A study on treatment efficacy of ballast water treatment system applying filtration + membrane separation + deoxygenation technology during shipboard testing.

The efficacy of a BWMS with filtration + membrane separation + deoxygenation technology in treating ballast water was investigated under marine operational circumstances in five shipboard tests. The shipboard tests were carried out between August 2020 and March 2021 onboard a bulk carrier JIN HAI HUA, which sailed between Mawei, Qinhuangdao and Caofeidian in China throughout spring, summer, and fall season. The discharge results in all five tests met the D-2 standard in IMO BWMS Code, with the shortest holding time of less than three days. The BWMS does not involve application of chemicals or generation of by-products, and is considered to be an appropriate choice for certain types of ships.

Recommendations for representative sampling methodologies in ballast water: A case study from the land-based test.

Accurate assessment of ballast water's community composition and organism concentrations is crucial for effective management. Yet, the lack of standardized global sampling methods presents challenges to achieving this objective. Inconsistencies hinder data comparison across regions and vessels, impeding efficient ballast water treatment and discharge regulation. This study conducted land-based tests to establish suitable methodologies. For organisms ≥50 µm and ≥10 µm to <50 µm, the recommended max flow rate is 50 L/min; for <10 µm organisms, 25 L/min is advised to prevent cell damage. Sampling should cover substantial discharge durations. To ensure representation, ≥50 µm organisms require ≥1m3, while ≥10 µm to <50 µm and <10 µm organisms need 20 L. The ultimate aim is standardized methods for assessing ballast water across regions and vessel types, facilitating effective management to curb invasive species and protect aquatic ecosystems.