Case Study - Orange Juice Factory

Challenge:

A Florida orange juice concentration plant was experiencing dramatic biofouling accumulation in the cooling tower serving a taste evaporator. Carry-over of nutrients from the evaporator entered the water-cooling system through a barometric condenser causing biofouling buildup. The issue was first addressed by treatment with chlorine and bromine, but was not successful. Chlorine dioxide proved slightly effective, but was determined too costly due to the cooling tower system’s high oxygen demand. Mexel was brought in for testing for its potential to address the fouling in an innovative and economical manner.

Treatment:

The circulation rate of the cooling water system was 4,800 gpm with a volume of 28,000 gallons. A dosage rate of 4 ppm for 20 minutes daily was chosen by Mexel to effectively treat the system. During the trial, the client allowed the system’s concentration to approach 16 ppm.

Results:

Within hours of the initial treatment, substantial clumps of biomass became dislodged from the towers internals and were found floating in the basin. After three weeks of Mexel treatment, an estimated 75% the cooling tower’s biofouling had been dispersed. It was determined that an equilibrium had been established - the biofouling growth rate was equal to the rate of clearing. It was further noted that the remaining deposits were loosened to such a degree that manual cleaning was successful. After the success of this initial test it was determined that Mexel would both continue and be extended for the treatment of the factory’s water-cooling systems.