IMO issues guidelines for managing anti-fouling waste

Eda Zenic -

The International Maritime Organization has issued comprehensive guidelines (AFS.3/Circ.6) for the handling and disposal of waste generated during anti-fouling systems (AFS) maintenance and cleaning. These guidelines aim to mitigate the environmental impact of anti-fouling practices, especially regarding the contamination of marine environments, and to ensure that waste is handled responsibly throughout the process.

According to the IMO's guidelines, different types of AFS waste must be collected and stored separately in containers specifically designated for each waste type. Once the work is completed, these waste containers should be removed and transported to specialized facilities for further treatment. The guidelines clearly state that waste should not be disposed of by washing it with water, brushing it into the environment, or burying it. Likewise, incineration or permanent storage of such waste at the facility is strictly prohibited to avoid further environmental contamination.

Wastewater contaminated with hull coating materials is another significant concern. The IMO recommends that such wastewater be stored separately from other liquids in closed containers until it can be properly treated. Before treatment, the wastewater should be left standing to allow suspended particles to settle, thus separating the contaminated particles from the water. Once treated, the wastewater should comply with predefined environmental standards, such as a specific Total Suspended Solids (TSS) content and a pH range (e.g., between 6.5 and 9 pH units). The treated water may be disposed of through the sanitary sewer system if it meets national chemical standards, but local authorities must be notified in advance. Furthermore, discharges into sensitive marine areas should be avoided to prevent the introduction of invasive species or other contaminants from the wastewater.

Particulate waste, such as grit and paint chips, generated during dry operations like scraping, grinding, sanding, or grit blasting, must be collected and removed immediately after the work is completed. If the work lasts several days, the waste should be removed daily to prevent accumulation. Grit may be reused if it is not contaminated, but if it is unsuitable for reuse or recycling, it should be transported to a licensed facility for safe disposal or treatment. In the absence of a licensing system for waste disposal, the contaminated grit and sediment must be directed to a landfill lined with an impermeable liner to prevent contamination of groundwater or surface water.

For wet grit blasting operations, wastewater must be contained and the remaining grit collected. Contaminated grit should either be cleaned and reused or safely disposed of at a licensed facility. Again, if a licensed disposal facility is unavailable, the grit should be directed to a landfill that is properly protected from leaching. It is also crucial that contaminated sediment separated from wastewater be treated and transported to a licensed facility for safe disposal.