8 ms·

Airports Had to Deal With Over 2B Litres of Airplane Toilet Waste in 2019

markus_zhang 5y ago
I wonder if it has enough liquid to cause a tank overflow. Let's say just dump drinking water into the tank...
- Sebb767 5y ago
  It seems very likely to me that they carry more than 1L of fluid per passenger, plus there's also the crew. So yes, they could :) Of course, if they dump all their drinking water, it'll be hard to reach the maximum pee capacity per passenger. But you could always resort to dumping food.
  - ethbr0 5y ago
    Each one of us carries about 5L of fluid... it's just kind of mission-critical.
    - Sebb767 5y ago
      Well, if we go down that route, you could just as well dump a few passengers down there. But I guess that wasn't the spirit of the above question :) Allthough the motivation for overfilling a plane waste tank seems dubious overall, so who am I to judge.
  - markus_zhang 5y ago
    I'm thinking about the alcohol and soft drinks on plane. But maybe they don't have much on board.
josefx 5y ago
The total capacity is 1135 litres, how much safety margin does the tank have build in and how would an almost full tank affect flight behavior?
- lmilcin 5y ago
  First of all, all that pee is on the plane when it lifts off, in one form or another. The only thing that changes is distribution of mass (depending on where the tank is and where they keep bottles with drinks). A tonne of pee gathered from all over the plane is most likely less effect than 3-4 people moving from one end to another end of the plane. So a stewardess with help and a cart. Second, pilots can trim the plane while in flight. Third, no safety margin is needed here because this is not a safety problem. The amount of pee that can be deposited into the tanks is limited by the amount of pee they can physically hold at the start of the flight plus the amount of drinks they can consume during flight. But more realistically, on a long flight, it is just the amount of drinks they can consume assuming they drinks are mostly used to replenish whatever they have peed. Most people try to empty their bladder before flight and are willing to have full bladder when they leave the plane (to relieve themselves afterwards) so I think even this is already a little pessimistic. On 747-400 you have max 660 passengers. 1135L divided by 660 passengers gives ~1.7L per passenger on average. Which is a lot. Consider this is an average -- some people may drink way more than that but most people drink less than that in a day. So it seems it might be possible to run out of the tank -- if you have a very long economy flight in a large plane converted to densest possible seating arrangement and if you are willing to believe people will be buying over 1.7L of fluids per person on an economy flight. Of course, all that calculation goes out the window if you plan to fly an economy flight full of Australian Oktoberfest fans directly from Germany to Sydney.
  - sramam 5y ago
    > The only thing that changes is distribution of mass (depending on where the tank is and where they keep bottles with drinks). A tonne of pee gathered from all over the plane is most likely less effect than 3-4 people moving from one end to another end of the plane. So a stewardess with help and a cart. My informal search [1, 2] seems to indicate that every galley seems to have WC close by, though not vice-versa. Would never have thought to attribute that to an engineering decision before this discussion! [1] https://theflight.info/seat-map-boeing-737-800-united-airlines-best-seats-in-plane/ https://theflight.info/seat-map-boeing-737-800-united-airlin... [2] https://theflight.info/seat-map-airbus-a320-200-united-airlines-best-seats-in-plane/ https://theflight.info/seat-map-airbus-a320-200-united-airli... PS: Also amazing that thanks to COVID, I actually had to look up images of airplane layouts!
denni9th 5y ago
Interesting, but what about the excrement and toilet paper that (I assume) ends up in the same tank?
- dahfizz 5y ago
  I imagine they use the same chemicals as marine toilets / portapotties. It breaks down poop and toilet paper into a liquid so that it can be pumped / emptied easily. Not sure why the article focuses solely on urine...
  - mattmaroon 5y ago
    Those chemicals don’t liquefy solid waste instantly. They won’t be very effective in the timespan of a flight. Most likely they use a macerator pump that accomplishes it physically and instantaneously.
fortran77 5y ago
Solution: Pay toilets in the coach cabin.
- geodel 5y ago
  In this case, it could be advantage for piss-poor people like me.
- pavel_lishin 5y ago
  Problem: cleaning up water bottles full of pee after deboarding. Worse problem: cleaning up un-capped, tipped-over bottles that are no longer full of pee after deboarding.
  - sysadmindotfail 5y ago
    "Come on, give me that booze, you little pumpkin pie, hair-cutted freak, come on!" "Tic-tac, sir?"
- mschuster91 5y ago
  That has the downside that a penny-pinching passenger might attempt to "hold it in" and then, shocked by a turbulence, involuntarily ejecting what was "held back"... leading to the plane needing an extra cleaning or being taken out of service. There's a reason why even Ryanair, otherwise the leader in borderline unethical airline behavior, quietly buried their 2010 attempt to introduce a loo charge [1]. [1]: https://www.theguardian.com/business/2009/mar/05/ryanair-toilet-charge https://www.theguardian.com/business/2009/mar/05/ryanair-toi...
  - usrusr 5y ago
    Can't beat a reductio ad Ryanair argument!
  - benbristow 5y ago
    Another reason could be due to smokers. There's a reason toilets on airplanes still legally need to have an ashtray - there's still people who are willing to break the rules to have a fix so it's safer to at least provide somewhere safe to put a cigarette out. Charging for the toilet could just encourage those same people to light-up in the main cabin.
gootler 5y ago
aaron695 5y ago
iamgopal 5y ago
That is just 2B. A simple STP plant can handle this. Not every billion is a big number. Edit : Writer of the article also thinks that.
- mattmaroon 5y ago
  That’s true, my small city processes the waste from over a million people (they provide sewer to the suburbs) every day which is about the same as the number of Americans who fly. Plus they process all the other water that goes down the sewer from showering, laundry, etc. So just one small city is probably processing much more than all the planes in the country combined.
  - bcrosby95 5y ago
    And people actively avoid using airplane toilets, so airplane usage would be even lower.
- toss1 5y ago
  Yup. liters makes it sound like a big number, but using the author's example: >> The world’s busiest airport by passenger volume, Guangzhou, could have handled 5.14 million litres of pee in April 2021. That converts to about 43k 55-gallon barrels per year, or about 118 barrels per day. An insustry standard oil tanker truck is about 210 barrels, range 50-300 [0]. So, all in all, pretty manageable. [0] https://www.reference.com/business-finance/capacity-tanker-truck-e378ab43259d6ab https://www.reference.com/business-finance/capacity-tanker-t...
ravenstine 5y ago
I haven't had to take a dump on an airplane in years. My rule is to eat and drink as little as possible before a flight, ideally not eating at all. If I do eat, hopefully it's high protein and low in fiber. As a result I usually don't need to use the lavatory, which is nice because it has made me much less apprehensive about getting a window seat. I wish more people had this mindset. On so many flights I've had, seemingly half the plane is ready to take a shit. My only explanation is that they're overnourished on the Standard American Diet. Imagine how much less waste would have to be pumped out of airplanes.
- the_only_law 5y ago
  Never took a dump on a plane, but I hate airports, and usually find myself at the bar before boarding which more than often has led to a painful urge to pee at the worst times.
- tomcam 5y ago
  OK that first sentence was the line I have least expected to start a Hacker News comment ever. Also you are correct on all counts. I developed these same techniques to avoid peeing during the opera but they ported well to air travel.
- astrea 5y ago
  One could also consider that not everyone is in the healthiest state due to illness or chronic disease and not just immediately assume moral failing.
- noodlesUK 5y ago
  I get this for short haul flights, but I can’t imagine not having to pee over the course of a >12h flight…
  - GekkePrutser 5y ago
    That would not be healthy indeed. Dehydration combined with sitting still for so long is a recipe for thrombosis.
- 5y ago
S_A_P 5y ago
I like articles like this that encourage you to think about details that are often missed when it comes to making everyday life run smoothly. I also get that it makes sense to time box it to a year to give a sense of scale to the problem. However the headline is written in a click bait-ey way that rubs me the wrong way. I know you gotta do it for the clicks and all, but I think we need to find a better way to capture the attention of readers.
- Brave-Steak 5y ago
sometemp 5y ago
https://inhabitat.com/the-incredible-story-of-how-the-burj-khalifas-poop-is-trucked-out-of-town/ https://inhabitat.com/the-incredible-story-of-how-the-burj-k... 15 tons equates to over 10k liters, if you are interested https://www.thecalculatorsite.com/conversions/common/liters-to-metric-tons.php https://www.thecalculatorsite.com/conversions/common/liters-...
dehrmann 5y ago
The onboard tank capacity is probably one of those things that needs to be overprovisioned so it practically never gets full. You want to run out of fuel and have to divert more often than run out of space in that tank.
supernova87a 5y ago
I would suggest that this is actually more efficient. When people use the toilet on planes, the design of the toilets uses so much less water than a toilet on the ground, in the airport, and how much a flush of water takes. So if you assume that people were going to use the bathroom regardless, they just saved the processing of a lot of water by doing it on the plane. Probably ounces versus gallons. (~100 mL vs. 1-2 L) (parenthetical note, sometimes I wonder if a vacuum toilet would become available for home use, it's so effective!) Now certainly, flying around to use the bathroom used up a lot more energy, but regardless... Also, you might ask whether people tend to drink more than average because they're offered drinks on a plane. I used to wonder, considering the hundreds of pounds of water/soda/etc loaded on a plane, as people drink and consume it all, wouldn't it be efficient for the plane to dump that water in flight and save the weight and extend the range. Turns out (of course) that is so negligible compared to the overall weight of the plane...
- brnt 5y ago
  > parenthetical note, sometimes I wonder if a vacuum toilet would become available for home use, it's so effective I've heard it said that plumbing issues dramatically increase with modern, water-efficient toilets. It's not hard to imagine why. Sewer usage and maintenance are at a far lower rate, so stool will settle and clog when ever smaller amounts of water are introduced. I'm not sure this problem can be solved, assuming regular sewage as the method of disposal.
  - l1tany11 5y ago
    A lot of problems are also due to old systems. Ask any plumber. The plastic pipes are smooth inside. Old pipes weren’t only rough, they degrade. Cast iron sloughs off into itself. There was a kind of pipe that was used that was basically tar paper; it broke down and clogged itself (like cast iron). A new building with new toilets should work very well. Replacing your toilet may not help if your pipes from the 60s are basically nonexistent.
    - mveety 5y ago
paxys 5y ago
That's like saying airports have to deal with x number of planes taking off and landing. No shit (heh), that's the point of being an airport.
asah 5y ago
Curious if they're monitoring these for COVID...
MarkusWandel 5y ago
Two billion litres a year. Impressive number at first glance. But let's say my own household of 4 was able to keep water consumption down to 500L/day (I wish), that's already around 180K litres/year just for my house. So divided into 2B, that's about 11K houses' worth of wastewater. A modest size town's worth, for all the air travel worldwide.

I wonder if it has enough liquid to cause a tank overflow. Let's say just dump drinking water into the tank...

Sebb767 5y ago
It seems very likely to me that they carry more than 1L of fluid per passenger, plus there's also the crew. So yes, they could :) Of course, if they dump all their drinking water, it'll be hard to reach the maximum pee capacity per passenger. But you could always resort to dumping food.
- ethbr0 5y ago
  Each one of us carries about 5L of fluid... it's just kind of mission-critical.
  - Sebb767 5y ago
    Well, if we go down that route, you could just as well dump a few passengers down there. But I guess that wasn't the spirit of the above question :) Allthough the motivation for overfilling a plane waste tank seems dubious overall, so who am I to judge.
- markus_zhang 5y ago
  I'm thinking about the alcohol and soft drinks on plane. But maybe they don't have much on board.

The total capacity is 1135 litres, how much safety margin does the tank have build in and how would an almost full tank affect flight behavior?

lmilcin 5y ago
First of all, all that pee is on the plane when it lifts off, in one form or another. The only thing that changes is distribution of mass (depending on where the tank is and where they keep bottles with drinks). A tonne of pee gathered from all over the plane is most likely less effect than 3-4 people moving from one end to another end of the plane. So a stewardess with help and a cart. Second, pilots can trim the plane while in flight. Third, no safety margin is needed here because this is not a safety problem. The amount of pee that can be deposited into the tanks is limited by the amount of pee they can physically hold at the start of the flight plus the amount of drinks they can consume during flight. But more realistically, on a long flight, it is just the amount of drinks they can consume assuming they drinks are mostly used to replenish whatever they have peed. Most people try to empty their bladder before flight and are willing to have full bladder when they leave the plane (to relieve themselves afterwards) so I think even this is already a little pessimistic. On 747-400 you have max 660 passengers. 1135L divided by 660 passengers gives ~1.7L per passenger on average. Which is a lot. Consider this is an average -- some people may drink way more than that but most people drink less than that in a day. So it seems it might be possible to run out of the tank -- if you have a very long economy flight in a large plane converted to densest possible seating arrangement and if you are willing to believe people will be buying over 1.7L of fluids per person on an economy flight. Of course, all that calculation goes out the window if you plan to fly an economy flight full of Australian Oktoberfest fans directly from Germany to Sydney.
- sramam 5y ago
  > The only thing that changes is distribution of mass (depending on where the tank is and where they keep bottles with drinks). A tonne of pee gathered from all over the plane is most likely less effect than 3-4 people moving from one end to another end of the plane. So a stewardess with help and a cart. My informal search [1, 2] seems to indicate that every galley seems to have WC close by, though not vice-versa. Would never have thought to attribute that to an engineering decision before this discussion! [1] https://theflight.info/seat-map-boeing-737-800-united-airlines-best-seats-in-plane/ https://theflight.info/seat-map-boeing-737-800-united-airlin... [2] https://theflight.info/seat-map-airbus-a320-200-united-airlines-best-seats-in-plane/ https://theflight.info/seat-map-airbus-a320-200-united-airli... PS: Also amazing that thanks to COVID, I actually had to look up images of airplane layouts!

denni9th 5y ago

Interesting, but what about the excrement and toilet paper that (I assume) ends up in the same tank?

dahfizz 5y ago
I imagine they use the same chemicals as marine toilets / portapotties. It breaks down poop and toilet paper into a liquid so that it can be pumped / emptied easily. Not sure why the article focuses solely on urine...
- mattmaroon 5y ago
  Those chemicals don’t liquefy solid waste instantly. They won’t be very effective in the timespan of a flight. Most likely they use a macerator pump that accomplishes it physically and instantaneously.

fortran77 5y ago

Solution: Pay toilets in the coach cabin.

geodel 5y ago
In this case, it could be advantage for piss-poor people like me.
pavel_lishin 5y ago
Problem: cleaning up water bottles full of pee after deboarding. Worse problem: cleaning up un-capped, tipped-over bottles that are no longer full of pee after deboarding.
- sysadmindotfail 5y ago
  "Come on, give me that booze, you little pumpkin pie, hair-cutted freak, come on!" "Tic-tac, sir?"
mschuster91 5y ago
That has the downside that a penny-pinching passenger might attempt to "hold it in" and then, shocked by a turbulence, involuntarily ejecting what was "held back"... leading to the plane needing an extra cleaning or being taken out of service. There's a reason why even Ryanair, otherwise the leader in borderline unethical airline behavior, quietly buried their 2010 attempt to introduce a loo charge [1]. [1]: https://www.theguardian.com/business/2009/mar/05/ryanair-toilet-charge https://www.theguardian.com/business/2009/mar/05/ryanair-toi...
- usrusr 5y ago
  Can't beat a reductio ad Ryanair argument!
- benbristow 5y ago
  Another reason could be due to smokers. There's a reason toilets on airplanes still legally need to have an ashtray - there's still people who are willing to break the rules to have a fix so it's safer to at least provide somewhere safe to put a cigarette out. Charging for the toilet could just encourage those same people to light-up in the main cabin.

gootler 5y ago

aaron695 5y ago

iamgopal 5y ago

That is just 2B. A simple STP plant can handle this. Not every billion is a big number. Edit : Writer of the article also thinks that.

mattmaroon 5y ago
That’s true, my small city processes the waste from over a million people (they provide sewer to the suburbs) every day which is about the same as the number of Americans who fly. Plus they process all the other water that goes down the sewer from showering, laundry, etc. So just one small city is probably processing much more than all the planes in the country combined.
- bcrosby95 5y ago
  And people actively avoid using airplane toilets, so airplane usage would be even lower.
toss1 5y ago
Yup. liters makes it sound like a big number, but using the author's example: >> The world’s busiest airport by passenger volume, Guangzhou, could have handled 5.14 million litres of pee in April 2021. That converts to about 43k 55-gallon barrels per year, or about 118 barrels per day. An insustry standard oil tanker truck is about 210 barrels, range 50-300 [0]. So, all in all, pretty manageable. [0] https://www.reference.com/business-finance/capacity-tanker-truck-e378ab43259d6ab https://www.reference.com/business-finance/capacity-tanker-t...

ravenstine 5y ago

I haven't had to take a dump on an airplane in years. My rule is to eat and drink as little as possible before a flight, ideally not eating at all. If I do eat, hopefully it's high protein and low in fiber. As a result I usually don't need to use the lavatory, which is nice because it has made me much less apprehensive about getting a window seat. I wish more people had this mindset. On so many flights I've had, seemingly half the plane is ready to take a shit. My only explanation is that they're overnourished on the Standard American Diet. Imagine how much less waste would have to be pumped out of airplanes.

the_only_law 5y ago
Never took a dump on a plane, but I hate airports, and usually find myself at the bar before boarding which more than often has led to a painful urge to pee at the worst times.
tomcam 5y ago
OK that first sentence was the line I have least expected to start a Hacker News comment ever. Also you are correct on all counts. I developed these same techniques to avoid peeing during the opera but they ported well to air travel.
astrea 5y ago
One could also consider that not everyone is in the healthiest state due to illness or chronic disease and not just immediately assume moral failing.
noodlesUK 5y ago
I get this for short haul flights, but I can’t imagine not having to pee over the course of a >12h flight…
- GekkePrutser 5y ago
  That would not be healthy indeed. Dehydration combined with sitting still for so long is a recipe for thrombosis.
5y ago

S_A_P 5y ago

I like articles like this that encourage you to think about details that are often missed when it comes to making everyday life run smoothly. I also get that it makes sense to time box it to a year to give a sense of scale to the problem. However the headline is written in a click bait-ey way that rubs me the wrong way. I know you gotta do it for the clicks and all, but I think we need to find a better way to capture the attention of readers.

Brave-Steak 5y ago

sometemp 5y ago

https://inhabitat.com/the-incredible-story-of-how-the-burj-khalifas-poop-is-trucked-out-of-town/ https://inhabitat.com/the-incredible-story-of-how-the-burj-k... 15 tons equates to over 10k liters, if you are interested https://www.thecalculatorsite.com/conversions/common/liters-to-metric-tons.php https://www.thecalculatorsite.com/conversions/common/liters-...

dehrmann 5y ago

The onboard tank capacity is probably one of those things that needs to be overprovisioned so it practically never gets full. You want to run out of fuel and have to divert more often than run out of space in that tank.

supernova87a 5y ago

I would suggest that this is actually more efficient. When people use the toilet on planes, the design of the toilets uses so much less water than a toilet on the ground, in the airport, and how much a flush of water takes. So if you assume that people were going to use the bathroom regardless, they just saved the processing of a lot of water by doing it on the plane. Probably ounces versus gallons. (~100 mL vs. 1-2 L) (parenthetical note, sometimes I wonder if a vacuum toilet would become available for home use, it's so effective!) Now certainly, flying around to use the bathroom used up a lot more energy, but regardless... Also, you might ask whether people tend to drink more than average because they're offered drinks on a plane. I used to wonder, considering the hundreds of pounds of water/soda/etc loaded on a plane, as people drink and consume it all, wouldn't it be efficient for the plane to dump that water in flight and save the weight and extend the range. Turns out (of course) that is so negligible compared to the overall weight of the plane...

brnt 5y ago
> parenthetical note, sometimes I wonder if a vacuum toilet would become available for home use, it's so effective I've heard it said that plumbing issues dramatically increase with modern, water-efficient toilets. It's not hard to imagine why. Sewer usage and maintenance are at a far lower rate, so stool will settle and clog when ever smaller amounts of water are introduced. I'm not sure this problem can be solved, assuming regular sewage as the method of disposal.
- l1tany11 5y ago
  A lot of problems are also due to old systems. Ask any plumber. The plastic pipes are smooth inside. Old pipes weren’t only rough, they degrade. Cast iron sloughs off into itself. There was a kind of pipe that was used that was basically tar paper; it broke down and clogged itself (like cast iron). A new building with new toilets should work very well. Replacing your toilet may not help if your pipes from the 60s are basically nonexistent.
  - mveety 5y ago

paxys 5y ago

That's like saying airports have to deal with x number of planes taking off and landing. No shit (heh), that's the point of being an airport.

asah 5y ago

Curious if they're monitoring these for COVID...

MarkusWandel 5y ago

Two billion litres a year. Impressive number at first glance. But let's say my own household of 4 was able to keep water consumption down to 500L/day (I wish), that's already around 180K litres/year just for my house. So divided into 2B, that's about 11K houses' worth of wastewater. A modest size town's worth, for all the air travel worldwide.