The importance of monitoring wash water for scrubbers cannot be understated. It is clearly crucial for shipowners that they take the best option for their vessels and operations to ensure compliance with the regulations. For those considering making the investment in scrubbers, they will need to fully understand both the regulatory and operational implications and will actively seek reassurance that making the investment to install a system will result in compliance with all applicable regulations. For scrubber manufacturers, the onus is on them to provide reliable proof that their systems are fit for purpose and will not create further regulatory complications for their customers. It is only though accurate monitoring that both of these criteria can be met.

Importance of Monitoring Wash Water

Wet scrubbers use wash water to “clean” emissions before they are released into the atmosphere. It is this water that must be accurately monitored at all times to avoid discharges that may exceed regulations and damage the environment. Chelsea Technologies has direct experience of compliance testing and has an in-depth working knowledge of the high standards demanded by regulators. Chelsea’s Sea Sentry scrubber wash water monitoring system has the capability to accurately measure the required parameters of water in closed loop scrubbers, providing accurate data that proves compliance with wash water regulations.

Chelsea’s Sea Sentry provides a fully autonomous wash water monitoring system which monitors both the water inlet and outlet of wet exhaust gas scrubber systems. The system analyses wash water to ensure that it is compliant with environmental regulations which reduce potentially high levels of contamination in exhaust gas scrubber wash water discharge.

Closed loop scrubber systems present a unique challenge when monitoring water as the recirculation process darkens the water, making it difficult to obtain an accurate PAH measurement. It is by adapting the monitoring process to not only measure the turbidity and absorbance levels, but to apply these values as a correction to the PAH measurements, that accurate readings can be taken. If the readings are not accurate, owners are risking significant fines or detention.

It is essential that crews have a thorough understanding of the regulations, monitoring procedures and the analysis and interpretation of the data. Chelsea technologies works closely with shipowners, leading global scrubber manufacturers, and the Exhaust Gas Cleaning System Association, to provide engineers with the knowledge and expertise they need to operate with the highest level of confidence in their system and in proving compliance under the IMO criteria. Sea Sentry is DNV Type Approved, DNV-GL and Class NK in compliance with IMO MEPC 259(68) and new regulations from January 2023 MEPC 340(77), and measures the PAH, absorbance, turbidity (to ISO 7027: 1999), temperature and pH of scrubber washwater.

The route to compliance is complicated and there is no “one size fits all” option. Shipowners and operators must weigh up the costs and benefits associated with each option although there is increasing evidence that scrubbers have an important role to play.  But with increasing environmental regulation, accurate monitoring will be essential to provide operators with confidence in their investment, as well as in the reliability and accuracy of their systems to remain compliant and enjoy continued access to markets.

Monitoring Wash Water with Sea Sentry

Given their high cost, the way to ensure confidence in the future return of a scrubber installation is to use an accurate, maximum range wash water monitoring solution as an integrated part of the scrubber system design. Ensuring scrubber compliance requires a monitoring system that can be trusted and operated easily by crew. Chelsea Technologies’ Sea Sentry is designed with this in mind; the highly adaptable system embeds unique technologies to ensure its adaptability, reliability, and ease of management at sea. The monitoring system contains self-maintaining features, including an integrated air purge antifouling system, automatic monitoring of the optical sensor window, automatic PAH measurement adjustments for turbidity, UV absorbance and temperature, and an integrated pump, de-bubbler, pressure relief system and flow metering.

MEPC 340 (77) Compliant Sea Sentry: Features & Applications

• Fully integrated turnkey solution for monitoring wash water and meet IMO regulations
• DNV Type Approved, DNV-GL and Class NK in compliance with IMO MEPC 259(68) and new regulations from January 2023 MEPC 340(77)
• Suitable for retro fit and new installation of open, closed loop and hybrid scrubber system
• Full PAH Range – Full 0 – 4,500µg/L PAHphe measurement which provides full compatibility with all scrubber system flow rates
• Two year calibration intervals on the PAH+ and Turbidity sensors allowing for uninterrupted monitoring
• Easy to use onboard sensor check – the new Chelsea solid standards kit allows you to verify the sensor calibration onsite with easy to operate, robust and stable solid standards as part of the commissioning process, without the need for liquids or chemicals
• Chelsea designed sensors and cabinet– as designers and manufacturers of both the sensors and complete system, Chelsea knows the science and the technology
• Confirms wash water from ship exhaust gas cleaning systems is within regulatory limits
• Suitable for both new ship and retrofit installations
• Compatible with Open Loop, Closed Loop and Hybrid systems