Processing the sewage produced by a vast horde of humans isn’t a particularly easy task. It requires quite a lot of infrastructure, such as processing plants, transport links to move the sewage to them, pipes that can take excrement from people’s houses to somewhere else for processing, and so forth. In so-called ‘Western’ nations, we use an awful lot of water processing our shit, but not all places have so much water available to use. (Arguably, we don’t either, and we need to start thinking of some better solution.) What seems like the best way forward is to re-use our sewage as fertilizer. But it needs to be made safe first, as each deposit contains all sorts of nasty viruses, bacteria, and parasites which we don’t really want hanging around. India is one place that faces a huge sewage issue. There’s an interesting article about the problems here. Interestingly, one of the problems mentioned is the way that toilet arrangements affect women, particularly female students. The lack of separate facilities at school plays a big role in their high drop-out rate when they reach puberty. The article doesn’t say, but I’m guessing this is to do with things such as embarrassment over menstruation, and perhaps the threat of sexual groping from horny teen boys also using the lav. Clearly, it’s a bad thing for girls to miss out on an education. The lack of proper toilet facilities is rarely cited as a contributing factor.