Closed system cooling water treatment

At the Vorwerk company in Preljina, we began treating the cooling water in the closed-loop machine cooling system in May 2025. The system is complex, with various construction materials coming into contact with the cooling water. The system contains components made of steel, aluminium, copper and stainless steel, making it extremely demanding in terms of treatment and corrosion control.

Before the treatment began, corrosion coupons for all four construction materials were installed, and the corrosion rate and deposit formation were monitored. This monitoring was also continued during the treatment.

The water treatment was carried out using technology from NALCO Water, An Ecolab Company:

• NALCO TRAC102 corrosion inhibitor
• NALCO 77352 non-oxidising biocide

The system was monitored monthly, with water analyses and corrosion coupon evaluations being carried out.

Now, after more than a year of treatment, it is time to flush the system and summarise the results:

Before treatment

1. Deposits and corrosion damage were visible on the corrosion coupons before the corrosion inhibitor was dosed.
2. The corrosion rates of the most sensitive materials were:
   1. Aluminium: 0.22 mm/year
   2. Steel: 0.55 mm/year
3. Positive biological fouling test results
4. Clogging of the mechanical filters in the system

During treatment

1. No visible deposits on the corrosion coupons
2. Corrosion rate of 0.00 mm/year on all coupons
3. Negative biological fouling test results
4. No filter clogging