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

[Rizik]

Please try to answer the following questions before we provide our
recommendation:

 

1.      Daily removal of 5-gallons of concentrated solution - Do you mean
caustic solution? If yes, what is the concentration?

2.      Is NaOH injection to the recirculating water stream being controlled
by a pH Controller to maintained a predetermined pH level?

3.      What are you trying to scrub?

4.      What is the makeup water flow rate?

5.      Doe you control Total Dissolved Solids in the recirculating water?
If yes, is it controlled by a TDS sensor & controller?

6.      Does the recirc water go through a periodic purge cycle or does it
continue to circulate and water is replenished only when water level in the
basin drops?

 

 

 

Rizik Michael, PE

Principal

Integrated Engineering Services

Office: +408 261 3500, Ext. 201

Cell:      +408 718 0927

 

 

From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu]
On Behalf Of Robert Pollina
Sent: Wednesday, November 21, 2012 5:32 AM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Requesting expertise/ experience with Scrubber
by-products in Fab.

 

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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