Reclaimed Wastewater

Science Center Objects

Thirsty? How about a refreshing cup of reclaimed wastewater? No, we're kidding. You probably don't drink much reclaimed wastewater (although some people do - see below)! But reclaimed wastewater has many uses, with more promise of usage in the future.

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Reclaimed Wastewater

Vials of water, raw sewage to reclaimed water, showing purity.

Sequence of reclamation from left: raw sewage, plant effluent, and finally reclaimed water (after several treatment steps). (Credit: Wikipedia)

You may have seen a picture of the mayor of a town getting ready to drink a cup of reclaimed wastewater....water that has been treated by a sewage-treatment plant till it is so pure that it (could be) consumed. Naturally, people will not be inclined to drink reclaimed water, even if it is indeed pure enough, but there are many other uses for reclaimed wastewater.

With the scarcity of water in some parts of the U.S. and with water conservation being so important nowadays, the reuse of treated wastewater is becoming more important. No, you don't have to worry about your drinking water at home coming right from a sewage-treatment plant (although a successful test of this has been done!!), but treated wastewater is being used for certain purposes throughout the country.

The use of reclaimed wastewater helps people in two ways:

  1. Reclaimed water can supply needed water for some purposes
  2. Reclaimed wastewater frees up fresh water that can be used somewhere else, such as for drinking water

California is a good place to go to see how reclaimed wastewater is being used. The East Bay Municipal Utility District has a working water reclamation project that benefits the community in these ways:

  • Conserves drinking water
  • Reduces pollution into San Francisco Bay
  • Provides water for irrigation and industrial purposes

Their project results in a savings of about 5.5 billion gallons per year. Eventually the project will save enough water to provide drinking water to 83,000 households.

 

If it's good enough for astronauts...

Astronauts about the space station drinking recycled urine.

Astronauts abord the International Space Station drink reclaimed urine. (Credit: NASA)

In outer space, as on the International Space Station, water is at a premium and not a drop is to be wasted. Astronauts aboard the station must drink recycled water. Water from humidity in the air is condensed and used as drinking water, but American astronauts also drink recycled urine! You can imagine the urine, which is of course almost all water, would go through a rigorous purification process, but this just shows if the need exists, that the same water can serve valuable purposes over and over again.

 

Uses of reclaimed wastewater

So, what exactly is reclaimed wastewater used for? A lot of it goes toward watering golf courses and landscaping alongside public roads, etc. Some industries, such as power-generation plants can use reclaimed wastewater. A lot of water is needed to cool power-generation equipment, and using wastewater for this purposes means that the facility won't have to use higher-quality water that is best used somewhere else.

Most of the uses of water reclamation are non potable uses such as washing cars, flushing toilets, cooling water for power plants, concrete mixing, artificial lakes, irrigation for golf courses and public parks, and for hydraulic fracturing. Where applicable, systems run a dual piping system to keep the recycled water separate from the potable water.

URBAN USES

Irrigation of public parks, sporting facilities, private gardens, roadsides; Street cleaning; Fire protection systems; Vehicle washing; Toilet flushing; Air conditioners; Dust control.

AGRICULTURAL USES

Food crops not commercially processed; Food crops commercially processed; Pasture for milking animals; Fodder; Fiber; Seed crops; Ornamental flowers; Orchards; Hydroponic culture; Aquaculture; Greenhouses; Viticulture; Industrial uses; Processing water; Cooling water; Recirculating cooling towers; Washdown water; Washing aggregate; Making concrete; Soil compaction; Dust control.

RECREATIONAL USES

Golf course irrigation; Recreational impoundments with/without public access (e.g. fishing, boating, bathing); Aesthetic impoundments without public access; Snowmaking.

ENVIRONMENTAL USES

Aquifer recharge; Wetlands; Marshes; Stream augmentation; Wildlife habitat; Silviculture.

POTABLE (DRINKABLE) USES

Aquifer recharge for drinking water use; Augmentation of surface drinking water supplies; Treatment until drinking water quality.