Water Environment Federation (WEF) Discussion Forums / WEF Discussion Forums / Laboratory Management & Technical Issues

RE: Autoclave calibration

Victor — Sun, 11 May 2008 10:11:26 GMT

Mark:

Market Forge sells a continuous temperature recorder for the SterilMatic part no. 95-2606 (120 V). I installed one for the autoclave here in the micro lab after ELAP recommended one. You can view Market Forge's Price List PDF on this particular autoclave:

http://www.mfii.com/products/healthcare/sterilimatic/sellsheet/PDF/s3220.pdf

Autoclave calibration

Old lag — Tue, 04 Dec 2007 14:00:10 GMT

As part of our ISO17025 requirements, our auditor wants us to calibrate our autoclaves annually. The calibrating company has to have certified pressure and temperature measuring equipment. Does anyone know of anyone who can run these tests? Preferably Midwest. All the ones we have talked to have measurement equipment but it is not traceable to NIST or some recognized standard.

RE: Autoclave calibration

wodamark — Sat, 10 May 2008 06:50:53 GMT

Thanks for the info on maximum temp thermometers. We have been using them all along.

The need is for the ability to measure the temp of an autoclave run so as to ensure that the required minimum temp is maintained during it. Std Methods wants the max/min recorded once a week.

RE: Incubator for BODs

Egadz — Fri, 09 May 2008 14:52:03 GMT

Too bad you couldn't repair it. Ours went out awhile back and instead of replacing it at great expense we found out what had gotten burnt out by lightning and fixed it for less than four hundred dollars.

Egadz

Incubator for BODs

PLFB — Mon, 24 Mar 2008 14:08:58 GMT

We came into work this morning and found our incubator out of temperature range by about 5 degrees. Obviously, it is equipment failure. Thankfully, we have two 20 cubic foot incubators just for this purpose.

Does anyone know what is the general replacement time for a BOD Incubator? I really do not have any idea as to how long they should last. I thought that both of the incubators we have were purchased in 2000 or 2001, but it appears that the one that is not working was older than that. The condenser appears to have been worked on before. It is a Precision 815, and the lead time for a new one is 13 weeks. I can have a Barnstead model in 2 weeks. I am not as familiar with those incubators though. Any thoughts on the Barnstead incubator?

I am not exactly sure as to how long the BODs were at this higher temperature, since the alarm did not go off. I have a feeling that there is also an issue with the controller as well.

As for the BOD samples I moved them over to the working Incubator and decided to read them back anyway. I know the data will not be good, but I am curious to see if the results.

Thank you for any input,

Patti

RE: GC Question

jackb — Thu, 08 May 2008 15:32:40 GMT

Running a blank right before the ccv might raise a problem with some auditors and data validators because you are treating the ccv differently than your analytical samples. They probably would not have a problem with running a blank after every sample, but who wants to do that.

Jack

GC Question

NBuske — Wed, 07 May 2008 09:29:07 GMT

We are performing PCBs in oil and are having difficulty recovering CCVs after running these particular samples. Any help would be appreciated. And if there exists a forum better suited for GC analysis questions, I'd be glad to know. Thanks.

RE: GC Question

Christopher Fair — Thu, 08 May 2008 12:19:51 GMT

Scap's recommendations are also good. To take running through the temperature program once without an injection one step further you can do a high temperature for some period between injections. This combined with solvent only can really go a long way to straightening out a bad baseline.

RE: Biosolids -fecal coliform testing

bsims — Thu, 08 May 2008 12:16:12 GMT

Our laboratory used to run this analysis for our organization's compost facility. My advice to you would be to run. Run away as fast as you can. This test requires too much work for too few results. It's very labor intensive, the QC is a pain in the you-know-what, and overall, it is just a time-waster when you consider everything else that has to be done in a laboratory. I commend you for trying to take this on, but a small lab, especially a one-man operation, would probably be better off subcontracting the sample to a large commercial laboratory. In my opinion, There is too much tedious b.s. involved with this procedure for a small operation to be able to do it in a cost-effective manner.

Biosolids -fecal coliform testing

scap — Fri, 25 Apr 2008 15:48:44 GMT

I need to start testing our biosolids for coliform. I plan on using EPA 1680. Please help this overworked lab tech in a one man WWTP lab by providing me with info about where to purchase culture tubes, durham tubes, media etc...

Are there any premade systems out there which will spare me the time of preparing, sterilizing and setting it all up by hand?

Thank's!

RE: Substances Oxidizable by Permanganate

Christopher Fair — Thu, 08 May 2008 11:14:20 GMT

I know of a method that does this and expresses the value as "COD" chemical oxygen demand. If you look in the Hach Water Analysis Handbook 4th edition on page 751 there is a method for Manganese III oxidation there. Years ago this was how chemical oxygen demand was first performed, now dichromate is the norm. The problem I see that you might have is whether or not you want to heat the sample or not. Does your client want the compounds that are oxidizable at a particular temperature? There will be a significant difference in the amount of oxidizable material found at room temperature and at 150 degrees. You could also make a standard KMnO4 solution then titrate an aliquot of the acid with it at room temperature. When the oxygen demand of the sample is exhausted you would have a slight purplish color in the water solution. You could then calculate the amount of oxygen that would equate to. Anyway, there is a method for this, but it is adapted as a substitute for COD. You might be able to do this test without any heating whatsoever. Feel free to email me if you would like some help developing a simple test for this.

Substances Oxidizable by Permanganate

Keith Hoover — Thu, 08 May 2008 09:46:28 GMT

I'm looking for a reference or procedure for "Substances Oxidizable by Permanganate" or "Substances Reducing Permanganate". We are testing sulfuric acid per a customer's specs. The only method I've found is a presence/absence test in an old Merck book, but the spec is "5 mL max", so I need something quantitative.

RE: Autoclave calibration

Sabir — Thu, 08 May 2008 00:17:40 GMT

I agree with David. Find the further details on this link;

http://hbinstrument.thomasnet.com/viewitems/thermometers-special-application/autoclave-thermometer?&plpver=10&forward=1#

RE: GC Question

scap — Wed, 07 May 2008 13:14:03 GMT

Chris is correct, the liner is almost always to blame for recovery problems. It is the first place I look.

Are the recoveries consistently high, consistently low, or just inconsistent?

If you repeat injection of the CCV does the recovery come back into range? This may indicate carryover from the previous sample affected the first CCV run.

A drifting baseline can cause intergration problems which result's in an improperly integrated chromatogram. Try running a blank after the sample and before the CCV to allow the GC to cycle through its temperature program once.

RE: Biosolids -fecal coliform testing

scap — Wed, 07 May 2008 12:55:11 GMT

F coliforms Part II

In method 1680 the CFU/ml of the Ecoli spiking solution is calculated by plating the spiking solution and counting colonies after incubation.

Is there some reason I couldn't just use Colilert to enumerate the spiking solution? Do you think this is a allowable modification per the Part 136 regs?

RE: GC Question

Christopher Fair — Wed, 07 May 2008 12:20:55 GMT

Is this the PCB analysis where you add concentrated sulfuric acid to the tube then cap and shake for the clean up step? It has been years since I did that analysis. If I am remembering correctly we had some trouble doing them and had to replace our inlet liners quite a bit with them. If you are using the pre-prepared liners try preparing your own. You can buy the inlet tubes then take glass wool and use the silanizing agent on it and the tubes directly. After silanizing just pour off the excess reagent then dry the tubes in a 105 degree oven overnight. When we had troubles with recovery it was almost always the liners that gave us problems. Like I said it was years ago, so if this isn't too helpful I am sorry, I thought I would take a crack at it since nobody else had yet.

Distillation Comparability Studies

Keith Hoover — Wed, 07 May 2008 11:34:13 GMT

Is there an EPA document on the procedure and specifications for distillation comparability studies (e.g., Ammonia)? If so, what's the link? I know some states have their own documents. I'm not looking for opinions, I'm looking for EPA guidance documents on the subject.

RE: Autoclave calibration

dsmith — Wed, 07 May 2008 11:11:07 GMT

Get a shakedown maximum temperature thermometer. It will stay at the highest temperature acheived until shaken down.

RE: Autoclave calibration

wodamark — Wed, 07 May 2008 09:31:57 GMT

What device (make/model) do folks use to comply with SM 9020 B 3 h for recording the maximum/minimum temperature of the autoclave.

By the way we have two Market Forge Sterilmatics that are old but still work like champs

RE: Zeroing spectophotometer for COD analysis

Ducky0219 — Tue, 06 May 2008 15:22:23 GMT

I have always zeroed the spec with the digested blank, for both methods - low and high range. Never had a problem with the calibration curves doing it this way.

Zeroing spectophotometer for COD analysis

Clem — Fri, 02 May 2008 17:50:19 GMT

Our lab is developing a colorimetric procedure for detemination of chemical oxygen demand, after many years of titration. We are using Hach tubes containing digestion reagents, and a Hach DR 5000 spectrophotometer. My question regards the proper means of zeroing the instrument absorbance prior to calibration.

The information from Hach suggests the instrument should be zeroed with a digested blank (which I would consider a method blank). Standard Methods 5220 D suggests zeroing with deionized water. For some other procedures (e.g., total phosphate) we have been zeroing with a mixture of digestion solution and deionized water (some would call it a reagent blank, although others hold that a reagent blank can contain no matrix - i.e., no DI water).

Any feedback, opinions, or information regarding what your labs are doing would be helpful. Thanks.

RE: Prison Strength

Dvant — Tue, 06 May 2008 14:37:45 GMT

Terry and John,

Thanks for the replies.

Mark

Prison Strength

Dvant — Mon, 05 May 2008 18:01:22 GMT

What is the average BOD and TSS from a prison. We have been getting 380mg/l BOD and 342mg/l TSS and a flow of 0.24mgd.

For many years the prison has been given price breaks because they were trying to bring down their loading, but now we are holding them to the rate structure. BOD $0.70/lbs, TSS $0.80/ lbs and flow (748 gallons) $0.80. Every one in town had their rate double, but the prison trippled because they had never paid the full price.

So, anyone think the BOD or TSS numbers are out of line? Also, the prison runs a commercial laundry that takes in flour sacks now and then.

Depending on what numbers are used to calculate domestic loading, the prison produces the loading of 5000 people, but...there are only 1600 inmates.

Long story short, I think we are fair, they don't.

TKN Digestion

diatomguru — Tue, 06 May 2008 14:08:33 GMT

I am trying to find information on how to perform a digestion for TKN using an autoclave. Can anyone tell me if this is possible? Any information is greatly appreciated.

Thanks,
Andy

RE: Prison Strength

John Sansalone — Tue, 06 May 2008 13:34:15 GMT

Have dealt with several prisons and similar institutions over the years, and would not be surprised by any particular loading. Problems observed include: decisions to shut down pre-treatment (bar screens), so that all sorts of stuff comes down the pipe - kitchen wastes such as oranges and peelings, etc; even with screens, loadings of plastics (the little packets that condiments come in); in one case, involving a youth center (read: reform school) the entire influent pipe was jammed for 10 feet, with bunched up sheets (the game is that the "clients" would try and cause their room to flood, just to bust the horns of the guards, and force them to move them to a new room); large spikes in flow, since everyone eats, showers, etc., at the same time.

The prisons have also often gone to ultra-low flush toilets, which removes a lot of dilution from the BOD and solids. Another factor to consider is whether or not there are any other "industrial" processes taking place - whether it is stamping out license plates, wood shops, other vocational training, etc. Some have their own farm operations, to supplement the diet, so there may be food processing as well. You'll need to talk to someone in administration, to find out.

Hope this helps some.

RE: Prison Strength

TerryF — Tue, 06 May 2008 07:24:44 GMT

Tchobanoglous and burton in 1991 rated prison hydraulic load as 80-150gal /day per inmate and 5-15 gals per day per staff member.BOD per capita should be in the normal range of 0.11-0.26 lbs /day /capita notwithstanding the issue of the flour bags. This should allow you to some claculations.

Regards

TerryF

Ammonia loss during block TKN digestion

Suenoir — Mon, 05 May 2008 13:10:19 GMT

We are using a FOSS tecator to digest TKN. We use 25 mL sample with 10 mLs digestion reagent. The digestion is 1hr @ 160 raising to 380 over one hour, then 30 minutes at 380.

We run a 20 ppm NH4Cl standard and a 25ppm Urea standard. We get about 18ppm recovery of the NH4Cl standard and 22 recovery for Urea. Our TKNs are lower than the ammonias on the same samples sometimes.

Any suggestions would be welcome.

RE: Zeroing spectophotometer for COD analysis

dsmith — Mon, 05 May 2008 08:21:21 GMT

First off, you have to notice that SM gives you two methods for analyzing COD. The first and most common is what you are using now that goes from about 50-100 up to about 1000mg/L COD. Use an undigested blank as your zero initially. SM says that once you determine your MB to be consistently clean you can use a digested blank as your zero.

The part you see that says to use reagent water as your blank is for the low level reagents. You measure this one at 420nm, as opposed to 600nm, and the curve is backwards from what you expect. The color will actually get lighter the higher the concentration. This one has a range of 10-150 mg/L of COD.

For everything, except low level COD's, we zero with a true method blank carried through the entire analytical procedure.

Tri-Counties Section of CWEA Workshop

Victor — Fri, 02 May 2008 15:00:56 GMT

The Tri-Counties Section of California Water Environment Association (which serves the Santa Barbara, Ventura, and San Luis Obispo Counties) is having its Treatment Plant of the Year Training Workshop 12 June 2008 in Simi Valley, CA. For further details view attached PDF. Personally, I think it is one of the best deals for your buck!

RE: Standard Methods Joint Editorial Letter Acknowledging that EPA has Approved LDO and the it can be used with SM5210B

Christopher Fair — Wed, 30 Apr 2008 13:03:28 GMT

I hope this doesn't constitute advertising because I don't want to do that, but on the Hach Website there is a very useful map that helps you find out the status of your state. There is also a packet available for requesting approval in states where approval has not been granted yet. To get the packet for your state you just click on your state on the map.

http://www.hqdmeter.com/epa/epa.htm

Standard Methods Joint Editorial Letter Acknowledging that EPA has Approved LDO and the it can be used with SM5210B

iWater — Fri, 25 Apr 2008 15:00:28 GMT

The following was posted by Standard Methods at http://www.standardmethods.org/ViewArticle.cfm?articleID=70.

Please note: Although the LDO® method developed by the Hach Company is not currently approved by Standard Methods for determining dissolved oxygen, either as a stand-alone procedure or as part of the Standard Methods BOD procedures, USEPA has approved the LDO® method for 40 CFR 136 compliance monitoring via the Alternative Test Procedure (ATP) program. See the attached memo from USEPA dated April 14, 2008 for specific details of requirements to use the ATP protocol. Standard Methods hopes there has been no misunderstanding within the user community regarding compliance testing that may have arisen out of these circumstances.

This should take care of the confusion out their in the regulatory community!

RE: Standard Methods Joint Editorial Letter Acknowledging that EPA has Approved LDO and the it can be used with SM5210B

Christopher Fair — Wed, 30 Apr 2008 12:55:57 GMT

I will try and find out for you. I don't don't remember which one won't accept the LBOD outright. So far I don't think there are any that won't let you use it if you do a side by side study for them first.

RE: Fisher-Scientific XL60 benchtop meter

labrat — Wed, 30 Apr 2008 12:08:58 GMT

thanks Sue! Orion 4 or 5 Star was really the next in line. I'm gonna try and find out the deal w/ the Hach LDO procedure for acceptance in my region and go from there. I don't wanna spend all my $ and then find out I could've got the LDO instead for DO.

Fisher-Scientific XL60 benchtop meter

labrat — Wed, 23 Apr 2008 09:22:03 GMT

Does anyone have any good/bad to say about the XL60? I am in the market for a new benchtop meter - and it is between this and the Orion 5 Star. The only problem w/ the 5 Star is the DO probe. Does the YSI 5010 fit into the XL60?

Thanks!!

RE: Standard Methods Joint Editorial Letter Acknowledging that EPA has Approved LDO and the it can be used with SM5210B

labrat — Wed, 30 Apr 2008 12:05:32 GMT

ok, folks. Which region isn't willing to accept LDO? Why don't you wanna say?

RE: Standard Methods Joint Editorial Letter Acknowledging that EPA has Approved LDO and the it can be used with SM5210B

P. Brake — Tue, 29 Apr 2008 22:17:39 GMT

That's exactly my point, Chris. HQ EPA leaves it up to the individual regions to approve use of LDO, and at least one of them (which I won't name) requires each NPDES permittee to submit an ATP approval request to show that for their wastewater, LDO and currently approved DO measurement methods provide essentially identical data. Bureaucracy at its best!

Perry

RE: Standard Methods Joint Editorial Letter Acknowledging that EPA has Approved LDO and the it can be used with SM5210B

Christopher Fair — Tue, 29 Apr 2008 16:37:24 GMT

P. Brake (4/25/2008)

As much as I wish the April 14 memo were HQ EPA's approval to use LDO, I don't read it that way. I see it as HQ EPA encouraging ALL of the EPA Regions to follow the lead of those that have gone to the effort of approving ATP requests for limited use of LDO. It's beyond my understanding why EPA can't just issue a one sentence memo..."Use of LDO is allowed for NPDES compliance testing...period" I know...I know...that's too easy...

Perry

It is a little better than that. The ATP has already been accepted by HQ EPA. The underlying data is already available and can be submitted to any EPA region that has questions. IN MOST cases all a user should have to do is say they are going to use it. There is at least one region that is refusing to accept the data and is requiring additional data from the user. That is a real shame because the study was an interlaboratory one. In Colorado we have had some submit the data to local regulators along with the letter from the EPA and they were granted a go ahead right away. As you can imagine this is a real headache for us. We can't give straight answers because we really can't get straight answers to give.

RE: Hach DPD free chlorine powder pillows

wing — Tue, 29 Apr 2008 15:53:55 GMT

Thank you Thank you Thank you!! That's exactly what I wanted to hear.

Hach DPD free chlorine powder pillows

wing — Mon, 28 Apr 2008 11:12:54 GMT

I was curious if the free chlorine reagent contains anything to prevent interference from monochloramines. All I saw on the MSDS was a lot of "trade secret". Our water plants use chloramines and I don't know if we can trust our handheld colorimeters in the field when looking for free chlorine.

Thanks

Wing

RE: Hach DPD free chlorine powder pillows

Christopher Fair — Tue, 29 Apr 2008 12:21:28 GMT

So long as the reading is taken quickly monochloramine will not interfere at all. There is a very slight interference (<0.10 mg/L) if your monochloramine concentration is 2.5 mg/L or higher if the reading is delayed longer than about 30 seconds from addition of the powder. There is also a powder pillow for measuring only monochloramine and one for measuring ammonia if you need that information.