Last modified on 12 November 2010, at 16:01

High School Earth Science/Protecting the Water Supply

Lesson ObjectivesEdit

  • Discuss how water is treated to eliminate harmful particles.
  • State what governments and international organizations can do to reduce water pollution.
  • Describe several ways water can be conserved.

Water TreatmentEdit

The goal of water treatment is to make water suitable for such uses as drinking water, medicine, agriculture, and industrial processes.

People living in developed countries suffer from few waterborne diseases and illness, because they have extensive water treatment systems to collect, treat, and redeliver clean water to their people. Many undeveloped nations have few or no water treatment facilities.

Water treatment is any process used to remove unwanted contaminants from water (Figure 21.22). Water treatment processes are designed to reduce harmful substances such as suspended solids, oxygen-demanding materials, dissolved inorganic compounds, and harmful bacteria. Ideally, water treatment produces both liquids and solid materials that are not harmful the natural environment.

Figure 21.22: Most wastewater treatment facilities separate contaminants from water by passing wastewater through a series of settlement containers. At each step, solids and particles are separated from water. Chemical and biological agents are also used to remove any remaining impurities.

Water can contain hundreds of contaminants. Not all treatment processes are able to remove all of these particles and not all treated water is pure enough to qualify as safe drinking water. Sewage treatment is any process that removes contaminants from sewage or wastewater. Water purification is any process used to produce drinking water for humans by removing contaminants from untreated water. Purification processes remove bacteria, algae, viruses, and fungi, unpleasant elements such as iron and sulphur, and man-made chemical pollutants.

The choice of treatment method used depends on the kind of wastewater being treated. Most wastewater is treated using a series of steps, increasingly purifying the water at each step. Treatment usually starts with separating solids from liquids. Water may then be filtered or treated with chlorine. With each subsequent step, the water has fewer contaminants and the effluent is increasingly pure.

Reducing Water PollutionEdit

How can people reduce water pollution? And who is responsible for doing it?

People have two ways to reduce any kind of pollution: We can prevent people from polluting water. And, we can use science to clean contaminants from water that is already polluted.

Governments can:

  • Pass laws to control pollution emissions from different sources, such as factories and agriculture.
  • Pass laws that require polluters to clean up water they pollute.
  • Provide money to build and run water treatment facilities (and fund research to improve water quality technology).
  • Educate the public, teach them how to prevent and clean up water pollution.
  • Enforce laws.

The United Nations and other international groups have established organizations to improve global water quality standards. Some international organizations provide developing nations with the technology and education to collect, treat, and distribute water. Another priority is educating the people in these countries about how they can help improve the quality of the water they use.

In the United States, legislators passed the Clean Water Act which gives the Environmental Protection Agency the authority to sets standards for water quality for industry, agriculture and domestic uses (Figure 21.23).

Figure 21.23: Scientists control water pollution by sampling the water and studying the pollutants are in the water.

One of the toughest problems is enforcement, catching anyone who is not following water regulations. Scientists are working to create methods to accurately track the source of water pollutants. Monitoring (tracking) methods allow the government to identify, catch and punish violators.

Who is responsible for reducing water pollution? Everyone who pollutes water is responsible for helping to clean it up. This includes individuals, communities, industries, and farmers.

Just a few of the things you can do to protect water quality include:

  • Find approved recycling or disposal facilities for motor oil and household chemicals so these substances do not end up in the water.
  • Use lawn, garden, and farm chemicals sparingly and wisely.
  • Repair automobile or boat engine leaks immediately.
  • Keep litter, pet waste, leaves, and grass clippings out of gutters and storm drains.

Controlling Ocean PollutionEdit

Figure 21.24: Many forms of marine pollution can be controlled by regulation such as the pumping of ballast water from ships.

Controlling seawater pollution and fresh water pollution are similar, but not exactly the same. We can try to prevent polluters from further spoiling the ocean and we can require polluters to clean up any pollution they cause. Government and international agencies can pass laws, provide funding, and enforce laws to prevent and clean up ocean pollution (Figure 21.24).

Several national and international agencies monitor and control ocean pollution. The agencies include the National Oceanic and Atmospheric Administration (NOAA), the Environmental Protection Agency, the Department of Agriculture as well as other federal and state agencies.

When runoff pollution does cause problems, NOAA scientists help track down the exact causes and find solutions. This organization is also one of many organizations trying to educate the public on ways to prevent ocean pollution.

Conserving WaterEdit

As human population growth continues, water conservation will become increasingly important globally (Figure 21.25). Yet, the methods to conserve water are likely to differ between developing nations and developed countries.

Figure 21.25: Low flow showerheads reduce the amount water used during showers.

For example, some people in undeveloped countries use so little water, that they may not gain much water by reducing their personal use. Meanwhile, large quantities of water can be conserved in the United States by finding ways to stop over-consumption of water.

At Earth Summit 2002 many governments approved a Plan of Action to address the scarcity of water and safe drinking water in developing countries. One goal of this plan is to cut in half, the number of people without access to safe drinking water by 2015.

Developed countries have many options to reduce water consumption. A farmer can cut water consumption drastically by using more efficient irrigation methods. People also have many opportunities to reduce our personal and household water demand with such measures as low flow shower heads, toilets that use less water, and drip irrigation to water lawns.

During prolonged droughts and other water shortages, some communities ration water use and prohibit such water intensive uses as watering lawns during the day and hosing down sidewalks. Often legislation is needed to provide incentives for individuals to reduce their water consumption.

Lesson SummaryEdit

  • Many technologies are available to conserve water as well as to prevent and treat water pollution. Yet, most undeveloped countries cannot afford the technology they need to collect, treat and distribute water to their people.
  • Developing countries may be able to afford water treatment systems, but people still need incentives to use conservation steps.

Review QuestionsEdit

  1. What is the purpose of water treatment and purification?
  2. How can governments and international organizations help to reduce water pollution?
  3. Name three things that a person could do to reduce pollution?
  4. Name three ways that you could reduce your personal water use.

VocabularyEdit

sewage treatment
Any process that removes contaminants from sewage or wastewater.
water purification
Any process used to produce safe drinking water by removing contaminants.

Points to ConsiderEdit

  • Who is responsible for controlling water pollution?
  • What can governments and international organizations do to control pollution?
  • It is usually cheaper to dump polluted water without spending money to treat and purify the water. What incentives would convince industry to control water pollution?


Water Pollution · Human Actions and the Atmosphere