I just got back from Burning Man, a one-week desert festival of arts and music (and sex and drugs). In the beginning, Burning Man was about blowing things up. As the police do not take kindly to that behavior, BM moved into the desert -- the Black Rock Desert, which is about 100 miles north of Reno, NV. In the desert, blowing things up is easy, but living is hard. Without food, water or shelter, everyone had to be "radically self-reliant", i.e., bring those items.
Since this beginning (early 1990s), a few things have changed: many more people are there (48,000 this year); cleaning up the mess has become more important ("respect the Playa"); and surviving has gotten easier (in two ways: some people have more money, so can bring larger vehicles that others can use, and BM sells ice on the Playa.)
The use and disposal of water at BM is interesting -- first because everyone brings many bottles of it and second because they are supposed to evaporate or carry out the gray water from showers, etc -- not drop it on the Playa, which is an evaporated lake but apparently "vulnerable" to water (or perhaps dirty water).
The irony is that shlepping in water and taking out all those containers are not exactly ecological activities. (The theme this year was "Green Man", so this is relevant.) Further, gray water handling is terrible (evaporation doesn't work very well), inconvenient and makes people guilty when they fail to "do the right thing".
This topic hits right on the ecological/sustainable element of BM. Although people are supposed to be sustainable and zero-emission on the Playa, the considerable energy they put into preparation, supplies, etc. far outweighs the energy they use on the playa. If BM were analyzed on an annual (not one-week) basis, it's ecological footprint would be huge. (One of the bigger exhibits (the Oil Derrick) used 20,000 gallons of gas, for example)
Bottom Line: A city of nearly 50,000 people in the desert is not the best place to look for sustainability. Burners know that and don't care: they want to party. The real sustainable action would be to shut BM down and plant trees, but that sustainable life is hardly worth living, is it?