Water Usage
Background
This diagram shows that normal osmosis occurs at atmospheric pressure until equilibrium is reached. to reverse osmosis you apply pressure to the brine side.
The applied pressure is your normal water pressure, the brine solution is your household water.
The yellow area is a semipermiable membrane. this diagram does not show a drain.
The Concentrate in this picture is actually your drain water. A membrane is not a filter. A filter has one in and one out. if this membrane only had 1 in and 1 out the “stuff” in you water we want to remove would clog up the pores of the membrane very quickly. Being a this part is expensive we want to get decent life out of it.
So, How Much Water Do they Use?
The way the membrane life is prolonged is by draining out the concentrate. Every reverse osmosis manufacturer will claim a 4 to 1 ratio. This means for every 1 gallon of drinkable water, 4 gallons will go down the drain. This is true for all systems at atmospheric pressure. Atmospheric pressure suggests we’re collecting our drinking water into a bucket.
Be we’re not collecting it in a atmospheric bucket, we’re putting it into a bladder tank.
As a bladder tank fills it puts a back pressure on the membrane. If your feed water is 60 psi and the tank is empty it will have a 4:1 ratio. but as that tank fills it will build pressure up to 40 psi where it shuts off.
As the back pressure increases (tank fills up) the waste water ratio changes. from 4:1 to 8:1 to 12:1 all the way to 20:1. for that last cup of water before the systems shuts off it will drain 20 cups of water.
If you are a 2 person household how many times have you used 3 gallons of water during a meal? maybe you’ll use 1 gallon maximum. This means you’re usually only working off the top third of the tank. your ratio will be somewhere between 10:1 to 20:1. So for every 2 gallons of water you will use per day the system will drain 20 to 40 gallons of water.
How do we achieve a true 4 to 1 ratio?
The Hague H3500 Reverse Osmosis system has a permeate pump that uses the drain line water pressure to force water into the holding tank. We achieve up to 300% less water waste, and much better pressure.
Essentially the permeate pump creates the same scenario as if we were collecting the water into a bucket. the membrane doesn’t have the same back pressure problem with a conventional reverse osmosis system. So if you’re using 2 gallons of water per day our system will not use more than 8 gallons. That’s 4:1 ratio regardless of how much water is in the bladder tank.
This sounds great but how does it work?
Anyone can make a claim, we can back it up. This is our permeate pump cutaway picture. The drain water and drinking water are separated by the diaphragm in the middle. As drain water enters the pump it actuates the diaphragm to pump water into the holding tank under higher pressure. There are check valves on the tank side to keep the back pressure off the membrane.
Permeate Pump
Because we are pumping water into tank we can achieve a much higher pressure in the holding tank.
Benefits of permeate pump
- Refrigerator water dispenser flows MUCH faster
- Ice maker problems minimized because of low pressure
- Filling a pot for boiling food is faster
- Multiple faucets become possible
Once you’ve had this kind of pressure out of a reverse osmosis system, anything else is ridiculous.