OptoDoSys_M – Optical DO

In-situ Fluorescent optical DO Detection

optical DO

Optical DO Sensor Technology

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 this innovative solid-state sensor is "Non consumptive", it does not require movement of the medium past the sensor.


optical DO installation

Example Installation - click to enlarge

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.

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 or 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).  You can network multiple units, including other instruments in the range (magflux and DO), for common display.

We regularly supply this sensor and transmitter combination to UK water companies and contractors. The system is flexible enough for contractors to easily 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.

 optical DO


optical DO installation

Air-Cleaned Sensor

Example Bespoke System

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


  • 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
  • Options for 230/115/24VAC and 10-30VDC power
  • Low cost of ownership
  • No frequent calibrations needed
  • Minimal maintenance
  • Accurate in low DO environments
  • Automatic error detection
  • No regular sensor refurbishment needed
Dissolved Oxygen

MJK DO Brochure

Click on the image to download the 2-page MJK DO brochure

Or contact us for more information on dissolved oxygen analysers

  • Format: PDF
  • Filesize: 972KB
Download Dissolved Oxygen brochure

Quote REQ


Click on the image to open a quote request form for the MJK DO system

Or contact us for more information on our range of analytical equipment

  • Activated Sludge monitoring & Control
  • Final Effluent Monitoring
  • Process Monitoring
  • River Monitoring Stations

case Studies


Click on the image to link to the Optical Dissolved Oxygen Case Studies page

Or contact us for more information on our range of analysers