Intended Use; Theory Of Operation; Product Overview - Hach NT3100sc Manuel D'utilisation

2.2 Icons used in illustrations
Manufacturer supplied
parts

2.3 Intended use

The NT3100sc and NT3200sc probes are intended for use by water treatment professionals to make
sure that there is a consistently-low level of nitrate and nitrite in the municipal sewage at treatment
plants, surface water, untreated water and treated drinking water. Low nitrate and nitrite levels
prevent water toxicity exposure and/or make sure of regulatory compliance.

2.4 Theory of operation

Nitrate dissolved in water absorbs UV light with wavelengths below 250 nm. The nitrate and nitrite
absorption of UV light makes it possible to photometrically determine the dissolved nitrate and nitrite
concentrations without reagents. The sensor is put directly in the medium. The color of the medium
does not have an effect on the measurement because the measuring principle is based on the
analysis of invisible UV light.

2.5 Product overview

Use the NT3100sc probe to measure nitrate concentrations and the NT3200sc probe to measure
nitrate and nitrite concentrations. Refer to
Use the probe in activated sludge tanks in municipal sewage treatment plants, surface water,
untreated water and treated drinking water, or the outlet of wastewater treatment plants. Pumping
and conditioning are not necessary. Put the probe directly into the medium.
Note: Use the flow through unit when direct measurement in the medium is not possible or it is necessary to
measure a filtered sample (e.g., very high TSS
Connect the probe to an SC Controller for power, operation, data collection, data transmission and
diagnostics. Refer to the SC Controller manual for an overview of the controller.
The probe has a beam absorption photometer with turbidity compensation. A built-in wiper
mechanically cleans the measuring window.
Note: Enable the sludge mode to increase the number of concentration measurements done when the probe
measures in activated sludge. When sludge mode is active, several measurements are done to compensate for the
different sludge compositions.
Dissolved nitrate and nitrite, dissolved organics and particles absorb light, which has an effect on the
measurement absorbance value. The probe adjusts for this turbidity interference. However, there
may be applications where the combination of these compounds absorbs too much light. Thus, there
is not sufficient light transmitted to the sensors and inaccurate measurements occur. Make sure to
select the probe with the correct pathlength. Refer to
Table 1 Recommended pathlength—NT3100sc nitrate probe
Application
Wastewater
Influent
Nitrification/denitrification
Nitrification/denitrification, more than 5,000 mg TSS/L sludge
3
The TSS value is a recommendation and based on the substances of the wastewater.
Mandatory action Do not use tools
Figure
3
content, sewage treatment plant inlet or waste dump leachate).
Do steps in reverse
order
1.
Table 1 and Table
Do one of these
options
2.
Pathlength
1 mm 2 mm
✔ ✔
✔ ✔
✔
English 7
5 mm