Ballast Tanks Research Articles

Impact of air, water and dock microbial communities on boat microbial community composition.

This study explores the microbial diversity of sources which may influence boat microbial communities. We investigated the impact of dock, air and water microbial communities on the hull, transom and bilge microbial communities over the span of 11days. Using source tracking software, we investigated the extent to which each of our potential sources (air, water and dock) influenced the overall microbial community. This study concluded that the dock impacted 14-64% of the hull and transom microbial community. Micro-organisms from the water were shown to impact 5·6% the bilge microbial community but had minimal impact on hull and transom microbial communities. Micro-organisms from the air had minimal impact in all areas of the boat. Our results demonstrate that micro-organisms from sources other than water can influence the microbial community of a boat, suggesting that terrestrial micro-organisms can impact the boat microbial community. Outside of ballast tanks, microbial diversity on boats is largely unexplored. While ballast water is widely recognized as a route for dispersal of allochthonous micro-organisms, comparatively little is known about the microbial diversity on other areas of the boat. If the organisms on a boat originate from sources other than water, there is potential that terrestrial micro-organisms could be dispersed by shipping activity.

PRELIMINARY INVESTIGATION OF THE CHEMICAL COMPOSITION OF BALLAST WATER AND TANK SEDIMENTS OF SELECTED SHIPS WITHIN THE LAGOS HARBOUR, NIGERIA

Ballast water is important for safe and efficient operation of vessels, helping to maintain stability during voyage in seas and docking in harbours. However, ballast water can pose considerable environmental challenges because they are often laden with polluted sediments and invasive species. The Lagos Harbour, which houses in the largest port in West Africa, receives about five thousand vessels annually which discharge ballast water and tank sediments into the water with the potential to cause environmental pollution. In the Nigerian context there is high potential for pollution due to weak regulations, poor enforcement and limited research of this kind in order to understand their composition, fate and impacts. This study aims at characterizing the chemical composition (Heavy metals- Arsenic, Cadmium, Chromium, Copper, Lead & Zinc, as well as carbon and nitrogen content) of the ballast water and the tank sediments because of their positive correlation with the survival of invasive species in the ballast water and tank sediments. Water samples were collected from four ships (2 cargos and 2 tankers) within the Lagos Harbour; surface (1-5 cm) sediment samples were scooped from ship tanks using a specialized grab for sampling ballast sediments. The sediments were transferred in specialized sample containers (cool boxes) to the University of Portsmouth in United Kingdom for analysis. Total metal concentrations were analysed using X-ray fluorescence (XRF). They were subjected to two acid digestions: Aqua regia (AR) and 1 M hydrochloric acid (1 M HCl) following the procedures set out by the Canadian National Water Research Institute (NWRI) and the United States Environment Protection Agency (US-EPA Method 3050B). Total carbon and nitrogen contents were determined using an in-line Yanaco MT-5 CHN analyser. The results obtained were compared with established guidelines and subjected to correlation and Principal Component Analysis (PCA). The findings indicated high concentrations of Nickel, Lead, and Zinc in the sediments with values of 59.6 mg/kg, 33.75 mg/kg and 43,145.7 mg/kg respectively which exceeded NOAA and CSQGs permissible standards. Tanker vessels contained relatively higher concentrations of the pollutants than cargo vessels. The findings from this study provide useful baseline data which will guide a more intensive investigation of the chemical composition of ballast water and tank sediments for effective comparison with what is obtainable elsewhere in the world. The maritime industry needs to pay close attention to ballast as a potential source of marine pollution particularly in developing countries like Nigeria where there is limited regulation for management of coastal areas with respect to shipping activities. The IMO needs to direct further effort at investigating the non-biological components of ballast water and sediments in order to protect valuable biodiversity. Keywords: Coastal Pollution, Ballast Water Management, Ships, Analytical Techniques

Comparative analysis of energy efficiency of ballast tank anti-freezing systems

Choosing the best way to deal with the internal icing of ballast tanks is the important task of the designing Arctic vessels. To prevent excessive ice formation in the ballast tank, various methods are used, the main of which are: heating the water and increasing of the water circulation intensity inside the tank (air and steam bubbling, forced water circulation). The report presents qualitative assessment of the heating method and air bubbling system and investigation of energy efficiency of anti-freezing systems.

Application of the environmentally safe operating schemes to the cooling systems of ship power plant

The possibility of using the ecologically safe operation on a closed-loop circuit instead of an open-loop cooling system is considered. For this purpose, it was proposed to use the ballast tanks on the ship. To ensure effective heat removal, it is proposed to apply a jet inlet of coolant to the hull shell of a ship. The flow regimes of the impact fluid jet were visualized. The critical Reynolds number is determined. Heat transfer coefficients and generalizing calculation dependences are determined by experiments.

Development and Experiments of an Electrothermal Driven Deep-Sea Buoyancy Control Module.

Due to the extremely high pressures in the deep sea, heavy ballast tanks and pressure compensating hydraulic tanks are typically required to support the operation of classic buoyancy controls. Buoyancy control systems driven by phase-change materials (PCM) have unique advantages over conventional hydraulically actuated buoyancy control systems, including high adaptability for deep-sea exploration and simple, lightweight, and compact structures. Inspired by this, a buoyancy control module (BCM) was designed with flexible material as the shell. Instead of a conventional mechanical system, the device uses an electric heating drive to control buoyancy by heating and cooling the PCM. Based on the principle of pressure compensation, this device can adjust the buoyancy of a small underwater vehicle in a deep-sea high-pressure environment. The BCM successfully adjusts the buoyancy to lift itself up and down in the South China Sea at a depth of 3223 m. The performance of the phase-change BCM to control buoyancy under high pressure is validated by systematic experiments and theoretical analysis. Our work proposes a flexible scheme for the design of a deep-sea phase-change-driven BCM and highlights its potential application in deep-sea micro-mechanical systems, especially soft robots.

Summer bloom of Vulcanodinium rugosum in Cienfuegos Bay (Cuba) associated to dermatitis in swimmers

The marine dinoflagellate Vulcanodinium rugosum produces powerful paralyzing and cytotoxic compounds named pinnatoxins (PnTX) and portimines. Even though, no related human intoxication episodes following direct exposure in seawater or the ingestion of contaminated seafood have been documented so far. This study aimed at investigating a dinoflagellate bloom linked to acute dermatitis cases in two recreational beaches in Cienfuegos Bay, Cuba. We used epidemiological and clinical data from 60 dermatitis cases consisting of individuals in close contact with the bloom. Seawater physical-chemical properties were described, and the microorganism causing the bloom was identified by means of light and scanning electron microscopy. Morphological identification was confirmed genetically by sequencing the internal transcribed spacers ITS1 and ITS2, and the 5.8S rDNA region. Toxic compounds were identified from a bloom extract using liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS), and their concentrations were estimated based on low-resolution tandem mass spectrometry (LC-MS/MS). Sixty people who had prolonged contact with the dinoflagellate bloom suffered acute dermal irritation. Most patients (79.2%) were children and had to be treated with antibiotics; some required >5-day hospitalization. Combined morphological and genetic characters indicated V. rugosum as the causative agent of the bloom. rDNA sequences of the V. rugosum genotype found in the bloom aligned with others from Asia, including material found in the ballast tank of a ship in Florida. The predominant toxins in the bloom were portimine, PnTX-F and PnTX-E, similar to strains originating from the Pacific Ocean. This bloom was associated with unusual weather conditions such as frequent and prolonged droughts. Our findings indicate a close link between the V. rugosum bloom and a dermatitis outbreak among swimmers in Cienfuegos Bay. Phylogenetic evidence suggests a recent introduction of V. rugosum from the Pacific Ocean into Caribbean waters, possibly via ballast water.

Wave-induced loads on a lock gate provided with an opening through the ballast tank

The wave loads on a navigation lock gate provided with an opening in the ballast tank are analyzed using a mathematical model based on the linear wave theory. The analysis focuses on the influence of the wave number and the geometrical characteristics of the structure on the applied load. It is shown that the maximum value of the vertical force mainly depends on the height of the ballast tank and on the width of the opening. The wave number for which the maximum load occurs significantly depends on the geometric characteristics of the structure except for the water depth above the ballast tank which has a negligible effect. An increase in the height of the ballast tank causes an increase in the wave load while an increase in the width of the opening causes a decrease in the wave load. Based on the results of the mathematical model an easy to use regression model has been developed which can be employed to evaluate the wave load.

Ballast Water Treatment Performance Evaluation under Real Changing Conditions

We conducted a shipboard ballast water test using seawater of extreme turbidity collected from Shanghai Port (China) (>300 mg total suspended solids (TSS)/L), and normal seawater collected in other ports (<100 mg TSS/L). All three types of International Maritime Organization (IMO)-approved ballast water management system (BWMS) tested failed to properly operate because of filter clogging or insufficient generation of oxidants under near-fresh water conditions with extremely high concentration of suspended solid during ballasting. It was also found that the number of microorganisms increased with longer ballast water retention time, with higher numbers in the treated discharge water. The results suggest that when operating a BWMS involving a filter unit in areas with water having high concentrations of suspended solids, the filter unit should be used during ballast water discharge, rather than during ballasting. This method has the advantage of removing ≥50 µm organisms at discharge that could not be removed by a filter during ballasting. For ballast water retained for long storage times, the results suggest the use of BWMSs involving UV units or electrolysis during deballasting. In addition, BWMSs involving electrolysis units provide the opportunity to maintain residual total residual oxidant (TRO) levels, using a partial ballast tank. Although the BWMSs tested are a small subset of the large number of IMO-approved BWMSs, the results demonstrate that there is a significant gap between the technology currently available and capacity to meet IMO and US Coast Guard standards.

Analysis of Operating Principles and Flow Field Characteristics for a Diving Ballast Tank

Operating principle and flow field characteristics of a diving ballast tank for application in submerged vehicles were investigated in the present study. As understanding the complex changes in the interior air-water two-phase flow field of the ballast tank during the diving process is difficult, this study specifically performed a ballast tank diving experiment. Experimental and numerical simulations to analyse the diving motions of the ballast tank were conducted. Authors comprehensively evaluated the flow field changes in the ballast tank and its surroundings. The experimental and numerical results were compared in terms of the observed displacements and velocities during diving. Both the results indicated similar motion trajectories and velocities. Authors effectively observed the air-water two-phase flow field change inside the ballast tank using this numerical method. Therefore, the numerical model constructed in this study can be useful for analysing the diving motions of ballast tanks and can effectively predict the interior flow field characteristics of a ballast tank.

A Study into the Coating Thickness of Ship Ballast Tanks

Ballast tanks are expected to be coated according to the IMO Performance Standard for Protective Coating regulations (PSPC15), in addition to the paint application requirements of the paint producer. In general, a coating system should consist of minimum two spray coats of light-colored epoxy coating on flat surfaces with a Nominal total Dry Film Thickness (NDFT) of 320 μm and 90% of all thickness measurements greater than, or equal to the NDFT and none of the remaining measurements below 0.9 x NDFT (the “90/10 rule”). Allegedly, the value of 320 μm in this PSPC15 rule may be misconstrued as a benchmark for coating application on flat surfaces, eventually leading to a non-PSPC15 compliance due to the resulting variation in coating thickness violating this 90/10 rule. This study indicates that over the years, the arithmetic mean in-situ DFT appears to be 498±18 μm and that too high and low thicknesses, below 288 μm and above 800 μm, were noted in the field. Analysis of a survey of ballast tank coating performance of ships indicates that too low thicknesses appear to be negatively impacting the average theoretical ballast tank performance. However, when an application mean DFT benchmark of 525 μm is used, the coating will almost surely comply to the 90/10 rule and the risk of falling below the 288 μm threshold is small, less than 2% in most cases. Consequently, using 320 μm as a mean DFT benchmark could result in a non-PSPC15 compliance with the in-situ ascertained coating thickness variation as this does not exclude coating thicknesses below 288 μm, which may then result in a significantly less than average theoretical coating performance. If the coating application is performed very evenly, the benchmark may be reduced to 429 μm with a probability of falling below 288 μm reduced to 0.1%. It should therefore be emphasized that the PSPC15 requirement is a coating system framework description, and that the requirement should be broadened to include a mean DFT as a coating applicator benchmark together with a clearly specified minimum and maximum DFT, in order to avoid any misinterpretations.

Simulating Flood Recovery Manoeuvres Using a Free-Running Submarine Model

Managing submarine safety, effectively, requires an understanding of many areas of platform performance, including its ability to manoeuvre. QinetiQ’s free-running submarine model (FRM) capability, the second generation Submarine Research Model (SRMII), forms a key part of the UK’s predictive manoeuvring capability that supports the MoD’s ability to conduct hydrodynamic assessment of the manoeuvring and control performance of the Royal Navy’s current and future submarines. Uniquely for an FRM, the SRMII has a large and capable ballast system. This is able to emulate a flooding incident within a submarine compartment and the subsequent emergency recovery procedures, which may include blowing the submarine’s main ballast tanks. This paper discusses how the SRMII’s ballast system was used to generate model-scale trajectories, which are not obtainable with many other FRMs. The experimental data were used to successfully validate the mathematical model, which predicts the maximum pitch angle response of a full-scale submarine to a compartment flood, to within an average accuracy of 1% at model-scale. However, the range of the non-dimensional flow angles the FRM exhibited was shown to be within that for a full-scale flood trajectory. Therefore, further tests have been proposed to increase the extent of the data in the future.

Simulation of emergency hovering maneuvers in submarines

Submarines are one of the most advanced marine vehicles navigating from the surface of the water to the depths of the seas and able to perform various operations. Submarines have no benefit in terms of speed relative to surface floats, but also the advantage of a (moving underwater) dive deep into the deep seas. Diving and hovering of a submarine are carried out with the help of water ballast tanks (WBTs). Considering the importance of WBTs in the dynamic and static stability of the submarine, in examining the emergency maneuver operations using WBTs, complete modeling of the compressed air blowing process in the main WBTs of a submarine should be made. Blowing and unloading submarine ballasts can potentially use as a complementary control system to improve submarine maneuverability. Submarine ballast tanks can use as a tool for emergency hovering operation. This critical issue has simulated in this article using StarCCM + software, among which the governing equations and essential parameters have been investigated. Also, a sensitivity analysis was done on the results.

Sloshing effect, Fluid Structure Interaction analysis

The sloshing effect of the liquids is considered to be an important factor in area such as cargo ships (tankers) which transporting petroleum liquids or other liquids (water inside of ballast tanks). Sloshing can produce big problems so is essential to apply the prevention measures. For example in water ballast tanks, the sloshing motion of sea water inside of ballast tanks will bring large fluid pressures and impact loads, which might destroy the structure of tanks. It is known that ships with larger tanks, less internal structure, and more free surface area, the number of failures attributed to sloshing liquids have increased. Nowadays it is recognized that the ballast tanks which may be partly filled are the crucial group of tanks onboard. The problem of an assessment of liquid sloshing effect is more important than ever because of the obligatory ballast water management requirement. Our paper is an original fluid structure interaction analysis during sloshing phenomenon. We are using ANSYS CFX to simulate the behavior of two fluids, (seawater and air from the ballast tank), requires itself the multiphase flow model. Due to the movement of the ballast/cargo tanks is complex involving pitching and rolling of ship, it is clear that the simulation is done with the ANSYS CFX transient module. Because this complex simulation requires massive resources calculation we consider a simplified CAD models for a part of the oil chemical ballast tank structure.

A hybrid risk prioritization method based on generalized TODIM and BWM for Fine-Kinney under interval type-2 fuzzy environment

The risk prioritization process is one of the most crucial steps for risk evaluation of potential hazards. The Fine-Kinney method has been commonly applied to controll risks in practice, while the classical Fine-Kinney has limitations in the determination of important degrees of risk parameters. In addition, current risk prioritization approaches for Fine-Kinney overlook the bounded rational behavior of expert within the uncertain context, especially, the high uncertain environment. The purpose of this paper is to develop a hybrid risk prioritization approach for Fine-Kinney by using generalized TODIM (an acronym in Portuguese of interactive and multi-criteria decision making), best-worst, and the interval type-2 fuzzy set. First, the linguistic terms and interval type-2 fuzzy numbers are adopted to handle the expression problem of the team members’ uncertain evaluation information. Second, in order to obtain the objective weights of risk parameters, the best-worst method is proposed to determine the relative importance degrees of risk parameters. Third, the interval type-2 fuzzy numbers are incorporated into the generalized TODIM method to determine the risk priority orders of hazards, which can simulate the experts’ bounded rational behavior under uncertain environment. Finally, a practical risk analysis example of ballast tank maintenance and the sensitivity and comparison analysis is presented to demonstrate the application of the proposed Fine-Kinney framework. The sensitivity analysis and comparison are employed to validate the reliability of the new risk prioritization model.

Survey of Marine Phytoplankton in Ship’s Ballast Tanks at Laem Chabang International Port, Thailand

Marine phytoplankton was investigated in ballast water of ships from 2010 to 2012 with a collection of 30 marine vessels that docked at Laem Chabang International Port in Chonburi Province, Thailand. The results showed that the dominant group of phytoplankton was diatoms. The amount of phytoplankton in the ballast tanks averaged less than 10 cells/ mL, which is less than Regulation D-2 of the Ballast Water Management Convention which requires that marine organisms between the sizes of 10 ? X <50 µm should be less than 10 cells/mL and size ? 50 µm should be less than 10 cell/m3 in ballast water. Alien species of phytoplankton was not recorded in this survey.

Improving the energy efficiency of ship tank heating systems

One of the challenges for creating objects of marine equipment operating in arctic conditions is to prevent freezing of fluids in tanks at extremely low temperatures as it may cause damage to the ship and its systems. This problem can be solved with efficient heating systems for ship tanks. In the paper the ballast tank heating simulation and optimization of heating coil position is discussed. The considered heating coil is typical for icebreakers and ice-class vessels (Arc 5 and above). On the basis of the performed computations the recommendations for improving the energy efficiency of ship heating systems are formulated.

Effects on inactivation of Tetraselmis suecica following treatment by KBAL: a UV-based ballast water treatment system with an in-line vacuum drop

The transfer of non-native, possibly invasive species in ship’s ballast water is of global concern, and the International Maritime Organization and U.S. Coast Guard have adopted standards to minimize the environmental footprint caused by the maritime industry. In this study, seawater spiked with the phytoplankter Tetraselmis suecica, was treated with Knutsen Ballast Water Treatment Technology (KBAL), combining UV irradiation with an in-line vacuum drop. The test water was subsequently incubated in dark tanks, simulating what happens onboard a ship, where ballast water is treated at intake, stored in dark ballast tanks during the voyage, and then treated at discharge. Our results of the test water treated with KBAL and stored 5 days in the dark showed < 10 viable T. suecica cells ml−1 when assessing reproduction and > 10 living cells ml−1 when assessing metabolism. This highlights the challenge UV-based BWTS can encounter when meeting testing regimes assessing different characteristics of life. By comparing the effects caused by KBAL treatment with effects caused by UV irradiation only, we demonstrated that the pressure/vacuum technology seems to improve the disinfection effect. In addition, our investigations point out possible challenges with in situ conditions getting representative ballast water samples.

Historical human activities reshape evolutionary trajectories across both native and introduced ranges.

The same vectors that introduce species to new ranges could move them among native populations, but how human‐mediated dispersal impacts native ranges has been difficult to address because human‐mediated dispersal and natural dispersal can simultaneously shape patterns of gene flow. Here, we disentangle human‐mediated dispersal from natural dispersal by exploiting a system where the primary vector was once extensive but has since ceased. From 10th to 19th Centuries, ships in the North Atlantic exchanged sediments dredged from the intertidal for ballast, which ended when seawater ballast tanks were adopted. We investigate genetic patterns from RADseq‐derived SNPs in the amphipod Corophium volutator (n = 121; 4,870 SNPs) and the annelid Hediste diversicolor (n = 78; 3,820 SNPs), which were introduced from Europe to North America, have limited natural dispersal capabilities, are abundant in intertidal sediments, but not commonly found in modern water ballast tanks. We detect similar levels of genetic subdivision among introduced North American populations and among native European populations. Phylogenetic networks and clustering analyses reveal population structure between sites, a high degree of phylogenetic reticulation within ranges, and phylogenetic splits between European and North American populations. These patterns are inconsistent with phylogeographic structure expected to arise from natural dispersal alone, suggesting human activity eroded ancestral phylogeographic structure between native populations, but was insufficient to overcome divergent processes between naturalized populations and their sources. Our results suggest human activity may alter species' evolutionary trajectories on a broad geographic scale via regional homogenization and global diversification, in some cases precluding historical inference from genetic data.

Sediments in the ship’s ballast water tank: a problem to be solved

The International Maritime Organization’s (IMO) International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) was entered into force in September 2017. It deals with one of the greatest threats to coastal and marine environments around the world: aquatic invasive alien species (IAS) and harmful aquatic organisms and pathogens (HAOP). Although the control of IAS and HAOP through treatment of ballast water (BW) is appropriately dealt with in the Convention and its implementation, the problems generated by sediments are not treated in such a manner. There are many published technical and scientific papers, discussions and commentaries proposing the remediation of the present situation. They are discussed, and recommendations are summarized. Besides, several systems for the treatment of BW use a combination of two or three techniques, with filtration usually being the first and/or the last step. Presence of sediments in BW results in the reduced applicability of such an approach. The requirements for sediment management procedures are discussed along with a proposal for their implementation. In the first step, the ballast tank sediments should be freed of active biological agents for the elimination of IAS and HAOP. Instead of biological agents, we advocate the use of radiation treatment by using an electron accelerator, preferably in an on-shore installation or as a mobile, additive, sea container size units with integral power, separated for water and sediment treatment. In the second step, the concentrations of heavy metals should be determined. We recommend the use of EDXRF as an analytical method. After the determination of sediment class, the recommended disposal procedures should be followed. Sediment management procedures should specify the disposal requirements: (i) free of active biological agents, IAS and HAOP; (ii) chemical composition, no chemical elements in a toxic range (≤ Class 3); and (iii) displacement/storage requirements, displacing sediments characterized as harmful in appropriate sediment reception facilities/landfills.

Design and Analysis of a Variable Buoyancy System for Efficient Hovering Control of Underwater Vehicles with State Feedback Controller

The design process for Variable Buoyancy System (VBS) is not known in full, and existing approaches are not scalable. Furthermore, almost all the small size Autonomous Underwater Vehicles/Gliders (AUVs/G’s) use very low capacity of buoyancy change (in the range of few milliliters) and the large size AUVs require large buoyancy change. Especially for adverse weather conditions, emergency recovery or defense-related applications, higher rate of rising/sinking (heave velocity) is needed along with an ability to hover at certain depth of operation. Depth of UVs can be controlled either by changing the displaced volume or by changing the overall weight and, herein, our focus is on the later. This article presents the problem of design and analysis of VBS for efficient hovering control of underwater vehicles at desired depth using the state feedback controller. We formulate and analyze the design and analysis approach of VBS using the fundamental of mechanics, system dynamics integration and control theory. Buoyancy is controlled by changing the overall weight of the vehicle using the ballasting/de-ballasting of water in ballast tanks through the use of Positive Displacement Pump (PDP) for control in heave velocity and hovering depth. Furthermore, detailed mass metric analysis of scalable design of VBS for different buoyancy capacities is performed to analyze the overall performance of the VBS. Also, the performances of AUVs integrated with VBS of different buoyancy capacities are investigated in both the open loop and closed loop with the LQR state feedback controller. Hovering performance results are presented for three Design Examples (DEs) of AUVs with 2.8 m, 4.0 m and 5.0 m length and they are integrated with various buoyancy capacities at 9 kg/min rate of change of buoyancy. Results indicate that the AUVs achieve the desired depth with almost negligible steady state error and when they reach the desired hovering depth of 400 m the maximum pitch angle achieved of 16.5 degree for all the Des is observed. Maximum heave velocity achieved during sinking is 0.44 m/s and it reduces to zero when the vehicle reaches the desired depth of hovering. The presented computer simulation results indicate good performance and demonstrate that the designed VBS is effective and efficient in changing the buoyancy, controlling and maintaining the depth, controlling the heave velocity and can be used in rescue/attack operations of both the civil and defense UVs.