Question about bin bags

Hi lads. I’m a new student in Galway. Haven’t got any Irish friends yet so I thought I’d seek help on reddit.

I’m sharing the apartment with 4 other Phds and we’re in a bit of pickle. Long story short, the biodegradable bin bags (the ones used for compost bins) are needing to be changed very frequently (couple days) since they’re quite small. I searched Aldi, Lidl, Tesco, Dunnes and all of them have the same 20 - 25L bags.

That’s basically it. Can you point me to where I can find larger bags. Do they even sell those in bigger sizes?

Cheers!