OPUS - TriOS Mess- und Datentechnik

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OPUS

UV spectral sensor for the online measurement of nitrogens and carbons with a resolution of 0.8 nm/pixel.
Description Technical Data Measurement Ranges Application Examples Versions
OPUS is the new generation of spectral sensors for online measurement of nitrogen and carbon compounds. Through the analysis of a full spectrum, OPUS is able to deliver reliable readings for NO3-N, NO2-N, organic ingredients (CODeq, BODeq, DOCeq, TOCeq), and a number of other parameters.
OPUS features the new TriOS G2 interface, allowing fast and easy configuration of sensors by using a web browser. Integration into existing process control systems and external data loggers has never been easier.
With the optional battery pack, mobile applications are also feasible. WiFi connectivity allows laptops, tablets or smartphones to be easily used for control without any special application software or app installation.
Light source
Xenon flash lamp
Detector
High-end miniature spectrometer
256 Channels
200 to 360 nm
0.8 nm/pixel
Measurement principle
Attenuation, spectral analysis
Optical path
0,3 mm, 1 mm, 2 mm, 5 mm, 10 mm, 20 mm, 50 mm

Parameter
Nitrate NO3-N, Nitrite NO2-N, CODeq, BODeq, DOCeq, TOCeq,
TSSeq, KHP, SAC254, COD-SACeq, BOD-SACeq
Measurement accuracy
see measurement ranges next page
Turbidity compensation
Yes
Data logger
~ 2 GB
T100 response time
2 min
Measurement interval
≥ 1 min

Housing material
Stainless steel (1.4571/1.4404) or titanium (3.7035)
Dimensions (L x Ø)
470 mm x 48 mm (bei 10 mm path)
~ 18.5“ x 1.9“ (with 10 mm path)
Weight stainless steel
~ 3 kg (bei 10 mm path)
~ 6.6 lbs (with 10 mm path)
Weight titanium
~ 2 kg (bei 10 mm path)
~ 4.4 lbs (with 10 mm path)

Interface digital
Ethernet (TCP/IP), RS-232 or RS-485 (Modbus RTU)
Power consumption
≤ 8 W
Power supply
12...24 VDC (± 10 %)


Maintenance effort
≤ 0.5 h/month (typical)
Calibration/maintenance interval
24 months
System compatibility
Modbus RTU
Warranty
1 year (EU: 2 years)
US: 2 years

Max. pressure with SubConn
30 bar
~ 435 psig
Max. pressure with fixed cable
3 bar
~ 43.5 psig
Max. pressure in FlowCell
1 bar, 2...4 L/min
~ 14.5 psig at 0.5 to 1.0 gpm
Protection type
IP68
NEMA 6P

Sample temperature
+2...+40 °C
~ +36 °F to +104 °F
Ambient temperature
+2...+40 °C
~ +36 °F to +104 °F
Storage temperature
-20...+80 °C
~ -4 °F to +176 °F
Inflow velocity
0,1...10 m/s
~ 0.33 fps to 33 fps
Parameter
Measurement principle
Unit
Factor
path length [mm]




0.3
1
2
5
10
20
50
absorbance
spectral
AU**
-
0.01...2.2
0.01...2.2
0.01...2.2
0.01...2.2
0.01...2.2
0.01...2.2
0.01...2.2
absorbance
spectral
1/m
-
50...7300
15...2200
7.5...1100
3...440
1.5...220
0.75...110
0.3...44
Nitrate N-NO3
spectral
mg/L
-
1.0...330
0.3...100
0.15...50
0.06...20
0.03...10
0.015...5
0,006...2
Nitrate NO3
spectral
mg/L
-
4.43...1460
1.33...440
0.67...220
0.27...88
0.13...44
0.067...22
0.030...9
Nitrite N-NO2
spectral
mg/L
-
1.7...500
0.5...150
0.25...75
0.1...30
0.05...15
0.025...7.5
0.01...3
Nitrite NO2
spectral
mg/L
-
5.6...1650
1.65...500
0.82...250
0.33...100
0.17...50
0.083...25
0.033...10
DOCeq
spectral
mg/L
-
17...3300
5.0...1000
2.5...500
1.0...200
0.5...100
0.25...50
0.1...20
TOCeq
spectral
mg/L
-
17...3300
5.0...1000
2.5...500
1.0...200
0.5...100
0.25...50
0.1...20
CODeq
spectral
mg/L
-
100...7300***
30...2200***
15...1100***
6.0...440***
3.0...220***
1.5...110***
0.6...44***
BODeq
spectral
mg/L
-
100...7300***
30...2200***
15...1100***
6.0...440***
3.0...220***
1.5...110***
0.6...44***
KHP
spectral
mg/L
-
17...13300
5.0...4000
2.5...2000
1.0...800
0.5...400
0.25...200
0.1...80
SAC254
Single wavelength
1/m
-
50...7300
15...2200
7.5...1100
3.0...440
1.5...220
0.75...110
0.3...44
COD-SACeq****
Single wavelength
mg/L
1.46
75...10600
22...3200
11...1600
4.4...640
2.2...320
1.1...160
0.44...64
BOD-SACeq*****
Single wavelength
mg/L
0.48
24...3500
7.2...1050
3.6...525
1.44...210
0.72...105
0.36...52.5
0.15...21

TSSeq*****
Single wavelength
mg/L
2.6
130...4300
40...1300
20...650
8.0...260
4...130
2.0...65
0.8...26




under laboratory conditions
** absorbance unit
*** depending on the composition of the COD and BOD (sum parameter)
**** based on KHP (Note: 100 mg/L COD-standard-solution corresponds to 85 mg/L KHP)
***** based on SiO2

Note:
1 mg/L N-NO3 corresponds to 4.43 mg/L NO3
1 mg/L N-NO2 corresponds to 3.28 mg/L NO2






Nitrate / nitrite measurement in the biological effluent of a wastewater treatment plant
The already existing filtration oft he wastewater treatment plant for the ammonium analyser was used and the OPUS UV probe was installed in the bypass by means of a flow cell. The optical measurement in the clear medium allowed the path length of the sensor to be increased from 1 to 2 mm, thus achieving more accurate measurement results.

 
Furthermore, averaging was not necessary, since the individual measurements were stable after filtration. The set measuring interval was 2 min. The dynamics of the fast processes were thus reflected without damping.

 
The OPUS UV probe was equipped with a nitrate/nitrite calibration, so that the nitrogen balance of the measuring point could be recorded correctly.

 
The results showed that a spectral probe must necessarily be used at this measuring point, which can detect nitrate and nitrite in a differentiated manner. Besides nitrate, nitrite is always present in non-negligible concentrations, which interferes with an NOx measurement and produces deviating measurement results.

 
The optical properties of nitrate and nitrite are similar. They absorb UV light of almost the same energy or wavelength. If the UV measurement is carried out at only one wavelength, as is the case with optical NOx sensors, it is not possible to differentiate between these two parameters. The result is output as a pure nitrate value and differs significantly from the real concentrations in the presence of nitrite. Only with a spectral evaluation over a larger wavelength range with sufficient resolution, as is the case with the OPUS UV probe, can these two parameters be determined simultaneously and accurately.

 The installation of the probe in the bypass is of great advantage at this point. In a clear medium, measured values can in principle be determined more stably and precisely. Damping is also not necessary. Fast processes can be reproduced realistically.

You can read the detailed report including all test results here:
Further application descriptions will follow.

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