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Jerome Le Cunff YaBB Newbies Offline I love Water and Wastewater.com Posts: 15 Gender: Company or Organization: Freelance	High NO2- in effluent May 16^th, 2012, 3:45am Hi, I run a wasteland leachate wastewater facility, we use a SBR facility and recently strange analysis results came in. The COD removal droped and I have a great increase in NO2- concentration in the effluent. It's 0,6 mg/l coming in and 1,5 mg/l in the effluent. The values for the effluent ere around 0,4 mg/l so far. Thank you
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Jerome Le Cunff YaBB Newbies Offline I love Water and Wastewater.com Posts: 15 Gender: Company or Organization: Freelance	Re: High NO2- in effluent Reply #1 - May 16^th, 2012, 3:51am And another thing, seems the COD in the effluent is high because there are a lot of fine suspended particles that don't setle well, I'll have to add FeCl3 for that, what would be the best time? Continous or at a specific phase of the process?
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The sludge judge

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Re: High NO2- in effluent
Reply #2 - May 16^th, 2012, 8:50am

Increase in nitrite is usually associated with low DO or some inhibition/ toxicity. Treating leachate, I think you probably got hit with a small amount of something the plant didn't handle well.

A micro exam is a good thing here. I suggest running some fed OURs on your influent to determine if there's something inhibitory going on. If not, a slight decrease in wasting and making sure there's enough DO and good pH/ alkalinity for full nitrification should help things come around.

You can filter your effluent and run a soluble COD to determine how much of this COD in the effluent is from the TSS and how much is "food" going through the plant.

best regards,

Ryan

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grrun God Member Offline WaterandWastewa ter.Com is the best! Posts: 3525 Pekin, IL Gender: Company or Organization: Freelance Environmental Engine	Re: High NO2- in effluent Reply #3 - May 16^th, 2012, 11:54am In addition to Sludgefather's comments; sludge age could affect the results because of the lack of full nitrification. Before committing to adding FeCl₃, I would check operating conditions. The daily WAS should be <10% for good nitrification. This would probably help COD removal as well. Do you have an anoxic cycle? grrun
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DrHenry God Member Offline Ride, boldly ride, The shade replied... Posts: 788 Raleigh, NC Company or Organization: CESTAB (see bio)	Re: High NO2- in effluent Reply #4 - May 16^th, 2012, 5:41pm Just to add another line of thought. It would not hurt to split a sample with another lab to make sure the higher numbers are real.
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Tom Keenan - nesa God Member Offline Environmental Consultant - contact info@nesa.ie Posts: 2103 Gender: Company or Organization: nesa environmental consultants	Re: High NO2- in effluent Reply #5 - May 17^th, 2012, 4:29am In support of the DrHenry theory.... if you have very fine suspended solids, or colour, in the effluent maybe either or both could be interfering with the test procedures, or colorimetric readings.
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Jerome Le Cunff

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Re: High NO2- in effluent
Reply #6 - May 21^st, 2012, 4:32am

You are right, but because of the coloration I did dilute the sample to try and get more accurate readings and the results stay the same. I do have an anoxinc cycle but am still waiting for better stiring equipement. I will however send samples to external labs and see what happens. I did another experiment, I took an effluent sample and added 1ml od 40% mas. of FeCl3 solution and got 250 ml of flocs, in some semi suspended state. This means I have way to much suspended solids in the effluent.

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cjcj1975 Senior Member Offline Water and Wastewater.com is the best! Posts: 312 Company or Organization: BDC	Re: High NO2- in effluent Reply #7 - May 21^st, 2012, 6:49am High nitrite is also relates with low temperature. How much is influent temperature?
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