The SMART ESM is a washwater monitor for wet scrubber systems measuring and recording PAH, Turbidity, Temperature and pH.


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With the IMO’s 2020 global sulphur cap fast approaching, a popular solution to ensure compliance is to install an exhaust gas cleaning system (EGCS).

For this, wet scrubber systems use wash water to remove the pollutants from the exhaust gas. Therefore the wash water being discharged must be monitored at all times to ensure it is within the limits set by the regulating body. There are IMO regulations for water quality parameters including Polycyclic Aromatic Hydrocarbons (PAHs), pH and turbidity prior to discharge into the ocean.

Rivertrace is an ISO 9001 Quality-Assured Company and market leader in Oil in Water Quality Monitoring, with over 30 years’ experience and your partner to ensure that the wash water discharged from your exhaust gas cleaning systems is compliant with the global regulations on discharge.

Our SMART ESM monitor developed by Rivertrace, is suitable for both the inlet and outlet of a wet exhaust gas cleaning system, measuring and recording PAH, Turbidity, Temperature and pH, on open-loop, closed-loop and hybrid scrubber systems.

The SMART ESM is fully compliant with MEPC 259(68) and provides reliable information to ensure compliance with the worldwide SOx limits.

  • PAH Measurement is compensated for turbidity
  • Continuous real-time monitoring of wash water discharge including PAH, turbidity, Temperature and pH
  • Automatic cleaning of optical path
  • Unique Plug and play maintenance design – Separate calibrated PaH and Turbidity cassettes fitted inside the measuring cell allow the calibrated parts to be swapped without the need of isolating the sample
  • Simple calibration check kits for accuracy verification
  • On screen historical data graphs and a broad selection of inbuilt analogue and digital outputs.
  • Flexible solutions to suit requirements
  • Customisable measurement parameters as per customers requirement.
  • Complete sample conditioning unit provided
  • Ensures compliance of wash water discharge from ship EGCS is within regulatory limits
  • Fully compliant with IMO MEPC 259(68)
  • Systems suitable for both new ship and retro fit installations
  • Compatible with Open Loop, Closed Loop and Hybrid systems
  • Suitable for inlet and outlet monitoring

At Rivertrace we understand every EGCS is different, and we can tailor our system to accommodate the specific parameters and requirements for the scrubber and vessel.
We offer 2 main designs for our equipment which can be customised further with additional components based on technical requests.

Option 1 – Frame Mounted. This option is based on a modular design all mounted onto a frame / backplate. It consists of a cooled cabinet housing the Control Module and Measuring Cell with a separate enclosure for the electronics.

Option 2 – Box Mounted. This option is based on a twin enclosure design.
It consists of a cooled cabinet housing the Control Module and electronics and a separate compartment for the Measuring Cell and sample conditioning equipment.

Other optional components include:

  • Sample Heat Exchanger should be included is the sample temperature is above 40degC
  • Motor / Pump should be included if the pressure in the sample line is below 0.5bar

SMART ESM – Frame Mounted (FM) Configuration with Sample Heat Exchanger and Motor Pump

SMART ESM – Box Mounted (BM) Configuration with Sample Heat Exchanger and Motor Pump


PAH Range 0μg/L to 4500μg/L
PAH Accuracy 5% of measurement reading
PaH Measurement Principle UV Fluorescence
Turbidity Range 0 – 500 NTU
Turbidity Accuracy 0.1NTU up to 100 NTU, 1NTU thereafter.
Turbidity Measurement Principle IR Scattering
pH Range 0 – 14 pH
pH Accuracy 0.1 pH
pH Measurement Principle pH Electrode
Sample / Clean Water Temperature range 0oC to 40oC*

*Higher optional with Heat Exchanger

Sample / Clean Water pressure range 1 to 9 Bar
Optimum Measuring pressure (Sample / Clean) 3 Bar
Required Air Supply Pressure Range 4 – 6 Bar
Compressed Air normal / average consumption 450mL / Hr
Sample / Clean Water Flow rate range 1 to 4 LPM
Ambient Temperature range 0°C to 50°C
Supply Voltage 230 VAC 50/60 Hz
Outputs MODBUS


Response Time 266 seconds at 1l/m flow rate
Storage Internal SD Card

Downloadable to External USB

IP Rating IP66
Wetted Parts Material uPVC, Nylon, Black acetal copolymer and peek
Approvals DNV Certificate of Conformity