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> A returnable milk bottle takes much more energy to produce and much more fuel to transport than a plastic carton, and has to make around ten or more trips to

> A returnable milk bottle takes much more energy to produce and much more fuel to transport than a plastic carton, and has to make around ten or more trips to use less energy than a bottle made from polyethylene plastic. This seems like the weakest of presented arguments. Just 10 trips and it's more environmentally friendly? Yeah, seems like reusable milk bottles wins over plastic. That's what, ~10 weeks for payback?

marcosdumay 1mo ago
Returned bottles have a finite lifetime after what they have to be trashed. Glass bottles tend to be reused some (small) tens of times, plastic bottles certainly last a lot less.
- cogman10 1mo ago
  Google AI is saying 25->30 on average with a high of 50. That still ends up being translated to 1/2 to 1/3 (up to 1/5th) the energy of plastic. Glass is also one of the few good cases for recycling.
  - marcosdumay 1mo ago
    Granted, glass bottles are also the one good case for recycling glass. But keep in mind the article's energy number is for plastic bottles, glass uses more energy. Returnable glass bottles are probably better than disposed plastic ones. Returnable plastic bottles (for food) probably aren't.
    - cogman10 1mo ago
      I dug into the linked article because I think the short blurb was a bit vague. This was it's conclusion. (R-PET -> Recycled polyethylene) > Results show that R-PET bottle has the lowest impact for all the selected LCA categories, followed by PET bottle, returnable glass bottle with 8 use cycles, and finally non-returnable bottle. This is due to the savings of virgin materials, its low weight and its lower energy consumption in the production phase and transports. The most impactful solution is the non-returnable glass bottle, while better results are obtained using returnable glass bottles: using many times the same bottle, there is only a production and disposal phase, then the majority of the impacts are connected to the cap, label and washing and transport phase. However, even considering 30 use cycles before the glass bottle disposal, its impact is not comparable to the R-PET bottle. Perhaps, reducing the glass bottle weight as much as possible and modifying the cap, its environmental impact could be reduced, but there are still some researches to do for ensuring a bottle shock resistance. According to the MLI proposed, non-returnable glass bottles are the worst material option, followed by PET, R-PET and finally returnable glass bottles. As far as this indicator is concerned, investing on glass bottles reuse and augmenting the incentives of the bottle restitution will help to reduce the marine litter. Furthermore, from a methodological point of view, possible changes could be made to this indicator, such as the adding of other factors or the use of specific weight for each parameter, as already expected but not applied in this study. [1] The study argues that glass bottles shouldn't be used beyond 8 times mainly because of the other environmental factors around washing and relabeling. I'm not actually sure where the OP got 10 from. I guess the only additional defense I'd offer over reusing glass is the chemicals used in washing get removed in water treatment and glass doesn't ultimately turn into microplastics (Although... the lid does which is unfortunate and could potentially be fixed [2]). [1] https://link.springer.com/article/10.1007/s11367-020-01804-x https://link.springer.com/article/10.1007/s11367-020-01804-x [2] https://www.anses.fr/en/content/caps-glass-bottles-contaminate-beverages-microplastics https://www.anses.fr/en/content/caps-glass-bottles-contamina...

marcosdumay 1mo ago

Returned bottles have a finite lifetime after what they have to be trashed. Glass bottles tend to be reused some (small) tens of times, plastic bottles certainly last a lot less.

cogman10 1mo ago
Google AI is saying 25->30 on average with a high of 50. That still ends up being translated to 1/2 to 1/3 (up to 1/5th) the energy of plastic. Glass is also one of the few good cases for recycling.
- marcosdumay 1mo ago
  Granted, glass bottles are also the one good case for recycling glass. But keep in mind the article's energy number is for plastic bottles, glass uses more energy. Returnable glass bottles are probably better than disposed plastic ones. Returnable plastic bottles (for food) probably aren't.
  - cogman10 1mo ago
    I dug into the linked article because I think the short blurb was a bit vague. This was it's conclusion. (R-PET -> Recycled polyethylene) > Results show that R-PET bottle has the lowest impact for all the selected LCA categories, followed by PET bottle, returnable glass bottle with 8 use cycles, and finally non-returnable bottle. This is due to the savings of virgin materials, its low weight and its lower energy consumption in the production phase and transports. The most impactful solution is the non-returnable glass bottle, while better results are obtained using returnable glass bottles: using many times the same bottle, there is only a production and disposal phase, then the majority of the impacts are connected to the cap, label and washing and transport phase. However, even considering 30 use cycles before the glass bottle disposal, its impact is not comparable to the R-PET bottle. Perhaps, reducing the glass bottle weight as much as possible and modifying the cap, its environmental impact could be reduced, but there are still some researches to do for ensuring a bottle shock resistance. According to the MLI proposed, non-returnable glass bottles are the worst material option, followed by PET, R-PET and finally returnable glass bottles. As far as this indicator is concerned, investing on glass bottles reuse and augmenting the incentives of the bottle restitution will help to reduce the marine litter. Furthermore, from a methodological point of view, possible changes could be made to this indicator, such as the adding of other factors or the use of specific weight for each parameter, as already expected but not applied in this study. [1] The study argues that glass bottles shouldn't be used beyond 8 times mainly because of the other environmental factors around washing and relabeling. I'm not actually sure where the OP got 10 from. I guess the only additional defense I'd offer over reusing glass is the chemicals used in washing get removed in water treatment and glass doesn't ultimately turn into microplastics (Although... the lid does which is unfortunate and could potentially be fixed [2]). [1] https://link.springer.com/article/10.1007/s11367-020-01804-x https://link.springer.com/article/10.1007/s11367-020-01804-x [2] https://www.anses.fr/en/content/caps-glass-bottles-contaminate-beverages-microplastics https://www.anses.fr/en/content/caps-glass-bottles-contamina...