y t
i
c al
M
et
h
od
s
4 4
I I I
.B
.2
.a.T
ri h
alo
m
et
h
a n e s4 4
I I
I
.B
.2
.b
.H
al
o a c et
ic
A
ci d
s4 6
I I
I
.B
.2
.C.T
ot
al O
rg
a ni
cH
al i d
e4 8
I I I
.B
.2
.d
.T
ot
al O
rg
a ni
cB
ro
m i d
e4 9
I
V
.R
e su
l
t
s a nd D i
s cu
s si
o n5 1
I
V
.A
.E f f
e ct
s of C h l
o r am i
n
at
i
o n o nT H
M
an
d H A A
L
e v el
s5 1
I
V
.A
.1
.B
ot t
l
eS
t
o r ag
eT
e st
5 1
I V
.A
.2
.F
i
el d
M
o ni
t
o ri
n
g
T
e st
s5
3
I
V
.B
.D B
P V
a ri
ab i l i
t y
a t
t
h
eP
oi
n
t
of
E
nt
ry
t
ot
h
eD i
st
ri b
u t
i
o nS
y
st
em
(
T
em
p
o r al
E
f fe
ct
s)
5
5
I V
.B
.1
.D
e v el
op
m
e nt
of
aC
om
p
o si
t
i
n
g
T
e ch
n
i q
u
e5 9
I V
.C
.T
em
p
o r al
a nd
Sp
at
i
al V
a ri
ab i l i
t
y
i
n
D
B
P
L
e v el
s6
0
I
V
.D
.W
at
e rQ
u aU
t y
M
od
el i
n
g
6
7
I
V
.E
.W
e ek l
y
E
xp
o s u r et
oD
B P
7
1
I
V
.F
.D
B P E
xp
o s u r ei
n
aF
r e eC h l
o ri
n eS
y
st
em
7
5
I V
.F
.L
C
om p
a ri
s o n of D B P F
o rm
at
i
on
i
n
aC h l
o ri
n at
ed
an
d C h l
o
r am i
n
at
ed
S
y
st
em
8
1
I V
.G
.A
n al
y
si
s of p
o s si b l
e c on
f
o u nd i
ng
f
a ct
o r si
ne
xp
o s u r e ch
a r a ct
e ri
z at
i
o n8 3
I V
.G
.l
.E ff
e ct
of
t
i
m
e of
s am
p
l
e c ol l
e ct
i
o n8 3
I V
.G
.2
.E f fe
ct
of b
oi l i
n
g
o r r efr i g
e ra
t
i
n
g
w
at
e r8 3
V
.C
on
cl
u
si
on
s8 5
V I
.R
e c om
m
en
d
at
i
o n sf
o rE
xp
osu r e
A
s s es
sm
e nt
S
tu
d i
e s8 9
V I I
.R
ef
e r en
ce
s9 1
A p
p
e nd i
xA
-
T
H
M
S
t
a nd
a rd O
p
e r at
i
on
P
r o c ed
u r e9 9
A
p p
en
d i
xB
-
H A A S
t
a
nd
a rd O p
e r at
i
on
P
r o c ed
u r e10 8
A p p
e nd i
xC
-
T O X S
t
a nd
a rd O
p
e r at
i
o nP
r o c ed
u
r e1 14
A
p
p
e nd i
xD
-
T O B
rS
t
a n
d
a rd O p
e r at
i
o nP
r o ce
d
u r e12 9
A p
p
e nd i
xE
-
F
r ee
an
d
T
ot
al C h l
o ri
n eD
et
e rm i
n
at
i
o n14 8
L I
ST
O
F F
I G
U
R E S
F
i
g
u r el
:T H
M
and
H A
A
f
o rm
at
i
on15
F i g
u r e2
:C
o n v e nti
o n al
dr
in
k in
g
w
at
e r tr e atm
ent p
r o c e s sw it
h
d i
f f
e r e nt p
oin
t
s of
add i
ti
o n of
fi
nal
d
i
sin
f
e cta n
t
s2 2
F
i
g
u r e3:
T
r e at m
e nt p
r o c e s s em
p l
oy
ed in
th
e st
ud y
-sy
ste
m
. .2 7
F
i
g
u r e4
:D i
strib
ut i
o nS y
stemM
ap
3 0
F
i
g
u r e5
:L
o c at i
o n of t
h
ew
at
e rt
r e atm
e nt p
l
a nt
r ela
t iv e
to
t
h
ef
o u rd
i
st
ri b
uti
o n sy
ste
m
lo c a
t i
o n s s am
p l
ed
(
D S I
,D S I I
,D S I I I
-
A
a nd
D S I I I
-B
)
in
t h
e thr e e s a
m p li
ng
e v ent
s3
6
F ig
u r e6
:A
r cV i
ew m
ap w i t h t h
e10
D
S
s am
p li
ng p
oin
ts
ch
o s en,t h
ew
ate r tr e atm
e nt
and th
el
o c al i
z atio n
of
t h
e s ub
j
e ct
s en r ol l
ed i
nth
e stu
d y
4 0
F
i
g
u r e?
:S
um m
a ry
of T H
M
a n al
y
sisp
roc ed
u r e4 5
F
i
g
u r e8:
Su
m m
a ry
of H A A
a n al y
si
sp
r o c ed
u r e4
7
F
i
g
u r e9
:S
um
m
a ry
of
T O X
a n al y
si
sp
roc ed
ur e4 8
F ig
u r e10
:S
um m
ary
of
T O B
r a n aly
si
sp
r o c edu r e
4 9
F i
g
u r e1
1:
T H
M
c o n c e nt
r ati
o n s a safu n c
tio
n of
e xte
nd
ed
c o nta c
t t
im
ew it
h
ch l
o r am
in
e s5
1
F ig
u r e12
:H A
A
c o n c en tr at i
o n s a s afi
m
ct i
o n of
e xt
e nd
ed
c onta c
t
t im
ew it
h
ch l
o r am
in
e5 3
F
ig
ur e1 3
:Co n c e
ntr a
t
i
on s of
t
ot
al
t
rih
al
om
et h
ane sm
ea s u r ed
in
th
ed
i
str
i b
ut
i
o n sy
stem d
uri
ng t
he
y
e a r2 0 0 0
5 4
F
i g
u r e1
4
:T H
M
vari
ab i l i
t y
at t h
ep
oi
nt
of
e ntr
y t
oth
ed i
stri b
uti
on sy
stem
5 5
F ig
u r e16
:C
om
pa ris o n
of
total
trih
al
om
eth
ane c o n c e ntr atio n
sle
a vin
g
th
e tr eatme n
t pla
n t( W
T P
)
a nd in
th
ed i
str
i
bu
t
i
on sy
stem
(
D S I
)
6 1
F
i
g
u r e17
:C
om
p
a ris o n
of t
ot
al t
rih
al
om
et h
a n e c o n c e ntr a
ti
o n sle a v
in
g t
h
etr
e at
me n
t p l
ant
(
W
T P
)
and in
t h
ed i
str
ib
ut
i
o n sy
ste
m
(
D S I I
)
6 2
F i g
u r el 8
:T T H
M
a nd
T O X
at D S I I I
-A
6 5
F i g
u r e19
:C
om
p
a ri
s onb
etw
e e n th
eT T H
M
c onc e ntr ati
o n s ob
tain
ed
att h
ew
ate rtr e a
tm
e ntp l
a nt(W
T P
)
and
tw
od i
str
i b
ut
i
o n sy
stem
p
oin
t
s(
D S I I I
-A
a nd
D
Si
n
-B
)
6 5
F
i
g
u r e2 0
:Co
m
p
a ri
sonb
et w
e e nth
e e xp
e rim
e nt
al
(
ob
s e r v ed
)
and
t h
em
ode
l
(
c om
p
ute
d
)
T T H
M
c o n c e n
tr a
t i
o n s ob t
ain
ed i
nD S I f
o rF
eb
r u a ry 6 t
o9
of 2 0 0 1
6 8
F i g
u r e2 1
:C
om
p
a ri
s o nb
etw
e e nth
e e xp
e rim
e nta
l
(
ob
s e r v ed
)
and fl
i em
od
el
(
c om
p
uted
)
T T H
M
r e s ult
so
b t
ain
ed i
nD S I I fo r
F
ebr u a r
y 17 t
o2 0
of 2 0 0 1
6 9
F
i
g
u r e2 2
:C
om
p
a ri
s o nb
etw
e e nth
e e xp
e rim
enta
l
(
obs e r v e
d
)
a nd
th
em
od
el
(
com
p
ut
ed
)
T T H
M
r esults
o
b
ta
in
ed
in
D S I I I
-A fo r
A
ug
u st 14 t
o17
of 2
0
0 1
7 1
F
i
g
u r e2
3
:T H
M
r e s ults
of
w
e ek l
y
s am
p l
e s col l
e ct
ed
at D S I I I
-A
7 2
F i g
u r e2
4
:R
ela
t iv
ep
r op
o rt i
on of
in
di
vid
u al
T H
M
sp
e cie s c o n
tri b
ut i
ont
oT T H
M
at D S I I I
-A
7 3
F
i
g
u r e2 5
:T T H
M
,T
H
A A
and T O X
r e s ul t
s of
w
e ek l y
s am
p l
e s c oll
e cted
in
D S I I I
-
A
7 4
F i g
u r e2 6
:C
or r el
ati
o nb
etw
eent h
eT O X
a nd
T H
M
c o nc e ntr a
t
i
o n s obt
ai
ned
w
e ek
l
y
7
5
F i
g
u r e2
7
:C
om
p
a ri
s onbe
t w
e e nth
eT T
H
M
a nd
fr
ee ch l
orin
e resi
du a
l
s re sul
ts
obta
in
ed in
e a ch w
eek
7
6
F i g
u re2 8
:C
om
p
a ri
s o nb
et w
e e nth
eT T H
M
and T H A A
r e s ul t
s obt
ain e
d
in
e a ch w
e ek
7 8
F
i
g
u r e2 9
:C
om
p
ari
sra
ib
et w
ee nt h
eT O X
a nd
th
eT T H
M
a nd
T H A
A
r esult
s ob
ta
in e
d in
e a ch w
e ek
7
9
F i
g
u r e3 0
:C
om
p
a ris o n
be
t w
e e nt
he
T T H
M
,T
H A
A
and
u nkn o
w
nO X
le v e
l
sin
ch lo r
in
ate
d
and
c
h
l
o r am
in
at
ed
w
ate r s
8 1
F
i g
u r e3
1
:C
om
p
ari
s onb
etw
eenth
eT T H
M
a nd
T H A
A l
e vel
sin
t
he
p
oin
t
of
ent
ry t
oth
ed i
st
rib
ut
io
nL I
ST
O F
T A B L E
S
T
ab
l
e1:
C
om
p
ari
s o n of th
em
i
c rob i
o ci d
al
ef fi
ci
e n cy
of
fr
e e ch l
ori
n ew i t
h
c om b i
ned
ch lori
ne at 5
' 'C
and
p H
v a
l
ues r a ng
in
g
fr o
m
6 t
o9
(
9 9
% i
n a ct i
v at
i
on)
6
T
ab
l
e2
:Pr
op
ert
ie s
of
T H
M
s12
T
ab
l
e3
:Pr o
p
e rt i
e s of
H A A
s1
3
T
ab
l
e4
:E
st im
a ted
r ete n
t i
o nt im
ein
s am
p l i
ng l
o c at
i
ons3 1
T
ab
l
e5
:St
or ag
et
ank
sl
o cat io n
, stor ag
e and
ov e rfl
ow
v olu
m
es3 2
T
ab l
e6
:D
at
e s a nd
s am
p l i
ng l
o c ati
o n s u s ed
t
o cha r a c
te r
iz e
t h
ete
m
p
o r al
and
sp
atia
l
v a ria
b
i li
t y i
nt h
eD B P
le v e
l
s3 5
T
ab l
e7
:T H
M
sam p l
e c ol l
e ct i
o np
e ri
od
u s ed
as u ip
ut f
o rE P
A
N E T
si
m
ul
ati
on s3
8
T
ab
l
e8
;R
et
ent
i
o n ti
m
e s at th
e s am
p l i
ng p
oin
t
s4 1
T
ab l
e9
:T T H
M
,T H A A
a nd
T O
X
v ari
ab i
Ut y
at t
he
p
oi
nt
of
ent
ry t
ot h
ed is
tri b
ut
i
o n sy
stem
5 7
T
ab l
e10
:C
al
c ula
ti
o n of t h
eU
nk
n ow
nO
rg
a ni
ch
al id
e(
O X
)
c o n c e nt
r at i
on5 8
T
ab l
e1 1
:R
e c o v e ri
e s obt
ai
ned
u si
ng
a c om
p
osi tem
et h
od
5 9
T
ab l
e12
:D
ai
l y
a v e r ag
eT T H
M
and T H A
A
c o n c en tr at i
o n sm
e a s u r ed
at
th
etr e a
t m
e nt p l
a nt
(
W
T P
)
and
at
D
SI I
6 3
T
ab
l
e13
:T T H
M
d
at
a u s ed
a sin
p
ut fo r
sim
ula
t i
o n s at D S I
6 7
T
ab l
e14
:T T
H
M
da
t
a u s ed
asi
np
ut
fo r
sim
ula
t
i
ons at D S I I
6
9
T
ab l
e15
:T T H
M
d
at
a u s ed
asi
np
ut
fo r
sim
ula
t
i
o n s at D S I I I
-A
7 0
T
ab l
e16
:T T H
M
a nd T
H A
A
r e s ul
t
sdu r
in
g p
e ri
od
of
ch l
o rin a
ti
on7 7
A C
K
N
O
W
L E D
G
E
M
E N T S
F i
r st
an
d f
o r em
o st
,I w
o ul d l i k
et
oth
a nk
D
r .H
ow
a rd S
.W
ei
n
b
e rg
f
o rh i
sin
v al
ua
b l
e a nd
c o nt
in
u o u sg
ui d
an
c e a nd
en
c o u r ag
em
e nt
.I
am
al
s od
e ep
l y
g
r at
ef
ul
t
oD
r.Ph i l l i p C
.Sin
g
e rf
o rh i
s e xp
e rt
i
s e.T h i
s r e se
a r ch b
e n ef i
t
ed
en
o rm
o u sl y fr
om h i
si
n
p
ut
.I
a
m
al
s oin
d
eb
t
t
oD
r .M
i
ch
a el D
.A i
tk
e nf
o rb
ein
g
a r e ad
e r of
t
h i
st
h
e si
s an
d f
o rp
ro
vi d i
ng
im
p
ort
an
t
a c ad
em i
c
g
ui d
an
c ed
u ri
n
g t
h
e s el
a st t
w
oy
e a rs
.I w
o ul d
al
s ol i k
et
ot
h
a nk C
a r ri
eD
el
c om
y
n ,F
r ed
e ri
q
u eB
l in
a nd D
a ni
el R
ad i l
of f
f
o rth
ei
rh
el
p
i
n
s am p l
e a n aly
s e s,L
a r ry
M
cM
i l l
a nf
o r cl
a ri f i
c at
i
o n s ab
o ut
w
at
e rt
r e at
m
en
t
p
ro
c e s s e s an
d
M
a rt
es
aW
eb b f
o rh
el
p
i
ng w i
th
s am
p
l
e c ol l
e ct
i
o n,D
r.D
a
vi d S
a vi
t
z a nd
C h
ri
st
i
n aM
ak
a r u sh k
af
o rt
h
ei
r v al
u
ab l
ei
n
p
ut
i
n
t
h i
s r e s e a r ch
, an
d
m
y
l
ab
o r at
o ry
r e s e a r c
h
g
r o up
an
d
offi
c em
at
e sf
o rth
ei
r s up
p
ort
an
d fr i
e nd
sh i
p
d
u rin
g t
h
e s ey
e a r s.F i
n
an
ci
al
s up
p
ort
fr
om
th
eA
m
e ri
c a nW
at
e rW
o rk
sA
s s o ci
at
i
on
R
e s e a r ch
F
o vm
d
a t
i
on
,p
r oj
e ct
2 5 7 9
,i
sg
r at
ef i
il l
y
a ck
n
ow l
ed g
ed
.A
sf
o rm
y
d
e a rf
am i l
y
an
d
P
ort
u
g
u e s efr i
e nd
s"
m
uit
o ob
ri g
ad
o , o v o ss
o am
o rp
e rm i
t
i
u-m
e ul
t
r aI
.O
B J E C T I V E S
T
h
i
s st
ud
y
i
sp
a rt
of
afi
v e-y
e a rp
r oj
e ct
b
ein
g
c o nd
u ct
ed b
y
at
e am
sp
e ci
ali
zi
n
g i
n
e
p i d
em i
o
lo
g y
,w
at
e rc
h
em i
st
ry
an
d
e ng i
n e e
rin
g
, st
at
i
st
ic s
, a nd
ob
st
et
ric s
t
od
et
e
rm
in
ew he
t
h
e rt
h
e o c c u r r en c
e of
sp
o nt
a n e o u s ab
o rt
io n
m i
g
ht
b
e r el
at
ed
t
ot
h
ep
r e s en
c e of
d i
si
n
f
e ct
io n
b
y
-p
r od
u ct
s(
D
B F
s)
in
dr
in
k i
ng w
at
e r.Pr e v
i
o u s ep i d
em io
l
og
ic a
l
st
ud i
e sf
o un
d
p
o si
t
iv e c o r r e
la
t
io n s
b
et
w
e e nth
ep
r e s e n c eo
f D
B F
sin
d
rin
k i
n
g
w
ate r
a nd
sp
o nt
an
e o u s abo
rt
io n
.H
ow
e v e r,t
h
e s e stu
d i
e s u s ed g
r o s se s
t
im
ate s
of
e xp
o s u r e, n ot
c o n si d
e ri
ng
t
h
eD
B F
sp
at
ia
l
a nd
t
em
p
o r al
v a ria
b i l i
t y
, a nd
t
h
e r ef
o r eh
a v e a s e ri
o u s ri
sk
of
m
i
s cl
a s si fi
c at
io n
of
e xp
o s xi r e a s s o cia
t
ed
.T h
e ob
j
e ct
i
v e s of
t
h i
s a sp
e ct
of
t
h
e st
ud
y
a r et
op
r o vi d
e ap p
r o a ch
e st
o ac
c u r at
el
y
a s s e s s e x
p
o s u r et
oD
B
F
si
n
d
ri
nk in
g
w
at
e r,m
e a s u r ed in
t
e rm
s of
t
ri h
al
om
et
h
a n e(
T
H
M )
,ha
lo a c e
t
i
c a ci d
(
H A A
)
, an
d
to
t
al
o rg
a
nic
h
al
og
e n(
T O X
)
c o n c en
tr a
t
io n s
.T
o
m
e et t
h
e s e ob
j
e ct
i
v e s,t
h is
st
u
d
y
f
o c u s ed
o n a nin
t
e n si
v e e v al
u at
i
o n of
t
h
eD B
F
c o n c e nt
r at
i
o n sin
t
h
ef in
i
sh
ed w
at
e r a nd d i
st
ri b
ut
i
on
sy
ste
m
at
aw
at
e rtr e a
t
m
e nt
p l
an
t
u si
n
g
ch lo r a
m i
n a
t
io
n
f
o rf m
al d i
si
n
f
e ct
i
o n .Sa
m
p l
e c ol l
e ct
i
o n ap p
r o a ch
e sw
e r es
t
ud i
ed
i
n
clu
d i
n
g
t
h
ed
e v elo
p
m
en t
of
a s am
p
l i
n
g
st
r at
eg y
t
od
et
e rm
i
n
et
h
em
o st
r e
p
r e s e nt
ati
v ed i
str
i b
ut
i
o n sy
st
em
lo c a
t
io n s
fr
om
w h i
ch
s am
p
le s
sh
o uld b
e c ol l
e ct
ed
to
I I
.B A C
K
G R O
U
N
D
n
.A
.D
i s i n f e c t i o n o f
D
r i n
k
i n g
Wa t e r
D i
sin
fe c
t
io n
of dr
in
k i
ng
w
at
e r u si
n
g fr
e e ch l
o rin
e a nd
ch lo r a
m i
n e si
sw i d
el
y
u
s ed
a n
d h
a s s a v ed m i l l i
o n s of l iv e s
fr
om
w
at
e rb
om
ed i
s e a s e s.I I
.A
.l
.D i
si
nf
e ct i
o n u si
n gF
r e eC
h l
o ri
n eC h lo
ri
n
e c an
b
eu
s ed in
w
at
e rt
r e at
m
en
t
a s a n o xi d iz
in
g
ag
e nt
(
m
ain
l y
u s ed fo r
t
a st
e, od
o r a nd
c olo r
c o nt
r ol
a nd
o xi d
at
i
o n of ir o
n
a nd m
a ng
a n e s e of
g
ro
un
dw
at
e rs u
pp U
e s)
an
d
a s ad i
sin
f
e ct
a nt
(
f
o ri
n a
ct
i
v at
i
o n of m i
c ro
o rg
an
is
m
s)
.T h
e ad
v a nt
ag
e s of i
t
su s e
i
n clu
d
et
h
e e a sy p
r od
u ct
io n
, c o nt
r ol
, st
o r ag
e,t
r a n sp
o rt
a nd
ap p
l i
c at
io n
,lo
w
c o st
, an
d
h
a vi
ng
a v e ry
b
r o ad
r an
g
e of
ef f
e ct
i
v e n e s si
n
clu
d i
n
g
t
h
e
a e sth
et
ic
q
u al i
t
y
c on
t
r ol
,r e
m
o v al
of i
r o n ,m
an
g
a n e s e a nd h
y
d
r og
e n s ul
f i d
e, st
e ri l i
z at
io n
of
m
ai
n s a nd
st
o r ag
et
a nk
s, r e st
o r ati
on
an
d
p
r e s e r v at
io
n
of
p
i p
e c ap
a ci
t
y
an
d
m
ain
t
en
an
c e of
ap
e r si
st
e nt
st
a
b le
r e s
i d
u al in
t
h
ed i
st
ri b
ut
i
on
sy
st
em
.T h
ed i
sin
fe c
t
io n
of d
ri
nk i
n
g w
at
e r u si
ng
ch l
o
ri
n
ec
an
b
e
ac
h ie
ve
d b
y
a
p p l
y
in
g i
t
a s a c o
m
p
r e s s ed g
a s un
d
e rp
r e s s u r e o rin
l i
q
ui d
s ol
ut
i
o n s(
s od iu
m
h
y
p
o ch lo r
it
e o rc a
lc
i
um h
y p
o ch lo r
i
t
e)
.T h
e c o nd
e n s at
i
o no
f m
o
le c u
la r
ch l
o rin
eg
a si
n
t
o al i q
ui d
c a nbe
a ch ie v e
d w he n
t
h
eg
a si
s s ub
j
e ct t
op
r e s s u r e sin
e x c es
s of i
t
s va
p
o rp
r e s s u r ew i
th
t
h
e r ele a s e o
f h
e at
a nd
ad
e c r e a s ein
sp
e ci f
i c v ol
um
e of
ab
o ut
4 5 0 f
ol d
(
H
a a s,19 9 0
)
.I
t
c
an
b
e
u s ed
a s ag
a s(
C l2
(g
)
)
g
e n e ra
t
ed
aft
e r su
p p l y i
n
g
t
h
et
h
e rm
al
en
e rg y
n e c e ss a
ry
t
o
t
h
e
va
p
o riz a
t
i
on
o
f
T h
eh
y
d
r oly
si
s of
chl
o ri
n
eg
a sin
w
at
e r o c c u r s a c c o rd i
n
g
t
ot
h
ef
ol l
ow i
ng
r e a c
t
io n :
C l
2+
H
20
-
*H 0 C 1
+
H
^
+
C r
K
h=
4
xl 0
-^
(
m
ol / L
)
^[
I I
.l
]
H
y
p
o ch l
o r o u s a ci d i
s a r el
at
i
v el
y
w
e ak
a ci d
t
h
at
w i l l
t
en
d
t
od is s o c
ia
t
ei
n
w
at
e rf
o rm i
n
g
h y d
r og
e n an
d h
y p
o ch l
o ri
t
ei
o n s :H O C l ^
H
^+
0 C 1
'p
K
a=
7
.5
[
I
I
.2
]
I
n
w
at
e r s of
p
H b
et
w
e e n6
.5
an
d 8
.5 w
e c an
e xp
ec
t
b
ot
h
sp
e cie s
t
obe
p
r e s en
t t
os o
m
ed
eg
r e e.T h
ed
eg
r e e of d i
si
n
f
e ct
io n
ob
t
ai
n ed w i l l d
ep
e nd g
r e at
l
y
o np H
a st
h
ed i
si
nf
e ct
io n
ef fi
cie n c
y
of H O C l i
sm
u
ch hi g h
e rt
h
an
O C l
"(M
aie r
et
al
.,2 0 0 0
)
.I
f h yp
o ch l
o ri
t
e s al
t
s a r e u s ed
t
od i
si
n
f
e ct
t
h
ew
at
e r,t
h
efo
l l
ow i
ng
r e a ct
io n s
o
c c u r :N
aO C l
+
H
zO
-
^H O C l
+
N
a
^
+
O H
-[
I I
.3
]
C
a(
0 C l
)
2+
2 H
2O
-
>2 H O C 1
+
C
a^^+
2 0 H
-[
I I
.4
]
T h
eh
y
p
o ch lo r o u s
a ci d w i l l
t
h
e nf
ol l
o
w
t
h
ed i
s s o cia
t
io n
r e a ct
io n
d
e s c ri b
ed in
[
11
.2
]
.I I
.A
.2
.D i
sin
fe c
t i
o n u si
n gC
om b i
n ed
C h
l
o ri
n eI
nt
h
ep
r e s en c e
of
am
m
on
ia
,w
at
e r ch l
o ri
n
at
io
n
w i l l l
e ad
t
o
t
h
ef
o rm
a
t
i
o
n of
c
h lo r a
m
i
n
e s(
m
o n o ch l
o r am i
n
e,d i
ch lo r a
m i
n
e o rt
ric
h lo r a
m i
n
e)
,w i
t
h
t
h
e r at
e s of
re
a ct
io n
a
n
d p
r od
uc
t
f
o rm
a
t
i
on
d
ep
e nd
en
t
o np H
, r el
at
i
v e c o n ce n
t
r at
io n
of N
H
t "^a n
d H O C l
,c
o nt
a ct t
i m
e a nd
t
em
p
e ra
t
u
r e.T
h
e o r et
ic a
l l y
, at
ch lo r
i
n
et
o am
m
o ni
aw
ei
g
h
t
r at
i
o sle s s
t
h
a n5
:1
a nd p H
v alu e s
b
et
w
e e n7
a nd 8
, c om
m
o n c on
d i
t
io n s
ap p
l i
ed d
u rin
g
d
ri
nk i
n
g
w
at
e r ch l
o r am i
n at
i
o n,m
o n o ch l
o ra
m
i
n
e(
N
H
2C I
)
w i l l b
et
h
ep
r ed
om
i
n
an t
f
o rm
i
nt
h
ew
at
e r[
I I
.5
]
.H O C l
+
N H
3^
N H
2C I
+
H
2O
[
n
.5
]
A t
la r
g
e r ch l
o ri
n
et
o am m
o ni
a r at
i
o sa n
d
l
ow
e rp
H
v alu e s
,t
h
eN H
2C I
c o n c e
n
t
r at
io n s
d
e c r e a s ew i
t
h
a ni
n
c r e a s ei
n
t
h
ed ic
h lo r a
m i
n
e(
N H C I2
)
c o n c e nt
r at
i
o ns
[
1
.6
]
.T
h
e ra t
e of
t
h i
s r e a ct
io n
w i l l b
em
u ch
slo
w
e rt
ha
n
t
h
em
o n o ch l
o r am i
n
efo r
m
at
io n
r e a c
t
io n
an
d w i l l i
n c r e a s ew i
t
h
t
h
ep
H d
e c r e a s e.N H
2C
I
+
H O C l ^
N H C I
2+
H
2O
[
I I
.6
]
I f
t
h
ep
H w
e r ek
ep
t
b
e
t
w
e e n7
a nd 8
a n
d
t
h
e ch l
o ri
n
e : am
m
o ni
aw
ei g h
t
r at
i
o s
i
n c r e a s ed
t o
ap p
r o xim
at
el
y
1 5
:1
,t
ric
h l
o r am
i
n ew
o ul d b
ef
o rm
ed
[
I I
.7
]
.N H C I2
+
H O C l ^
N C I
3(
t
ri
ch l
o r am
i
n
e)
+
H
2O
[
I I
.7
]
T he
b
r e ak p
oi
n
t
p h
e n om
e n o n o c c u r sw h
e n ch l
o ri
n
eis a
p p l i
ed i
n s uf fi
cie
n
t
d
o s e s(
chl
o ri
n
et
o am
m
o nia
m
ol
a r r at
i
o shi g h
e rt
h
a n1
.5
o rw
ei g h
t
r at
i
o sh i g h
e rt
ha n
7
.5
)
t
om
e et
t
h
e am
m
o ni
ad
em
a nd i
nw
at
e r a nd le a v
i
n
g
afr
e e ch lo r
in e r e s
i d
u al
[
I I
.8
]
.I
np
r a ct
i
c et
h
e ch l
o ri
n e t
o am m
on
i
am
ola r r a
t
io
t
en
d
st
ob
e cl
o s e rt
o2
t
o1
(
1 0
t
o1 b
y
w
ei
g
h
t
)
.2 N H
3+
3 H 0 C 1^ N
2(g
a s)
+
3 i
r
+
SC I
"
+
3 H
2O
[
11
.8
]
I
n
o
rd
e rt
o a ch i
e v edr
in
k i
n
g
w
ate r
d is
i
n
f
e ct
i
o n ,m
on
o ch l
o r am
i
n
ei
sf
o rm
ed
p
r efe r e n
ti
al l
y
at t
h
et
r e at
m
e nt
p
l
a nt
b
y
c on t
r ol l i
n
g
t
h
e cl
il
o ri
n e : am
m
o nia
r at
i
ot
o a v alu e
g
en
e r al l
y
l
e s st
h
a n5
:1
o n aw
e
i g h
t
b
a si
s(
ap p
ro
xim
at
el
y
1
:1
o na
m
ola r
b
a
sis
)
.T h
eM
o n o ch l
o r am i
n
ed
i
sp
r op
o rt
i
o n at
i
on
c an
o ccurb
y h y
d
r ol
y
si
s of
m
o n o ch l
o r am
i
n e(
d
e s c ri b
ed i
n
eq
u
at
i
o n[
I I
.5
] )
o rb
y g
en
e r al
a ci d
c at
al
y
si
s(
d
e s c ri b
ed i
n eq
u at
i
o n[
I I
.9
] )
i f
t
h
e
c o n c en
t
r at
i
on
of p
r ot
o nd
o n o r si
n c r e a s e s(
S
y
m
o n s et
al
.,19 9 8
)
.N
H
iC l
+
N H
sC l
+
H
^^
N
H
C
k
+
N
H
s+
H
^
[
I I
.9
]
V
al
e nt
i
n e a nd
J
af
v e rt
(
1 9 8 8
)
f
o u nd
t
h
at t
h
e c a rb
o n at
e sy
st
em
c a ni
n
c r e a s et
h
e r at
eo
f
a ci d
-c a
t
al
y
z ed d i
sp
r op
o rt
i
o n at
i
o n at t y p
i
c al
c o n c e nt
r at
i
o n s a nd
p
H
v al
u e s of d
ri
nk i
ng
w
at
e r.T h
ef
o rm
at
i
on
of b
r om
am
i
n
e s a nd b
r om
o ch l
o r am
i
n
e sh
a s al
s ob
e e nd
e s c ri b
ed i
n
t
h
el i
t
e r at
u r ew h
e n ch l
o r am i
n
at
i
o ni
s u s ed
a s ad i
si
n
f
e ct
a nt
of w
at
e r s c o nt
ai
ni
ng
b
r om i d
e(
S
y
m
on
s et
al
.,
19 9 8
)
.A
c c o rd i
n
g
t
ot
h
e s e au t
h
o r s,
t
h
e sp
e ci
at
i
on
of b
r om
am
i
n
e si
s,a s
f
o r ch l
o r am
i
n e s, af
u n ct
i
o n of
p
H
an
d
am
m
o ni
at
ob
r om i
n
e r at
i
o .B
r om
am i
n e sf
o rm f
a st
e r
t
h
an
chl
o r am i
n
e sb
ut t
h
ei
r c o nt
ri b
ut
i
on
t
od i
si
n
f
e ct
i
o ni
st
h
o ug
h
t
t
ob
em i
ni m
al
aft
e r2 4
to
4 8 h
o u r si
nt
h
ed i
st
ri b
ut
i
o n sy
st
em
b
e c a u s et
h
ey
a r e sh
o rt
-l i
v e
d
.T
h
ei
r r e a ct
i
vi
t
y t
of
o
rm
D B F
si
s n ot
w
el l d
o c um
e nt
ed
y
et
e v e nt
h
ou
g h l i
t t
l
ef
o rm
at
i
o n of
T
H
M
si
s e xp
e ct
ed
t
oo c c u r
fr
om d i b
r om
am i
n
e(
S
u
g
am
an
d H
el
z,19 8 0
)
.V
al
e nt
i
n e(
1
9 8 6
)
s ug g
e st
ed
t
h
ep
o s si b i l i
t
y
of
a ni
m
p
o rta n
t
c on t
ri b
ut
i
o n of
b
r om
o ch l
o r am
i
n
et
oD B F
p
r od
u ct
i
o ni
n
b
r om
i d
e c o nt
ai
n
i
n
g
w
at
e r sd
u et
ot
h
eh i g h
r e a c
t
i
vi
t y
of i
t
sb
r om i
n
e at
om
.T h
ed
efi
n
i
t
i
on
of
t
h
et
e rm
sfr
e e ch l
o ri
n
e, c om b i
n
ed
ch l
o ri
n
e, a nd
ch l
o ri
n
e r e si d
u al
a r e