*shudder*
In North Korea, there were quotas for city dwellers to deliver their euphemisms to the appropriate bureaucracy for use as fertilizer. Dreadful if one were “irregular,” I’m sure.
For a more pleasant aspect, composting toilets, otherwise known as waterless toilets, are available which work to diminish consumption of water as well as to provide a source of nutrient rich material for growing plants.
As supposed space-travelers, intent on the necessity as well as efficiency of recycling programs and procedures, we would do well to be conversant with such equipment.