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Water is one of the most important substances on earth, and without proper preservation and management, we will continue to see fresh supplies depleted and spoiled by contamination. Abuse of current supplies will limit future resources, with consequences to our health and economy.
About 70% of the earth is covered in water. 97% of the water is saline, with the remaining 3% being fresh water. Of the fresh water, 0.3% is stored in lakes and rivers, 30% is groundwater, and 68% is trapped in ice and glaciers.
This leaves a very small percent of water on earth which is actually usable. There are one billion people who lack access to safe drinking water, and 2.4 billion to adequate sanitation. Because of this, every year 1.8 million people die from diarrhoeal diseases (including cholera); 90% are children under five, mostly in developing countries.
Canada is very fortunate to have one of the world’s largest supplies of fresh water; we have about 25% of the world's wetlands – the largest wetland area in the world. Wetlands totaling an area of more than 1.2 million square kilometers cover about 14% of the land area of Canada. However, most of the fresh water in Canada is located underground. There are currently 2921 active water level and streamflow stations being operated across Canada.
With a seemingly limitless supply of clean water coming from our taps, many Canadians forget the importance of protecting this resource. Taking water for granted has led to the pollution of many of our lakes and groundwater, and with aquifers drying up south of the border, there is a growing strain on Canadian water supplies. Despite Canada's stringent guidelines for good drinking water, health problems related to water pollution in general are estimated to cost Canadians $300 million per year.
Ontario and the Great Lakes
The Great Lakes are the largest system of fresh, surface water on earth, containing roughly 18% of the world supply. They support 33 million people, including nine million Canadians and eight of Canada's 20 largest cities. The Great Lakes Basin is home to 90% of Ontario's population and 40% of Canada's economic activity – the Great Lakes support 45% of Canada's industrial capacity.
With such importance to our lifestyle and economy, the Great Lakes have been, and continue to be, heavily abused. More than 360 chemical compounds have been identified in the Great lakes, many of which are persistent toxic chemicals – alkylated lead, benzo(a)pyrene, DDT, mercury and mirex – potentially dangerous to humans and already destructive to the aquatic ecosystems. For example, various species of fish now suffer from tumours and lesions, and their reproductive capacities are decreasing
In Ontario, approximately 8.9 million people receive their drinking water from municipal water works; 66% of which comes from the Great Lakes basin. Due to agricultural drainage and urban encroachment the wetlands of Lake Ontario have suffered severe loss over the last two centuries. For about 23% of Ontario’s population, ground sources are the main supply of water. This water can be contaminated by wastewater treatment infiltration basins, landfills, waste disposal into deep wells, spray irrigation, sludge use or disposal operations, septic tank systems and mine tailings.
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations. In the most common usage, it refers to the municipal wastewater that contains a broad spectrum of contaminants resulting from the mixing of wastewaters from different sources.
Sewage Treatment (More info here)
Sewage (or domestic wastewater) treatment incorporates physical, chemical and biological processes which treat and remove physical, chemical and biological contaminants from water following human use. The objective of the treatment is to produce both a clean wastestream (or treated effluent) suitable for discharge or reuse back into the environment, and a solid waste or sludge also suitable for proper disposal or reuse. This material is often inadvertently contaminated with toxic organic and inorganic compounds (e.g. heavy metals).
Sewage is generated by residences, institutions, and commercial and industrial establishments. It can be treated onsite at the point of which it is generated (e.g., septic tanks or onsite package plants), or collected and conveyed via a network of pipes and pump stations to a municipal treatment plant (see Sewerage and pipes and infrastructure). Efforts to collect, treat and discharge domestic wastewater are typically subject to local, state and federal regulations and standards (regulation and controls). Industrial sources of wastewater often require specialized treatment processes (- see Industrial wastewater treatment).
Typically, sewage treatment is achieved by the initial physical separation of solids from the raw wastewater stream followed by the progressive conversion of dissolved biological matter into a solid biological mass using indigenous, water-borne bacteria. Once the biological mass is separated or removed, the treated water may undergo additional disinfection via chemical or physical processes. This 'final effluent' can then be discharged or re-introduced back into a natural surface water body (stream, river or bay) or other environment (wetlands, golf courses, greenways, etc.). The segregated biological solids undergo additional treatment and neutralization prior to proper disposal or re-use.
These treatment processes are typically referred to as
for more information about the treatment process, click here.
Safe Drinking Water Act
Wikipedia information about Wastewater
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Wastewater".
Copyright © 2006, The Hill Engineering Group Inc.