Water and Wastewater.com Help Forums - Control Tests for NH3-N

whearn11

YaBB Newbies

Offline

I love Water and
Wastewater.com

Posts: 10

Company or Organization: Micron Technology, Inc.

Control Tests for NH3-N
Aug 20^th, 2012, 12:30pm

I work at a electronic manufacturing plant. We operate a pre-treatment facility and discharge to a POTW. We remove fluoride and phosphate with lime. We have ammonia concentration of ~50 mg/L. The plant operators measure NH3-N every six hours. The method is a ISE probe presently, but also have a HACH kit using DR/2010. They have trouble with these methods. Is there a less expensive, easy-to-use, method for analyzing for NH3-N control tests? Our on-site lab analyzes our discharge for compliance, but they don’t analyze the control samples. Is there any help out there?

Back to top

IP Logged

David S.

Senior Member

Offline

I have nothing
clever to say here.

Posts: 373

Gender: male

Company or Organization: Environmental Express

Re: Control Tests for NH3-N
Reply #1 - Aug 20^th, 2012, 3:54pm

How accurate do you want these results to be? How low a number do you want to be able to report? What type of matrix are the samples? Most of the time, in order to get good ammonia numbers, you need to distill the samples prior to analysis. ISE usually can be accurate without the distillation step, but has its own idiosyncrasies to work out. The most important thing is to make sure the dissolved solids content is the same in samples and standards. Any sample color or turbidity will interfere with the colorimetric measurement. If all you need is something around a multiple of 10, see if you can find some test strips. They are crude in their numbers but will give you a general idea of what you are looking at.

Back to top

Working hard to bring reason to the field of regulation.

IP Logged

Dedalus

Full Member

Offline

Science is a
business of
empiricism.

Posts: 238
NY
Gender: male

Company or Organization: Dedalus Environmental

Re: Control Tests for NH3-N
Reply #2 - Aug 20^th, 2012, 4:41pm

I largely concur with David.

Depending how many samples you have, ISE is a pretty good method for your NH3 range. You might like to use the method of additions to get around matrix interferences. ISE methods lend themselves very nicely to the method of additions, as all you need do is shoot the spiking standard into the sample prep, and then just remeasure, rather than prep'ing multiple aliquots. I imagine you are treating buffered oxide etch, and are using lots of lime to neutralize it; hence you're adding lots of calcium.

A good thing to do is to immerse the probe in pH 4 buffer and stir it around for a couple of minutes between samples. This helps the probe come back to baseline.

As far as colorimetric methods are concerned, there's Nesslers (mercury hassles) and the manual phenate method (awkward to do)

And, if you want to go back to doing a bit of gaslight chemistry, you could always distill, and titrate.

Back to top

IP Logged

gregga

YaBB Newbies

Offline

Water and
Wastewater.com is
the best!

Posts: 24

Company or Organization: WSL

Re: Control Tests for NH3-N
Reply #3 - Aug 21^st, 2012, 9:03am

Hi, sorry but I am not sure if by "having trouble with these methods" means the samples are difficult to analyse or the operators are finding the methods cumbersome to use. If it is the latter you might like to think about high range vials, from Merck or other companies. With ours you just add 0.100 ml of sample with a pipette to a pre-dosed vial, add the colouring reagent by "clicking" out a shot of powder, mix, and wait 15 minutes. You then pop it in the spec and read off the concentration. I like this method because there is minimal prep and you can set the timer and do something else for 15 mins. But, if it is the sample with a complex matrix, then as mentioned I would think ISE (at those levels) would serve well.

I am also not sure what you mean about "control" samples, can you explain more please?

Greg.

Back to top

IP Logged

whearn11

YaBB Newbies

Offline

I love Water and
Wastewater.com

Posts: 10

Company or Organization: Micron Technology, Inc.

Re: Control Tests for NH3-N
Reply #4 - Aug 21^st, 2012, 12:48pm

Control samples are tests that the operators use to run the plant. Not for compliance. We don't treat for ammonia. If the ammonia is high, we will divert the flow to a retention basin and wait for the NH3 concentration to come down, then we will flow from the basin. In our stream that we sample/test, we have fluorides at 15 ppm, sulfate at 600 ppm, chloride at 200 ppm, COD at 100 (from Isopropyl alcohol) and sodium at 150 ppm. our in-house lab (not at treatment plant) analyzes our compliance samples with ISE Method 4500. We could get by with an accuracy of +- 5 ppm for ammonia. Could you be more specific about the high range vials?

Back to top

IP Logged

Dedalus Full Member Offline Science is a business of empiricism. Posts: 238 NY Gender: Company or Organization: Dedalus Environmental	Re: Control Tests for NH3-N Reply #5 - Aug 21^st, 2012, 1:34pm gregga wrote on Aug 21^st, 2012, 9:03am: With ours you just add 0.100 ml of sample with a pipette to a pre-dosed vial, add the colouring reagent by "clicking" out a shot of powder, mix, and wait 15 minutes. You then pop it in the spec and read off the concentration. That's interesting. What is the chemistry?
Back to top	IP Logged

joeb YaBB Newbies Offline I love Water and Wastewater.com Posts: 12 Mt. Pleasant, SC Gender: Company or Organization: Environmental Express	Re: Control Tests for NH3-N Reply #6 - Aug 22^nd, 2012, 7:17am Chemetrics makes some great test kits that are very easy to use as well. Here is a link to the ammonia test kit info on their website: http://www.chemetrics.com/Ammonia Joe
Back to top	IP Logged

gregga

YaBB Newbies

Offline

Water and
Wastewater.com is
the best!

Posts: 24

Company or Organization: WSL

Re: Control Tests for NH3-N
Reply #7 - Aug 23^rd, 2012, 7:04am

The Merck vials we use are based on EPA 350.1 (APHA 4500-D), the phenate method. It's well established, based on reaction of ammonia and hypochlorite in an alkaline solution to form monochloramine. This reacts with phenol to form a blue/green colour and read around 600 nm (the spectrophotometer automatically sets the wavelength once the method is selected). Several ranges are available, the higher the range the higher the tolerance to interference. There are cheaper ways to go, but they are pretty foolproof and setup is minimal. I dare say other brands have a similar setup.

Greg.

Back to top

IP Logged

IMRAN MURAD YaBB Newbies Offline I love Water and Wastewater.com Posts: 15 karachi Gender: Company or Organization: Combined Effluent Treatment Pl	Re: Control Tests for NH3-N Reply #8 - Aug 24^th, 2012, 2:26am NH3-N test is too easy on DR/2010 just purchase the vials from HACH company. Put the sample in it. After shaking and stay time green color will be developed, after all take the reading on spectro. Regards! IMRAN MURAD
Back to top	IP Logged