Elgressy EST: Chemical-Free Scale, Corrosion and Biofouling Control for Cooling Towers

Cooling towers and chillers lose efficiency to three constant enemies: scale, corrosion and biofouling. Conventional treatment fights them with a steady supply of anti-scalants, corrosion inhibitors and biocides, at a recurring cost and with chemical handling, storage and discharge to manage.

Elgressy EST (Electrolysis Scale Treatment) takes a different approach. Developed by Elgressy Engineering Services, this patented technology uses controlled electrolysis to treat cooling water without chemical additives. This article explains how EST works, the benefits for your plant, and the questions our customers ask most.

How Elgressy EST Works

EST is installed as a side-stream system: a portion of the circulating cooling water flows continuously through EST reaction chambers and returns to the tower.

1. Controlled electrolysis: inside each reactor, a DC current flows between coated titanium anodes and the cathode, using the cooling water itself as the electrolyte.
2. Scale precipitates in the reactor, not in your system: at the cathode, water is split and hydroxide ions (OH⁻) form, raising the local pH. Calcium and magnesium hardness precipitate there as solid scale, instead of on condenser tubes, heat-exchanger plates and pipes.
3. Automatic scale removal: the collected scale is periodically removed from the reactor and discharged, so hardness leaves the system for good.
4. Biofouling control: at the anode, oxidising species are generated from the chlorides naturally present in the water, inhibiting bacteria, algae and biofilm.
5. Corrosion protection: with clean, deposit-free surfaces and no aggressive chemical dosing, metal surfaces stay protected and under-deposit corrosion is prevented.

Key Benefits of Elgressy EST

• Chemical-free: no anti-scalants or corrosion inhibitors to buy, store, handle or discharge, safer for your people and the environment.
• Water savings: removing hardness allows the tower to run at higher cycles of concentration, significantly reducing blowdown and make-up water.
• Energy savings: clean condenser tubes keep the chiller’s approach temperature low and compressor energy use down.
• Low corrosion: Water Treatment Asia guarantees a maximum mild-steel corrosion rate of 2 mpy with EST.
• Less maintenance and downtime: fewer acid cleanings, tube brushings and unplanned shutdowns.
• Longer equipment life: chillers, heat exchangers, cooling-tower fill, pipes, valves and pumps are protected from scale, corrosion and biofilm.
• All-in-one: one system addresses scale, corrosion and biological fouling together.
• Real-time monitoring: performance data lets you track your water system continuously.
• Fast return on investment: savings in chemicals, water, energy and maintenance typically pay back the investment quickly.

Sizing and Installation

EST is modular. Systems are configured from standard reactor units, such as the EST-N 25-3-25, to suit cooling systems from around 500 TR up to 50,000 TR. Because EST is installed in a side stream, it can be added to existing cooling towers without changing the main circulation system, and it has a small footprint.

Frequently Asked Questions

How does electrolysis create the conditions for scale removal?

A DC current passes from the anodes through the water to the cathode. At the cathode, water molecules are split, producing hydroxide ions (OH⁻). The resulting local rise in pH makes calcium carbonate and other hardness minerals precipitate on the cathode, where they are collected and removed.

Can EST be used in any industrial water system?

EST is designed mainly for open recirculating cooling towers and related industrial cooling-water systems. Suitability depends on your system type and water quality. We start every project with a water analysis to confirm the right configuration.

Do the anodes dissolve into the water?

No. The anodes are coated titanium, designed to withstand the electrical current without dissolving, so they do not add metals to your cooling water.

How does EST relate to the Langelier Saturation Index (LSI)?

The LSI indicates whether water tends to form scale (positive LSI) or to be corrosive (negative LSI). Cooling water operated at high cycles is usually strongly scale-forming. EST makes that supersaturated hardness precipitate inside the reactor instead of on your heat-transfer surfaces, so the system can run at higher cycles without scaling.

How does EST control biofouling?

Oxidising species generated at the anode inhibit the growth of bacteria, algae and biofilm. Because surfaces stay free of scale, microorganisms also have far fewer places to attach and grow.

Related Reading

• Calcium Carbonate (CaCO3) Scale in Heat Exchangers
• Legionella in Cooling Towers: Risks, Warning Signs and How to Prevent It
• Carbon Steel in Cooling Systems: Types, Properties and Corrosion Control
• LEED Certification Explained: Levels, Credits and How Cooling-Water Treatment Helps

Ready to Go Chemical-Free?

Water Treatment Asia has been the exclusive distributor of Elgressy EST in Southeast Asia since 2010. Contact our team with details of your cooling system and water quality, and we will prepare a free assessment and savings estimate for your facility.