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Egypt has managed to plant trees in the desert using wastewater

al-monitor.com

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Re: Egypt has managed to plant trees in the desert using wastewater

#2
It's not clear to me what the source of water is relative to the size of the forest, because IIUC, in dry regions like Egypt (and California, Israel, etc), unless you use drip-irrigation with targeted crops (which won't grow a forest), agriculture requires a huge amount of water compared to domestic water consumption, so the wastewater stream from the latter intuitively can't be nearly enough to support a forest.

Perhaps they are drip irrigating the entire floor of the artificial forest to minimize evaporative losses? The paper linked in the article [1] doesn't really explain how they are doing this.

EDIT: this article [2] explains the system in a bit more detail. For a sense of the scale of forest vs the wastewater supply, it's a city of 400K people whose wastewater is supporting a .78 square mile "forest". So it's really more like a large park. It's a great demonstration nonetheless, especially if it can be a productive source of food for the city.

1. http://www.fao.org/forestry/35800-094f4eedb0c86a4a33be1a3d90...

2. https://www.intelligentliving.co/egyptian-desert-forest-recy...

Re: Egypt has managed to plant trees in the desert using wastewater

#4
post #2

It's not clear to me what the source of water is relative to the size of the forest, because IIUC, in dry regions like Egypt (and California, Israel, etc), unless you use drip-irrigation with targeted crops (which won't grow a forest), agriculture requires a huge amount of water compared to domestic water consumption, so the wastewater stream from the latter intuitively can't be nearly enough to support a forest. Per…

That's the current forest that was started in 98. The one that they're starting now is 100 million hectares (1 million sq km).

Re: Egypt has managed to plant trees in the desert using wastewater

#5
post #3

Less than 500 acres planted using sewege water from cities. The rest (planting millions of acres of forest) is just a wishlist and the article is short on details.

To be fair, it was a proof of concept to see if it was possible. They did prove that it is possible. The rest of the details probably haven't been sorted out yet for how they plan to scale it. A terraforming project can easily take many decades or even a century to complete. So I think it is encouraging to see them starting and/or attempting this to benefit the generations to come.

Re: Egypt has managed to plant trees in the desert using wastewater

#6
post #3

Less than 500 acres planted using sewege water from cities. The rest (planting millions of acres of forest) is just a wishlist and the article is short on details.

Israel already gets the majority of its water, including for irrigation, from desalination.[1] They achieve this through a combination of conserving and recycling water as well as very targeted irrigation of crops, along with new technology such as the Sorek desal plant. The second generation may be up and running by 2023 [2].

There's an interesting paper [3] about building 40,000 Sorek style plants to sequester excess water in arid areas and avoid problems with sea level rise. Without any savings at scale, this would be around 20 trillion dollars, but that's clearly cheaper than building infrastructure to protect coasts around the world, with the side benefit of creating jobs and food in areas that are in the most need.

I've been working (in the script-writing sense) on a narrative around EarthStations -- molten salt solar towers powering desal plants and green tech manufacturing, surrounded by highly efficient farms, and further out in the ring, forests that eat the desert. Since they are located on coasts, all the infrastructure can be delivered by ships, and all the goods created easily shipped out once they are up and running.

One big technical problem is what to do with the brine -- I'm not sure how much could go into molten salt heat storage. But they could serve as an engine to keep sea levels stable.

This is a longwinded way of saying I think the project in Egypt is a good example of the terraforming we need to be doing instead of dreaming about for a planet like Mars. Even though it is small scale, turning deserts into forests is pretty impressive, and something we need to do learn how to do well to fight climate change.

[1] https://www.scientificamerican.com/article/israel-proves-the...

[2] https://en.globes.co.il/en/article-ide-wins-sorek-2-desalina...

[3] https://f1000research.com/articles/5-889

Re: Egypt has managed to plant trees in the desert using wastewater

#7
My idea would be to flood lower than sea level deserts with ocean water and then start a mangrove forest. (They thrive in salt water)

Of course the evaporation might raise the salinity above what they could handle. Perhaps a monthly flush out somehow?

Re: Egypt has managed to plant trees in the desert using wastewater

#8
Architecture has had a moment where it was proposing green rooftops and nature-integrations for large developments. Where did that disappear to? There aren't even any recent nominations of projects which beautifully and functionally integrate green spaces into their construction.

Re: Egypt has managed to plant trees in the desert using wastewater

#9
post #4
post #2

It's not clear to me what the source of water is relative to the size of the forest, because IIUC, in dry regions like Egypt (and California, Israel, etc), unless you use drip-irrigation with targeted crops (which won't grow a forest), agriculture requires a huge amount of water compared to domestic water consumption, so the wastewater stream from the latter intuitively can't be nearly enough to support a forest. Per…

That's the current forest that was started in 98. The one that they're starting now is 100 million hectares (1 million sq km).

That is 380 times larger. Unless they are massively underutilizing the current wastewater stream, they need to multiply the irrigation water use efficiency that much, unless they think of forest is going to alter weather systems in such a way that brings rain to the area.

Re: Egypt has managed to plant trees in the desert using wastewater

#10
This says the humidity of the Sahara desert is 25%. I wonder if you could devise some kind of system to collect water from the air? (Taking advantage of the big difference in day and night temperatures)

https://saharadesertinfo.weebly.com/humidity.html

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