Ballast Water Treatment Research Articles

ANALYSIS INTO THE SELECTION OF A BALLAST WATER TREATMENT SYSTEM

Today, it is very important to select and install the optimal equipment for the treatment of ballast water in existing ships. Increasing cargo volumes demand for a greater number of ships for transportation and expanded navigation geography as well as result in increased amount of discharged ballast water. Consequently, sea water pollution is increasing and invasive microorganisms appear that the existing flora and fauna are unaccustomed to. In order to protect territorial waters from these invasive species, International Maritime Organization (IMO) requirements have been implemented that regulate the quality parameters of discharged ballast water from ships. This problem has become particularly relevant for operational ships, in which ballast water treatment equipment and technical solutions had not been anticipated in the design stage. This article provides a comparative analysis of the treatment equipment of ballast water and the related technical parameters, in order to distinguish the most important equipment criteria. A Carrier, according to its technical characteristics, was analysed together with the water treatment method for operated bulk. An expert evaluation for the characteristics of the technical equipment was established.

On the use of the serial dilution culture method to enumerate viable phytoplankton in natural communities of plankton subjected to ballast water treatment.

Discharge standards for ballast water treatment (BWT) systems are based on concentrations of living cells, for example, as determined with vital stains. Ultraviolet radiation (UV) stops the reproduction of microorganisms without killing them outright; they are living, but not viable, and ecologically as good as dead. Consequently, UV-treated discharge can be compliant with the intent of regulation while failing a live/dead test. An alternative evaluation of BWT can be proposed based on the assessment of viable, rather than living, cells in discharge water. In principle, the serial dilution culture-most probable number (SDC-MPN) method provides the appropriate measure for phytoplankton. But, the method has been criticized, particularly because it is thought that many phytoplankton species cannot be cultured. A review of the literature shows that although SDC-MPN has been used for more than 50 years—generally to identify and count phytoplankton species that cannot be preserved—its application to enumerate total viable phytoplankton seems to be new, putting past criticisms of the method in a different light. Importantly, viable cells need to grow only enough to be detected, not to be brought into sustained culture, and competition between species in a dilution tube is irrelevant as long as the winner is detectable. Thorough consideration of sources of error leads to recommendations for minimizing and quantifying uncertainties by optimizing growth conditions and conducting systematic comparisons. We conclude that with careful evaluation, SDC-MPN is potentially an effective method for assessing the viability of phytoplankton after BWT.

Sulphur emission control areas and transport strategies -the case of Sweden and the forest industry

Background and purposeThe International Maritime Organisation’s (IMO) decision to lower the allowable amount of sulphur content in marine fuels to 0.1 % in the so-called Emission Control Areas (ECAs) beginning in 2015 has outraged the Swedish forest industry. The seas around Sweden are included in the ECA and achieving the new sulphur directive requires shipowners to take actions that will increase the cost of transporting goods by ship from Sweden. Swedish forest industry exports are transported mostly by ship and there is a possibility that the forest industry will shift freight from sea to land transport because of the sulphur directive. How greatly the transport costs differ between different transportation options is affected by several uncertainties such as price trends for fuel. Other restrictions for shipping, such as nitrogen oxide emissions and ballast water treatment, are also expected to become stricter in the future. The purpose of this paper is to examine the impact of the sulphur directive and associated uncertainties on the Swedish forest industry, its transport system structure, and its logistics strategies.Results and conclusionsPrevious studies in the field have forecast that the freight will be transferred to land because of the sulphur directive. Our results also show that companies will transfer the cargo to land transport. The transfer will be greater the further south in the country production facilities are located. Goods that previously were shipped from ports on the Swedish east coast will instead be shipped more frequently from ports on the west coast to reduce transport time within the ECA region. Furthermore, the results show that firms do not sign agreements with shipping lines that extend beyond the year 2015, but instead write long, flexible agreements with rail operators, enabling an increase in freight strategy to address the sulphur directive. In this way, they have created the capacity to transform the transport structure.

Enhancing the efficacy of electrolytic chlorination for ballast water treatment by adding carbon dioxide

We examined the synergistic effects of CO2 injection on electro-chlorination in disinfection of plankton and bacteria in simulated ballast water. Chlorination was performed at dosages of 4 and 6ppm with and without CO2 injection on electro-chlorination. Testing was performed in both seawater and brackish water quality as defined by IMO G8 guidelines. CO2 injection notably decreased from the control the number of Artemia franciscana, a brine shrimp, surviving during a 5-day post-treatment incubation (1.8 and 2.3 log10 reduction in seawater and brackish water, respectively at 6ppm TRO+CO2) compared with water electro-chlorinated only (1.2 and 1.3 log10 reduction in seawater and brackish water, respectively at 6ppm TRO). The phytoplankton Tetraselmis suecica, was completely disinfected with no live cell found at >4ppm TRO with and without CO2 addition. The effects of CO2 addition on heterotrophic bacterial growth was not different from electro-chlorination only. Total residual oxidant concentration (TRO) more rapidly declined in electro-chlorination of both marine and brackish waters compared to chlorine+CO2 treated waters, with significantly higher amount of TRO being left in waters treated with the CO2 addition. Total concentration of trihalomethanes (THMs) and haloacetic acids (HAAs) measured at day 0 in brackish water test were found to be 2- to 3-fold higher in 6ppm TRO+CO2-treated water than in 6ppm TRO treated water. The addition of CO2 to electro-chlorination may improve the efficiency of this sterilizing treatment of ballast water, yet the increased production of some disinfection byproducts needs further study.

Transport of harmful marine microalgae via ship's ballast water: Management and mitigation with special reference to the Arabian Gulf region

The potential for transport of non-indigenous marine microalgae via ship's ballast water has been amply demonstrated, and nearly all known harmful algal bloom species have been documented in viable form from ship's ballast water. Ballast water uptake needs to be strongly discouraged during harmful algal bloom events. Efficacy of ballast water exchange in removing harmful microalgal cells is limited, since this nearly always leaves behind a viable inoculum. The precise location of ballast water exchange needs to be carefully chosen, and retention of dinoflagellate cysts and diatom spores in ballast tank sediments is of special concern. The only fully effective ballast water treatment for microalgae is the application of biocides, but heat treatment also offers considerable promise especially in subtropical and tropical waters. To manage harmful algal blooms, other key environmental drivers such as eutrophication and climate change also need to be addressed. Effective monitoring for harmful algal species and their toxins remains the critical tool to protect human health, fisheries, aquaculture and desalination industries. Challenges and opportunities for ballast water management in the Arabian Gulf region are discussed.

A comparison of six different ballast water treatment systems based on UV radiation, electrochlorination and chlorine dioxide

The spread of aquatic invasive species through ballast water is a major ecological and economical threat. Because of this, the International Maritime Organization (IMO) set limits to the concentrations of organisms allowed in ballast water. To meet these limits, ballast water treatment systems (BWTSs) were developed. The main techniques used for ballast water treatment are ultraviolet (UV) radiation and electrochlorination (EC). In this study, phytoplankton regrowth after treatment was followed for six BWTSs. Natural plankton communities were treated and incubated for 20 days. Growth, photosystem II efficiency and species composition were followed. The three UV systems all showed similar patterns of decrease in phytoplankton concentrations followed by regrowth. The two EC and the chlorine dioxide systems showed comparable results. However, UV- and chlorine-based treatment systems showed significantly different responses. Overall, all BWTSs reduced phytoplankton concentrations to below the IMO limits, which represents a reduced risk of aquatic invasions through ballast water.

Relative invasion risk for plankton across marine and freshwater systems: examining efficacy of proposed international ballast water discharge standards.

Understanding the implications of different management strategies is necessary to identify best conservation trajectories for ecosystems exposed to anthropogenic stressors. For example, science-based risk assessments at large scales are needed to understand efficacy of different vector management approaches aimed at preventing biological invasions associated with commercial shipping. We conducted a landscape-scale analysis to examine the relative invasion risk of ballast water discharges among different shipping pathways (e.g., Transoceanic, Coastal or Domestic), ecosystems (e.g., freshwater, brackish and marine), and timescales (annual and per discharge event) under current and future management regimes. The arrival and survival potential of nonindigenous species (NIS) was estimated based on directional shipping networks and their associated propagule pressure, environmental similarity between donor-recipient ecosystems (based on salinity and temperature), and effects of current and future management strategies (i.e., ballast water exchange and treatment to meet proposed international biological discharge standards). Our findings show that current requirements for ballast water exchange effectively reduce invasion risk to freshwater ecosystems but are less protective of marine ecosystems because of greater environmental mismatch between source (oceanic) and recipient (freshwater) ecoregions. Future requirements for ballast water treatment are expected to reduce risk of zooplankton NIS introductions across ecosystem types but are expected to be less effective in reducing risk of phytoplankton NIS. This large-scale risk assessment across heterogeneous ecosystems represents a major step towards understanding the likelihood of invasion in relation to shipping networks, the relative efficacy of different invasion management regimes and seizing opportunities to reduce the ecological and economic implications of biological invasions.

Efficacy of pH elevation as a bactericidal strategy for treating ballast water of freight carriers

Treatment of ship ballast water with sodium hydroxide (NaOH) is one method currently being developed to minimize the risk to introduce aquatic invasive species. The bactericidal capability of sodium hydroxide was determined for 148 bacterial strains from ballast water collected in 2009 and 2010 from the M/V Indiana Harbor, a bulk-freight carrier plying the Laurentian Great Lakes, USA. Primary culture of bacteria was done using brain heart infusion agar and a developmental medium. Strains were characterized based on PCR amplification and sequencing of a portion of the 16S rRNA gene. Sequence similarities (99+ %) were determined by comparison with the National Center for Biotechnology Information (NCBI) GenBank catalog. Flavobacterium spp. were the most prevalent bacteria characterized in 2009, comprising 51.1% (24/47) of the total, and Pseudomonas spp. (62/101; 61.4%) and Brevundimonas spp. (22/101; 21.8%) were the predominate bacteria recovered in 2010; together, comprising 83.2% (84/101) of the total. Testing was done in tryptic soy broth (TSB) medium adjusted with 5N NaOH. Growth of each strain was evaluated at pH 10.0, pH 11.0 and pH 12.0, and 4h up to 72h. The median cell count at 0h for 148 cultures was 5.20×106cfu/mL with a range 1.02×105–1.60×108cfu/mL. The TSB adjusted to pH 10.0 and incubation for less than 24h was bactericidal to 52 (35.1%) strains. Growth in pH 11.0 TSB for less than 4h was bactericidal to 131 (88.5%) strains and pH 11.0 within 12h was bactericidal to 141 (95.3%). One strain, Bacillus horikoshii, survived the harshest treatment, pH 12.0 for 72h.

Hybrid system increases efficiency of ballast water treatment

Summary Ballast water has been a principal pathway of non‐indigenous species introduction to global ports for much of the 20th century. In an effort to reduce the scale of this pathway, and recognizing forthcoming global regulations that will supplant ballast water exchange (BWE) with ballast water treatment (BWT), we explore whether a combined hybrid treatment of BWE and chlorination (Cl) exceeds individual effects of either BWE or chlorination alone in reducing densities of bacteria, microplankton and macroplankton. Five full‐scale trials were conducted on an operational bulk carrier travelling between Canada and Brazil. The hybrid treatment generally had the lowest final densities among all treatments for putative enterococci, Escherichia coli and coliform bacteria, as well as microplankton and macroplankton, with the former two being synergistically lower than individual treatments alone. Microplankton abundance in the hybrid treatment was significantly but antagonistically reduced relative to individual treatments alone. Macroplankton final density was lowest in the hybrid treatment, though the interaction between treatments was not significant. Synthesis and applications. In most cases, the combined hybrid treatment of ballast water exchange (BWE) and chlorination reduced population densities of indicator organisms in ballast water below those proposed by the International Maritime Organization's D‐2 performance standards. BWE alone was often ineffective at reducing bacterial and macroplankton densities. Even when performance standards are implemented globally, continued use of BWE could further reduce risk of invasions to freshwater ecosystems that receive ballast water from foreign sources by accentuating the decline in propagule pressure and enhancing demographic constraints for putative invaders.

신개념 기계식 선박평형수 처리장치의 디스크 형상에 따른 유동특성에 관한 수치해석 연구

신개념 기계식 선박평형수 처리장치의 디스크 형상에 따른 유동특성에 관한 수치해석 연구

Peracetic acid oxidation of saline waters in the absence and presence of H ₂O ₂: secondary oxidant and disinfection byproduct formation.

Peracetic acid (PAA) is a disinfectant considered for use in ballast water treatment, but its chemical behavior in such systems (i.e., saline waters) is largely unknown. In this study, the reactivity of PAA with halide ions (chloride and bromide) to form secondary oxidants (HOCl, HOBr) was investigated. For the PAA-chloride and PAA-bromide reactions, second-order rate constants of (1.47 ± 0.58) × 10(-5) and 0.24 ± 0.02 M(-1) s(-1) were determined for the formation of HOCl or HOBr, respectively. Hydrogen peroxide (H2O2), which is always present in PAA solutions, reduced HOCl or HOBr to chloride or bromide, respectively. As a consequence, in PAA-treated solutions with [H2O2] > [PAA], the HOBr (HOCl) steady-state concentrations were low with a limited formation of brominated (chlorinated) disinfection byproducts (DBPs). HOI (formed from the PAA-iodide reaction) affected this process because it can react with H2O2 back to iodide. H2O2 is thus consumed in a catalytic cycle and leads to less efficient HOBr scavenging at even low iodide concentrations (<1 μM). In PAA-treated solutions with [H2O2] < [PAA] and high bromide levels, mostly brominated DBPs are formed. In synthetic water, bromate was formed from the oxidation of bromide. In natural brackish waters, bromoform (CHBr3), bromoacetic acid (MBAA), dibromoacetic acid (DBAA), and tribromoacetic acid (TBAA) formed at up to 260, 106, 230, and 89 μg/L, respectively for doses of 2 mM (ca. 150 mg/L) PAA and [H2O2] < [PAA]. The same brackish waters, treated with PAA with [H2O2] ≫ [PAA], similar to conditions found in commercial PAA solutions, resulted in no trihalomethanes and only low haloacetic acid concentrations.

Failure of the public health testing program for ballast water treatment systems

Since 2004, an international testing program has certified 53 shipboard treatment systems as meeting ballast water discharge standards, including limits on certain microbes to prevent the spread of human pathogens. We determined how frequently certification tests failed a minimum requirement for a meaningful evaluation, that the concentration of microbes in the untreated (control) discharge must exceed the regulatory limit for treated discharges. In 95% of cases where the result was accepted as evidence that the treatment system reduced microbes to below the regulatory limit, the discharge met the limit even without treatment. This shows that the certification program for ballast water treatment systems is dysfunctional in protecting human health. In nearly all cases, the treatment systems would have equally well “passed” these tests even if they had never been turned on. Protocols must require minimum concentrations of targeted microbes in test waters, reflecting the upper range of concentrations in waters where ships operate.

Development and testing of a rapid, sensitive ATP assay to detect living organisms in ballast water

To reduce the spread of aquatic invasive species, the discharge of ballast water by ships will soon be compulsorily regulated by the International Maritime Organization (IMO) and the United States Coast Guard (USCG). Compliance with their regulations will have to be achieved by onboard ballast water management systems. To monitor the treatment system performance, rapid and easy compliance techniques are required. This paper reports on the suitability of adenosine triphosphate (ATP) to quantify living 10–50-μm organisms at <10 cells mL−1, which is the upper limit of the IMO D-2 and USCG regulations. Initial tests revealed that commercially available ATP assays lacked sufficient sensitivity to monitor ATP in treated ballast water. A rapid and easy concentration method was developed to increase sensitivity and remove interfering salts, non-target organisms (Micromonas pusilla), and dissolved ATP. Laboratory experiments revealed that salinity was reduced 33 times and concentration efficiencies reached 85 %. The ATP assay was tested in a UV-based full-scale ballast water management system, treating seawater and fresh water. ATP levels were compared with two alternative compliance tools: fluorescein diacetate (FDA) and Photosystem II efficiency. Results showed a 10-fold decrease in ATP levels after treatment compared to a 5-fold decrease in alternative compliance techniques. Following refinements, the ATP assay’s detection limit reached 2.5 ± 0.5 cells mL−1 using a Thalassiosira rotula monoculture. Initial estimates of the pass and fail level were 50 and 6000 relative luminescence units, respectively. Further validation is recommended. The ATP assay is a promising tool for ballast water compliance testing.

Alternative, indirect measures of ballast water treatment efficacy during a shipboard trial: a case study

A shipboard study was conducted aboard the cruise ship Coral Princess during a scheduled cruise from San Pedro, CA, USA to Vancouver, British Columbia, Canada. The investigation involved three members of the global TestNet group, with experience in certification testing of ballast water treatment systems (BWTS) designed to eliminate entrained invasive species. A UV-based ballast water treatment system had been employed aboard the vessel for more than 10 years. A variety of established and experimental assessment techniques were employed, both aboard the ship and following shipment of samples via road (5 days) and air (7 days) to remote laboratories. The study was designed to compare the performance of different techniques in assessing BWTS compliance with international regulations, and to test the feasibility of compliance assessment by Port State Control internationally using different laboratories. Overall, biological end-points showed effective treatment of ballast water as judged by the percentage removal (mortality) of organisms in treated samples. Sample transport indicated generally good potential for ‘off-site’ sample analysis and displayed a possible latent effect of treatment as judged by a decline in photosynthetic yield associated with delayed analysis.

Formation of disinfection by-products during ballast water treatment with ozone, chlorine, and peracetic acid: influence of water quality parameters

Differences in water quality from freshwater to seawater alter disinfection by-product formation during disinfection of ballast waters.

The Effect of Rise Angle of V-Hull Non Ballast Ship on Seakeeping Performance

In this paper a new concept in ship design was used to be alternative of ballast water system, to emerge that remedy the introduction of invasive marine species and the disadvantages of ballast water treatment systems. Thus, the hydrodynamic influences due to hull line variation of this kind of ships were studied, using the invariant cross-section area curve under the design draft to change the rise angle at bottom. Then numerical calculation was used to get the seakeeping at each angle. Two 3D models were constructed for 59000 DWT oil tankers and 35000 DWT bulk carriers, where the result of the bulk carrier was exposed.

Development of an automated ballast water treatment verification system utilizing fluorescein diacetate hydrolysis as a measure of treatment efficacy

Methods for verifying ballast water treatments in foreign vessels are needed to protect the Great Lakes from the discharge of live non-native organisms or pathogens. A prototype automated viability test system using fluorescein diacetate (FDA), a membrane permeable fluorogen, to differentiate live from dead bacteria and algae is described. The automated fluorescence intensity detection device (AFIDD) captures cultured algae or organisms in Detroit River water (simulated ballast water) on 0.2 μm filters, backwashes them from the filter into a cuvette with buffer and FDA for subsequent fluorescence intensity measurements, and washes the filters with sterile water for serial automated reuse. Preliminary manual versions of these procedures were also tested. Tests of various buffers determined N,N-Bis(2-hydroxyethyl)-2-aminoethanesulfonic acid, N,N-Bis(2-hydroxyethyl)taurine (BES) and 3-(N-morpholino)propanesulfonic acid (MOPS) at pH 7.0 to be the best buffers, causing the least spontaneous FDA breakdown without inhibiting enzymatic activity. Fluorescence in the presence of live organisms increased linearly over time, and the rate of increase was dependent on the sample concentration. Following simulated ballast water treatments with heat or chlorine, the fluorescence produced by Detroit River samples decreased to near control (sterile water) levels. Automated measurements of FDA hydrolysis with a reusable filter backwash system should be applicable to near real-time remote-controlled monitoring of live organisms in ballast water.

Application of immobilized TiO2 photocatalysis to improve the inactivation of Heterosigma akashiwo in ballast water by intense pulsed light

Ballast water exotic discharge has been identified as a leading vector for marine species invasion. Here immobilized TiO2 photocatalysis is introduced to improve the performance of intense pulsed light. For intense pulsed light/TiO2 photocatalysis, a typical inactivation of 99.89±0.46% can be achieved under treatment condition of 1.78Lmin−1 flow rate, 300V pulse peak voltage, 15Hz pulse frequency and 5ms pulse width. Moreover, within tested 220–260V peak voltage, 18.37–40.51% elevation in inactivation is observed in comparison with intense pulsed light treatment alone. The rough energy consumption of the tested intense pulsed light/TiO2 treatment system is about 1.51–2.51 times higher than that of the typical commercial UV ballast water treatment system. The stability of the photocatalytic reactivity and intactness of loaded TiO2 film is proved within 20-d’s test, while local erosion on stainless steel support is observed after 30-d’s test. The results indicate that intense pulsed light/TiO2 photocatalysis is likely to be a competitive ballast water treatment technique, while further measures is needed to reduce the energy consumption and ensure the performance of TiO2 film in a long run.

선박평형수 처리 시스템 효율 검증을 위한 해양 플랑크톤 생사판별시 Neutral red 염색법 적용 가능성 연구

In order to prevent the spread of non-indigenous aquatic species through the ballast water in commercial ships, International Maritime Organization (IMO) adopted in 2004 the International Convention for Control and Management of Ship`s Ballast Water and Sediments. The Convention mandates treatment of ballast water for most transoceanic voyages and its confirmation of treatment is made with plankton live/dead assay. Fluorescein diacetate assay (FDA), which produces bright green light for live phytoplankton, has been a de facto standard method to determine the survival of marine plankton, but its staining efficacy has been in dispute. In the present study, we examined the limitation of FDA, and compared its efficacy with Neutral red (NR) staining, another promising assay and widely used especially for zooplankton mortality. For all phytoplankton species studied in the present study, except Ditylum brightwellii, the staining efficiency was

Inactivation of microalgae in ballast water with pulse intense light treatment

The exotic emission of ballast water has threatened the coastal ecological environment and people’s health in many countries. This paper firstly introduces pulse intense light to treat ballast water. 99.9±0.09% inactivation of Heterosigma akashiwo and 99.9±0.16% inactivation of Pyramimonas sp. are observed under treatment conditions of 350V pulse peak voltage, 15Hz pulse frequency, 5ms pulse width and 1.78L/min flow rate. The energy consumption of the self-designed pulse intense light treatment system is about 2.90–5.14 times higher than that of the typical commercial UV ballast water treatment system. The results indicate that pulse intense light is an effective technique for ballast water treatment, while it is only a competitive one when drastic decreasing in energy consumption is accomplished.