I followed this thread many years ago and came up with my own evaporator design based on information I gleaned here. I built my design and have taken it to the playa 2 years in a row and it seems to perform pretty well.
Here's what I built:
This picture was taken on year 1, in the middle of a raging dust storm. Note: not much water dripping around!
Bascially, the idea is this:
5 Gallon buckets hold your greywater. The large green flower pots are where you dump your greywater into the system. The big black filterfabric "coffee filters" strains out the solids (and most of the playa mud). The solar powered fountain pump pumps the grey water up to the top of the towels (it can only lift about 4' or so), then it dribbles it out, keeping the towels constantly wet. There are some plastic coat hangers behind the towels that keeps them spread apart at the top, allows for good airflow too.
I found this contraption would evaporate about 5 gallons per day, depending on conditions.
You don't need FLOWING water for evaporation, just WET SURFACE AREA! As long as the towels are wet, water is evaporating. On some days, light overcast, light breeze, the pump was barely pumping, but none of the water was going back into the buckets, it was evaporating before it got to the bottom of the towels.
1) The system is easily expandable: you can start with just one bucket, and add more as you need it (by turning valves on the connector hoses at the bottom of the buckets). I usually have 3 buckets connected together, but you could easily add more, and even add more pumps and towels too.
2) Very little dispersion, even in high winds.
3) The greywater is pretty much contained in closed spaces, and constantly goes through the filter fabric to keep solids out.
4) Easy to add greywater: just dump it in one of the flowerpots and it filters it and adds it to the system, gravity fed.
5) When you're ready to go home, you can sprinkle the filtered greywater on the street (the bucket with the valves on it in the picture makes this very easy), or you can put a lid on the bucket and truck it out. Also, just toss the towels in another bucket, wrap up the filter fabric and chuck it in a trash bag, and throw all the hoses and pumps in with the towels. Keeps the "yick" factor somewhat better contained on your way home. Then wash everything really good when you get home.
6) Packed up, it doesn't take much space. The buckets nest, and the open bucket has enough room for the hoses, pump, panel, towels, rope and clothes pins. The frame comes apart too.
1) Its not the quickest evaporator out there!
2) Performance relies heavily on the solar powered pump.
3) Cleaning up any greywater evap system sucks.
This year we're thinking of splurging on an RV, and if we do, I'm directly connecting our RV's greywater tank to this system. I might not even need to touch greywater at all! YAY!