At my usual pub the firkins are rolled off onto a pad the rolled and dropped about 3m to the cellar. There was a kilderkin - a proper coopered one - and I don't know how that was lowered - hoist at a guess. Dropping it could be messy. The reason for all that ale being poured away during the first lockdown was because the drays weren't equipped for lifting full containers. The disposal was at a rate set by the Environment Agency so that the treatment plants didn't get pissed.