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200 plus gallons

2014-06-25 15:31:28.438627+00 by meuon 15 comments

As there are some very inventive people that also go to Burning Man that hang here, I thought I'd put some musing here. Nancy and I are going to be a part of Spiritual Playa this year, and my project is to deal with waste water (grey water), that, because of the nature of the camp, could be 200-300 gallons of grey (post bathing) water. We would like to evaporate as much as we can, but could haul out a few hundred gallons in the drums we haul water in, if we clean/sterilize them for re-use next year. In doing some research, and getting ready I find the following swags:

  • Surface area is the biggest factor.
  • I might be able to add energy to the water
  • Evap Calc says 10 sq meters of surface can evaporate 4+ kg of water per hour
  • I have about 1kWh per day to run pumps and motors.
  • 100 Gallons of water weighs about 835 pounds or 378 kilograms
  • Guess: 5-6 days of needing to evaporate water = 144 hours, 70 of bright daylight
  • 378 / 4kg/hr = 94 hours at 10sqmeters for 100 gallons
Which means I need more area, (rotating wheels, etc..) or adding heat... am considering parabolic mirrors, solar steam generator..

Laugh at me.. please.

[ related topics: Religion Burning Man Interactive Drama Music Nature and environment Photovoltaics ]

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comments in ascending chronological order (reverse):

#Comment Re: made: 2014-06-25 16:08:03.226749+00 by: Dan Lyke

Many years ago, I tried a large tarp spread out with 2x4 or similar (I forget just what I did) around the edges to form a lip. I remember it being a particularly cool year, but I remember that with that passive mechanism of probably somewhere north of 100 square feet but probably less than 400, we simply could not evaporate the water fast enough.

I'm wondering if some sort of fountain/waterfall thing might help more. Could be a decorative element...

#Comment Re: made: 2014-06-25 17:23:07.483226+00 by: meuon

Evap ponds barely work. I've used them before also. I'm currently planning on having an 8' tall x 32' (around) vertical cloth surface I'll be pumping water up to and soaking (float switch controlled). I looked at ultrasonics and other methods to increase evaporation, the winning idea might be to use a "solar boiler" ie: a parabolic reflector with some copper pipes in the center, to heat the water up, maybe even to steam levels. (I'd love to make a steam whistle!).

In reality, I'm thinking a water collection, filtration and collection and more filtration might allow me to clean up the water enough to pump and transport it out will take care of most of it. I wish I hadn't recently tossed an old waterbed mattress... Some of it, after having been filtered, flocculated and chlorinated a little can be use for "dust control".

Gabriel says that they expect to use less than a cup of water per person for foot washing, add general camp use (bathing... etc..) but I'd like to expect and be ready for 200 gallons of grey water.

And yes, It's Burning Man: Where engineering meets art. It should be something interesting if not actually attractive.

#Comment Re: made: 2014-06-25 17:26:35.926513+00 by: spc476

Why not a still? Or are the fuel requirements too excessive for that approach?

#Comment Re: made: 2014-06-25 17:42:39.798391+00 by: meuon [edit history]

"A Still".. is essentially what I have in mind for "solar boiler". I've seen some designs that look like they would work well pretty cheaply. Some copper tubes into the middle of a parabolic trough reflector like:


Letting it boil out one end, with the run-over going back into the pond to heat it up.

#Comment Re: made: 2014-06-25 18:09:36.291286+00 by: Larry Burton [edit history]

I'm thinking of a shallow pool and a slow turning drum covered with burlap.

Of course with this being grey water that will be one more nasty drum when you tear it down.

#Comment Re: made: 2014-06-26 00:08:19.03442+00 by: meuon

The moving drum design is common at Burning Man, and works reasonably well for normal camp grey water use.. say 50 gallons total. The drum cloth typically gets dried and burned. Typical small-ish "Evapatron" handles about 5 gallons per day. I need maybe: 50 per day on peak days?

#Comment Re: made: 2014-06-26 00:10:30.457417+00 by: brennen

I was thinking of something similar to the drum with burlap - maybe a big sheet of the stuff rotating like those old-school cloth towels you used to see in seedy gas-station restrooms?

#Comment Re: made: 2014-06-26 05:27:20.667289+00 by: nkane

Maybe it goes against the spirit of the event but after going as long as I have it has become worth it to throw some cash at the poo pumper trucks and just have them pump the evap pan. Soooooo much easier.

Last time we had some sort of evap gray water pump trickling through cloth sort of thing we caught a newb rinsing his toothbrush in it. Blech!

#Comment Re: made: 2014-06-26 11:32:00.081184+00 by: meuon

nkane, that makes Backup Plan C. I'll add it to the list :) Plan B is to haul it back out in the barrels we brought it in.

"Spirit" and "reality" are sometimes very different things. It's fun to try, and to me it's an interesting engineering project with a modest budget. ie: entertaining.

#Comment Re: made: 2014-06-27 12:41:11.178994+00 by: TheSHAD0W

I'm not sure why you're going to all that trouble to discard or recycle water when the desert plants can use every bit of extra moisture you're willing to donate. Filter and spray it out into the desert.

#Comment Re: made: 2014-06-27 13:54:22.840241+00 by: Dan Lyke

There are no plants, but that particular location is pretty wet about 3' down (it's an old lake bed, there can be surface water during the winter, and I believe there are brine shrimp).

Meuon can toss in his own reasons, but I believe there are two reasons to not dump the water:

#Comment Re: made: 2014-06-27 14:26:43.23825+00 by: meuon

There might be a small amount of fats.. but there will be some "natural" detergents, and other biological stuff that we want to minimize. A few pool chlorine tabs will take care of that. Dan pegged it well with #2. I'm a "caver" and a "camper". We are at a campground (Fall Creek Falls, TN) right now, and our campground practices are radically different from many of the people around us. I'm not a nutcase, and my views are certainly not what they were 20+ years ago, because I've been exposed to people that put thought into what their impact on the area around them is. Dan was/is one of many of those people.

TheSHADOW, if we haul out water (likely) and I'm satisfied with the cleanliness/usefulness of it, we might spread it where it could be beneficial, but once on the road, might as well feed it back into the Reno wastewater treatment system.

#Comment Re: made: 2014-06-27 18:12:11.494611+00 by: Dan Lyke

Yeah, back when I was going there was big lip service to "leave no trace", with varying levels of adherence. The first year I went to help with clean-up we were going through burn piles with magnets to get the metal out and trying to dig out most of the charcoal and unburned organic matter, the last year all the burns were supposed to be done on protective surfaces so the ashes got removed, but there was glitter, trinkets and trash scattered around camp sites, and one guy in a school bus who had to be forcibly evicted a week after the event left a labyrinth of small stones that wouldn't have raised an eyebrow in the oft-traveled hills above Marin, but stood out like a sore thumb on the vast flat expanse of the playa.

And cavers have a level of "leave no trace" that can be down to the level of "oil from your fingertips" obsessive, for good reason (cave ecologies are very fragile).

So, yeah: The consciousness raising about what really constitutes "leave no trace" vs "well, it'll look about the same when we're camped here next year" is pretty huge.

#Comment Re: made: 2014-06-27 23:07:47.174024+00 by: crasch

I'm with nkane. A large trailer mounted tank that get's pumped out during the week is the way to go. No giant, ugly evap. pond polluting the visual environment, no janky evap. machine to maintain, no filthy tarp to deal with at the end, no drums of waste water to take home.

If you decide to store barrels of waste water to bring home, be sure to add pool shock or some other treatment to prevent fermentation. I discovered this the hard way, when several 5 gallon buckets of waste water exploded in my van on the way home.

#Comment Re: made: 2014-06-28 09:22:09.015424+00 by: meuon

The visual and "nostril?" of that is unsettling. Will bring extra pool/spa chlorine tabs.