If the two sample volumes are the same, the Weight of the Dry Residue of both the sample and duplicate should fall within 5% of their average.

If the sample and duplicate volumes are not exactly the same, convert the Weight of the Dry Residues from mg/L to g/L:

Weight of Dry Residue mg/L/(Sample volume mLs/1000).

Then compare the two Weight of Dry Residues in g/L to 5% of the average of the two.

This should be indicated somewhere on the benchsheet.

We have had a Systea Easychem instrument for more than 3 years.  I'm happy with it.  Our instrument is an older model and I dont know how it compares with their current instruments or other manufacturers.  We routinely run silica in water and total Kjeldahl nitrogen in wastewater on it.  We occasional use it for ammonia, nitrate/nitrite and nitrite when another instrument is down.

I will PM you my contact information if you would like additional information.

If you're asking in terms of what to report on your discharge monitoring report, I'd reiterate to first read through your permit, and if nothing is there, check with either your lab certification agency &/or permit writer.  Some states have a specific format they want you to use when completing your DMR's.

GSain

I am trying to figure out how to determine MDL's for NH3,NO3 and

TKN's.

For approximately the past 15 years we have been running daily in house COD tests on our effluent. During that time we have been using HACH COD Standard Solution 300 mg/L for QA/QC purposes as it closely matches our typical effluent values. That being said in all the years we have been using this standard it has consistently run high. One would certainly expect to see some variance in the value but I would anticipate it averaging out to close to 300. This has not been the case for us, as our results, with few exceptions, run in the 310-318 range.

In all the time we have been conducting this test we have used 3 separate HACH reactors with each reactor producing pretty well the same results. The HACH DR 2800 Spectrophotometer we currently use for reading is calibrated annually by a HACH representative and continues to produce high  standard values, even immediately following the annual calibration.

To take it a step further I recently produced my own set of standards using stock potassium hydrogen phthalate. I produced standards with concentrations of 200, 500, 1000. 1500, and 2000 mg/L respectively and read the absorbance values of each standard. I then plotted these absorbance values and produced a linear line of best fit resulting in an R2 value of 0.9996 (this was expected as the spectrophotometer should read absorbance values linear up to 2000 mg/L). I then took the absorbance of the HACH 300 mg/L standard and plotted against the line, and using the equation determined the concentration to be 312 mg/L.

Safe to say we are having difficulties pinpointing why the standard does not average closer to 300 mg/L , after all the standard claims to be a 300 mg/L standard. I am wondering if anyone else has run into a similar issue or has any perspective on what our difficulties may be?

Thanks,

Chad G

We all eagerly waiting to see the live version on Youtube.

Merry Christmas to y'all and thanks for the chuckle!

Gary

Concord, NC

OH B-O-D (to the tune of O Tannenbaum)

Oh B-O-D, Oh B-O-D, You are so biochemical

A little sample and then some seed.  So plain yet diabolical

To set you up is such a breeze.  Just five short days at 20 degrees

Oh B-O-D, Oh B-O-D.  Pray the blanks don’t deplete on me.

First get the bottles all lined up.   Then calibrate the meter

Aerate the water; prep the seed.  And don’t forget the Winkler

Pipet your samples in “just so”.  Make sure they have enough D.O.

Now load the samples on a cart.  Incubate them five days in the dark.

If Wednesday morn you put them in.   Next Monday all your woes begin

All the dilutions that you tried.  Were either too low or else too high

All your controls are out of range.  The calculations just too strange

Oh B-O-D you are so great.   The test that we all love to hate

Here is an old Christmas song to warm your hearts:

OH B-O-D (to the tune of O Tannenbaum)

Oh B-O-D, Oh B-O-D, You are so biochemical

A little sample and then some seed.  So plain yet diabolical

To set you up is such a breeze.  Just five short days at 20 degrees

Oh B-O-D, Oh B-O-D.  Pray the blanks don’t deplete on me.

First get the bottles all lined up.   Then calibrate the meter

Aerate the water; prep the seed.  And don’t forget the Winkler

Pipet your samples in “just so”.  Make sure they have enough D.O.

Now load the samples on a cart.  Incubate them five days in the dark.

If Wednesday morn you put them in.   Next Monday all your woes begin

All the dilutions that you tried.  Were either too low or else too high

All your controls are out of range.  The calculations just too strange

Oh B-O-D you are so great.   The test that we all love to hate

Terry,

Sorry for being so late in replying.  We use ordinary Acrodisc from Pall Filters.  We do a filter blank with every run and have had no problems in quite a few years.  Our detection limits are just a little higher than those on your list.

Chuck Lytle,

City of Portland, OR

I'd like to connect with anyone that has issue regarding the subject matter.  Our NPDES permit requires the City to use T. gratilla, a sea urchin to test for the whole effluent toxicity test. Performance is best on how the in lab serial diluted wastewater compares with the controls (NOEC) and a significant difference results in a permit violation if it occurs before the dilution for our outfall.  We have gone through a Toxicity reduction evaluation plan documentation and performed the toxicity identification evaluation. All indications may point to anionic and nonanionic surfactant.  You can drop me an email at cjaramilla@honolulu.gov or call me at 808-768-3253.

Aloha.

CJ

The 18th edition says "adjust pH to 6.5 - 7.5" so somewhere between this and the 21st a change was made.

I am mystified as you.  I would have assumed that the final pH of 7.0 - 7.2 is to make sure the phosphate buffer is not overwhelmed by the use of a strong acid or base, but if that is so then why allow samples to be has high as 8.0 or as low as 6.0.

EPA published a letter stating that the 22nd edition of SM is merely an editorial version of the approved method and issued a national ATP approval.  Since PDF files cannot be attached to these posts, please send me an e-mail if you want a copy of the letter.

However, some have noticed differences in method practices such as the inclusion of MS/MSDs in the BOD method and the incorporation of a change in the incubator temperature reading schedule found in 9020B.

It is becoming apparent that the 22nd edition is not a mere correction of spelling, but potentially significant changes in practice.  It would appear that SM is incorporating the 12 QC elements that EPA first proposed then subsequently eliminated as required in the final Methods Update Rule (the 12 were relegated to option 3 for when a method lacks QC).

From a legal standpoint the letter is merely an ATP approval of the 22nd edition and is an option to the approved method cited in 40CFR part 136.3.  The selection of methods is your choice so be sure you know what you are obligating yourself to do if you select the 22nd edition.

The question - after all of the expose - is what other changes have been made?  Have any of you noticed a difference in method or QC requirements between the approved method and the 22nd edtion version?

You are correct in that it is a comparison between the two residue weights and their average.  The Excel forumla would be

100*ABS(Cell1-Cell2)/(AVERAGE(Cell1:Cell2)*2)

Cell1 and Cell2 are the cells with the residue weights (final - tare)

100 is to covert to percent and 2 is because the comparison is to each weight.

Some may recognize the formula without the 2 factor as the one to compute % difference

This suffers the same problem as all others where the determination is against a fixed value in that there are ranges of weights where the comparison does not make sense.  Below are some actual results and how they fared

WT 1   WT 2   % differece to average

16.7   16.8          0.3

  2.2     3.2        18.5

  3.1     3.3          3.1

  6.5     6.9          3.0

As you can see the second pair compute to an 18.5% difference.  The sample is of a final effluent and 1000mL was sampled.  The only way to improve this would have been to use more sample and collect more residue.

The good news is the wiggle word "should".  "Should" does not mean "Shall" so you can write up a work around.  In these cases, I suggest the "If..then" process where the 5% applies unless some limit is met then another criteria is used.  For example

5% for weights over 5 mg, 1.0 mg for 5 mg or less

The way I read this note is that if the method does not discuss preservation, then  follow this criteria.  Note 2 states "except where noted in this TAble II and the method for the parameter.  The method we use states that samples are to be analyzed within 24 hrs or if held longer, then preserve.  I think you can make an argument that since the method allows 24 hr. holding before preservation, that this superceeds this note.

Both EPA method and Standard Methods say to make up this solution by adding NaOH to a sodium tetraborate solution.

Is there a valid reason for making the sodium tet solution first rather than simply adding the 4.75 g of decahydrate directly to the 1L flask along with the NaOH?

We are a small WW plant lab doing simple stuff such as BOD and SS.  The rest is done by contract labs.  The lab bought HACH WIMMs more than a year ago but did not implement using it.

Does anyone have experience with WIMMs in a small lab enviroment?  Especially using worksheets to calculate results and the importing of EDDs from contract labs?

How do you post a new topic after logging in the the Lab Forum?

This is a strange situation since EPA posted a statement that the 22nd edition of SM was merely an "editorial" update of the actual approved method.  This would indicate that the BOD method is not.

From a legal standpoint the approved method is the one freferenced in the federal regulations and is the one approved byt the JTG in 2001.  Any copy of that is relavent.  Also note that EPA killed the 12 Elements as requirements for QC and relegated them to option number 3 in cases where a method lacks QC (Note that it is not when a method lacks adequate or sufficient QC, but totally lacks QC).

Method 1600 from 2006 requires a matrix spike and precision and recovery studies. 

There were two ways to spike - the seriel dilution method that is tedious and time consuming or use BioBalls - has anyone that uses this method used these BioBalls?

Thanks

We went with the WASP WL S9500.  Reasons:  (1) good compromise between sensitivity and readable distance; (2) uses a cord (we found the rechargeable battery readers to go dead too often);  (3) good service from the company; (4) reasonable cost.

Chuck Lytle,

City of Portland, OR

I asked Standard Methods why there was this difference in the depletion targets for the two methods.  They forwarded my Query to experts within AWWA and this is their response, "In 5210B, oxygen depletes to near stasis conditions for aerobic organisms; in the respirometric test, oxygen is not limited, because air is renewed periodically keeping oxygen levels in a higher range throughout the test.  I don't know of any lab that ever gets consistent GGA results above 220 with 5210B." This answer is quite logical. It does contradict my experience. We used Oxtitops in the past to avoid week-end work.  Our GGA results were higher than the dilution method by a few mg/L but no where near 260 mg/L.

That is what I have been using. I'm also wondering if possibly the flasks are too full of liquid.

Do you use the Labconco Micro-Digestion system? I'm adding 5 g of soil, 50 mL of standard and 10 mL of TKN-reagent. This is for my MDL study.

When I've added only liquid and less than 50mL I don't get the bumping problem.

I would suggest that you discuss the analysis and method with the contract lab. Pick a lab that will do the analysis you want.

Volatile Acids ( Organic acids) is a measure of low molecular weight organic acids such as acetic, propionic, butyric, iso butyric, valeric, and isovaleric acids. Method 5560 should be used. Results are reported as acetic acids normally.

Method 2310 is a measure of inorganic acids as CaCO3 and not the same as VA. Some organic acids might be titrated and add to the total acidity, inorganic acids, though.

2320 is alkalinity.

Worker Bee,

They're all EPA methods.  What you're calling "solid waste" methods come from the EPA compendium known as SW-846, which was written by the EPA Office of Solid Waste for work under RCRA.  What you're calling "EPA" methods come from the EPA Office of Water for use in NPDES and other general environmental work.  Note that the EPA Office of Groundwater & Drinking Water has it's own set of methods, as does the Contract Lab Program for CERCLA/SARA work.

The methods can be very similar, but can have different lists of analytes for which they're approved.  Also, the SW-846 methods tend to give analysts more leeway in applying them, i.e. they're written for analytical chemists.

All of that being said, the various EPA offices tend to be INTENSELY jealous of their territories.  Thus, if you're doing work under any type of NPDES permit, you should review the methods listed in the tables at 40 CFR 136.  (The "okay" drinking water methods are at 40 CFR 141.)  You'll find that the tables at 136 also list methods from Standard Methods, ASTM, and USGS, so the EPA isn't totally rigid.

If you're working at a treatment plant lab, you should get a copy of your permit.  The allowable TYPE of methods should be in there.  For example, we are mandated to use the methods at 40 CFR 136 for domestic and industrial wastewater BUT are required to use SW-846 methods for our biosolids program.

Chuck Lytle,

City of Portland, OR

Now that I have retired maybe I can respond to this issue more quickly.

You need a good seed material that has no nitrifiers and a significant number of bacteria so that any additional amount of seed material will not increase the BOD or CBOD result. Additional seed material will increase the seed correction factor as there are organics in the seed material along with the bacteria. Any nitrifiers in the seed will oxidize nitrogen from the glutamic acid or ammonia from the dilution water.

Running BOD and CBOD on GGA should give the same result as the organic concentration is the same in both analysis.

Lower results for CBOD, in my opinion, can be due to some nitrification in the BOD test or toxicity of the inhibitor in the CBOD test.

Jason,

For our laboratory, all of your areas of interest fall under Civil Service and a collective bargaining agreement between the city and the union that represents the laboratory workers.

We just finished a comprehensive classification/compensation review and update.  For salaries, we used comparable sized, West Coast municipal labs offering similar analytical capabilities, adjusted for cost of living differences.  The COL data came from federal sites on the internet.  We also compared salaries to other position series within the city that had comparable responsibilities.  (The specific skill sets were different because these internal comparisons were between lab and non-lab positions.)  So, our compensation decisions were, in your words, "...defined skill based..."  Because we're a public utility with represented lab staff, performance bonuses, etc. are not allowed.

Productivity benchmarks are pretty much useless because we're not a production lab.  However, we do use performance metrics that are updated and reported to upper management monthly:  gross revenue per FTE (we have an internal charge-back mechanism and also do work for outside agencies via IGAs); supplies as percent of gross revenue (done on a section basis...organics, metals, etc.); percent on-time analyses per section; production overtime (we don't count overtime used to cover holidays and vacations...we're a seven-days-a-week operation); percent gross revenue sent to outside contract laboratories.  Note that these are "business" oriented.

The issue of certifications will take care of itself when we finally apply for NELAC accreditation.  Well, not quite the certification of individuals but at least a demonstration of competency.  When this happens, it will not affect compensation.

Have these been "proven effective over time??"  More or less.  We've used them all to change practices and have been fairly successful in lowering overtime, pulling back in-house a lot of work we used to send out to the contract lab (we do a simple return on investment study if this involves buying a new instrument), and keeping our supplies budget manageable.

Chuck Lytle,

City of Portland, OR

When I last used frozen seed we settled fresh raw sewage, that we had collected during normal flows, and dispensed it in 60 ml plastic bottles. We froze the seed material. We thawed it in luke warm water and setup a series of GGA to evaluate the seed correction and GGA value. We would use this same seed material from 1 to 2 months without haveing any problems or running out of seed. We would collect another batch to settle, freeze, and check before running out of previous seed material.

It is ultimately to ensure that you are comparing apples to apples, or should I say, atoms to atoms.  17 grams of ammonia, NH3 and 101 grams of KNO3 both contain 14 grams of Nitrogen.  Also remember that a part per million in this case is milligrams of Stuff per liter volume of solution. 

I'm not an expert but my experience is and have been told by people who sell the commerical seed, you will eventually fail a GGa with that type of seed. I've been threw it a lot in the last couple of years. Yes, even if your seed factor comes out,  try uping the 6 to 8 in a bottle or two. I was also to by several experts, use your own seed from supernanat from influent or mix liquor, you will get better results.

We are also having problems with the effectiveness of ATU for CBOD.  Interestingly, CBOD results are pretty reasonable for our treated effluent samples, based on parallels with TCMP.  CBOD measured for primary effluent and GGA however, are often the same or greater than the respective BOD’s.  When I checked the forum today I was I relieved to see it isn't just us.  We hope to continue automated addition, thus the need for a soluble inhibitor, but unless we can find a way to get TCMP into solution, we’ll likely go back to adding powdered solid directly to bottles.  I plan to continue to research this and I may also forward this concern to our DEQ regional representatives.   I would appreciate hearing from others who have experienced problems, especially anyone who may have come up with a way around the TCMP solubility issue.

Thanks,

Ron

 Typical British singing/humor.  View Thames Water crew singing in the sewer.  Thanks to Steve for the head's up:

http://www.youtube.com/watch?v=w1rItAH60MU