)'( Greywater Evaporation and Management at Burning Man

This is a record of greywater management after Burning Man 2022. This document covers plans, contingencies, actual use and results. Bear in mind that this is in no way a 'professional' way to manage waste water and might make you sick but it worked fine for us and was a bazzilion dollars cheaper than a pump-out.

A few notes for context and tips.

Evaporation rate: 30~60 gallons per day per sprinkler unit (see details below).
Total system cost: ~$200.
Electrical consumption: ~5 Watts pump, ~150 Watts fans, (~1000 Watts leafblower)
Camp size: 23 people.
Maximum containment capacity: ~1100 gallons.
Burning Man 2022 was exceptionally hot and windy aiding evaporation.
Tank fill depth never exceeded 3 inches and was mostly around 1 inch.
Dig out a divot to make a low spot for a pump intake.
Water use increased sharply around the third day, probably due to showers and dishwashing.
'Running' water was a trigger activated shower, a bug sprayer, and foot pump sink (made with a boat fuel squeeze bulb). By contrast, showers that stay on tend to eat through much more water.
Melted ice from ice chests was partially diverted to an evaporative cooler.
Grey systems were hidden away from the road to deter poachers dumping and peeing in it.
Make it fun. A grey system that is artistic and consistent with your camp's theme may have more chance of being used in future years rather than being abandoned in favour of expensive pump-out services. Eg. a penguin water slide for a penguin camp, a clothes line of dripping clothes for a clothing camp, a fountain...
Recirculating infinity showers can be just a sump pump: 1, shower with new water. 2, swap out new water again to rinse off. 3, flush out the system for the next person.
Bucket coolers are also good grey evaporators.
Grey water gets extra yucky after sitting for a few days. Chlorine or similar treatments can help.
Buckets sitting in the sun or wind may have too much internal convection for effective floculation.

The pump in action during prototyping:

https://youtube.com/shorts/PgwdrtISpZs?feature=share

The final design explained after field trials:

https://youtu.be/GkrQHU8bifE

Supplies

Sterilization

Hot tub chlorine 'shock' powder

Tank materials

Pond liner (10x13 feet)
Four 8 foot 2x4s (for pond liner frame)
Four 2 foot 2x4s (legs for the frame)
Four ratchet straps (for torsional rigidity and anchoring)
Four lag bolts with 2 link chains (ground anchors)
Wire coat hangers for clips to hold pond liner onto frame
Wood screws and driver

Evaporation unit materials

Aquarium pump with 4 foot head
Mosquito net material
Frame with 8 inch opening and 2 inch thickness (a square frame made of 2x2s)
4 foot 2x2 to hold up hose
3 foot hose
Fans

Grey water collection

Bucket under sink
Mosquito net on bucket to filter out big chunks (t-shirt material clogged)

Backup speed-evaporation system

Leaf blower or pressure washer (leaf blower is especially helpful for speed drying pond liner etc before packing)

Low tech contingency items

Large evaporation pond materials
Inflatable swimming pool for containment
2 buckets per camp member to haul out greywater

Fancy stuff

Floculation system
Filters
Solar lights for tripping hazards (don't fall in the yucky pond)

Step 1: Primary and Backup Systems

We only ended up using the first three items on this list and the leaf blower was mostly for funsies when everything else was already packed up.

1-A 7x7x1 foot containment pond that doubled as a small evaporation pond.

2-A small pump that circulated onto a layer of mosquito netting, a two inch gap, and another layer of mosquito net. This was to break the water apart into small drops for enhanced evaporation. It was sort of like a non-clogging mist nozzle. Three fans drove air through this mist.

3-A $20 Craigslist leaf blower as a nuclear option.

4-A small paddle wheel on the end of a rod driven by a floor fan to throw water in the air and blow it away.

5-An 8x20 foot pond on standby.

6-An inflatable swimming pool as backup containment.

7-The crew of 23 people brought two buckets each to haul out grew water if necessary.

8-And we could have hired a pump-out service if necessary.

Step 2: Pond/Tank

Build a frame to hold your pond liner. Roll the liner around the frame and clip it in place with bend coat hanger. Dig small holes for the vertical posts of your frame so they don't get kicked out by a drunken stumble. Triangulate with ratchet straps. Ratchet strap the frame down to lag bolts. Don't have pokey screws jabbing your pond liner.

Dig out a divot so you can have a low spot where your pump intake will be.

Step 3: Evaporation Unit

Theory: Sprinkle water in small drops with a non-clogging method (no cloggy misting nozzles). Blow air through drops to increase evaporation if needed.

Practice:

Pump water up 2~3 feet
Stretch two layers of mosquito mesh on a frame separated by a 1.5 inch gap break up stream of water into a spray of small drops.
Place mesh frame about 1 foot below water output.
Experiment with water angle. Notice that a solid laminar flow of water will not break apart through the mesh. But water directed upward may break into turbulent drops which do break apart upon impact with mosquito mesh.
Place fans around spray area to increase air flow for evaporation.
Dig out a low spot for pump intake so the pump can access most of the water without sucking air.
Sprinkle in a bit of hot tub chlorine to keep the funk at bay.