Closed-Loop Scrubbers: Advanced Solutions for Marine Emission Control

As international regulations on ship emissions continue to tighten, reducing sulfur oxides (SOx) and other pollutants from vessel exhaust has become a critical focus for the maritime industry. Among available technologies, Closed-Loop Scrubbers have emerged as an effective solution for controlling air emissions while minimizing environmental impact on marine ecosystems.

A closed-loop scrubber operates by recirculating a specially treated washwater within the system. Exhaust gas from the engine passes through the scrubber, where acidic pollutants such as SOx are absorbed by the recirculating alkaline water. The washwater is continuously treated and monitored onboard, and only a small, controlled volume is discharged after meeting environmental standards. Compared to traditional open-loop systems, this approach significantly reduces the direct release of pollutants into the surrounding sea, offering better control over both air emissions and wastewater management.

Scientific Evidence and Environmental Considerations

Recent peer-reviewed studies highlight the importance of proper washwater management. A 2023 study published in Frontiers in Marine Science reported that scrubber washwater, even from closed-loop systems, can affect marine organisms, altering reproduction, growth, and community structures of zooplankton populations. Similarly, a 2025 review in Integrated Environmental Assessment and Management concluded that scrubber effluent can exhibit toxicity at environmentally relevant concentrations, emphasizing that air emission reduction alone does not fully mitigate environmental risks. These findings underscore the necessity of integrating both air and water treatment measures in marine exhaust systems.

Comprehensive Solutions for Shipowners and Operators

To address these challenges, we provide complete marine exhaust gas treatment solutions. Our offerings include:

  • Design, installation, and commissioning of closed-loop scrubber systems
  • Integrated onboard washwater treatment and recycling solutions
  • Customized configurations for new vessels and retrofit projects
  • Technical support to ensure regulatory compliance and long-term operational reliability

By combining advanced closed-loop scrubber technology with effective washwater management, shipowners can achieve regulatory compliance, protect marine environments, and maintain efficient vessel operation.

For ship operators and fleet managers seeking a reliable and environmentally responsible approach to exhaust gas management, our solutions offer a practical and compliant path forward.