<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 12 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Wingdings;
panose-1:5 0 0 0 0 0 0 0 0 0;}
@font-face
{font-family:Wingdings;
panose-1:5 0 0 0 0 0 0 0 0 0;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0in;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0in;
margin-right:0in;
margin-bottom:0in;
margin-left:.5in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.hoenzb
{mso-style-name:hoenzb;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";}
span.EmailStyle21
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:902720027;
mso-list-type:hybrid;
mso-list-template-ids:-1533105502 67698689 67698691 67698693 67698689 67698691 67698693 67698689 67698691 67698693;}
@list l0:level1
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:Symbol;}
@list l1
{mso-list-id:1135834400;
mso-list-type:hybrid;
mso-list-template-ids:1088343616 67698689 67698691 67698693 67698689 67698691 67698693 67698689 67698691 67698693;}
@list l1:level1
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:Symbol;}
@list l1:level2
{mso-level-number-format:bullet;
mso-level-text:o;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;
font-family:"Courier New";}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Robert,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Based on your description of the airstream entering your scrubber, you should not have this problem - but obviously you do. I have a few questions and comments:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Your conductivity setpoint of 5000 uS concerns me for two reasons:<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l1 level2 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Courier New";color:#1F497D"><span style="mso-list:Ignore">o<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Assuming your make-up water conductivity is around 750 uS (typical for the Midwest), then you are running between six and seven cycles of concentration.
That creates a lot of nutrients in the scrubber sump that bacteria can use to grow and multiply. The 7.5 to 9.5 pH you mention is a good operating range, but is also ideal for bacteria growth under those conditions.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l1 level2 lfo1">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Courier New";color:#1F497D"><span style="mso-list:Ignore">o<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">If you are using high-hardness potable water for sump make-up (again, typical for the Midwest), then you will almost certainly create scaling on the
scrubber packing as the calcium and magnesium precipitate out. This scale will eventually decrease the airflow through the packing by clogging the air paths and will result in a gradual increase in your exhaust fan speed as it tries to maintain your static
pressure requirements. <o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">My biggest curiosity lies in where the bacteria are coming from. Are there any BSL hoods tied into the scrubber, or are there any other biological
agents that could be “seeding” the sump?<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Is there any way that free acids, bases, etc. could be getting into the sump? Typically, the small amount of fumes from lab hoods should not cause
a rapid change in pH or conductivity.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Is your pH and conductivity instrumentation calibrated routinely? Conductivity instruments tend to be relatively stable but pH instrumentation should
be calibrated monthly – even more often if history indicates that it is necessary. pH electrodes should be replaced at least annually.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">When you drain and refill your sump, what conductivity and pH numbers do you see initially and how rapidly do they change?<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Are you certain that the scrubber is of sufficient size to handle the load (CFM, static pressure, face velocity, etc)?
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I’d like to make the following recommendations as a starting point:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Measure the conductivity of your make-up water, then set your blow down to maintain the sump at 3X that value initially. Run that way for a while
and see how it impacts the problem.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Verify that your pH and conductivity instrumentation has been calibrated and replace the pH sensor if it has aged beyond a year or so.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Audit your system for the possible introduction of liquids or other materials from sources other than the fume hoods.
<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">If you do data collection through Siemens, Johnson Controls, etc., trend the fan operation to see if it is speeding up over time with no additional
demands being placed on the exhaust (an indication that fouling is occurring).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">If you try these things, please let us know if there are any improvements.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Good luck!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1F497D">Jeff Kuhn<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Facility Engineer<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Birck Nanotechnology Center<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Purdue University<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">1205 W. State St.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">West Lafayette, IN 47907<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Ph: (765) 496-8329<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Fax: (765) 496-2018<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu]
<b>On Behalf Of </b>Robert Pollina<br>
<b>Sent:</b> Tuesday, November 27, 2012 7:37 AM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [labnetwork] Fwd: Requesting expertise/ experience with Scrubber by-products in Fab.<o:p></o:p></span></p>
</div>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:.5in">
Struggling with Scrubber equipment and sending e-mails! Hope you saw this e-mail Michael and Jeff.<o:p></o:p></p>
<div>
<p class="MsoNormal" style="margin-left:.5in">---------- Forwarded message ----------<br>
From: <b>Robert Pollina</b> <<a href="mailto:rpollina@umich.edu">rpollina@umich.edu</a>><br>
Date: Mon, Nov 26, 2012 at 7:50 AM<br>
Subject: Re: [labnetwork] Requesting expertise/ experience with Scrubber by-products in Fab.<br>
To: Rizik <<a href="mailto:rizik@intengr.com">rizik@intengr.com</a>><br>
<br>
<br>
Michael,<o:p></o:p></p>
<div>
<p class="MsoNormal" style="margin-left:.5in">Thanks for the reply.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in">I will provide some details of our operation.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"> The five gallons of by-product I mentioned refers to a yellow-brown skin of Fusarium fungus and Negative Rod bacteria that forms on the surface of the recirculating tank. This material forms, grows and clogs
the spray heads and pumps in the system. This material is removed by hand each day.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"> The ph of the water in the recirculating tank is maintained between 7.5 and 9.5. The ph is controlled with a ph sensor in the tank and an automated Sodium Hydroxide (50% solution) feed pump system. A constant
flow of fresh "city provided" water is maintained at 1/2 gallon per minute to make up for evaporation.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"> We use this Scrubber system to scrub the acidic fume hood exhaust air from our labs. <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"> A conductivity sensor helps to maintain a solution that can efficiently deliver the desired result.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"> A manual "blow-down" valve adds fresh water to the system while ejecting old tank water to the drain to assist in maintaining a conductivity reading below 5000u.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in">The Scrubber tank is completely drained and refilled each week as total dissolved solids always exceeds the ability for a quick blow-down to lower conductivity to a good level after 5-7 days of lab operation. <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in">An in-line strainer collects the same material and is cleaned daily.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"> I hope this furthers your understanding of our equipment (Harrington Scrubber) and procedures. Looking forward to hearing from you, let me know if more info is needed<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"><span class="hoenzb"><span style="color:#888888">-Robert.</span></span><o:p></o:p></p>
<div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:.5in">
<o:p> </o:p></p>
<div>
<p class="MsoNormal" style="margin-left:.5in">On Sun, Nov 25, 2012 at 9:44 AM, Rizik <<a href="mailto:rizik@intengr.com" target="_blank">rizik@intengr.com</a>> wrote:<o:p></o:p></p>
<div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Please try to answer the following questions before we provide our recommendation:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">1.</span><span style="font-size:7.0pt;color:#1F497D">
</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Daily removal of 5-gallons of concentrated solution - Do you mean caustic solution? If yes, what is the concentration?</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">2.</span><span style="font-size:7.0pt;color:#1F497D">
</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Is NaOH injection to the recirculating water stream being controlled by a pH Controller to maintained a predetermined pH level?</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">3.</span><span style="font-size:7.0pt;color:#1F497D">
</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">What are you trying to scrub?</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">4.</span><span style="font-size:7.0pt;color:#1F497D">
</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">What is the makeup water flow rate?</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">5.</span><span style="font-size:7.0pt;color:#1F497D">
</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Doe you control Total Dissolved Solids in the recirculating water? If yes, is it controlled by a TDS sensor & controller?</span><o:p></o:p></p>
<p style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">6.</span><span style="font-size:7.0pt;color:#1F497D">
</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">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?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Rizik Michael, PE</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Principal</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Integrated Engineering Services</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Office: +408 261 3500, Ext. 201</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Cell: +408 718 0927</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
<a href="mailto:labnetwork-bounces@mtl.mit.edu" target="_blank">labnetwork-bounces@mtl.mit.edu</a> [mailto:<a href="mailto:labnetwork-bounces@mtl.mit.edu" target="_blank">labnetwork-bounces@mtl.mit.edu</a>]
<b>On Behalf Of </b>Robert Pollina<br>
<b>Sent:</b> Wednesday, November 21, 2012 5:32 AM<br>
<b>To:</b> <a href="mailto:labnetwork@mtl.mit.edu" target="_blank">labnetwork@mtl.mit.edu</a><br>
<b>Subject:</b> [labnetwork] Requesting expertise/ experience with Scrubber by-products in Fab.</span><o:p></o:p></p>
</div>
<div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
Good morning,<o:p></o:p></p>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
I maintain the exhaust Scrubbers serving our wet-benches and fumehoods here at the Nanofabrication Lab at the University of Michigan.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
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.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
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.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
I'm hoping someone has experience with this same equipment and unwanted Fusarium growth.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
How do we better control production of this by-product? What are the proper safety procedures for maintenance staff?<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
Are there other issues I am not aware of concerning this equipment, its operation, maintenance and safety? <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
Any assistance in this matter would be greatly appreciated.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
Robert Pollina<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
University of Michigan<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
Electrical Engineering and Computer Science<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:.5in">
Nanofabrication lab<o:p></o:p></p>
</div>
</div>
</div>
</div>
</div>
</div>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
</div>
</div>
</div>
</div>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
</div>
</body>
</html>