ICP vs. Reverse Osmosis

Reverse osmosis wasn't built for cooling water. ICP was.

Both technologies clean water — but they work in opposite ways. Reverse osmosis forces water through a membrane under high pressure. ICP, the MIT-patented process behind NONA RECOVER, pulls the minerals out instead, so there's no membrane to foul and up to 90% of your cooling water comes back.

Reverse Osmosis

  • Forces water through a membrane at hundreds of PSI
  • Membranes scale, foul, and need replacing
  • Rejects a concentrate stream you have to dispose of

ICP (RECOVER)

  • Pulls minerals aside with a low-pressure electric field (~3 PSI)
  • No membrane for water to pass through, so nothing fouls
  • Recovers up to 90% — eliminates blowdown

Confirmed in in-lab testing: ICP runs at room temperature and ~3 PSI — and was co-developed with the U.S. Army.

Short answer

Ion Concentration Polarization (ICP) is an MIT-patented, electrochemical alternative to reverse osmosis. Reverse osmosis forces water through a membrane at hundreds of PSI, leaving that membrane to scale and foul. ICP instead applies a low-voltage electric field at roughly 3 PSI and room temperature to pull dissolved minerals out of the water — so the water never passes through a membrane to clog. For industrial cooling, that lets NONA RECOVER reclaim up to 90% of the water a cooling tower would otherwise dump as blowdown.

ICP is the technology behind NONA RECOVER for data-center cooling-water recovery and broader cooling-tower water recycling.

Most water treatment technologies were designed for a different era — when water was cheap, energy was cheap, and cooling towers ran simple. Reverse osmosis works by forcing water through a membrane at high pressure. It's effective, but it brings fouling risk, high energy draw, and complex chemical management. Ion Concentration Polarization works differently.

The mechanism

How ICP works

ICP uses an electric field applied across a narrow channel to push dissolved ions — the minerals that make blowdown water unusable — away from the water stream. The result: purified water on one side, a concentrated reject stream on the other. No membrane contacts the water flow, so there's nothing to foul. No pressure pump is needed, so there's no energy-intensive high-pressure system to maintain.

Think of it like cleaning water with an electromagnet. The minerals respond to the electric field; the water does not.

How ICP works

Reverse osmosis pushes water through a membrane. ICP pulls the minerals out of it.

Reverse osmosis forces water through a fine membrane at high pressure, leaving the membrane to scale, foul, and clog. Ion Concentration Polarization — invented at MIT — never sends the water through a membrane at all. Here is what happens inside a RECOVER skid.

01

Apply a small electric field

RECOVER runs your cooling water past ion-selective membranes and applies a low-voltage electric field — at roughly 3 PSI and room temperature, not the hundreds of PSI reverse osmosis demands.

02

Pull the dissolved minerals aside

The field creates an ion concentration polarization zone that pushes dissolved salts and minerals to one side of the flow — like cleaning water with an electromagnet rather than forcing it through a filter.

03

Split into clean and concentrated streams

The flow divides into a demineralized stream and a concentrated stream. The water never has to pass through a membrane, so there is no membrane surface to foul or replace.

04

Return clean water to the loop

The demineralized water goes straight back into your cooling loop, recovering up to 90% of it — so you stop dumping blowdown and stop buying makeup water.

Head to head

ICP vs. reverse osmosis vs. thermal

Operating pressure

Nona ICP
~3 PSI
Reverse Osmosis
Hundreds of PSI
Thermal
Heat-driven (not pressure)

Energy requirement

Nona ICP
Low
Reverse Osmosis
High (high-pressure pump)
Thermal
Very high

Fouling risk

Nona ICP
None (no membrane contact)
Reverse Osmosis
High (membrane fouling)
Thermal
Low

Chemical pretreatment

Nona ICP
Minimal
Reverse Osmosis
Significant
Thermal
Minimal

Water recovery rate

Nona ICP
Up to 90%
Reverse Osmosis
50–70% typical
Thermal
Varies

OpEx

Nona ICP
Low
Reverse Osmosis
Moderate–High
Thermal
Very high

Retrofit complexity

Nona ICP
Low (side-stream unit)
Reverse Osmosis
Moderate
Thermal
High

ICP vs. reverse osmosis: common questions

Straight answers for engineers comparing Ion Concentration Polarization to reverse osmosis for cooling-water recovery.

What is ICP (Ion Concentration Polarization)?

ICP — Ion Concentration Polarization — is an electrochemical water treatment process invented at MIT that uses a small electric field to pull dissolved minerals out of water, splitting the flow into a clean stream and a concentrated stream. Unlike reverse osmosis, the water never passes through a membrane, so there is no membrane to foul. NONA's RECOVER system uses ICP to recover up to 90% of industrial cooling water on-site.

How is ICP different from reverse osmosis (RO)?

Reverse osmosis forces water through a fine membrane at high pressure (often hundreds of PSI), and that membrane scales, fouls, and needs regular replacement. ICP instead applies a low-voltage electric field at roughly 3 PSI and room temperature to move minerals aside, so the water never crosses a membrane. The result: no membrane fouling, far lower pressure, and a process that tolerates the cooling-tower chemistry RO struggles with.

Does ICP use membranes that need replacing?

No. ICP uses ion-selective membranes to set up the electric field, but the cooling water never passes through them the way it does in reverse osmosis. There is no filtration membrane for minerals to clog or foul, which removes the recurring membrane-replacement and cleaning cycle that drives RO operating costs.

What pressure and temperature does ICP run at?

ICP operates at roughly 3 PSI and room temperature. Reverse osmosis typically runs at hundreds of PSI, which is why RO systems are energy-intensive and hard on equipment. The low-pressure, ambient-temperature design is a core reason RECOVER has low operating cost.

Will ICP work with my existing cooling tower chemistry?

Yes. ICP is fouling-tolerant and compatible with the corrosion inhibitors and biocides already running in your cooling towers, so there is no rip-and-replace of your water-treatment program. RECOVER bolts onto your existing cooling loop and lets you run higher cycles of concentration instead of dumping water to control mineral buildup.

How much cooling water can RECOVER actually recover?

RECOVER recovers up to 90% of your cooling water. A single 10 MW data center's cooling system consumes roughly 230,000 tons (about 60 million gallons) of water a year, and 20–50% of it is typically dumped as blowdown. RECOVER continuously demineralizes that water so it keeps circulating instead of going down the drain.

Does RECOVER replace my evaporative cooling?

No — RECOVER works with the evaporative cooling you already run, which remains the cheapest and most efficient way to reject heat. Rather than switching to dry or adiabatic cooling that costs roughly 1.9–2.3x more, RECOVER recovers the water your evaporative system would otherwise lose as blowdown. It is an add-on to your loop, not a replacement for your thermal design.

Is ICP proven, and who is using it?

ICP was invented and proven by NONA's founding team at MIT, and its development was funded by the U.S. Army for field water production where reliability and low maintenance are non-negotiable. NONA's first industrial RECOVER pilot is running today with Tracy Renewable Energy, recovering cooling water on a working site.

Is there an alternative to reverse osmosis for cooling water recovery?

Yes. Ion Concentration Polarization (ICP) is an electrochemical alternative to reverse osmosis, invented at MIT and commercialized by NONA in the RECOVER system. Instead of forcing water through a high-pressure membrane, ICP applies a low-voltage electric field at roughly 3 PSI to pull dissolved minerals aside. For the high-conductivity chemistry of cooling tower blowdown, that means no membrane fouling, lower operating cost, and higher recovery than membrane systems typically reach.

What recovery rate can reverse osmosis achieve on cooling tower blowdown?

Membrane-based reverse osmosis systems are typically capped around 75–85% recovery on high-conductivity cooling tower blowdown — beyond that, dissolved minerals begin to scale the membrane and the system has to reject the rest as waste. ICP is not limited the same way: because the water never crosses a filtration membrane, RECOVER recovers up to 90% of blowdown on-site and returns it to the cooling loop.

How much can RECOVER lower water use and operating cost versus reverse osmosis?

RECOVER can cut a facility's make-up water demand by up to 50% and lower water-related operating cost by up to 40%, because it recovers up to 90% of cooling tower blowdown and lets you run higher cycles of concentration. It runs at roughly 3 PSI and room temperature with no membrane-replacement cycle, so it avoids the pump energy and membrane cost that drive reverse osmosis OpEx.

Does ICP work at data center scale?

Yes. RECOVER is a modular, side-stream system that scales with your cooling load. A 150 MW data center consumes on the order of 120 million gallons of water per year for cooling (EPRI, 2025), and 20–50% of a tower's throughput is typically dumped as blowdown. RECOVER tees into the blowdown line to recover up to 90% of that water without changing how the towers run.

Sources & references

ICP was invented, peer-reviewed, and patented at MIT, and its development was funded by the U.S. Army. The figures on this page trace to the primary sources below.

See what ICP recovers that reverse osmosis can't.

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