Hach-Lange NITRATAX sc - Manual (Page 24)

22
Operation
5.6.1 Adjusting turbidity compensation
1. Take a sample of activated sludge at the measuring location after the first half of the
aeration phase. Immediately after sampling approximately 100 mL, filter the sample
using a folded filter.
2. Similar to a standard solution, pour the filtrate into the measuring path of the sensor.
As an alternative, the measured value can also be determined by a laboratory
measurement (for NO
2
– N and NO
3
– N).
3. Select 1 SAMPLE CAL and measure the filtered sample.
4. Turn the wiper on and add sample until the measured value is stable.
5. Immerse the sensor in the activated sludge tank.
6. Start the wiper several times until a stable result is obtained for the activated sludge.
Add the difference mE
filtered
–mE
aeration
to the adjusted offset value.