In industrial cooling systems, poly-aluminum chloride (PAC) often triggers foam due to microbial growth or chemical interactions. A chemical plant observed 90% foam coverage in oxidation ditches during low-temperature seasons, with SVI rising to 350 mL/g, causing operational disruptions.
Root Cause Analysis:
Seasonal microbial proliferation: Microthrix bacteria increased surface tension.
Chemical incompatibility: Residual dispersants reacted with PAC, stabilizing foam.
Solution with Chemi Tech Defoamer KM-406:
Emergency defoaming: Sprayed at 50–200 mg/L, rupturing foam within 30 minutes.
Long-term control: Daily dosing at 0.5‰ to disrupt biofilm.
Results:
Foam reduced by 95% in 3 hours, SVI decreased to 120 mL/g.
No foam recurrence over 7 days, demonstrating stability in high-salinity environments.