Ballast Water Treatment Research Articles

Insights to ballast water: metagenomics as a pressing priority

Metagenomics represents a pivotal development in genomics, offering unprecedented insights into a diverse spectrum of microorganisms, including bacteria, viruses, and fungi, that were previously challenging or impossible to study outside natural environments. Its applications span a remarkable range, from exploring cosmic entities to the depths of our oceans, incorporating numerous analyses. Yet, its utilization in the context of ballast water analysis remains scarce. This highlights the crux of the present review, which aims to showcase the need for metagenomics in ballast water analysis. As is known, ballast water is essential for maintaining ship stability under no cargo conditions or during adverse weather, with daily global movements estimated to be between 3 to 10 billion tonnes. A single bulk cargo ship can transport up to 60,000 tonnes of ballast water for a 200,000-tonne load. It is estimated that over 7,000 species are transported globally in ships' ballast water daily, posing significant ecological risks when these organisms are discharged into new environments where they can become invasive species, disrupting local ecosystems, economies, and human health. Despite the International Maritime Organization setting D-2 standard guidelines and endorsing several ballast water management practices for its safe discharge, the issue persists. This underscores the necessity of employing metagenomics to enhance the monitoring of microbial content in ballast water. The review summarizes some research conducted worldwide to analyze ballast water by metagenomics, all exhibiting diverse microbes, including potent pathogenic bacterial and viral forms. The findings support our view, making metagenomics an invaluable tool to monitor ballast water treatment effectiveness in compliance with evolving environmental regulations. Though the challenges facing metagenomic applications—namely cost, complexity, and the need for comprehensive reference databases—are significant, they will surely be surmountable considering continual technological and methodological advancements. Embracing metagenomics offers a pathway to not only address the ecological threats posed by ballast water transfers but also to safeguard the future of global shipping industries.

Legal challenges of regulating cross-border nuclear pollution from ship ballast water under the background of fukushima wastewater release and China’s response

The Japanese government has initiated plans to release water contaminated The international community has yet to fully recognize the accelerated spread of nuclear-contaminated water through ship ballast water along the Japanese route. This increases the risk of nuclear exposure for crew members and poses ecological and environmental contamination risks to port waters, inland seas, and rivers. The lack of international attention to the marine nuclear safety crisis caused by nuclear pollution from ballast water, along with the absence of corresponding legal prevention and control mechanisms and technical safeguards, remains a critical issue. From the perspective of international law, preventing the spread of Fukushima wastewater through ship ballast water faces numerous legal challenges, including disputes over the applicability of conventions, the jurisdiction of international organizations, and mechanisms for cross-border accountability for marine nuclear pollution. As a major shipping nation adjacent to Japan, China faces significant risks of nuclear pollution from ballast water along the Japanese route. To counter such risks, it is recommended to propose measures through the International Maritime Organization to elevate international attention. Moreover, refining ballast water regulatory frameworks, establishing monitoring and warning mechanisms specific to nuclear pollution from ballast water, improving the technical capabilities of ballast water treatment systems, and promoting international cooperation in monitoring marine environments and preventing pollution are also advisable.

Phytoplankton distribution pattern and its implication for the establishment of land-based ballast water treatment technology and test facility in tropical waters

The present study was carried out to investigate the phytoplankton distribution in tropical waters and its implication for establishing land-based ballast water treatment technology and test facility (BWTT-TF) as per the International Maritime Organization (IMO) guidelines. Samples were collected from the Swarnamukhi estuary (SE) and coastal locations on the east and west coast of India. The maximum phytoplankton density in the size group of ≥10 and < 50 μm was recorded as 3002 cells/mL in estuarine waters and 172 cells/mL in coastal waters. Among the phytoplankton, Bacillariophyta and Pyrrophyta were observed at all locations, whereas Ochrophyta and Chlorophyta were found only at specific locations or during specific periods. According to IMO guidelines, the minimum required number of species (5) was observed at all the locations, but the minimum number of phyla (3) was not found at some locations. The IMO minimum required phytoplankton density (>1000 cells/mL) was observed only during the bloom period, whereas it was about 5–50 times lower during other periods. Taxonomic distinctness indices were used to examine the diversity beyond the conventional species count. The study found that the Buckingham Canal and Swarnamuki River upstream among the SE locations, and coastal stations of Pamanji and Tirunelveli among the coastal locations, are suitable sites to establish land-based BWTT-TF. Since the results indicate that achieving the IMO specified size group of ≥10 and < 50 μm density in tropical waters was possible only during the bloom period, culturing phytoplankton surrogates and concentrating naturally available phytoplankton are recommended as alternate methods for establishing land-based ballast water treatment technology and test facilities.

Viability assessed with the most probable number dilution culture method after chemical treatment of ballast water reveals the presence of false negatives from an approved vital stain method

The present study compares the CMFDA/FDA + motility- and the Most Probable Number (MPN) Dilution Culture + Motility methods for testing the viability of ≥10–<50 μm organisms in chlorine treated ballast water. The results of both methods were within the regulatory compliance criterion <10 organisms/mL, but the MPN-method revealed that growth-outs did occur. While the CMFDA/FDA method showed <0.5 organisms/mL, the MPN-method gave approx. 6 organisms/mL. This demonstrated that false negatives, i.e. living but not stained organisms, may occur when using the CMFDA/FDA-method for compliance testing of chemical treated ballast water. Organisms surviving the treatment were primarily the dinoflagellate Scrippsiella sp. and various coccoid chlorophytes present in a brackish- and freshwater test, respectively. It is suggested that their resilience to the chemical treatment is the ability to transform into a temporary cyst (Scrippsiella sp.) or the presence of a chemical resistant cell wall (certain chlorophytes).

A flow-through Ti4O7 membrane electrode for ballast water treatment: Performance, mechanism, and comparison with Ti/RuO2-IrO2 electrode

Electrochemical Advanced Oxidation Processes (EAOPs) present a promising solution for ballast water treatment. However, due to the extremely short half-life of reactive oxygen species, the disinfection active zone is limited to the surface of the electrode, resulting in low disinfection current efficiency of EAOPs. To address this challenge, this study developed a flow-through electrochemical disinfection system utilizing a Ti4O7 membrane electrode. A comparative analysis was conducted against a conventional Ti/RuO2-IrO2 electrode to assess the Ti4O7 membrane electrode’s efficacy in ballast water disinfection. The flow-through mode significantly increased the probability of contact between E. coli and the surface of Ti4O7 membrane electrode, consequently leading to a notable increase in the inactivation rate from 1.05 min−1 to 1.63 min−1, at a current density of 20 mA/cm2, at a Cl- concentration of 16.5 g/L, and an initial E. coli concentration of 107 CFU/mL. Notably, at low current densities, the Ti4O7 membrane electrode exhibited superior disinfection performance compared to the Ti/RuO2-IrO2 electrode. The predominant disinfection active species in the Ti4O7 membrane electrode system were identified as reactive oxygen species, particularly •OH and •O2–, contrasting with the abundant generation of active chlorine species (ACSs) observed in the Ti/RuO2-IrO2 electrode system. Both electrode systems demonstrated the ability to disrupt the cellular structure of E. coli. However, due to the sustained effectiveness of ACSs, the degradation rate of total protein in the Ti/RuO2-IrO2 electrode system (40.53 %) surpassed that of the Ti4O7 membrane electrode system (12.39 %). Despite the minimal concentration of ACSs in the Ti4O7 membrane system (0.02 mg/L), no bacterial regeneration was observed, highlighting the efficacy of the Ti4O7 membrane electrode in preventing bacterial regrowth. This study elucidated a free radical-based disinfection mechanism for the Ti4O7 membrane electrode, affirming its feasibility for ballast water disinfection purposes.

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.

Sustainability in maritime transport: Selecting ballast water treatment for a bulk carrier

The study provides a comprehensive assessment of ballast water treatment systems (BWTS) selection regarding crucial parameters such as energy efficiency, fuel consumption, and CO2 emissions. The focus of the study is investigating the environmental impacts of BWTS and how these impacts can be considered in decision-making processes. In this context, it comprehensively analyzes the importance of decision-making parameters and the environmental consequences of BWTS applications. The potential impacts of the system on the sustainability of the maritime industry are highlighted. In this context, seven different BWTSs for a bulk carrier of 83,000 deadweight tonnes are evaluated using Analytical Hierarchy Process (AHP) and Preference Ranking Technique by Similarity to Ideal Solution (TOPSIS). According to the analysis, Operational Expenditure (0.314508), Capital Expenditure (0.249515), and Capacity (0.159952) are the most critical factors. Among the seven systems analysed, product G (0.8561137) emerges as the most suitable option. The analysis represents 3% of total emissions (456.5 tonnes CO2) and highlights the impact of BWTS on CO2 emissions. The results underline the need for innovative approaches aimed at ensuring the long-term sustainability of the maritime industry.

ELECTROCOAGULATION SYSTEM FOR TREATMENT OF BALLAST WATER

This study aimed to determine the removal of hazardous materials in ballast water by using an electrocoagulation (EC) system. This research was carried out on January 16 – June 15 2023 in Batam City. Ballast water was supplied by tanker ships anchored at 5 ports in Batam Island, namely Batam Centre, Sekupang, Nongsapura, Telaga Punggur, and Batu Ampar. The ballast water was collected and processed through an electrocoagulation system at PT. Batam Air Cargo Village, Batam. Meanwhile, the quality of the treated ballast water was examined by PT. Mutuagung Lestari Batam, Batam, Indonesia. If the laboratory test results meet the requirements, then the remaining ballast water can be disposed of into nature. However, if the test results are not met, then the ballast water is re-processed and channeled to the mixing tank. The physical parameters of the treated ballast water showed a temperature of 28oC, total dissolved solids (TDS), and total suspended solids (TSS) of around 140 and 11 mg/L respectively. The main heavy metal content of ballast water after the electrocoagulation process showed cadmium (&lt; 0.001 mg/L), chrome (&lt; 0.02 mg/L), mercury (&lt; 0.0001 mg/L), lead (&lt; 0.005 mg/L), copper (0.14 mg /L), zinc (0.31 mg/L), and arsenic (&lt; 0.0001 mg/L). The physical parameters of the treated ballast water showed a temperature of 28oC, total dissolved solids (TDS), and total suspended solids (TSS) of around 140 and 11 mg/L respectively. The main heavy metal content of ballast water after the electrocoagulation process showed cadmium (&lt; 0.001 mg/L), chrome (&lt; 0.02 mg/L), mercury (&lt; 0.0001 mg/L), lead (&lt; 0.005 mg/L), copper (0.14 mg /L), zinc (0.31 mg/L), and arsenic (&lt; 0.0001 mg/L). Other chemical and biological parameters that were also measured included sulfide (&lt; 0.002 mg/L), fluoride (0.11 mg/L), chlorine (0.05 mg/L), ammonia (0.78 mg/L), nitrate (&lt; 0.05 mg/L), nitrite (&lt; 0.004 mg/L), total nitrogen (0.78 mg/L), BOD5 (22.69 mg/L), methylene blue active compound (0.732 mg/L), phenol (0.001 mg/L), oil and fat (1.032 mg/L), pH (7.13), and total coliform (615 MPN/100). All parameters showed that the hazardous content of electrocoagulated ballast water waste has met the quality standards for ballast water waste. It has also been tested to process other liquid waste. So, it is very promising to be developed for other waste processing needs in the future.

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.

Enhanced Fenton-like catalysis through in-situ bismuth defection in Bi/CuBi2O4: Vacancy mechanisms

Alleviating the concentration of hazardous bacteria by photocatalysts is an efficient way for treating ballast water. In this work, we present the synthesis of in-situ Bi vacancies on Bi/CuBi2O4, which is assisted by H2O2 for Fenton-like photocatalytic potential in deactivating marine microorganisms in natural seawater (Yellow Sea, China), the optimal Bi vacancy content (3BCBO) is determined and exhibits superior photocatalytic inactivation performance, additional H2O2 activation enhances the production of •OH for comprehensive oxidation, with •OH confirmed as the dominant reactive species. Density functional theory (DFT) calculations highlight the synergistic of vacancies and metallic Bi play a pivotal role in decreasing the energy barrier of H2O2 adsorption for •OH improving production, promotes efficient separation of charge carriers and utilization of visible light, the co-effect of metallic Bi nanoparticles and bismuth defection mechanisms effectively inhibit the madness thriving of marine microorganisms, this work offers an ideal and promising perspective for ballast water treatment on ships.

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 &amp;lt;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 &amp;lt;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.

Removal of algae from ballast water by cationic flocculant-composite titanium xerogel coagulant: Differences in freshwater and seawater

The treatment of ballast water has been garnering increasing attention, with planktonic algae removal being a crucial part. Coagulation has been demonstrated as an effective method for algae removal, albeit few coagulants exhibit excellent coagulation performance in both freshwater and seawater. To address this issue, the cationic flocculant poly dimethyl diallyl ammonium chloride (PDADMAC) was composited with titanium xerogel coagulant (TXC), abbreviated as PT. Using the algae Cyclotella meneghiniana as the research object, the algal removal performance and mechanisms of PT in freshwater and seawater were investigated. Cell integrity, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content of C. meneghiniana during floc storage were also evaluated. The PT composite coagulant exhibited excellent coagulation performance in both freshwater and seawater. Its algal removal ability was superior to TXC and the commercial coagulants polyaluminum chloride (PAC) and polymerized ferrous sulfate (PFS), with removal rates for C. meneghiniana reaching 98.3 % in freshwater and 98.4 % in seawater at a 80 mg/L dosage. PT also exhibited excellent removal performance over wide dosage and pH ranges. PT acted via distinct coagulation mechanisms in freshwater and seawater, with charge neutralization and bridging played major roles in freshwater and sweeping being important in seawater. The floc storage experiment indicated that the coagulation process did not directly lead to algal cell fragmentation, but PT accelerated and exacerbated oxidative stress and oxidative damage to algal cells during floc storage. Furthermore, PT also showed excellent removal performance for the marine diatom Skeletonema costatum and the freshwater cyanobacteria Cylindrospermopsis raciborskii. This work not only provides a novel approach for algae removal in ballast water, but also enhances our understanding of the coagulation behavior of titanium-based coagulants in different water environments.

Rapid detection of microalgae cells based on upconversion nanoprobes.

The quantification of microalgae cells is crucial for the treatment of ships' ballast water. However, achieving rapid detection of microalgae cells remains a substantial challenge. Here, we develop a new method for rapid and effective detection of microalgae concentration by utilizing upconversion nanoprobes (UCNPs) of NaYF4:Er3+,Tm3+. Three ligands, carboxylated methoxypolyethylene glycols with 5000 and 2000 molecular weights (mPEG-COOH-5, mPEG-COOH-2) and D-gluconic acid sodium salt (DGAS), were used to convert hydrophobic UCNPs into a hydrophilic state through modification. The results show that the mPEG-COOH-5 modified UCNPs present the highest stability in an aqueous solution. Fourier Transform Infrared Spectroscopy (FTIR) measurements reveal the presence of a significant number of -COOH functional groups on UCNPs after the mPEG-COOH-5 modification. These -COOH groups enhance the hydrophilicity and biocompatibility of UCNPs. The soluble UCNPs were directly mixed with microalgae, and the upconversion luminescence (UCL) spectra of the UCNPs were recorded immediately after thorough shaking. This greatly reduces the measurement time and could realize rapid onboard detection. In this sensing procedure, the UCNPs with red UCL functioned as energy donors, while microalgae with red absorption served as an energy acceptor. The UCL gradually diminishes with an increase in microalgae concentration based on the inner filter effect, thus establishing a relationship between UCL and microalgae concentration. The accuracy of the detection is further validated through the traditional microscope counting method. These findings pave the way for a novel rapid strategy to assess microalgae concentration using UCNPs.

‘Challenges and Regulatory Precautionary Approach of Flag States in Implementing Obligations Under the Ballast Water Management Convention’

Increasing shipping activities necessitated by an upsurge in international trading has a resultant impact on the marine ecosystem. Apart from the usual incidences of marine pollution and oil spillages, the introduction and transfer of invasive alien species (IAS), often known as harmful aquatic organisms and pathogens (HAOP), are increasing and impacting marine ecosystems and biological diversities. In realization of these threats, at the United Nations Conference on Environment and Development (UNCED), the International Maritime Organization (IMO) was requested to consider the adoption of appropriate rules on ballast water discharge based on the understanding that ships’ ballast water serves as a pathway for such bio-invasion transfer. Responding to these challenges led to the adopting of several regulations, technical guidelines, and rules, including the Ballast Water Management Convention in 2004. Hence, implementing the Convention has several implications for the existing legal regimes on flag states. The Convention and its Guidelines are complex and technical, coupled with a differential approach to ballast water management (BWM) by non-state parties like the U.S. Therefore, this research paper analyses some of the challenges and precautionary regulatory approaches for flag states in implementing the Convention while carrying out their obligations under the Convention. It concluded by suggesting a reflection of universally acceptable and environmentally friendly standards for ballast water management and treatment for containing the increasing prevalence of bio-invasion in the marine ecosystem.

Design proposal for a ballast treatment system to reduce the invasion of species in the Galapagos

Ballast water is necessary to maintain the stability of the vessels when loading and unloading their merchandise. However, it is also one of the main causes of species invasions in many ports around the world. The Galapagos Islands are no exception to this problem, since according to investigations several non-native species have been found due to ballast transport. Therefore, this project focused on the development of an alternative model for a ballast water treatment system using the chemical method to prevent the invasion of species in the Islands. As a result, two models were obtained. In the first, one NaClO dosing pump is used and in the second, two pumps are used. Each one of them was carried out from the Isla de la Plata ballast system and using RhinoCeros and AutoCAD software. In conclusion, after the modeling of both proposals and the technical analysis of the current ballast system of the vessel, it was determined that they comply with the provisions of the IMO and that they are the basis for the subsequent implementation of the alternatives.

Examining the effectiveness of oiled ballast water treatment processes: Insights into hydrocarbon oxidation product formation and environmental implications

Ballast water released from ships into coastal environments has been identified as a mechanism that introduces contaminants of concern into coastal ecosystems. This study investigates the treatment processes employed at...

CAREER PROFILES • OPTIONS AND INSIGHTS: Scott Loranger

I received a Bachelor of Science in biological sciences with a focus on ecology and evolutionary biology from Cornell University in 2009. I also spent a semester with SEA Education Association out of Woods Hole, Massachusetts, and that experience solidified my interest in oceanography. As I delved deeper into marine science, I became interested in ecological resilience and response to change. Following my undergraduate education, I worked with a group at the University of Maryland Center for Environmental Science – Chesapeake Biological Labora­tory studying technology to treat ballast water to deter transport of invasive species, and technology to measure oil concentrations in the ocean to respond to oil spills. This was my first foray into applied science and emerging technologies. My interest in technology and oil spill response led me to the University of New Hampshire (UNH) and the Center for Coastal and Ocean Mapping, where I obtained a PhD in oceanography, graduating in 2019. At UNH, I studied the use of broadband acoustic echo sounders to map, characterize, and quantify oil spills. For my thesis, I studied the 2004 Taylor Energy oil spill in the Gulf of Mexico, the longest-running oil spill in US history.

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.

Development of UV reactor controller in ballast water treatment system to minimize the biological threat on marine environment

Ballast water management is an effective measure to ensure that organisms and bacteria do not migrate with the ballast water to other areas. The International Maritime Organization adopted the International Convention on the Control and Management of Ballast Water and Ship Sediments, in 2004 which regulates issues of ballast water management. Many technologies have been researched and developed; in particular, using UV rays is the method that is evaluated with many advantages and meets the requirements of the Convention. The UV reactor in the ballast water treatment system has a very large capacity, so in the ballast water treatment system, it is often necessary to use many high-power UV lamps in one UV reactor. These high-power UV lamps consume a lot of electrical energy and are very expensive. Research on the control of UV radiation in the process of disinfecting water appropriately and effectively is necessary in order to improve the life of UV lamps, consume less electricity, and ensuring anti-bacterial duty is well conducted. This paper presents the development of a controller for a UV reactor and ballast water flow in the ballast water treatment system installed on ships. Experimental results on ships indicate the efficiency achieved by the developed UV controller.

Study on Ship Ballast Water Treatment Methods

With the rise of the world's maritime industry, the ecological and environmental concerns produced by ballast water discharges from ships are growing more and more significant, and can be hazardous to marine ecosystems, the marine economy, and human health. The ballast water management (BWM) convention from the International Maritime Organization (IMO) sets the rules for ballast water discharge and the two methods of ballast water exchange and ballast water treatment. Common types of ballast water management technology are introduced in this paper and the pros and cons of specific types of technology are explained. The research of this paper demonstrates that it is difficult for a single ballast water treatment system to achieve the D-2 discharge standard established in the BWM. More and more countries are increasingly supporting more efficient and environmentally friendly ballast water combination treatment systems. This paper may offer a reference for the development of ballast water treatment technology.