Hi Lin, You are right, the ...

Hi Lin,

The reactor temperature is much higher than my typical experience, but this should have a positive impact on nitrification. Because we don't know what the sludge age is, I would recommend that the MLSS is maintained at higher levels (and higher sludge age) rather than lower levels as a safety precaution for nitrification. From the info available I would say that the current problem was due to a reduction in alkalinity (due to nitrification or feed) coupled with an increase in ammonia concentration. Nitrification will utilise alkalinity resulting in pH instability and lower pH values. Lower pH values will result in lower nitrification rates (pH below 7.0 will significantly reduce nitrification rates as the pH reduces). I would therefore recommend that alkalinity/pH is adjusted upward by lime (or other base) dosing. pH adjustment should be accurately controlled as a high pH will also impact negatively on nitrification.

If alkalinity/pH is not the problem, it could be some nitrification inhibitory substance in the feed or which became more prominent due to the change in load.

Regards

Published September 15, 2020 10:12 by Andre Visser, Process Engineer at Water Engineering Consult

Permalink

Q1. How ​long has the ​load been lower ​or at what date ​did the load ​decrease,
A1. The load lower initiate date is 8/22, and the NH3-N ​reduction rate ​decreased ​is 8/28.

Q2. ​What is the ​reactor water ​temperature,
A2. ​The temperature ​is about 35℃.​

Q3. ​what sludge ​age are you ​operating the ​reactor
A3.The sludge ​we drain is 5 ​mins every 30 ​mins, the ​sludge age we do not calculae yet.

Q4. ​what procedure ​do you follow ​to control the ​sludge age/MLSS ​concentration? ​
A4.To maintain the MLSS is about 3,000~3,500 ppm.

Published September 14, 2020 03:32 by Lin JYH-YAN, advanced engineer at FORMOSA PETROCHEMICAL CORPORATION

Permalink