Particle Characterization in Environmental Applications
Membrane Integrity Testing
Task: Characterize a breach to a membrane filtration system during operation through highly sensitive particle detection and enumeration.
Sample: Filtered water spiked with 4µm micro-spheres to a concentration of 10,000/ml and pumped through a submerged hollow fiber membrane with nominal pore size of 0.04µm.
Run Conditions: The filter effluent was sampled continuously for 150 minutes. The membrane filter was breached at 15 minutes by cutting a single fiber.
Analysis: The particle count increased from 32±9.7 particles/ml to 491±89 particles/ml when one fiber was cut. The theoretically expected count was 500/ml. A conventional laser particle counter recorded 1.44±0.20 particle/ml and 3.42±0.62 particles/ml respectively.
