The Water Recycling Process

All the water that is on Earth today is the same amount that was there yesterday and the same amount that will be here in the future. So when you brush your teeth every day, you could be, theoretically speaking, using the very same water that dinosaurs drank from millions of years ago. Talk about a case of dinosaur breath!

For 3 billion years, Earth has been using, cleaning and then reusing its water again and again. Water never wears out or breaks. It just gets dirty and needs to be cleaned. The ability of water to be used and reused is known as recycling.

Human beings moved from living as hunters and gatherers to putting down roots as farmers and then finally building civilizations. As these developments occurred, the disposal of sewage or wastewater became an important health issue. The ancient civilizations of Assyrians, Babylonians, Greeks and Romans all built extensive sewer systems to dispose of human waste. Stormwater sewers built thousands of years ago by the Romans are still in use today in parts of Europe.

By the beginning of the 20th Century, human wastes were removed from cities and towns through miles and miles of wastewater pipelines. However, the wastes were often not treated and were dumped into surrounding bodies of surface water. This practice caused the death of numerous plants and animals and greatly contributed to the spread of diseases such as cholera among human populations. Clearly, the solution was to clean up the waste and pollution before it entered a body of surface water.

Just like nature is able to clean dirty water and make it usable again, modern treatment facilities use similar processes to clean wastewater. The four major wastewater cleaning components are:

 

Water Recycling Process

  1. Pretreatment: Metal screens are used to remove large objects and chunks of debris when water passes through.
  2. Primary treatment: Gravity is used to cause solid matter to settle to the bottom of large basins.
  3. Secondary treatment: Microorganisms are added to digest any remaining pollutants. Air is also added to speed up digestion. After the microorganisms have "eaten," they settle to the bottom of large basins.
  4. Tertiary treatment: Remaining small solid particles are mixed with a chemical to form larger particles called floc. The floc is then trapped in filters containing anthracite coal and/or sand. Chlorine or another type of disinfectant is added to water to ensure that the water is safe before being released back to into the environment through a network of underground pipelines. The recycled water pipelines are separate from drinking water pipelines.

Now that the water has been reclaimed or recycled, it can be used for a variety of non-drinking water purposes. Recycled water is used to irrigate schools, parks, golf courses and other landscaped areas. It can also be used during the manufacturing process for oil refining, carpet dyeing and cement production.

Locally, West Basin Municipal Water District build the West Basin Water Recycling Facility to provide recycled water for irrigation and industrial uses at 210 South Bay sites. Highly treated recycled water from West Basin is also used a barrier to prevent seawater from mixing with valuable freshwater contained in the West Coast Basin Aquifer.

Recycled water is part of West Basin's overall strategy to reduce the amount of imported water to the South Bay. This strategy, the Integrated Resources Plan, combines water recycling, water education, water conservation, cooperative groundwater management and desalination efforts to increase water reliability within the region.

Nationally, government agencies such as the Environmental Protection Agency, U.S. Geological Survey and U.S. Bureau of Reclamation as well as professional associations such as the American Water Works Association and the Water Environment Federation are active in a variety of recycled water issues. Within California, government agencies such as the Department of Water Resources, Department of Health Services and Regional Water Quality Control Board as well as professional associations such as the Association of California Water Agencies and WateReuse Association of California are also heavily involved in recycled water issues. Locally in Southern California, environmental groups such as the Mono Lake Committee, Heal the Bay and Surfriders Foundation as well as government agencies such as the Sanitation Districts of Los Angeles County and West Basin are all actively involved in ensuring that recycled water used in communities throughout the South Bay is a reliable, high-quality alternative source of non-drinking water for irrigation and industrial use.

Using recycled water for non-drinking water purposes:

  • Reduces the need to import expensive water from environmentally sensitive watersheds in Northern California and the Colorado River.
  • Provides an alternative dependable water source that, during the next drought, will ease potential water shortages and loss of jobs.
  • Protects local drinking water aquifers from seawater intrusion.
  • Increases environmental protection by reducing the amount of treated wastewater released into the ocean.

- courtesy West Basin Municipal Water District