The 17 century barn I have been working on uses a long drop, simply because it does not get enough deposits to make a composting one worthwhile, she reckons that they get less than a bucket a week, we generate that once a month. For urinals they have 2, one a standing and one squatting, and you go on to the grass and weeds that have been put in there for composting as the nitrogen in the pee helps in the process, every now and then they are emptied out onto the main compost heap.
Once the long drop is full it is caped and marked, a new hole dug and the toilet put ovef the top.
