Towards minimizing transport of aquatic nuisance species in ballast water: Do organisms in different size classes respond uniformly to biocidal treatment?

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.

Recent progress and challenges facing ballast water treatment - A review

The transoceanic movement of non-indigenous microorganisms and organic and inorganic contaminants through the transfer of ballast water of ocean-going vessels can be considered highly likely. The introduction of contaminants and non-indigenous microorganisms can cause changes in indigenous microorganisms, marine species, and biota, which can create problems for the ecology, economy, environment, and human health. This paper compiles and presents ballast water treatment system concepts, principles of inactivation mechanisms used, and the advantages and challenges of the treatment technologies. In addition, the paper aims to draw attention to the relationship between various organisms and the individual mechanism to be inactivated, including the effect of external factors (e.g., pH, salinity, turbidity) on inactivation efficiency. This review can assist in the choice of a suitable ballast water treatment system, taking into account the water conditions (e.g., pH, temperature, salinity) and indigenous species of the maritime areas where the ships intend to operate. This review also provides information describing the responses of the various organisms to different treatment techniques.

Feasibility of potable water generators to meet vessel numeric ballast water discharge limits

Ballast water is taken on-board vessels into ballast water tanks to maintain vessel draft, buoyancy, and stability. Unmanaged ballast water contains aquatic organisms that, when transported and discharged to non-native waters, may establish as invasive species. Technologies capable of achieving regulatory limits designed to decrease the likelihood of invasion include onboard ballast water management systems. However, to date, the treatment development and manufacturing marketplace is limited to large vessels with substantial ballast requirements. For smaller vessels or vessels with reduced ballast requirements, we evaluated the feasibility of meeting the discharge limits by generating ballast water using onboard potable water generators. Case studies and parametric analyses demonstrated the architectural feasibility of installing potable water generators onboard actual vessels with minimal impacts for most vessel types evaluated. Furthermore, land-based testing of a potable water generator demonstrated capability to meet current numeric discharge limits for living organisms in all size classes.