[labnetwork] pH neutralization system

[Kuhn, Jeffrey G]

Hello Dr. Eugene,

Welcome to labnetwork!

At Birck, we have a neutralization system consisting of three treatment tanks, each with its own set of pH probes and chemical pumps. We use dual pH electrodes in each tank, one in service and one in standby in case the lead electrode fails. Tank 1 has a capacity of 1,500 gallons, and Tanks 2 & 3 hold 1,000 gallons each. On average, we process about 12,000 gallons of wastewater per day, or about 500 gallons per hour. The majority of influent comes from the UPW system (RO reject, softener regeneration, etc.). The rest is obviously from fume hoods, process equipment, and facility equipment. Influent passes through each tank in series and therefore has three opportunities for neutralization. A final set of pH electrodes monitors the effluent leaving the facility and controls a valve that can automatically close to prevent out-of-spec water from being discharged. All parameters are monitored by our building control software and appropriate personnel are notified automatically if there is a problem.

We currently have no restrictions on the type or amount of acids or bases being introduced to the neutralization system, but that was not always the case. As built, the system was seriously lacking in certain areas and those shortcomings caused issues for some of our users, especially when it came to quartz tube cleaning. It took several hours for them to drain a three-gallon tank of Piranha. That slow draining rate was necessary in order to prevent the Piranha from overwhelming the chemical feed pumps of the neutralization system. That lengthy drain time often caused spots on their quartz ware and necessitated a re-cleaning.

Over the years, we have made numerous improvements to our neutralization system that have virtually eliminated the problems we experienced initially. If you are in the design stages, or if you would simply like more details, please feel free to email me directly and I would be happy to help.

Best Regards,

Jeff Kuhn
Facility Engineer
Birck Nanotechnology Center
Purdue University
1205 W. State St.
West Lafayette, IN 47907
Ph:  (765) 496-8329
Fax: (765) 496-2018
kuhn1 at purdue.edu<mailto:kuhn1 at purdue.edu>


From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Lino Eugene, Dr
Sent: Thursday, July 09, 2015 9:57 AM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] pH neutralization system

Dear All,

I've just joined the labnetwork mailing list and it is my first e-mail.

I would like to know what kind of neutralization system is installed in your fab and its capacity (volume, flow).

Is there any restriction for certain acids (nitric, Piranha mixture)?

Do some of you dispose of acids and bases in waste containers? If so, which acids do you dispose of in the same container or separately?

Thanks,
_______________________________________________________________________________
Lino EUGENE, Ph.D., Jr. Eng.
Research assistant
McGill Nanotools - Microfab

Mcgill University
Rutherford Physics Building - Room 016
3600 University Street
Montreal (Quebec) Canada
H3A 2T8

Phone : 514 398 7329
Fax : 514 398 8434
E-mail : lino.eugene at mcgill.ca<mailto:lino.eugene at mcgill.ca>
Website : www.mcgill.ca/microfab/

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