Ballast Water Treatment at Muddy Water Ports


India has been advocating for port-based mobile treated ballast water delivering facilities called BWTBoats since 2013. Given the recent real-world experiences with the challenges of ballast water treatment at muddy water ports and the forthcoming financial burden for ship owners to comply with the 2020 sulfur cap, a port-based treatment model – BWTBoats – could be a viable solution to avoid the cost of retrofitting ballast treatment systems aboard ships. 

Twist in BWM convention implementation

At recent MEPC & PPR sessions, IMO discussed the issue of contingency measures in the event that a ship’s ballast water is non-complaint after use of onboard treatment systems. In response to this, South Korea submitted a paper (MEPC 71/4/21) which is eye opening for industry. They claim that systems are not working properly  in ports with challenging water quality (PCWQ) i.e. muddy water ports. According to the report, during ballast uptake of muddy water, systems are clogging or ballasting operations are delayed beyond unexpected limits due to frequent start/stop back-flushing.

For this circumstance, the Korean authors suggested an onboard contingency measure in which it is advised that in PCWQ, treatment systems should not be used and untreated water ballast be taken on board as it is. The ship would then exchange this water on the high seas or mid-ocean with water treated by the ship’s BWMS.

Canada (PPR 5/23/2) has raised concerns over the possibility that this would be a breach of BWM convention, as the water would be taken aboard untreated in port (Article 2 section 8 BWM convention). In addition, it is unclear whether the discharge port will accept this. As per Article 2 section 8 of the BWM convention, it is better to avoid as much uptake of source water species and sediments through treatment at source port only for regular ballast water management.

Testing of type approved BWMS in real-world sediment loads

Over a detailed investigation with Global TestNet (the association of global testing facilities), we found that these systems are mostly tested at real world biological loads (i.e. species) but not at real world sediment loads (i.e. ppm or mg/l of sediment). The IMO G8 performance guidel

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