We did have use of the wheel back then and used the same type of mules & horses as the other Southern States.
My guess is urine. I know a John Morrison in Selma, Alabama used to go house to house collecting urine to be used in the making of gunpowder.
BTW the most modern and advanced black powder mill in the world was near Augusta, GA. The chemist in chief discovered several ways to purify the ingredients and the South’s powder was of much better quality than the North’s. It also produced far less smoke as most of it burned.
In fact Dupont made sure through political pull that the factory was destroyed after the war because it was making far better powder than they could.