When I tell people that I live in a tiny house most of them want to know about my cooking facilities. When I tell them about my microwave, cook top, and fridge, they realize it's not much different than their kitchen.
But the folks who think to ask about my toilet facilities usually keep their eyebrows up a bit longer. Many people who live in a tiny house use a composting toilet - either a commercial one or a bucket with sawdust. Some people line a 5 gallon bucket with a plastic bag and tie it up and put it in the garbage can each week. (If you think about it, there's a lot of human poop going into the landfills from baby diapers and elder's diapers!) Others decide to actually compost. The Humanure Handbook provides detailed directions about how to safely fertilize poop. However, my host and I decided that it would be best for me to use the toilet inside her house or at school for poo. Setting up a humanure composting system might be the last straw for the neighbors. They've been just fine with a chicken coop and a tiny house, but we don't want to push it.
On the other hand, pee is sterile and it makes a great fertilizer. The garden has lots of non-edible plants so I keep a plastic pitcher inside the bathroom to collect pee. Once or twice a day I dilute the contents of my pee pitcher with water (urine needs to be diluted about 8 parts to 1 with water so it doesn't burn the plants) and dump it on the bushes outside my house. (I've found that daily emptying is necessary so keeping the container small ensures that I'm really good about emptying it frequently!) My guy friends seem to prefer just stepping outside to "water a bush," but the gals who have used my pee pitcher system said it was no big deal. The bamboo loves the nitrogen and I love the simplicity of the system.
There's a whole book about fertilizing with pee called Liquid Gold. There are also periodic articles and essays about using urine as a fertilizer in the news and on blogs. I like this one called "Are We Wasting Human Waste?" I was fascinated when I learned in a permaculture class that humans produce approximately the same amount of nitrogen in their urine each year as it takes to fertilize the food they eat in a year. There is a connection here, but it's been broken. Instead we buy commercial fertilizers, many of them using petroleum products, to fertilize our food crops and we flush our pee into a wastewater treatment system which uses tons of energy and water to process the "waste." Some people are trying to reconnect they nitrogen cycle by fertilizing edible plants with urine. I have a guy friend who found that his tomato plants grew like crazy once he started peeing on them. If you stop to consider it, it's odd that we think nothing of putting other species' poop on our food plants but we're squeamish about using our own sterile urine as a fertilizer. For now I'll stick to fertilizing the bamboo, but I'll keep watching for more research, too.