For reasons of economy, this document is printed in a limited number. Delegates are 

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I:\MEPC\59\2-8.doc 

INTERNATIONAL MARITIME ORGANIZATION

IMO 

E

MARINE ENVIRONMENT PROTECTION 

COMMITTEE 

59th session 

Agenda item 2 

MEPC 59/2/8

 16 December 2008

 Original: ENGLISH

HARMFUL AQUATIC ORGANISMS IN BALLAST WATER

Application for Basic Approval of the AquaTriComb Ballast Water Treatment System 

Submitted by Germany 

SUMMARY

Executive summary: This document contains the non-confidential information related to 

the application for Basic Approval of the AquaTriComb Ballast 

Water Treatment System under the ìProcedure for approval of ballast 

water management systems that make use of Active Substances (G9)î 

adopted by resolution MEPC.169(57) 

Strategic direction: 7.1 

High-level action: 7.1.2 

Planned output: 7.1.2.4 

Action to be taken: Paragraph 5 

Related documents: BWM/CONF/36; MEPC 57/21; BWM.2/Circ.13 and BWM.2/Circ.15 

Introduction 

1 Regulation D-3.2 of the International Convention for the Control and Management 

of Shipsí Ballast Water and Sediments stipulates that ballast water management systems that 

make use of Active Substances to comply with the Convention shall be approved by 

the Organization. 

2 The ìProcedure for approval of ballast water management systems that make use 

of Active Substances (G9)î stipulates the required information (MEPC 57/21, annex 1, 

paragraph 4.2.1) and provisions for risk characterization and analysis (MEPC 57/21, annex 1, 

section 5) which according to section 6 of the Procedure (G9) should be evaluated by 

the Organization. 

3 The receiving competent authority in Germany has verified the application dossier and 

believes it satisfies the data requirements of Procedure (G9) adopted by 

resolution MEPC.169(57). In view of the findings presented in the confidential and 

non-confidential parts of the application dossier, the national Administration does not deem an 
MEPC 59/2/8 - 2 - 

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application for Final Approval necessary at this time. The national Administration will submit 

such an application only if clear guidance is received or new facts emerge during the current 

national application process which make such an application necessary. 

4 In accordance with BWM.2/Circ.13 and BWM.2/Circ.15, Germany therefore submits the 

non-confidential part of the manufacturerís application dossier in the annex. The complete 

dossier will be made available to the experts of the GESAMP-BWWG with the understanding of 

confidential treatment. 

5 The Committee is invited to consider the proposal for approval and decide as appropriate. 

***
MEPC 59/2/8 

I:\MEPC\59\2-8.doc 

ANNEX 

NON-CONFIDENTIAL INFORMATION ON THE AquaTriComb BALLAST WATER 

TREATMENT SYSTEM (GERMANY) 

SUMMARY 

Aquaworx ATC GmbH is applying for the Basic Approval of the AquaTriCombTM ballast water 

treatment system (BWTS) at the International Maritime Organization. 

The application of Aquaworx ATC GmbH for the Basic Approval of its ballast water treatment 

system AquaTriComb is based on the technologically safe and environmentally sound 

approach to abstain from any preparations and avoidance of reactive intermediates with the 

potential to pose a risk to the environment and/or to human health. The AquaTriCombô BWTS 

is designed to purposely avoid reactive intermediates like OHï radicals and consequently 

unwanted reaction products by using monochromatic UV-light and low frequency ultrasound. 

Based on definitions contained in the Methodology for information gathering and the conduct of 

work of GESAMP (MEPC 58/2/7, annex 4), substances generated by the treatment process of the 

AquaTriComb system are classified as: non Preparations are added and non-Active Substances 

are generated, Relevant Substance is defined as OHï radical and Other Chemicals are defined as 

possible by-products. 

To evaluate the impact of ballast water treatment on the production of Other Substances water 

samples were analysed chemically before and after the treatment process. All THM, LHKW, 

HAA, Bromophenol, Acetonitril, AOX, EOX and TRO (at all 32 substances or substance groups) 

measured before and after treatment were below Level of Quantification. One exemption being a 

Chloroform concentration in one sample before the treatment and is considered as an outlier. 

AOX could be measured in six samples before and after treatment at very low concentration at 

the Level of Quantification. Nitrite values showed a high variability above the Level of 

Quantification, in samples before as well as in samples after the treatment process. To verify a 

significant assertion regarding the variability of the results, a statistic test calculation was 

performed. The Mann-Withney U test statistic was used on the basis that data were not normally 

distributed. Results of the test statistic showed the data from samples before and after treatment 

were significantly not different, whereby they belong to the same data population. Therefore, it 

can be concluded that Nitrite is not generated by the treatment process. All Nitrite values before 

and after treatment are within the German, EU, EPA and WHO drinking water regulations. 

Hence, and based on the measured data, no risk for human health and the environment can be 

diagnosed. 

Under independent scientific examination the risk characterization and risk assessment was 

conducted regarding risks to the safety of ship, to human health and to the aquatic environment. 

Even if Nitrite values result from high background values originated in the test water and not 

from the treatment process, literature data of risk characterization and assessment for Nitrite was 

conducted. 

Analysis of the risk assessment demonstrates that no risks associated to the ship and its personnel 

neither to human health in general could be identified. Additionally it can be concluded that from 

this treatment process the magnitude of the hazard and the probability of risk exposure to the 

aquatic environment is of no concern. 
MEPC 59/2/8 

ANNEX 

Page 2 

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Based on analytic results and risk assessment, it can be concluded also that even if the precisely 

adjusted US (Ultrasonic oscillation) and UV technology generates OHï radicals by means of 

photons and cavitation bubbles, the concentration of OHï radical related Other Chemicals would 

be insignificantly low (not present, or at non-measurable concentrations) and risks to human 

health and to the environment can be demonstrably excluded. 

Therefore, this application for Basic Approval is connected to the appeal to whether the 

AquaTriComb BWTS proposal can be assessed according to Guidelines (G8) under the Ballast 

Water Management Convention. 

1 INTRODUCTION 

Aquaworx ATC GmbH is applying for the Basic Approval of the AquaTriComb Ballast Water 

Treatment System (BWTS) at the International Maritime Organization. 

The application is connected to the appeal to examine whether the AquaTriComb BWTS 

proposal can be assessed according to Guidelines (G8) of the Ballast Water Management 

Convention, following the guidance and format provided in the revised Draft Methodology 

(MEPC 58/2/7). This is due to the fact that no Preparations are intentionally introduced or 

generated with the technology. 

The AquaTriComb BWTS is composed of pre- and after-treatment modules to disinfect aquatic 

species in the ballast water. The treatment system comprises mechanical filtration in combination 

with ultrasonic (US) oscillation for filter self-cleaning, and ultraviolet-C (UV-C) radiation also in 

combination with ultrasound for self-cleaning of UV-C lamps. 

Due to the highly efficient combination of US oscillation and UV radiation the AquaTriComb

technology can abstain from any Preparations or chemical additives, which may pose a hazard to 

the population and/or to the environment. 

Because the US and UV-C technology is precisely adjusted to avoid the generation of OHï 

radicals, the concentration of the OHï radical related Other Chemicals is that low that risks to 

human health and to the environment can be demonstrably excluded. 

UV-C and US are especially acknowledged in portable- and waste water management to produce 

no, or little disinfection by-products by themselves (Liu et al. 2006) and have been identified as 

the most environmental friendly and effective methods for ballast water treatment (Gavand 

et al. 2007, Holm et al. 2008, Umweltbundesamt 2008). 

All reactive intermediates generated by UV-C radiation and ultrasound, and their potential 

reaction products during ballast water treatment occur naturally in seawater as products of 

sunlight induced photolytic activities (de Mora et al. 2000). In natural seawater reactive 

intermediates play an important role in the degradation of dissolved organic matter 

(DOM; largely uncharacterized long-chain organic molecules) enhancing biodegradability by 

micro-organisms of such substances and thus are important for the oceanic carbon cycle 

(de Mora et al 2000). However, the AquaTriCombô Ballast Water Treatment System is 

designed to purposely avoid reactive intermediates and consequently unwanted reaction products 

by using monochromatic UV-light and low frequency ultrasound (Liu et al 2006, Holm 

et al. 2008). 
MEPC 59/2/8 

ANNEX 

Page 3 

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The radical abandonment of any Preparations and avoidance of reactive intermediates qualifies 

the AquaTriComb technology as a highly effective and particularly environmentally sound 

ballast water treatment system. 

1.1 Ultraviolet radiation 

Ultraviolet technology is proving more and more successful and is being used as an 

acknowledged, cost-effective and reliable process. UV-C radiation as disinfection mean is well 

known for almost hundred years and is utilized widespread in the sector of disinfection of 

portable water, aquaculture waters, cooling water, hot water systems, ultra pure water, foodstuff 

industry, medicine, bottling of drinks, etc. It is used primarily wherever the microbiological 

requirements are particularly high, or where chemical disinfectants are unacceptable for quality 

or environmental reasons. It was found that especially a wavelength of 254 nanometer (nm) has a 

strong performance for disinfection. The low-pressure mercury germicidal lamps, which are used 

for the UV-disinfection have their maximum performance at a wavelength of 254 nm, and are 

similar to the absorption curve of the DNA. 

The use of UV-radiation as disinfection energy results in no change of the chemical compositions 

ph-value, temperature, salinity, taste, odour and colour of the solution being treated, and safety 

issues related to the handling of Relevant and/or Other Chemicals are eliminated. 

Ultraviolet disinfection requires a minimum dosage to be effective. The applied dosage is a 

function of the lamp intensity and the exposure time. These parameters are directly affected by 

equipment configuration, flow path of the water along the bank of lamps, the solids content, and 

the turbidity of the water to be disinfected. Compared to mid- or high-pressure lamps, 

low-pressure lamps can only operate with a lower performance, but they have a much better 

efficiency of about 45%. Using high- or mid-pressure UV lamps, the operating costs will be 

higher. Due to these facts, for the disinfection application of the treatment of ballast water 

low-pressure lamps are installed in the AquaTriComb BWTS. 

The low-pressure mercury vapour lamps consist of one hermetically closed discharge vessel. 

The gas inside is a vacuum seal against the outside. A voltage will be generated, which generates 

an electrical field between the electrodes. If the accelerated voltage is high enough, electrons will 

leave the electrodes and will be accelerated in the electrical field. If they crash with the gas atoms 

they discharge their kinetic energy. The atom or molecule decreases to a lower energetic level, or 

to the basis level. This released energy will normally be emitted in kind of radiations, so-called 

ìquantsî. Due to the energy in the atom, mercury is a very suitable gas for production of 

UV-radiation. 

It is a scientifically well-known fact that resistance of organisms like bacteria, viruses, moulds or 

fungal spores to ultraviolet radiation cannot be acquired. Most pathogenic germs are especially 

sensitive to UV-radiation. An important advantage of physical disinfection is that the sensitivity 

to UV still functions even when germs have already built up resistance to conventional 

disinfection measures such as alcohol, antibiotics, chlorinated chemicals, etc. A lot of 

conventional medical equipment and systems are now reaching the limits of their capabilities for 

disinfection and prevention when dealing with this problem. 
MEPC 59/2/8 

ANNEX 

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To address all the mentioned needs, UV-radiation as part of the AquaTriComb technology 

provides a powerful barrier to chemical contaminants while simultaneously disinfecting to avoid 

the dispersal of invasive aquatic species by ballast water from ships. 

The prime affect on organisms through short-wave and energetic UV-C radiation at 254 nm is 

based on a photo-chemical alteration of the DNA. The UV-C radiation is absorbed by pyrimidins, 

which form the basic elements of the organic base of the DNA string. Through covalent bindings 

of two neighbouring bases like thymin, pyrimidin dimers are generated. These pyrimidin dimers 

avert replication of DNA helix strings and cause mutations which result from unsuccessful 

DNA string repair mechanisms. Dimers are called ìbulky lesionsî: they disturb the helical 

configuration of DNA by means of partial decartelization resulting in reduced base matching 

ability. In addition, the UV radiation may result in direct alterations of the DNA morphology, for 

example, singular or double string fractures. Double string fracture can not be repaired and lead 

to cell mortality. In general, UV radiation result in defects of DNA repair abilities. 

The advantages of the application of UV-radiation as disinfection process are: 

- a purely physical disinfection process; 

- no Preparations will be added nor intentionally produced; 

- tried, tested and proven process approved by the DVGW (DVGW 2001); 

- water disinfected by UV-C radiation conforms with German portable water 

regulations (TVO, BGBl 2001); 

- no formation of health damaging by-products; 

- no production or storage of chemicals on board necessary, and no danger of over- or 

under-dosing; 

- only naturally occurring processes are used; 

- no change in physical parameters like pH-value, temperature, salinity, taste, odour, 

colour; 

- the use of UV-C radiation does not increase corrosion in ship compartments; 

- low maintenance and operating costs of the UV reactor compartments; and 

- low energy consumption needed by UV-C technology. 

UV-C radiation as disinfection technology of ballast water generates no harmful environmental 

effects to the aquatic environment. 

1.2 Ultrasonic oscillation 

The special advantage of ultrasonic (US) oscillation is the very fast and extremely high cleanness 

of the parts without any manual works to be carried out, and without any damage to the 

components. Also persistent impurities in, for example, borings and/or hollow spaces or at 

technically complicated parts will be removed by ultrasonic oscillation in seconds. 
MEPC 59/2/8 

ANNEX 

Page 5 

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Ultrasonic applications can be found, for example, in the aviation industry, laboratory medicine, 

textile and plastic industry, print and semi-conductor industry, surface engineering, etc. 

US cleaning and scouring is carried out with engine blocks, ball bearings, valves, filters, nozzles, 

breathing apparatus, mechanical measurement and calibration device, analytic strainer, etc. 

The germicidal effect of high frequency ultrasonic waves is assigned to cavitation and its direct 

after-effects like shearing, pressure, local calefaction and generation of free radicals by 

sonoluminescence (electric discharge) during treatment in fluid media. It results in affection of 

the cell wall, the cell membrane and other functional cell elements (Save et al. 1994). 

The advantages of the use of ultrasound are: 

- ultrasound (US) processes are purely physical processes; 

- the use of cavitation does not increase corrosion in ship compartments; 

- brushing or other means of cleaning is dispensable; 

- fast, highly efficient cleaning; 

- maintenance free, no personnel training needed; and 

- extremely low energy consumption. 

1.3 Technology overview 

Aquaworx ATC GmbH has developed a ballast water treatment system comprising pre- and after 

treatment modules. For the BWTS test plant the volume flow rate is designed at 250 m3

/h. 

The capacity of the volume flow rate can be designed by means of aligned up-scaling of the 

modules. During ballast water intake and at pre-treatment stage the ballast water is filtered 

through three (3) identically constructed MicroSintFilter (MSF) modules to remove particles and 

organisms. Pre-filtration allows very effective removal of organisms. 

Instead of so far applied 50 μm, the Aquaworx filter pore size equals 35 μm; filter material 

consists of a sintered high grade steel alloy. The automatically self-cleaning process of the filter 

modules is realized via permanent ultrasonic oscillation inside the filter tube. The ultrasound 

dissolves organic (bio film, agglutinations) and inorganic (e.g., calcium carbonate) accumulations 

from the filter tube, and organic agglomerations (detritus particles, phytoplankton colonies, slime 

creating phytoplankton) in the ballast water are broken off, and organisms are pre-treated. 

By means of reversed flow rate the backflush water is disposed off via separate piping. 

After-treatment is processed inside the UV-reactor via UV-C low-pressure mercury germicidal 

lamps and low-frequency ultrasound. The application of low-pressure UV-technology at 254 nm 

wavelength disinfects aquatic organisms very effectively. 

The most important impact of the ultrasound is the highly effective and permanent cleaning of 

the UV-emitter through the ultrasonic transmission along the full length of the UV-reactor, 

avoiding accumulations of bio films or inorganic salts on the quartz-crystal tubes. In addition, 

organic particles and phytoplankton colonies are broken off and organisms are pre-treated. 

Additionally, inside the UV-reactor the organisms are lethally affected by UV-light and 

ultrasound. 
MEPC 59/2/8 

ANNEX 

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Figure 1: Aquaworx ballast water plant consisting of three identically constructed MSF-modules 

(MicroSintFilter) and UVC reactor (AquaTriLight) 

As illustrated in Figure 1 the biological samples are taken in between the ballast water pump and 

the treatment plant (SP 01), in between the pre- and after-treatment (SP 02), and behind the 

after-treatment (SP 04). At the sampling port SP 03 the quality of the backwash after disinfection 

can be measured during de-ballast operations. 

The abiotic parameter as pH, conductivity, temperature, turbidity, oxygen content, flow rate 

volume and pressure are recorded during tests online via automatic sensors. The sensors are 

located at the ballast water feed pipe and behind the after-treatment. The piping diameter of the 

sampling points will be 1/8 of the ballast water pipe diameter. All valves are fitted with flanges, 

and electrical-driven and manual actuators. In addition to the valve positions ìOpenî and 

ìCloseî, intermediate positions are possible. 

In case of repair and maintenance or malfunction, the complete treatment plant can be by-passed 

with by-pass valves V01 and V03, and shut-off safety valves V02 and V012. 

1.4 Conclusion: technology overview 

The advantages of the AquaTriComb ballast water treatment plant ATC-250 may be 

summarized as follows: 

- Radical abandonment of any Preparations and avoidance of reactive intermediates; 

- Pore size of sinter filter (MSF modules) equals 35 μm; 

- During de-ballast operations the UV reactor completely disinfects the discharge water 

by means of pre-treatment (filter and ultrasound) and after-treatment (ultraviolet 

radiation and ultrasound); 
MEPC 59/2/8 

ANNEX 

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- The application of ultrasound provides a high clearance performance of the sinter 

tubes (filter) as well as the UV-tubes; 

- High disinfection performance through combination of low-pressure UV-C radiation 

and ultrasound; 

- Innovative technological optimization of filtration, ultrasound and UVC with 

extremely effective separation of particles and sediments, and mortifying of 

organisms allows for low-energy consumption of only; 

- As ultrasound effects are limited to the treatment plant components, cavitation effects 

on the shipsí piping and tank system are not possible, whereas the treatment plant 

components are designed to cope with cavitation; 

- The application of low-pressure radiation and very low-frequency ultrasound with 

extremely short-termed ultrasound impact (< 1 s) generated, based on analysis of 

treated water, none Other Chemicals during the treatment process; 

- By the application of UV-disinfection micro-organisms can not develop resistance; 

therefore also resistant pathogens (e.g., chlorine resistant) are inactivated by UV-C 

radiation; and 

- UV-C radiation and ultrasound do not affect physical parameters like salinity or 

pH-values of the ballast water. 

2 IDENTIFICATION OF PREPARATIONS, ACTIVE SUBSTANCES, RELEVANT 

AND OTHER CHEMICALS (G9: 4.1) 

2.1 Chemical identification 

Based on the definitions of ìPreparationsî, ìActive Substancesî, ìRelevant Chemicalsî and 

ìOther Chemicalsî as outlined in the revised Methodology for information gathering and the 

conduct of work of GESAMP-BWWG (MEPC 58/2/7) substances used or generated by the 

AquaTriCombô BWTS are classified as follows: 

2.1.1 Preparation means any commercial formulation containing one or more Active 

Substances including any additives. 

The AquaTriCombô BWTS does not utilize any ìPreparationî besides UV-light and low 

frequency ultrasound. 

Not applicable. 

2.1.2 Active Substance means a substance or organism, including a virus or a fungus that has a 

general or specific action on or against harmful aquatic micro-organisms and pathogens. 

The AquaTriCombô BWTS would produce ìPhotonsî emitted by the low-pressure UV (LPUV) 

system, and ìCavitation Bubblesî generated by the low-frequency ultra-sound (LFUS) system. 

The photon and cavitation bubble are entirely responsible for the inactivation of harmful aquatic 

micro-organisms and pathogens present in ballast water. 
MEPC 59/2/8 

ANNEX 

Page 8 

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With regard to the Methodology, both can not be classified as a substance or organism, therefore 

they are defined as reactive physical processes, not as Active Substances. For this reason 

non-Active Substances are generated by the treatment process. 

2.1.3 Relevant Chemical means transformation or reaction products that are produced during 

and after employment of the ballast water management system in the ballast water or in the 

receiving environment and may be of concern to the shipís safety, aquatic environment and/or 

human health. 

The AquaTriCombô BWTS regards only the hydroxyl radical (OHï) as a ìRelevant Chemicalî. 

However, the amount of OHï potentially produced in the system is extremely small. 

The OHï radical reacts at nearly diffusion controlled rates with any organic compound and exists 

for about 10-9 seconds. 

Therefore, OHï is considered not resident in the treated ballast water and causes no harm to the 

environment upon discharge. 

2.1.4 Other chemicals means reaction by-products that could be formed in the ballast water 

upon treatment with AquaTriCombô BWTS. 

During the process of OH-generation through photolytic and sonolytic processes secondary 

reactive intermediates and stable products can be formed. Most of the known stable products are 

non-toxic hydrocarbons. However, the formation of potential eco-toxicological Other Chemicals 

is partly known or can be inferred from application of UV and US in portable and wastewater 

treatment. Chemicals are specified under chapter 2.7. 

2.2 Background to characterize Reactive physical processes, Relevant and Other 

Chemicals 

2.2.1 Reactive physical processes (G9, 2.1.1) 

2.2.1.1 The photon 

According to the wave/particle-duality light can be considered as energy propagating as a wave 

and as a stream of photons with the constant speed of light. A photon is defined as a quantum of 

electromagnetic energy at a given frequency. Consequently, a photon possesses the more energy 

the shorter the wavelength. The energy characteristic for a photon at a specific wavelength is 

determined as: 

E = hc/λ (1) 

Where E is energy in Joule, h is the Planck constant, c is the speed of light and λ is the 

wavelength in meters. 

Ultraviolet light (UV) is part of natural sunlight. Electromagnetic wavelength spectrum of UV 

(UV spectrum) is 100 ñ 400 nm bordered by x-ray radiation (< 100 nm) and visible light 

(400 ñ 700 nm). According to the draft of ISO-standard on determining solar irradiances 

(ISO-DIS-21348) the UV spectrum is subdivided into UV-A (long wave, 315 ñ 400 nm), UV-B 

(medium wave, 280 ñ 315 nm), UV-C (100 ñ 280 nm), and vacuum UV (10 ñ 200 nm). 
MEPC 59/2/8 

ANNEX 

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UV-C can be used as a disinfectant against micro-organisms and pathogens including bacteria, 

viruses and phages (Hijnen et al. 2006). Therefore, UV-C is also referred to as germicidal light. 

Germicidal light is successfully applied in portable and wastewater management and the 

disinfection of water in aquaculture (Oppenl‰nder 2003). The applicability of UV in the 

treatment of ballast water of ships has been tested successfully in the laboratory and on the large 

scale (Welschmeyer et al. 2004). 

The basic process of disinfection with UV light is photolysis. Photolysis is the decomposition of 

a molecule by light. The strength of the chemical bond determines the photonic energy necessary 

for cleavage. Photonic energy of UV-C ranges from 4.43 to 12.40 eV. A photon of UV254 nm 

contains 4.89 eV photonic energy. 

For water disinfection two different UV techniques are widely used differing in their 

UV emission spectra. Middle Pressure UV (MPUV) lamps emit light over a broad range of 

UV and visible light. Low-pressure UV (LPUV) lamps used in the AquaTriCombô BWTS emit 

monochromatic light at the specific wavelength of 254 nm (UV254nm) to specifically take 

advantage of the DNA damaging effect, and reduce the formation of potential by-products. 

Absorption time for a photon by a molecule is in the range of nano- to picoseconds. It is 

generally accepted that photons leave no residuals in water. Accordingly, the use of UV for water 

disinfection and treatment (including ballast water treatment) is considered a purely physical 

process producing negligible amounts of by-products (DVGW 2001, USEPA 2006, 

Umweltbundesamt 2008). 

2.2.1.2 The cavitation bubble 

Sound is a form of energy. Sound is generated by the vibration of molecules in media (air, water, 

solid matter) and is travelling as a wave. The wavelength is defined as: 

 λ = c/f (2) 

where c is the speed of sound and f is the frequency. Acoustic sound frequency range is 20 Hz s 

inaudible and is referred to as ultrasound (US). 

The uses of Ultrasound (US) within this large range of frequencies are usually divided into two 

areas, i.e. low frequency US (20 to 100 kHz) and high frequency US (up to 10 mHz) 

(Mason & Lorimer 2002). Ultrasound has a broad range of application in industry, medicine and 

water treatment. In water treatment mechanical and sonochemical properties of US are used to 

remove (micro-) organisms, chemical pollutants, to break down aggregations of particles and to 

clean filtration units. Ultrasound applied to water has not enough energy to cause chemical 

reactions or mechanical disruption itself (Mason & Lorimer 2002). 

Chemical and mechanical properties rely on cavitation bubbles formed by US in liquids. 

Wave-like motion of US through water is characterized as an oscillation of compression and 

rarefaction. If the negative pressure during rarefaction is high enough the molecule structure of 

water is destroyed and gas filled cavitation bubbles (CBs) are generated. Cavitation bubbles 

collapse violently releasing a shock wave and create sheer stress causing mechanical disruption 

of material or organisms in close vicinity. According to this ìhot-spot-theoryî drastic localized 

conditions are produced: temperatures of 2,000 to 5,000°K and pressures of 1,800 to 3,000 atm 

occur in the CB. 
MEPC 59/2/8 

ANNEX 

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As so, the CB itself acts as a micro-reactor triggering chemical reactions inside and outside the 

bubble. Hydrogen radicals (H·) and hydroxyl radicals (OH·) can be generated inside the CB. 

Chemical reactions on the outside depend on the release of reactants formed inside the CB. 

The lifetime of a CB created at low frequency in water is in the range of μs to ms, where lifetime 

is mainly limited by collision. The CB itself is not resident in the water and consequently causes 

no harm upon release of treated ballast water. 

2.2.2 Relevant chemical (OHï) (G9, 2.1.4) 

We consider the hydroxyl radical (OHï) as the only Relevant Chemical formed during the 

process of ballast water treatment by the AquaTriCombô BWTS. Since OHï is highly reactive a 

number of chemicals could be produced in the treated ballast water theoretically. 

The eco-toxicological analyses of most Other Chemicals are specified under chapter 2.7. 

Formation of OHï can in general be initiated by both, UV-irradiation and US. In the following, 

we are going to show by literature review and the results of chemical testing of ballast water 

treated by the AquaTriCombô BWTS, that: 

.1 the AquaTriCombô BWTS is specifically designed to avoid the formation 

of OHï; 

.2 therefore, amounts of OHï produced are extremely small (at all, and in 

comparison to other techniques); and 

.3 consequently, potential formation of eco-toxicological relevant by-products is 

extremely low and concentrations are negligible and were not detectable in ballast 

water treated by the AquaTriCombô BWTS 

2.2.3 Other chemicals 

Oxidative degradation of organics by OHï is used in portable and wastewater disinfection. Very 

general, oxidative attack of OHï leads to the formation of the above-mentioned carbon centred 

radicals (RH2ï). The RH2ï immediately react with dissolved molecular oxygen producing a 

peroxyl radical (R-O-Oï). The R-O-Oï undergoes a vast variety of rearrangements and/or 

eliminations to form the final oxidation product (Rox). Final oxidation products are ketones, 

alcohols, aldehydes, molecular oxygen, aliphatic peroxides and H2O2 depending on the aliphatic 

skeleton of the attacked organic (Oppenl‰nder 2003). However, it has been demonstrated that the 

formation of carbonyls (e.g., aldehydes) at UV doses greater than 400 mJ/cm2 during wastewater 

and raw portable water disinfection is very low. 

Due to the unpredictable nature of the compounds potentially formed from DOM degradation in 

natural seawater by OHï, we focus on compounds where formation is known and which 

potentially cause a risk to the environment or are regulated in water quality acts 

(e.g., trichloroacetic acid is a registered herbicide and regulated by the German portable water act 

(BGBI 2001). Of most environmental concern are H2O2, Trihalomethanes (THMs) and 

Haloacetic Acids (HAAs) as well as other organic halides (RX). 

H2O2 occurs naturally in seawater and is formed by photolytic and biological processes or is 

introduced by rainfall. H2O2 is generated by the recombination of two OHï radicals: 

OHï + OHï H2O2

 
MEPC 59/2/8 

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Natural decay follows photolytic and biological pathways. Half-life of H2O2 in oligotrophic 

seawater estimated from decay rates under dark conditions is in the order of 16 ñ 224 h. 

Sea water concentration of H2O2 vary over a broad range (0.5 ñ 14 μg/l) depending on solar 

intensity, biological processes, rain input and the concentration of photolytic degradable DOM. 

H2O2 concentration in oligotrophic Atlantic surface water is about 100 nm (Bermuda triangle, 

Sargasso Sea) (Avery et al. 2004), while 400 nm H2O2 have been measured in coastal waters. 

The potential increase of H2O2 concentration in different salinities during ballast water treatment 

by the AquaTriCombô BWTS is shown by water analysis to be below the Level of 

Quantification. 

Formation of THMs, HAAs and RX are common and regulated disinfection by-products (DBPs) 

during waste and portable water sanitation using chlorine or chlorine species (Oppenl‰nder 2003, 

USEPA 2006). 

Natural seawater contains organic halogens from anthropogenic input (chemical industry, 

chlorinated Seawater as cooling agent in power plants, portable water disinfection) and natural 

sources (reactions of atmospheric organics with reactive halogens, production by algae, and 

sunlight induced photolysis of DOM). Concentrations of, e.g., THM and organic halides 

measured in the North Sea and the Baltic are in the order of 0.2 ñ 15 ng/l- while composition 

depends on sampling site. 

The potential increase of THM, HAA and RX concentration in different salinities during ballast 

water treatment by the AquaTriCombô BWTS is shown by water analysis to be below the Level 

of Quantification. 

Nitrite can be produced from Nitrate by photolysis. The yield of the photoreaction of Nitrate to 

Nitrite is sensitive to both the dissolved inorganic and organic carbon content of natural water. 

The nitrate concentration of untreated water influences directly the concentration of Nitrite 

produced as a consequence of UV and vacuum UV (VUV) irradiation. However, various doses of 

UV and vacuum UV irradiated natural organic matter were deemed non-cytotoxic. Similarly, a 

conducted Ames test showed no mutagenic response after various does of both UV and VUV 

irradiation. 

Together with Ammonium (NH4+) and Nitrate (NO3-), Nitrite (NO2-) is the most common ionic 

(reactive) form of dissolved inorganic nitrogen in aquatic ecosystems. All these ions can be 

present naturally as a result of atmospheric deposition, surface and groundwater runoff, 

dissolution of nitrogen-rich geological deposits, N2 fixation by certain prokaryotes 

(cyanobacteria with heterocysts, in particular), and biological degradation of organic matter. 

2.3 Data on effects on aquatic plants, invertebrates and fish, and other biota including 

sensitive and representative organisms (G9: 4.2.1.1) 

This chapter has the purpose to evaluate the effects of Preparations and its components to the 

organisms and the environment when released with the treated ballast water or accidentally 

during the process. 
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AquaTriCombô BWTS applies Low-pressure UV (LPUV) lamps emitting monochromatic light 

at the specific wavelength of 254 nm (UV254nm). At this wavelength, specifically DNA is 

damaged and the formation of by-products is reduced. 

Photons will not persist after the UVC exposure phase. Also OHï as Relevant Substance has a 

very short half-life and will not persist outside the BWTS system. Accordingly these two 

ìsubstancesî will be discussed below shortly with regard to their reaction mechanism and 

reactivity but not with regard to aquatic toxicity. 

Nucleic acids and Nucleotides as components of DNA and RNA absorb in the wavelength 

spectrum of 200 ñ 400 nm with a distinct maxima at 200 and 260 nm. Absorption of photon 

energy mediates the formation of various photolytic products in DNA and RNA inhibiting gene 

expression (e.g., base dimers, strandñ and double strand breaking, photohydrates). The most 

important, irreversible and lethal damage arises from the formation of pyrimidine base dimers, 

which block the translation and transcription of DNA and RNA, impeding replication and protein 

biosynthesis of micro-organisms (de Mora et al. 2000). The dimer formation is initiated by 

an exited state oxygen (Schreier et al. 2007). It has also been shown that UVC (100 ñ 280 nm) 

causes photolytic inactivation of various proteins potentially enhancing the germicidal effect 

(Chan et al. 2006 and references therein). 

Absorption time for a photon by a molecule is in the range of nano- to pico-seconds. The use of 

UV for water disinfection and treatment (including ballast water treatment) is considered a purely 

physical process, limited to the time of radiation exposure and producing negligible amounts of 

by-products (DVGW 2001, USEPA 2006, Umweltbundesamt 2008). Hence no residuals of the 

photon are to be expected in the treated ballast water. 

OH-radicals as ìRelevant Substanceî: Due to its high oxidizing potential OHï is by far the most 

reactive transient species that is produced in this process. It reacts at a nearly diffusion controlled 

rate with most organic substances. Its life time of about 1 nanosecond restricts its process related 

appearance to the ballast water treatment phase. No increased concentrations outside the plant are 

expected. 

2.3.1 Environmental toxicity of Other Chemicals ñ Nitrite 

In the case of the AquaTriComb BWTS Other Substances, which can theoretically be produced 

by the applied method as by-products within the process, could be of potential concern. 

According to chemical analyses, none of the Other Substances, discussed in this dossier, are 

determined above Levels of Quantification (see discussion of results chapter 5.2) except for 

Nitrite, where values are above the LoQ both for measurements before and after the treatment 

process. Investigated Nitrite concentrations before and after treatment process are statistically 

proven not significantly different (see chapter 5.2), what means the Nitrite values are not 

generated by the treatment process. Nevertheless in the following chapters we discuss literature 

data on environmental toxicity for Nitrite. 

2.3.1.1 Acute aquatic effects 

The PAN database contains data to the Algae growth inhibition test for 72 hours for Tetraselmis 

chuii and states an EC50 of 159 mg/l. The validity to consider this test as an acute test, however, 

is doubtful, as several algae generations will have grown over this time. Other and more reliable 

acute data comprise EC50 values for crustacea (48 hours), ranging between 27 and 193 mg/l and 

fish (LC 50) ranging from 11.2 mg/L (Oncorhynchus mykiss) to 226 mg/l (Anguilla anguilla). 
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2.3.1.2 Chronic aquatic toxicity 

Data on chronic aquatic toxicity are scarce due to the very short life span of the compound which 

is quickly converted to other nitrogen species in an aquatic environment. Reliable data for 

chronic (NOEC) toxicity were not available. 

2.3.1.3 Endocrine Disruption 

An endocrine effect of specifically nitrate but also Nitrite is being discussed, but no data are 

available so far (Guillette, 2006). Up to now Sodium Nitrite has not been listed as an endocrine 

substance in the EU prioritization list for endocrine disrupting substances. 

2.3.1.4 Sediment toxicity 

Under anoxic conditions it can be assumed that Nitrite is rapidly denitrified to, e.g., N2O. 

2.3.1.5 Bioavailability, bioconcentration and food web effects 

Accumulation of Nitrite has been shown to depend on the environment and is higher in 

freshwater fish, where Nitrite and chloride ions compete for the active branchial Cl- uptake 

system. In seawater, bioaccumulation of NO2- in the plasma is much lower. 

2.3.1.6 Overview over toxicological data of Nitrite 

Table 1 shows literature data of acute (EC50, LC50) toxicity for the organism groups algae, 

crustacean and fish for Nitrite. Reliable data for chronic (NOEC) toxicity were not available. 

Acute toxicity ñ EC50, LC50

Organism 

group 

Duration mg Nitrite /l Species Source 

Algae 72 h 159 (EC50) Tetraselmis chuii PAN Database 

Crustacea 48 h 27,1 (EC50)

193 (EC50) 

Metapenaeus ensis

Penaeus monodon 

PAN Database

PAN Database 

Fish 96 h 226 (LC50)

130 (EC50)

11,2 (LC50) 

Anguilla anguilla

Danio rerio

Oncorhynchus mykiss 

PAN Database

PAN Database

Kroupova et al. 2008 

Table 1: Literature data of acute (EC50, LC50) toxicity for the organism groups algae, 

crustacean and fish to Nitrite 
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2.3.1.7 Evaluation of the PNEC 

A PNEC of 0.01 mg/l has been determined by Bursch (2003) on the basis of chronic NOEC 

for three trophic levels1. This value has been suggested as the result of discussions by the 

competent authorities of the EU-member states. This level, however, has been critically 

discussed as the level is strongly dependent on the chloride concentration as well as other factors, 

and seemed unrealistically low. 

The Environmental Quality Standards for Nitrite have been proposed, based on data from 

Schwoerbel (1991) and addressing the differences in toxicity to aquatic organisms depending on 

the salinity of the ambient water: 

0-3 mg Cl-

/l ! 33 μg/l NO2

-

<3 ñ 7.5 mg Cl-

/l ! 164 μg/l NO2

-

<7.5 - 15 mg Cl-/l ! 296 μg/l NO2

-

<15 - 30 mg Cl-/l ! 394 μg/l NO2

- 

>30 mg Cl-/l ! 493 μg/l NO2

- 

2.4 Data on mammalian toxicity (G9: 4.2.1.2) 

In the case of the AquaTriComb BWTS Other Substances, which can theoretically be produced 

by the applied method as by-products within the process, could be of potential concern. 

According to chemical analyses, none of the Other Substances, discussed in this report, are 

produced above Level of Quantification (see discussion of results chapter 5.2) except for Nitrite, 

where values are above the LoQ both for measurements before and after the treatment process. 

Investigated Nitrite concentrations before and after treatment process are statistically proven not 

significantly different, what means the Nitrite values are not generated by the treatment process. 

Nevertheless, in the following chapters we discuss literature data on mammalian toxicity 

conditions for Nitrite. 

Information is taken from the background document for ìdevelopment of WHO Guidelines for 

Drinking water quality: Nitrate and Nitrite in Drinking water, WHO/SDE/WSH/07.01/16, 

WHO 2007î. 

2.4.1 Acute toxicity 

In a 13-week study in which Nitrite was given to rats in drinking-water, a dose-related 

hypertrophy of the adrenal zona glomerulosa was observed at all dose levels (100, 300, 1,000, 

or 3,000 mg of potassium Nitrite per litre). Increased methemoglobin (metHb) levels were seen 

only in the highest dose group. FAO/WHO (1995) concluded that the NOEL in this study 

was 100 mg of potassium Nitrite per litre (equivalent to 5.4 mg/kg of body weight per day 

expressed as Nitrite ion), because the hypertrophy seen at this dose was not significantly different 

from the controls. 

2.4.2 Effects on skin and eye 

No effects on skin or eyes have been reported. 

 

1

 Deriviation of the PNEC is documented in literature cited in Bursch (2003). 
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2.4.3 Repeated dose toxicity 

No repeated dose toxicity has been reported. 

2.4.4 Chronic toxicity 

One of the long-term effects of Nitrite reported in a variety of animal species is vitamin A 

deficiency; this is probably caused by the direct reaction of Nitrite with the vitamin. The most 

important effects reported in long-term animal studies were an increase in metHb level and 

histopathological changes in the lungs and heart in rats receiving Nitrite in drinking-water 

for two years. The LOAEL, which gave a metHb level of 5%, was 1000 mg of sodium Nitrite per 

litre; the NOEL was 100 mg of sodium Nitrite per litre, equivalent to 10 mg of sodium Nitrite per 

kilogram of body weight per day (or 6.7 mg/kg of body weight per day expressed as Nitrite ion) 

(Speijers et al., 1989). 

2.4.5 Developmental and reproductive toxicity 

Nitrite appeared to cause fetotoxicity in rats at drinking-water concentrations equivalent to 200 

and 300 mg of sodium Nitrite per kilogram of body weight per day, causing increased maternal 

metHb levels. However, after similar doses in feed in other studies, no embryotoxic effects were 

observed in rats. In a reproductive toxicity study in guinea pigs at dose levels of 0, 50, or 60 mg 

of sodium Nitrite per kilogram of body weight per day given by subcutaneous injection, fetal 

death followed by abortion occurred at the highest dose level. Teratogenic effects were not 

observed in reported studies in mice and rats (Speijers et al., 1989; FAO/WHO, 1996). 

2.4.6 Carcinogenicity and mutagenicity 

Nitrite is mutagenic and can cause morphological transformations in in vitro systems; mutagenic 

activity was also found in a combined in vivoñin vitro experiment with Syrian hamsters. The 

results of in vivo experiments were controversial (Speijers et al., 1989; FAO/WHO, 1996). 

At lower Nitrite levels, tumour incidence potentially induced by N-nitroso compounds, 

resembled those of control groups treated with the nitrosatable compound only. On the basis of 

adequately performed and reported studies, it may be concluded that Nitrite itself is not 

carcinogenic to animals (Speijers et al., 1989; FAO/WHO, 1996, 2003a). 

2.4.7 Toxicokinetics 

No data on toxicokinetics are available. 

2.5 Data on environmental fate and effect under aerobic and anaerobic conditions 

(G9: 4.2.1.3) 

In the case of the AquaTriCombTM BWTS Other Substances, which can theoretically be 

produced by the applied method as by-products within the process, could be of potential concern. 

According to chemical analyses, none of the Other Substances, discussed in this report, are 

produced above Level of Quantification (see discussion of results, chapter 5.2) except for Nitrite, 

where values are above the LoQ both for measurements before and after the treatment process. 

Investigated Nitrite concentrations before and after the treatment process are statistically proven, 

not significantly different, which means the Nitrite values are not generated by the treatment 

process. Nevertheless, in the following chapters we discuss literature data on environmental fate 

and effect for Nitrite. 
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2.5.1 Nitrite 

Together with Ammonium (NH4+) and Nitrate (NO3-), Nitrite (NO2-) is the most common ionic 

(reactive) form of dissolved inorganic nitrogen in aquatic ecosystems. All these ions can be 

present naturally as a result of atmospheric deposition, surface and groundwater runoff, 

dissolution of nitrogen-rich geological deposits, N2 fixation by certain prokaryotes 

(cyanobacteria with heterocysts, in particular), and biological degradation of organic matter. 

Nitrite is an important nutrient within the nitrogen cycle which is depicted below. 

Figure 2: The biological nitrogen cycle. Figures in parentheses denote the nitrogen 

oxidation state ANAMMOX: anaerobic oxidation of ammonia with 

Nitrite (redrawn from Richardson (2000)). 

2.5.1.1 Modes of degradation 

Typical concentration ranges of Nitrite in seawater have been stated to be 0.01 to 5 μg at/l 

(corresponding to 0.46 to 230 μg NO2-/l. Nitrite as an essential element of the nitrogen cycle is 

involved in a number of aerobic and anaerobic processes. Under oxic conditions, e.g., in the 

water column or in the oxidized upper sediment layer, chemolithotrophic bacteria, that build 

organic matter from CO2, use ammonia and Nitrite (NO2-) as electron donors in a process called 

nitrification, which yields energy for the organisms. The complete oxidation from ammonia to 

nitrate (NO3-) is carried out by two different groups of ìnitrifying bacteriaî that act in concert: 

Nitrosomonas and Nitrobacter. Nitrogen compounds are removed from the system by 

denitrification, which occurs under anaerobic conditions: Nitrate and Nitrite act as electron 

acceptors during anaerobic respiration. The nitrogen-compounds are finally reduced to gaseous 

compounds N2 or N2O. This process is the main process by which gaseous N2 is formed 

biologically. 
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2.5.1.2 Bioaccumulation and persistence 

Nitrite under normal ìstableî environmental conditions is a transient inorganic 

nitrogen-compound which is quickly transformed by oxidation or reduction processes (see 2.5.1). 

Under conditions of unbalanced nitrification, due to anthropogenic activities, problems may be 

created and are described in chapter 2.3.1. Clark et al. (2007) showed with samples from 

the North Atlantic Ocean, that Nitrite turnover rates due to ammonium and Nitrite oxidation can 

be highly variable in oligotrophic waters, ranging from < 1 day to > 10 days. Influential factors 

that regulate the activity of nitrifying bacteria and, thus, the nitrification rates in general, could 

comprise ammonium-availability, pH, temperature, oxygen concentration, competition for NH4, 

and organic carbon availability. Hence, concrete assumptions on the persistence of Nitrite are not 

possible, other than it is very little persistent when compared to non-nutrient compounds. 

Nitrite can accumulate in freshwater fish, as it competes with chloride ions for the active 

Cl-uptake mechanisms. Since the concentration of chloride ions in freshwater in low, presence of 

Nitrite can lead to NO2-accumulation. In seawater, the much higher chloride concentration limits 

the uptake, and hence leads to low uptake of Nitrites from surrounding water. Kroupova et al.

(2008) found elevated Nitrite levels in the plasma of fish (rainbow trout) exposed to 

concentrations of 1 mg/l NO2- and greater. 

2.5.1.3 Reaction with organic matter 

Nitrite does not react with organic matter in a relevant way. 

2.5.1.4 Potential physical effects on wildlife and benthic habitats 

No physical effects on wildlife and benthic habitats are assumed. 

2.5.1.5 Potential residues in seafood 

Of potential concern with regard to contamination of food with nitrogen compounds is the 

formation of nitrosamines which are formed in smoked fish products and in the human stomach 

as the result of the simultaneous presence of secondary amines and Nitrite. Most concern, 

however, seems to be directed towards the use of nitrogen compounds as preservatives, rather 

than their uptake by humans from fish which had accumulated Nitrites. As the knowledge on 

Nitrite accumulation is fairly new and results so far have been very variable, more research 

seems to be necessary in this respect. 
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2.6 Physical and chemical properties for the Preparations, Active Substances and 

treated ballast water (G9: 4.2.1.4) 

Physical/Chemical 

Property 

Active 

Substance: 

Photon

Relevant 

Chemical: 

OH-Radical

Other 

Chemical: 

Nitrite 

Treated 

Ballast 

water 

CAS Nr. n.a. 3352-57-6 14797-65-0 

Molecular weight [g/mol] n.a. 17.00734 46 

Melting point (°C) 

Boiling point (°C) 

Density 

Vapour pressure 

Water solubility 

Dissociation constant (pKa) 

Henryís law constant 

Log KOW 

Oxidation potential 

pH in solution basic 

Corrosivity to material 

Reactivity to container 

material 

Autoignition temperature 

(°C) 

Explosive properties 

Oxidizing properties 

Surface tension 

Viscosity 

(Thermal) stability and 

breakdown product 

Other physical and 

chemical properties 

Table 2: Physical and chemical properties for Physical reactive process (Photon), Relevant 

Chemical (OH Radical) and Other Chemicals (n.a.: not available, grey column 2 and 3: 

due to the transient existence, no data are available, column 5: data not available, 

column 4 Nitrite: no information possible, as it is an ion, all information would refer to 

the salt, whereby the different compounds would differ strongly depending on the 

cation, Data from Rippen (2005)) 
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2.7 Analytical methods at environmentally relevant concentrations (G9: 4.2.1.5) 

In chapter 2.2 the photon (UV-C radiation) and cavitation bubbles generated by 

the AquaTriComb BWTS have been identified as responsible for the inactivation of organisms, 

which in turn may result in OH-radicals. OH-radicals are extremely short-lived measured in 

nanoseconds, thus detection by conventional analytics is not feasible. Reactive effects of 

OH-radicals may result in reactive by-products like ozone, hydrogen peroxide or hyper bromate. 

Other possible OH-radicals related by-products are THMs, LHKWs, HAAs, Acetonitrils or 

Bromophenols. These by-products have been analysed by three laboratories.
MEPC 59/2/8 

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Basic Approval GloEnPatrol MEPC 57/2/4 

GESAMP-List MEPC 58/2/7 UBA-List 

Basic Approval AquaTriComb

AOX AOX AOX  EOX EOX 

 Nitrite (NO2)- Nitrite (NO2)-  Cl2 Cl2  Hydrogen peroxide Hydrogen peroxide  Ozone Ozone  Hyperbromate Hyperbromate 

Chloroform Chloroform Chloroform Chloroform Bromoform Bromoform Bromoform Bromoform Dibromochloromethan Dibromochloromethan Dibromochloromethan Dibromochloromethan Dichlorobromomethan Dichlorobromomethan Dichlorobromomethan Dichlorobromomethan Monochloracetic acid Monochloracetic acid Dichloroacetic acid Dichloroacetic acid Trichloroacetic acid Trichloroacetic acid Monobromoacetic acid Monobromoacetic acid Monobromoacetic acid Monobromoacetic acid  Dibromoacetic acid Dibromoacetic acid Dibromoacetic acid  Tribromoacetic acid Tribromoacetic acid Tribromoacetic acid Bromochloroacetic acid Bromochloroacetic acid Bromochloroacetic acid Dibromochloroacetic acid Dibromochloroacetic acid Dibromochloroacetic acid  Bromodichloroacetic acid Bromodichloroacetic acid 
I:\MEPC\59\2-8.doc 

Basic Approval GloEnPatrol MEPC 57/2/4 

GESAMP-List MEPC 58/2/7 UBA-List 

Basic Approval AquaTriComb

 1,2- dibromoethane 1,2- dibromoethane  1,2,3-trichloropropane 1,2,3-trichloropropane  2-chlorotoluene 2-chlorotoluene  4-chlorotoluene 4-chlorotoluene 1,2-dibromo-3-chloropropane 

1,2-dibromo-3-chloropropane 

1,2-dibromo-3-chloropropane 

 1,2,3-tribromobenzene 1,2,3-tribromobenzene 1,1,1-Trichlorethan 1,1,1-Trichlorethan Carbon tetrachloride Carbon tetrachloride Tetrachlorethen Tetrachlorethen  Monobromoacetonitrile Monobromoacetonitrile Monobromoacetonitrile  Dibromoacetonitrile Dibromoacetonitrile  Bromochloroacetonitrile Bromochloroacetonitrile  2,4-dibromophenol 2,4-dibromophenol  2,6-dibromophenol 2,6-dibromophenol  2,4,6-tribromophenol 2,4,6-tribromophenol 2,4,6-tribromophenol 

Table 3: List of substances identified as possible by-products and analysed by Aquaworx. 
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In Table 3 three different lists identify disinfection by-products (column 1 to 3), non-conformity 

between the lists is marked ìyellowî: 

- Column 1 as given in MEPC 57/2/4 is a combination of technologies similar to 

AquaTriComb BWTS; 

- Column 2 according to GESAMT Ballast Water Group, MEPC 58/2/7; and 

- Column 3 according to recommended list of possible by-products as given by German 

Federal Environment Agency (Umweltbundesamt Deutschland, UBA). 

Water samples were analysed regarding the substances from all lists as shown in column 4. 

The following Table 4 shows Other Chemicals including Levels of Quantification and 

identification numbers of the standardized methods analysed by three laboratories. 
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Parameter Level of 

Quantification Methods 

Nitrite (NO2) 0,007 mg/l DIN EN 26 777 1993-04 

AOX 0,02 mg/l DIN EN 1485: 1996-11 

EOX 0,002 mg/l DIN 38141-S17 1989-11 

THM: 

Chloroform 

Bromoform 

Dibromochloromethan 

Dichlorobromomethan 

0,02 μg/l EN ISO 10301 1997-04 

LHKW 

1,2- dibromoethane 

1,2,3-trichloropropane 

2-chlorotoluene 

4-chlorotoluene 

1,2-dibromo-3-chloropropane 

1,2,3-tribromobenzene 

1,1,1-Trichlorethan 

Carbon tetrachloride 

Tetrachlorethen 

0,02 μg/l EN ISO 10301 1997-04 

HAA: 

Monochloracetic acid 

Dichloroacetic acid 

Trichloroacetic acid 

Monobromoacetic acid 

Dibromoacetic acid 

Tribromoacetic acid 

Bromochloroacetic acid 

Dibromochloroacetic acid 

Bromodichloroacetic acid 

1,0 μg/l DIN 38407 F25 

Bromophenols: 

2,4-Dibromophenol 

2,6-Dibromophenol 

0,01 μg/l GC-MS after derivatization and 

extraction 

2,4,6-Tribromophenol 0,04 μg/l GC-MS after derivatization and 

extraction 

Acetonitrils: 

Monobromoacetonitril 

Dibromoacetonitril 

Bromchloroacetonitril 

1,0 μg/l US EPA Method 551.1 

TRO: Cl2, H2O2, O3, BrO All substances: 

0,05 mg/l EN ISO 7393-1 2000-04 (G4-2) 

Table 4: Possible by-products including Levels of Quantification and certified methods analysed 

by three certified laboratories. 
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Certified standards are followed with regard to the samples at the beginning of every analytical 

run. Every method is also included in periodical participation on extern laboratory tests except 

for Bromophenols, see below. 

Levels of quantification 

According to the report of the seventh meeting of the GESAMP-Ballast Water Working Group in 

annex 5 (MEPC 58/2/8) Levels of Quantification (LoQ) for THMs and HAAs for surface waters 

are recommended as 0.01 ñ 0.05 μg/l. The laboratories involved in our analysis were able to 

reach LoQs for THM, LHKW and Bromophenols of 0.02 μg/l, which meets the recommended 

range. In the case of the HAAs, experts of the laboratories have spent considerable effort to find 

methods or laboratories, which are able to meet the recommended LoQ. The effort to find a 

solution also included the attempt, to establish and optimize a standardized analytical method 

regarding this special demand. As the best result a laboratory was able to reach a LoQ for HAAs 

with 1 μg/l. Experts of the laboratory explain the background of the applied analytical method 

and the reason why the LoQ of 0.01 ñ 0.05 μg/l could not be reached (see below analyse method 

of HAAs). 

Analyse methods 

The analyses of AOX/EOX have been carried out according to DIN EN 1485: 1996-11 

and DIN 38141-S17 1989-11 with a coulometer of company Umcat. The parameters are so called 

summation parameter. They detect certain matters in their complexity and allow for 

interpretations which are important with regard to the advanced analysis strategy and to the 

plausibility control. As to AOX and EOX it is the sum of the halogenated absorbable and 

extractable compounds within the probe. The measures to assure quality for such analyses are 

defined by DIN. That is besides the blank value of the instrument, the blank value is carried out 

for the analysis including a regular calibration by means of external standards. For the day-to-day 

control a control standard is analysed and control readings shall detect methodical problems. 

Further for AOX regular participation of interlaboratory tests is carried out. 

Lightly volatile halogenated hydrocarbons and Trihalogenmethans have been analysed according 

to DIN EN ISO 10301 1997-04 with a gas-phase chromatograph with mass spectrometric 

detection and headspace sampler of Messrs. Agilent. The advantage of detection with a mass 

spectrometer is the definite identification and classification of the detected substance. 

The application of the SIM method, which accounts for the specific masses of the detected 

substances only, allows for very small LoQ. For these parameters the laboratory also regularly 

participates in interlaboratory tests. The quality assurance methods for these analyses are 

determined by DIN. That is besides the blank value of the instrument, the blank value is carried 

out for the analysis including a regular calibration by means of external standards. For the day-to-day 

control a control standard is analysed and control readings shall detect methodical problems. 

Nitrite is analysed according to DIN EN 26 777 1993-04 with a photometric procedure. At a 

specific wavelength the colour reaction is detected with a reagent. The procedure for quality 

assurance is according to DIN and includes a daily calibration, a blind value as well as control 

standards which are documented on control charts. 

The analysis of ozone, hydrogen peroxide and hyper bromate has been done in situ with the 

method for free chlorine as the sum of the existing oxidants in water. A mobile photometer has 

been applied which allows for the measurement of the colour intensity as direct reaction with 
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N,N-Diethyl-1,4-phenylendiamin and formation of a reddish compound at ph 6.2 to 6.5 

according to EN ISO 7393-1; 2000-04 (G4-2). 

Bromophenols were analysed with a gas-phase chromatograph with mass spectrometric detection 

and autosampler of the company Agilent. Analysis is done after derivatization as methyl ester. 

The advantage of detection via mass spectrometer is to found in the definitely identification and 

in the clear classification of the investigated substances. By means of using the SIM method, 

which considers only specific masses of analysed substances, very low LoQs can be achieved. 

For these parameters the laboratory can not take part in interlaboratory tests (ring tests), because 

these parameters are until now not implemented in ring tests. Quality control measures for this 

analysis include beside blind values of the instrument, blind values for the method also 

permanent calibration with external standards. For the daily control a control standard is 

analysed. 

Difficulties arose to find a laboratory to analyse halogenated Acetonitrils. Analysis of these 

substances is very seldom asked for, and therefore laboratories have rarely established respective 

certified analytic methods. The laboratory analysed Acetonitrils according to the US EPA 

method 551.1. With regard to the sound solubility of the Acetonitrils the salt sodium sulphate 

was added (shifting of the solution equilibrium) and subsequently extracted with MTBE. 

The extract will be concentrated and then analysed with GC/MS. All three Acetonitrils are 

measured with a LoQ of 1 μg/l. 

Determination of HAA was performed following the guideline EN ISO 23631:2006. 

The analytical range was within 0.5-10 μg/l according to the standard solutions employed, 

depending on the matrix of the samples, respectively. Our estimated limit of quantitation was 1 μg/l, 

which is appropriate for the analytical range stated above. Description of method and analytical 

constraints: 200 ml of aqueous test solution is adjusted to pH 1 and extracted after addition 

of 20g sodium chloride with 20 ml MTBE. Subsequently, the organic extract is removed and 

concentrated to 1 ml. After derivatization of the analyte with diazomethan, concentrations were 

assessed by means of GC-ECD. However, since the compounds under study are very polar 

extraction is rather difficult and will be eventually not complete. Furthermore, it will not be 

possible to decrease the limit of quantitation by increasing the sample volume thus leading to 

higher concentrations of the analyte in the organic extract. This is due to the fact the matrix will 

also be concentrated in this way, leading to unfavourable disturbances of the detection 

by GC-ECD. 

2.8 Quality control/quality assurance (G9: 4.2.4) 

For the laboratories the Analytic Quality Assurance (AQS) is of utmost importance. It is the 

prime aim to deliver reliable analytic results of defined quality. Therefore, one of their main 

targets is the quantitative assessment of all applied analyse methods, if necessary the 

improvement of these methods, and to ensure and to document the achieved quality throughout 

the analytic routine. 

To meet this challenging target a quality management system (QM) is implemented. This system 

governs all quality-related routines and provides the pre-conditions for continuous quality 

improvement according to DIN EN ISO 17025 and ìGood Laboratory Practiceî (GLP). 

To comply with the high demands regarding analyses in the water pertaining enforcement, the 

existing AQS measures have been aligned to the ìRahmenempfehlungen der 

L‰nderarbeitsgemeinschaft Wasser (LAWA) f ̧r die Qualit‰tssicherung bei Wasser-, 
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Abwasser-und Schlammuntersuchungenî (basic recommendations of the working group water 

for the quality assurance of water, waste water and sludge analyses). On this basis IBEN is 

accredited according to DIN EN ISO 17025 and holds several other concessions for legally 

regulated sectors. That means that in addition to internal quality assurance external controls in 

form of mandatory and periodic interlaboratory tests have to be carried out. This in turn 

guarantees the permanent control of services. Participation in interlaboratory tests is obligatory 

by means of the accreditation, that is, that these tests have to be performed to maintain the 

accreditation. 

3 USE OF ACTIVE SUBSTANCE(S) 

Although the AquaTriComb does abstain from any Preparations the highly efficient 

combination of ultraviolet radiation and ultrasonic oscillation generates photons and cavitation 

bubbles. Nor photon or cavitation bubbles are residual in the treated ballast water and thus have 

no toxicological effects upon discharge into the environment. 

The OH radical, which can be generated by photons and cavitation bubbles reacts at nearly 

diffusion controlled rates with organic compounds and exists for about 10-9 seconds. Therefore, 

OHï is considered not resident in the treated ballast water and causes no harm to the environment 

upon discharge. 

The OH radical related by-products are discussed above in chapter 2, and data on analysed water 

samples showed none of the investigated substances are generated by the treatment process 

regarding to the applied Levels of Quantitation. For this risks to human health and/or to the 

environment can be demonstrably excluded. 

3.1 Operational overview and process description 

The AquaTriComb BWTS will be installed in line behind the ballast water pumps with a 

bypass pathway. Both ballast water intake flows, as well as de-ballasting flows, will be directed 

via the whole treatment system. 

Two of the three MicroSintFilter modules are permanently active in the filtration process, the 

third module is in cleaning and stand-by mode. 

Pressure difference in front of and behind the treatment system will be approximately 1 bar, 

depending on the contamination of the water. From the system the ballast water is directed into 

the ballast tanks and via the ballast water pump(s) into the sea, respectively. 

3.2 System monitoring and control, crew interaction 

The AquaTriComb treatment plant is fully automated and completely self-contained with 

electronic steering, switchboard, and control panel including emergency shut-off device. 

The plant can be readily pre-mounted in accordance to the shipís specifics for connection to the 

shipboard power supply system. 

The monitoring and control devices include flow meters, pressure transmitter, electronically 

driven actuator valves with manual setting option, and sample ports. Also operating hours 

counter and malfunction writer will be installed (data logging). 
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Depending on the grade of automation of the existing ballast water system, typically the plant 

requires no additional action by the crew or alterations of current ballast water procedures. If any, 

minor modifications to ballasting procedures are ship specific and will be carefully considered 

during system engineering and installation. 

3.3 System requirements 

Space requirements

The treatment plant is designed as a modular system ñ all single filter modules and the 

UVC-reactor can be installed independently. For this reason in the case of refitting ships with 

AquaTriComb BWTS the existing space can be optimally used. 

As the MSF modules as well as the UV-reactor are vertically installed sufficient top space has to 

be foreseen for exchange of filter module and US oscillators, respectively. 

Personnel requirements

The treatment plant is designed to need minimum input from the crew. The crew member 

performs ballasting and de-ballasting procedures as normal and the AquaTriComb starts 

operations after activation of switch-on device. Further, Aquaworx is offering a training unit to 

the key shipboard personnel to get familiar with the system. 

Maintenance requirements 

The ultrasonic tube oscillators need to be exchanged at the earliest after approximately 16,000 

and 20,000 operating hours, the low-pressure mercury germicidal lamps after about 12,000 

operating hours. All other system components do not need any extra maintenance and will be 

integrated into the routinely applied shipboard plant maintenance schedule. Depending on the 

ship and the shipís trade a maintenance contract will be signed considering periodic reviews and 

other specifics. 

Handling of waste and replaced parts of the treatment system 

During the treatment process no liquid or solid waste appears. Only in the case of completed 

operating hours, or broken, or out-of-order UVC lamps, the glass tubes of the lamps have to be 

changed and disposed. In case of broken glass no hazard appears to the ship crew, because the 

mercury is as amalgam accumulated as a thin layer on a special spot the inner glass tube. Broken 

glass can be disposed on board similar to other glass waste. In case a whole lamp be removed 

from the reactor, the lamp should be kept on board for recycling by Aquaworx or by the lamp 

manufacturer. 

3.4 System locations 

The AquaTriCombBWTS can be located in any suitable and convenient location dependent on 

the shipís design. The naval architects and marine engineers of Aquaworx will consider and 

discuss with the client to keep engineering for the integration of the BWTS at a low level, to not 

interfere with normal cargo operations and required crew activities, and to look to placement 

opportunities next to the ballast water pumps to minimize the piping length. 
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3.5 Operational safety features and alarms 

As not otherwise permissible and acceptable in the shipping industry, all system components will 

be of maritime standard type and will have the appropriate approval of the classification society 

and/or relevant regulatory authority. 

No rotating parts or other physical hazards are originated by the AquaTriComb BWTS; hazards 

from chemicals or other Active Substances are excluded. 

At least the following alarms will be indicated at the BWTS switchboard: 

- UV-reactor operational readiness after approximately 5 minutes warm-up phase after 

switch on (red to green); 

- BWTS in by-pass mode (red); and 

- General malfunction (red) 

These alarms may also be indicated at the Engine Control Room (ECR), the Cargo Control Room 

(CCR) and at the bridge, or a common alarm will be installed there. 

An emergency shut-off device will be installed at the BWTS and at the ECR. 

3.6 Procedures and management measures 

The operation of the AquaTriComb BWTS is to be integrated into the Ship Safety Manual 

(SMS) as an integral part of the ISM2 documentation. 

That is, a procedure has to be developed based on the AquaTriComb BWTS Guidelines for the 

proper operation of the treatment plant. This procedure also describes the service and 

maintenance intervals and regular preventive maintenance measures (routine check of sea chest, 

piping corrosion and related shipboard routines). 

3.7 Evaluation of Management Measures 

Preventing exposures and emergency situations starts with proper engineering and installation of 

the AquaTriComb BWTS on board the ship. The management measures discussed above 

consider location, training and handling of the plant. In connection with the risk assessment these 

measures are considered to be adequate to avoid uncontrolled or emergency situations and to 

operate the ballast water treatment plant in a safe manner. 

4 MATERIAL SAFETY DATA SHEETS (G9:4.2.7) 

Since Material Safety Data Sheets (MSDS) for the Relevant Chemical OH radical does not exist, 

MSDS of several investigated Other Chemicals can be found in Annex C. 

 

2

 International Safety Management (ISM) Code: International Code for the Safe Operation of ships and for 

Pollution Prevention, SOLAS chapter IX. 
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5 RISK CHARACTERIZATION 

In this chapter, the information, displayed in the foregoing chapters concerning hazard 

identification, exposure assessment and dose-response assessment are summarized in terms of 

risk assessment. 

5.1 Screening for persistence, bioaccumulation and toxicity (G9:5.1) 

Photons and cavitation bubbles as well as hydrogen radicals as Relevant Substance have a very 

low life span of less than nanoseconds (see chapter 2.3.1) and therewith are neither persistent, nor 

do they bioaccumulate or induce toxic effects outside of the direct treatment chamber. 

Of potential concern are Other Substances, which can theoretically be indirectly produced by the 

applied method as reaction products within the process. Whether the statistic results of measured 

Nitrite values showed, the treatment process is not responsible for detected Nitrite values, 

however the risk characterization will focus on Nitrite. 

5.1.1 Persistence (G9: 5.1.1.1) 

Nitrite is a nutrient and either nitrified or denitrified quickly ñ depending on whether aerobic or 

anaerobic conditions prevail. A half-life of 10 minutes has been estimated. 

5.1.2 Bioaccumulation (G9: 5.1.1.2) 

Bioaccumulation of Nitrite by freshwater fish is higher than by marine fishes because Nitrite 

competes with chloride for uptake channel processes. No bioaccumulation factor is available. 

5.1.3 Toxicity (G9: 5.1.2.3) 

In general, few studies of chronic toxicity are considered to be reliable, and often documentation 

of experimental set-ups is poor. 

Information on acute toxicity is more abundant. 

Toxicity of Nitrite to fish even occurs at natural concentrations or when nitrification becomes 

unbalanced due to anthropogenic activities. The toxicity of Nitrite depends on a large number of 

factors, the most important being water chemistry and especially chloride concentration. Data for 

acute toxicity are shown in Table 2. 

5.1.4 PBT Criteria (G9: 6.4.1, Table 1) 

In Table 5 the PBT criteria (Persistence, Bioaccumulation and Toxicity) are shown for Nitrite. 

Compared with data from Procedure (G9), Table 1: Criteria for identification of PBT substances 

these results show that persistence and bioaccumulation rates for the selected substances do not 

exceed the criteria from Table 1 in Procedure (G9). 
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Other substance Persistence Bioaccumulation Toxicity 

Nitrite Turnover has been 

approximated to be 

less than a day to 

more than 10 days 

(latter in oligotrophic 

environments). 

No BCF has been 

determined 

Data for acute toxicity 

are shown in table 2 

Table 5: Summary of persistence, bioaccumulation and toxicity criteria for Nitrite 

5.2 Evaluation of the treated ballast water (G9: 5.2) 

To evaluate the impact of ballast water treatment on the production of Other Substances samples 

were analysed chemically before and after the treatment process. 

Test medium Salinity (PSU) 

Freshwater 0 

Brackish Water 18.9 ñ 19.5 

Saltwater 31.6 ñ 33.1 

Table 6: Range of salinities during sampling investigating by-products with temperature ranges 

from 16.1 to 17.8°C. 

Treatments were carried out at three different salinities (Table 6) and with two to three parallels 

in several runs (two to four) each before (pre) and after (post) treatment. All TRO, HAA, THM, 

LHKW, Acetonitrils and Bromophenols measured in samples before and after treatment were 

below Levels of Quantification. 

Except for Chloroform, where some results for samples before and after treatment at or slightly 

above the LoQ (0.02 μg/l) were measured. These values indicate, that Chloroform background 

concentrations within the test water in the Bremerhaven harbour waters are to characterize 

around 0.02 μg/l. From this results can not be concluded, that the treatment process cause higher 

levels for Chloroform. For this reason values near to the LoQ will not be considered in further 

discussion. An exemption is the detection of one value for Chloroform concentration before the 

treatment. As this is the only higher value clearly above LoQ and was measured in the sample 

before the treatment, it is considered as an outlier without further concern for the evaluation. 

AOX could be measured in some samples at very low concentrations at the LoQ (0.02 mg/l), in 

samples before and after treatment and here the same can be applied as for Chloroform. 

Nitrite concentrations especially for brackish and salt water are above the LoQ and show a high 

variability in samples in both treatments, before and after the BWTS. Regarding this variability 

and to obtain a significant conclusion, if the data from samples before treatment are different 

compared to data after treatment a statistic analysis has been performed. For the statistic 

evaluation the program SYSTAT 12 was used. Data of freshwater samples could not be tested, 

because the variability was too low, to apply test statistic for investigation of significance of the 

variability. Because the data of brackish and salt water samples were not normally distributed, 

the normally non-parametric Mann-Whitney U Test Statistic including the appropriate 

descriptive statistic was applied. 
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Figure 3: Box plot of descriptive statistic as part of the Mann-Whitney U Test Statistics of 

Nitrite concentrations before and after treatment of brackish water (Vor: before treatment, 

Nach: after treatment, middle line in the box: median, outer lines of the 

box plot: 25% and 75% quartile ñ representing 25% or 75% of the 

data within this range, n=14) 

Figure 4: Box plot of descriptive statistic as part of the Mann-Whitney U Test Statistics of 

Nitrite concentrations before and after treatment of salt water (Vor: before treatment, 

Nach: after treatment, middle line in the box: median, outer lines of the 

box plot: 25% and 75% quartile ñ representing 25% or 75% of the 

data within this range, n=14) 

In Figures 3 and 4 the box plots (descriptive statistic) of the estimation are shown. Number of 

data for brackish as well as for salt water for calculations before and after treatment were 14. 

The result of the test statistic shows the estimated P-values (0.27 for brackish water, 0.16 for salt 

water) were below the specified significance level of 95% (α = 0.05). It can be concluded that 

Nitrite concentration from samples before and after the treatment belong to the same data 

population ñ means they are significantly not different. From this it can be concluded that the 

Nitrite concentrations measured in samples were not generated by the treatment process. 

All Nitrite values before and after treatment are still within the German drinking water 

regulation, where 0.5 mg/l are the maximal allowed concentration at the userís tap. Hence no risk 

to human health and/or to the marine environment can be deduced on the basis of these data. 
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5.3 Risk characterization and analysis (G9: 5.3) 

5.3.1 Reaction with organic matter (G9: 5.3.3) 

Nitrite does not react with organic matter. 

5.3.2 Characterization of degradation route and rate (G9: 5.3.5) 

Half-life of Nitrite has been estimated to be around 10 minutes, but turnover times strongly 

depend on the ambient conditions, especially the activity of nitrifying or denitrifying bacteria and 

the oxygenation of the water. As Nitrite is an essential part of the nitrogen cycle, their 

consumption is fast. 

5.3.3 Prediction of discharge and environmental concentrations (G9: 5.3.8) 

On the basis of the chemical data determined in samples from the treated ballast water there is no 

indication of release of harmful substances, resulting in an increase of environmental 

concentrations. 

5.3.4 Assessment of potential for bioaccumulation (G9: 5.3.7) 

As there is no indication for the release of harmful substances, the actual potential for 

bioaccumulation is considered to be very low. 

5.3.5 Effect assessment on aquatic organisms and sediment 

Due to their extremely low lifetime, direct effects of photons and cavitation bubbles are not 

anticipated. In the effect assessment, only Other Chemicals as Nitrite are considered. 

5.3.5.1 Risks to aquatic organisms 

Acute and chronic toxicity data have been displayed in chapter 2.3.2. 

The toxicity of Nitrite depends on a large number of factors, the most important being water 

chemistry and especially chloride concentration. With higher chloride concentration, toxicity 

decreases. Accordingly Schwˆrbel (1991) proposed the following environmental criteria: 

0-3 mg Cl-/l ! 33 μg/l NO2

- 

<3 ñ 7.5 mg Cl-/l ! 164 μg/l NO2

-

<7.5 - 15 mg Cl-

/l ! 296 μg/l NO2

-

<15 ñ 30 mg Cl-

/l ! 394 μg/l NO2

- 

>30 mg Cl-/l ! 493 μg/l NO2

- 

Bursch (2003) suggested a PNEC of 0.01 mg/l. This value correspond with the guidance values 

of the Fish Directive of the EU for Salmonid and for Cyprinid waters of ≤0.01 mg/l NO2- 

and ≤0.03 mg/l NO2-, respectively (EU Directive 2006/44/EC). 
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5.3.5.2 Risks to sediments and for bioaccumulation and secondary poisoning 

Since Nitrite as an ion and therewith completely water soluble, for Nitrite does not exist a log 

KOW value. Therefore, neither sediment toxicity, nor bioconcentration or magnification effects, 

including secondary poisoning are considered to be of concern. 

5.3.5.3 Risks to humans 

No effects on humans are anticipated during the process (see Human health risk chapter). 

Exposure to treatment water could occur accidentally (e.g., people falling overboard). 

As described above, concentrations of Other Chemicals in the treated ballast water are, however, 

considered to be too low to cause effects in aquatic organisms and will be unlikely to cause 

effects to humans that may become accidentally exposed to a mixture of treated ballast water and 

water. 

Nitrite is strictly regulated in drinking water due to its known interference with the 

oxygen-carrying capacity of the blood which poses especially small children in danger. 

Drinking water standards from the WHO, EPA, EU and Germany are depicted below 

(partly additional conditions with regard to Nitrate are included, which have been omitted here, 

as the focus is on Nitrite). 

Regulatory body Nitrite 

WHO 3 mg/l3 Guideline value 

EPA 1 mg/l4 Maximum contaminant level 

EU 0.5 mg/l5 Quality standards have to be set by the member 

states but should not exceed the values of 

Appendix A of the drinking water directive 

Germany 0.5 mg/l6 The water that leaves the water treatment facility 

must not exceed Nitrite concentrations of 0.1 mg/l 

Table 7: Drinking water standards from the WHO, EPA, EU and Germany for Nitrite 

Derivation of guidelines for Nitrite contamination of drinking water are usually based on 

calculation of uptake per day per kg. 

Extract from the WHO Drinking water guideline: 

The guideline for Nitrite of 3 mg/l as Nitrite is based on human data showing that doses of Nitrite 

that cause methaemoglobinaemia in infants range from 0.4 to more than 200 mg/kg of body 

weight. By applying the lowest level of the range (0.4 mg/kg of body weight), a body weight 

 of 5 kg for an infant and a drinking-water consumption of 0.75 litre, a guideline value of 3 mg/l 

(rounded figure) can be derived (WHO/SDE/WSH/07.01/16).

 

3

 WHO/SDE/WSH/07.01/16 

4 http://www.epa.gov/OGWDW/contaminants/dw_contamfs/nitrates.html 5

 COUNCIL DIRECTIVE 98/83/EC 6

 Trinkwasserverordnung 2001, chemische Parameter II 
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6 RISK ASSESSMENT

As per definition ìriskî is determined by the equation 

Risk = Probability of occurrence * extent of loss/impact 

In the following the potential risks caused by the operation of the AquaTriComb ballast water 

treatment system technology as to the safety of the ship and to human health will be assessed. 

This will be carried out by means of estimating the probability of occurrence of hazardous 

situations multiplied with the estimations on the extent of losses and/or scale of impact caused by 

such hazardous scenarios. 

By definition of ìprototypingî this risk assessment has to be a probabilistic approach rather than 

a deterministically based risk assessment. This, in turn, may result in the absence of data-base 

secured figures. In case of such lack of data-based figures a prescriptive approach will be 

applied. 

6.1 Risk to safety of ship 

6.1.1 Ship integrity and the BWTS 

The AquaTriComb plant will be installed in line after the shipís ballast water pump(s). Inlet 

and outlet piping are equipped with by-pass-valves and shut-off safety valves (Figure 1). The 

valves are fitted with flanges and will be equipped with electrically driven, and manual actuators. 

If, for certain reasons, the BWTS operations have to be interrupted (service, maintenance, etc.) 

the plant will be bypassed by means of the bypass-valves and closing of the safety valves. 

This design does not interfere with the shipís integrity. 

Although electrical load calculations on larger versions of the plant have not been finalized yet, 

the probability that the energy demand would interfere with the onboard power supply, that is, 

the auxiliary diesel-generator sets, is rather low. 

With regard to the additional weight the prototype version is at approximately one point six (1.6) 

tons at 250 m3/h volume flow rate. A slightly flattened linear increase is expected for the larger 

versions, for example the 2,000 m3/h version would be at approximately 10 to 12 tons. 

This weight equals half the gross weight of a loaded twenty-foot standard container (20' container 

maximal gross weight equals 24 tons). Therefore, also the additional weight of the BWTS would 

not impact the integrity of the ship. 

6.1.2 Corrosion 

The AquaTriComb technology is characterized by the absence of any Preparations or 

aggressive additives or generated substances. Therefore, no corrosion supporting, or corrosion 

stimulating effects are connected to the technology. 

The effects of acoustic cavitation, which are generated by the ultrasonic oscillation, are strictly 

restricted to the interior of the MicroSintFilter (MSF) modules, respectively. Transfer of acoustic 

cavitation is system-dependent excluded, and piping or other components of the ship are not 

effected. 
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All the internal components of the AquaTriComb BWTS are designed and construed to match 

the effects of acoustic cavitation. 

6.1.3 Fire and explosion 

The electrical and electronic parts of the AquaTriComb BWTS are intrinsically safe. There is 

no risk of fire or explosion associated with the system. 

6.1.4 Noise and vibration 

The noise level generated by the AquaTriComb BWTS is far below the permissible average 

noise level at the work place of 85 decibel (A), according to EC guidelines 2002/44/EG 

and 2003/10/EG (BGBl 2007). 

Vibration level caused by the ultrasonic oscillation is rather low and noticeable only in direct 

contact with the MSF modules and the UV-reactor (hand touch). 

In addition, the plant will be installed on vibration mounts for the protection of the plant itself 

and to reduce in-water noise emissions to a minimum. 

6.1.5 Conclusion: risks to safety of ship 

The risks to the safety of the ship, caused by the installation and operation of the BWTS 

AquaTriComb, which is defined by the probability of the occurrence of a dangerous situation 

originated by the plant and the extent of impact, is not measurable by means of non existence. 

This covers the shipís integrity, corrosion, fire and explosion as well as noise and vibrations. 

If the ship itself makes for a dangerous scenario like fire, explosion, structural damage or loss, 

etc., the risks originated by the BWTS remain at zero as intrinsic safety is maintained and power 

shut-off is most probable. 

6.2 Risks to human health 

The AquaTriComb technology exclusively applies non-hazardous physical means of ballast 

water treatment which pose no risks to human health, that is: 

- Ultraviolet radiation (UV); and 

- Ultrasonic oscillation (US). 

The application of UV and US, however, generates physical active processes, explicitly photons 

and cavitation bubbles, which in turn could result in OH radicals (Relevant Chemical) and 

by-products (Other Chemical). 

The generation of OH radicals and by-products are confined to the feasible minimum by means 

of the application of exclusively UV-C radiation at 254 nm wavelength. Also, by the application 

of US-oscillation at a low frequency for a very limited time period of less than one (1) second 

only the size of the cavitation bubbles is as small as possible, and the effect of OH radical 

generating physical sonoluminescence is reduced to the most practicable minimum. 
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Therefore, OH is considered not resident in the treated ballast water and causes no harm to 

human health or to the environment. 

In case OH radical related eco-toxicological by-products (Other Chemicals) are generated this 

will be on a level below the LoQ of the analytical methods. Thus by-products were not detectable 

in ballast water treated by AquaTriCombô BWTS. In addition, occurrence of UV radiation and 

Ultrasound are limited to the hermetically enclosed MSF and UV-reactor, and risks to human 

health can be excluded. 

6.2.1 Human exposure assessment 

Because exclusively physical means of ballast water treatment are applied with the 

AquaTriComb technology the exposure assessment focuses on potential exposure as to: 

- UV-radiation; 

- Ultrasound oscillation; and 

- OH and by-products. 

 Potential exposure to Ultraviolet (UV) radiation: Inside the hermetically enclosed UV-reactor 

UV-C-radiation is generated by high performance, low-pressure mercury germicidal lamps with a 

filtered and selected wavelength of approximately 253.7 nm. 

The tube casing of the AquaTriComb UV-reactor and the top and bottom plating is made of 

stainless steel (V4A). Top plating cable fairleads are welded and additionally covered by 

aluminium coverage. All welding and bolt connection are according to respective technical 

norms and standards and performed by accredited and certified workmanship. Therefore, the 

probability of regular and/or accidental emission of UV-radiation equates zero. 

 Potential exposure to Ultrasound (US) oscillation: The ultrasonic tube oscillators are located 

along the centre line inside the MicroSintFilter (MSF) modules and inside the UV-reactor. 

Oscillation at low frequency permanently preventing particle accumulation in the MSF modules, 

and des-agglomeration of organic particles, detritus, colony-forming algae and other 

agglomerates (bio film) at the surface of the mercury germicidal lamps. 

The MSF modules are identical in design and construction as the UV-reactor, which results in no 

release of ultrasound and no impact to human health. 

 Potential exposure to OH and by-products: As stated above, the concentration of OH and 

by-products would be on such a low level that risks to human health can be excluded. Therefore, 

risks to human health by means of exposure to Relevant or Other Chemicals can be excluded. 

In applying the Margin of Safety (MOS) or Margin of Exposure (MOE) approach, the equation 

would consequently result in No Observed Adverse Effect Level (NOAEL). 
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6.2.1.1 Hazard identification 

In regular operation mode of the AquaTriComb BWTS no hazards to human health can be 

identified: 

- No persons are exposed to UV radiation; 

- Low-level casing vibration caused by US oscillation inside MSF modules does not 

pose any hazard; and 

- No contact with non-hazardous concentration of potential Relevant or Other 

Chemicals. 

 In service and maintenance (S&M) mode hazards are limited to illegal and/or intentional risk 

exposure: 

- Non switch-off of energy supply before S&M works with the risk to exposure to 

UV-C radiation; and 

- Operational procedures, alert signing and emergency shut-off device will prevent such 

scenario (to be integrated into shipboard SMS-manual7

). 

 In incidental/accidental mode such as shipboard fire, explosion, black-out, structural loss, etc. 

most probably energy supply to BWTS will be cut-off anyhow and/or BWTS will have 

malfunction. 

6.2.1.2 Exposure assessment 

Regular operation and maintenance procedures (O&M) on board ship include inspection of sea 

chest and sea water/ballast water piping and pumps, and related services. For such action the 

BWTS will be shut-down, thus no exposure to UV-radiation or chemicals will appear. This also 

counts for dry docking and/or annual classification services in dock/alongside the pier. 

Due to high quality plant components and materials service and maintenance intervals of the 

BWTS are extremely low. The exchange of the ultrasonic tube oscillators are calculated after a 

minimum of approximately 16,000 operational hours, the exchange of the low-pressure mercury 

germicidal lamps are calculated after circa 12,000 operational hours. 

As no Preparations are utilized or generated by the AquaTriComb BWTS normal and good 

workmanship practice is to be applied by the personnel involved (gloves and mask). 

No additional or special precaution measures are recommended or necessary. 

6.2.2 Conclusion: Potential Human Health Risks 

Normal operation and maintenance (O&M) procedures of the AquaTriComb BWTS do not 

pose any risks to human health, nor acute, neither mid/long-term exposure situations are 

realistically probable. This statement covers all population groups including crew, service 

 

7

 SMS means Safety Management System according to the ISM-Code (ISM 2002). 
MEPC 59/2/8 

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technicians, passengers and personnel, public and port persons, or consumers of seafood and 

persons at the coastline. 

The probability of incidental and/or accidental health risks caused by the AquaTriComb BWTS 

are limited to catastrophic or worst-case scenarios, although almost implausible. 

The absence of any Preparations reduces such risks to shipboard fire, explosion, structural 

damage/loss and similar casualties. In occurrence of such catastrophic events it is assumed that 

the power supply to the BWTS is cut-off anyway, resulting in non-performance of UV-radiation 

and/or US-oscillation, and associated processes. 

From the Risk Assessment carried out are no identifiable risks associated to the ship, its 

personnel or other persons and/or parties concerned, which are originated by the installation and 

operation of the AquaTriComb ballast water treatment system. 

This is mainly due to the fact that the BWTS does not introduce any Preparations, Active 

Substances or Relevant Chemicals but the technology is a purely physical treatment technology. 

Further, the design and construction do not interfere with the vesselís integrity, and high-end 

components and materials guarantee reliable and sound performance. 

6.3 Risks to the aquatic environment 

6.3.1 Magnitude of Hazard from the Ballast water treatment process 

In Table 8 is exemplary shown the PNEC (Predicted No Effect Concentrations) for Nitrite value 

in water. 

Substance 

Substance class 

PNEC Medium Reference 

Nitrite Inorganic nutrient 10 μg/l Water Bursch 2003 

Table 8: Predicted No Effect Concentrations (PNEC) for Nitrite (Bursch 2003). 

6.3.2 Probability of exposure 

Exposure to Other Chemicals could occur through the emitted treated ballast water. According 

to the chemical analyses, none of the Other Chemicals, discussed in this report, are produced 

significantly above LoQ. It can also be concluded from the chemical data directly that the Nitrite 

values shown by statistic evaluation are not caused by the treatment process. 

6.3.3 Assessment of environmental risk 

On the basis of the results of analysis of several theoretical possible by-products at this stage of 

the assessment it can be concluded that there is no indication for an environmental risk from this 

treatment process. 

6.3.4 Conclusion on risk to human health 

Exposure of humans to the active substances is not possible. Exposure to potentially Other 

Substances in the treated ballast water would theoretically be possible but with low probability. 

Effects are highly unlikely due to the low aquatic toxicity. 
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Toxic effects through volatile substances such as chloroform would theoretically be possible and 

there is indication of risk to human health from any substances produced in the process at this 

stage. 

7 ASSESSMENT REPORT (G9: 4.3) 

7.1 Overview of data and endpoints 

During the AquaTriComb-process aquatic organisms will be affected by photons and cavitation 

bubbles. Both are short lived and their presence is restricted to the duration of the UV and 

US application, locally to the treatment reactor. 

Exposure to the aquatic environment from substances termed Other Chemicals, which can be 

produced indirectly through photons or cavitation bubbles, could occur after discharge of the 

treated ballast water. 

As shown by chemical analysis of water samples before and after ballast water treatment, 

concentrations of all observed substances were below the LoQ. Therefore, no indication of 

release of harmful substances, resulting in an increase of environmental concentrations could be 

observed. Except for Nitrite, which data above the LoQ showed a high variability of 

concentrations. Statistical analysis indicate that data before and after treatment are not 

significantly different. Therefore, the treatment process is not responsible for the observed Nitrite 

values. 

As there is no indication for the release of harmful substances, the actual potential for 

bioaccumulation is considered to be very low. Neither sediment toxicity, nor bioconcentration or 

magnification effects, including secondary poisoning are considered to be of concern. 

From the Risk Assessment carried out are no identifiable risks associated to the ship, its 

personnel or other persons and/or parties concerned, which are originated by the installation and 

operation of the AquaTriComb ballast water treatment system. 

On the basis of the results of analysis of several theoretical possible by-products and the risk 

assessment it can be concluded that there is no indication for a risk to the aquatic environment 

and/or humans based on the treatment process of the AquaTriComb BWTS. 

7.2 Test report data quality 

References used for this approval comprise Risk Assessment studies from Euro Chlor, the 

European Commission, WHO, and US EPA, which critically evaluated their data basis with 

regard to accredition of laboratories, standardization of test systems and documentation of 

results. 

Furthermore, peer reviewed articles were used to gain detailed information. The PAN Pesticide 

database proved to be very helpful. All of its information is backed up by rigorous scientific 

studies and most of the data are taken from official sources of weight-of-the-evidence-type 

evaluations when they are available. For more information of data accuracy of the data base: 

http://www.pesticideinfo.org/Docs/data.html#AccuracyofData
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8 REFERENCE DOCUMENTS 

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Internet citations 

BGBl (2001): Verordnung zur Novellierung der Trinkwasserverordnung, 2001, 

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BGBl (2007): www.bgblportal.de/BGBL/bgbl1f/bgbl107s0261.pdf, cited 24/09/08. 

DVGW (2001): http://www.dvgw.de/en/english-pages/drinking-water/ cited 24/09/08. 

EPA: http://www.epa.gov/OGWDW/contaminants/dw_contamfs/nitrates.html

ISM 2002: www.imo.org/HumanElement/mainframe.asp?topic_id=287, cited 24/09/08 

Pesticide Action Network (PAN) Pesticide Database: http://www.pesticideinfo.org/, cited 

27/09/08 

Trinkwasserverordnung: 

http://www.dvgw.de/wasser/recht-trinkwasserverordnung/trinkwasserverordnung/ 

cited 06/11/08 

USEPA (2006) http: //www.epa.gov/safewater/disinfection/lt2/compliance.html, cited 27/08/08 

Umweltbundesamt (2008b) http: //www.umweltbundesamt.de/verkehr/verkehrstraeg/seeschiff/ 

umweltschutz-seeschiffe/ ballastwasssermanagement.htm, cited 03/09/08 

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