Grey water is the water that doesn't contain feces type waste in it. The water comes from your washing machine, kitchen sink, shower and bathroom sink. The greatest percentage of contaminants in grey water comes from the soap that was used to clean whatever the water was washing when it was being used.

I've manually recycled unfiltered grey water from my washing machine by watering my trees and lawn with it to see if it has any effect. With over a year of doing this and only once in awhile giving the trees and grass clean, fresh water the plants seem to be quite healthy.

I've proven to myself (somewhat) that the grey water won't hurt the plants or trees but I'd still like to take some of the contaminants out of the water before giving it to my plants just so that they don't have to deal with so much of it.

While I know that Sand Filters will not take out all the contaminants, I believe that it would help a lot. Sand filtration would especially be helpful if the water might be stored for short periods of time before it's used.

Sand Filters are great for filtering large amounts of water in short periods of time so I thought about purchasing one. I found out quickly that Sand Filters are not as cheap as I though and I need a more economical solution than buying one.

The principles of a Sand Filter are very simple - water goes through the sand and the sand picks up all the particles that are in the water leaving it clarified. A Sand Filter works a lot the same way water is clarified in nature.

A Sand Filter driven by gravity should be easy to build out of some common things we can purchase for fairly cheap.

I'm going to use the following items to make a High Capacity Gravity Driven Sand Filter:

• Plastic 200 Liter Drum with clamped, removable top.
• About 2 feet of 4" White PVC Tubing
• About 2 feet of 1-1/2" White PVC Tubing
• Various PVC Fittings
• A few square feet of Wire Screen
• About 150 liters of low cost river sand.

My plan is to fill the drum about 3/4 full of sand. I'll cut a hole in the bottom for the piping to fit into and be clamped into place with gaskets to stop it from leaking. The 4" PVC will be perforated with small holes that are about 1/16" in diameter. The end of the PVC pipe that's inside the drum will be capped and filled with wire screen. The outside end of the 4" PVC will be reduced to 3/4 inch, the reduction will hold in the wire screen and allow for a regular sized garden hose to fit onto it.

However, before I go all out an build a sand filter I need to know that the expense and time will be worthwhile and that it's performance will be as I imagine. I'm going to do some simple column tests to see just how much of the contamination, that can be identified visually, will be taken out by sand filtration.

My Sand Filter Column Test Will be as Follows:

Sample 1 - I will filter 20 liters of water through a 3 foot long 2" diameter PVC tube that is screened on the bottom with the first (dirtiest) rinse from my laundry machine.

Sample 2 - I will take another 20 liters of water from the same rinse cycle and not filter it at all.

Usually the rinse water from a washing machine will grow a thin, gross looking film over the surface within a few days in the climate that I live in so I will allow both of the samples to sit outside, in open containers for two weeks or as long as it takes to see a noticeable difference.

I will take regular samples and record the difference between the sand filtered water and the unprocessed water to see if a sand filter has some effect on taking out some of the contaminants before reusing grey water.

Of course - I'm going to take pictures of the samples and share all my results with you. If anybody wants to sponsor labratory testing of the water leave me a note in the comments.

Shopping Result: 

Hayward S166TPAKS Pro Series Top-Mount Sand Filter 16-Inch with Top-Mount Valve and Base

Manufacturer: Hayward

Part Number:

Price: $393.30