Naked Science Forum

General Science => Question of the Week => Topic started by: nudephil on 25/11/2020 16:03:44

Title: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: nudephil on 25/11/2020 16:03:44
The latest question of the week comes from listener Robert:

Does household composting release fewer greenhouse gases compared to a landfill?

Title: Re: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: RD on 01/12/2020 15:42:35
Transporting the waste to the landfill site in a diesel-powered truck will add more CO2.
Title: Re: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: Bored chemist on 01/12/2020 19:05:18
In a well built landfill site the methane produced by decay can be trapped and used to produce energy.
Even if it's not a lot of energy, it's a vast improvement on venting methane to the atmosphere because methane is a potent greenhouse gas.
Title: Re: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: RD on 02/12/2020 17:09:38
Even when the garbage trucks are powered by landfill methane (https://latimesblogs.latimes.com/greenspace/2011/07/waste-management-trash-trucks.html),
 there is still the carbon-footprint of making the trucks to consider.
Title: Re: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: Bored chemist on 02/12/2020 17:15:07
Even when the garbage trucks are powered by landfill methane (https://latimesblogs.latimes.com/greenspace/2011/07/waste-management-trash-trucks.html),
 there is still the carbon-footprint of making the trucks to consider.
And there is the carbon footprint of not transporting it to somewhere for proper disposal to also consider.
If you just dump it in the back yard (assuming you have one) it's a methane generator.
Title: Re: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: charles1948 on 04/12/2020 18:15:22
The above replies contain the word "trucks".

This word denotes artificial mechanical vehicles. Powered by combustion of unnatural petroleum or diesel fuels.  Such combustion is bound to result in unnatural gas-emission from the metallic exhaust-pipes of the trucks.

But suppose these artificial, metallic "trucks" were replaced by more natural vehicles. Such as wholly wood-based carts, drawn by natural animals. Like horses or oxen.

What is the objection to using them?

Title: Re: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: Bored chemist on 04/12/2020 18:19:18
What is the objection to using them?
https://en.wikipedia.org/wiki/Great_horse_manure_crisis_of_1894
Title: Re: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: charles1948 on 04/12/2020 23:01:58
What is the objection to using them?
https://en.wikipedia.org/wiki/Great_horse_manure_crisis_of_1894

As you rightly point out, horses have a tendency to deposit their droppings in the street. As the Victorians found out.

But would it not be possible to genetically engineer a horse that didn't do that?  Suppose we could create a new breed of horse that only excreted in its stable, not during its outside excursions.

Is there any reason why that couldn't be done.  With some suitable tinkering with the horse's genes.  Do you see any problem?
Title: Re: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: Bored chemist on 05/12/2020 01:28:07
Suppose we could create a new breed of horse that only excreted in its stable, not during its outside excursions.
Why do you think that would help?
In particular, why do you think it would be different from the much simpler option of putting a nappy on the horse -with a side order of "don't you think the Victorians thought of that?".
All you have done is moved the problem to the suburbs where the people live...
Title: Re: QotW - 20.11.25 - Does composting release fewer greenhouse gases than landfill?
Post by: nudephil on 09/12/2020 12:08:47
We answered this question on the Question of the Week podcast:

https://www.thenakedscientists.com/podcasts/question-week/compost-or-landfill-which-emits-more

Thanks for everyone's contributions, and an interesting discussion around transport emissions.