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Hydroponics

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PSA: The condensate from your dryer is distilled water (slrpnk.net)
submitted 5 days ago by Guenther_Amanita@slrpnk.net to c/hydroponics@slrpnk.net
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It's the first time I own a dryer. When I poured out the water it has collected (a few liters per run) I quickly tested the EC and pH and found out, that it is almost identical to the one made by my reverse osmosis filter!
No wonder, since the dryer is basically just a big distillation machine.

Thats super neat. It will save me a lot of work filtering tap water.

I will collect it from now on and use it for watering my plants.

Why does it matter?

Plants really don't like tap water. Even in a country like mine, where no chlorine/ fluoride/ whatever is added, the dissolved minerals cause trouble. They will build up over time and make nutrients unavailable, even if you adjust the pH.

The buildup and nutrient lockout will harm the plants a lot in the long term, and you will have way more trouble checking and correcting EC and pH.

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[–] Arcanepotato@crazypeople.online 41 points 5 days ago (2 children)

Comrade, it is not distilled water and neither is your RO.

Distilling separates fractions in the liquid by boiling point. That's why it's not just boiling a pot of water and catching all the steam. You need to have some sort of idea of what you are separating and ensure you are collecting the distillate at the correct temperature (based on the atmospheric pressure). RO is - in an extremely simplified description - a filter, where particles that are small/soluble enough will pass through the membrane if sufficient pressure is applied.

Distilled water will have zero conductivity, RO will have some.

As an aside because I am insufferable: your meter says TDS but it's measuring conductivity. They are often used interchangeably because TDS is a massive pain to test at home. If you are always measuring the same thing, it's fine to use conductivity as a surrogate, but you can't compare the conductivity of sugar water to salt water and assume you have a good idea of the TDS.

I won't venture to comment about its use on plants but to folks asking about drinking it in the comments, please don't. Even if it was distilled it's hanging out in an environment full of airborne life and wouldn't remain sterile for long.

(Credentials? I got a D in mass transfer 20 years ago but I still somehow manage to work as an engineer and do a lot of lab work too. But nothing I've said isn't readily verifiable)

[–] Guenther_Amanita@slrpnk.net 4 points 4 days ago (3 children)

Distilling separates fractions in the liquid by boiling point.

True, but it also includes the step with the condensation collumn and collection of the condensate. Boiling isn't linear, it can also turn into vapor at room temperature, especially with air movement.

Distilled water will have zero conductivity,

Not exactly. Gases, particularly CO2, can dissolve in it, and form carbonic acid for example. That's why it doesn't have a pH of 7, but 5-6ish.

As an aside because I am insufferable

Dude, stop saying that. That's rude to yourself! πŸ€—

You're just telling me concerns you have, not more. That's great. I like discussions and discourse, this is why we're here! And this is how people get smarter.

used interchangeably because TDS is a massive pain to test at home. If you are always measuring the same thing, it's fine to use conductivity as a surrogate, but you can't compare the conductivity of sugar water to salt water and assume you have a good idea of the TDS.

AFAIK the TDS is the TDS700 to be precise, which is for measuring nitrogen or something. It's a really shitty and inaccurate unit, which is why the EC is the preferred measurement for many hydro growers, including me.

What you're saying is that the dissolved/ dispersed things aren't detectable by condictivity, did I understand that correctly?

If so, then there have to be visible particles. I will do further experiments and boil some off to see if there are residues forming.

I won't venture to comment about its use on plants but to folks asking about drinking it in the comments, please don't. Even if it was distilled it's hanging out in an environment full of airborne life and wouldn't remain sterile for long.

I personally just treat it just as rainwater. Never ever would I drink something of it, and in case of rainwater, there's some visible debris floating around. In the condensate maybe too, we'll see!

(Credentials: chemistry profession)

[–] Cort@lemmy.world 5 points 4 days ago (1 children)

I'd be concerned about lint or micro plastic nylon (etc.) fibers in there. I doubt the lint filter is collecting 100% of the fibers before the warm moist air gets blown over the evaporator/condenser coils where condensate is collected.

[–] Guenther_Amanita@slrpnk.net 3 points 4 days ago

Yep, seems like it. I just looked at it closer in a glass beaker and saw lots of floaters around.

I still think most of it is cotton fibres, and even if it's microplastic, it is mostly inert and plants don't care much about it. I flush out my substrate every few months anyway, and not use it for food contact plants.

[–] Arcanepotato@crazypeople.online 2 points 4 days ago* (last edited 4 days ago)

Not exactly. Gases, particularly CO2, can dissolve in it, and form carbonic acid for example. That's why it doesn't have a pH of 7, but 5-6ish.

Fair - most of my distillation experience is not on water so I goofed in this fact (oversimplified)

AFAIK the TDS is the TDS700 to be precise, which is for measuring nitrogen or something. It's a really shitty and inaccurate unit, which is why the EC is the preferred measurement for many hydro growers, including me.

I think I'm missing some jargon.

TDS700? This is the method I am familiar with for TDS: https://edgeanalytical.com/wp-content/uploads/Waste_SM2540.pdf

Measuring nitrogen is a massive fucking pain with gross reagents but I suspect the nitrogen I work with is a lot different than nutrient mixes in hydro lol. Anything that needs a digestion step gets shipped to a Real lab.

I guess using conductivity for nitrogen is more about assuming the nutrient is "pure" but in different concentrations so you are just trying to see how dilute or concentrated it is based on the conductivity. I suppose that means it's it's a surrogate measurement not a direct measurement, which is why EC would be better than an actual TDS for that.

What you're saying is that the dissolved/ dispersed things aren't detectable by condictivity, did I understand that correctly?

If so, then there have to be visible particles. I will do further experiments and boil some off to see if there are residues forming.

Yes, but specifically that there are dissolved things that are not detectable by conductivity. No conductivity doesn't mean the solids must be non-dissolved. Not all things dissolve by breaking into ions. And not all ions give the same conductivity.

I misunderstood what you use the conductivity for - if it's to tell the strength of a known composition of unknown dilution, that's a pretty straight forward correlation.

Take for example the use of EC for TDS in drinking water, as described here: https://health.canada.ca/publications/healthy-living-vie-saine/water-dissolved-solids-matieres-dissoutes-eau/alt/water-dissolved-solids-matieres-dissoutes-eau-eng.pdf

The method most commonly used for the analysis of TDS in water supplies is the measurement of specific conductivity with a conductivity probe that detects the presence of ions in water. Conductivity measurements are converted to TDS values by a factor that varies with the type of water.(18,19)

[–] figjam@midwest.social 2 points 4 days ago

How do I use this information to make fireworks or booze?

[–] acockworkorange@mander.xyz 29 points 5 days ago (1 children)

It's mostly sweat and microbial growth. It's fine for plants, but don't use for anything else.

[–] neidu3@sh.itjust.works 13 points 5 days ago* (last edited 5 days ago) (1 children)

It's MY dryer, you can't tell me not to drink the condensate that's been sitting over the weekend!

[–] acockworkorange@mander.xyz 9 points 5 days ago

You're correct, my bad.

[–] CameronDev@programming.dev 22 points 5 days ago* (last edited 5 days ago) (2 children)

Don't drink it though, the our drier tub likes to grow pink ~~mold~~ bacteria.

Edit: fixed inaccuracies.

[–] budget_biochemist@slrpnk.net 28 points 5 days ago* (last edited 5 days ago) (1 children)

Living up to my username: Pink mold isn't an actual mold, it's usually a growth of a common airborne bacteria, Serratia marcescens. It's not particularly dangerous but can cause urinary tract, wound, skin and lung infections in immunocompromised people.

Condensate from home driers, air cons, dehumidifiers (etc) is not sterile or potable, it gets lots of airborne bacterial and fungal spores in it.

[–] CameronDev@programming.dev 7 points 5 days ago (1 children)

Interesting, thanks! Is drinking a film of it okay? I assumed not, but I am immunocompromised, so I'm happy to play it safe.

[–] budget_biochemist@slrpnk.net 3 points 4 days ago

I would definitely avoid drinking it - condensate from home dehumidifiers (etc) collects lots of spores and dust floating around in the air.

[–] Guenther_Amanita@slrpnk.net 4 points 4 days ago

Of course not. Only for plants. Thanks for the warning tho!

[–] Albbi@lemmy.ca 13 points 5 days ago (3 children)

I'm in Canada and our dryers are basically ovens that spin the clothes and the moisture is exhausted out of the house. How do your dryers work? I've never had water buildup anywhere with my dryer so I very curious.

[–] cybervseas@lemmy.world 11 points 5 days ago (1 children)

Some dryers are basically dehumidifiers+heaters, so they will collect and drain out the water from the clothes. This can be far more efficient than using resistive electric heating alone. And also means you don’t need a vent for your dryer so it can go in a tight space/closet. https://www.energystar.gov/products/clothes_dryers/heat-pump-dryer

[–] Albbi@lemmy.ca 9 points 5 days ago (1 children)

I love how in Europe things are more efficient due to needing to figure out how to fit things into smaller spaces. Thanks for the info!

[–] manualoverride@lemmy.world 5 points 4 days ago

It’s mainly down to our strict energy efficiency regulations, when shopping for a drier (which is already rare in Europe) they stick a big red flag and an β€œF” on the non efficient ones, and a green flag with β€œA+++” on the most efficient heat pump versions. There is also lots of data which need to be provided at point of sale and in advertising regarding the cost to run loads on various programs that make choosing an energy efficient model make sense.

[–] Guenther_Amanita@slrpnk.net 8 points 4 days ago

This is one of the newest generation heat pump dryers. Very energy efficient, since we in Germany desperately need exactly that...

It basically heats up air at one end, blows it around internally all the time, and then on the other end is a cool trap that removes all moisture from the warm air.

Said water is collected in a drawer-container and supposed to be discarded.

[–] Jarix@lemmy.world 6 points 5 days ago* (last edited 5 days ago) (1 children)

I'm also in Canada. Moved into an apartment and the dryer here is a condensor type. First time I had even seen one

It fucking sucks and takes twice as long to dry things

[–] whyNotSquirrel@sh.itjust.works 4 points 4 days ago (1 children)

but it's using much less energy as it's keeping the heat inside the house

[–] Jarix@lemmy.world 1 points 4 days ago (3 children)

Yeah no, it has to be on 2x as long everytime I use it. I don't give a shit if it uses more energy if that means I can spend 3 hours doing laundry and not 6.

Any savings are lost when the machine has to be on and working for twice as long

[–] whyNotSquirrel@sh.itjust.works 3 points 4 days ago

I have the feeling that you have a shit dryer πŸ˜…

It's not supposed to take that long, is it a heat pump?

[–] BillBurBaggins@lemmy.world 3 points 4 days ago (2 children)

  1. That makes no sense because if it's on for twice as long but uses less than half the watts then it doesn't lose any savings does it.

  2. You sit and watch the machine when it's on? Do you do the same thing with your dishwasher? Mine takes 5 hours but if it took 20 it literally wouldn't be an issue

[–] manualoverride@lemmy.world 2 points 4 days ago (1 children)

Heat pump driers use a bit of electricity to get up to temperature then a tiny amount to run the compressor and keep the heat topped up thought the cycle, they can take longer for some fibres (ones they have high resistance to airflow and also like to hold on to water) but they use far less energy to do that. The amount of energy used is not consistent through the wash.

Some loads my machine takes just over 1kWh (25p) to dry, maybe 2.5 hours, other loads take 30mins and 0.3kWh. (~8p)

[–] BillBurBaggins@lemmy.world 2 points 4 days ago

If this is supposed to be some kind of contradiction to me saying watts, then obviously you need to integrate it over time and arrive at the total used. It was just an example of how something could take longer but use less in total, not a detailed description of how a drier works. But thanks anyway

[–] Jarix@lemmy.world 1 points 4 days ago* (last edited 4 days ago) (1 children)

My electricity bill is much higher because I have to do multiple loads that used to be able to do in one. I don't care if the machine is technically more efficient if it takes a considerable amount more time to do the same amount of laundry. (My electricity is generated by hydro electric and without oil and gas and coal so efficiency isn't a big concern of mine.)

A task that should take 2.5 hours takes over 5 hours. It's not at all like a dishwasher and you can damn well understand if your dishwasher sucked so bad you had to do multiple loads it isn't as simple as starting it and forgetting it. Also you never have to unload your dishwasher each load to put them into a dish dryer, so that's an incredibly shitty and useless comparison. Nor do your dishes need to be folded for that matter.

I do other chores when I'm waiting between loads like a normal person. What the hell are you trying to say?

[–] BillBurBaggins@lemmy.world 1 points 4 days ago

Well ok but that's not really what you said. So yes I can't understand because you are bad at communicating

[–] Dogyote@slrpnk.net 1 points 4 days ago

You don't need to sit and watch it dry

[–] froh42@lemmy.world 3 points 4 days ago* (last edited 4 days ago)

Please be aware that that water can contain a lot of particles out of the clothes. It's better with a heat pump dryer as that has a better air filter to protect the condenser.

Also I recently fought some smell in my dryer by first spraying some diluted isopropyl on the condenser and then letting it dry out completely before closing up the maintenance hatch again.

I do believe bacteria can grow in the humid part where condensate is being collected - for a heat pump dryer even more so due to being warm but not hot.

When my daughter washes she's using fabric softener when washing - and I can smell that in the water collector after she uses the dryer. So the softeners perfume definitely is in the condensate.

But yes, I use it for plants, too. But (due to the particles) never in the clothes iron.

[–] BagOfHeavyStones@piefed.social 4 points 5 days ago (3 children)

If you put it though one of those water filter jugs from a shop, would it then be drinkable?

[–] WhiteOakBayou@lemmy.world 6 points 5 days ago

If you mean a filter pitcher then no. If you mean a bleach jug with that you dumped out and got pretty empty then yes. I haven't seen a passive filter for microorganisms at a regular store. They usually require some force like a hand pump for the portable ceramic filters or your lungs for the straw kind. Passive filters that I have seen and shopped for will get out some minerals/metals, chorine, plastic bits but not bacteria.

[–] whyNotSquirrel@sh.itjust.works 2 points 4 days ago (1 children)

why would you drink water with no minerals?

[–] Guenther_Amanita@slrpnk.net 2 points 4 days ago* (last edited 4 days ago)

I rarely drink tea (green/ black), but when I do, I brew it with RO water. The calcium in my very hard water causes gunk to form in my cup after a few minutes, soft one doesn't.

But I wouldn't drink the dryer piss water anytime in my life, that's disgusting!