Chritsine Labelle, Frédéric Forge
Science and Technology Division
16 February 2001
TABLE OF CONTENTS
PROBLEM: BETTER WATER MANAGEMENT
THREATS TO WATER
RESOURCES IN CANADA
A. Fresh Water An Abundant Resource
B. Fresh Water Massive Consumption
C. Degradation of Aquatic Ecosystems
D. Climate Change
E. Poor Understanding of Groundwater
F. Bulk Removals of Water
MANAGEMENT OF WATER IN CANADA
A. Federal and Provincial Responsibilities
B. Canadian Water Legislation
C. International Cooperation
D. Other Water Initiatives
THE FUTURE OF
WATER: CANADAS VISION
APPENDIX 2: WATER USE IN CANADA
APPENDIX 3: WATER TREATMENT IN CANADA
At the dawn of the 21st
century, half of the Earths supply of available fresh water(1) is used to meet human needs, which increased spectacularly over the
past century. All indications are that human consumption is not about to change
soon, that world demand will continue to grow, and that it will become critical in the
Canadians live in a country
that is plentifully endowed with water, and it ranks near the top in terms of renewable
fresh water. In spite of this abundance, Canada knows that it will have to adopt
effective management strategies to protect this valuable resource.
The purpose of this report is
to determine how well prepared Canada is to face an impending water crisis and its vision
of how the resource ought to be managed. The first two sections briefly
describe the situation for Canada and the world. The next section gives an overview
of the Canadian water use management framework and the steps it has taken in this
area. The final section deals with Canadas vision of water management against
the backdrop of international issues.
A GLOBAL PROBLEM: BETTER WATER MANAGEMENT
The amount of water used for
human needs has doubled in the past 35 years. Estimates show that it has increased
sixfold in the past 100 years,(2) and the increase cannot
be attributed to population growth alone, because the worlds population has only
tripled during the same period.
This increased use
combined with inadequate water management is the source of a host of problems,
At the moment, the available
fresh water in the world (including surface water and groundwater) is approximately
40,000 km3 per year.(4) In 1995,
estimated water consumption, whether diverted or pumped for human use, was 3,800 km3
(approximately 10%). Of this volume, 2,000 km3 are for direct
consumption, with the rest discharged into the environment after being used for a variety
According to analyses carried
out in 1995 by the World Water Council (WWC), if world policies remain unchanged and
current upward economic trends continue as forecast, the need for water will increase
considerably by 2025.(6) Water consumption might then
reach somewhere between 4,300 and 5,200 km3 and lead to water stress at the
world level, particularly in Africa, Asia and Latin America. Furthermore, in view of
world demographic growth, the average annual volume of water available per inhabitant will
decrease from todays figure of 6,600 m3 to 4,800 m3
Part of the problem stems from
the fact that not all available water resources are accessible or usable.(8) Indeed, much of the water is located in areas that are inaccessible
and thinly populated, particularly some of Canadas Northern regions, Alaska and the
Amazon basin. Furthermore, many tropical river basins only contain large quantities
of water for short periods of the year.
On the other hand, problems
related to managing the use of water may explain why these resources are less plentiful
elsewhere in the world, particularly in the temperate river basins of many Northern
countries. Intensive human use in addition to the consumption involved in
such use pollutes both surface and subterranean water resources, making quality
water harder to find.
In short, the results and
analyses published by the WWC make it absolutely clear that there is already a world water
crisis. It stems not so much from a shortage, but from poor management, and millions
of people are currently suffering as a result. The Council feels that it has become
urgent to adopt sustainable water resource management and food production policies.
It therefore advocates five major measures that would make it possible to introduce such a
management system by 2025:
These measures should
contribute to achieving a variety of objectives, including:
THREATS TO WATER RESOURCES IN CANADA
A. Fresh Water An
Canada has one of the
worlds largest supplies of fresh water.(9) It has
9% of the worlds renewable fresh water (it actually has 20% of the worlds
fresh water, but only part of the reserve is accessible, with the rest consisting of
inaccessible or fossil water(10).
Canadas renewable fresh
water reserve consists of:
lakes and water courses,
which make up almost 8% of Canadian territory, and wetlands, which account for 16%; and
Because Canada is so big and
some parts of the country are inaccessible, 90% of the population has access to only 40%
of the water.
B. Fresh Water
Canadians use an average of
326 litres of water per person per day, making this country one of the worlds
biggest consumers of drinking water.
The chart prepared by
Environment Canada and shown in Appendix 2 illustrates various aspects of water use
by area of activity in Canada.
Users other than the
transportation and tourism sectors consumed 57.9 billion cubic metres of water(11) in 1991, broken down as follows:
Even though the supply of
drinking water does not, at first glance, seem to be a problem for Canadians, 17% of
municipalities with a watermains system experienced supply problems in 1994.
Increased consumption has a direct effect on the volume of wastewater that must be treated
and increases the cost of both supplying and treating (see Appendix 3) water.
of Aquatic Ecosystems
Human activity is one of the
biggest threats to fresh water. All areas of industrial activity have a real impact
on aquatic ecosystems. For example:
effluents produced by the
manufacturing and mining industries and discharged into the natural environment usually
display chemical, physical or biological characteristics different from those of the water
before it was used, even after treatment;
Some of the major changes
caused to the aquatic environment by human activity are:
These factors not only lead to
habitat loss and a decrease in biodiversity, but also contribute to a build-up of toxins
in the food chain and to a decline in the quality of water prior to treatment.
Even though approximately 90%
of the water used in Canada returns to the environment, the loss mainly
attributable to evaporation during use has an impact on aquatic ecosystems,
particularly in areas that are susceptible to drought.
Consequently, many problems
persist; action to prevent pollution and achieve efficiency gains is becoming ever more
vital and pressing.
D. Climate Change
Debate continues on planetary
climate change, concerning both whether it exists and its possible effects.(12) Some computer models can develop scenarios,
particularly for the possible impact on water and various water-related activities.
The conclusions vary
considerably. For example, experts at the National Oceanic and Atmospheric
Administration (NOAA) in the United States and at Environment Canada believe that global
warming will lower water levels in the Great Lakes by a metre or more over the next 50
years. On the other hand, scientists from the U.S. National Assessment on the
Potential Consequences of Climate Variability and Change think it possible that
there could be either a slight increase or a decrease in lake levels.(13) Despite the high degree of continuing uncertainty
about the extent of the observed changes, analyses of circulation in the Earths
atmosphere would appear to indicate that warming will change global precipitation
The International Joint
Commission (IJC) whose mandate is to govern relations between Canada and the United
States with respect to boundary waters believes that a decline in water levels
could occur as a result of climatic change. For the Great Lakes, any drop in water
level could have a number of consequences, including:
In short, lower water levels
could have a major economic, social and environmental impact on the entire Great Lakes
E. Poor Understanding of
Most groundwater is derived
from rainfall infiltration into the ground, at rates that vary with porosity.(14) Water from the water table, which is the main
Canadian source of fresh water, meets the needs of over 7.9 million people or about 26% of
Consumption varies from
province to province. For example, groundwater accounts for only about 20% of the
drinking water consumed by Quebeckers.(16) However, in
other provinces and territories, its use is more significant: the entire population
of Prince Edward Island and 60% of the people in New Brunswick and the Yukon rely on
groundwater to meet their drinking water needs. It is worth noting that these
regions face shortages more often than regions that can use surface water.
In recent years, the abundance
of groundwater has led some entrepreneurs to consider using it for major commercial
projects, such as bottling it for export.(17) Projects
of this kind are controversial and widely debated, partly because of a current lack of
understanding of the water table.
In a report issued in February
2000, the IJC described the Canadian and Great Lakes groundwater system.
According to the Commission:
F. Bulk Removals of Water
Bulk removal means
the removal and transportation of large quantities of water away from its original basin
by means of man-made resources (canals, boats, tanker ships, pipelines).(18) The term does not necessarily mean that water is transported outside
its province or country of origin (exported). Likewise, it does not include
small-scale removal (small portable containers).
Bulk removal projects
presuppose that the water removed will be lost permanently from the basin concerned.
Furthermore, such projects may involve the diversion of watercourses and the construction
of dams that are likely to take a toll in the form of huge social costs. Some
possible problems include:
Bulk removal of water is
accordingly considered to be a non-sustainable use of the resource and that is why the
Government of Canada wants to ban such removals from major drainage basins.(19)
The aim of Bill C-15, An Act
to amend the International Boundary Waters TreatyAct, which was tabled in the House of
Commons on 22 November 1999 by the Minister of Foreign Affairs, was to protect
cross-border waters from extensive water removals. In particular, the bill was
intended to clarify the existing Act and to make the implementation of the 1909 Treaty
relating to Boundary Waters and Questions arising along the Boundary between Canada and
the United States (commonly called the International Boundary Waters Treaty)
more effective by:
providing for specific
penalties and punishments for offences a ban on damming boundary waters would apply
primarily to the Great Lakes, but would also affect other boundary waters, including part
of the St. Lawrence, the St. Croix River, the upper waters of the St-Jean River, and Lake
of the Woods.
Although Bill C-15 died on the
Order Paper with the calling of the federal election on 22 October 2000, a similar
bill (C-6) was introduced on 5 February 2001 at the beginning of the 37th Parliament.(20)
The IJC which in 2000
issued a report on the subject at the request of Canada and the United States in the
context of the federal bulk-water removal strategy believes that governments ought
not to authorize bulk removal of water from the Great Lakes unless the proponent can
demonstrate that there will be no impact on the ecosystems. Again according to the
IJC, this approach would satisfy Canadas trade obligations. Governments in
fact have sovereignty over the management of water in its natural state and are not bound
by trade agreements.(21)
Lastly, the Canadian Council
of Ministers of the Environment also holds the view that the extraction of water from the
main drainage basins should be prohibited for the near future.
GOVERNMENT MANAGEMENT OF WATER IN CANADA
A. Federal and
The question of what action
ought to be taken to protect water is inseparable from that of the respective
responsibilities of the federal and provincial governments for the management of this
natural resource. Under the Constitution Act, 1982.(22)
navigation on the high seas and in domestic waters;
waters located on
federal lands, in the territories and on Indian reserves as well as
cross-border waters; and
implementation of international treaties signed on Canadas behalf.
It can also make laws for the
peace, order and good government of Canada.
The provinces have
jurisdiction over the operation, conservation and management of ground and surface
water. This means that they are responsible for handling projects involving
regulation of the flow and use of water and for enacting legislation governing water
supply, pollution, and thermal and hydro-electric power. As municipal governments
come under the provinces, they may be delegated almost all the jurisdiction conferred on
the provinces by the Constitution, including the powers relating to regulations governing
water purification, sewers or the protection of riverbanks, shorelines and flood
plains. Regulations of this kind have a considerable impact on the quality of
Some activities fall under
both federal and provincial jurisdiction, such as activities related to border or
cross-border waters, and activities related to agriculture or health when a major national
water problem arises.
B. Canadian Water
The obligations arising from
the above-mentioned responsibilities have given rise to numerous statutes that make it
possible for Canada to manage water in certain areas. Noteworthy statutes include
the following Acts:
However, there is no single
federal statute governing all aspects of water resources in Canada, and most of the
above-listed statutes deal with specific sectors.(23)
The Canada Water Act,(24) which enables the federal government to play a
leadership role in fresh water management, was enacted in 1970, the year before the
Department of the Environment was established (1971). It provides for consultation
between the federal and provincial governments on any issue relating to water resources
and includes provision for the application of unilateral federal measures in the event of
Projects arising out of this
process are currently under way, including:
Bilateral agreements have been
signed for all of these programs. The agreements set out a number of things,
including the contribution to be made by each level of government in terms of funding and
the provision of information and expertise. The 1998-1999 annual report on water
resources includes the recent agreements for these programs. By implementing the Canada
Water Act, Canada is encouraging an approach that focuses on partnership between the
various levels of government and the private sector.
The Federal Water Policy(25) was drafted by various levels of government in 1987,
with a view to improving water management. Through this policy, the federal
government is working to protect and improve the quality of water resources while
encouraging prudent and effective water management and use. The policy also deals
with the importance of raising public awareness of the need for rational daily use of
water. Five strategies were put in place as a result of the policy. These five
strategies correspond to action plans that define the governments supporting role
and make it possible for the partners (federal agencies, other levels of government,
industry) to deal with specific situations and challenges in this area.
In addition to the Canadian
legislative and administrative tools described above, two sets of recommendations deserve
mention: those on the quality of Canadas water published by the Canadian
Council of Ministers of the Environment in 1987; and those on drinking water quality in
Canada developed by Health Canada in 1989.
The Canada-U.S. border passes
through many watercourses and all the Great Lakes,(26)
except one. The International Joint Commission (IJC) which was established under the
International Boundary Waters Treaty of 1909, and which has six members
three appointed by the President of the United States and three by the Canadian Cabinet on
the advice of the Prime Minister is the agency assigned responsibility for
governing relations between Canada and the United States with respect to boundary
waters. It established bilateral councils to facilitate investigation, control and
monitoring under the Treaty.
The IJC reviews applications
for approval of projects relating to boundary and cross-boundary waters and may regulate
the operation of such projects. It helps both countries to protect the environment
in border areas, including enforcement of the Great Lakes Water Quality Agreement of
1972, and keeps the governments informed about new risks that might lead to disputes
between the two countries.
Canada is also a participant
in a number of global initiatives. For example, it produced a joint report on water
management in North America in partnership with the United States and Mexico. This
report stems from the Global Water Vision initiative established in 1998 by the
World Water Council (WWC) to achieve international consensus on the implementation of a
management plan to deal with the current water crisis.
Since 1998, individuals and
organizations have joined in discussions organized by the WWC with professionals and
stakeholders. Sectoral and regional consultations were held and regional reports
were issued. These reports including the one prepared by Canada, the United
States and Mexico entitled North America led to the drafting of the
comprehensive report entitled World Water Vision Making Water Everybodys
Business.(27) In addition to providing an overview
of the world situation with respect to water management, this report sets forward
solutions intended to provide access to drinking water for people by means of management
plans that will guarantee the integrity of aquatic ecosystems.
D. Other Water Initiatives
For 12 years now, initiatives
have been developed within Canada to deal with the problems described above. These
initiatives, which focus on ecosystems, take into account not only environmental but also
economic and social concerns.(28) They are the product
of partnerships between the federal and provincial or territorial governments and often
require the cooperation of individuals, communities, Aboriginal peoples and private
Canadian Water-Related Measures
Strategies for Action
|St. Lawrence Seaway project
|Great Lakes Water Quality
Agreement (revised in 1989)
|Agreement on water supply and
flood protection in the Souris River basin
|Treaty relating to boundary
waters and questions arising along the boundary between Canada and the United States
(International Joint Commission)
|Lake of the Woods Agreement and
|Rainy Lake Agreement
|Treaty concerning the diversion
of the Niagara River
|Columbia River Treaty (1961) and
|Treaty concerning the Skagit
River and Ross Lake and Seven Mile Reservoir on the Pend dOreille River
and Provincial Strategies
|The Canada Water Act
creates a consultation process between the federal and the provincial governments on any
question relating to water resources.
|The Federal Water Policy
enables the government to protect and improve the quality of water resources while
encouraging prudent and effective management and use of water.
Websites of the International Joint Commission, the Commissioner for the Environment and
Sustainable Development, and Environment Canada, June 2000.
For example, the
ecosystems-based approach was used to develop the St. Lawrence Action Plan of 1988,
which is now in its third phase. The program has three objectives:
The past 12 years of work have
led to major successes: a 96% reduction in high-priority industrial discharges, the
creation of the Saguenay Marine Park, an increase in the beluga whale population, the
protection of 12,000 hectares of wildlife habitat, and the creation of ten community
groups for action (priority intervention zones committees ZIPs) along the
St. Lawrence. Over the next few years, Phase III of the St. Lawrence
Action Plan will be concentrating on preventive action in the following areas:
biodiversity, agriculture, industry and shipping. Community organizations will play
an active role in projects to clean up the St. Lawrence ecosystem.
The following table lists a
number of current major initiatives that favour an ecosystem-based approach and whose aim
is to revitalize aquatic ecosystems from coast to coast.
Completed in 1998
|St. Lawrence Action Plan
Vision 2000 (SLV 2000)
Great Lakes 2000
Northern River Basins Study/Northern Rivers Ecosystem
Atlantic Coastal Action Program (ACAP)
Fraser River Action Plan (FRAP)
Georgia Basin Ecosystem Initiative (GBEI)
Northern Ecosystem Initiative
Source: Environment Canada website,
FUTURE OF WATER: CANADAS VISION
In view of the current
problems including more frequent periods of drought in the Western provinces; the
quality of drinking water, which is sometimes unsatisfactory in certain regions; and
increasing demands for water exports Canadian governments believe that improving
the water management system has become urgent. In this, they agree with the World
Water Council, which argues that it is important to manage the world water crisis by
taking action to improve management of the resource by 2025.(29)
Water has been a concern to
Canada since 1909, and its management structure is very highly developed. Many
obstacles have been overcome thus far, but others need to be seriously examined. For
example, the Great Lakes, the Fraser River and the St. Lawrence River, where many efforts
to clean up these bodies of water have already been implemented, need further work in the
medium and longer term to eliminate toxic pollution from farming, and from urban and
industrial pollution. In addition, Canadas water resources are overused (given
that the largest part of the population has access to only 40% of fresh water), which will
lead to the spending of billions of dollars in supply infrastructure and wastewater
Many initiatives are based on
action advocated by the WWC, including the following:
Most governments in this
country want to continue to work towards improving Canadian water resource
management. Environment Canada, which is constantly developing integrated management
tools, promotes cooperation among governments and strives at all times to meet sustainable
development objectives. The Department therefore promotes projects such as community
or voluntary measures, basic research and more technical solutions
(e.g., installation of meters).
In a report on the health of
the countrys water prepared in 2000 by Agriculture and Agri-Food Canada, the
Department emphasized the importance of creating management tools that would make it
possible to use groundwater in a sustainable manner. According to research by the
Department, the consequences of drought in Western Canada will worsen as a result of
parameters such as climate change or population growth, urbanization and water demand.(31)
daudiences publiques sur lenvironnement [Environmental Public Hearings Board],
or BAPE, which conducted hearings on water in 1999, concluded in a report published in
2000 that current management of water and aquatic environments is spread among too many
sectors, poorly integrated and insufficiently concerned with the environment.
According to BAPE, it is urgent to:
move to integrated management
that is better harmonized at the government level, combine the functions of protection and
enhancement, and specifically target individual drainage basins. Moreover, immediate
action can and must be taken, and it needs to be consistent with future policies.(32)
Among other things, BAPE
Lastly, Canadas work
with the United States and Mexico(33) has led it to
conclude that a pan-North American approach to water will require intersectoral and
cross-border cooperation at all levels.
However, one thing is
certain: participation by an informed public will have to be the starting point for
action by governments and management organizations in the public and private
sectors. The greatest challenge will be to integrate water management at all levels
from the ordinary individual user to the bodies responsible for administering major
water basins and to ensure that everyone participates in the decision-making
process. In this way, all parts of society will have a role to play in a genuinely
integrated Canadian water management system.
Definitions of various water terms are given in the Glossary (see Appendix 1). For a
brief version of this report, see Christine Labelle, Water
Management in Canada: Related Issues, TIPS-37E, Parliamentary Research
Branch, Library of Parliament, 30 November 2000.
William J. Cosgrove and Frank R. Rijsberman, World Water Vision Making Water
Everybodys Business, World Water Council, 2000.
This has also led to positive results for people and the environment, for example, the
creation of water treatment systems (see Appendix 3).
The report prepared for the World Water Council by Cosgrove and Rijsberman (2000) refers
to blue water and green water. Blue water, which includes
surface water and groundwater, is the main source of water for human purposes and the
subject of water resources management. Green water corresponds to rain water and is
the main source of supply for natural ecosystems and agriculture that does not rely on
irrigation (it produces 60% of the worlds food).
Generally speaking, the quality of discharged water has been seriously altered.
Industrial applications use the most water, double what is consumed for domestic
purposes. In these contexts, water is used primarily as a cooling agent in
The variation depends in part on any expansion in irrigation for agricultural
purposes. See Cosgrove and Rijsberman (2000), p. xxi.
See Cosgrove and Rijsberman (2000).
Brazil is first with 18% of the world reserve, followed by Canada and China (9%) and the
United States (8%). Environment Canada, A Primer on Fresh Water,
website, October 2000, http://www.ec.gc.ca/water/en/info/pubs/e_pubs.htm.
Fossil water is a vestige of the ice sheets that covered the Earth during the Pleistocene
era. See Environment Canada, A Primer on Fresh Water, October 2000.
Of that volume:
more than 12.8 billion cubic
metres are recirculated in various industrial sectors;
4.3 billion cubic metres are
consumed in other words, use leads to the water evaporating or being incorporated
into products or organisms and no longer available for other purposes;
more than 40.4 billion cubic
metres are returned to the environment after being used and become available again
(Source: Environment Canada, Water Use in Canada in 1991, website,
See Tim Williams and Jean-Luc Bourdages, Global
Warming and the Willingness to Reduce Greenhouse Gases, TIPS-39E, Parliamentary
Research Branch, Library of Parliament, 1 December 2000.
International Joint Commission, Final Report on the Protection of the Water in the
Great Lakes, submitted to the governments of Canada and the United States of America,
22 February 2000.
Normand Grondin, Les eaux souterraines : ce quil faut savoir, Québec
Science, September 1997.
Environment Canada, Almost 8 Million Canadians Depend on Groundwater, water
website, March 2000, http://www.ec.gc.ca/water/.
Stéphane Gagné, Les eaux souterraines : une ressource convoitée, Le
Devoir, 6 December 1997, p. F6.
International Joint Commission (2000).
Environment Canada, General Information on Bulk Removal and Export of Water, The
Green Lane, August 2000. See also David Johansen, Bulk
Water Removals and the NAFTA, TIPS-20E, Parliamentary Research Branch, Library of
Parliament, 4 February 2001.
Department of Foreign Affairs and International Trade, Implementation of a Strategy to
Prevent the Bulk Removal of Water from Canada, Including Water for Export, News
release, 10 February 1999.
See David Johansen, Bill
C-6: An Act to amend the International Boundary Waters Treaty Act, Legislative
Summary LS-383E, Parliamentary Research Branch, Library of Parliament,
12 February 2001.
Department of Foreign Affairs and International Trade, Canada Welcomes with
Satisfaction the Report of the International Joint Commission on Protecting the Water of
the Great Lakes, Departments website, 15 March 2000,
See Report of the Standing Committee on the Environment, The Environment and the
Constitution, House of Commons of Canada, March 1992.
International Joint Commission (2000).
Environment Canada, Canada Water Act Annual Report 1998-1999.
Environment Canada, Federal Water Policy, 1987.
The Great Lakes and St. Lawrence Basin contain one-fifth of the Earths fresh water
Cosgrove and Rijsberman (2000).
Environment Canada, Ecosystem-based Initiatives, information paper.
See earlier section entitled A GLOBAL PROBLEM: BETTER WATER MANAGEMENT.
Canada Mortgage and Housing Corporation, The Ecological City: Canadas
Overview, Federation of Canadian Municipalities, May 1995.
Agriculture and Agri-Food Canada, The Health of Water Toward Sustainable
Agriculture in Canada, 2000.
BAPE, Leau, ressource à protéger, à partager et à mettre en valeur,
extract from general findings, website, June 2000.
World Water Vision: North America, website, June 2000, http://www.gwpforum.org/worldwatervision.htm.
used in such a way that it evaporates.
(2) Water incorporated into products or organisms and thus no longer
available for other purposes.
Water diverted from a watercourse or pumped from ground water for human use.
Water generally containing less than 1,000 mg/L of dissolved solids such as salts, metals,
nutritional elements, etc.
Reserves of water stored below the earths surface (normally in aquifers), often the
source of springs and wells.
Water is regarded as an inexhaustible or renewable resource, because human activities do
not affect the biospheres total water reserves, even though the length of
waters life cycle varies depending on where it is found and the use that is made of
it. However, to be useful, water must be of a certain quality and physically
available. It is therefore also regarded as a scarce resource and sometimes even as
non-renewable, especially because of a life cycle that can be extremely long.
Any water naturally in free contact with the atmosphere (water courses, lakes, reservoirs,
retention ponds, the sea, estuaries, etc.) The term also covers springs, wells and
other collectors directly influenced by surface water.
Used water: Resources
drawn from surface and groundwater for human use. A portion of this water is
discharged into the environment after use and so becomes available again.
system: Conduits, pumping stations, force mains and all other infrastructures
and installations used to gather wastewater and transport it to a given point for
treatment or discharge.
The study, planning and oversight of water resources and the application of quantitative
and qualitative development and monitoring techniques designed to ensure the multiple and
long-term use of the various forms of the water resource.
Term used to describe the chemical, physical and biological characteristics of water
relative to a given use.
WATER USE IN CANADA
Source: Environment Canada, The Green Lane,
WATER TREATMENT IN CANADA
To prevent diseases caused by
water-borne pathogens, drinking water is disinfected in one of three ways:
chlorination, ultraviolet light, and ozonization.
Chlorination is the most
commonly used technique because it is effective in killing fecal coliforms and other
bacteria and other micro-organisms. Ultraviolet disinfection, in which light energy is
used to destroy pathogens, is an alternative to chlorination. Water ozonization is also
used in Canada. Ozone and ultraviolet light are effective, but they disinfect water
only temporarily, whereas chlorine continues to disinfect water as it moves through the
In Canada, wastewater is:
Wastewater can be treated in
one or more of the following ways:
After undergoing preliminary treatment to remove grit and solid material, wastewater goes
through a completely physical process that separates solid matter from liquid.
Floating, oily and greasy material is removed from the effluent, and the resulting sludge
can be disposed of in a number of ways. If the effluent is not treated further, it
is simply returned to the environment. Generally, primary treatment without
chemicals reduces biochemical oxygen demand (BOD) by 25% to 40% and removes between 40%
and 60% of solid matter in suspension.(1)
Secondary treatment, also known as biological treatment, may follow primary
treatment. The process consists of introducing micro-organisms into the pool
containing the liquid effluent and giving them enough oxygen to survive so that they can
feed on the organic matter. This technique considerably reduces the quantity of
solid matter in wastewater. The resulting sludge is treated further or returned for
additional biological treatment. Secondary treatment reduces BOD by 85% to 95% and
eliminates up to 99% of coliforms.
Tertiary treatment involves the use of technologies that supplement other treatments; the
choice of supplementary technologies depends on the characteristics of the wastewater
being treated. Additional filters may be added, such as carbon filters or other
specialized filters that remove metals, chemicals and other types of contaminants.
In addition to further reducing the amount of suspended matter and BOD, tertiary treatment
helps eliminate such substances as phosphorous and nitrogen or ammonia.
Chlorine is sometimes used in
the last stage of wastewater treatment, just before the water is discharged into the
Primary treatment is used in
British Columbia, while the Prairie provinces favour secondary treatment. Ontario
has opted for tertiary treatment. All three types are used in Quebec to varying
degrees, although tertiary treatment is less common. In the Atlantic provinces, half
the population is served by sewer systems which discharge untreated wastewater directly
into estuary or coastal waters that are considered unable to properly dilute the material.
Sierra Legal Defense Fund, The National Sewage Report Card Rating the treatment
methods and discharges of 20 Canadian cities, June 1994.