I:\MEPC\61\2.doc 

E

MARINE ENVIRONMENT PROTECTION 

COMMITTEE 

61st session 

Agenda item 2 

MEPC 61/2

9 March 2010

 Original: ENGLISH

HARMFUL AQUATIC ORGANISMS IN BALLAST WATER 

Application for Basic Approval of Techwin Eco Co., Ltd. (TWECO) 

Ballast Water Management System (PurimarTM) 

Submitted by the Republic of Korea 

SUMMARY 

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

the application for Basic Approval of Techwin Eco Co., Ltd. 

(TWECO) Ballast Water Management System (PurimarTM), 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 6 

Related documents: BWM/CONF/36; MEPC 53/24; MEPC 58/23; MEPC 59/2/13 and 

BWM.2/Circ.24 

Introduction 

1 Ballast water management systems, which make use of Active Substances 

or Preparations containing one or more Active Substances, shall be approved by 

the Organization under regulation D-3.2 of the BWM Convention. 

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

Active Substances (G9)", adopted by resolution MEPC.169(57), defines the principal aspects 

to be documented by data or testing (MEPC 57/21, annex 1, paragraph 4.2.1) and some 

basic principles for risk evaluation (MEPC 57/21, annex 1, paragraph 5.3). According to 

section 6 of Procedure (G9), the Organization should evaluate the information provided in the 

application. 

3 According to BWM.2/Circ.24, proposals for approval of ballast water management 

systems that make use of Active Substances are to be submitted to the Marine Environment 

Division of the Organization to be reviewed by the GESAMP-Ballast Water Working Group. 
MEPC 61/2 

Page 2 

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In the meantime, 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 61. 

4 The competent authority in the Republic of Korea has verified the application dossier 

prepared by Techwin Eco Co., Ltd. (TWECO) and believes it to satisfy the data requirements 

of Procedure (G9). 

5 The Republic of Korea therefore submits the non-confidential part of the applicant's 

dossier in the annex of this document to the Organization for evaluation according 

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

the GESAMP-Ballast Water Working Group with the understanding of confidential treatment. 

Action requested of the Committee 

6 The Committee is invited to consider the proposal for approval and decide as 

appropriate. 

*** 
MEPC 61/2 

Annex, page 1 

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ANNEX 

NON-CONFIDENTIAL INFORMATION ON TECHWIN ECO CO., LTD. (TWECO) BALLAST 

WATER MANAGEMENT SYSTEM (PurimarTM) 

Contents 

LIST OF ABBREVIATIONS 

1 INTRODUCTION 

1.1 History of TWECO’s ballast water management system development 

1.2 Terms and definitions 

1.3 Facility description of PurimarTM system 

1.3.1 Filter 

1.3.2 Electrolizer 

1.3.3 Neutralization unit 

1.3.4 Monitoring and control system 

2 GENERAL 

2.1 Legal provision 

2.2 Principles of acceptability 

2.3 Submission of an application for Basic Approval 

2.4 Confidentiality and data protection 

2.5 Test methods 

2.5.1 Sampling 

2.5.2 Efficacy testing 

2.5.3 Chemical analysis 

2.5.4 Whole Effluent Toxicity (WET) testing 

2.6 Alternatives to testing 

2.7 Procedures and timelines 

3 DATASETS REQUIRED IN THE APPLICATION 

3.1 Identification of Preparation, Active Substances and Relevant Chemicals 

3.1.1 Preparation 

3.1.2 Active Substance 

3.1.3 Relevant Chemicals 

3.1.4 Other Chemical (sodium thiosulfate) 

3.2 Results of efficacy testing 

3.2.1 Preliminary experiments for the system application 

3.2.2 Land-based test run for the system confirmation 

3.3 Results of chemical analysis (Relevant Chemicals) 

3.4 Data on effects on aquatic plants, invertebrates and fish, and other Biota, including 

sensitive and representative organisms 

3.4.1 Whole Effluent Toxicity (WET) test for the evaluation of acute and chronic aquatic 

toxicity 

3.4.2 Acute and chronic aquatic toxicity of Active Substance, Other Chemical and 

Relevant Chemicals 

3.4.3 Endocrine disruption 

3.4.5 Bioavailability/biomagnification/bioconcentration 

3.4.6 Food web/population effects 
MEPC 61/2 

Annex, page 2 

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3.5 Data on mammalian toxicity 

3.6 Data on environmental fate and effect under aerobic and anaerobic condition 

3.6.1 Modes of degradation (Biotic; Abiotic) 

3.6.2 Bioaccumulation, partition coefficient, octanol/water partition coefficient 

3.6.3 Persistence and identification of the main metabolites in the relevant media 

3.6.4 Reaction with organic matter 

3.6.5 Potential physical effects on wildlife and benthic habitats 

3.6.6 Potential residues in seafood 

3.6.7 Any known interactive effects 

3.7 Physical and chemical properties 

3.8 Analytical methods at environmentally relevant concentrations 

4 USE OF THE ACTIVE SUBSTANCE OR THE RELEVANT CHEMICAL 

5 MATERIAL SAFETY DATA SHEETS 

5.1 Hazard classification of Active Substance 

5.2 Hazard classification of Relevant Chemicals 

5.2.1 DBPs 

5.2.2 Hydrogen gas 

5.3 Hazard classification of Other Chemical 

6 RISK CHARACTERIZATION 

6.1 Screening for Persistence, Bioaccumulation and Toxicity 

6.2 Evaluation of the treated ballast water 

6.3 Risk characterization and analysis 

6.3.1 Reaction with organic matter 

6.3.2 Characterization of degradation route and rate 

6.3.3 Prediction of discharge and environmental concentrations 

6.3.4 Assessment of potential for bioaccumulation 

6.3.5 Effects assessment 

6.3.6 Effects on aquatic organisms 

6.3.7 Effects on sediment 

6.3.8 Comparison of effect assessment with discharge toxicity 

7 RISK ASSESSMENT 

7.1 Risk to safety of ship 

7.1.1 Corrosion 

7.1.2 Fire and explosion (formation of gases) 

7.1.3 Storage and handling of the substances 

7.2 Risks to human health 

7.2.1 Risk characterization 

7.3 Risks to the aquatic environment 

8 ASSESSMENT REPORT 

8.1 Overview of data and endpoint 

8.2 Quality of the test reports 

9 REFERENCES 

10 APPENDICES 
MEPC 61/2 

Annex, page 3 

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LIST OF ABBREVIATIONS 

For the purpose of this report, any abbreviations used are the same as specified in 

Procedure (G9), as follows: 

Abbreviation Description Abbreviation Description 

% Percent mN/m millinewton per metre 

°C Celsius degree mPa millipascal 

AS Active Substance MS Matrix Spikes 

ASTM American Society for Testing and 

Materials MSD Matrix Spikes Duplicates 

ATS Agency for Technology and 

Standards MSDS Material Safety Data Sheets 

BCF Bioconcentration factor mV Millivolts 

BPA Busan Port Authority N.D Not detected 

Br2 Bromine N/A Not available, Not applicable 

BWMS Ballast Water Management 

System Na2S2O3 Sodium thiosulfate 

CAS Chemical Abstract Service NaOCl Sodium hypochlorite 

CASRN Chemical Abstracts Service 

Registry Number NELAP National Environmental Laboratory 

Accreditation Program 

CFU Colony Forming Unit NFRDI National Fisheries Research & 

Development Institute 

Cl- Chloride ion NIOZ Netherlands Institute for Sea 

Research 

Cl2 Chlorine NOAEL No Observed Adverse Effect Level 

CO2 Carbon dioxide NOEC No Observed Effect Concentration 

Conc. Concentration NOEL No Observed Effect Level (used 

interchangeably with NOAEL) 

COPC Chemical(s) of Potential Concern NPOC Non-purgeable organic carbon 

CSA Catalytic Stable Anode O&M Operational/Maintenance 

DAPI 6-diamidino-2-phenylindole OBr- Hypobromite ion 

DAU Dong-A University OCl- Hypochlorite ion 

DBPs Disinfection By-products OECD Organization for Economic 

Co-operation and Development 

DC Direct Current OIT Operator Interface Terminal 

DGPS Differential Global Positioning 

System OPPTS Office of Prevention, Pesticides, 

and Toxic Substances 

DO Dissolved Oxygen ORP Oxidation Reduction Potential 

DOC Dissolved Organic Carbon OSHA Occupational Safety and Health 

Administration 

DPD N,N-diethyl-p-phenylenediamine Pa Pascal 

dph days post-hatch PBT Persistence, Bioaccumulation, and 

Toxicity 

DQOs Data Quality Objectives PBT 

profiler 

Persistent, Bioaccumulative, and 

Toxic Profiler 
MEPC 61/2 

Annex, page 4 

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Abbreviation Description Abbreviation Description 

dynes/ 

cm dynes per centimetre PE Polyethylene 

EC50

Effective concentration of 

substance that causes 50% of 

maximum response 

PEC Predicted Environmental 

Concentrations 

ECR Engine Control Room PEL Permissible Exposure Limit 

EDCs Endocrine Disrupting Chemicals PFD Process Flow Diagram 

EM Excellent Materials pKa Dissociation Constant 

EPI Environmental Sustainability Index PLC Programmable Logic Controller 

FRP Fibre reinforced plastic PM Phase Rotation Monitor 

g/day gram per day PNEC Predicted No-Effect 

Concentrations 

G/T Gross Tonnage POC Particulate Organic Carbon 

GESAMP

-BWWG 

Joint Group of Experts on the 

Scientific Aspects of Marine 

Environmental Protection–Ballast 

Water Working Group 

PPE Personal Protective Equipment 

H+ Hydrogen ion ppm Parts per million 

H2 Hydrogen gas PQL Practical Quantification Limit 

HAAs Haloacetic acids PSU Practical Salinity Units 

HAMP Harmful Aquatic Microorganisms 

and Pathogens QAPP Quality Assurance Project Plan 

HANs Haloacetonitriles QMP Quality Management Plan 

HOBr Hypobromous acid R&D Research and development 

HOCl Hypochlorous acid RC Relevant Chemicals 

hPa hecto-Pascal RDL Required Detection Limits 

HPhs Halophenols RfD Reference Dose 

HSDB Hazardous Substances Data Bank RPD Relative Percent Difference 

IARC International Agency for Research 

on Cancer 

RPhrases Risk Phrases 

IC Inorganic carbon SB Sterile bottles 

ICSC International Chemical Safety 

Cards SCGE Single Cell Gel Electrophoresis 

IMO International Maritime 

Organization SCR Silicon Controlled Rectifier 

IPCS International Programme on 

Chemical Safety SCWO Supercritical water oxidation 

ISO International Organization for 

Standardization SGPT Serum Glutamate-Pyruvate 

Transaminase 

IUCLID International Uniform Chemical 

Information Database SIDS Screening Information Dataset 

kg/m3 kilogram per cubic metre SOPs Standard Operating Procedures 

KHNP Korea Hybrid & Nuclear Power Co. 

Ltd. 

SPhrases Safety Phrases 

Koc Organic Carbon Partition 

Coefficient SP-IDC Shipping & Port-Internet Data Centre 
MEPC 61/2 

Annex, page 5 

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Abbreviation Description Abbreviation Description 

KOLAS Korea laboratory accreditation 

scheme SST Stainless Steel 

Kow Octanol/Water Partition Coefficient SVOCs Semi-Volatile Organic Compounds 

L/kg Litre per kilogram TCA Trichloroacetic acid 

L/min Litre per minute THMs Trihalomethanes 

LC50 Lethal Concentration 50 TOC Total Organic Carbon 

LD50

Lethal Dose for 50% of test 

population TOXNET Toxicology Data Network 

LEL Lower Explosive Limit TRO Total residual oxidants 

M Meter TSS Total Suspended Solids 

mA Milliampere TWECO Techwin Eco 

MAMPEC 

Marine Antifoulant Model to 

Predict Environmental 

Concentrations 

UCL Upper Confidence Level 

MBDC Marine Bio-industry development 

centre UI User Interface 

MDL Minimal Detection Limit US EPA United States Environmental 

Protection Agency 

MEPC Marine Environment Protection 

Committee Vdc Volts of continuing current 

mg/kg 

bw milligram per kilogram body weight W/H Wheel House 

mg/kg-d milligram per kilogram per day WET Whole effluent Toxicity 

mg/L milligram per litre WHO World Health Organization 

MLTM Ministry of Land, Transport and 

Maritime Affairs wt % Weight per cent 

Mm2/s square millimetre per second μg/L microgram per litre 

mmHg millimetre of mercury μg/ml microgram per millilitre 

mN/m millinewton per metre μM micro-molarity 

mPa millipascal μS/cm microsiemens per centimeter 

1 INTRODUCTION 

1.1 Ballast water management system ("PurimarTM") 

The PurimarTM Ballast Water Management System (or simply PurimarTM System) developed 

by Techwin Eco (TWECO) is a system utilizing proven technology to filter out, oxidize and 

disinfect all harmful aquatic organisms and pathogens present in the ballast water with 

Sodium Hypochlorite. 

The system testing of the PurimarTM System was carried out through the two-step process. 

The preliminary operating experiments for the system application were performed by using 

the pilot-scale test set-up with a flow rate of 5 m3

/hr and the supplementary laboratory-scale. 

After accomplishing the preliminary operating experiments, the land-based test runs were 

executed by using the full-scale PurimarTM system with a capacity of 250 m3

/hr installed on 
MEPC 61/2 

Annex, page 6 

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the TWECO test barge at two different sites with more than 10 PSU difference in salinity – 

seawater test in Busan Port (>32 PSU) and brackish water test in Nakdong River or similar 

estuary (3~32 PSU). At each operating event of the land-based test run, water quality 

parameters of influent water were measured immediately on site and at the laboratory. Only 

those events fulfilled the requirements of Guidelines (G8). Water quality was taken into 

further consideration for the test cycles of the land-based test run.

1.2 Terms and definitions 

For the purpose of this report, terms and definitions are the same as specified 

in Procedure (G9), and are therefore not repeated here, except for the following which are 

specific to this report: 

- "Pre-treated Water" is seawater treated by only a filtration system, which is a 

pre-treatment part of the PurimarTM System. 

- "Treated Water" is seawater treated by the PurimarTM System.

- "Ballast Water Discharge" is the treated ballast water that has passed 

through the neutralization unit during deballasting. The neutralization is a 

process for further decrease of the total residual oxidants (TRO) concentration 

if required before discharge at deballasting. 

- "Active Substance" refers to the total residual oxidants (TRO) generated in 

treated ballast water from the electrolysis-based chlorination process of the 

PurimarTM System, which is completely responsible for inactivating all harmful 

aquatic organisms and pathogens (HAMP) present in the ballast water. Active 

Substances are discussed in detail in section 3.1.2. 

- "Preparation" has the same meaning as "Active Substance" for the PurimarTM

System as it does not intentionally add any preparation besides 

chlorination.This preparation is discussed in detail in section 3.1.1. 

- "Relevant Chemicals" refer to the chlorination by-products formed by the 

reaction of chlorine with natural organic matter. Relevant Chemicals are 

discussed in section 3.1.3. 

The above interpretations of the definitions contained in Procedure (G9) mean that in the 

case of the PurimarTM System, these terms all refer to the treated ballast water that is 

discharged following the sequence of: 

.1 ballasting; 

.2 treatment, 

.3. voyage; and 

.4 deballasting. 

As have been applied for other electrolysis-based ballast water management systems that 

have been granted Final Approval by MEPC, it is therefore the treated ballast water that is 

considered in this application and thus tested for efficacy, toxicity and content of chemicals. 
MEPC 61/2 

Annex, page 7 

I:\MEPC\61\2.doc 

1.3 Facility description of PurimarTM system 

1.3.1 Filter 

The filter unit can remove particles and organisms having a size of more than 50μm from the 

ballast water, and includes an automatic back-flushing system. In the automatic 

back-flushing system, the self-cleaning system operates to remove foreign materials 

attached to the surface of the filter and always maintains uniform treatment efficiency when 

there is a stoppage phenomenon in the filter due to change in pressure. 

1.3.2 Electrolyzer 

The electrolysis unit has an objective of producing and injecting sodium hypochlorite 

(NaOCl), through electrolysis of ballast water at the time of ballasting. In the ballasting mode, 

a part of seawater divided from the ballast main piping line is electrolyzed and then injected 

to the main piping line again. The PurimarTM System uses the divided seawater in an amount 

less than 1% of the total flow-rate of seawater that flows into the main ballast pipeline. The 

electrolyzer uses the CSA electrode that applies the unique technology of TWECO and is 

designed to be able to control the fouling. 

Hydrogen gas is a by-product generated during the production of sodium hypochlorite. The 

mixed solution of the hypochlorite and the hydrogen gas flows into the hydrogen-hypo 

separation unit immediately after they are produced from the electrolyzer. More than 95% of 

the hydrogen having a low specific gravity is separated from the hydrogen-hypo solution and 

is transmitted by the action of cyclone to the de-gas tank by piping through a small titanium 

orifice at the upper part of the cyclone, and the remaining sodium hypochlorite solution is 

injected into the ballast water main pipeline through the injector. 

1.3.3 Neutralization unit 

The neutralization unit is installed in the PurimarTM System to achieve the objective of 

reducing the residual TRO included in the ballast water to a level that is not harmful to 

humans and natural environment and then discharging it at the time of deballasting. The 

injection point of the neutralizing agent is disposed on the inlet or outlet of the ballast pump 

for the even mixing of the neutralizing agent and the ballast water. The ballast water whose 

neutralization is completed maintains the TRO value of less than 0.1 ppm. 

1.3.4 Monitoring and control system 

The PurimarTM System is designed to enable monitoring and control from any places in the 

ship, from a W/H (Wheel House) to an ECR (Engine Control Room) because the network 

function is possible. The PurimarTM System is also designed to monitor and control the filter 

unit, electrolysis unit (electrolyzer and rectifier), TRO sensor and neutralization unit for the 

optimal full-scale test. The main functions thereof are detailed in the complete confidential 

dossier. 

2 GENERAL 

2.1 Legal provision 

The legal provision for this application is regulation D-3.2 of the International Convention for 

the Control and Management of Ships’ Ballast Water and Sediments, which stipulates that 

ballast water management systems that make use of Active Substances shall be approved 

by the Organization. 
MEPC 61/2 

Annex, page 8 

I:\MEPC\61\2.doc 

During its fifty-third session, the Marine Environment Protection Committee (MEPC) adopted 

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

Substances (G9) through resolution MEPC.126(53). 

This application and the comprehensive testing program that has been conducted by 

TWECO to support it are in full compliance with Procedure (G9). 

2.2 Principles of acceptability 

In accordance with Procedure (G9) and as presented in this report, TWECO has sought to 

meet the principles of acceptability by undertaking comprehensive toxicity testing of ballast 

water treated by the PurimarTM System in system testing, in order to determine if the system 

can be used and under which conditions the potential for harming the receiving environment 

or human health is acceptably low. 

2.3 Submission of an application for Basic Approval 

This application is for Basic Approval. The information in this dossier includes: 

- results of the comprehensive toxicity testing and chemical analysis, as required in 

Procedure (G9); 

- results of the efficacy testing, as required in Guidelines (G8); 

- Quality Assurance Project Plan (QAPP); and 

- technical specifications of the optimized PurimarTM System. 

2.4 Confidentiality and data protection 

TWECO accepts that all items listed in section 2.4 of the GESAMP-BWWG Methodology 

shall not be regarded as confidential once the system and Active Substance are approved.

2.5 Test methods 

The undertaking of comprehensive testing for efficacy and toxicity of the PurimarTM System 

comprises four major tasks: 

.1 sampling (Laboratory, Pilot-scale, and Land-based testing); 

.2 determination of water quality parameters and efficacy testing of the 

samples (Guidelines (G8) testing); 

.3 chemical analysis of the samples (Procedure (G9) testing); and 

.4 whole Effluent Toxicity (WET) testing of the samples (Procedure (G9) 

testing). 

The quality assurance arrangements for the tasks are the subject of a QAPP developed by 

TWECO and Dong-A University (appendix 3). All staff involved in the efficacy and toxicity of 

the PurimarTM System received training in the QAPP and its application to the procedures for 

each test. All test methods were carried out in compliance with the requirements of 

Guidelines (G8) and Procedures (G9). 
MEPC 61/2 

Annex, page 9 

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2.5.1 Sampling 

In the preliminary experiments for the system application, water samples were collected 

during the operation of the pilot-scale test set-up using seawater in Ulsan as source water. 

For the preparation of brackish water samples, source water was diluted with tap water and 

passed through the test set-up. In addition, water samples for supplemental laboratory-scale 

experiments were obtained by adding a sodium hypochlorite solution, generated from the 

electrolysis of 3% NaCl solution, to the filtered commercial sea or brackish water. Every test 

run was performed on two water samples; sequentially, a control (untreated) experiment 

bypassing the filter and disinfection processes were conducted first. 

In the land-based test runs for the system confirmation, water samples were collected during 

the operation of the full-scale PurimarTM System fitted on the TWECO test barge, at the 

Busan Port. At each operating event, water quality parameters of influent water were 

measured immediately on site and at the laboratory of MBDC. Only the event fulfilled 

Guidelines (G8) requirements as the water quality has been taken into further consideration 

for the test cycle of the land-based test run. 

If required in ballast water discharge at deballasting, sodium thiosulfate was added to the 

treated water samples to immediately decrease the total residual oxidants (TRO) 

concentration as a neutralization process. 

An overview of the testing scheme is presented in Table 2.1 and Figure 2.1. (See the 

complete confidential dossier.)

Collection of field samples was undertaken by a joint team of marine biologists and 

environmental engineers from TWECO, NLP and DAU, using standard water sample 

collection methods and in accordance with Guidelines (G8). Standard operating procedures 

(SOPs) were employed to provide consistency and reproducibility of the sampling methods 

used by field personnel, as outlined in the Quality Assurance Project Plan (QAPP). 

Water samples were taken from both the control (untreated) and treatment tanks at two or 

three times of intervals following treatment – at the ballasting (immediately after treatment, 

Day O), at the two days storage (Day 2) or the discharge (deballasting with neutralization 

process, Day 2n), and at the five days after treatment with or without neutralization (Day 5 or 

Day 5n). An overview of the sampling points is presented in Figure 2.2. 
MEPC 61/2 

Annex, page 10 

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Figure 2.2: Sampling points at the pilot-scale test set-up (A) and the 

full-scale PurimarTM System (B) 

Water samples were taken directly into a clean bucket after washing with sample water, 

pre-filtered with 45 μm net to remove large particles and poured into sterile plastic bags to 

prevent possible contamination. The analytical laboratory provided pre-labelled sample 

containers which included the required preservative for each parameter. 

The collected samples were cooled immediately in an ice-box, packed and transported to the 

laboratory test facilities by the field staff from NLP; to MBDC by car within one (1) hour of 

being collected and to SGS by KTX train, and parcel delivery service within five (5) hours. All 

the field and laboratory test facilities prepared written standard operating procedures (SOPs) 

for sample custody, and examples of the sample chain-of-custody form were contained in the 

QAPP. When the samples arrived at the laboratory test facilities, the sample custodian 

received the samples, signed the form, opened the sample coolers, carefully checked the 

contents for evidence of leakage and to verify that samples were kept on ice, and then 

verified that all information on the sample container label were correct and consistent with 

the information on the chain-of-custody form. 
MEPC 61/2 

Annex, page 11 

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Full details of the collection of samples, including their handling and transmission under 

chain of custody for each testing, were contained in the QAPP. 

2.5.2 Efficacy testing 

Assurance of fulfillment of water quality test criteria and bio-efficacy testing was conducted 

by MBDC, based on the quality system of ISO/IEC 17025, in accordance with 

Guidelines (G8). Full details were contained in the QAPP. 

2.5.3 Chemical analysis 

At each sampling event Active Substance (TRO) was measured immediately on site, and the 

samples were then sent to MBDC for further analysis of TRO and SGS for analysis of 

Relevant Chemicals (disinfection by-products; DBPs). 

Active Substance 

Active Substance, in this dossier, is defined as the total of all oxidants present in treated 

water of the PurimarTM System, which are discussed in detail in section 3.1.2. 

TRO level was measured in situ (on the field and test barge) using two different analytical 

procedures, which are as follows: 

- automatic sampling and testing using TRO concentration analyser (CLX Online 

Residual Chlorine Monitor, HF Scientific), installed separately in ballast line and 

deballast stream; and 

- manual testing of water samples using portable Spectrophotometer (Chlorine Pocket 

Photometer, HF Scientific). 

During further analysis of TRO at MBDC, TRO measurements were performed internally by 

the researchers using a Hach DR2800 colorimeter and Hach method 8167. 

All these methods are based on a standard DPD (N,N-diethyl-p-phenylenediamine) 

colorimetric method (equivalent to US EPA METHOD 330.5). The TRO oxidizes triiodide ion 

(I3

-

) to iodine (I2). The iodine and free chlorine react with DPD to form a red solution. The 

colour intensity is proportional to the TRO concentration, which is displayed as the equivalent 

of mg/L as Cl2. 

Relevant Chemicals 

"Relevant Chemicals", in this dossier, is defined to refer to the chlorinated/brominated 

by-products formed by the reaction with natural organic matter. These Relevant Chemicals 

are discussed in detail in section 3.1.3. 

The following items were measured to analyse Relevant Chemicals or a number of DBPs 

from reactions between chlorine and naturally-occurring compounds in the treated water, in 

accordance with Procedure (G9): 

- Bromate (BrO3

-

); 

- Trihalomethanes (THMs) including Trichloromethane (Chloroform), Tribromomethane 

(Bromoform), Chlorodibromomethane and Dichlorobromomethane; 
MEPC 61/2 

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- Haloacetic acids (HAAs) including Monochloroacetic acid, Dichloroacetic acid, 

Trichloroacetic acid, Monobromoacetic acid, Dibromoacetic acid, Tribromoacetic 

acid, Bromochloroacetic acid, Bromodichloroacetic acid and Dibromochloroacetic 

acid;

- Haloacetonitriles (HANs) including Dichloroacetonitrile and Dibromoacetonitrile; 

and 

- Halophenols (HPhs) including Pentachlorophenol. 

The analytical laboratory services for the measurement of DBPs using the discharge water 

samples from the PurimarTM System were carried out by the qualified and accredited 

laboratories under internationally-recognized guidelines (OECD or equivalent) and quality 

system of ISO/IEC 17025. Full details were given in the QAPP. 

2.5.4 Whole Effluent Toxicity (WET) testing 

WET testing was carried out by a joint organization of MBDC and Dong-A University Quality 

Assurance (QA) team, under internationally-recognized guidelines (OECD or equivalent) and 

internationally recognized quality assurance system (GLP). This study aims to assess the 

residual toxicity of whole-effluent ballast water after treatment by the PurimarTM System, in 

accordance with Procedure (G9). The objectives are to analyse the impact of treated ballast 

water on seawater and of brackish water ecosystems to evaluate possible risks to humans 

and other recipients, posed by current and future exposure to ballast water treated by 

the PurimarTM System, and to determine what additional measures might be needed to 

reduce any risks. 

Immediately after verification of field water samples, the water samples were passed through 

the filtering system (pore size 0.45 μm) by using peristaltic pump. After measurements of pH, 

temperature, salinity, and dissolved oxygen (DO), test substances prepared from the treated 

water samples were subjected to the concentration-response tests, which consisted of 

control dilution water (0%) and a minimum of three concentrations commonly selected to 

approximate a geometric series, i.e. 100%, 75%, 50%, 25% and 12.5%. With respect to the 

formulation of the dosing preparation, commercial natural seawater was used as a diluent. 

As the test substances prepared from the untreated ballast water samples were likely to be 

non-toxic, the single concentration (undiluted, 100% solution) was subjected to the limit test. 

All WET tests were initiated simultaneously within 6 hours of sampling. For some tests which 

are necessary for the renewal of test substances, samples were kept in a secure storage 

(locked refrigerators) where they were maintained at 4 degrees Celcius. 

In accordance with the Procedures (G9), a number of different tests were required, as listed 

below: 

- Growth Inhibition Test with Microalgae; 

- Survival Test with Rotifer; 

- Survival Test with Larval Fish; 

- Reproduction Test with Rotifer; and 

- Growth Test with Larval Fish. 
MEPC 61/2 

Annex, page 13 

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Each test was the subject of a specific Study Plan, as contained in appendix 3 of the QAPP. 

All the test methods were carried out in compliance with the requirements of Procedure (G9) 

and all staff involved in the WET testing received training in the QAPP and its application to 

the Study Plan for each test. 

2.6 Alternatives to testing 

As outlined in section 1.1 of this annex, consistent with the approach that has been applied 

for other electrolysis-based ballast water management systems that have been granted Final 

Approval by the MEPC, it is the treated ballast water that is considered in this application and 

thus tested for efficacy, content of chemicals and toxicity. Accordingly, each testing was 

undertaken with the PurimarTM effluent, using test methods that comply with Guidelines (G8) 

and Procedure (G9). 

However, the GESAMP-BWWG's review of the other BWMS submissions, requested that 

data be provided on chemicals of Active Substance and Relevant Chemicals. TWECO has 

not undertaken direct toxicity testing of those chemicals. Rather, the data has been collected 

from existing literature, and these are presented and interpreted in sections 3.4 and 3.5 of 

this annex. 

2.7 Procedures and timelines 

The submission of this application is in accordance with the procedures and timelines of 

Procedure (G9). 

3 Datasets required in the application 

All results presented in this section are taken from the raw data sheets contained in 

appendices 1, 4, and 5. 

3.1 Identification of Preparation, Active Substances and Relevant Chemicals 

3.1.1 Preparation 

"Preparation" means any commercial formulation containing one or more Active Substances 

including any additives. 

As outlined above, the PurimarTM System does not involve the formulation of any Preparation 

for carriage on board the ship for use in the BWMS. Rather, the Active Substance chlorine is 

generated on board as required. 

Strictly speaking then, TRO is the Active Substances of relevance to the PurimarTM System. 

The by-products of chlorination are collectively referred to as Disinfection By-Products 

(DBPs), and may be considered as Relevant Chemicals. 

However, as stated above, for the purposes of this application and the whole effluent testing 

that has been conducted to support it, "Preparation", "Active Substance" and "Relevant 

Chemicals", as well as "Ballast Water Discharge", all have the same meaning. This "whole 

effluent" approach has been adopted for other oxidant-based ballast water management 

systems that have been granted Final Approval by MEPC. 

Nevertheless, relevant data as required by Procedure (G9) are provided below for Active 

Substance and Relevant Chemicals. 
MEPC 61/2 

Annex, page 14 

I:\MEPC\61\2.doc 

3.1.2 Active Substance 

The general definition of "Active Substance" is a substance or organism, including a virus or 

a fungus that has a general or specific action on or against harmful aquatic organisms and 

pathogens. 

The key method of the PurimarTM system for inactivating harmful aquatic organisms and 

pathogens is the use of direct chlorination with electrolysis of seawater. Seawater is passed 

through electrolytic cells (electrolyzers) which are comprised of a cathode and a CSA®

anode. The primary cell reactions occurring in the electrochemical generation process in 

seawater are as follows: 

At the anode: Cl-

 + Cl- → Cl2 + 2e- (1) 

 2H2O → 4H+

 + O2 + 4e- (2) 

 Br-

 + Br- → Br2 + 2e- (3) 

At the cathode: 2H2O + 2e-

 → H2 + 2OHIn the seawater: Cl2 + 2OH-

 + 2Na+ → NaOCl + H2O + NaCl 

At the CSA® anode, reaction (1) occurs mainly in seawater. However, in fresh water having a 

very low chloride concentration, reaction (2) may occur such that the efficiency of reaction (1) 

may decrease. 

Moreover, the use of reaction (2) as a controllable biocide is not suitable because a clear 

mechanism for the electrochemical intermediate product (OH*) is not established. 

Also, seawater contains 50~70 ppm of bromide ion which forms bromine as shown in 

reaction (3) in a manner similar to chloride ion. 

As can be seen in Figure 3.1, sodium hypochlorite (NaOCl) produced in the electrolyzer is 

present as chlorine (Cl2), hypochlorite ion (OCl-

) and hypochlorous acid (HOCl) depending on 

the pH of seawater. 

 Cl2 + H2O ↔ HOCl + H+

 + Cl-

 HOCl ↔ OCl-

 + H+

At the pH of seawater (typically ranges from 7.5-8.4), the solution generated by the 

PurimarTM System will consist of a near equal mixture of hypochlorous acid and hypochlorite 

ion. 

Also, bromine is present as bromine (Br2), hypobromous acid (HOBr) and hypobromite ion 

(OBr-

) depending on the pH of seawater in a manner similar to chlorine, in which 

hypobromous acid (HOBr) may be produced from the reaction of hypochlorous acid (HOCl) 

with bromide ion (Br-). 

 Br2 + H2O ↔ HOBr + H+

 + Br-

 HOBr ↔ OBr-

 + H+

 HOCl + Br- → HOBr + ClAt the pH of seawater, the solution generated by the PurimarTM System will also consist of a 

mixture of hypobromous acid and hypobromite ion, with a slightly greater proportion of the 

mixture existing as hypobromous acid. 
MEPC 61/2 

Annex, page 15 

I:\MEPC\61\2.doc 

Thus, at the outlet of the electrochemical generator, the seawater contains a mixture of 

chemicals produced at both the anode and cathode. The electrochemical process results in 

the formation of the actual disinfecting agents – hypochlorous acid in equilibrium with 

hypochlorite ion and hyprobromous acid in equilibrium with hypobromite ion – and hydrogen 

gas produced as a by-product. During the electrochemical process a small amount of caustic 

(OH-

) is also produced, which is effectively neutralized within the cell and causes no apparent 

increase in the pH of treated ballast water. 

Further, chlorine and bromine can undergo reactions with ammonia naturally present in 

seawater, and may result in the formation of low concentrations of chloramines and 

bromines. Chloramine and bromine are important to discuss in disinfection chemistry 

because these are also considered disinfectants. However, they are less effective 

disinfectants (i.e. weak oxidants) and the amount of disinfection attributed to chloramine and 

bromine is not considered relevant. The amount of chloramine and/or bromine potentially 

formed is related to the amount of ammonia present, amount of oxidant present, reaction 

time, and pH of the water treated. The amount of chloramine and bromine formed during use 

of the PurimarTM System is expected to be insignificant because of the neutral pH at which 

treatment is occurring and the long reaction time required for their formation. 

The common factor in all of these chemical species is that they are considered oxidants, and 

due to the difficulty in measuring each chemical species individually in a complex water 

sample, the term Total Residual Oxidants (TRO) is used to include all of these oxidants when 

present in a sample and is referred as "Active Substance". 

Therefore, in this dossier, TRO is used to describe the total of all oxidants present in water 

treated by the PurimarTM System. The chemical methods used for analysing TRO often state 

that the measurement is calculated as mg Cl2/L. However, these methods include all of the 

oxidants present in a water sample as mentioned above, not just Cl2. All concentrations of 

TRO are given as equivalent chlorine in this application dossier for reasons of better 

comparability. 

During the preliminary and land-based test runs of the PurimarTM System, pre-filtration of the 

ballast water incorporated as part of the test set-up removed bigger zooplankton and showed 

excellent results in eliminating viable organisms present in the water before treatment at a 

TRO concentration of 3 mg/L TRO. The existing results of efficacy testing are presented in 

section 3.2.

Actually, in the PurimarTM System, the Active Substance is generated at a concentration of 

less than 1,000 mg/L prior to injection into the ballast pipelines. As the biocide solution enters 

the ballast system, it is diluted to no more than 10 mg/L TRO. Because the Active Substance 

is generated in situ, it is not stored on board the vessel except in the ballast tanks at 

expectable maximum concentrations <10 mg/L TRO. 

3.1.3 Relevant Chemicals 

According to Procedure (G9), "Relevant Chemicals" mean transformation or reaction 

products that are produced during the treatment process or in the receiving environment and 

may be of concern to the aquatic environment and human health when discharged. 

Trihalomethanes (THMs), Haloacetonitriles (HANs), Halophenols (HPhs) and 

Haloacetic acids (HAAs)

Disinfection of water with chlorine-based disinfectants can result in the formation of various 

by-products. Chlorine is very reactive towards natural organic matter, leading to the formation 
MEPC 61/2 

Annex, page 16 

I:\MEPC\61\2.doc 

of several by-products. While trihalomethanes (THMs) are the major compounds formed, 

other by-products are of concern due to their possible toxicity towards aquatic organisms: 

haloacetonitriles (HANs), halophenols (HPhs) and haloacetic acids (HAAs). 

The type and relative amounts of the chlorination by-products vary with the organic content 

of the water and also with the inorganic species present. Hence, the chlorination of waters 

containing ammonia, bromide and organic matter, leads to competitive reactions with 

chlorine. Chlorine preferentially reacts with ammonia until monochloramine formation is 

complete. However, at high bromine concentrations and low ammonia levels, bromine may 

be formed before the break-point; this is often the case in marine waters. Thus, the bromine 

and chlorine species are therefore in competition to react with the organic matter, either as 

oxidizing or as substituting agents. As a consequence, brominated compounds may be 

formed. 

Bromate 

Formation of bromate (BrO3

-

) may occur during the electrochemical treatment process. 

The following equation (1) shows the reaction occurring at the electrode: 

 Br-

 + 3H2O → BrO3

-

 + 6e- (1) 

The amount of bromate formed will vary based on the amount of bromide ion present in the 

incoming seawater and the overall production rate of the treatment system. 

Early work by Kretzschmar and by Bray enables us to postulate the following alternative 

reactions: 

6Br-

 → 3Br2 + 6e- (2) 

2Br2 + 2OH- → 2HBrO + 2Br-

 (3) 

Br2 + 2OH- → BrO-

 + H2O + Br- (4) 

2HBrO + BrO- → BrO3

-

 +2HBr (5) 

Which is a sequence similar to that postulated for chlorate formation although reaction (5) 

has a rate constant some two orders of magnitude greater than that of the analogous 

reaction with chlorine-containing species, and reactions (3) and (4) do not proceed as rapidly. 

Other potential mechanisms for bromate ion formation include the secondary reaction of 

HOCl with bromide ion to form hypobromite ion, which can further react to form bromate ion: 

HOCl + Br- → HOBr + Cl-

 (6) 

As mentioned previously, these reactions are dependent on the concentration of available 

bromide ion and pH. At the concentrations of oxidant produced in the electrolytic cell, the 

formation of bromate ion through these secondary pathways is expected to be minimal. 

Hydrogen gas 

Hydrogen (H2) is formed as a by-product of seawater electrolysis, as can be seen in reaction 

occurring at the cathode. Due to the explosive properties of hydrogen gas, allowing it to 

accumulate in the ballast tanks would create an unsafe situation. 

In the PurimarTM System, the hydrogen produced during the electrochlorination process is 

separated immediately upon exit from the electrolytic cell using a cyclone separation device
MEPC 61/2 

Annex, page 17 

I:\MEPC\61\2.doc 

and is not allowed to enter the ballast water piping. As the formed hydrogen is not present in 

treated ballast water, it is not evaluated in regards to aquatic toxicity. 

The separated hydrogen gas is diluted to less than 1% hydrogen by air blowers and vented 

to the air outside the ship. The lower explosive limit (LEL) for hydrogen is 4% and the 

operating limitations of the system provide a four-fold safety factor. Therefore, hydrogen gas 

in the air is not considered relevant for the assessment of human health risks. 

Therefore, the system testing of the PurimarTM System evaluated treated water samples 

collected at different time intervals for Relevant Chemicals. The following items were 

measured: 

- Bromate (BrO3

-

); 

- Trihalomethanes (THMs) including Trichloromethane (Chloroform), 

Tribromomethane (Bromoform), Chlorodibromomethane and 

Dichlorobromomethane; 

- Haloacetic acids (HAAs) including Monochloroacetic acid, Dichloroacetic acid, 

Trichloroacetic acid, Monobromoacetic acid, Dibromoacetic acid, Tribromoacetic 

acid, Bromochloroacetic acid, Bromodichloroacetic acid and Dibromochloroacetic 

acid;

- Haloacetonitriles (HANs) including Dichloroacetonitrile and Dibromoacetonitrile; 

and 

- Halophenols (HPhs) including Pentachlorophenol. 

Tables 3.9, 3.10, 3.11, 3.12, and 3.13 (see the complete confidential dossier) present data 

from samples collected immediately after treatment (Day 0), two days after treatment (Day 2) 

and five days after treatment (Day 5). The samples collected on Day 2n and Day 5n were 

analysed after neutralization with sodium thiosulfate. 

Bromate and HPhs were not detected. Two THMs (tribromomethane and 

chlorodibromomethane), nine HAAs (monochloroacetic acid, dichloroacetic acid, 

trichloroacetic acid, monobromoacetic acid, dibromoacetic acid, tribromoacetic acid, 

bromochloroacetic acid, bromodichloroacetic acid, and dibromochloroacetic acid), and two 

HANs (dichloroacetonitrile, dibromoacetonitrile) were detected, at a maximum total THM 

concentration of 0.394 mg/L (test cycle P-4(1) on Day 5, Table 3.11), HAA concentration 

of 0.109 mg/L (test cycle P-3 on Day 5, Table 3.10), and HAN of 0.0517 mg/L (test cycle 

P-4(1) on Day 2 following neutralization, Table 3.11), respectively. 

3.1.4 Other Chemical (sodium thiosulfate) 

The PurimarTM System chlorinates ballast water during uptake – at the start of the voyage, 

and the ballast water oxidant demand dramatically reduces the resultant residual oxidant 

level. It is therefore unlikely that there will be any residual oxidants remaining in the ship's 

ballast after a typical voyage of several days to weeks. 

Nevertheless, the PurimarTM System applies a neutralization process upon discharge of the 

treated ballast water to ensure environmental acceptability. Neutralizing agents chemically 

reduce any free chlorine and/or hypochlorous acid to chloride ion and any free bromine 

and/or hypobromous acid to bromide ion. Because neuralizing agent is not an Active 

Substance or a Relevant Chemical, it is considered to fall under the Other Chemical 

category. 
MEPC 61/2 

Annex, page 18 

I:\MEPC\61\2.doc 

Sodium thiosulfate is used in the PurimarTM System to neutralize residual oxidants that may 

be present in treated ballast water discharge. Sodium thiosulfate has been used in the pulp 

and paper industry and is currently tried to be used as a neutralizing agent. 

Compared to the single reaction of other neutralizing agents (sodium sulfite, bisulfate or 

metabisulfite), sodium thiosulfate has multiple reactions with chlorine or bromine species. It is 

also an effective means of removal for any combined chlorine or bromine species such as 

chloramines or bromine: 

Sodium sulfite: Na2SO3 + HOCl → Na2SO4 + HCl 

Sodium bisulfite: NaHSO3 + HOCl → NaHSO4 + HCl 

Sodium metabisulfite: Na2S2O5 + 2HOCl + H2O → 2NaHSO4 + 2HCl 

Sodium thiosulfate: Na2S2O3 + 4Cl2 + 5H2O → 2NaCl + 2H2SO4 + 6HCl 

 Na2S2O3 + 4OCl + H2O → 2NaCl + 2SO4 + 2HCl 

 Na2S2O3 + 4HOCl + H2O → 2NaHSO4 + 4HCl 

 2Na2S2O3 + HOCl → Na2S4O6 + NaCl + NaOH 

 Na2S2O3 + 4NH2Cl + 5H2O → 2NaHSO4 + 4NH4Cl 

At the pH of seawater, theoretical dosing rate of sodium thiosulfate to remove one part of 

chlorine (present at mg/L concentrations) will be 1.7 - 1.8 parts by weight. 

TWECO has conducted the lab-scaled test to evaluate the actual dosing rate of sodium 

thiosulfate to neutralize residual TRO in the PurimarTM System. Although the level of TRO 

was decreased in proportion to the amount of sodium thiosulfate, theoretical dosing rate 

of 1.8 parts was not sufficient to neutralize TRO below 0.1 mg/L TRO. Rather, depending on 

water condition and initial TRO level, the required dosing rates to ensure residual TRO level 

below 0.1 mg/L TRO were ranged from 2.57 parts. Based on these results, 3 parts of sodium 

thiosulfate against residual TRO is applied as set point for the neutralizing agent of 

the PurimarTM System. 

During the preliminary and land-based test runs of the PurimarTM System, measurement of 

TRO concentrations in the discharged ballast water after addition of 3 parts of sodium 

thiosulfate has been conducted for different water types at various Active Substance 

treatment and at different holding times. TRO was detected below 0.1 mg/L even at the worst 

expectable condition of immediately after treatment of 3 mg/L TRO Active Substance, in 

which 9 mg/L sodium thiosulfate was added. Actually, in the PurimarTM System, 

a 32% aqueous solution of sodium thiosulfate is loaded aboard from a filling station, stored in 

holding tanks and injected into the ballast line during deballasting operations to neutralize 

any residual TRO. The injected amount of sodium thiosulfate is monitored and controlled to 

apply a small excess (<9 mg/L [3 parts against TRO of 3 mg/L TRO]) to ensure that residual 

TRO level is maintained below 0.1 mg/L TRO in the discharged ballast water. 

The added sodium thiosulfate is approved to chemically reduce any residual oxidants and is 

expected to be in the form of sulfate ion (SO4

2-). Seawater typically contains 

approximately 3 g/L (or 3,000 mg/L) of sulfate ion. Thus, the concentration of sodium 

thiosulfate that might be added to the discharged ballast water is negligible, and the 

generated sulfate ion concentration in the seawater will also be negligible. The reaction might 

produce some acid, which in the highly buffered ballast water will not lower the apparent pH 

of the treated water. Exact value experimenting from land-based test and onboard test will be 

calculated. 
MEPC 61/2 

Annex, page 19 

I:\MEPC\61\2.doc 

3.2 Results of efficacy testing 

3.2.1 Preliminary experiments for the system application 

The preliminary operating experiments for the system application were performed by using 

the TWECO pilot-scale test set-up with the flow rate of 5m3

/hr and the TWECO 

supplementary laboratory-scale apparatus at NLP R&D Centre in Ulsan and MBDC in Busan, 

respectively. 

3.2.1.1 Laboratory-scale efficacy testing 

The laboratory-scale efficacy testing was conducted at MBDC. Varying hypochlorite 

concentrations were applied and TRO levels were measured at different time intervals after 

treatment. Tables 3.2 and 3.3 (see the complete confidential dossier) below presents the 

results of commercial seawater sample containing 1.5 mg/L total organic carbon (TOC). 

Whereas a TRO concentration of 7 mg/L was needed to inactivate zooplankton 

(Artemia salina) at Day 2 after treatment, 3 mg/L TRO was sufficient to inactivate 

phytoplankton (Tetraselmis suecica) immediately after treatment. 

When using chlorine-based water disinfection, it is important to discuss the concept of 

oxidant decay and demand. 

Studies on the decay of TRO produced by the TWECO laboratory-scale electrolytic 

apparatus have been performed, and Figure 3.4 (see the complete confidential dossier) 

provides example of the decay of TRO observed over time for varying concentrations of 

hypochlorite treatment. Regardless of the initial oxidant dose, the residual oxidant 

concentration decay over time. 

Oxidant demand is defined simply as the difference between the amount of oxidant added to 

the water and the amount of oxidant remaining at the end of a specified contact period. 

When an oxidant is added to natural waters, it will react (oxidize) with organisms and other 

components (e.g., natural minerals, organic matter) normally present in natural waters. 

These components, often measured as TOC, determine the oxidant demand of the water. 

As such, for effective treatment, an oxidant needs to be applied at a concentration that 

exceeds the demand of the water source and also maintain a residual concentration within 

the ballast tanks. This allows for sufficient concentration and contact time to ensure complete 

and effective inactivation of HAMP. 

Studies on the demand/decay of TRO produced by the TWECO laboratory-scale electrolytic 

apparatus have been performed, and Figure 3.5 (see the complete confidential dossier) 

provide examples of the TRO demand/decay results of commercial seawater samples added 

with various amounts of glucose. The initial TRO concentration decays quickly immediately 

after treatment, which is proportional to the amount of added glucose, and then more slowly 

after the demand of the water was met. Regardless of water type, decay of TRO follows a 

predictable and consistent pattern. 

Empirical studies over a wide range of water qualities and TOC levels have shown that an 

applied concentration of <10 mg/L of TRO results in effective ballast water treatment. This 

relationship is consistent with the results shown in Figure 3.5. Initial TRO concentration 

of 10 mg/L sustained a sufficient TRO level (>6 mg/L at 3 hours after treatment and >1 mg/L 

at 1 day after treatment) to disinfect the seawater sample containing TOC level up 

to 20 mg/L. 
MEPC 61/2 

Annex, page 20 

I:\MEPC\61\2.doc 

3.2.1.2 Pilot-scale efficacy testing 

The pilot-scale efficacy testing was conducted at NLP R&D Centre in Ulsan. TOC level of the 

source seawater in Ulsan was 1.08 mg/L - 2.77 mg/L. The test set-up is not simply a system 

for laboratory testing, but rather closely resembles a ship's ballast water system regarding 

filtering and neutralizing units. Pre-filtration of the ballast water incorporated as part of the 

test set-up removed bigger zooplankton and showed excellent results in eliminating viable 

organisms present in the water before treatment at a TRO concentration 

of 2 mg/L – 3.5 mg/L. Results of biological efficacy testing are summarized in Tables 3.4 

and 3.5 (see the complete confidential dossier). 

Studies on the decay of TRO also have been performed during the preliminary operating 

experiments for the system application using the TWECO pilot-scale test set-up as shown in 

Figure 3.6. Although all TRO levels in the ballast tanks declined over time especially 

within 24 hours, the pattern of decay is variable depending on water condition. From time to 

time, changes of the water quality parameters, such as biological production rates, TOC, pH, 

and temperatures, may affect both the dissolution and decay rates of an oxidant. 

During the pilot-scale efficacy testing of brackish water sample, tap water was added to the 

source seawater to adjust salinity. All the water quality parameters of the test water will be 

evaluated during the land-based test runs, and only those events fulfilled Guidelines (G8) 

requirements for the water quality will be taken into further considerations for the test cycles. 

In the case of brackish water treatments, amendments will be made to increase the organic 

and suspended solids loads. 

Figure 3.6: TRO decay of TWECO pilot-scale test cycles (P1 – P4) 

3.2.2 Land-based test run for the system confirmation 

The efficacy testing of full PurimarTM system installed on the TWECO test barge was 

conducted at Busan Port (>32 PSU). The test protocol evaluated biological treatment 

performance based on IMO Guidelines (G8), and operational/maintenance tests and 

challenge water tests were accomplished for operation and maintenance, reliability, cost 

factors, environmental acceptability, and safety. 
MEPC 61/2 

Annex, page 21 

I:\MEPC\61\2.doc 

3.2.2.1 Fulfilment of the chemical water quality criteria 

All relevant environmental water parameters are summarized in Table 3.6. 

Table 3.6: Chemical water quality parameter of the land-based test runs for the PurimarTM

System (F-1) (see the complete confidential dossier) 

The test run fulfilled Guidelines (G8) requirements for the chemical water quality criteria for 

land-based test, and thus, have been taken into further considerations for other testing. 

3.2.2.2 Fulfillment of the biological water quality criteria 

Results of measurement of TRO concentration and biological efficacy testing are 

summarized in Tables 3.7 and 3.8, respectively. 

Table 3.7: TRO concentration of the land-based test runs for the PurimarTM System (F-1) 

(see the complete confidential dossier)

Table 3.8: Biological water quality parameter of the land-based test runs for the PurimarTM 

System (F-1) (see the complete confidential dossier) 

The number of living organisms in the untreated and PurimarTM System-treated water 

samples met the D-2 regulation. TRO concentration of 3 mg/L treating ballast seawater 

containing 6.95 mg/L TOC effectively inactivated zooplankton, phytoplankton and bacteria. 

This result indicates that it is sufficient to disinfect HAMP in ballast water with only 

the PurimarTM system operating in situ during ballast water uptake. Thus no other treatment 

mechanism is required to boost the efficacy of the PurimarTM system. 

Water qualities where ballast water uptake may occur can impact the oxidant demand as it 

can vary by location and season. This in turn can affect the concentration of biocide solution 

needed to adequately inactivate HAMP. Therefore, the effective concentration generated by 

the PurimarTM System to meet the oxidant demand of the incoming ballast water while also 

maintaining a residual concentration is adjusted based on the water quality. 

In this sense, the PurimarTM System is designed to control the amount of Active Substances 

produced to effectively treat HAMP, yet avoid over-production of the biocide to control the 

level of potential DBPs. This is accomplished using TRO sensor (CLX), which allows for a 

direct on-site measurement of TRO level. As TRO sensor (CLX) needs a time gap of 7.5 min 

for an initial reading of TRO level, ORP sensor (Jumo) is additionally adopted for an in-line 

rapid determination of the amount of oxidation reduction potential (ORP) of the water. The 

amounts of TRO and ORP are measured in mg Cl2/L and millivolts (mV), respectively. When 

biocide solution is added to water, the TRO and ORP readings increase with an increase in 

the concentration of biocide solution. Similarly, when a neutralizing agent such as sodium 

thiosulfate is added to the water, the TRO and ORP readings will drop to a low level. In this 

way, TRO and ORP measurements provide a practical and efficient method of controlling 

biocide concentration and ensure optimized water disinfection. More discussions on how the 

PurimarTM System incorporates TRO and ORP technology is presented in appendix 7. 

In 2010, further land-based efficacy testing of the PurimarTM System will be conducted 

according to IMO Guidelines (G8) at two different sites with significant difference in water 

qualities – seawater test in Busan Port (>32 PSU) and brackish water test in Nakdong River 

or similar estuary (3~32 PSU). Shipboard testing of a commercial PurimarTM System will also 

be executed in 2010. 
MEPC 61/2 

Annex, page 22 

I:\MEPC\61\2.doc 

3.3 Results of chemical analysis (Relevant Chemicals) 

During the system testing using the TWECO pilot-scale test set-up and the full-scale 

PurimarTM system, measurements of the concentrations of Relevant Chemicals were 

performed by SGS. A water sample was taken from each sampling point, poured into 

pre-labelled sample containers, which included the required preservative for each parameter, 

and transported to the laboratory of SGS. 

The results are summarized in Tables 3.9, 3.10, 3.11, 3.12, and 3.13 (detailed in the 

complete confidential dossier), and the individual test reports including raw data sheets are 

contained in appendix 5. Data were obtained from the water samples collected immediately 

after treatment (Day 0), two days after treatment (Day 2) and five days after treatment 

(Day 5). The samples collected on Day 2n and Day 5n were analysed after neutralization 

with sodium thiosulfate. 

The results, as presented in the above-mentioned tables, indicate that bromate was always 

below the MDL in all samples. Considering the relatively high MDL of SGS, the same water 

samples were requested to Korea Testing and Research Institute (KTR) for the measurement 

of bromate. Even the finding of MDL of KTR was as low as 0.1 μg/L, bromate was not 

detected in all water samples (appendix 5). 

From the other tested compounds, two THMs (tribromomethane and 

chloro-dibromomethane), all nine HAAs (monochloroacetic acid, dichloroacetic acid, 

trichloroacetic acid, monobromoacetic acid, dibromoacetic acid, tribromoacetic acid, 

bromochloroacetic acid, bromodichloroacetic acid and dibromochloroacetic acid), and two 

HANs (dichloroacetonitrile and dibromoacetonitrile) were detected. 

The maximum concentrations of total THM, HAA, and HAN, which have been detected in 

treated ballast water during the development of PurimarTM System, were 0.394 mg/L 

(test cycle P-4(1) on Day 5, Table 3.11), 0.109 mg/L (test cycle P-3 on Day 5, Table 3.10), 

and 0.0517 mg/L (test cycle P-4(1) on Day 2 following neutralization, Table 3.11), 

respectively. The detected highest concentration of each Relevant Chemical is summarized 

in Table 3.14 (see the complete confidential dossier). 

The data show high levels of brominated by-products, particularly tribromomethane, in 

treated water. In oxidation reactions with hypobromous acid, the bromide ion is formed; so, in 

excess of chlorine, this ion is rapidly reconverted to hypobromous acid. Thus, while chlorine 

is consumed, the bromine concentration remains constant upon oxidation reactions. 

Consequently, the loss of bromine may be mainly attributed to substitution reactions as long 

as chlorine is present in the water. For that reason, the production of brominated by-products 

upon chlorination is greatly enhanced with increased bromide concentrations in the water 

samples; on the contrary, increasing the free available chlorine results in a reduction in 

bromine incorporation. 

For the brackish water test run, there is an additional factor likely contributing to the levels of 

brominated organic by-products observed. To reach the desired brackish water salinity, 

natural seawater was diluted with tap water from a municipal water source (such as test 

cycle P-3). This water had been previously chlorinated using chlorine gas. The researchers 

aerated the water to remove pre-existing chlorine; however, at the pH level of the test water 

most of the residual chlorine presented in the tap water would exist as HOCl/OCl-

 and some 

HOBr/OBr-

 if the chlorine had a small bromine impurity. Therefore, use of local chlorinated 

tap water may potentially affect the level of hypochlorite ion in treated water and may also be 

a source of bromine. 
MEPC 61/2 

Annex, page 23 

I:\MEPC\61\2.doc 

Further analysis of DBPs will be conducted during land-based test runs for the land-based 

testing of the PurimarTM System in 2010. In the case of the brackish and fresh water test 

runs, amendments will be made to increase the organic matter and suspended solids loads. 

Their addition to test waters appears to have unintentionally changed the production of 

DBPs. Therefore, due to the addition of amendments, the potential presence of bromine 

present in the chlorine source prior to treatment, along with the presence of pre-existing 

disinfection by-products, it can be reasonably deduced that these factors influence the levels 

of brominated by-products in the fresh water and brackish water studies. 

3.4 Data on effects on aquatic plants, invertebrates and fish, and other Biota, 

including sensitive and representative organisms 

WET testing of water treated with the PurimarTM System has been conducted by MBDC. 

All WET data disclosed were obtained at the preliminary and land-based test runs that meet 

ballast water performance standards concerning biological efficiency. For every Active 

Substance and Relevant Chemical, data are presented and discussed either on the basis of 

toxicological tests (whole effluent water) or existing toxicological knowledge for separate 

Active Substances and Relevant Chemicals. 

3.4.1 Whole Effluent Toxicity (WET) test for the evaluation of acute and chronic 

aquatic toxicity 

All WET tests followed short-term methods deemed qualitatively equivalent to OECD and 

ASTM for estimating acute and chronic aquatic toxicity. Samples were collected from 

challenge tests in which organism and organic-enriched ballast water was treated with 

hypochlorite to a TRO concentration to disinfect sufficiently. These tests were done in 

conjunction with evaluation of efficacy and DBPs. 

MBDC evaluated treated water collected at differing time intervals after treatment and after 

neutralization with sodium thiosulfate using algae, invertebrates, and fish in saltwater. Water 

samples were collected immediately after treatment with hypochlorite (Day 0), two days after 

hypochlorite treatment, and five days after hypochlorite treatment. These samples were 

collected and tested prior to the neutralization step (i.e. pre-neutralization). For toxicity 

testing post-neutralization, samples were collected from challenge tests in which hypochlorite 

treated water was held for two days or five days and then neutralized with an excess 

concentration of sodium thiosulfate. 

Immediately after verification of field water samples, the water samples were passed through 

the filtering system (pore size 0.45 μm) and measured the TRO, pH, temperature, salinity, 

and dissolved oxygen (DO). Test substances prepared from the treated water samples were 

subjected to the concentration-response tests – control dilution water (0%) and a minimum of 

three concentrations commonly selected to approximate a geometric series, i.e. 100%, 75%, 

50%, 25% and 12.5%. With respect to the formulation of the dosing preparation, commercial 

natural seawater was used as a diluent. As the test substances prepared from the untreated 

ballast water samples are likely to be non-toxic, the single concentration (undiluted, 100% 

solution) was subjected to the limit test. 

All WET tests were initiated simultaneously within 6 hours of sampling. For chronic toxicity 

test with larval fish, single treated water samples stored in locked refrigerator (stored sample) 

or daily treated water samples (fresh sample) were used for the renewal of test substances. 
MEPC 61/2 

Annex, page 24 

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3.4.1.1 Water quality parameters in WET test substances 

All the water quality parameters satisfied the criteria for the validity of WET test. The results 

are summarized in Table 3.15. (See the complete confidential dossier.) 

3.4.1.2 TRO in WET test substances 

As soon as the test substances for WET tests were prepared and diluted, the concentration 

of Active Substance was measured shortly prior to the beginning of the WET test. Results 

are summarized in Table 3.16 (see the complete confidential dossier). The TRO level after 

filtration was dramatically reduced comparing to that on delivery (at laboratory TRO 

concentration in Tables 3.4 and 3.7). This result suggests that chlorination-produced 

oxidants may dissipate very quickly from samples that are exposed to sunlight and 

atmosphere and bubbled with ambient air. Therefore, investigators should consider the 

implications of the loss of oxidants during sampling process and test substance preparation 

for WET testing in estimating overall or residual toxicity of Active Substance in chlorinated 

seawater. In this sense, TWECO has opted to include a TRO neutralizer as standard in the 

PurimarTM System design to address any possibility of residual TRO of concern in the 

treated ballast water discharge. 

Results of WET tests 

The WET test results are presented in the following sections, and the individual test reports 

including raw data sheets are contained in appendix 4. 

Growth inhibition test with marine algae 

Ninety-six hour growth inhibition test with marine algae, Phaeodactylum tricornutum and 

Dunaliella tertiolecta was performed on the PurimarTM System. Table 3.17 summarizes the 

results. (See the complete confidential dossier.) 

Acute toxicity (survival) test with invertebrates 

Twenty-four hour survival test with marine invertebrates, Brachionus plicatilis was performed 

on the PurimarTM System. Table 3.18 summarizes the results. (See the complete confidential 

dossier.) 

Acute toxicity (survival) test with larval fish 

Sheepshead minnow, Cyprinodon variegatus, larvae (preferably less than 24 hours old) 

exposed in a static non-renewal system for 96 hrs was performed on the PurimarTM System. 

Table 3.19 summarizes the results (see the complete confidential dossier). 

Chronic toxicity (reproduction or population growth) test with invertebrates 

Four-day reproduction (population growth) test with marine rotifer, Brachionus plicatilis was 

performed on the PurimarTM System. Table 3.20 summarizes the results. (See the complete 

confidential dossier.) 

Chronic toxicity (growth) test with larval fish 

Sheepshead minnow, Cyprinodon variegatus, larvae (preferably less than 24 hours old) 

exposed in a static renewal system for 7 days was performed on the PurimarTM System. 

Table 3.21 summarizes the results. (See the complete confidential dossier.) 
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As would be expected, the untreated samples (C0, C2, and C5) exhibited no minimal toxicity 

in any of the tests. The median lethal concentrations (LC50) were greater than 100% solution, 

meaning that the untreated seawater showed no toxicity. 

For the treated samples, in summary, all test substances prepared from water samples 

immediately after treatment (T0) and most test substances prepared from water samples 

two days after treatment (T2) showed residual toxicity. Although the results of WET tests 

indicate that the latent toxicity is not expected in the discharged ballast water after five days 

storage (T5), data of TRO concentrations at field from the same test run cycles of 

the PurimarTM System (see Table 3.4 and 3.7) suggest that some chlorination-produced 

oxidants responsible for marine organism mortality may persist at toxic concentrations in the 

ballast waters two to five days following treatment depending on storage conditions and 

exposure to sunlight. 

Risk-based decisions need to be made to set maximum acceptable discharge concentrations 

and conditions (potentially taking into account discharge rates and dilution or degradation 

following discharge into receiving waters). As has been applied for other electrolysis-based 

Ballast Water Management Systems that has been granted IMO Approval by MEPC, it is 

therefore, the TRO of 0.1 mg/L that is considered in this application. Chemical treatments, 

such as with sodium thiosulfate, may provide a fast and effective means of reducing residual 

TRO concentrations without the risk of endangering organisms in the vicinity of the vessel 

undergoing chlorination. 

Actually, no residual toxicity was observed for all test species in the sodium 

thiosulfate-treated (post-neutralized) water samples of Day 2 (T2n) and Day 5 (T5n) 

regardless of pre-neutralized TRO concentrations. Furthermore, MBDC additionally 

performed repeated-dosing chronic toxicity test with larval fish using post-neutralized water 

samples for the daily renewal of test substances. Water samples were prepared by diluting 

the biocide solution generated from the TWECO laboratory-scale electrolytic apparatus with 

commercial seawater to a 1 mg/L of TRO, and then neutralizing with a 2.36 mg/L of sodium 

thiosulfate. Seven repeated dosing of freshly prepared water samples showed no toxicity 

(see Table 3.21), which suggests that sodium thiosulate up to 16.52 mg/L would not be 

expected to exhibit an adverse effect against aquatic organisms. 

In conclusion, evaluating toxicity to aquatic organisms at various holding times after 

treatment (without neutralization) demonstrates that the residual chlorine remains effective 

after treatment. Additionally, performing toxicity testing with post-neutralization verifies that 

the sodium thiosulfate treatment is effectively removing residual oxidants, making treated 

water discharge environmentally safe and that the neutralizing agent is not itself toxic. 

3.4.2 Acute and chronic aquatic toxicity of active substance, other chemical and 

relevant chemicals 

A literature search was conducted to locate existing aquatic toxicity data for the substances 

associated with the PurimarTM System. The data summarized in Tables 3.22 and 3.23. 

(See the complete confidential dossier.) 

3.4.3 Endocrine disruption 

Endocrine disrupting chemicals (EDCs) is a compound, either natural or synthetic, which 

environmental or inappropriate development exposures alters the hormonal and homeostatic 

systems that enable the organism to communicate with and respond to its environment. 
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There are no indications, e.g., from the structure of the substance or results of other 

available studies that any of Active Substance (TRO; HOCl/HOBr) or Relevant Chemicals 

causes endocrine disruption. Active Substances and Relevant Chemicals that were 

mentioned above were not found in any literature. 

3.4.4 Sediment toxicity 

The sediment toxicity of a chemical is a function of the ability of the chemical to be adsorbed 

to sediment as well as its persistence and toxicity. The organic carbon partition coefficient 

(Koc) is the chemical adsorption coefficient normalized to the organic carbon content of soil 

or sediment. This parameter can provide insight as to whether a material will cling to soils or 

sediments in water and whether they will desorb or be tightly bound. The octanol/water 

partition coefficient (Kow) is defined as the ratio of a chemical’s concentration in the octanol 

phase to its concentration in the aqueous phase of a two-phase octanol/water system. 

Measured values of Log Kow for organic chemicals range from -4.53 to 2.4. Generally, 

chemicals with low Log Kow values can be considered relatively hydrophilic (i.e. tendency for 

high water solubility, low potential for sediment adsorption), while chemicals with high 

Log Kow values are considered hydrophobic (i.e. low water solubility, high potential for 

sediment adsorption). 

Active Substances and Relevant Chemicals have been assessed for persistence in natural 

waters and concerning accumulation potential in sediments. The literature reported and/or 

estimated log Kows and Kocs are shown for the Active Substances and Relevant Chemicals 

in Table 3.24 (see the complete confidential dossier). 

The TRO Active Substances are all inorganic substances and therefore have a very low 

calculated Koc. None of the organic Relevant Chemicals appear to have the potential to be 

absorbed to sediments to a significant extent based on their low Kocs (<500 L/kg) and other 

information in the literature (HSDB/TOXNET). With the exception of the THMs, all of the 

Active Substances and Relevant Chemicals have very low log Kow’s, which indicates the 

compounds are hydrophilic. The THMs, as would be expected, are moderately hydrophobic. 

However, none of the log Kow values located in the literature and/or estimated is ≥ 3. 

Thus, the low Kocs and log Kow values for all of the Active Substances and Relevant 

Chemicals indicate that the chemicals would not readily partition and accumulate to sediment 

and therefore, be of concern to benthic organisms residing in the sediment. (See the 

complete confidential dossier.) 

3.4.5 Bioavailability/biomagnification/bioconcentration 

The bioconcentration factor (BCF) is the concentration of a particular chemical in/on fish or 

specified tissues thereof divided by the concentration of the chemical in the surrounding 

medium at steady state. The bioconcentration factors (BCFs) are used to relate pollutant 

residues in aquatic organisms to the pollutant concentration in ambient waters 

(reported as L/kg). This physical property is used as the indicator of a chemical potential to 

bioaccumulate and especially characterizes the accumulation of pollutants through chemical 

partitioning from the aqueous phase into an organic phase, such as fish or other aquatic 

organism tissues. The BCF is the best measure of bioavailability, biomagnification, and 

bioconcentration. Generally, a high potential BCF is greater than 1000, a moderate 

potential BCF is less than a 1000 but greater than 250, and a low potential BCF is less 

than 250. When the BCF of specific chemical is more than 1000, the chemical is considered 

bioaccumulative. The BCFs summarized in Table 3.24 are all much lower indicating a low
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potential for significant bioconcentration/bioaccumulation in aquatic organisms 

(HSDB/TOXNET). Little biomagnification should occur in the food web since the chemicals 

are not readily bioconcentrated or bioaccumulated. 

3.4.6 Food web/population effects 

In case of that properties of the substances have the tendency of bioaccumulation and/or 

persistence in the environment, food web and population effects will occur. 

Little biomagnification and persistence in aquatic and mammalian food webs is anticipated 

from the Active Substances or Relevant Chemicals. This conclusion is based on the results 

from aquatic toxicity testing, low PEC values, mammalian toxicity evaluation and low Kocs 

and BCFs of the Active Substances and Relevant Chemicals. 

3.5 Data on mammalian toxicity 

Mammalian toxicity studies have not been performed separately for Active Substances or 

Relevant Chemicals formed during or after application of the PurimarTM System. Testing with 

vertebrate animals should be avoided if other types of information are available that allow an 

assessment of hazards and risks to humans. 

Tables 3.25 to 3.30 (see the complete confidential dossier) show data on mammalian toxicity 

for different endpoints and effects. The data in tables are referred from the government 

reports such as WHO, IPCS and USEPA and so on. Some data was also referred from 

Material Safety Data Sheets (MSDS). 

Potential for human exposure to the substances associated with the PurimarTM System is 

discussed in detail in appendix 8. 

3.6 Data on environmental fate and effect under aerobic and anaerobic condition 

3.6.1 Modes of degradation (Biotic; Abiotic) 

The Active Substances (hypochlorous acid and hypobromous acid) decay in seconds to hour 

as shown in key data summary (appendix 1); This shows how to produce an oxidizing 

environment and Active Substances action mechanism. DBPs are generated with the 

presence of organic matter by the action mechanism of the Active Substances. 

The generated DBPs are described in section 3.1.3 and the degradation data of biotic and 

abiotic of DBPs are shown in key data summary (appendix 1). The degradation of biotic for 

all of these simple halogenated organic compounds is on the order of days to weeks. 

The degradation of abiotic of these compounds is longer than biotic. 

3.6.2 Bioaccumulation, partition coefficient, octanol/water partition coefficient 

The bioconcentration factor (BCF) is the concentration of a particular chemical in/on fish or 

specified tissues thereof divided by the concentration of the chemical in the surrounding 

medium at steady state. The bioconcentration factor (BCF) is used to relate pollutant 

residues in aquatic organisms to the pollutant concentration in ambient waters 

(reported as L/kg). This physical property characterizes the accumulation of pollutants 

through chemical partitioning from the aqueous phase into an organic phase, such as the gill 

of a fish. Generally, a high potential BCF is greater than 1000, a moderate potential BCF is 

less than a 1000 but greater than 250, and a low potential BCF is less than 250. 

The literature reported and/or estimated BCFs are shown for the Active Substances and 

Relevant Chemicals in Table 3.24 (see the complete confidential dossier). 
MEPC 61/2 

Annex, page 28 

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The organic carbon partition coefficient (Koc) is the ratio of the mass of chemical that is 

adsorbed in the soil per unit mass of organic carbon in the soil or sediment per equilibrium 

chemical concentration in solution. Koc values are useful in predicting the mobility of organic 

contaminants in soil or sediment; high Koc values correlate to less mobile organic chemicals 

while lower Koc values correlate to more mobile organic chemicals. The octanol/water 

partition coefficient (Kow) is defined as the ratio of a chemical’s concentration in the octanol 

phase to its concentration in the aqueous phase of a two-phase octanol/water system. 

Measured values of log Kow for organic chemicals range from -4.53 to 2.4. Generally, 

chemicals with low Log Kow values can be considered relatively hydrophilic (i.e. tendency for 

high water solubility, low potential for sediment adsorption), while chemicals with 

high Log Kow values are considered hydrophobic (i.e. low water solubility, high potential for 

sediment adsorption). The literature reported and/or estimated Log Kows are shown for 

the Active Substances and Relevant Chemicals in Table 3.24. 

Based on the BCFs data shown in Table 3.24 for both Active Substances and Relevant 

Chemicals all of these substances have less than 250 of BCFs, indicating that there is no 

bioaccumulation in aquatic organisms or present a significant food chain risk. With the 

exception of the THMs, all of the Active Substances and Relevant Chemicals have very low 

log Kow’s, which indicates the compounds are hydrophilic. The THMs, as would be 

expected, are moderately hydrophobic. However, none of the log Kow values located in the 

literature and/or estimated is ≥ 3. The log Kow and BCF are related to each other with the 

BCF being the more relevant parameter to determine the likelihood of impacts of a chemical 

to aquatic organisms. The Kocs for all chemicals in Table 3.24 show that all of chemicals are 

expected to have high mobility and if released water, all of chemicals are not expected to 

absorb to suspended solids and sediment in water. 

3.6.3 Persistence and identification of the main metabolites in the relevant media 

Higher tier simulation tests not required; this section is not applicable. 

3.6.4 Reaction with organic matter 

The formation of DBPs in electrolysis system which generates chlorine is well known. 

Bromated and four major classes of DBPs such as THMs, HAAs, HANs, and HPhs have 

been measured in treated ballast water with the PurimarTM System. 

DBP formation is a result of disinfectant reactions with natural organic matter, often 

measured as TOC, which serves as the organic precursor, and/or bromide ion, which serves 

as the inorganic precursor. Reactions between disinfectant halogens (e.g., chlorine and 

bromine) and DBP precursors include substitution reactions and carbon bond oxidation 

reactions. Water quality (e.g., pH, temperature, bromide level, TOC) and treatment 

conditions (e.g., hypochlorite dose, contact time, removal of organic matter prior to 

treatment) influences the formation of DBPs. 

Analysis for DBP concentrations has been conducted during system testing of the PurimarTM

System. Different water types (brackish and seawater) were treated and then evaluated for 

DBPs. The data are presented in section 3.3 "Result of chemical analysis (Relevant 

Chemicals)". Additional analysis of DBP concentrations in treated ballast water will be 

performed during land-based testing for Final Approval and the results will be reported in the 

Final Approval dossier. 
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I:\MEPC\61\2.doc 

3.6.5 Potential physical effects on wildlife and benthic habitats 

As shown in Tables 3.31 and 3.32, the chemical and physical properties of the Active 

Substances and Relevant Chemicals generated from the PurimarTM System do not have 

physical effects on wildlife and benthic habitats. 

3.6.6 Potential residues in seafood 

Chemicals detected in treated ballast water that is discharged may affect seafood consumers 

only if they tend to bioaccumulate (within a trophic level, an increase in concentration of a 

substance in tissues due to uptake from food and sediments) or biomagnify (an increase in 

the concentration of a substance in the food web) in seafood. 

The bioaccumulation criteria per the Methodology for information gathering and the conduct 

of work of the GESAMP-BWWG (MEPC 58/2/7, annex 4) include an octanol-water partition 

coefficient (Log Kow) of ≥3 or a bioconcentration factor (BCF) >2000. The chemicals 

identified in this risk assessment all have Log Kows less than 3 and BCFs less than 2000, 

and are therefore not expected to persist in the food web. 

3.6.7 Any known interactive effects 

No other interactive effects are known. 

3.7 Physical and chemical properties 

The physical and chemical properties for the Active Substances, Relevant Chemicals and 

Other Chemical are briefly shown in Table 3.31 (see the detailed data in the confidential 

dossier and appendix 1 "Key data"). 

3.8 Analytical methods at environmentally-relevant concentrations 

Please refer to section 2.5 "Test methods". Full details are contained in appendix 3 "QAPP" 

(see the complete confidential dossier). 

4 USE OF THE ACTIVE SUBSTANCE OR THE RELEVANT CHEMICAL 

The PurimarTM System is designed to require minimal input from the ship's crew, with the 

system starting and stopping the necessary treatment steps based on electronic signals. 

This minimizes added duties to ship’s crew and ensures proper ballast water treatment. 

Please refer to section 4 "General description of the PurimarTM System" (see the complete 

confidential dossier), section 3.1 "Identification of Preparation, Active Substance and 

Relevant Chemical", and section 3.2 "Results of efficacy testing". Full details of operation 

for PurimarTM System are contained in appendix 7 "PurimarTM BWMS Manual" 

(see the complete confidential dossier). 

5 MATERIAL SAFETY DATA SHEETS 

In this section, the hazard classifications are presented for reflecting report hazards only, but 

actual potential hazards related to the PurimarTM System are not considered. The PurimarTM

System will mitigate the potential hazards with the proper safety mechanisms and practices. 

Hazard classification of Active Substance, Other Chemical and Relevant Chemicals 

described below is based on MSDS of commercially available products that contain 

referenced chemicals at significantly greater concentrations that were produced by the 

PurimarTM System or could be found in the treated ballast water. 
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Annex, page 30 

I:\MEPC\61\2.doc 

Material Data Safety Sheet (MSDS) and/or International Chemical Safety Card (ICSC) 

information is provided in appendix 6 (see the complete confidential dossier). 

5.1 Hazard classification of Active Substance 

Hypochlorous acid to be known as bleach will be generated at a concentration of 1,000 mg/L 

before injected into the ballast water. But after injected, the concentration will be 

approximately 10 mg/L in the ballast water. 

MSDS is not available for the chemical composition to be generated inside the PurimarTM 

System. ICSC #0482 (<10% solution) has been used for hazard classification instead of 

MSDS: 

- R-Phrases: R31, R36/38 / S-Phrases: S1/2, S28, S45, S50, S61 

Normally, sodium hypochlorite is generated and used during the PurimarTM System is only 

running and after stopping the system; it is not stored on board. The only storage of sodium 

hypochlorite on board the vessel is in the ballast tanks at a concentration of < 10 mg/L. 

5.2 Hazard classification of Relevant Chemicals 

5.2.1 DBPs 

THMs, HAAs, HANs, HPhs and bromate disinfection by-products (DBPs) may be generated 

at varying low-level concentrations in ballast water during the PurimarTM treatment process. 

Concentrated solutions of these substances will never be transported or utilized on board 

ship and exposed to human. As such, typical MSDSs for these low-level substances (parts 

per billion range) do not accurately represent the potential hazards that may be presented by 

these chemicals in treated ballast water. Determining the hazards for these substances at 

part per billion levels is not feasible when the MSDSs reflect hazards for much higher 

concentrations. As such, the R-phrases and S-phrases are not detailed for these disinfection 

by-products; however, the MSDSs are included in appendix 6 (see the complete confidential 

dossier). 

5.2.2 Hydrogen gas

During electrochemical process, the PurimarTM System generates hydrogen gas as a 

by-product. As discussed in section 3.1.3, hydrogen is separated immediately upon exit from 

the electrolytic cell using a cyclone separation device and is not allowed to enter the ballast 

water piping. Hydrogen gas transmitted to the de-gas tank is diluted with the air supplied by 

air blower. The concentration of diluted hydrogen gas is less than 1% (well below the 4% 

Lower Explosive Limit) before reaching the air. Furthermore, non-compressed hydrogen is 

not considered a hazardous material; however, hazard classifications according to 

ICSC #0001 are as follows: 

- R-Phrases: R12 / S-Phrases: S2, S9, S16, S33 / F+ symbol 

5.3 Hazard classification of Other Chemical 

Sodium thiosulfate 32% solution is added to hypochlorite treated ballast water as it is being 

discharged from the ship. This is the only substance stored on board. The quantity stored will 

vary depending on the amount of ballast water treated and will be specific to each
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installation. Sodium thiosulfate is stored in vented SST(stainless steel) or PE(polyethylene) 

or FRP(fibre reinforced plastic) tanks. Hazards according to the MSDS are as follows: 

- R-Phrases: R20, R22, R36, R37, R38 / S-Phrases: S26, S36 

6 RISK CHARACTERIZATION 

6.1 Screening for Persistence, Bioaccumulation and Toxicity 

Persistence 

According to the data from mode of degradation (biotic/abiotic) and an evaluation of the 

environmental persistence data for Active Substances, Relevant Chemicals, and Other 

Chemical, there was no significant residual which met the criteria of PBT (Persistence 

Half-life > 60 days in marine water, or > 40 days in fresh water, or > 180 days in marine 

sediment, or > 120 days in fresh water sediment). 

Bioaccumulation 

Using the PBT criteria of either BCF > 2000 or Log Kow ≥ 3, the data for Active substances, 

Relevant Chemicals, and Other Chemical show that the substances have low potential for 

bioaccumulation. 

Toxicity tests 

According to the data on effects on aquatic plants, invertebrates and fish, and other biota, 

including sensitive and representative organisms, there was no significant residual, which 

met the criteria of PBT (Chronic NOEC < 0.01 mg/L). As the chronic aquatic toxicity data was 

not located for all substances, the lowest acute toxicity data points available were 

considered. 

6.2 Evaluation of the treated ballast water 

The PurimarTM System uses chlorination in the ballast water treatment process. Because of 

the concern that toxic materials could be introduced into ballast waters as a result of 

chlorination, numerous studies have been conducted on the PurimarTM System to evaluate 

many aspects of treated water. In addition to the aquatic toxicity data, data on TRO, water 

quality parameters and DBPs have been measured and recorded. 

It is conclusive to say that the latent toxicity is not expected in the final discharged ballast 

water of PurimarTM System in more than two days of storage. Please refer to section 3 of Part 

B "Datasets required in the application (the confidential dossier)". 

Determination of holding time 

The PurimarTM System has the neutralization unit using sodium thiosulfate and this unit will 

be operated to neutralize all residual oxidants at discharge. And also the concentration to be 

used will be properly controlled through using CLX and ORP sensor. So there is no specified 

holding time for the treated water to discharge safely to the environment. 

For the treated water before discharging and the treated water to be mixed neutralizing 

agent, sodium thiosulfate, at discharging, aquatic toxicity testing is performed. In the result, 

there is no adverse effect. And also the result of the repeated dosing toxicity testing using 

excessive treatment of neutralizing agent shows that there is no adverse effect. 
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Therefore, the holding time that treated ballast water needs to be retained is determined by 

the amount of contact time required to properly disinfect and inactivate HAPM. Efficacy 

testing determined that, at low TOC concentrations, a TRO concentration of 7 mg/L was 

needed to inactivate zooplankton (Artemia salina) at Day 2 after treatment, and 3 mg/L TRO 

was sufficient to inactivate phytoplankton (Tetraselmis suecica) immediately after treatment. 

Actually the pilot and full-scale efficacy testing showed that pre-filtration of the ballast water 

incorporated as part of the PurimarTM System removed bigger zooplankton, and TRO 

concentration of 3 mg/L was sufficient to inactivate HAMP present in the water before 

treatment. Furthermore, at high TOC concentrations, initial TRO concentration of 10 mg/L 

sustained a sufficient TRO level (>6 mg/L at 3 hours after treatment and >1 mg/L at 1day 

after treatment) to disinfect the seawater sample containing TOC level up to 20 mg/L. 

Empirical studies over a wide range of water qualities and TOC levels have shown that an 

applied concentration of <10 mg/L of TRO results in effective ballast water treatment. 

Consequently, the PurimarTM System treats ballast water and even though the treated water 

is discharged after short time storage, the number of live organisms is very limited. And also 

there is no aquatic toxicity due to using the neutralization unit. 

6.3 Risk characterization and analysis 

6.3.1 Reaction with organic matter 

As discussed in section 5.3.1, DBPs are generated in disinfection system using chlorine and 

DBPs concentration normally depends on the Active Substance dose and the parameter of 

the treated water such as temperature, pH, TOC. Specially, TOC among the parameter of 

the water affects the concentration of DBPs. So, DBPs will be generated small quantity in low 

TOC level. The PurimarTM System has the filter unit and this unit will pre-treat the ballast 

water. Therefore, the filter unit will reduce an amount of TOC and also reduce the amount of 

the generated DBPs during disinfection. 

In section 3.3, the levels of DBPs of the treated ballast water are shown at various doses of 

Active Substance in different water types and water quality condition. 

The concentrations of DBPs in treated water discharge will be monitored further during 

land-based testing. Results of this testing will be reported in the future dossier for Final 

Approval. 

6.3.2 Characterization of degradation route and rate 

For all substances related to the use of the PurimarTM System, both the biotic and abiotic 

degradation data are shown in key data summary (appendix 1). For DBPs, biotic degradation 

for all of these simple halogenated organic compounds is on the order of days to weeks. 

Abiotic degradation of these compounds is longer. In the case of sodium thiosulfate, 

no specific degradation information was located in the existing literatures. However, for these 

inorganic substances, the BCF, Koc, and Log Kow values indicate low potential for 

bioaccumulation, low adsorption to sediment, and high water solubility. 

6.3.3 Prediction of discharge and environmental concentrations 

Due to the oxidant neutralization step during ballast water discharge, the TRO in treated 

water discharge of the PurimarTM System will be below 0.1 mg/L which is risk-based 

maximum acceptable discharge concentration. Sodium thiosulfate added to ballast water 

discharge is reduced to sulfate ion in the marine environment, and sulfate ion is ubiquitous 

and does not pose unacceptable environmental risks. And it is important to note that acute 
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and chronic toxicity testing of the neutralized whole effluent from the PurimarTM System was 

not toxic to aquatic organisms, regardless of the Relevant Chemical discharge 

concentrations which were detected during the system testing. Therefore Prediction of 

discharge and Environmental Concentrations (PEC) may not be relevant. 

Nonetheless, TWECO derived meaningful PEC values for Active Substances, Other 

Chemicals, and detected stable Relevant Chemicals, reflecting actual environmental 

concentrations when treated ballast water was released in a harbour where dilution and 

mixing would occur. A suitable environmental emission scenario was developed by using 

the MAMPEC model. 

Busan port was chosen because of the detailed statistics available via: 

 - Shipping & Port-Internet Data Centre (SP-IDC) 

 http://www.spidc.go.kr/jsp/index.jsp; 

- Busan Port Authority (BPA) 

http://www.busanpa.com; 

- National Fisheries Research & Development Institute (NFRDI) 

http://www.nfrdi.re.kr; and 

- Marine Charts. 

Environment definition for MAMPEC Model 

As the Busan port is directly connected with an open sea, Default Marina type was used as 

prototype for the MAMPEC model. The land area included in the simulation was excluded 

from total volume. Environment definition using these data is summarized in Table 6.1 (see 

the complete confidential dossier). 

Compound definition for MAMPEC Model 

Parameters for compound definition derived from dataset of Active Substance, Other 

Chemical, and Relevant Chemicals are summarized in Table 6.2. (See the complete 

confidential dossier). 

Emission definition for MAMPEC Model 

The estimated amount of discharged ballast water and the resulting emission definition are 

provided in Tables 6.3 and 6.4, respectively (see the complete confidential dossier). Given 

that the discharged ballast water is generally applied to 30% of G/T (Case 1) and throughout 

(Case 2), the average total release of ballast water is 280,794 m3

/day and 93,399 m3/day, 

respectively. This is believed to be a conservative estimate as it is unlikely that all ships will 

have ballast water that is treated with the PurimarTM System, and not all the ships will 

discharge ballast water. Rather the opposite is the case as ships unloading cargo will take on 

ballast water to compensate for the cargo taken on board. 

Results of MAMPEC Model 

PECs of Active Substance, Other Chemical, and Relevant Chemicals calculated from 

MAMPEC are summarized in Tables 6.5 and 6.6 (see the complete confidential dossier). 
MEPC 61/2 

Annex, page 34 

I:\MEPC\61\2.doc 

6.3.4 Assessment of potential for bioaccumulation 

Seafood such as shellfish and fish can be harvested from areas where treated ballast water 

is discharged. According to the data from bioaccumulation, partition coefficient, and 

octanol/water partition coefficient, there was no significant residuals which met the criteria of 

PBT (Bioaccumulation BCF > 2,000 or LogPoctanol/water [log Kow] ≥ 3). 

As the BCF and log Kow values of the Active Substance, Other Chemical, and Relevant 

Chemicals in the discharged effluent of the PurimarTM System are very low, secondary 

poisoning through the food chain is unlikely to occur, and these compounds will not be found 

in seafood. As a result, the potential for bioaccumulation is not considered necessary to be 

assessed in marine or freshwater organisms, and there is no health risk connected to 

consumption of seafood taken from areas where ballast water is discharged. 

In addition, an assessment of effects to sediment species is not considered necessary to be 

conducted since all the chemicals of concern to partition into the sediment is low 

(e.g., Koc < 500 L/kg). 

6.3.5 Effects assessment 

Chlorination-related toxicity tests have been conducted for several marine taxa, including 

primary producers (microalgae), consumers (zooplankton or amphipod) and predators (fish). 

Unfortunately, the wide range of exposure conditions and test endpoints used among all of 

the marine toxicity tests makes it difficult to quantify a general effect concentration for 

chlorination. Furthermore, analytical measurements taken in most tests were not specific to 

chlorination. As described in section 3.1, the most Active Substance toxic against marine 

organisms exposed to chlorination is oxidants. Chlorination-related toxicity is thus most 

correctly expressed as a function of chlorination-produced oxidants, rather than chlorination 

per se. 

The study to determine the ability of chlorination to reduce the numbers of a spectrum of 

marine organisms and to estimate the minimum chlorination concentrations as measured by 

TRO revealed that chlorination was effective in removing bacteria, phytoplankton, and 

mesozooplankton with initial TRO concentrations of 3 mg/L. Persistence of TRO resulted in 

an extended period of toxicity and cumulative mortality. 

As shown in section 3.2, the initial field TRO level of ballast water treated with PurimarTM

System was satisfied with this condition. 

Various reports confirm that TRO can induce rapid mortality to marine organisms, but 

comparisons of specific effect concentrations are complicated by the variety of exposure 

times and oxidant measurement methods used in each study. A recent study was reported 

that LC50 values of the most sensitive organism tested, juvenile topsmelt was 0.38 mg/L 

TRO, and juvenile sheepshead minnows were nearly as sensitive (0.35 mg/L TRO). 

The study sought to evaluate the effects of exposing Rotifer, Brachionus plicatilis to residual 

oxidants in seawater indicated that survival of the rotifers was affected significantly only 

when TRO values were higher than 0.22 mg/L, which would be considered the no observable 

effect concentration (NOEC). In our all WET tests, similar results were observed. 

As shown in section 3.2, the TRO level measured at field showed an initial increase and 

subsequent decrease in concentration presumably due to back reactions as the reaction time 

increased. Chlorine and bromine residual would likely be maintained or degrade slowly in 

chlorinated ballast waters for a limited time period and would continue to have a biocidal 

effect if chlorinated waters remain in dark ballast tanks. However, the results of WET test of 
MEPC 61/2 

Annex, page 35 

I:\MEPC\61\2.doc 

neutralized ballast water discharge against aquatic organisms, being primary producers, 

consumers and predators showed that even the full strength effluent of the PurimarTM System 

did not have any deleterious effects on any of the test species (NOEC values of ≥ 100% 

discharged ballast water containing TRO concentration lower than 0.1 mg/L). 

Therefore, it is conclusively to say that although chlorination is identified as having the most 

potential for risk to aquatic organisms, WET testing results of discharged ballast water 

suggest that potential risk is absent. 

6.3.6 Effects on aquatic organisms 

Although no significant chemicals identified as potential ecotoxic substances were found in 

the treated ballast water of PurimarTM System, appropriate Predicted No-Effect 

Concentrations (PNEC) is derived for Active Substance, Other Chemical and Relevant 

Chemicals that may be of concern for the aquatic environment. 

PNEC values are estimated from short-term and/or long-term aquatic toxicity data for 

relevant aquatic species by dividing the lowest available effect concentration with an 

appropriate assessment factor as shown in Table 6.7. (See the complete confidential 

dossier.) Although a thorough literature review of available data was performed and 

summarized in Tables 3.23 and 3.24, some dataset was limited and did not meet validity 

criteria. Other dossiers submitted for Procedure (G9) approval also used incomplete datasets 

for fish, crustaceans, and algae for the derivation of the individual PNEC value. When a 

complete and valid dataset was not obtained from the literature review, the lowest effect 

concentration reported was utilized for PNEC derivation. 

The resulting PEC/PNEC ratios of Active Substance, Other Chemical, and Relevant 

Chemicals are indicated in Tables 6.8 and 6.9. (Full data detailed in the complete confidential 

dossier.) 

Table 6.8: PEC/PNEC ratios of case 1 

Emission 

Conc. Emission PEC 

Assessment 

factor 

Endpoint PNEC PEC / 

Chemical name PNEC 

(mg/L) (g/day) (μg/L) ( - ) (mg/L) (μg/L) ( - ) 

TRO (without 

neutralization) 3.00000 842,382.00 8.04E+00 100 0.1 1 8.04E+0

0 

TRO (with neutralization 

0.1ppm) 0.10000 28,079.40 2.68E-01 100 0.1 1 2.68E-01 

Chlorodibromomethane 0.01640 4,605.02 3.91E-02 1000 34 34 1.15E-03 

Tribromomethane 0.38100 106,982.51 9.41E-01 1000 1 1 9.41E-01 

Monochloroacetic acid 0.02160 6,065.15 6.21E-02 1000 0.07 0.07 8.87E-01 

Monobromoacetic acid 0.00540 1,516.29 1.48E-02 1000 0.2 0.2 7.40E-02 

Dichloroacetic acid 0.01620 4,548.86 4.66E-02 1000 23 23 2.03E-03 

Trichloroacetic acid 0.03890 10,922.89 1.17E-01 1000 1.2 1.2 9.75E-02 

Bromochloroacetic acid 0.00594 1,667.92 1.71E-02 1000 0.07 0.07 2.44E-01 

Dibromoacetic acid 0.04300 12,074.14 1.24E-01 1000 69 69 1.80E-03 

Bromodichloroacetic acid 0.00277 777.80 7.96E-03 1000 23 23 3.46E-04 

Dibromochloroacetic acid 0.00368 1,033.32 1.06E-02 1000 23 23 4.61E-04 

Tribromoacetic acid 0.01040 2,920.26 2.99E-02 1000 5.61 5.61 5.33E-03 

Dichloroacetonitrile 0.00056 157.24 1.67E-03 1000 0.55 0.55 3.04E-03 

Dibromoacetonitrile 0.05170 14,517.05 1.55E-01 1000 0.55 0.55 2.82E-01 

Sodium thiosulfate 9.00000 2,527,146.0 2.79E+01 1000 805 805 3.47E-02 

NOTE: The estimated ratios between predicted concentrations of the Active Substance, Other Chemical, or Relevant 

Chemicals and the respective PNEC values are all below 1. This, together with the results of WET tests, indicates that 

no further assessment of direct toxic effects to the aquatic environment is necessary. 
MEPC 61/2 

Annex, page 36 

I:\MEPC\61\2.doc 

6.3.7 Effects on sediment 

As shown in section 3.4, there are no effects on sediment for the chemical and properties of 

the substances of PurimarTM System. 

6.3.8 Comparison of effect assessment with discharge toxicity 

A major concern following treatment of ballast water with any biocide is the discharge of 

potentially toxic chemicals to the environment. Acceptable ballast treatment for the 

prevention of non-indigenous species must be able to remove viable organisms from the 

ballast water and upon discharge be non-toxic to the receiving waters. 

For the PurimarTM System, chlorination-induced oxidant is most likely to exist for any 

extended period of time, in concentrations potentially harmful to marine organisms. Various 

disinfection by-products were identified as possible constituents of toxicological importance 

in the PurimarTM System treated ballast water, however, they did not reach toxic levels in the 

residual ballast water. Thus, chlorination-induced residual oxidant, as measured by TRO, is 

thought to be the only effective by-product that persists long enough to have been measured 

in the toxicity tests. However, a potential problem and alternatively an attractive feature of 

chlorination treatment of ballast water is that the concentration of TRO in seawater declines 

over time. It should be noted that the chemistry and toxicity of chlorination of seawater is 

strongly affected by the chemistry of the water (e.g., TOC, temperature, pH, salinity and 

sediment loading), and the chlorine and bromine residues are extremely labile in sunlight and 

would not persist long in the environment, thus oxidant concentrations diminish quickly in 

chlorinated seawater exposed to the atmosphere. 

The results of the WET tests indicated that test substances prepared from water samples 

taken immediately after treatment of the PurimarTM System (T0), showed residual toxicity. 

At that time point, the practical result indicates that the laboratory TRO level immediately on 

delivering was much lower than the corresponding field level at 5 hours after completion of 

chlorination. Furthermore, the laboratory TRO level after filtration was dramatically reduced. 

These results suggest that chlorination-induced oxidants may dissipate very quickly from 

samples that are exposed to sunlight and atmosphere and bubbled with ambient air. 

Our experiments may have underestimated the efficacy of chlorination resulting from the 

laboratory TRO level and possible residual toxicity of chlorination-induced residual oxidant 

over time. Therefore, the PurimarTM System was equipped with neutralizing unit, and the final 

discharged ballast water was dechlorinated with sodium thiosulfate to maintain the TRO 

concentration below 0.1 mg/L. All toxicity tests using neutralized water samples regardless of 

residual TRO concentration showed no residual toxicity. 

Therefore, it is conclusively to say that the PurimarTM System is an excellent ballast water 

management system which prevents non-indigenous species from the influent ballast water 

and maintains non-toxic to the receiving waters upon discharge. 

7 RISK ASSESSMENT 

7.1 Risk to safety of ship 

A risk analysis will be conducted by the Korean Registry of Shipping to demonstrate that the 

PurimarTM System is acceptable for installation on TWECO test barge. A qualitative 

comparative analysis will be conducted for the chemical dosing and ballast water sampling 

systems involved in the installation. 
MEPC 61/2 

Annex, page 37 

I:\MEPC\61\2.doc 

Further, the PurimarTM System will be certified for shipboard installation by the Korean 

Registry of Shipping, in compliance with international design and construction standards for 

ship safety. 

7.1.1 Corrosion 

Corrosion in metal and steel is the important concern to the ship industry. This is why a 

majority of the surfaces internal to the ship and in contact with seawater such as piping and 

tanks are coated with protective paints and coatings. Tests of how well these paints and 

coatings protect metal and steel surfaces are completed by various organizations and 

coating vendors. 

Now we will conduct corrosion testing with Korea Testing & Research Institute (KTR) 

applying IMO standard during land-based testing and the results will be reported in the Final 

Approval dossier. 

Referring to the report of the eighth meeting of the GESAMP-Ballast Water Working Group 

document and in progressing an experiment, corrosion test should include uncoated 

substrates and marine epoxy coated steel. Coatings should be in accordance with the 

IMO Performance standard for protective coatings for dedicated seawater ballast 

tanks in all types of ships and double-side skin space of bulk carriers 

(MEPC 59/2/16, GESAMP-BWWG 8/6, paragraph 5.1.1.1; MSC.215(82)). 

7.1.2 Fire and explosion (formation of gases) 

Potential fire and explosion risks associated with the PurimarTM System are related to the 

hydrogen gas generated during the electrochemical process, the sodium thiosulfate 

(neutralizing agent) stored on board or electrical components of the system. 

The PurimarTM System will generate hydrogen gas as a by-product during producing sodium 

hypochlorite. Hydrogen gas can be explosive at concentrations >4% volume in air. 

The PurimarTM System has several safety mechanisms that are engineered into the system 

to ensure that hydrogen gas is effectively removed from the ship. These include a patented 

cyclone separator device that removes the hydrogen gas from the biocide solution and air 

blowers to reduce the concentration of hydrogen gas to <1% (well below the 4% Lower 

Explosive Limit) within a vent line to the air outside the ship. Additionally, a hydrogen gas 

detector is located in the space(s) where hydrogen gas may enter should a PurimarTM

System failure occur. The monitor and control will manage all of these safety features and 

will result in an alarm condition should the system require maintenance. 

Hydrogen and chlorine gas will be measured during land-based test run, and the results will 

be submitted in the final report. 

Sodium thiosulfate is a non-flammable, stable liquid. Excessive heating and/or contact with 

acids can liberate sulfur dioxide fumes, but does not create a fire hazard. 

The PurimarTM System is already adopting the proven electrical components by 

Classification Society such as KR, ABS, DNV, LR, and GL. So, these components already 

met the existing safety guideline of Classification Societies. A part of electrical component 

which is not certified will be also tested and certified by Classification Society. 

Considering the above safety measures, the fire and explosion risk in the PurimarTM System 

on board is very low. 
MEPC 61/2 

Annex, page 38 

I:\MEPC\61\2.doc 

7.1.3 Storage and handling of the substances 

As shown in section 3.1.4, the only chemical needs storage in the PurimarTM System is 

Sodium thiosulfate as neutralizing agent. Sodium thiosulfate is non-flammable and there is 

no possibility of fire risk on board as above-mentioned. The storage tank will be designed 

according to the guideline of Classification Society and the PurimarTM System including 

installation of storage tank will be certified by Classification Society. Consequently, the 

potential risks to the ship due to chemical storage are very low. 

7.2 Risks to human health 

The health risks to all recipients from the PurimarTM System under normal operating 

conditions are very small and well within acceptable levels. Even an TWECO technician, 

exposed to concentrated sodium thiosulfate during a spill during chemical resupply, and who 

is not wearing PPE (Personal Protective Equipment) – an unlikely scenario – would have low 

health risk. Cancer risk and non-cancer hazards for the general public/beachgoers are well 

below levels of concern; actual risks to these recipients are expected to be even lower, as 

they are unlikely to be repeatedly exposed to treated ballast water as assumed in this risk 

evaluation. Since the risk assessment only evaluated direct exposure via ingestion and 

dermal contact with chemicals or ballast water, as these were considered the most relevant 

pathways, further semi-qualitative evaluation of the inhalation pathway was performed for the 

volatile THMs. This assessment demonstrated that conservative concentrations of airborne 

THMs generated by a release of ballast water were well below occupational exposure limits. 

Full details are contained in appendix 8 "Human Exposure Assessment". 

7.2.1 Risk Characterization 

Risk characterization is a summary for the risk assessment components and serves to 

outline the key findings and inform the risk manager in public health decisions. It is an 

analysis and integration of the conclusions from the hazard assessment, the exposure 

assessment, and the health effect assessment. 

7.2.1.1 Risk characterization during normal operation 

Risk characterization for the operator during ballasting 

Under normal operation, the system is to be considered as a closed circuit. There is no 

exposure to the in situ production of biocide solution, treated ballast water itself, or stored 

sodium thiosulfate in storage tanks. It is conclusive to say that there is no health risk for the 

operator during normal operation. 

Risk characterization for the crew, dock workers, and general public during ballasting 

The low concentrations of COPCs in ballast water compared to WHO guidelines for drinking 

water and U.S. OSHA PELs indicate that the health risk related to inhalation of tank air for 

persons on deck is very low. It is worth noting that exposure to tank air is less frequent and of 

lower intensity than exposure to drinking water vapours, which should imply that the risk 

characterization is conservative. Therefore, it is conclusive to say that there is no need for 

risk mitigation measures. 
MEPC 61/2 

Annex, page 39 

I:\MEPC\61\2.doc 

If the wind directs the released tank air to the nearby port/coast, third party in the port/coast 

can be exposed to the tank air. Because the THMs in vent air would quickly dissipate into the 

atmosphere, it is anticipated that air exposures will decrease as distance to the ballast water 

increases; therefore, potential air exposures for dock workers and the general public in the 

third party would be even less than those for the ship’s crew. 

Risk characterization for the operator and crew during deballasting 

There is no exposure to the operator or crew during discharge of ballast water as the ballast 

water is discharged under sea level. 

Risk characterization for the general public during deballasting 

The chemicals identified in this risk assessment all have Log Kows less than 3 and BCFs 

less than 2000. Hence, these compounds will not be found in seafood. As a result, there is 

no health risk connected to consumption of seafood taken from areas where ballast water is 

discharged. 

Most chemical compounds in treated ballast water are much lower in concentrations than the 

WHO guidelines for drinking water quality to assess the health risks in connection with 

swimming at beaches near areas where treated ballast water has been discharged from the 

ship. Although bromoform is found to be higher than the guideline, its concentration will be 

dramatically reduced in the swimming point as the plume of ballast water will be diluted in 

seawater when discharged to sea. As it is highly unlikely that the general public would 

recreate very close to docked ships, the health risk in connection with swimming in the 

vicinity of ships discharging ballast water is assessed as very low. 

7.2.1.2 Risk characterization during maintenance of the ballast water tanks 

Although the volatile THMs produced as disinfectant by-products could be inhaled near 

ballast water or vent air outlets, existing procedures for work in a tank means that any volatile 

gas in the tank due to ballast water treatment will not pose any additional health risk to 

personnel entering the tank. Furthermore, the potential exposures and risks associated with 

vent air during ballasting and de-ballasting are discussed in the above section, and it is 

concluded that, there is no need for additional risk mitigation measures. 

7.2.1.3 Risk characterization during system maintenance and accidental situations 

The operator of the PurimarTM System could have direct contact with COPCs within the 

system during maintenance activities and to sodium thiosulfate during chemical resupply 

activities. And the ship's crew including the operator could have oral and dermal exposure to 

the treated ballast water in tanks. 

Although the COPCs generated in situ at aqueous concentrations are at concentrations too 

low to cause serious eye and skin irritation, direct contact to whatever volume that is spilled 

may cause minor irritation to the eyes, sensitive skin and throat. Conventional personal 

protective equipment (PPE; i.e. gloves, and goggles) is considered adequate in order to 

minimize the potential for these acute health effects. Only trained personnel should be 

handling the concentrated solution. In case of ventilation breakdown or leakage, there is a 

risk of vapour or fumes to be released. These fumes may cause dizziness and nausea, and 

inhalation should be avoided. Respiratory protection should be available. As the acute health 

effects of COPCs are easily preventable, the risk to acute human health is considered to be 

low. 
MEPC 61/2 

Annex, page 40 

I:\MEPC\61\2.doc 

The more critical endpoint for potential exposure to ballast water COPCs at low 

concentrations are chronic health issues. Thus, health effect assessment of COPCs 

exposures against ship's crew including the operator of the PurimarTM System are evaluated 

quantitatively in the appendix 8. The US EPA states that action is generally not warranted at 

a site when the cumulative non-carcinogenic hazard index is less than 1.0, and uses a 

potential excess individual lifetime cancer risk of 1 x 10-6 (1 in 1,000,000) as a point of 

departure for risk management actions. As shown in Tables 7 and 8, the total 

non-carcinogenic hazard indexes of the operator and ship's crew are 0.237 and 0.0000977, 

respectively, which are well below the level of concern. And as shown in Tables 9 and 10, 

the total estimated cancer risk of the operator and ship's crew are 3.9 x 10-9

(3.9 in 1,000,000,000) and 3.35 x 10-9 (3.35 in 1,000,000,000), respectively, which are far 

below the US EPA point of departure. 

It is believed that the potential risks presented in appendix 8 would be considered the 

worst-case estimates. The actual health risks to the populations of the exposures to 

chemicals associated with the PurimarTM System are to be even lower, as they are unlikely to 

be repeatedly exposed to COPCs as assumed in this risk evaluation. In addition, the use of 

conventional personal protective equipment and safe chemical handling procedures will 

further reduce any potential exposures and associated effects. 

7.3 Risks to the aquatic environment 

The data for the substances associated with use of the PurimarTM System indicate that there 

is a low potential for bioaccumulation, sediment adsorption, and persistence in the aquatic 

environment. No effects or risks in the form of secondary (food chain) poisoning or to 

sediment species are anticipated. As such, toxicity presents the only likely potential risk for 

aquatic organisms. 

Whole effluent toxicity testing (acute and sub-lethal endpoints) of neutralized ballast water 

discharge indicates no apparent toxicity for all species and endpoints tested (L(E)C50 and/or 

NOEC values of ≥100% ballast water sample). 

To ensure that no risks can be expected from the neutralizing agent, further chronic toxicity 

testing was conducted with repeated dosing of ballast water neutralized with a large excess 

of sodium thiosulfate. Water samples were prepared by diluting the biocide solution 

generated from the TWECO laboratory-scale electrolytic apparatus with commercial 

seawater to a 1 mg/L of TRO, and then neutralizing with a 2.36 mg/L of sodium thiosulfate. 

Seven repeated dosing of freshly prepared water samples including a total of 16.52 mg/L 

sodium thiosulfate, which is much larger than would normally be applied, showed no toxicity 

(see Table 3.21). 

Therefore, the toxicity testing of the treated ballast discharge indicates that unacceptable 

risks to the aquatic environment are not expected from use of the PurimarTM System. 

8 ASSESSMENT REPORT 

8.1 Overview of data and endpoint 

The constituents associated with the PurimarTM System were evaluated for a variety of 

endpoints, including toxicity, bioaccumulation, and persistence in the environment. 

The physical and chemical properties were evaluated to assess proper chemical handling 

and/or storage in a shipboard setting, and risks such as fire/explosion. Treated ballast water 

discharge and the risks of the COPCs to human health were also evaluated. 
MEPC 61/2 

Annex, page 41 

I:\MEPC\61\2.doc 

As the Active Substance is generated on board as required and neutralized prior to 

discharge, it is the treated ballast water and DBPs potentially present that are the most 

important to consider for this evaluation. 

Whole effluent discharge toxicity testing has been conducted for different water types at 

various Active Substance treatment and TOC levels, and at different holding times. 

As expected, toxicity was observed for all species in the samples collected immediately after 

hypochlorite treatment (Day 0). Some toxicity was observed in the Day 2 and Day 5 

pre-neutralization samples. However, in all species tested, no toxicity was observed in the 

Day 2 and Day 5 post-neutralization samples concomitantly with non-detectable TRO. 

During the preliminary and land-based test runs of the PurimarTM System meeting ballast 

water performance standard concerning biological efficiency, the amount of Active 

Substance and Relevant Chemicals were measured. The evaluation of the toxicological, 

chemical, and physical properties of all chemicals obtained from eminent literatures and 

databases suggest that bioaccumulation, sediment adsorption, or persistence is not 

expected to occur. Further, none of the chemicals met all three PBT substance criteria. 

The DBP concentrations from the studies noted above consider analysis of the whole effluent 

only and do not reflect actual environmental concentrations when treated ballast water is 

released in a harbour where dilution and mixing will occur. The PEC in the port of Busan was 

predicted by using the modelling of MAMPEC and the PNEC was determined from the 

selected aquatic toxicity data and assessment factors. The PEC/PNEC ratio of all chemicals 

in ballast water treated with the PurimarTM System, were below 1 even at the worst case 

emission scenario. 

Potential human exposures and health effects were evaluated qualitatively and quantitatively, 

when possible. Overall, the risk assessment determined risks to all recipients from 

the PurimarTM System under normal operating conditions are very small and well within 

acceptable levels. 

8.2 Quality of the test reports 

Both the efficacy and toxicity (including chemical analysis) testing complied with 

Guidelines (G8) and Procedure (G9) requirements regarding quality control, including the 

implementation of a comprehensive QAPP. 

The quality assurance (QA) team of Dong A University (DAU) GLP Centre provided support 

and guidance in developing QAPP, and also provided technical review comments on the test 

reports, to assist in assessing their quality. DAU GLP centre is certified to Principles of Good 

Laboratory Practice by the Korea Food and Drug Administration, National Institute of 

Environmental Research, and Rural Development Administration. 

Quality of the test reports is further assured by the fact that Busan Techno-Park Marine 

Bio-industry Development Centre (MBDC), which undertook the efficacy and toxicity testing, 

maintains QA certification of the Korean Laboratory Accreditation Scheme (KOLAS) for 

ISO/IEC 17025; and SGS testing Korea, which undertook chemical analysis, also maintains 

QA certification of KOLAS for ISO/IEC 17025 and National Environmental Laboratory 

Accreditation Program (NELAP), which is the program that implements the National 

Environmental Laboratory Conference standards, States and Federal agencies serve as 

Accreditation Authorities with coordination currently facilitated by US EPA to assure 

uniformity. 
MEPC 61/2 

Annex, page 42 

I:\MEPC\61\2.doc 

For the study of risk assessment, a variety of reputable sources were consulted to gather test 

data and conduct the assessments required. These sources include, but are not limited to 

WHO, IPCS, OECD and US EPA. Information was also gathered from published 

independent research, which in most cases is peer-reviewed by others with similar levels of 

expertise. In some cases the test method used was not specified; however if the dataset was 

limited, this data was included to provide at least some information. Due to the primary 

sources relied upon during the evaluation; the level of uncertainty with this assessment is 

low. 

9 REFERENCES 

See the complete confidential dossier. 

10 APPENDICES 

Appendix 1: Key Data Summary 

Appendix 2: Certificates of TWECO and Test Facilities 

Appendix 3: Quality Assurance Project Plan (QAPP) 

Appendix 4: Test Report on Toxicity and Efficacy by MBDC 

Appendix 5: Test Report on Chemical Analysis by SGS 

Appendix 6: Material Safety Data Sheets 

Appendix 7: PurimarTM BWMS Manual 

Appendix 8: Human Exposure Assessment 

(See the complete confidential dossier.) 

_____________