Rain Water Conservation

[Airbrush]

"Given the energy intensive nature of desalination, with associated economic and environmental costs, desalination is generally considered a last resort after water conservation. But this is changing as prices continue to fall."  Desalination - Wikipedia

Rain water harvesting could be a major source of fresh water.  If enough houses and buildings were designed with gutters that collect all the rain that lands on a roof, and all that runs off pavement, that water could be saved in big reservoirs attached to any house or building.  That water can be used for growing plants and all households needs.  Watering lawns should be discouraged but rather use drought-resistant landscaping.  The sewer system depends on rain water flushing the waste to the ocean, but much rain water could be skimmed off to be saved and used locally.

"One of the strategies in water conservation is rain water harvesting.^[8] Digging ponds, lakes, canals, expanding the water reservoir, and installing rain water catching ducts and filtration systems on homes are different methods of harvesting rain water. Many people in many countries keep clean containers so they can boil it and drink it, which is useful to supply water to the needy.^[8] Harvested and filtered rain water can be used for toilets, home gardening, lawn irrigation, and small scale agriculture."

Water conservation - Wikipedia

Edited May 9, 2022 by Airbrush

[beecee]

4 hours ago, Airbrush said:

 Harvested and filtered rain water can be used for toilets, home gardening, lawn irrigation, and small scale agriculture."

I live in the city, but still have a rain water tank outside for those purposes. 

[exchemist]

6 hours ago, Airbrush said:

"Given the energy intensive nature of desalination, with associated economic and environmental costs, desalination is generally considered a last resort after water conservation. But this is changing as prices continue to fall."  Desalination - Wikipedia

Rain water harvesting could be a major source of fresh water.  If enough houses and buildings were designed with gutters that collect all the rain that lands on a roof, and all that runs off pavement, that water could be saved in big reservoirs attached to any house or building.  That water can be used for growing plants and all households needs.  Watering lawns should be discouraged but rather use drought-resistant landscaping.  The sewer system depends on rain water flushing the waste to the ocean, but much rain water could be skimmed off to be saved and used locally.

"One of the strategies in water conservation is rain water harvesting.^[8] Digging ponds, lakes, canals, expanding the water reservoir, and installing rain water catching ducts and filtration systems on homes are different methods of harvesting rain water. Many people in many countries keep clean containers so they can boil it and drink it, which is useful to supply water to the needy.^[8] Harvested and filtered rain water can be used for toilets, home gardening, lawn irrigation, and small scale agriculture."

Water conservation - Wikipedia

This is not exactly news, though, is it? People have done this for millennia. What's the issue for discussion here? 

[swansont]

8 hours ago, Airbrush said:

water could be saved in big reservoirs attached to any house or building.

Where does the reservoir go in a city for multi-unit dwellings or business properties? (i.e. you don't have a yard for a barrel)

Quote

The sewer system depends on rain water flushing the waste to the ocean

Where? A lot of places treat the sewage rather than dump it in the ocean.

https://en.wikipedia.org/wiki/Sewage_treatment#By_country

[CharonY]

In addition, many areas that have a wastewater treatment plant also have separate storm drains systems. AFAIK, sewage is mostly moved by gravity (including lift stations) or pressurized pipes. In many (especially arid) areas relying on rain would not work well.

[Airbrush]

6 hours ago, exchemist said:

This is not exactly news, though, is it? People have done this for millennia. What's the issue for discussion here? 

What percentage of homes and businesses collect and use their rainwater runoff?  It has to become popular and wide spread or it doesn't help much.  I collect a little, but not enough.

3 hours ago, swansont said:

Where does the reservoir go in a city for multi-unit dwellings or business properties? (i.e. you don't have a yard for a barrel)

Where? A lot of places treat the sewage rather than dump it in the ocean.

https://en.wikipedia.org/wiki/Sewage_treatment#By_country

Yes, where do the multi-unit reservoirs go?  Maybe some engineer has an idea where it can go.  The last big rain we had in Socal, my barrel filled in an hour and hundreds of gallons ran off into the street.  And that was just me.

Yes, a lot of places treat sewage, but not all.  Many places in the world still dump in the ocean.

"In the U.S. sewage first goes to treatment facilities where it’s processed into liquid and solids.  After the liquid is cleaned (filtration and chlorine) it can be reintroduced into our rivers and oceans.

Modern treatment plants don’t allow actual fecal matter to enter our oceans, however, it’s not the case for all countries. Older infrastructure, overflows, and broken sewage lines can cause millions of gallons of untreated sewage to seep into rivers and oceans."

Does Sewage Go Into The Ocean (The Answer May Surprise You) (beachlifeexpert.com)

Edited May 9, 2022 by Airbrush

[exchemist]

17 minutes ago, Airbrush said:

What percentage of homes and businesses collect and use their rainwater runoff?  It has to become popular and wide spread or it doesn't help much.  I collect a little, but not enough.

 

I collect some in a water butt connected to a gutter downpipe, for watering calcifuge plants, that's all. But then I live in an area that is not short of water, as do many people. Statistics on who collects and who doesn't are only really relevant if they relate to areas that are short of water or projected to become so.

As for sewage, what we need here in the UK is an initiative to separate sewage from rainwater runoff. Sewage is processed in sewage farms, not discharged to the sea (unless there's a problem with the treatment plant, which happens too often). Adding the volume of rainwater runoff to it, as we have done since the Victorian sewers were built, just magnifies the volume that has to be treated. It's a thoroughly bad idea. We ought to be able to run rainwater into the rivers and process sewage alone in the treatment plants. 

 

[swansont]

1 hour ago, Airbrush said:

 

Yes, a lot of places treat sewage, but not all.  Many places in the world still dump in the ocean.

"In the U.S. sewage first goes to treatment facilities where it’s processed into liquid and solids.  After the liquid is cleaned (filtration and chlorine) it can be reintroduced into our rivers and oceans.

Modern treatment plants don’t allow actual fecal matter to enter our oceans, however, it’s not the case for all countries. Older infrastructure, overflows, and broken sewage lines can cause millions of gallons of untreated sewage to seep into rivers and oceans."

Does Sewage Go Into The Ocean (The Answer May Surprise You) (beachlifeexpert.com)

So what can countries that can't afford the infrastructure do to all of the sudden afford the infrastructure?

Broken or outdated systems still do not mean that "The sewer system depends on rain water flushing the waste to the ocean." This is just moving the goalposts. 

[Airbrush]

Nothing much will be done about saving rainwater until the price of water goes up.  I remember when my average cost per gallon of water was 1/2 cent per gallon.  Now, 20 years later, it is still only a penny a gallon.

[OldChemE]

Somewhat off topic-- but I find it interesting how the concentration of population (cities and such) by necessity makes topics like this important.  We are very rural, high desert, and do rainwater conservation and recycling without even giving it thought,  Our land is flat, unpaved, porous, and the soil is dry on the surface.  When it rains there is no stream for the water to flow into.  Instead, the water soaks into the ground fairly quickly (with some evaporation loss, of course).  This feeds our groundwater, and we pump it out with a well.  After we use it it goes into the septic system, from which it percolates back to the groundwater system.