Deuteronomy 23:10-13

10“1If there is among you any man who is unclean because of a nocturnal emission, then he must go outside the camp; he may not 2reenter the camp. 11But when evening approaches, he shall bathe himself with water, and at sundown he may 3reenter the camp.

12“You shall also have a place allocated outside the camp, so that you may go out there to relieve yourself, 13and you shall have a 4spade among your tools, and it shall be when you sit down outside, you shall dig with it and shall turn and cover up your excrement.