The NH3-N ​​reduction rate of stripped sour water is low, if we consider the TKN of  stripped sour water, the NH3-N of effluent is higher than influent.

Why does the NH3-N of stripped sour water not react to NO3-N? Is the cresol of stripped sour water to inhibit the microorganism, or the nutrient content of  stripped sour water too poor to active the AOB/NOB, or others we still not know.

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8 Answers

1. we try to use the L tank sludge ,which is good for NH3-N ​​​reduction , and the mixed sludge(50% L sludge and 50% original M tank sludge ) is enhance the NH3-N ​​​reduction of the stripped sour water in the Lab. But in the plant , it is not easy to transport the sludge about 4000 M3 (MLSS) from L tank to M tank. we transport the L tank slugde about 1% per day to M tank , lasts about 2 month , but that cannot work. we think maybe some composition of water, such as cresol, affect the performance of L tank sludge, the 1% per day lasts 2 month cannot equivalent the 50% of L tank sludge.

2. What is the Alkalinity in the MBR? Nitrification removes alkalinity and even with denitrification only 2/3 is recovered.

   "During nitrification , 7.14 mg of alkalinity as CaCO3 is destroyed for every milligram of ammonium ions oxidized. ... After complete nitrification , a residual alkalinity of 70 to 80 mg/L as CaCO3 in the aeration tank is desirable. If this alkalinity is not present, then alkalinity should be added to the aeration tank" - CWEA-WEF June,25 2015

   Abstract

   p -Cresol at 17 mg l−1 in a nitrifying culture inhibited by 70% nitrate formation whereas at 10 mg l−1 there was no effect. p -Cresol at 220, 470, and 910 mg l−1 was converted to intermediates after adaptation times of 8 h, 24 h, and 40 h, respectively. The sludge recovered 44% of its activity after transformation of p -cresol.

   Tolerance of nitrifying sludge to p -cresol

   • A.-C. Texier &
   • J. Gomez 

   Biotechnology Letters volume 24 , pages321–324(2002)Cite this article

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   • 12 Citations

   1 Comment

   1. ​the alkalinity by NIEA W449.00B (2003) is about 70 ppm (50~123 ppm)

3. Thank you for the parameters. I would increase MLSS. DO is good, so I think you just need more bugs to get the treatment you want. That said, there are things that can inhibit nitrification but I don't know them all off the top of my head. I would check nutrient levels and metals.

   I run a plant that removes ammonia, warm weather MLSS can be as low as 2500, cold weather we increase to 4200. To combat M.Parvicella in the winter we also dose with PAX 14 from Kemira in winter.

   1 Comment

   1. 1.the stripped sour water COD is about 500~800 ppm, the  quantity is about  3,500 M3/D, the MLSS is about 2,500~3,500 ppm, I think the sludge system is all right.
      2.the conductivity of  stripped sour water is about 50 uS/cm, I think the water has little ions.
      3.the phosphoric is added about 7 ppm, the N should be sufficient.
      4.now we try to add other wastewater(domestic wastewater) to increase the nutrient and test in Lab preparatory.

4. May I understand sour water as acidic, than it's clear that stripping doesn't work, as Ammonia is as NH4+ Ion existing. Stripping of Ammonia is successful pH > 10.5.

   1 Comment

   1. 1.the pH of stripped sour water is about 6.5~7.5.

      2.the NH3-N  and org-N total of stripped sour water  is about 30 ppm(TKN), and we think that could be deal by activated ​sludge system. ​

5. Is oxygen level in the reactor  sufficient for nitrification.  If BOD reduction is taking place and nitrification is not happening to desired level, then check Dissolved Oxygen level in the reactor. 

   1 Comment

   1. the DO should be sufficient, the DO of  tank combines moving bed ​biofilm and ​activated ​sludge system ​is about 4 ppm.

6. I also would have expected the Ammonia to become nitrates unless you may have some other organic compounds (maybe Amines) that are not reacting within your biological treatment process. You need to figure it out inside your TKN values...

   1 Comment

   1. the average TKN of ​influent is about 33 ppm,the average TKN of effluent is about 30 ppm, the reduction rate of TKN is very weak.

7. What is the mixed liquor recirculation flow?

   1 Comment

   1. 1.the recirculation flow of the mixed liquor is about 3.5Q, to meet the MLSS 2,500~3,500 ppm, the moving bed biofilm and activated sludge system combinesed.

      
      2.the stripped sour water is treated by sludge, filter by MBR system , and supply to cooling tower as part of make-up water.

8. A description of your process, parameters and industry would help.

   1 Comment

   1. 1.the ​stripped sour ​water is ​treated by ​DAF,sludge(combines moving bed ​biofilm and ​activated ​sludge ), filter ​by MBR system, and supply to ​cooling tower ​as part of make-​up water. ​
      2.the ​recirculation ​flow of the ​mixed liquor is ​about 3.5Q, to ​meet the MLSS 2,​500~3,500 ppm.the DO is 3~4 ppm; pH 6.5~7.5.
      3.the ​influent ​COD 500~800 ppm, NH3-N 2~40 ppm,TKN 15~80 ppm, NO2-N and NO3-N ~0 ppm.
      4.the effluent COD 15~40 ppm, NH3-N 10~50 ppm,TKN 15~50 ppm, NO2-N and NO3-N ~0 ppm.