Alleima stops using biocides in cooling system

There are multiple challenges associated with the operation of an open recirculating cooling system. Warm water temperatures and evaporation drive bacterial growth and accumulation of solvents. Significant additions of chemicals, including biocides, are needed to handle Legionella risks and issues with corrosion, scaling and biofouling. Increasing awareness of Legionella and biocide risks has led to a need for alternative solutions.

In order to phase out biocides, Alleima Tubes in Sandviken has installed AquaWorker - industrial UV for process water. 

Biocide-free and 90% reduced costs

The installation of AquaWorker at Alleima cooling system resulted in several important improvements:

  • A biocide-free cooling system
  • Reduced operating costs with more than 90%
  • Less handling of chemicals and related risks
  • Low and stable bacteria levels below recommended action levels
  • Reduced risk of Legionella outbreaks to the surrounding environment
  • Less chemicals in waste streams to meet environmental legislations

Read the full case here [PDF]

Focus on sustainability at Alleima

At Alleima Tubes, part of the continuous environmental work is to reduce the use of chemicals. For the furnace cooling system, the objective was to replace the use of biocides with UV treatment to control microbiological activity. The benefits are multiple; biological control, reduced OPEX, reduced health hazard risks of personnel and environment and waste stream compliance.

Cooling system without biocides

For the cooling system at Alleima Tubes, Wallenius Water Innovation made a system analysis based on cooling capacity, system volume and water analysis. In addition, factors such as operational parameters and installation point with presumed greatest effect was considered. One AquaWorker was installed and in full operation in September 2023. Since October 2023, the cooling system has been in operation without the use of biocides. Water samples have regularly been analyzed for bacteria activity.

Annual savings of 14 000 euro

Alleima's total annual savings amounted to 14 000 euro. The calculations include costs for biocides, electricity, spare parts and maintenance hours by personnel. The main savings are due to reduced consumption of biocides.

 

Biocides only

AquaWorker in operation

System data

Total volume=20 m³, Cooling flow rate=140 m³/h, Operation=330 days, 16h (not during nights))

Water treatment

Biocides 100% 

UV treatment (no biocides)

Biocide dosage

2 times/week

-

Bacteria levels

Bacteria levels below 104 CFU/ml

Bacteria levels below 104 CFU/ml

Transmittance of water

11-35% (filter damaged)

80-85%

Water/system appearance

Dirt, flakes, foam

Clear water

Want to know more? Read the full case here [PDF]