Oil in Water measurement has traditionally been by means of grab samples taken to the laboratory. This is labor intensive as well as introducing systematic errors and time delay in getting the results. The OSPAR 40 mg/l discharge limit in place in the North Sea requires online Produced Water Analyzers to correlate with the defined reference method of GC-FID. To date, a number of technologies have been used to correlate an online analyzer method with the defined lab method.  Advanced Sensors Ltd’s results prove a consistent correlation over a rolling period of +/-1ppm.


UK based Advanced Sensors Ltd have developed a range of maintenance-free oil in water monitors that can be connected via the Internet. The OIW EX 1000 series of Oil-in-Water Analyzers offer a number of market firsts including;
    •  maintenance free self-cleaning
    •  remote connectivity
OIWEX1000     •  enhanced measuring range from ppb up to 20,000ppm
    •  online UV full scan spectrometer

The OIW EX analyzer uses patented ultrasonic self-cleaning technology. This removes the need for maintenance, and provides a consistent, reliable, measurement with ± 1% accuracy. The large robust measuring chamber removes the need for any flow control, mechanical mixers, chemical additives or human intervention.

Advanced Sensors Managing Director, Khalid Thabeth, said a major advancement in the EX1000 is that it is maintenance free.
“Oil in water monitors have historically been plagued with faulting and contamination of the measuring sensors, the OIW EX1000 incorporates an ultrasonic cleaning technique that ensures the sensors remain clean and measurement accuracy does not deteriorate,” said Thabeth.

OIW EX 1000 rear

When OIW-EX 1000 units are networked to the Internet or intranet, remote monitoring, control, and diagnostics are possible from anywhere in the world. The remote access to OIW-EX 1000 systems gives significant mobilization savings and ease of ownership.
Combined with 24 hour support from Advanced Sensors Ltd all clients benefit from a 100% success rate.  


“The unit is based on the Windows XP operating system and is supplied ready to connect to a companied network, this level of network connectivity allows the remote monitoring of the instrument and the remote diagnostics of the instrument by Advanced Sensors,” said Thabeth.


The OIW-EX 1000 has an extremely dynamic operating range, detecting oil concentrations from low PPB to 20,000PPM. Instruments can be placed at multiple points through the process and monitored from one location. Thus enabling proactive intervention and process optimization.

The OIW EX 1000 has an inbuilt optical spectrum analyzer that allows for enhanced analysis of produced water. The online spectrometer offers a new standard of analysis in produced water monitoring.

The OIW EX1000 is also able to detect other abnormalities in the water.“We can see if there’s an anomaly in what the unit is measuring by looking at the UV spectrum,” said Thabeth.“This allows the instrument to detect chemical additives present in the process.”


This market first offers information that was previously thought unattainable, empowering process engineers with a far greater insight of process dynamics resulting in even greater process management. Where detailed analysis of boiler feed water or heat exchanger mediums are necessary for process efficiency, the on line spectrometer can detect chemical anomalies in the sample stream.  Conversely, it is also possible to differentiate between normally present process chemicals and hydrocarbons in the produced water discharge. 

The operating system is built on the globally recognized Windows operating system, offering a familiar environment and making operation of the instrument self-intuitive. The flexibility of Windows XP gives the analyzer more software intelligence for calibration, diagnostics, detailed analysis and communications.

Data logging is fitted as standard in all OIW EX 100/1000 series analyses with a ten-year storage capacity. Software included helps users interrogate the detailed data, remotely or at the point of installation.


Managing Director Khalid Thabeth says:
“The revolutionary techniques employed in the product have enabled us to deliver a very exciting new product, with ground breaking features developed in close collaboration with our customers and partners. We are delighted with the result and believe we have set a new standard for oil in water monitors.”

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Technical Articles

Field Operational Experience with a New, Maintenance Free, Online Oil-in-Water Analyzer (.ppt) (Environmental and Water Quality Instruments) This presentation discusses the challenges of oil in water analysis. (View Full Article)
Overview of the Advanced sensors OIW units by Chevron. (Environmental and Water Quality Instruments) Background Older generation online oil-in-water (OiW) monitors may suffer from fouling of optics due to scales, soaps, emulsions, sludge, etc., resulting in inaccurate (usually low) concentrations. (View Full Article)