Non-Chemical Water Treatment for Cooling Towers
The Problem
Where there is a need for cooling water, four factors cause concern for engineers and plant management: Corrosion, Scale, Bio-fouling and Algae. Together, they cause major problems including: Health hazards, increased electricity and water consumption, reduction in cooling efficiency and reduced equipment life expectancy. Until now, the common method of treatment for these problems entailed the use of chemicals which are expensive, environmentally unfriendly and don’t guarantee results.
The Solution
Elgressy`s solution is based on a non-chemical, state of the art, patented technology which prevents scaling, bio-fouling, microorganism growth, inhibits corrosion and produces free oxidants in the water Using a unique electrochemical process the system actively, efficiently and cost effectively deals with the problem associated with cooling tower systems without using harmful chemicals .
Benefits
- Chemical Free Technology
- Huge Savings on Operational Costs
- Huge Savings in Energy and Water Consumption
- Scale, Bacteria and Corrosion Control
- Longer System Lifespan
- No Discharge as drained water is re-usable for irrigation or other.
- Fully automatic, side stream installed, small foot print.
- From single EST 200 TR to MEGA EST 50,000 TR, modular.
- SCADA optional.
- Quick ROI
Cooling Towers Treatment – EST
EST electrochemical systems are revolutionizing cooling tower
treatment by providing a omprehensive and effective treatment against scaling, corrosion and bio-fouling.
Typically, hazardous chemicals are added to the cooling water to inhibit corrosion of system
components, to retard mineral scaling and to limit bacteria growth.
Not sure whether to switch? Read non-chemical vs chemical water treatment compared, learn how chemical-free water treatment works, or check the 5 signs your cooling tower needs non-chemical treatment. Cooling towers are treated with our EST electrochemical system.
How does it work?
The Elgressy EST system treats a side stream of the cooling tower water in electrolysis reactors. A controlled DC current raises the pH at the reactor walls, so calcium hardness precipitates there as solid scale and is removed automatically, instead of depositing on condensers, heat exchangers and fill. Oxidants formed at the anodes control algae, bacteria and biofilm, without chemical additives.
Disinfection
1. An alkaline environment of pH 13 is created next to the reaction tank’s inner walls creating a strong disinfectant. 2. Near the anodes, 3-7% of the naturally present chlorides are converted to free chlorine or hypochlorite (OCl-). The OCl- level is programmable to automatically remain at ~0.1-0.2ppm, providing additional disinfection without the risk of corrosion. 3. Additionally, disinfecting radical oxygen, ozone and hydrogen peroxide are produced near the anode.
Scale removal
The high pH at the reaction tank wall precipitates the calcium (and other cations) on the wall. The EST is capable of precipitating > 30% calcium from the water before it crystallizes into scale, while the remaining calcium is kept dissolved in the water. The calcium precipitation percentage is programmable, automated and varies from project to project. The EST patented scraper system automatically scrapes and flushes the reaction tank to remove the precipitated scale.
Corrosion control
The remaining Magnesium ions in the water prevent corrosion along with controlled operation at a maximum of 2 MPY.
Advantages:
- Cost effective – rapid return of investment
- Solves cooling tower problems stemming from algae, corrosion and scaling
- Reduces maintenance, shut down time and labor cost
- Generates huge water savings
- Chemical free solution –eliminates the need for expensive and harmful chemicals
- Very low life cycle cost and electricity consumption
- Controllable and measurable ensuring consistent quality water
- Small footprint
- Robust and high-quality equipment with few moving parts
- Modular and simple to install or retrofit
- Proven effective in thousands of installations worldwide.
- Environmentally friendly
EST is Modular, so from 200 TR till 20.000 TR and even bigger.




Issues often found at Cooling Towers but NOT when treated with EST
Non-Chemical Cooling Tower Treatment: Frequently Asked Questions
What is non-chemical water treatment for cooling towers?
Non-chemical water treatment controls scale, corrosion and bacteria in a cooling tower without dosing scale inhibitors, corrosion inhibitors or biocides. The Elgressy EST system does this by electrolysis: hardness precipitates as scale inside the EST reaction tank instead of on your condensers and heat exchangers, and is pumped out automatically.
Does non-chemical treatment control Legionella and bacteria?
Yes. Near the EST anodes the water forms oxidants that disinfect it, and the high pH zone at the tank wall prevents harmful micro-organisms from developing. This controls biofilm, algae and Legionella risk without adding biocides.
How does EST protect against corrosion?
EST keeps the water within a stable, controlled chemistry and removes the scale that causes under-deposit corrosion. ALA guarantees a corrosion rate of maximum 2 mpy.
Do we need to shut down the cooling tower to install EST?
No. EST is connected side-stream to the cooling tower basin with its own circulation pump, so no intervention in the main cooling system is needed. This reduces installation cost and time.
What size cooling towers can EST treat?
EST is modular, so it is used on cooling systems from about 200 TR up to 20,000 TR and larger, including data centers, power plants, hospitals, factories and commercial buildings.
What is the return on investment?
Savings come from energy (cleaner condensers and lower approach temperature), water (higher cycles of concentration and less blowdown), no chemical purchases, less downtime and longer equipment life. ALA prepares a site-specific ROI and IRR calculation for every project.
Building for WELL or LEED certification?
See how EST supports the WELL Legionella precondition (W03) and helps earn LEED cooling tower water points.
EST for WELL & LEED buildings →© 2026 Water Treatment Asia, a subsidiary of Aerial Lift Asia Co., Ltd.
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