Using Saltwater in Toilets

[KrallSpace29]

The title is pretty self explanatory. Seems like it may be a good idea to use the vast amounts of saltwater in the ocean for eliminating waste to the treatment plants, or maybe waste treatment could be looked at a little differently. 

 

Or even to have the option to take a saltwater shower sometimes might be a good, even saving fresh water usage even more. 

 

I wouldn't feel so bad pushing the flush lever if I knew the water were saltwater.

[Genady]

6 minutes ago, KrallSpace29 said:

eliminating waste to the treatment plants

It will not.

 

7 minutes ago, KrallSpace29 said:

to take a saltwater shower sometimes might be a good

No, it is not.

[exchemist]

9 minutes ago, KrallSpace29 said:

The title is pretty self explanatory. Seems like it may be a good idea to use the vast amounts of saltwater in the ocean for eliminating waste to the treatment plants, or maybe waste treatment could be looked at a little differently. 

 

Or even to have the option to take a saltwater shower sometimes might be a good, even saving fresh water usage even more. 

 

I wouldn't feel so bad pushing the flush lever if I knew the water were saltwater.

Except it would mean doubling the pipe network and would create a lot of extra costs for locations far from the ocean. And the waste water would still need treatment of course. So in fact, not such a great idea when you stop and think about it.

Edited August 22, 2023 by exchemist

[Genady]

1 minute ago, exchemist said:

would create a lot of extra costs for locations far from the ocean

and close to the ocean as well.

And all that just for flashing toilet?

[iNow]

There's a kernel of a good idea here, though. We need to massively invest in global desalination and transport of the fresh water which results to address the real issues of drought and crop failure which will drive suffering, poverty, and mass migration for many generations to come.

Desalination can help with a lot of the risks we and our children are about to face, but it requires huge investment and policy support to achieve. 

[Genady]

2 minutes ago, iNow said:

There's a kernel of a good idea here, though. We need to massively invest in global desalination and transport of the fresh water which results to address the real issues of drought and crop failure which will drive suffering, poverty, and mass migration for many generations to come.

Desalination can help with a lot of the risks we and our children are about to face, but it requires huge investment and policy support to achieve. 

Desalinated water, by reverse osmosis, is the fresh water this entire island lives on.

[Steve81]

28 minutes ago, iNow said:

There's a kernel of a good idea here, though. We need to massively invest in global desalination and transport of the fresh water which results to address the real issues of drought and crop failure which will drive suffering, poverty, and mass migration for many generations to come.

Desalination can help with a lot of the risks we and our children are about to face, but it requires huge investment and policy support to achieve. 

Seems like with all the waste heat associated with thermal power plants, there would be opportunities to use that energy for such a purpose via distillation.

Edited August 22, 2023 by Steve81

[zapatos]

Wonder what all that salt water is going to do to the metal components it comes in contact with. And we've now given the treatment plants the additional responsibility of desalination or risk killing freshwater plants and fish or fouling groundwater when the treated water is discharged.

[Sensei]

After using salt water, sediment will build up in the toilet and pipes.

https://www.google.com/search?q=saltwater+sediments+in+pipes

Edited August 22, 2023 by Sensei

[John Cuthber]

9 minutes ago, Sensei said:

After using salt water, sediment will build up in the toilet and pipes.

Why?

Anyway, this would be a good plan in very limited circumstances.

If you had, for example, a small island with little or no infrastructure and you were introducing a sewerage system for a small number of inhabitants then maybe it would be acceptable having a waste pipe that led out to sea with no treatment.
If there was also a shortage of fresh water on the island such that pumping sea water was less "expensive" than desalinating it, then maybe it would be worth installing a separate sea water feed pipe to the village just for flushing toilets.

But in almost all other situations, it's not going to work.

(I'm about 300 feet above sea level, in the rather rainy North of England...)



Having said all that, using "grey" water to flush the toilet is an excellent idea.

Edited August 22, 2023 by John Cuthber

[Genady]

In order not to waste septic freshwater, many households here use it, appropriately filtered, for irrigation.

[zapatos]

[exchemist]

48 minutes ago, Steve81 said:

Seems like with all the waste heat associated with thermal power plants, there would be opportunities to use that energy for such a purpose via distillation.

That's how Jebel Ali desalination plant worked, when I lived in Dubai in the 1980s, using waste heat from Jebel Ali power station. 

Edited August 22, 2023 by exchemist

[sethoflagos]

1 hour ago, KrallSpace29 said:

Seems like it may be a good idea to use the vast amounts of saltwater in the ocean for eliminating waste to the treatment plants, or maybe waste treatment could be looked at a little differently. 

Or even to have the option to take a saltwater shower sometimes might be a good, even saving fresh water usage even more.

Based on personal experience, the major technical challenge to pumped sea water systems is that it is considerably more nutritious than fresh water. Large channels rapidly attract colonies of mussels and oysters etc, and small channels (eg cistern fill valves, filters) get blocked by salps.

Not insurmountable problems, but expensive to solve.

Anding nitrogenous waste to the mix will escalate these biological issues even further.

Edited August 22, 2023 by sethoflagos
sp

[Steve81]

32 minutes ago, zapatos said:

Wonder what all that salt water is going to do to the metal components it comes in contact with. And we've now given the treatment plants the additional responsibility of desalination or risk killing freshwater plants and fish or fouling groundwater when the treated water is discharged.

I presume you’re responding to me, but it’s not clear since you didn’t quote me.

The only major metal component salt water would come into contact with is the boiler, AFAIK. Clean it out occasionally, and maybe even sell the sea salt. 

Edited August 22, 2023 by Steve81

[zapatos]

1 minute ago, Steve81 said:

The only component salt water would come into contact with is the boiler.

Pipes? Toilet tank mechanism? Pumps? Metal components at the sewage plant? 

[studiot]

Isn't all this talk of boilers off topic ?

After all how many toilets have boilers ?

 

I remember most work vessels in the 70s and 80s in the gulf using salt water to flush the toilets.

 

Readers, may have come across the fictional character, modelled on Nelson, called Hornblower, treating himself to a daily sluicing in sea water (hand) pumped by the ratings on his ships, even in the Atlantic winter.

Edited August 22, 2023 by studiot

[Steve81]

38 minutes ago, zapatos said:

Pipes? Toilet tank mechanism? Pumps? Metal components at the sewage plant? 

I’m talking about the power plant application from my prior post, FYI. Sorry for the confusion.

40 minutes ago, studiot said:

Isn't all this talk of boilers off topic ?

After all how many toilets have boilers ?

It is, though tangentially relates. Was just replying to iNow’s astute observation that we mostly need more fresh water.

[Endy0816]

Submarine toilets use sea water. The top two green valve handles are for filling and the bottom lever handle allows flushing to a tank below.

 

The resulting sewage isn't ever treated though, rather it flows to the tank and then eventually blown or pumped overboard(when at sea).

Suspect the salt mixed in with the sewage would pose problems for your typical water treatment plant. Grey water or rainwater is a very viable alternative option however.

 

 

 

Edited August 22, 2023 by Endy0816

[Sensei]

Astronauts use their pee to "flush the toilet", and to drink, and yet they live *) That's true "no waste!"..

Maybe it's time to use it in skyscrapers?

 

*) actually, everyone in this world uses e.g. dinosaur piss water..

 

[zapatos]

3 hours ago, Steve81 said:

I’m talking about the power plant application from my prior post, FYI. Sorry for the confusion.

My fault. I didn't re-read your post first to understand why you responded the way you did.

[KrallSpace29]

5 hours ago, zapatos said:

Wonder what all that salt water is going to do to the metal components it comes in contact with. And we've now given the treatment plants the additional responsibility of desalination or risk killing freshwater plants and fish or fouling groundwater when the treated water is discharged.

You could probably run something through the pipes that would make them more applied to the application. I was wondering the same thing. Maybe could lead to good jobs that we need. 

2 hours ago, Endy0816 said:

Submarine toilets use sea water. The top two green valve handles are for filling and the bottom lever handle allows flushing to a tank below.

 

The resulting sewage isn't ever treated though, rather it flows to the tank and then eventually blown or pumped overboard(when at sea).

Suspect the salt mixed in with the sewage would pose problems for your typical water treatment plant. Grey water or rainwater is a very viable alternative option however.

Cool to know. Thanks for the pic very interesting.

 

 

 

4 hours ago, Steve81 said:

I’m talking about the power plant application from my prior post, FYI. Sorry for the confusion.

It is, though tangentially relates. Was just replying to iNow’s astute observation that we mostly need more fresh water.

How many toilets have boilers hahahah

[npts2020]

12 hours ago, Steve81 said:

Seems like with all the waste heat associated with thermal power plants, there would be opportunities to use that energy for such a purpose via distillation

This is how most ships get their fresh water. They also use seawater for flushing commodes.

 

[Steve81]

56 minutes ago, npts2020 said:

This is how most ships get their fresh water. They also use seawater for flushing commodes.

Depends on the ship. A lot of vessels rely on massive diesel engines, vs steam boilers driving geared turbines these days. Outside of nuclear powered ships, I believe gas turbines are pretty popular in the navy due to their power to weight ratio.

https://www.cruisehive.com/how-do-cruise-ships-get-fresh-water/88883

Quote

Most cruise lines use either reverse osmosis processes or steam evaporation to desalinate water (remove the salt content) before adding chlorine and minerals to make it safe for consumption. This method is the same for home filtration systems, only on a larger scale.

https://www.globalsecurity.org/military/systems/ship/ddg-51-upgrade.htm
 

Quote

The major Smart Ship technologies include:

• Reverse-osmosis desalination plants: Creates more fresh water for the crew, which means no more short showers. Started with DDG 64 Carney.

Edited August 23, 2023 by Steve81

[npts2020]

28 minutes ago, Steve81 said:

A lot of vessels rely on massive diesel engines, vs steam boilers these days. Outside of nuclear powered ships, I believe gas turbines are pretty popular in the navy due to their power to weight ratio. 

Very few large ocean going vessels are not steam powered and the vast majority that aren't are military. The reason being that most of the relative advantages of gas turbines (quick start up, size, no steam etc.) are not as relevant to commercial ships as the fact that steam turbines are generally quite a bit more efficient.

Edited August 23, 2023 by npts2020