Reverse Osmosis Water Project

[apostolakisl]

OK, this is not exactly what this forum is about, but I think people here would find it interesting.

I picked up a 55 gallon polyethylene drum from our local home brew store for $10 (and washed out the malt extract). I put another $10 into a garden hose spigot which I drilled and tapped into the bottomish part of the drum. I picked up a RO system from Costco for $140 and a small float valve on ebay for $7. I drilled a hole in the topish area of the drum and mounted the float valve. Finally I got a 100ft garden hose from HD for $30.

I hooked all this stuf up and put in the corner of my garage. It took two days but the RO finally filled the 55 gal drum filled.

Now, I plug the hose into my pressure washer and have RO water via pressure washer. I can now wash the car, house windows, or anything I want to air dry without water spots. I got so excited I washed all the house windows and both cars. Between the 100ft of hose and the 50ft of pressure hose I can just barely get all the way around the house. Shockingly, it only used maybe 20 gallons of the tank and I felt I was pretty generous on my rinse cycle. I did not use RO water to wash or do the initial rinse, just the final rinse.

Everything dried damn near perfectly spotless. There were a few VERY faint spots that you could see if you looked just right and the sun was shining just right. But, 99.9% of people asked the question, "is that window spotless" would say, yes.

 

[Photon]

The Watts Premier manual states, "There is an average of 4 gallons of reject water for every 1 gallon of product water produced." Have you found a way to put the water rejected from the RO system to use? Water the garden? Use for the first phase of the car wash/window wash before the final rinse with the filtered water? It would take four more drums to capture what is otherwise wasted, but it might be worth the additional expense.

 

[apostolakisl]

Yes, I was aware of that. I have septic and the waste water goes into the field, so it is basically watering the grass. From a cost standpoint, my water bill is based on a minimum of 5000 gallons/mo. I typically only use 3500, so the extra water is "free".

From a quantity standpoint it isn't going to end up being that much anyway. Washing all of my windows and the car only used about 20 gallons, meaning maybe another 100 gallons of waste. Since this is probably only a once a month thing, I am not that concerned about 100 gallons.

The pressure washer is rated at 3.8gpm 4000 psi. So I guess that means that I ran 5 minutes worth of rinse. I am pretty sure I did more than 5 minutes worth of rinsing however. I suspect that it is not pumping 3.8gpm becuase of the lack of input pressure. The water is only under the pressure of gravity. The tank is on the floor in the garage, which is higher than anywhere I would park the pressure washer, but not by much. When I just let the hose free-flow, it comes out with hardly any force. I had feared that it wouldn't work at all and that I was going to have 55 gallons of RO water in my garage waiting for a nuclear holocost or something to be of any use. But the pressure washer is able to "drink" the water just fine and provide a lot of gpm and pressure, but I wouldn't be surprised if it is only half of its rated capacity.

 

[heffneil]

I have a whole home reverse osmosis and we originally changed it to store the waste water to another tank. When it reaches a certain level I then water the bushes around the perimeter of the property (I didn't want yard sprinklers to open up at random times.) It works well but I replaced the system with multiple RO membranes so I actually filter the run off water and get less waste! Works well but isn't inexpensive to do because it is about twice the system. The good water is stored in one tank and the run off in another. Let me know if this helps with ideas!

Thanks,

Neil

 

[potts.mike]

Maybe I don't understand RO Systems well enough but doesn't the waste water have a higher concentration of salts and such in it? is the concentration enough that in time watering with it could be an issue?

 

[signal15]

Do you have a separate pump supplying your pressure washer with pressurized RO water? If you're doing gravity feed to get the water into your pressure washer, there is a high likelyhood that you are going to wreck the pump unless it has been specifically designed to be able to take non-pressurized water.

Most pumps are not, and will cavitate, which will eventually ruin the pump.

 

[heffneil]

I have a well pump that pumps the water up from the well and through the two membranes. I then have a pump in each of the two tanks. The good water tank is switched by a pressure switch for the house. The "bad water" or run off from the RO system has a two float system with a high float and low float. The high float kicks the pump on and the low float turns off that pump. This is a single switch with two switches and imperative to make sure the water is pumped down and not running too often and for short spurts.

I am not sure what pressure washer you are referring to or if the question was even aimed at me Reading back it doesn't look like it was aimed at me RO waste water for washing anything seems like a bad idea to me!

Thanks!

Neil