5 ms·
> You can't really wash a 500-mℓ glass bottle with less than about a liter of water, and to sterilize it you need that water to be at least 60°, preferably more
by jusssi 5y ago
> You can't really wash a 500-mℓ glass bottle with less than about a liter of water, and to sterilize it you need that water to be at least 60°, preferably more like 90°. Heating water from 25° to 60° takes 35 calories per gram; at 4.2 J/cal, that's 150 kJ.
A tiny nitpick. I'm quite sure you can use that same liter of hot water to wash multiple bottles. And even then any facility that washes bottles at scale would use the leftover heat from waste water to heat the fresh water.
- kragen 5y agoI think you're right—and, unless you wash the bottle by hand before sending it to the recycling center, that's not a "tiny nitpick," it demolishes my whole thesis. But maybe the "thesis" was already so full of caveats as to be fairly demolished in the first place, unless you reduce it to "it depends".
- jacquesm 5y agoRecycling waste water is a whole science, this goes for car washes, dishwashers (which now use less water than doing the same thing by hand) and industrial washing of all kinds of materials. The times when water was used just once are long gone, and that's before we get into thermal recycling to ensure that the maximum amount of energy is extracted from whatever waste remains.
- kragen 5y agoDo you have a handle on how efficient these systems are and how much energy it really costs to reuse a glass bottle? Or how to find out?