Real time determination and monitoring of biofilm in cooling systems
HydroBio® Advance, Cooling system, Biofilm, Biocide consumption
This case study shows how the application of the HydroBio® Advance is used to evaluate the real biocide demand of a cooling system in the petrochemical industry. Independent of the season the cooling system in a refinery was treated with the same amount of biocide during the whole year. Nevertheless from time to time high microbiological counts and biofilm formation were detected in the cooling system.
Industry: Petrochemical Plant
Type: Open cooling system
Volume: 3,000 m³
Recirculation rate: 9,000 m³/h
- Save and reliable system operation
- Evaluation of the real biocide demand
- Prediction of biofilm growth
4. ACTIONS / APPROACH
Starting in January a HydroBio® Advance System was installed in the cooling water line to monitor biofilm activities in the system water.
Due to the cold weather conditions the “Biofilm elevated” approach was chosen. This set up even allows a prediction of the biofilm formation by using an elevated temperature profile on the sensor surface vs the cooling water.
With this an early warning can be given if biofilm starts to form and corrective actions can be initiated before biofilm formation in the real system takes place.
With the current treatment in place no biofilm formation did occur in the system. After stopping the biocide treatment completely, almost immediately the biofilm started to grow significantly (Graph 1).
After restarting the biocide dosage at ¼ of the original dosage too much biomass had accumulated so an extra dosage with ½ of the standard dosage had to be carried out. Together with the regular reduced dosage this was enough to keep biofilm formation under control (Graph 2).
As a result it was possible to reduce the total biocide consumption by 35% during the winter time (25% all over the year) in order to keep biofilm formation under control.