WASTEWATER
By Rick Lallish
When conducting a sludge settleometer test, what does the first 5 minutes of the test indicate?
A. Presence of filaments
B. Particle collision rate
C. Presence of zoogloeal matter
D. No useful indication
Answer: D. The settled sludge volume after 5 minutes of settling in the settleometer is an indication of how fast the sludge is settling. The first 5 minutes the sludge is in a free-fall state, with only a few collisions of floc particles to slow it down (Eckenfelder and Melbinger, 1957). This is in a typical settleometer analysis, and there may be a few exceptions. This will help operators or lab personnel
