OptoDoSys_M – Optical DO

In-situ Fluorescent optical DO Detection

optical DO

OptoDOSys_M is an Optical DO sensing system from MJK & Insite lG, ideal for use in wastewater treatment works. The technology is based on the quenching of Ruthenium salt fluorescence by the presence of Dissolved Oxygen. Because it is "Non consumptive", it does not require movement of the medium past the sensor.

It is also very accurate at low DO levels and because of this feature, is useful in anoxic and anaerobic sections. The sensor design together with optional air/liquid cleaning reduces maintenance to a very low level, and the 5 yr sensor warranty guarantees your low cost of ownership.

optical DO installation

Example Installation - click to enlarge

Because this system uses the Insite IG optical DO sensor, you won't have to change end caps, membranes or consumables. The sensor is not affected by ambient light and is not harmed by drying out because of the solid state technology.

The transmitter

You can link the optical DO sensor to a MJK transmitter/display making great use of this versatile unit. The transmitter includes data logging for up to 30000 time stamped readings and has a real time graphic display. You may download data to a computer via a USB using the free MJK software.
Other outputs include 4-20 mA analogue signal, 2 relays and modbus for direct Scada link (profibus converter available on request). There is one digital input that you could use to activate the cleaning cycle. You can network multiple units, including other instruments in the range (magflux and DO), for common display. The sensor has no end caps or replaceable chemicals and is not affected by drying out or ambient light.

We regularly supply this sensor and transmitter combination to UK water companies and contractors. The system is flexible enough for contractors to integrate it into their own installation plans. We also provide a bespoke option where we can supply you with a complete system including a cleaning compressor in a housing for quick installation on site.

This transmitter is also available in a range of power options including 10-30VDC, 24VAC, 115VAC and 230VAC. Our cleaning compressor usually requires 115VAC power, however we do have options for 24VDC cleaning too.


- Optical DO sensor technology
- Advanced microprocessor design
- Automatic optional Air cleaning
- No replacement parts required
- 5 yr warranty on sensors
- Backlit LCD display
- Analogue and digital, modbus outputs + optional profibus
- Real time graphics & logging


- Low cost of ownership
- No frequent calibrations needed
- Minimal maintenance
- Accurate in low DO environments
- Automatic error detection
- No regular sensor refurbishment needed


optical DO

Example System

  • Optical DO transmitter
  • Cleaning option
  • Weatherproof housing
  • Push button cleaning
  • Click on picture for more detail

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- Activated sludge monitoring & control
- Final effluent monitoring
- Process monitoring
- River monitoring stations
Air cleaned area
cleaned optical DO sensor

Optical DO brochure Download a brochure optical DO quote Quote for OptoDoSys M