Ballast Water Management Systems Research Articles

Examining effects of sample concentration on estimates of live phytoplankton abundance

With the entry into force of the International Maritime Organization's International Ballast Water Management Convention in September 2017, ships have begun to install and operate onboard ballast water management systems (BWMS) to reduce the number of live organisms in ballast water. Scientific methods were developed to assess the effectiveness of BWMS at reducing the number of live organisms in ballast water. However, detecting low organism concentrations in treated ballast water is challenging when considering the small sample volume (6 mL) analyzed for organisms in the 10–50 μm size class. The volume analyzed can be increased by concentrating the sample prior to analysis, but it is important to assess the effects of the sample concentration method due to potential cell loss experienced during the concentration step. Therefore, laboratory experiments were conducted to assess the effects of a gravity filtration method to concentrate samples to a factor of 40:1. Experiments were conducted for both low and high organism abundances. For unpreserved samples at low organism abundances (∼10 cells mL−1), concentrated samples had on average 31% fewer live cells mL−1 than unconcentrated samples for four out of five experiments. At high organism abundances (≥ 120 cells mL−1), unpreserved concentrated samples had on average 55% fewer live cells than unconcentrated samples. Alternatively, with preserved samples at low organism abundances, concentrated samples had on average 4.5× more cells than unconcentrated samples. At high organism abundances, concentrated samples had on average 6.4× more cells than unconcentrated samples. Differences were also observed between preserved and unpreserved samples. These findings can help to improve ballast water monitoring procedures and BWMS assessments, addressing a critical challenge to maritime environmental protection.

Systematic Considerations for a Ballast Water Treatment System (BWTS) Retrofits: A Review

As a country that has more than half of the country's total territorial waters, Indonesia is highly dependent on shipping activities. Therefore, knowledge of policy updates for each ship from IMO must also be taken into account, one of which is the policy regarding the Ballast Water Management System, which requires every ship to be installed with a Ballast Water Treatment System in order to achieve the goal of a green environment in voyage areas by inhibiting the spread of microorganisms that endanger the area that is caused by ballast water. This regulatory update then creates problems, especially for ships that have been operating for a long time, because the ship has to comply with the standards for D-1 and then also have to comply with the D-2 standards according to the time specified in the convention. So, this review article will discuss the solution to the issues with retrofitting ballast water treatment systems as the addition of a new system to the existing system on a ship that has sailed and pay attention to conceptual aspects consisting of considerations and operations to find the type of ballast water treatment that suits each ship's needs by analyzing the advantages and disadvantages of each technology type method. There is also consideration for several stages that are commonly used to determine the type of treatment, starting with assessment and planning requirements, selection of space, compliance with BWMS regulations, selection of the ballast water treatment system method, engineering drawing, installation planning, and commissioning. Apart from that, several related innovation considerations were also discussed, including the development of alternative treatment technology, which has the potential for efficiency both in operational aspects and safety standards. Based on research developments, retrofitting the Ballast Water Treatment System with the ultra-violet (UV) treatment is well known as the common treatment beside the electrolysis treatment. The results obtained show that the ultra-violet (UV) method is one of the most efficient treatments when viewed from the way it works and the time duration for the treatment process. This proves that ultra-violet treatment can produce maximum efficiency if the selection of needs and consideration of maximized aspects also exceed the safety aspect as well.

Biological testing of ships’ ballast water indicates challenges for the implementation of the Ballast Water Management Convention

Ships’ ballast water and sediments are vectors that contribute to the unintentional spread of aquatic non-native species globally. Ballast water management, as well as commissioning testing of ballast water management systems and compliance monitoring under the regulations of the International Maritime Organization (IMO) aim at minimizing the unwanted spread of organisms. This study compiles data for treated ballast water samples collected and analyzed from 228 ships during 2017–2023. The samples were collected from the ballast discharge line or directly from the ballast tank for enumeration of living organism concentrations in the categories of ≥50µm and <50 to ≥10µm -sized organisms, as well as indicator microbes in comparison to the ballast water performance standard of the IMO (Regulation D-2). In addition, several ship-specific factors were examined to infer potential factors affecting compliance rates. Nearly all ships were compliant with the ballast water performance standard for indicator microbes and <50 to ≥10µm -sized organisms, whereas almost half of all samples exceeded the limit of ten viable organisms m-3 for the ≥50µm -sized organisms. Compliance testing results did not differ significantly between sampling years, indicating that compliance rate did not change through time. The rate of compliance was higher for commissioning testing than compliance testing. Clear ship- or system-specific factors that lead to compliance or non-compliance were not detected, even though type of ballast water management system, filter mesh size associated with the system and source of ballast water affected compliance significantly either for the samples taken from the discharge line, or ballast tank. As compliance did not improve significantly over time, compliance testing of ships’ ballast water should be undertaken to ensure that the systems remain operational after commissioning and ships meet requirements of the D-2 standard. Furthermore, the study outcomes promote further research on the efficiency of filter mesh sizes and different filtration units associated with ballast water management systems, to improve mechanical removal of larger organisms. Finally, as several ships exceeded the compliance limit by hundreds or thousands of living organisms, technological advancements and operational measures may be needed to improve the overall reliability of ballast water management.

Simulated Testing of the Characteristics and Environmental Impacts of Disinfection By-Products Generated by Ballast Water Management Systems in Ports during Phytoplankton Blooms

Ballast water management systems (BWMSs) using active substances (AS) have been subjected to land-based tests with artificially increased dissolved organic matter (DOM) and cultured species according to the International Maritime Organization G9 guidelines before the BWMS Code revision. Therefore, data on the environment risk assessment (ERA) of disinfection by-products (DBPs) for actual port DOM and natural species are limited. This study was conducted using seawater from Jangmok Bay, South Korea, during a phytoplankton bloom. In treated water with a high biological content (Group A), the DBPs concentration increased as the initial AS concentration increased. However, in treated water with a low biological content (Group B), the DBPs concentration did not increase as the initial AS concentrations. The higher the residual AS concentration on day 5, the more the DBPs concentration increased, and the composition ratio of the DBPs was also affected. The ERA to individual DBP was evaluated as low given <1 for the ratio of the predicted environmental concentration to the predicted no-effect concentration in port environments exposed to DBPs in discharged ballast water. This result may suggest that the ERA of IMO G9 performed with cultured species and additives could substitute the outcome obtained with natural plankton assemblages.

Diversity variation of zooplankton and phytoplankton communities in ship ballast water during the maiden voyage

The transfer of ships' ballast water poses a risk of biological invasion to the aquatic ecosystem. Although the ecological risks posed by ships' ballast water have been reduced by the installation of type-approved Ballast Water Management System (BWMS) equipment, some treated ballast water still does not meet the requirements of the D-2 standard. Here, experiments were conducted to investigate the trends of phytoplankton and zooplankton in ship ballast water during different ship’s maiden voyages. The results showed that there are some differences in the trends of the abundance of zooplankton and phytoplankton in the ballast water samples of two ships, i.e., the “Zhang Jian” and the “Song Hang”. The abundance of zooplankton in the ballast water samples of the “Zhang Jian” showed an increasing and then decreasing trend. An explosion of phytoplankton, predominantly Chlorophyta and Cyanophyta, was observed in the ballast water samples of the “Zhang Jian” at the end of the voyage. The abundance of phytoplankton and zooplankton in the ballast water samples of the “Song Hang” showed a decreasing trend. The study aims to clarify the trends and composition characteristics of plankton in ballast water in different ships to promote the effective management of ballast water and protect the ecological environment of port waters.

Ballast water management systems protect the Great Lakes from secondary spread of non-indigenous species

Ballast water management systems protect the Great Lakes from secondary spread of non-indigenous species

Evaluate the compliance of ballast water management system on various types of operational vessels based on the D-2 standard

The transfer of ship ballast water poses significant risks to the aquatic ecosystem and human health. To mitigate the influences of non-native species, ballast water management systems (BWMS) have been installed on international ships to ensure proper treatment of ballast water before discharge. This study investigates whether ballast water discharges managed by BWMS meet the requirements of the D-2 standard for organisms in different size classes. Representative ballast water samples were collected from 28 ships (a total of 20 different BWMS) arriving in Shanghai during the period 2020–2022. Results have shown that two samples (7.1 %) exceeded the D-2 Standard. The compliance rates varied among different vessel types, with cargo vessels achieving a compliance rate of 81.8 %, while LNG vessels and container vessels achieved 100 % compliance. The potential to achieve higher levels of ballast water management will increase as crews improve their skills in operating BWMS and BWMS is further developed.

Inherent lack of CMFDA/FDA staining in certain algae and its implication for ballast water testing

The approved method for testing the efficacy of ballast water management systems with respect to killing 10–50 μm organisms uses movements of the organisms or the vital stains CMFDA/FDA. The present study demonstrates that certain freshwater coccoid chlorophytes, known or suspected to contain a highly resistant cell wall component (algaenan), stain poorly with CMFDA/FDA, resulting in false negatives. The staining rates for the most dominant species were determined and were approx. 3–70 %. The use of Crystal Violet as an indicator for the presence of algaenan gave inconclusive results. The number of the 10–50 μm organisms in a small pond was found to be 10,183 organisms/mL (Lugol's fixed sample) vs. 2335 organisms/mL (CMFDA/FDA-stained sample). Using the staining rates obtained, it was estimated that the number of false negatives could make 40–50 %. The implications for biological performance evaluation of ballast water management systems are discussed.

Ballast water management systems (BWMS) Type approval: A new application for flow imaging microscopy (FlowCAM)

Ballast water is a well-known vector for non-indigenous organisms’ introduction, causing harm to ecology, economy, and human health. Following International Maritime Organization (IMO) regulations, all vessels should use an approved ballast water management system (BWMS) to reduce the transfer of organisms. As a result, rapid and accurate methods are needed for effective ballast water management. In this paper, we examined the applicability of a flow imaging microscopy (FlowCAM) for detecting phytoplankton in land-based and shipboard BWMS tests. The results showed that FlowCAM failed to recognize and tended to underestimate the abundance of some species in comparison to a fluorescence microscope. However, the abundance of many other species or genera estimated by the two methods was similar. Generally speaking, although some discrepancies were observed, considering the efficiency of FlowCAM in capturing images and measuring the abundance of particles, FlowCAM may become a promising technology in BWMS Type Approval.

Onshore ballast water management systems: National perspectives

The present paper focuses on ballast water management systems (BWMS) in line with the Ballast Water Management Convention, aiming to prevent marine pollution from harmful alien species transported through ships’ ballast water. Three approaches of BWMS are considered: Ballast water exchange, Onboard and Onshore systems. Solutions regarding ballast water reception and treatment are proposed, including several options: for ports that are equipped with ballast water reception facilities (BWRFs); for ports not equipped with BWRFs and for companies with onshore facilities (OBWRFs).Thoroughly examined in the paper is the applicability of national onshore BWMS inclusive specifically of the expected users of the OBWRFs; suggested stakeholder groups involved in the process and their responsibilities; step by step procedure; documentation of the procedure related to the main parties - the Shipowner/ captain, Port authority, the company with OBWRFs. It has been found out that OBWRFs are more suitable to be applied on national level, bearing in mind that most of the Bulgarian ports are limited to increase their working area. Further research should be carried out about the possible location of the OBWRFs with regard to the necessary infrastructure, equipment, restricted zones, etc.

Examining the performance of three ballast water compliance monitoring devices for quantifying live organisms in both regulated size classes (≥50μm and ≥10-

A number of ballast water compliance monitoring devices (CMDs) have been made commercially available to verify the efficacy of ballast water management systems by quantifying the living organisms for both plankton size classes (≥50μm and ≥10-<50μm). This study aimed to examine whether new CMDs can provide a reliable indication of compliance regarding Regulation D-2 and to evaluate their performance for indicative analysis of organisms by assessing their accuracy (comparison to microscopy) and precision (comparison within measurement). Challenge fresh water samples were collected in four locations of Lake Ontario, Canada, whereas marine challenge water samples were collected around the Bay of Fundy, New Brunswick, Canada. Ballast water samples were collected from ships visiting several ports across Canada. Overall, accuracy was higher (>80%) in estimating organisms from prepared-challenge water (Ballast Eye and BallastWISE) than from ballast water samples (>70%) (B-QUA only). The sensitivity ranged from 50 to 100% for the ≥50μm organism size class, whereas for the ≥10-<50μm organism size class, it was higher for freshwater samples (>75%) than for marine samples (>50%). The performance of CMDs should be assessed under real-world conditions for a better understanding and to improve their use.

Assessing the effectiveness of filtration + UV-C radiation for the treatment of simulated ballast water at various holding times.

In recent years, the issue of invasive alien species brought on by ballast water has drawn increasing attention, and advances in ballast water treatment technologies have been made. One of the most popular combined ballast water treatment technologies utilized in ballast water management systems (BWMSs) globally is filtration + UV-C radiation. During the actual voyage of the ship, ballast water is treated by the BWMS and then enters the dark ballast tanks until the ballast water is discharged. Marine organisms are able to complete DNA damage caused by UV radiation in dark ballast tanks. Therefore, the length of holding time affects the effectiveness of the BWMS in treating ballast water. The objective of this study was to examine the efficacy of filtration + UV-C irradiation treatment at different holding times for the removal or inactivation of phytoplankton and zooplankton populations during simulated ballast water treatment. Results indicate that the holding time after the filtration + UV-C radiation treatment increased the inactivating efficacy, especially for zooplankton in natural seawater. For phytoplanktons in ballast water, the strongest impact on the treatment efficacy was reached with a holding time of 24 h.

Evaluating the treatment performance of filtration & real-time UV irradiation processes for bacteria and pathogens in fresh ballast water

Ballast water (BW) is fresh water or seawater taken onboard to stabilize ships. By traveling with the vessels, different species can be introduced into a new area, which has potential impact on human health, economy, and environment. Bacteria are transferred in large numbers through BW. Owing to their diversity and potential pathogenicity, they could pose a direct threat to the prevailing microbiome in the recipient waters and human health. The aim of this paper is to examine the effects of real-time ultra-violet (UV) irradiation on the survival, activity, and diversity of bacterioplankton in fresh water. The treated water was held in the treatment tanks for one day or five days before discharged. After treatment, the density of total viable bacteria and indicator bacteria decreased significantly in discharge water compared with control water, and the density of indicator bacteria met the D-2 standard. The sequencing of 16S rRNA amplicons showed that α-proteobacteria was dominant in Inlet water. In the treated water, γ-proteobacteria was dominant in UV_PD_1d, while α-proteobacteria became the most abundant class again in the UV_PD_5d. Shannon and Simpson indices confirmed the declining trend in bacterial diversity. Further, our result indicated that real-time UV irradiation was likely to cause the change of assemblage of bacteria, and there were still several pathogen bacteria after treatment. By monitoring the physicochemical parameters of ballast water, we found that pH positively correlated with the dominant phylum Proteobacteria. This study provides a further idea for type approval of ballast water management systems.

Improvement in compliance of ships' ballast water discharges during commissioning tests

The number of ships installing ballast water management systems (BWMS) has risen steeply since the Ballast Water Management Convention entered into force. Since June 2022, biological testing is required during commissioning to verify compliance with the Convention. Data from 676 tests (from 2019 to 2022) show substantial improvement over time: the failure rate decreased from ~20 % to ~6 %. Notably, nearly all failures occurred in the largest size class of organisms (≥50 μm). Interestingly, proxy measurements suggest that high concentrations of living organisms in uptake water did not cause the failures. Also, failures determined using “indicative” analysis (here, adenosine triphosphate, ATP) were typically not confirmed by “detailed” analysis (microscopy), suggesting that ATP limits are over-precautionary. Finally, discharges containing high levels of Total Residual Oxidants (TRO) decreased over time. These data highlight the need for ongoing testing—focusing at least on organisms ≥50 μm—to minimize environmental risks from organisms transported in ships' ballast water.

Analysing vessel traffic and ballasting trends in the port of Pago Pago, American Samoa from 2004 to 2021

Commercial shipping has been associated with many introductions of marine invasive species globally. Unintentional transport stowaways in ship ballast water and biofouling account for the most unintentional marine introductions globally. Understanding vessel traffic and ballasting behaviours can aid managers in identifying research and biosecurity gaps. We provide a quantitative baseline assessment of commercial vessel activities in American Samoa between 2004 and 2021. Vessel traffic and ballast water data were downloaded from the National Ballast Information Clearinghouse and examined in R. Since reporting began, vessel arrivals in the territory gradually increased each year, reaching a peak of 229 vessels in 2017. Over a third of all arrivals are container ships. Although commercial vessels arrive from ports all over the world, most come from and remain in the South Pacific. Containers and tankers were responsible for most of the ballast water discharges in the territory. The use of alternative ballast water management systems began in 2015 and increased dramatically in the following years. Though American Samoa's vessel traffic patterns are similar with the United States as a whole, we highlight key differences in this small, yet important, South Pacific port. This article highlight the importance of assessments at individual ports to better inform biosecurity decisions with an emphasis on regional biosecurity measures and communication among the Pacific Islands.

Hybrid multiple-criteria decision-making for bulk carriers ballast water management system selection

Ballast water is essential in maritime transport to maintain the stability of navigation. However, alien invasive species brought by ballast water may jeopardize the integrity of the aquatic environment, including marine, brackish and freshwater. Therefore, the International Maritime Organization (IMO) established stricter ballast water discharge standards after 8 September 2024. Under the new regulations, selecting an appropriate ballast water management system (BWMS) might pose a challenge for shippers. In this study, we worked with several domain experts and applied the fuzzy analytical hierarchy process (FAHP) to set up two decision support frameworks for bulk carriers larger or smaller than 40,000 gross tons. Results indicate the assessment criteria and their associated weights. The “Ballast Water Management System Manufacturer” criteria was the priority consideration for large vessels, whereas the “Space” criteria was the priority consideration for small vessels. We also applied TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) to sort the advantages and disadvantages between different systems. The results show that regardless of how large or small the vessels are, the ozone treatment system is favored by shippers due to the higher confidence placed in this industry. Validating these methods can provide valuable decision-making support for shippers to select a suitable BWMS.

Ballast Water Problem: Current Status and Expected Challenges

Transporting non-native species in ballast tanks has been a major challenge over the years. The number of surviving species in the host environment is quite small compared to those of all introduced. However, even a single species can cause great harm to the environment, economy, and public health. Ballast water treatment issues are difficult and complex as the performance of the treatment is highly affected by the variable characteristics of the seawater. In addition, targeted organisms are in a wide spectrum. The International Convention on the Control and Management of Ship Ballast Water and Sediments requires ships to manage ballast water with a Type Approved System in compliance with the Ballast water discharge standard defined in the Convention. The Ballast Water Management Systems Approval (G8) Guide was revised in 2016 and accepted as the BWMS Code (Ballast Water Management Systems Approval Code) as the mandatory regime in 2018. According to the implementation schedule of this mandatory approval regime, the ballast water management system installed on or after 28 October 2020 must be type-approved according to the IMO’s revised G8 requirements. Several systems use different methods with their limitations. However, the ballast water problem does not seem to end only with the installation of the systems on ships. Although substantial international progress has been made in ballast water management (both technically and regulatory), there are still several issues regarding effectiveness, compliance monitoring, and the environment.

The effect of filtration and electrolysis on ballast water treatment

Ballast water is required to be treated to reach D-2 standard according to the International Maritime Organization (IMO). Filtration and electrolysis are important technologies for ballast water management systems (BWMS). However, the clogging of filters during the operation of BWMS leads to significant system trips and downtime. In this paper, a mesoscale experiment system was set up and the effects of filtration on ballast water treatment using electrolysis were investigated. The results showed pore size of filter had significant effect on filtration efficiency, total residual oxidant (TRO) decay and inactivation efficacy. The filtration efficiency of filter with 50 μm pore size was over 80% for ≥50 μm organisms. For 200–2000 μm pore sizes (200 μm, 500 μm, 1000 μm and 2000 μm), the filtration efficiency was less than 10%. The effect of filtration on TRO depended on pore size and holding time. Our results indicated that increasing pore size of electrolysis may not a good way for new BWMS design. If electrolysis was applied alone to treat ballast water, higher initial TRO concentration was needed. In our investigation, the initial TRO was more than 12 mg/L.

Characteristic and Relative Environmental Risk of Disinfection by Products Associated with Simple Glucose or Naturally Occurring Algal Organic Matter as Tested in Ballast Water Treatment System

To prevent the invasion of alien species, the International Maritime Organization and the United States Costal Guard require that a ballast water management system (BWMS) be installed on ships to treat the ballast water before discharging it. BWMS technologies use active substances, which create disinfection by-products (DBPs) during ballast water treatment. This study compared the characteristics of DBPs generated in the treatment of commercial glucose with those of algal organic matter (AOM) derived from field-collected phytoplankton using NaOCl as the active substance. During the treatment of AOM, a greater variety and higher concentrations of DBPs were generated than for glucose. For AOM in freshwater, bromoform and dibromoacetic acid were dominant because of the bromine ions present in the phytoplankton. During the treatment of glucose, the ratio of the predicted environmental concentration to the predicted no-effect concentration of dibromoacetonitrile and chloropicrin exceeded 1, indicating a potential environmental risk. Whole effluent toxicity (WET) testing showed that the chronic toxicity of phytoplankton and the total DBP concentration were highest in marine water with AOM. In addition, the results of WET testing suggested that the concentrations of haloacetic acids (HAAs) and haloacetonitriles (HANs) were important indicators for the evaluation of environmental risk. Therefore, to evaluate the risk of DBPs in international ports where phytoplankton outbreaks frequently occur, it is important to monitor not only the total DBP concentration but also the total HAA and HAN concentrations.

UV-LEDs combined with persulfate salts as a method to inactivate microalgae in ballast water

The Ballast Water Management Convention (BWMC) establishes limits for viable organisms in discharged ballast water. UV-based ballast water management systems (BMWS) are among the most common, especially those with low pressure (LP) and medium pressure (MP) mercury lamps. An interesting alternative to mercury lamps could be UV LEDs that have been developing over recent years. UVA, UVB, and UVC LEDs have been tested as a method to inactivate microalgae in ballast water. For this study, the diatom Phaeodactylum tricornutum was selected as a target organism. Comparing the D2 (dose required to achieve two log reductions) for P. tricornutum from different UV treatments, it was observed that UVC LEDs were 74.2 % more efficient than UVB LEDs and, compared with previous studies, 48.1 % more efficient than UVC LP mercury lamps. If a five day dark post-treatment was combined with the UV irradiation to avoid photoreactivation, UVC LEDs were 90 % more efficient than UVB LEDs and, compared with previous studies, 36.8 % more efficient than UVC LP mercury lamps. No damage with or without photoreactivation was caused by UVA irradiation with doses up to 4·104 mJ cm−2. The combination of peroxymonosulfate (PMS) with UVA, UVB and UVC LEDs did not significantly increase the inactivation, and the combination of the peroxydisulfate (PDS) with UVC LEDs slightly decreases the inactivation compared with UVC irradiation alone. In conclusion, UVC LEDs were the most efficient for inactivating P. tricornutum, and the combination of PMS and PDS with UV LEDs did not notably improve it.