Ara chlorine or chloramine toxic
to people in the amounts used to
treat water? .-

in the amounts used to treat water, no.
Neither chlorine nor chloramine enter
the blood stream when humans drink it.

Ave there legal lHabilities if fish are
kilted as a result of a watermain
break?

Yes. The Department of Fisheries and
Oceans can fine the GVRD or a member
municipality if chlorinated or
chloraminated water enters tish-bearing
waters. Fisheries has serious reserva-
tions about the use of chloramine.

if chloramine is so stable, does it
ever break down?

Yes. Chioramine breaks down on contact
with material such as sewage, dirt, and
large volumes of water.

Mas an environmental impact
assessment been conducted?
What were the findings? —

Yes, an environrnental impact assess-
ment was.conducted. The assessment
concluded that although both secondary
‘disinfectants are potentially lethal to fish,

* chloramine is of greater concern

because it lasts longer.

Are there ways to minimize fish

kills, or at least reduce the effect
ofa watermain break?

Yes. Automatic dechlorination units can
be designed and sited throughout the
region to neutralize chlorine or -
chloramine. in addition, an emergency
-T@sponse program can be implemented -
to respond to spills of treated water that
‘May result irom watermain breaks. The .

"emergency response program has

proven successful in Surrey. However, it

. Is impossible. fo guarantee there will be

no disinfectant-related fish kills with
either disinfectant. ;

“What other disinfectants did the
GVAD consider? :

A range of primary and secondary
disinfectants were considered, including

“higher levels of chlorine, chloramine,

ozone, chlorine dioxide, ultraviolet light,
and potassium permanganate.

° Can ozone be used to disinfect

_ our water?

s Ozone could: replace chlorine asa

primary disinfectant, but because it does

not remain in the. water for more than a

-few.minutes additional treatment is
fequired. -iIn Montreal, for instance,
ozone is used as an effective primary

‘disinfectant, but tne water goes through

a'filtration plant first and is also treated
vith chlorine. lf ozone is used here as a
‘primary disinfectant, filtration and the

"addition of a secondary disinfectant

rechlorination: of chloramination) will stil!
‘be required.

Could ozone booster stations be
Ui? :
‘No; Ozone lasts only a few minutes in

‘waist. ‘Siting an ozone booster station
very bi tock would still not be adequate.

: Could biological filtration be used

* “here? .

“Yes. This technology could be used here
‘combined with ozone and a secondary

- disinfectant (either chlorine or

chloramine). Ozonation and biological

filtration could augment any of the
options and wouid cost about S100 more

“per household per year than allt year than all the other

The Greater. |

~- Vancouver. Water.
System serves
18 municipalities

options. This process would produce the
highest quality drinking water but would
still require a low level of secondary
disinfectant such as chloramination or
rechlorination,

Would improved maintenance of
the pipe system reduce the need
for costly improvements ?

No. While pipe maintenance will help
reduce bacteria levels, a secondary
disinfection residual {either increased
chlorine or chtoramine) must be main- —
tained to control bacteria in the water
system.

Has the GVRD made a decision
about secondary disinfection?

No recommendation has been made
and no decision has been reached.

All input to the current public consulta-
tion process will be evaluated before the
Board of Directors makes a decision,
which is expected this year.

Water treatment experts retained by the —

GVRD say the only suitable secondary
disinfection methods that will meet

health requirements are rechiorination cr

chloraminaticn. Their reports, which are
available to the public, will be considered
by the GVRD's Water Committee and
Board of Directors, along with all com-
ments and submissions from the public.

| Why is filtration required?

Filtration is required to remove sus-
pended material (dirt) that is found in
drinking water. This material is deposited
during periods of heavy rain and re-
duces the effectiveness of the primary
disinfectant (chlorine), which is added
near the watersheds to kill bacteria and
giardia.

Would the construction of

Sunday, March 27, 1994 - North Shore News - 35

‘disinfection: of the water supply nea
“the source. This process current

filtration plants reduce the amount ff filtration will be required i in the

of disinfectant needed?

Yes. Although the use of disinfectants
cannot be eliminated entirely, the

amount requised in the water system can -

be reduced by about 10% once filtration
plants are built. Biological filtration
would reduce the use of disinfectants
even further. The number of
rechlorination stations required would be
reduced by half if filtration piants are
built.

Why is the water cloudy
sometimes?

Cloudiness occurs when heavy winter
rains in the watershed cause erosion,
flooding and natural slides in steep
unstabie areas.

_ ls logging responsitie for water

cloudiness (turbidity)?

No. In 1991, an independent panel of
experts concluded that small-scale
logging does not appear to create water
quality problems. The panel stated that
“halting of logging in the watersheds
would not cause the issue of water
quality improvements measures, includ-
ing filtration, to be abandoned”

Is filtration at all three sources
ultimately required?

It depends. if rechlorination is chosen as
a secondary disinfectant, all three
reservoirs will likely require filtration to
meet public heaith standards. If
chloramination is selected, only two
reservoirs would require filtration’, and
the filtering can be deferred a number of
years if desired.

The Greater Vancouver
Water System includes
six.dams and
six storage lakes

next two decades anyway, wh yo
Not build the plants now?

Filtration plants could be built at all
sources simultaneously, but this may not

be economicaily feasible. Filtration couid «

be phased-in gradually to ease the
burden on taxpayers.

fs fittration of the Seymour
reservoir required only if the dam
is raised and rechlorination i is
selected?

No. Although filtration of both the
Seymour and Capilano sources can be
deferred if chlorainination is selected, it
will ultimately be required if Canadian
Drinking Water Quality Guidelines are to
be fully met.

What are the options?

The GVRD has developed a number of
options (shown in chart on page four) to
address these problems. ~

The first step in the decision process is
to select which secondary disinfectant

“be deterred or phased- -in.. =

Once a secondary disinfectant i is cho-
sen, the decision about which source to’

tap first can be made: Tapping an
‘expanded Seymour.source will require a

significant capital investment, while
drawing more water from Coquitlam will.
require extensive negotiations with BC
Hydro and compensation for, lost power
generation revenues. .

The decision about how to upgrade the

Seymour Fails Dam to earthquake |

standards — through retrofitting or
construction of a new dam.— canbe °
made after decisions about disinfection -
and the future supply source have been
made. ©

Who willdecide?,

The GVRD Administration Board is
expected to make a decision this year.
Each municipality that receives GVRD.
water is represented on the Board.

should be used. This choice may dictate _

‘how quickly the GVRD must &F7_
build the first filtration plant.

lf chioramination is selected,
disinfection by-products are
not a concern, so filtration
can be implemented now or.
phased-in gradually to reduce
cloudiness.

If rechlcrination is selected
and disinfection by-products
are a concern, filtration will be
required at all three sources
simutianeously.

If disinfection by-products are
not a concern, filtration can

| The Greater
Vancouver Water
System has
22 service reservoirs

Fhe Greater Vancouver
_Water System has -
550 kilometres of

water mains