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

kindly asked to bring their copies to meetings and not to request additional copies.

I:\MEPC\59\2-5.doc 

INTERNATIONAL MARITIME ORGANIZATION

IMO 

E

MARINE ENVIRONMENT PROTECTION 

COMMITTEE 

59th session 

Agenda item 2 

MEPC 59/2/5

 11 December 2008

 Original: ENGLISH

HARMFUL AQUATIC ORGANISMS IN BALLAST WATER 

Application for Final Approval of the Hitachi Ballast Water Purification 

System (ClearBallast) 

Submitted by Japan 

SUMMARY

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

application for Final Approval of the Hitachi Ballast Water 

Purification System (ClearBallast) in accordance with the “Procedure 

for approval of ballast water management systems that make use of 

Active Substances (G9)” 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 7 

Related documents: BWM/CONF/36; MEPC 57/2, MEPC 57/2/2, 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 Ships’ 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 Procedure for approval of ballast water management systems that make use of Active 

Substances (G9) stipulates the information that should be included into a proposal for approval 

and provisions for risk characterization and analysis. According to section 6 of Procedure (G9), 

the Organization should evaluate the information provided in the application. 

3 According to BWM.2/Circ.15, a document on the proposal for approval containing all the 

non-confidential data related to the respective ballast water management systems that make use 

of Active Substances needs to be submitted to MEPC 59. 
MEPC 59/2/5 - 2 - 

I:\MEPC\59\2-5.doc 

4 This document contains non-confidential information related to the application for 

Final Approval of the Hitachi Ballast Water Purification System (ClearBallast) in accordance 

with the “Procedure for approval of ballast water management systems that make use of Active 

Substances (G9)” adopted by resolution MEPC.169(57). The system is developed by Hitachi 

Plant Technologies, Ltd., using enhanced water treatment technology based on coagulation 

magnetic separation method. 

5 The competent authority in Japan has verified the application dossier and believes that it 

satisfies the data requirements of Procedure (G9). 

6 Japan therefore submits the non-confidential part of the manufacturer’s application 

dossier, as set out in the annex to this document, to the Organization for evaluation according to 

Procedure (G9). The complete dossier will be made available to the experts of 

the GESAMP-BWWG with the understanding of confidential treatment. 

Action requested of the Committee 

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

*** 
MEPC 59/2/5 

I:\MEPC\59\2-5.doc 

ANNEX 

NON-CONFIDENTIAL INFORMATION ON THE HITACHI BALLAST WATER 

PURIFICATION SYSTEM (JAPAN) 

1 Introduction 

1.1 Features of the Hitachi Ballast Water Purification System 

1.2 Test results 

1.3 Glossary 

2 Summary of the recommendations of the GESAMP-BWWG in the review of 

proposal for Basic Approval and the applicant’s responses 

3 Outline of Hitachi Ballast Water Purification System 

3.1 Additive concentration of coagulant chemicals 

3.2 Purification process 

3.3 Purification system 

3.4 System specifications 

3.5 General specifications of electrical devices 

3.6 Constituents machines 

3.7 Operation procedure 

3.8 Actions in case of problems or emergency 

3.9 Scale up 

3.10 Quality assurance 

3.11 Measures to reduce risks to humans and ships 

3.12 Maintenance 

3.13 Supply and storage of chemicals 

4 Assessment of treated water 

4.1 Water sampling 

4.2 Quality of collected floc 

5 Ecotoxicity test of treated ballast water 

5.1 Acute toxicity test 

5.2 Chronic toxicity test 

5.3 Study on effects of treated water under higher concentration of Active Substances 

6 Risk characterization and risk assessment 

6.1 Summary of critical information of substances 

6.2 Risk assessment with regard to ship safety 

6.3 Risk to human health 

6.4 Risk assessment on aquatic organisms 

6.5 Establish the maximum allowable discharge concentration 

6.6 Conclusion on risk to the aquatic environment 
MEPC 59/2/5 

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1 Introduction 

Hitachi Ballast Water Purification System (ClearBallast) was granted Basic Approval by the 

Marine Environment Protection Committee at its 57th session in April 2008. This application 

dossier is for Final Approval in accordance with the Procedure for approval of ballast water 

management systems that make use of Active Substances (G9). 

This system employs conventional drinking water purification technology to form flocs using 

triiron tetraoxide, PAC, PASA and the like to coagulate organisms and other suspended matters 

in ballast water. Strong magnetic force is used to quickly remove flocs, thereby making it 

unnecessary to use biocides. The chemicals used in this system are the same as those used in 

drinking water purification process, and have been extensively cited in literatures relating to 

human health and the environment (including World Health Organization (WHO) guidelines), so 

there is plenty of evidence to show that they are safe. 

This application is prepared by Hitachi Plant Technologies Ltd. although the application of 

Basic Approval was prepared by joint name of Hitachi Ltd. and Hitachi Plant Technologies Ltd. 

1.1 Features of the Hitachi Ballast Water Purification System 

The system coagulates target organisms and other suspended materials using a coagulating agent 

during the ballast water intake, and cleans the ballast water by efficiently separating and 

removing aquatic organisms through a combination of magnetic separation and filter separation 

techniques. 

1.2 Test results 

From September 2006 through March 2008, tests using a prototype test set-up (treatment rated 

capacity of 50 m3/h) in Tokyo Bay are performed. After the Basic Approval granted, from April 

to October 2008, shipboard testing of this system with a treatment rated capacity of 50 m3/h 

mounted on board an LPG carrier belonging to Yuyo Steamship Co., Ltd. and built by Mitsubishi 

Heavy Industries, Ltd., was performed. From April of the same year, land-based tests were also 

performed in Tokyo Bay, using a land-based test set-up (treatment rated capacity of 200 m3

/h). 

Figure 1-1 shows the onboard test set-up and Figure 1-2 shows the land-based test set-up. 
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Figure 1-1 − Overview of onboard test set-up 

Figure 1-2 − Overview of land-based test set-up 

1.3 Glossary 

Chemical Injector: A device to inject chemicals (triiron tetraoxide, PAC, or PASA), which is 

a part of the Hitachi Ballast Water Purification System. 

Coagulator: A device to transform chemicals into flocs containing SS, plankton, bacteria, and 

so on, which is a part of the Hitachi Ballast Water Purification System. 

Collected Flocs Storage Tank: A tank for storing the removed flocs containing chemicals, 

SS (suspended solids), plankton, bacteria, and so on, which is a part of the Hitachi Ballast Water 

Purification System. 

Filter Separator: A device which removes flocs from the ballast water using a rotating filter 

drum, as a part of the Hitachi Ballast Water Purification System. 

Floc: Gelatinous matter made up of fine particles such as a suspension colloid in water 

(suspended solids) formed by an inorganic coagulant or high-polymer coagulant. 
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Inorganic Coagulant: A chemical containing metallic ions of aluminium or iron that forms a 

larger floc of fine particles dispersed in water such as a suspension colloid by neutralizing the 

charge on their surfaces. 

Magnetic Disk: A component of the magnetic separator. A disk in which magnets (permanent 

magnets) are embedded. 

Magnetic Disk Array: A component of the magnetic separator. An assembly consisting of several 

magnetic disks arranged coaxially. 

Magnetic Separator: A device which removes flocs from the ballast water using a magnetic disk 

array, as a part of the Hitachi Ballast Water Purification System. 

PAC: Poly Aluminium Chloride. An inorganic coagulant consisting of poly aluminium chloride 

and referring to basic aluminium chloride. 

PASA: Poly Acrylamide Sodium Acrylate. A crosslinking chemical consisting of high molecular 

weight polymer particles with a negatively charged surface, which forms a coagulation of fine 

particles suspended in water such as a suspension colloid. It is a kind of Anionic High-Polymer 

Coagulant. 

2 Summary of the recommendations of the GESAMP-BWWG in the review of 

proposal for Basic Approval and the applicant’s responses 

The recommendations of the GESAMP-BWWG in the review report of the application for Basic 

Approval, which the applicant should pay careful attention at the application for Final Approval 

(MEPC 57/2, annex 5, Summary 0 and Conclusions 9), and the applicant’s responses to them are 

summarized as follows; 

Summary 0.4.1/Conclusions 9.4.1 

An adequate quality assurance programme needs to be developed for the entire system (including 

the quality of PASA at industrial production). 

Hitachi Plant Technologies, Ltd. will assume control and responsibility for the quality of the 

entire system (design, construction and maintenance of equipment main unit, and supply of 

consumable chemicals). 

Summary 0.4.2/Conclusions 9.4.2 

For Final Approval, the human health risks of the system will be evaluated by the 

GESAMP-BWWG on the basis of its individual unit operations, i.e. each component of the system 

requiring operator attention. The manufacturer is therefore requested to describe separately the 

potential human health risks associated with each major component of the system and to describe 

the measures necessary to prevent human exposure for each such component. In particular, the 

methods employed for the collection, treatment and disposal of floc and their potential for 

occupational exposure need to be described. Additionally, the recommended risk reduction 

measures need clear explanation and documentation, e.g., for each procedure such as floc 

collection, dewatering, drying, incineration, sterilization, storage and disposal in whatever form. 
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In the assessment of crew exposure, the risks of each component of the system associated with 

the unit operations have been identified and clearly indicated. To eliminate the material risks, the 

equipment settings have been reviewed from the viewpoint of crew safety, and statements 

regarding the use of suitable protective gear and safety gear have been added. On the basis of this 

review, the risks associated with operations for the collection, storage and disposal of flocs have 

been identified, and measures to reduce these risks are considered and described. 

Summary 0.4.3/Conclusions 9.4.5 

The storage and handling of the three Active Substances on board needs to be carefully 

controlled and the proposed safety measures adequately documented, particularly bearing in 

mind the corrosive properties of poly aluminium chloride. 

The physical and chemical states of the three Active Substances are specified, the risks they pose 

to the ship’s hull are characterized and assessed, and then the guidelines for their storage and 

handling are proposed. In particular, with regard to PAC which is slightly corrosive to metals, 

measures are in place for the prevention and avoidance of hull corrosion by using resin coatings 

at surfaces in contact with this material. 

Summary 0.4.4/Conclusions 9.4.6 

One major human health issue regarding the Active Substances relates to the residual 

acrylamide monomer contained in the polyacrylamide, which has a range of associated human 

health hazards and which, in parallel to best practices in drinking water purification, needs to be 

maintained at appropriately low concentrations. The quality of the polyacrylamide Active 

Substance needs to be strictly controlled and included in the QA programme to ensure 

acceptably low concentrations of acrylamide monomer. 

The maximum allowable discharge concentration is based on the collected data on the hazards to 

human health and aquatic organisms by residual acrylamide monomers in polyacrylamide. 

Polyacrylamide of sufficient quality to satisfy these design concentrations is supplied by Hitachi 

Plant Technologies, Ltd. 

Summary 0.4.5/Conclusions 9.4.7 

The BWM system appears from the technical description to be partly open, allowing for possible 

occupational exposure to the crew to system processes and waste. This is a potential weakness of 

the system that remains to be adequately addressed. 

The constituent equipment of this system has a fully closed structure in order to prevent the 

leakage or escape of liquid or dust particles. With regard to the possibility of exposure to 

crewmembers while carrying out their work, the assessment and measures are included in a 

response to the points raised in Summary 0.4.2/Conclusions 9.4.2. 

Summary 0.4.6/Conclusions 9.4.8 

Human health issues related to the potential concentration of pathogens in the flocs need to be 

examined and assessed in detail. The flocs could, under heavily polluted intake conditions, have 

the potential to form a biohazard. 
MEPC 59/2/5 

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Considering the possibility of pathogenic bacteria contained in the intake water, safety measures 

for human health have been established against the potential risks of pathogenic bacteria 

exposure risks to ship crew. 

To promote careful handling of collected flocs in preparation of bacteria captured in floc, labels 

are affixed to the collected flocs storage tanks and carrying containers recommending the use of 

protective gear and promoting care with regard to pathogenic bacteria in the floc storage and 

landing processes, and stating that the storage tanks and transportation containers are to be kept 

closed. 

Summary 0.4.7/Conclusions 9.4.9 

Adequate separation of the flocs from the treated water is crucial to the successful operation for 

the system. When scaling up to larger treatment capacities, this aspect must be addressed by the 

applicant, to ensure the human and environmental risks of the treated ballast water remains 

acceptable. 

When the equipment is scaled up, its processing performance does not change and there is no risk 

on scaling up this system. In addition, the human and environmental risks via treated ballast 

water and operations relating to the system remain acceptable with appropriate measures. This is 

not only backed up by theory, but has also been clearly demonstrated from the results of 

comparative verification tests of prototype test set-up and land-based test set-up. 

Summary 0.4.8/Conclusions 9.4.10 

The positioning and operation of the proposed pre-filtration, as well as post-filtration and its 

residue feedback system must be better described and documented. The procedures and 

processes for routine system maintenance, emergency procedures, filter and sludge conveyor 

cleaning, and the treatment and handling of the sludge must be defined and detailed. 

The flow paths of water and flocs including the installation point of the filter separator unit, the 

flow of treated water, and the flow of filter residues trapped in the filter separator unit have been 

explicitly indicated. Daily and periodic maintenance, recovery procedures for error and 

emergency situations, cleaning of the filter unit of filter separator, and cleaning of floc collection 

mechanism of magnetic separator have been expressed clearly in the corresponding descriptions 

concerns regarding. The treatment and handling of collected flocs have been addressed the 

concerns raised in Summary 0.4.2/Conclusions 9.4.2. 

Summary 0.4.9/Conclusions 9.4.11 

The risk to the marine environment from the residual Active Substances must be assessed. 

Concentrations of heavy metals, aluminium, iron, acrylamide monomer, VOCs, and faecal 

coliforms must be measured in the intake water, collected sludge and the discharged ballast 

water from the representative ballast waters associated with testing under G8. The 

environmental risks of discharging polyacrylamide, a non-biodegradable polymer to shore and 

any subsequent disposal restrictions must be assessed. 

The results of analysing the content of toxic heavy metals, aluminium, iron, acrylamide 

monomers, VOCs and faecal coliforms in treated ballast water and flocs have been presented. 

The potential risks and hazards have been assessed on the basis of those results. The method of 
MEPC 59/2/5 

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measuring polyacrylamide in the treated water and influent has been developed, and the results of 

this chemical analysis have been reported. 

Summary 0.4.10/Conclusions 9.4.12 

Disposal of the collected sludge to shore-based waste reception facilities should be according to 

the relevant IMO regulations. The availability of suitable harbour reception facilities needs to be 

considered. 

Concerns regarding the disposal and handling of collected flocs have addressed the concerns 

raised in Summary 0.4.2/Conclusions 9.4.2. The process of unloading and disposing flocs should 

be performed in accordance with the domestic law and the MARPOL Convention. 

Summary 0.4.11/Conclusions 9.4.14/ENVIRONMENTAL RISK ASSESSMENT 8.1.2 

Additional toxicity testing of the treated Ballast Water should be performed using an appropriate 

range of conditions. (ENVIRONMENTAL RISK ASSESSMENT 8.1.2: Furthermore, the group 

recommends that the applicant should conduct the additional toxicity testing under higher 

concentration of PAC and PASA at the laboratory scale, e.g., using samples taken before the post 

filtering.) 

To address this recommendation, a couple of experiments have been carried out and the results 

have been described in section 5.3 entitled “Study on effects of treated water under high 

concentration of Active Substances”. The upper limit of the concentration of added chemicals for 

toxicity tests have been determined on the basis of tests in which the chemicals were added at 

twice and three times the standard quantities in order to study the flocculating performance. 

Consequently the upper limit of chemicals concentration for adequate coagulation performance 

has been detected as approximately twice the standard amounts. From this result, the maximum 

amount of chemicals to be added under the condition of higher concentration of chemicals was 

taken to be twice the standard amount. The results of toxicity tests performed using this effluent 

are shown. 

In addition, to evaluate the effect of seawater with a higher concentration of the residual Active 

Substances on marine organisms, ecotoxicity tests were carried out using seawater containing 

flocs generated by this system. The test results indicate that flocs in such water at the rated 

condition of chemicals had no effect on aquatic organisms such as zooplankton and fish. These 

experiments were conducted by a GLP compliant laboratory. 

Summary 0.4.12/Conclusions 9.4.13 

The risk assessment carried out by the applicant in the submission cannot be accepted by the 

GESAMP-BWWG, as it is unclear how the risk assessment was performed and how both the PEC 

and PNEC of concentration for Aluminium-ions and other relevant chemicals have been 

established. The Group therefore recommends to the MEPC to request the applicant to prepare a 

revised risk assessment for consideration in any application for Final Approval. 

In addition to the hazard data at the time of the application for Basic Approval, other reference, 

research and academic reports have been surveyed, subsequently risk assessment has been 

performed with reference to typical risk assessments report. 
MEPC 59/2/5 

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Summary 0.4.13/Conclusions 9.4.15 

The maximum allowable discharge concentration should be set against the parameters that can 

be measured at such low levels. According to the applicant, it is difficult to measure the amount 

of PASA directly, if its concentration in water is low. This situation is considered to be 

unsatisfactory by the Group and an acceptable analytical method should be developed for 

confirming the maximum allowable discharge concentration for relevant parameters. 

The PASA analysis method and measurement results have been developed according to 

the points raised in Summary 0.4.9/Conclusions 9.4.11. On the basis of the analytical results and 

other studies, the maximum allowable discharge concentration has been established with 

considering the risk assessment in accordance with the points raised in 

Summary 0.4.12/Conclusions 9.4.13. 

3 Outline of Hitachi Ballast Water Purification System 

3.1 Additive concentration of coagulant chemicals 

In the standard operation of the ballast water purification process using the coagulation magnetic 

separation method, the amounts of chemicals added are 5 mg/L of PAC (as Al), 30 mg/L of 

triiron tetraoxide (Fe3O4) and 1 mg/L of PASA. PAC and PASA are widely used in drinking 

water purification plants so the safety of these chemicals has been confirmed. Triiron tetraoxide, 

whose composition is Fe3O4, is a natural resource that exists broadly in nature. Table 3-1 shows 

the rated concentration of each chemical used in the coagulation magnetic separation method. 

Table 3-1 − Rated concentration of chemicals 

Additive agent Additive concentration 

(mg/L) 

Triiron tetraoxide 30 

PAC 5 (as Al) 

PASA 1 

3.2 Purification process 

Figure 3-1 schematically shows the ballast water purification process in this system. First, triiron 

tetraoxide and PAC are added to intake water containing plankton, bacteria, and SS. Next, PASA 

is added to form flocs of about 1 mm in diameter. These flocs are then separated from the ballast 

water using permanent magnets. Finally, any flocs that were not removed by the magnetic 

separation are removed by filtering to produce purified water. 

Magnetic separation is appropriate for large-scale continuous high-speed treatment because 

it is fast, highly efficient separation using magnetic force to remove flocs and enables compact 

design, which satisfies the requirement for ballast water management systems. 

The SS concentration of the water treated by magnetic separation is low. Consequently, 

the SS concentration of the water after magnetic separation flowing into the filter is also low, 

which reduces the load on the filter and enables high-speed, high-efficiency filtering. The filter is 

continuously washed and revitalized during the filtering proceeds. The residue from filter 

washing is returned to the ballast feed pipes before the first chemical (triiron tetraoxide) injection 

point through a filter washing residue tank and treated together with untreated water to maintain 

clear water processing. 
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With this system, the ballast water can be purified either during storage in the ballast tank, during 

intake, or during discharge. Purification during intake is the most effective way to ensure that a 

minimal amount of organisms and SS enter the ballast tanks and thus reduces sediment build-up 

in the tanks. Therefore, this application focuses on the system components and operations for 

purification during intake. 

Hitachi ballast water purification system 

Magnetic 

seprator

Coagulator

Filter 

separator

Filter residue from filter 

 washing 

(to be treated with seawater)

Collected flocs 

storage tank 

Treated water 

(to ballast tank)

Ballast 

pump 

Ballast water 

PASA 

Landing and waste 

treatment, etc.

Flash 

mixer 

Flocculator

Triiron tetraoxide 

PAC 

Residue tank

from filter 

washing 

Chemical injectors

Figure 3-1 – Purification process 

3.3 Purification system 

This system consists of chemical injectors, a coagulator, a magnetic separator, a filter separator, a 

tank for storing collected flocs, a filter washing residue tank and a control system. 

The operation and monitoring of this system is automated, so no operators or crew are required. 

Some manual operations are required for refilling the chemicals into the storage tank, unloading 

the collected flocs, and maintenance checks; these manual operations need to be performed every 

several weeks or years, depending on usage and water route. Figure 3-2 shows the diagram of 

this system. 
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Chemical injectors

Coagulator

Magnetic Separator Filter separator

To 

ballast 

tank

To collected flocs storage tank

From ballast pump

FIC

LvS

PLC Power supply

Local control panel

Compressed air

Operation panel

Central console room

Detection point

signal

Gravity 

or 

pump 

:Pump 

:Motor 

:Flow indicator controller 

:Level switch 

:Programable controller 

:Detection point

LvS

FIC

M

PLC

LvS LvS

filter w ashing 

residue tank 

(tem porarily used)

source 

Figure 3-2 – Purification process diagram 

3.4 System specifications 

3.4.1 Environment settings 

The environment settings of this system are shown below assuming that the system is installed in 

an engine room, a steering gear room or an upper deck. If the system is installed in a place such 

as an upper deck, which does not meet the conditions mentioned here, it is necessary to install the 

system in a closed casing with thermal insulation, ventilation, etc., to achieve the environment 

settings shown below. 

Environment settings Temperature: 0 to 50 degrees Celsius 

Humidity: less than 90 % 

Slant: less than 22.5 degrees 

3.4.2 Facilities line-up 

This section describes the facilities line-up (as of October, 2008) of the Hitachi Ballast Water 

Purification System “ClearBallast” as follows. 

Type1 Treatment rated capacity: 200 m3

/h 

Facility size: 20 ft bulk container 

Power consumption: 20 kW 

Type2 Treatment rated capacity: 400 m3/h 

Facility size: 40 ft bulk container 

Power consumption: 40 kW 

Type3 Treatment rated capacity: 800 m3

/h 

Facility size: 40 m2

 Foot Print*1) 

Power consumption: 60 kW 
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Type4 Treatment rated capacity: 1,200 m3

/h 

Facility size: 58 m2 Foot Print*1) 

Power consumption: 120 kW 

Type5 Treatment rated capacity: 1,600 m3/h 

Facility size: 77 m2 Foot Print*1) 

Power consumption: 130 kW 

*

1): This shows the installation area of this system. 

3.5 General specifications of electrical devices 

Table 3-2 lists the standard specification of electrical devices used in this system. 

Table 3-1 − General specifications of electrical devices 

Term Specification 

Class of insulation F or B 

Ingress protection IP22 or P44 

3.6 Constituents machines 

This section explains the main pieces of equipment. 

All equipment comes in a closed-structure, pressure resistant casing to prevent leakage and 

scattering of liquid and powder. Figure 3-3 shows the main equipment used in the land-based 

test set-up (treatment rated capacity of 200 m3/h) as an example. 

Flash mixer

Flocculator 

Magnetic separat

Filter separator

Control panel 

Ballast water 

Treated water 

Figure 3-2 − Overview of land-based test set-up and main constituent machines 
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3.7 Operation procedure 

Hitachi Ballast Water Purification System (ClearBallast) is automatically operated by the 

controlled, and no operator is required on site. An operator operates the control panel in the 

centre console room to issue a remote command for starting the equipment and monitors the 

operational status indicated on the control panel’s display during operation. If no problems occur, 

the operator is only required to issue a remote command for stopping the equipment. 

Figure 3-4 shows the operational procedures for the ballast water purifying system. These consist 

of “Set-up mode”, “Operational mode” and “Shutdown mode”. 

In “Set-up mode”, chemicals required for this system are prepared automatically and the system 

automatically checks that the devices operate normally. 

In “Operation mode”, the system starts and stops operation corresponding to ballast water pump 

operation. 

In “Shutdown mode”, upon receiving the stop command from the centre console room, the 

machines in this system are stopped automatically, the inside of the ballast water purification 

system (constituents machines) is cleaned, and preparations for the next operation are performed. 

Figure 3-4 – Schematic procedure of system operation 

3.8 Actions in case of problems or emergency 

3.8.1 Corrective actions 

Problems stated in this system are classified into three categories related to flow rate, water level 

(water height in tanks and casings) and equipment. These problems are detected by sensors 

which are controlled and monitored by the control system. If any problems are detected in this 

system by the sensor, the equipment is automatically controlled corresponding to its error level 

by the control system while a warning buzzer and indication lamp provides safety. 

After an error is detected and the equipment stops automatically, the operator should check the 

control panel’s display to identify the error and perform inspection and recovery work. Since the 

equipment is not automatically reset after an error is solved, the operator should issue a command 

to re-start operation after checking that the operation/control panel in the centre console room 

does not indicate any error. 

 Set-up mode

Operation mode

Shutdownmode

Preparation of chemicals

Operation and temporary stop

End stop and system washing
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3.8.2 Actions in case of blackout 

If a blackout occurs while the equipment is operating, the equipment stops operations, and 

automatically controlled valves are reset to starting position. The intake valve automatically 

closes when the power supply stops, preventing ballast water leakage from pipe or others. 

Since the equipment does not automatically reset after the power supply is restored, the operator 

should issue the start command to restart operations after checking that the status display in the 

centre control room or on the local control panel does not indicate any error. And since this 

system is equipped with interlocking of start conditions, a restart command does not work unless 

a safety check has been conducted to prevent human errors. 

3.8.3 Actions in case of emergency 

Operation of the equipments in this Hitachi Ballast Water Purification System can be stopped 

urgently by using the emergency stop switch on the control panel in the centre control room or 

local. When this is done, operations stop and the intake valve closes, so ballast water does not 

leak out. Warning buzzers and indicating lamps in the centre console room or on the local control 

panel indicate an emergency stop to the operator. 

3.9 Scale up 

The performance of this system is assured by keeping the water flow velocity in piping and 

constituents machines (coagulator, magnetic separator and filter separator) within a certain range, 

and so can be scaled up while keeping the rated flow velocity. This method of scaling up is the 

same as general centrifugal pumps and piping, and so poses no specific risks. 

3.10 Quality assurance 

This system is produced in a designated factory (ISO9001 certified factory) of Hitachi Plant 

Technologies Ltd., which has a strict quality control programme, and meets the required quality 

by the Guidelines for approval of Ballast Water Management Systems (G8). The factory controls 

quality according to the quality control programme in the respective stages of production. 

3.11 Measures to reduce risks to humans and ships 

The measures to reduce risks in the Hitachi Ballast Water Purification System are described 

below. 

3.11.1 Measures to prevent chemical leakage 

Prevention of chemical leakage is important to protect the safety of humans and the ships. The 

following preventive measures are taken in this system to substantially reduce the risk of 

chemical leakage. 

(1) Measures for preventing leakage from the chemical storage tank 

Plastics such as PE (polyethylene) are used for the wetted surface of the storage tank and the 

injection line of PAC, which is slightly corrosive to metals, to avoid the risk of leakage caused by 

corrosion. The closed structure of the respective chemical tanks reduces the risks of chemical
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leakage and scattering. Each chemical storage tank is placed in coamings with level sensors to 

detect chemical leakage and alert crew. The leaked chemicals are sent to the filter washing 

residue tank, and are treated appropriately. 

(2) Measures for preventing liquid leakage in the chemical injection line 

The causes of chemical leakage from the chemical injection line are corrosion, an unusual 

pressure rise in the piping and degradation of packing gland of flange junction, so special care is 

taken for the materials and structure of the chemical injection line. The injection line is equipped 

with a pressure safety valve to safeguard against unusual pressure increase and the increased 

pressure, and the chemicals are returned to the chemical injection storage tank. Increased 

pressure is relieved in the chemical storage tank. Therefore, the possibility of chemical leakages 

from unusual pressure increases is eliminated. The packing gland on flange junction is checked 

and replaced periodically. 

3.11.2 Measures for preventing water leakage 

(1) Measures for preventing water leakage from the equipment 

The causes of water leakage are corrosion and equipment defect, so special care is taken for the 

painting and structure of the equipment and operation control at the time of any problems. 

(2) Measures for preventing water leakage from the piping 

The causes of water leakage from the piping are corrosion and unusual pressure rises in the 

piping, so special care is taken for surface treatment of the wetted surface and operation control 

in the event the piping becomes occluded. 

3.11.3 Measures for preventing leakage of collected flocs 

Sufficient care is taken for the painting and structure of the equipment and operation control at 

the time of any error to prevent floc leakage. 

3.11.4 Preventive measures for electric accidents 

The causes of electric accidents are overcurrent, electrification and electrical leak, so safety 

devices are provided for the local control panel and equipment. 

3.12 Maintenance 

The Hitachi Ballast Water Purification System is operated automatically as already described, 

and so no individual operation by ship crew is required and no dedicated operators are needed. 

This section describes the inspection work to be performed by the operator. The check results are 

to be record in a blotter and managed. 

3.12.1 Daily inspection 

Daily inspection requires only visual inspection of the following items before and after operation: 

- checking of error display; 

- storage quantity of chemicals; 
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- leakage from the equipment and piping; 

- appearance of the equipment and instruments; and 

- loose nuts and bolts. 

3.12.2 Periodic inspection/maintenance 

The outline is described below: 

- checking the operation of the devices (operation, vibration, abnormal sound, 

deformation, damage and oil leakage): monthly; 

- checking the storage status of chemicals (check the powder supply opening and 

liquid storage tank interior): monthly; 

- inspection and refilling of lubricant: monthly; 

- cleaning of the strainer: monthly; 

- replacement of the lubricant: yearly; 

- inspection/replacement of consumables: yearly; 

- cleaning of the chemical storage tank: yearly; 

- inspection and cleaning of the local control panel (looseness, contact status, 

damage on the insulated section, deformation and discoloration): yearly; 

- checking of insulation resistance for the cable and transformer: at docking; 

- checking of sequence: at docking; 

- checking of the painting and lining: at docking; and 

- disassembly for maintenance: every 5 years. 

3.12.3 Safety measures for humans and hull 

Safety precautions are required for inspection, recovery and maintenance work because 

chemicals, collected flocs or lubricant may leak and humans could be exposed to it. Basic safety 

precautions and actions in case of leakage or exposure are described below. 

(1) Safety precautions 

When supplying/inspecting chemicals and performing recovery work for leakage, operators 

should wear protective gear and take measures to prevent the leaked chemical from spreading 

and reduce the associated risks, because the chemicals could cause injury to operators and 

damage to the ship. 
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(2) Emergency treatment for exposure and measures in case of leakage 

If any chemicals or collected flocs leak, and a person are exposed to it, MSDS counter measures 

should be taken. As eye exposure poses the highest risk, a portable eye washer should be 

equipped nearby the working area. 

3.13 Supply and storage of chemicals 

3.13.1 Chemicals used in the system 

The following chemicals are used in this system. 

(1) Triiron tetraoxide 

 Name of substance (IUPAC): triiron tetraoxide 

Synonyms: Ferriferous oxide (Fe3O4), Ferrosoferric oxide, Iron ferrite, Iron oxide, Iron 

oxide black, Magnetic iron oxide, Magnetite (EU, 2000a) 

Molecular formula or structural formula: Fe3O4

Main use: Copier toner, Pigment, Coating material, Cosmetics 

(2) PAC 

Name of substance (IUPAC): Basic aluminium chloride 

Synonyms: Aluminium chlorhydrate, Aluminium chloride hydroxide, 

 Aluminium chloride hydroxide oxide, basic, 

 Aluminium chloride oxide, polyaluminium chloride, (EU, 2000b) 

Molecular formula or structural formula: [Al2(OH)nCl6-n]m (1≤n≤5, m≤10) 

Main use: Coagulant chemical for water processing (drinking water, sewage water, 

industrial waste water) 

(3) PASA 

Name of substance (IUPAC): Acrylamide sodium acrylate copolymer 

Synonyms: 2-Propenoic acid, sodium salt, polymer with 2-propenamide, 

2-Propenamide, polymer with sodium 2-propenoate, 

Acrylamide Sodium Acrylate Copolymer 

Molecular formula or structural formula 

CH2 CH n CH2 CH m

CONH2 COONa

Main use: Flocculant chemical for water processing (drinking water, sewage water, 

industrial waste water), Gel for electrophoresis 

3.13.2 Method of supplying chemicals 

The stable supply of chemicals is very important for this system, and so the supply bases and 

system should be established. 
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3.13.3 Storage of chemicals 

Chemicals are stored in the environment settings specified in section 3.4.1. The chemicals used 

in this system do not have a risk of ignitability or self-reaction, and the preventive measures for 

leakage described in section 3.11.1 assure the safety of humans and the hull structure. Material 

Safety Data Sheets (MSDS) for each chemical must be indicated in the same or adjacent area 

on board the ship, in which the chemical is stored. 

4 Assessment of treated water 

4.1 Water sampling 

Table 4-1 shows the rated treatment dose conditions for the chemicals, which are used for all 

analyses described in this section. 

Table 4-1 − Amount of additive chemicals (rated concentration) 

(Unit: mg/L) 

Additive chemical Addition concentration 

(mg/L) 

Triiron tetraoxide 30 

PAC 5 (as Al) 

PASA 1 

Tokyo 

Bay

Intake 

pump

Treatment 

equipment

Simulated 

Ballast Water Tank

Tokyo 

Bay

Untreated water 

is sampled. 

Treated water is sampled

at the outlet of the rotary 

filter separator, which is the 

final stage of the system.

Feed 

Tank

Treated water is s sampled

after 5 days’ storage.

Figure 4-1 – Schematic diagram of water sampling positions 

Samples of untreated water and treated water were taken from the appropriate sampling positions 

indicated in Figure 4-1. 

4.1.1 Measurement of pH and SS concentration 

Table 4-2 shows the average pH values of treated water and untreated water. These analyses were 

carried out with both the prototype in 2007 and the land-based set-up in 2008. The pH of treated 

water is lower than that of untreated water, but differs only slightly. The pH reduction is limited 

in the ambient water environment due to the mechanism of equilibrium, as described in the Basic 

Approval Application. Therefore no pH-reducing effect is expected in the aqueous environment, 

considering that the treated water is discharged immediately after treatment. The treated water 

has no corrosivity to ballast water tanks or other equipment in the ship. 
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Table 4-2 – Average pH value of treated water 

Treatment system Sample pH 

Untreated water 8.5 Land-based set-up Treated water 7.1 

Untreated water 8.3 Prototype Treated water 7.0 

(n=10) 

Table 4-3 shows the average SS concentration in treated water and untreated water. The results 

show that the SS concentration in the treated water of the loaded test was lower than 1 mg/L, as it 

also was in the control test. 

Table 4-3 – SS concentration of treated water 

(Unit: mg/L) 

SS concentration Treatment 

system Test Before 

treatment 

After 

Treatment LOD 

Control 1) Land-Based 5 or < 5 < 1 

Test Equipment Loaded test 2) 50 ~ 60 < 1 1 

Control 1) Prototype 5 or < 5 < 1 

Equipment Loaded test 2) 50 ~ 60 < 1 1 

1) Actual seawater taken from Tokyo BayLOD: Limit of Detection; (n=10) 

2) Kaolin was added to the actual seawater before the treatment 

The above test results show that this system is appropriate for use in large-scale treatment in 

terms of its pH and SS removing performance. 

4.1.2 Compliance with regulation D-2 of the BWM Convention 

This section evaluates the qualities of water treated by the land-based treatment test equipment 

and shipboard test equipment with respect to regulation D-2. All of the results satisfy 

regulation D-2, verifying that this technology is reliable under both land-based and shipboard 

conditions. 

Table 4-4 shows a typical example of analysis of water treated by the land-based treatment test 

equipment and Table 4-5 shows another typical result produced by the shipboard test equipment 

in accordance with Guidelines (G8). 
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Table 4-4 − Typical example of analysis of treated water 

(Land-based test set-up) 

Item Unit Untreated 

watera)

Treated 

water b) Control c) Criteria

Viable organisms 

50 μm or larger Units/m3

 5,700,000 0 7,200,000 <10 

Viable organisms 

10 – 50 μm Units/ml 15,000 <1 1,100 <10 

E. coli cfu/100mL 18,000 <1 1,600 <250 

Toxicogenic Vibrio 

cholerae (O1 and O139) cfu/100mL <1 <1 <1 <1 

Intestinal enterococci cfu/100mL <1 <1 <1 <100 

Test conducted in September 2008 

(a) Analysed sample taken immediately before the treatment equipment 

(b) Analysed at discharge after holding period 

(c) Analysed at discharge after holding period 

Table 4-5 – Typical example of analysis of treated water 

(Shipboard test set-up) 

Item Unit Untreated 

water a)

Treated 

water b) Control c) Criteria

Viable organisms 

50 μm or larger Units/m3

 31,603 0 8,392 <10 

Viable organisms 

10 – 50 μm Units/ml 155 <1 15 <10 

E. coli cfu/100mL <1 <1 <1 <250 

Toxicogenic Vibrio 

cholerae (O1 and O139) cfu/100mL <1 <1 <1 <1 

Intestinal enterococci cfu/100mL <1 <1 <1 <100 

Test conducted in May 2008 

(a) Analysed sample taken immediately before the treatment equipment 

(b) Analysed at discharge after holding period 

(c) Analysed at discharge after holding period 

4.1.3 Quantities of substances derived from additive chemicals in treated water 

(1) Samples 

The quantities of substances in the sample water treated by the land-based test set-up on 

reclaimed land in Tokyo Bay (treatment rated capacity of 200 m3

/hr) have been determined by 

analysis. 

(2) Dosage concentration 

The quantities of chemicals used in this test matched the rated operating conditions 

(see Table 4-1). 
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4.1.4 Result of analysis 

4.1.4.1 Active Substances 

(1) Aluminium 

Table 4-6 shows the results. 

Table 4-6 – Aluminium concentration of treated water 

(Unit: mg/L) 

Sample Value Limit of Detection 

Untreated Water 0.048 

Treated Water 0.022 

0.001 

(2) Iron 

Table 4-7 indicates that iron was not detected in treated water. 

Table 4-7 – Iron concentration of treated water 

(Unit: mg/L) 

Sample Value Limit of Detection 

Untreated Water 0.05 

Treated Water Not detected 

0.01 

(3) Acrylamide monomers 

Table 4-8 indicates that no acrylamide monomers were detected in either treated or untreated 

water. 

Table 4-8 – Acrylamide monomers concentration of treated water 

(Unit: mg/L) 

Sample Value Limit of Detection 

Untreated Water Not detected 

Treated Water Not detected 

0.0001 

(4) PASA 

PASA concentration was measured by PGC-MS. Table 4-9 shows that PASA was not detected 

in either untreated water or treated water. 
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Table 4-9 – PASA concentration of treated water 

(Unit: mg/L) 

Sample Untreated Water Treated Water Limit of 

Detection 

1 Not detected Not detected 0.1 

2 Not detected Not detected 0.1 

4.1.4.2 Others 

(1) Harmful heavy metals 

Table 4-10 shows the result of harmful heavy metals analysis (CERI, 2008 g). No harmful heavy 

metals were detected in treated water. 

Table 4-1 – Harmful Heavy Metals concentration of treated water 

(Unit: mg/L) 

Metal Value Limit of 

Detection 

Cadmium (Cd) Not detected 0.002 

Lead (Pb) Not detected 0.005 

Mercury (Hg) Not detected 0.0001 

Chromium [VI] (Cr[VI]) Not detected 0.02 

Arsenic (As) Not detected 0.001 

Selenium (Se) Not detected 0.001 

(2) VOCs 

Table 4-11 shows the VOC quantities in treated water, measured by purge-and-trap gas 

chromatograph-mass spectrometry as quantitative and qualitative analysis. No VOCs were 

detected in treated water (CERI, 2008h). 
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Table 4-11 – VOCs of treated water 

(Unit: mg/L) 

VOC Value 

1,1-dichloroethylene Not detected 

Dichloromethane Not detected 

Trans-1,2- dichloroethylene Not detected 

Cis-1,2- dichloroethylene Not detected 

Chloroform Not detected 

1,1,1-trichloroethane Not detected 

Carbon tetrachloride Not detected 

Benzene Not detected 

1,2-dichloroethane Not detected 

Trichloroethylene Not detected 

1,2-dichloropropane Not detected 

Bromodichloromethane Not detected 

Cis-1,3-dichloropropene Not detected 

Toluene Not detected 

Trans-1,3-dichloropropene Not detected 

1,1,2-trichloroethane Not detected 

Tetrachloroethylene Not detected 

Dibromochloromethane Not detected 

m,p-xylene Not detected 

O-xylene Not detected 

Bromoform Not detected 

P-dichlorobenzene Not detected 

Limit of Detection: 0.0001 mg/L as converted into toluene 

4.2 Quality of collected floc 

The potential concentration of naturally present substances of intake water and chemicals in the 

collected flocs needs to be examined and assessed in detail. Therefore identification of heavy 

metal, VOC, and acrylamide monomers was performed. The analysis identification used the 

collected flocs produced in processing seawater at the land-based test set-up and/or prototype test 

set-up on reclaimed land in Tokyo Bay. 

4.2.1 Analysis and results 

(1) Harmful heavy metal 

Hence the analysis employed elution analysis, which is conventionally used for solids such 

as mud, to identify heavy metals in the collected flocs (HPS, 2008b). As stated in Table 4-12, the 

analysis results show that the heavy metals surveyed were not detected. 
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Table 4-12 – Elution analysis of heavy metal in floc 

(Unit: mg/L) 

Metal Value Limit of 

Detection 

Mercury (Hg) Not detected 0.0005 

Cadmium (Cd) Not detected 0.001 

Lead (Pb) Not detected 0.001 

Chromium [VI] (CrVI]) Not detected 0.005 

Selenium (Se) Not detected 0.001 

(2) VOC 

Purge and trap gas chromatography mass spectrometry was used to quantify VOC in flocs. The 

results show that no VOC was detected as shown in Table 4-13. 

Table 4-2 – VOCs in floc 

(Unit: mg/kg) 

Item Value 

Benzene Not detected 

Tetrachloroethylene Not detected 

Trichloroethylene Not detected 

1,2-dichloroethane Not detected 

Dichloromethane Not detected 

1,1,1-trichloroethane Not detected 

Carbon tetrachloride Not detected 

1,1-dichloroethylene Not detected 

Cis-1,2- dichloroethylene Not detected 

1,1,2-trichloroethane Not detected 

1,3-dichloropropene Not detected 

Limit of Detection: 0.0001mg/L as conversion into Toluene 

(3) Acrylamide monomers 

Table 4-14 shows analysis results from chromatography mass spectrometry to quantify 

acrylamide in flocs. The results show that no acrylamide monomer was detected as shown in 

Table 4-14. 

Table 4-3 – Acrylamide monomers in floc 

(Unit: mg/kg) 

Substance Value Limit of 

Detection 

Acrylamide monomers Not detected 0.02 
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4.2.2 Conclusions of analysis 

As stated above, flocs collected from processing seawater in rated concentration of chemical 

concentrations as shown in Table 4-1 were found to contain no harmful heavy metal, acrylamide 

monomers, or VOC (the detected value is lower than the detection limit). 

5 Ecotoxicity test of treated ballast water 

In this section, the results of ecotoxicity studies with treated ballast water as a test substance are 

presented in accordance with the Procedure for approval of ballast water management systems 

that make use of Active Substances (G9). 

5.1 Acute toxicity test 

In accordance with the Methodology for information gathering and the conduct work of the 

GESAMP-BWWG (IMO circular BWM.2/Circ.13), the acute toxicity tests for high and low 

salinity water were performed using water treated by this system (IDEA, 2008f, 2008g). 

5.1.1 Test set-up 

The land-based treatment test with high and low salinity water was performed using a land-based 

test set-up of the Hitachi Ballast Water Purification System in accordance with the 

IMO Guidelines for approval of Ballast Water Management Systems (G8). The treated-water 

discharge (hereinafter “TWD”) samples (i.e. simulated ballast water discharge) were produced 

and subjected to toxicity tests. 

5.1.2 Toxicity test results for high salinity water 

Acute toxicity tests of 1-day-hold and 5-day-hold TWD samples (high salinity range; >32 psu) on 

algae, invertebrates, and fish were conducted by a GLP compliant laboratory. From the results 

shown in Table 5-1, it is concluded that 100% treated ballast water, which is a non-diluted 

sample of treated water, by this system has no toxicity impact on these aquatic species 

(IDEA, 2008f). 

 

Table 5-1 – NOEC of treated ballast water for high salinity water 

Test sample Classification Species End point NOEC 

Algae Skeletonema 

costatum

Growth 

inhibition 

72-h NOEC 

100% treated 

ballast water*

Invertebrate Hyale 

barbicornis

Mortality 

96-h NOEC 

100% treated 

ballast water*

1-day-hold treated 

water discharge 

sample 

Fish Oryzias 

javanicus

Mortality 

96-h NOEC 

100% treated 

ballast water*

Algae Skeletonema 

costatum

Growth 

inhibition 

72-h NOEC 

100% treated 

ballast water*

Invertebrate Hyale 

barbicornis

Mortality 

96-h NOEC 

100% treated 

ballast water*

5-day-hold treated 

water discharge 

sample 

Fish Oryzias 

javanicus

Mortality 

96-h NOEC 

100%treated 

ballast water*

*

 No effects were observed in 100% treated ballast water which is a non-diluted sample of treated water. 
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5.1.3 Toxicity test results for low salinity water 

Acute toxicity tests of 1-day-hold and 5-day-hold TWD samples (low salinity range; <22 psu) on 

algae, invertebrates, and fish were conducted by a GLP compliant laboratory. From the results 

shown in Table 5-2, it is concluded that 100% treated ballast water, which is a non-diluted 

sample of treated water, by this system has no toxicity impact on these aquatic species 

(IDEA, 2008g). 

Table 5-2 − NOEC of treated ballast water for low salinity water 

Test sample Classification Species End point NOEC 

Algae Skeletonema 

costatum

Growth 

inhibition 

72-h NOEC 

100% treated 

ballast water*

Invertebrate Hyale 

barbicornis

Mortality 

96-h NOEC 

100% treated 

ballast water*

1-day-hold treated 

water discharge 

sample 

Fish Oryzias javanicus Mortality 

96-h NOEC 

100% treated 

ballast water*

Algae Skeletonema 

costatum

Growth 

inhibition 

72-h NOEC 

100% treated 

ballast water*

Invertebrate Hyale 

barbicornis

Mortality 

96-h NOEC 

100% treated 

ballast water*

5-day-hold treated 

water discharge 

sample 

Fish Oryzias javanicus Mortality 

96-h NOEC 

100% treated 

ballast water*

*

 No effects were observed in 100% treated ballast water which is a non-diluted sample of treated water. 

As stated above, no effects were observed in all species in 100% treated ballast water, which is 

a non-diluted sample of treated water, for high and low salinity water. 

5.2 Chronic toxicity test 

5.2.1 Test set-up 

Seawater was treated with the prototype test set-up installed on reclaimed land in Tokyo Bay 

which simulates the ballast water purification system (treatment rated capacity of 50 m3

/hr) and 

the samples of treated water were analysed. 

5.2.2 Materials and methods 

In order to evaluate the hazards of Active Substances to aquatic organisms, the substances were 

injected into seawater collected from Tokyo Bay to produce final concentrations two times 

higher than those of the rated processing conditions for this system (Table 5-3) and the treated 

water samples collected by this system were analysed. 
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Table 5-3 – Final concentrations of chemicals after injection for chromic toxicity test 

(Unit: mg/L) 

Active Substance Concentration in untreated 

seawater 

Triiron tetraoxide 60 

PAC 10 (as Al) 

PASA 2 

Approximately 20 L of the treated water was sampled from the effluent in the outfall of the filter 

separator when the processing had been carried out for 16 to 32 minutes (see section 4.1). The 

sample of treated water was put in a 20-L polyethylene bottle and transported to the test facility 

in cool, shaded conditions. All the samples of treated water were carried into the test facility the 

next day and were used in the toxicity tests. 

5.2.3 Test results 

The chronic toxicity tests using the water treated by this system on algae, invertebrates, and fish 

were conducted by a GLP compliant laboratory. From the results shown in Table 5-4, it is 

concluded that 100% treated ballast water, which is a non-diluted sample of treated water, by this 

system has no toxicity impact on these aquatic species (IDEA, 2007a, b, c). 

Table 5-1 – NOEC on chronic toxicity of treated ballast water for high salinity water 

Test 

sample Classification Species End point NOEC 

Algae Skeletonema 

costatum

Growth inhibition 

72-h NOEC 

100% treated 

ballast water*

Invertebrate Hyale 

barbicornis

Mortality 

21-days NOEC 

100% treated 

ballast water*

Treated 

ballast 

water 

Fish Oryzias 

javanicus

Post-hatch mortality 

40-days NOEC 

100% treated 

ballast water*

*

No effects were observed in 100% treated ballast water which is a non-diluted sample of treated water. 

As stated above, no chronic toxicity effects were observed in all species in 100% treated ballast 

water, which is a non-diluted sample of treated water. 

5.3 Study on effects of treated water under higher concentration of Active Substances 

5.3.1 Ecotoxicity tests of water with flocs 

Concerning water containing flocs generated in the rated additive concentration of chemicals by 

this system, ecotoxicity tests were carried out to evaluate the effect of water treated with a high 

concentration of Active Substances on organisms. 

The test results indicate that flocs in treated water (100% floc water) generated by the Hitachi 

Ballast Water Purification System at the rated condition of chemicals had no physical effect on 

aquatic organisms such as zooplankton and fish. 
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5.3.2 Conclusions of study on water treated at high concentration conditions of Active 

Substances 

As stated in the previous sections, ecotoxicity tests of water containing flocs generated by this 

system to evaluate the upper limit of additive chemical concentrations, and the adverse effect 

(including physical and ecotoxicity) of water treated with a high concentration of Active 

Substances on organisms were carried out. The results indicate that the water treated with the 

rated amounts of chemicals, the water treated with double the amounts of chemicals, and flocs 

themselves have no toxic effect on organisms. The safety of treated water provided by this 

system is thus verified. 

6 Risk characterization and risk assessment 

6.1 Summary of critical information of substances 

6.1.1 Physical chemical properties of Active Substances and treated ballast water 

(G9:4.2.1.4) 

The relevant physical chemical properties in Table 6-1 show that all the substances listed are well 

known and that the chemicals employed are relatively harmless except for undiluted PAC 

solution, which is acidic and slightly corrosive, as stated in the application for Basic Approval. 

In water, the chemical characteristics of the listed materials other than PAC are relatively simple. 

However, dissolved aluminium compounds, including PAC, show complicated chemical 

characteristics. 

Table 6-1 – Physical chemical properties 

Property Triiron 

tetraoxide PAC PASA Acrylamide monomers 

Treated 

ballast 

water 

CAS No. 1317-61-9 1327-41-9 25085-02-3 79-06-1 None 

Melting point 

(°C) 

1,538 1) About -12 2) Not Applicable 84.5 1) NR9)

Boiling point (°C) Not 

Applicable 

About 103 2) Not Applicable 125 at 3kPa 1) NR 

Flammability 

(Flash point for 

liquids; °C) 

Not 

Applicable 

Non-combustible5) None#1, 4) 138 (closed 

method) 3)

NR 

Density (20°C; 

kg/m3) 

5,200 

(5.2g/cm3) 1)

1,340 

(1.34g/cm3) 2)

Bulk specific 

gravity; 

0.55-0.65 4)

1,130(1.13g/cm3) 

3)

NR 

Vapour pressure 

(20°C; Pa) 

Not 

Applicable 

Non-evaporable 

5)

Nonevaporable #21 3) NR 

Vapour density 

(air = 1) 

Not 

Applicable 

Not Applicable Not Applicable 2.46 (calculated 

value) 

NR 

Water solubility 

g/L 

Insoluble 6) Soluble1) Mixing with 

water forms 

highly viscous 

gel-like 

material 4)

2,040 (25°C) NR 
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Property Triiron 

tetraoxide PAC PASA Acrylamide monomers 

Treated 

ballast 

water 

Oxidationreduction 

potential 

Not 

Applicable 

None 5) None 4) None 7) None 

Corrosivity to 

materiaequipment 

None Corrosive to 

metals 

None None None 

Autoignition 

temperature (°C) 

Not 

Applicable 

Non-combustible5) None 4) 424 3) NR 

Explosive 

properties 

Not 

Applicable 

None None None 7) NR 

Oxidizing 

properties 

Not 

Applicable 

None 5) None 4) None 7) NR 

Surface tension None Equal to water 

because of 

aqueous solution 

None None NR 

Viscosity 

(mPa.s) 

None 28 mPa·s (25°C)2) Mixing with 

water forms 

highly viscous 

gel-like 

material 4)

2.71 mPa·s 

(25°C) (50% 

aqueous 

solution) 8)

1.55cP 

(16°C) 

Thermal stability Transformed 

into iron 

oxide 

(Fe2O3) by 

heating in 

air1)

Non-flammable Combustible by 

heating at high 

temperature 

Violently 

polymerizes 

when heated to 

over 85°C or 

when exposed to 

of light or 

oxidizing agents. 

When heated to 

decomposition, 

fumes and 

nitrogen oxide 

are generated. 3), 

8)

NR 

Reactivity to 

storage tank 

material 

None None None None NR 

pH in solution NR NR 4.3 (15%) 1) NR NR 7 - 7.3 

Salinity N.D. 

Conductivity 4.5 S/m 

TOC 1.3 

mg/L 

DOC N.D. 
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Property Triiron 

tetraoxide PAC PASA Acrylamide monomers 

Treated 

ballast 

water 

Other physicochemical 

properties 

None None None Because 

acrylamide 

readily 

polymerizes, 

common 

products contain 

polymerization 

inhibitors1)

None 

Dissociation 

constant (pKa) 

Not 

Applicable 

No dissociable 

group 

No dissociable 

group 

No dissociable 

group 

NR 

1) Merck, 2006, 2) EU, 2000b, 3) IPCS, 2000, 4) Dia-Nitrix, 2004, 5) Asada Chemical Industry, 2003, 

6) Dean,1999, 7) EU, 2002, 8) HSDB, 2007, 9) NR: not required for G9 

#1 Non-combustible under conditions of normal use (normal pressure, 0-50°C). 

 #2 Non-evaporable under normal pressure and normal temperature because of high molecular weight 

polymers (several million or more).

6.2 Risk assessment with regard to ship safety 

Specific countermeasures that can be employed in this system to deal with envisaged problems 

during the ballast water purification have been discussed. 

6.3 Risk to human health 

6.3.1 Data on NOAELs to be used in the assessment of risk to human health 

Data from key studies which can be utilized in the assessment of risk to human health are shown 

in Table 6-2. 
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Table 6-2 – Key studies utilized in the assessment of risk to human health 

Substance Test Species Route Duration Result References 

Iron oxide 

(Reference) Occupation Human Inhalation - TLV-TWA: 5 mg/m3 1) ACGIH, 2005 

Triiron 

tetraoxide 

Repeated 

toxicity - 

Oral 

(drinking 

water) 

- - - 

PAC Repeated 

toxicity Rat Inhalation 6 months LOAEL: 0.25 mg/m3 Steinhagen et al., 1978 

PAC Repeated 

toxicity - 

Oral 

(drinking 

water) 

- - - 

Aluminium 

(Reference) 

Repeated 

toxicity Human 

Oral 

(drinking 

water) 

0.1 mg/L or 

less2)

0.2 mg/L or 

less 

WHO, 

2003b 

PASA Repeated 

toxicity - Inhalation - - - 

PASA Repeated 

toxicity - 

Oral 

(drinking 

water) 

- - - 

PASA Repeated 

toxicity 

Rat, 

dog 

Oral 

(feeding) 2 years NOAEL: >5% 

Cosmetic 

Ingredient 

Review, 

2005 

Acrylamide 

monomers Occupation Human Inhalation - TLV-TWA: 0.03 mg/m3 3) ACGIH, 2005 

Acrylamide 

monomers 

Repeated 

toxicity Rat 

Oral 

(drinking 

water) 

90 days 

NOAEL: 

0.2 

mg/kg/day 

EU, 2002; 

NTPCERHR, 

2005 

1) Measured as respirable fraction of the aerosol. 

2) Owing to the uncertainty surrounding the human data and the limitations of the animal data as a model for 

humans, a health-based guideline value for aluminium cannot be derived at this time (WHO, 2003b). 

Therefore, the practicable level is derived based on optimization of the coagulation process in 

drinking-water plants using aluminium-based coagulants, to minimize aluminium levels in finished water. 

Concentrations of aluminium of 0.1 mg/L or less are achievable in large water treatment facilities. For 

small facilities (e.g., those serving fewer than 10,000 people), 0.2 mg/L or less is a practicable level for 

aluminium in finished water (WHO, 2003b). 

3) Measured as inhalable fraction and vapour. 

6.3.2 Assessment of exposure and risk to humans 

The target populations of exposure and risk assessment are ships’ crew who may be at risk of 

occupational exposure [1] in Figure 6-1 as well as people in the general population who may be 

subjected to indirect exposure by way of sea bathing or through the environment [2] in 

Figure 6-1. 
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[1] Ship Crew

Aquatic Organisms

[2] General 

Population

Air

Ballast Water Discharge

Aquatic 

Environment

Food, 

Drinking Water

[1] Ship Crew

Aquatic Organisms

[2] General 

Population

Air

Ballast Water Discharge

Aquatic 

Environment

Food, 

Drinking Water

Figure 6-1 – Schematic diagram of target populations of exposure 

and risk assessment for this system 

In the Technical Guidance Document on Risk Assessment (ECB, 2003) and the Methodology 

for information gathering and the conduct work of the GESAMP-BWWG (IMO circular 

BWM.2/Circ.13, Appendix 2, “Human Exposure Assessment”) the following procedures for the 

assessment of exposure and risk to human health have been recommended: 

.1 identification of exposure routes and development of exposure scenarios for 

respective exposure routes; and 

.2 estimation of the amounts of exposure (intake) and risk assessment. 

Specifically, risk assessment is to be conducted by comparing the margin of safety (MOS), which 

can be calculated by dividing the NOAEL (no observed adverse effect level) in humans or 

experimental animals by the estimated amount of exposure, with MOSref (100) in compliance 

with the “Human Exposure Assessment” mentioned above. 

MOS = NOAEL/estimated exposure amount 

Among the data on NOAELs to be used in the assessment of risk to human health, as shown in 

Table 6-2, those obtained in toxicity studies in mammals which have been judged to be 

applicable to the present risk assessment are shown in Table 6-4. 

Table 6-3 – Results of assays of chemicals in treated ballast water 

(Unit: mg/L) 

Substance Concentration in 

discharged ballast water Limit of Detection 

Aluminium 0.022 0.002 

PASA n.d. 0.1 

Acrylamide monomers n.d. 0.0001 

Iron n.d. 0.01 
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Table 6-4 – Data on toxicity studies in mammals utilized in risk assessment 

Substance Test Route Species Duration Result References 

PASA Repeated 

toxicity 

Oral 

(feeding) Dog 2 years 

NOAEL: 

>1,250 

mg/kg/day1)

Cosmetic 

Ingredient 

Review, 2005 

Acrylamide 

monomers 

Repeated 

toxicity 

Oral 

(drinking 

water) 

Rat 90 days 

NOAEL: 

0.2 

mg/kg/day 

EU, 2002; 

NTPCERHR, 

2005 

Aluminium (Guideline for drinking water treatment 

facility) 

0.2 mg/L 

(small facility) 

0.1 mg/L 

(large facility)

WHO, 2003b 

1) convert mixing ratio 5% of dose level into dose amount per kilogram of body weight(food intake data 

referred to Lehman, A.J. (1954) ) 

6.3.3 Assessment of exposure to ships’ crew 

6.3.3.1 Identification of exposure routes and exposure scenarios 

In this section, recalling the recommendations of the GESAMP-BWWG (see section 2), work 

operations to be performed in this system that may serve as routes of exposure to humans will be 

identified, and exposure scenarios for the respective exposure routes are examined. 

6.3.3.2 Estimation of the amount of exposure and risk assessment 

Exposure scenarios for the respective operation processes were examined. It was confirmed that 

measures adopted in this system make it possible to minimize the risk of human exposure to 

chemicals to be used in this system and flocs through all of the exposure routes assessed 

including percutaneous, oral and inhalation. 

Risk to human health (i.e. workers in this case) of exposure to floc is judged to be very low based 

on the facts that measures, such as washing in nearby washing facilities, can be taken in 

preparation that accidental exposure to the eyes or skin occurs. 

6.3.4 Exposure of general population through the environment 

In this section, exposure routes and exposure scenarios will be examined for possible exposure of 

general population through the environment that may occur after the discharge of active 

chemicals from this system. 

6.3.4.1 Identification of exposure routes and exposure scenarios 

Possible scenarios of exposure to the general population through the environment are limited to 

the following: 

Scenario 1: Oral exposure (through water drinking) of sea bathers and workers in the 

surrounding water areas; and 

Scenario 2: Oral exposure to the general population through the food chain (by way of marine 

foods). 
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6.3.4.2 Estimation of the amounts of exposure and risk assessment 

In this section, estimation of the amounts of exposure and risk assessment will be conducted for 

the respective exposure scenarios. 

(1) PAC 

As shown in paragraph 4.1.4.1 (1), the concentration of aluminium in treated ballast water was 

found to be 0.022 mg/L. This value is substantially smaller than the feasible target concentration 

of aluminium in tap water specified by WHO, that is, 0.1 mg/L or 0.2 mg/L (for large and small 

drinking water treatment plants, respectively). Therefore, there is no risk of exposure by the oral 

route (water drinking) to aluminium contained in treated ballast water. 

In the assessment of risk to the general population of oral exposure through the food chain by 

way of marine products, bioconcentration in marine organisms does not need to be considered for 

PAC, and there may be no risk to the general population of oral exposure to PAC through the 

food chain. 

(2) PASA 

While the concentration of PASA in treated ballast water was found to be less than 0.1 mg/L, as 

shown in Table 4-9, its concentration is expected to be further diluted in discharged water area. 

MOS has been estimated in accordance with a worst-case scenario, in which no dilution in water 

is assumed to occur, under the assumption that the water concentration of PASA derived from 

treated ballast water is 0.1 mg/L. 

MOS = 1,250 mg/kg/day/(0.0003 mg/kg/day) 

 = 4.2 x 106

Since this MOS value is substantially higher than the MOSref (100), it can be judged that 

exposure through water drinking to PASA derived from discharged treated ballast water will not 

affect the health of sea bathers or workers in surrounding water areas. 

In the assessment of risk to the general population of oral exposure through the food chain by 

way of marine products, bioconcentration in marine organisms does not need to be considered for 

PASA, and it would appear that there is no risk to the health of humans (the general population) 

by the oral route through the food chain. 

(3) Acrylamide monomers 

While the concentration of acrylamide monomers in treated ballast water was found to be less 

than 0.0001 mg/L, as shown in Table 4-8, its concentration is expected to be further diluted in 

discharged water area. MOS has been estimated in accordance with a worst-case scenario, in 

which no dilution in water is assumed to occur. Under this assumption, the concentration of 

acrylamide monomers derived from treated ballast water is 0.0001 mg/L. 

MOS = 0.2 mg/kg/day/(3.3 x 10-6 mg/kg/day) 

 = 6.1 x 104
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Since this MOS value is substantially higher than the MOSref (100), it can be judged that 

exposure through water drinking to acrylamide monomers derived from discharged treated 

ballast water will not affect the health of sea bathers or workers in surrounding water areas. 

In the assessment of risk to the general population of oral exposure through the food chain by 

way of marine products, bioconcentration in marine organisms does not need to be considered for 

PASA, and it would appear that there is no risk to the health of humans (the general population) 

by the oral route through the food chain. 

(4) Triiron tetraoxide 

While the concentration of iron in treated ballast water was found to be less than 0.01 mg/L, as 

shown in Table 4-7, its concentration is expected to be further diluted in discharged water area. 

On the other hand, the concentration of iron in water has been reported to be 10 μg/L (0.01 mg/L) 

in seawater and 1 mg/L in river water (OECD, 2007). These findings indicate that iron 

concentration in treated ballast water is similar to or less than that in the water areas into which 

treated ballast water is to be discharged, and that iron in discharged treated ballast water will not 

alter the iron concentration in the environment. Therefore, it can be judged that the amount of 

iron, which is derived from discharged treated ballast water, ingested by sea bathers or workers 

in surrounding water areas through water drinking is very small (negligible). 

In the assessment of risk to the general population of oral exposure through the food chain by 

way of marine products, as has been clarified in the Basic Approval application dossier, the 

accumulation of iron in the marine organisms does not need to be considered. Taken together, 

it would appear that there is no risk to the health of humans (the general population) by the oral 

route through the food chain. 

6.3.5 Conclusion of risk assessment for exposure to ships’ crew and the general 

population 

In this system, the risk to ships’ crew is judged to be appropriately managed based on the facts 

that chemicals themselves to be used, that is, triiron tetraoxide, PAC and PASA, have low 

toxicity, and that the percentage of the content of acrylamide monomers, which is a hazardous 

substance present in PASA as an impurity, is maintained at a low level, as well as that system 

components are adopted that are expected to minimize the exposure risk of ships’ crew to 

chemicals and ballast water before/after treatment. 

In addition, it is reasonably considered that the system has no risk to the health of the general 

population in light of the facts that exposure routes are very limited and that the amounts of 

possible exposure are very small. 

In conclusion, it is reasonably considered that the system has no risk to human health including 

ships’ crew and the general population. 

6.4 Risk assessment on aquatic organisms 

The chemical characteristics in water of the substances used in this system other than PAC are 

relatively simple. However, dissolved aluminium compounds, including PAC, show complicated 

chemical characteristics. Therefore, aluminium is separately discussed from the other chemical 

additives (section 6.4.2). Triiron tetraoxide, PASA, and acrylamide monomers are discussed in 

section 6.4.3. 
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6.4.1 PBT assessment (G9: 6.4.1) 

As corroborated at the Basic Approval, none of the triiron tetraoxide, PAC, PASA, and 

acrylamide monomers are classified as PBT substances. 

6.4.2 Risks of aluminium to the aquatic environment 

Aluminium is the most abundant metallic element on earth and constitutes 8.13% of the earth’s 

crust. Natural sources of aluminium released to aquatic systems include weathering of rocks, 

glacial deposits and soils and their derivative minerals and atmospheric deposition of dust 

particles (WHO, 1997; EC and HC, 2000). It is not recognized as a toxic substance in natural 

marine environment due to the high concentration of it found in clay particles in marine waters 

and its relatively constant pH of approximately 8.2. Clay particles tend to bind rapidly with 

aluminium and form large colloids, thus removing aluminium from the water column. Therefore, 

the concentrations of dissolved aluminium in seawater remain low in accordance with the 

equilibrium of aluminium speciations, in spite of the existence of a wide variety of natural 

aluminium sources (WHO, 1997; CCME, 2003; EC and HC, 2000). 

6.4.2.1 Previous risk assessment of aluminium in reports of international bodies and 

governmental bodies 

The following is a summary of representative evaluations of aluminium effects as previously 

reported by international bodies and governmental bodies. 

(1) WHO, Environmental Health Criteria, 194 Aluminium, 1997 

Hazards posed to human health by aluminium have been systematically identified in a number of 

previous studies. However, no evidence has yet been produced that supports the primary 

causative role of aluminium in Alzheimer’s disease that has been suggested. Nor is there any 

indication that aluminium is carcinogenic. Taking these facts together, it has been concluded that 

there is insufficient health-related evidence to justify revising the existing WHO Drinking-Water 

Guidelines with respect to aluminium. 

(2) WHO, Guideline for drinking water quality, 2006 

Owing to the limited amount of data relevant to the effects of aluminium on animals and the 

uncertainty surrounding available data on its effect on humans, no accurate health-based 

guideline values on it can be derived. However, practicable levels based on optimization of the 

coagulation process in drinking-water plants using aluminium-based coagulants have been 

derived as 0.1 mg/L or less in large water treatment facilities, and 0.2 mg/L or less in small 

facilities. 
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(3) EC and HC (2000), Canadian Environmental Protection Act 1999, Priority 

Substances List Assessment Report for Aluminium Chloride, Aluminium Nitrate, 

Aluminium Sulfate 

This report characterized the environmental risk of aluminium posed to pelagic organisms. 

Environmental exposure to aluminium in water is assumed to be greatest in areas in proximity to 

places where process wastewater (backwash water) is directly released to aquatic environments 

from drinking water treatment plants. Table 5 of EC and HC (2000) presents estimated total 

aluminium concentrations in backwash waters for 13 drinking water treatment plants, including 

those with the highest estimated levels of concentration. The total aluminium levels present in 

effluent from drinking water treatment plant wastewater were measured (Table 5 

of EC and HC, 2000; 0.76~115mg/L). In order to estimate the amount of bioavailable aluminium 

present in rivers, the report performed speciation with MINEQL + and WHAM models. 

These models calculated the concentration levels of dissolved inorganic monomeric forms of 

aluminium following the releases of wastewater from selected drinking water treatment plants, 

using the estimated aluminium level in effluents and assuming a 1:10 dilution. 

The possibility that modelled concentrations overestimate actual values is further supported by 

measured data. The report concluded that organisms are unlikely to be exposed to harmful levels 

of aluminium as a result of using aluminium to treat water. 

In a study done with collected flocs, it was concluded that all the collected flocs tested were 

non-toxic using a microbial test and acutely and subacutely non-toxic to rainbow trout. 

6.4.2.2 Risk assessment of aluminium on aquatic organisms 

(1) Assessment of aluminium ion concentration in the natural environment water 

As a prerequisite for assessing the influence of aluminium contained in treated ballast water, the 

literature of aluminium concentration in natural water areas was surveyed especially where 

intake/discharge of ballast water is conducted. 

Consideration of natural background concentration in risk assessment has been recommended in 

guidance for the risk assessment of various metals, and this recommendation has been carried out 

(ICMM, 2007a, b; EA 2008, etc.). 

(2) Analysis of aluminium concentrations in treated water and influent 

Concentrations of aluminium in treated water and influent are compared in this section. 

As shown in section 4.1.4.1, aluminium was detected in influent (seawater) collected in Tokyo 

Bay, and concentrations of total aluminium in treated water were constantly lower than that in the 

influent as shown in Table 6-5 

Table 6-5 – Results of qualitative analysis of aluminium 

 (Case where influent was seawater) 

 (Unit: mg/L) 

Seawater Treated water Detection limit 

0.048 0.022 0.001 
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In addition, tests were performed using influent (seawater) to which kaolin was added to increase 

the SS concentration and the concentrations of aluminium in the influent were higher than in 

actual seawater. The test results are shown in this section. Kaolin is a natural mineral containing 

aluminium so the concentrations of total aluminium in the influent were several times higher than 

in actual seawater. Table 6-6 shows that the total aluminium concentrations in the treated water 

were lower than in influent (seawater). 

Table 6-6 – Results of qualitative analysis of aluminium 

 (Case where kaolin was added to influent (seawater)) 

 (Unit: mg/L) 

Influent* Treated water Detection limit 

0.34 0.044 0.001 

As shown above, it is verified that this system removes aluminium in the influent. Consequently, 

the treated water has almost no effect on aluminium concentration in the water area discharged. 

(3) Risk assessment from a quantitative evaluation of aluminium risk according 

to EC and HC (2000) 

Tables 6-7 and 6-8 show the key study of the acute toxicity and chromic toxicity of aluminium 

selected from the hazard data on aluminium for aquatic organisms. Considering that the total 

aluminium concentration in the treated ballast water using this system was 1/10 to 1/10000 

smaller than that in the effluent described in the report (0.76 to 115 mg/L, EC and HC, 2000), it 

can be reasonably concluded that organisms are unlikely to be exposed to harmful levels of 

aluminium resulting from the use of aluminium for ballast water treatment. 

Table 6-1 − Key study of the acute toxicity of aluminium 

Substance Biological 

classification Organism species End point Toxicity (mg/L) 

Skeletonema costatum, 

SW

Growth 

inhibition 

72-h EC50

4.65 mg 

Al 

Algae 

Pseudokircheneriella 

subcapitata, FW

Growth 

inhibition 

96-h EC50

0.57 mg 

Al 

Invertebrates Nitocra spinipes, SW Mortality 

96-h LC50 10 mg Al 

Shellfish Physa sp., FW Mortality 

96-h LC50

30.6 mg 

Al 

Aluminium 

ions 

Amphibia Bufo americanus, FW Mortality 

96-h LC50

0.86 mg 

Al 

Abbreviations: SW: marine species, FW: fresh water species 
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Table 6-2 − Key study of chronic toxicity of aluminium 

Substance Biological 

classification Organism species End point Toxicity (mg/L) 

Skeletonema costatum, SW Growth 

inhibition 

72-h NOEC 

1.04 mg 

Al 

Algae 

Pseudokircheneriella 

subcapitata, FW 

Growth 

inhibition 

96-h NOEC 

< 0.4 mg 

Al 

Aluminium 

ions 

Invertebrates Ceriodaphnia sp., FW Mortality 

8-day NOEC 4.9 mg Al 

 Abbreviations; SW: marine species, FW: fresh water species.

(4) Effects of aluminium accumulated in sediments in discharge water areas 

The report on aluminium assessment by EC and HC (2000) of Canada revealed that 

they conducted toxicity studies of flocs collected in the process of drinking water treatment 

and found no significant toxicity either in studies using micro-organisms or in acute or subacute 

toxicity studies using rainbow trout (fish). In a simulation using the MAM-PEC model, the 

contents of aluminium in sediments after 10 years of accumulation have been calculated 

at 0.000777-0.0349 mg/g. Since this range of simulated contents is substantially smaller than the 

aluminium content in natural soil, aluminium adsorbed to sediments may not exert adverse 

effects on living organisms. 

6.4.2.3 Summary of the risk assessment of aluminium on aquatic organisms 

It is concluded that organisms are quite unlikely to be exposed to harmful levels of aluminium as 

a result of the metal being used for water treatment processes that produce residual aluminium in 

the treated water or flocs. 

6.4.3 Risk assessment of the triiron tetraoxide, PASA, and acrylamide monomers on 

aquatic organisms 

6.4.3.1 Key Study of acute toxicity and chronic toxicity 

Tables 6-9 and 6-10 show the key studies of acute toxicity and chronic toxicity respectively 

extracted from the hazard data those are used for calculation of PNEC values of substances 

employed for Hitachi Ballast Water Purification System. 
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Table 6-9 – Key study of acute toxicity of triiron tetraoxide, PASA, and acrylamide monomers 

Test 

substance 

Biological 

classification Organism species End point Toxicity (mg/L) 

Algae n.a. n.a. No data 

Invertebrates n.a. n.a. No data 

Triiron 

tetraoxide 

Fish Leuciscus idus, FW Mortality 

48-h LC0

* > 1,000 

Algae n.a. n.a. No data 

Invertebrates Ceriodaphnia dubia, 

FW 

Mortality 

48-h LC50

218 

Girella punctata, SW Mortality 

48-h LC50

840 

PASA 

Fish 

Oryzias latipes, FW Mortality 

48-h LC50

180 

Algae Pseudokirchneriella 

subcapitata, FW 

Growth inhibition 

72-h EC50

33.8 

Mysidopsis bahia, SW Mortality 

96-h LC50

78 Invertebrates 

Daphnia magna, FW Swimming 

inhibition 

48-h EC50

98 

Acrylamide 

monomers 

Algae Danio rerio, FW Mortality 

96-h LC50

59 

 Abbreviations: SW: marine species, FW: fresh water species, n.a.: not available *

This evaluation is using LC0 in which no lethality occurs, because this evaluation stands safer value than 

using LC50.

Table 6-3 – Key study of chronic toxicity of triiron tetraoxide, PASA, and acrylamide monomers 

Substance Biological 

classification Organism species End point Toxicity(mg/L) 

Algae n.a. n.a. No data 

Invertebrates n.a. n.a. No data 

Triiron 

tetraoxide 

Fish n.a. n.a. No data 

Algae n.a. n.a. No data 

Invertebrates n.a. n.a. No data 

PASA 

Fish Salvelinus namaycush, 

FW 

Mortality 

30-day NOEC 75 

Algae Pseudokirchneriella 

subcapitata, FW 

Growth 

inhibition 

72-h NOEC 

16 

Invertebrates Mysidopsis bahia, SW Mortality 

28-day NOEC 2.04 

Acrylamide 

monomers 

Fish n.a. n.a. No data 

Abbreviations; SW: marine species, FW: fresh water species, n.a.: not available 

6.4.3.2 Derivation of predicted no-effect concentration (PNEC) 

The PNEC values for triiron tetraoxide, PASA and acrylamide monomers are derived based on 

hazard data (see Tables 6-9 and 6-10). These values were used in the Basic Approval 

(Table 6-11, the details are described in section 8.3.6.3 in the application of Basic Approval). 
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Table 6-4 – PNECs for triiron tetraoxide, PASA and acrylamide monomers 

Substance Toxicity 

(mg/L) 

Assessment 

factor 

PNEC 

(mg/L) 

Triiron 

tetraoxide 48-h LC0 (acute) > 1,000 1,000 > 1 PNECshort

48-h LC50 (acute) 180 1,000 0.18 PNECshort

PASA 30-day NOEC 

(chronic) 75 100 0.75 PNEClong 

96-h LC50 (acute) 59 1,000 0.059 PNECshort Acrylamide 

monomers 28-day NOEC 

(chronic) 2.04 100 0.02 PNEClong 

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

Table 6-5 shows the analytical results of treated water, which are examined and stated in 

section 4, and the predicted discharge concentrations of Active Substances. As for triiron 

tetraoxide, PASA and acrylamide monomers, PNEC values stated in section 6.4.3.2 are used for 

risk assessment. 

Table 6-5 – Analysis results and PECs 

 (Unit: mg/L) 

Substance Analysis result 

(Detection limit) PEC 

Triiron tetraoxide N.D (0.01) <0.01 

Aluminium 0.022 0.022 

PASA N.D (0.1) <0.1 

Acrylamide monomers N.D (0.0001) <0.0001 

6.4.3.4 Assessment for triiron tetraoxide, PASA and acrylamide monomers by PEC/PNEC 

ratio 

As shown in Table 6-13, PEC/PNEC ratio is lower than 1.0 for all these three Active Substances. 

Therefore, there is virtually no risk to aquatic organisms from these three Active Substances 

related to this system. 

Table 6-6 – PEC/PNEC ratio for triiron tetraoxide, PASA and acrylamide monomers 

Substance PEC (mg/L) PNEC (mg/L) PEC/PNEC 

ratio 

Triiron tetraoxide < 0.01 > 1 < 0.01 

PASA < 0.1 0.18* < 0.56 

Acrylamide monomers < 0.0001 0.02 < 0.005 

6.5 Establish the maximum allowable discharge concentration 

Considering the PNEC values calculated in section 6.4.3.2, assessment reports evaluated by 

international bodies and governmental bodies, and dosage concentration of each substance, the 

maximum allowable discharge concentration in the ballast water is established. 
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The substances employed in the Hitachi Ballast Water Purification System forming floc which 

will be collected virtually all as flocs, may remain in the ballast water in minute amounts with 

taking into account mechanism of Hitachi Ballast Water Purification System. The amounts of 

each substance remaining in ballast water will not cause any risks under good operating 

conditions. The maximum allowable discharge concentration can be used as a kind of indicative 

value, in case of trouble, to estimate the performance of the system. 

6.5.1 Establishing the maximum allowable discharge concentration 

6.5.1.1 Aluminium 

(1) Environmental criteria for aluminium 

It is practical to manage the total concentration of dissolved monomeric aluminium and 

particulate aluminium for risk management with respect to human species and aquatic organisms. 

In the United States and Canada, relevant water quality criteria have been established, but there 

are no criteria in Japan and the United Kingdom (Table 6-14). 

Table 6-7 – Criteria for aluminium in water 

Country Environmental Criteria Notes 

Canada 0.074 mg/L 

Minimum criterion for fresh water. 

Aluminium is not expected to be 

toxic in the natural marine 

environment. 

USA 

CMC: 0.75 mg/L 

(Criteria Maximum Concentration) 

CCC: 0.084 mg/L 

(Criteria Continuous Concentration) 

Both criteria are freshwater criteria. 

No criteria for seawater. 

UK n.a. - 

Japan n.a. - 

n.a.: no established criteria 

(2) Establishing the maximum allowable discharge concentration 

The maximum allowable discharge concentration for aluminium is calculated on the basis of 

Canada’s 0.074 mg/L, which is the strictest criterion stated in the above Table 6-14. 

At a background concentration of 0.074 mg/L, the maximum allowable discharge concentration 

of aluminium is 0.22 mg/L according to the MAM-PEC (VER. 1.6 model) simulation 

(CERI, 2008e). The default commercial harbour of the MAM-PEC model is half the size of 

Rotterdam Port, and other conditions were used without change. 

Considering this simulation, at a background concentration less than 0.074 mg/L, it may be clear 

that the calculated result of MAM-PEC is to be less than 0.074 mg/L in the case of an emission 

load of 0.22 mg/L. On the other hand, at a background concentration larger than 0.074 mg/L, 

aquatic organisms living in the area are expected to have some tolerance to such concentrations 

of aluminium. In this case, the result calculated with MAM-PEC is less than the background 

concentration (larger than 0.074 mg/L) when the emission load is 0.22 mg/L, so it is concluded 

that the discharged ballast water has little impact on the aquatic environment. Considering all of 
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the above, the maximum allowable discharge concentration of aluminium in all situations 

is 0.22 mg/L. 

6.5.1.2 Iron 

Iron is one of the most abundant metals in the Earth’s crust and is found in natural fresh waters at 

levels ranging from 0.5 to 50 mg/L. Iron is known as an essential element in human and other 

organisms’ nutrition and there is no data on biotoxic forms of iron. Therefore, it is difficult to 

establish the maximum allowable discharge concentration from an ecotoxicity point of view as 

specified in Metals Environmental Risk Assessment Guidance (UK, International Council of 

Mining & Metals). In Hitachi Ballast Water Purification System, triiron tetraoxide is added as 

slurry and NOT a solution, so that dissolution of iron ions into either ballast water or the 

ecosystem may not occur. Therefore, the maximum allowable discharge concentration of iron has 

been established as 30 mg/L. 

6.5.1.3 PASA 

Table 6-11 shows the PNEC of PASA as 0.18 mg/L and the maximum allowable discharge 

concentration of PASA can be established according to the PNEC value. According to water 

quality guidelines of Canada’s CCME, the US EPA and similar bodies in other countries, dilution 

may be considered because, for the most part, the immediate concentration of substances at the 

discharge point will not be an adequate representation of the concentration of the substance in the 

water body as a whole. For instance, for the most part, aquatic life will not be exposed to the 

concentration of the substance in the pipe but rather to the receiving waters mixed with effluent. 

There is no simulation model to examine dilution similar to MAM-PEC, and which is specialized 

for a macromolecular organic compound such as PASA, so an alternative approach is considered 

such as the use of dilution factors. Canada’s CCME has established a framework of Effluents 

Discharge Objectives considering dilution factors. For lakes and enclosed bays, the default 

dilution factor is a maximum of 1 in 10. Following this framework as an example, it is concluded 

that the maximum allowable discharge concentration of PASA is 1.8 mg/L. 

6.5.1.4 Acrylamide monomers 

Table 6-11 shows the PNEC of acrylamide monomers to be 0.02 mg/L. Some parameters 

required to simulate the discharge load by MAM-PEC are unclear, so that a dilution factor 

of 10 may be applied as for PASA. Thus calculated, the maximum allowable discharge 

concentration of acrylamide monomers is 0.2 mg/L. 

6.6 Conclusion on risk to the aquatic environment 

PAC and PASA are materials used in drinking water treatment plants, so these risk assessments 

have been carried out worldwide. Considering that the dosage concentrations of PAC and PASA 

equal to those of drinking water treatment plants, and the gathered data or assessment reports by 

international authorities, it is concluded that PAC and PASA have a low environmental impact. 

Taking into consideration well known data, its abundance in the natural environment, and its 

insolubility in water, triiron tetraoxide has a low environmental impact. 
MEPC 59/2/5 

ANNEX 

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It is known that unpolymerized acrylamide monomers present a toxic liability. However, 

considering the gathered data including the content of acrylamide monomers in PASA, the 

measured concentration of acrylamide monomers in treated water, and the estimated amount 

discharged in ballast water, acrylamide monomers have a low environmental impact as well. 

Each substance can comply with the established maximum allowable discharge concentrations 

taking into account the properties of each substance and the specifications and mechanisms of the 

Hitachi Ballast Water Purification System. It was concluded that this system presents no risk to 

the aquatic environment. 

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