[labnetwork] Requesting expertise/ experience with Scrubber by-products in Fab.

[Robert Pollina]

Good morning,

  I maintain the exhaust Scrubbers serving our wet-benches and fumehoods
here at the Nanofabrication Lab at the University of Michigan.
Exhaust air passes through our Harrington Scrubber where Sodium Hydroxide
solution is sprayed over a "whiffle-ball-like" material, and a favorable PH
is reached before the air is vented to atmosphere.  The NaOH solution is
collected in a lower tank and recirculated to the spray heads. PH sensors
and Conductivity sensors call for more NaOH and city supplied fresh water
as needed.

  Problem: Large amounts of Fusarium , Negative rod and Rototurula
bacterias and fungi are created in the tank and must be removed to keep the
Scrubber operating properly. This by-product is removed almost daily, often
exceeding five gallons of concentrated solution.

  I'm hoping someone has experience with this same equipment and unwanted
Fusarium growth.
How do we better control production of this by-product?   What are the
proper safety procedures for maintenance staff?
Are there other issues I am not aware of concerning this equipment,  its
operation, maintenance and safety?

  Any assistance in this matter would be greatly appreciated.

Robert Pollina
University of Michigan
Electrical Engineering and Computer Science
Nanofabrication lab
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