I don't think plastic alone would heat up (unless you have some very weird plastics). Organics probably would. But for common household garbage, there's not muc

I don't think plastic alone would heat up (unless you have some very weird plastics). Organics probably would. But for common household garbage, there's not much harm in just burying it somewhere, provided it's not leaking or otherwise getting out - plant some trees on top of it and you have a nice park. Toxic garbage is more challenging but regular plastic doesn't seem to be this huge problem if you don't dump it into the river or such.