A permeate pump increases the efficiency and productivity of a reverse osmosis system. Without a permeate pump, a reverse osmosis (RO) system dispenses a lot of water to the drain and produces clean water at a slower rate. John Woodard, our Master Water Specialist, tells you how this RO water pump can improve your reverse osmosis system.

What is a permeate pump?

permeate pump

A permeate pump is a device that, applied to a reverse osmosis (RO) system, actually allows that system to work at its highest efficiency. It saves a lot of water to the drain, making the system very efficient. It also enhances performance. The reverse osmosis system creates a higher quality of water a little bit faster when it has a permeate pump on it.

What is RO reject water, and what is permeate water?

RO reject water, permeate water, concentrate, product flux-- there are many different terms for the same few things. Reverse osmosis separates the water into two pathways. You have a membrane, and as water is forced against that membrane, some of it will permeate through. That's the good water. That's the reverse osmosis water. We refer to it as permeate.

You'll also hear people talk about product water. The other rate in which it runs through that membrane is referred to as flux. The water that carries the contaminants to the drain, that doesn't permeate through, that's called concentrate. It's also referred to as reject water. Some people even call it brine. And our permeate pump labels the inlet and outlet for that drain water as the brine in and out.

How does a permeate pump improve a reverse osmosis system?

A permeate pump improves a reverse osmosis system's efficiency. Efficiency refers to the amount of water going to the drain compared to the amount of water collected in the storage tank. A reverse osmosis system is it uses a hydro-pneumatic storage tank. There's water on one side of a bladder or diaphragm and air on the other side. Water only compresses a little. Air, on the other hand, does compress. As this tank fills with water, the diaphragm pushes down into the air chamber and compresses. That air compression is the energy or the force that pushes water out of the tank when we open the faucet to fill a glass. This process fights against the reverse osmosis system, but the permeate pump stands in between the two to make the RO system more efficient.

Learn more about how a permeate pump works with a reverse osmosis system.

How do permeate pumps work?

Permeate pumps collect water headed to the drain and use that energy to push the permeate water collecting on the other side into the storage tank. As the concentrate or drain water collects inside, it activates a piston that pushes the water into the tank. That process keeps that pressure tank from pushing back on the membrane's production, and that's what makes the system more efficient.

How does the permeate pump differ from an RO booster pump?

A permeate pump and an RO booster pump differ because they do two totally different things. A booster pump, just like it sounds, boosts water pressure to allow the reverse osmosis system to work better. We have to have a certain amount of pressure against the membrane to cause the process to work in the first place. Some installations don't have enough pressure, so a booster pump allows the membrane to function properly because it has plenty of driving force. It doesn't do anything else but boost pressure.

The permeate pump, on the other hand, doesn't boost pressure but allows the membrane to work much more efficiently. The greatest efficiency saving water that would dispense to the drain without it. It also enhances the quality of water that's made, and it enhances the speed at which it's made. The difference between the two: a booster pump boosts pressure, while the permeate pump enhances a system's performance and makes it much more efficient.

Learn more about how booster pumps work.

How do you install a permeate pump?

You install a permeate pump by putting the permeate line through one side and installing the brine or the reject waterline on the other side. The reject water powers the permeate pump. It causes the permeate to get pushed into the storage tank. The waterlines install right behind or right after the membrane. The membrane's permeate outlet is typically where you're going to hook the permeate line up, and the drain line is going to go through the other side, which is labeled "brine in" and "brine out." 

Some, but not all, reverse osmosis systems easily let you apply the permeate pump. Manifold systems-- compact and with three tubing or four tubing connections-- may not allow the permeate pump to hook up easily. The permeate pump act as a check valve. It can only flow water in one direction. In most manifold systems, water has to go into the tank and back out of the tank on the same line. So you'd have to bypass the postfilter to be able to install this.

If you have questions about your reverse osmosis system and whether or not a permeate up will hook up to it, give us a call and we'll walk you through the process. For any water quality concerns talk to a water specialist at 864.284.1801.

Visit our blog to learn how to select the best reverse osmosis system and troubleshooting tips.


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