Ballast Water Treatment Advisory
Our Mission

The mission of ABS is to serve the public interest as well as the 

needs of our clients by promoting the security of life, property 

and the natural environment primarily through the development 

and verifi cation of standards for the design, construction and 

operational maintenance of marine-related facilities.

Quality & Environmental Policy

It is the policy of ABS to be responsive to the individual and 

collective needs of our clients as well as those of the public at 

large, to provide quality services in support of our mission, and 

to provide our services consistent with international standards 

developed to avoid, reduce or control pollution to the environment.

All of our client commitments, supporting actions, and services 

delivered must be recognized as expressions of Quality. We pledge 

to monitor our performance as an on-going activity and to strive for 

continuous improvement.

We commit to operate consistent with applicable environmental 

legislation and regulations and to provide a framework for 

establishing and reviewing environmental objectives and targets.
ABS BALLAST WATER TREATMENT ADVISORY • 1

Ballast Water Treatment Advisory

Table of Contents

Introduction

I. Regulatory Developments

a. International Regulatory Status (IMO)

b. Overview of Some Regional, National & Local Regulations

II. BWT Technologies

 a. Overview of Treatment Technologies

 b. Treatment System Approval by IMO & Member States

III. BWT Considerations

 a. Considerations for Selection of Treatment Systems

 b. Treatment Technology Factors

 c. General Treatment System Considerations

 d. Challenges for Installation Engineering

IV. Evaluation Checklists

 a. Vessel Ballast System Particulars – Owner Supplied Data

 b. Ship & Service Characteristics that Impact BWT Selection – 

Owner Supplied Data

 c. Treatment Technology Factors – Vendor Supplied Data

 d. General Treatment System Considerations – Vendor Supplied Data

 e. Challenges for Installation Engineering – Owner Supplied Data

Appendix: Technical Information for Ballast Water Treatment Systems

Disclaimer

The development and approval of ballast water treatment systems is a dynamic process. 

The information contained in this ABS Advisory Notice should not be construed as being 

all encompassing and readers are urged to contact ABS or review the latest IMO information 

available to determine the extent to which the status of the various systems included here 

may have changed and if other systems have been proposed for review and approval.
2 • ABS BALLAST WATER TREATMENT ADVISORY

T

he ballast water and sediments carried 

by ships have been identifi ed as a major 

pathway for the transport of harmful 

invasive aquatic organisms and pathogens. 

Ships often take on ballast water in one port 

and carry such ballast to other ports where it 

is discharged. The ballast water and sediments 

contain living organisms which, despite the 

harsh conditions in the ballast tanks and piping 

systems, survive to compete with native species 

in the port of discharge. If the non-native 

organisms have few natural predators or other 

natural controls they may become invasive 

and change the local ecosystems, sometimes 

dramatically. 

The direct economic impact of aquatic invasive 

species, as well as the potential long term 

damage to the health of the local marine 

environment and the people who depend on 

that environment has been well documented. 

International, national and regional regulations 

have been implemented to control the transport 

of the aquatic organisms. The current efforts 

rely on ballast water management (BWM) 

practices, including ballast exchange, and other 

measures aimed at preventing or minimizing 

the uptake and discharge of contaminated water 

or sediment when ballasting or deballasting. 

These methods may not be completely effective in 

preventing invasive species and furthermore are 

often not required if the safety of the vessel would 

be at risk during the exchange. Systems that treat 

ballast water to remove or kill organisms are not 

only potentially more reliable but are designed 

and installed to achieve measurable effi cacy levels 

while protecting vessel safety. 

This ABS Advisory has been produced to 

summarize the current state of ballast water 

treatment regulations and available technologies 

in order to provide useful guidance to shipowners, operators, and builders as they make 

decisions about suitable treatment options. 

This Advisory contains fi ve sections:

Introduction

Section 1 Regulatory Developments

Section 2 Overview of Treatment Technologies

Section 3 Considerations for System Selection, 

Installation and Operation

Section 4 Evaluation Checklists

Appendix Available Systems
ABS BALLAST WATER TREATMENT ADVISORY • 3

Section 1: 

Regulatory 

Developments

International Regulatory Status 

(IMO)

In 2004, the IMO adopted the International 

Convention for the Control and Management 

of Ships’ Ballast Water and Sediments. The 

Convention calls for ships to conduct a ballast 

water exchange or to meet a concentration-based 

ballast water discharge standard in accordance with 

a gradually implemented schedule linked to the 

ship’s build date and the amount of ballast carried 

on board the ship. 

Acceptance of the Convention has been slow. 

Entry into force will occur 12 months after ratifi cation by 30 States representing 35 percent of world 

merchant shipping gross tonnage. The current 

information on ratifi cation is included in Table 1. 

Because of the slow pace of adoption, the implementation deadlines written into the Convention 

have become obsolete before they could become 

mandatory. This has required adjustments to the 

implementation schedule. This uncertain regulatory schedule makes it all the more diffi cult for 

owners, builders and manufacturers to plan for 

the necessary equipment. 

Until such time as the Convention enters into force 

and the implementation schedule becomes binding 

globally, actions to address the issue of invasive 

species are increasingly occurring at national, 

regional and local levels. More than a dozen 

individual nations, in addition to regions as diverse 

as northwest Europe, the Great Lakes, ROPME 

Sea Area and Antarctica, have 

introduced specifi c regulations 

addressing the discharge of 

ballast in their waters. Further 

complicating the issue, 

government authorities such as 

those in California, Michigan, 

New York and others within 

the US, and the State of 

Victoria in Australia, have 

introduced local ballast water 

management requirements. 

A small number of these 

jurisdictions may prohibit the discharge of ballast 

water entirely (e.g. Panama within the Panama 

Canal), require chlorination (e.g. Buenos Aires), or 

restrict in-port discharge to an approved onshore 

reception facility.

Owners are encouraged to contact their relevant 

fl ag State, port agents or shipowner association 

for the latest specifi c information on national 

or regional requirements as new and additional 

requirements are being mandated. The following 

sections provide information on the requirements 

for treatment as outlined in the IMO Convention. 

A few signifi cant regional developments are also 

provided.

Applicability of the IMO BWM Convention

The 2004 IMO BWM Convention applies to all 

vessel types operating in the aquatic environment 

which are designed to carry ballast water and 

are entitled to fl y the fl ag of a Party to the 

Convention. This includes submersibles, fl oating 

craft and platforms including fl oating storage 

units (FSUs) and fl oating production storage and 

offl oading units (FPSOs), although the applicable 

requirements vary. Refer to Table 1 for a list of 

Parties to the Convention.

IMO BWM Convention Treatment Standards 

The Convention includes two regulations that 

defi ne ballast water management standards; 

Regulation D-1 addresses the Ballast Water 

Exchange standard and Regulation D-2 details the 

Ballast Water Treatment Performance standard.

Ballast water exchange is founded on the principle 

that organisms and pathogens contained in ballast 

water taken on board from coastal waters will not 

survive when discharged into deep oceans or open 

seas, as these waters have different temperatures, 

salinity and chemical composition. Similarly the 

deep ocean waters or open seas, when compared 

Table 1: Status of Ratifi cation of the IMO BWM Convention

(As of 15 April 2011)

States % Tonnage Parties to the Convention:

Needed: 

30

Needed: 

35%

Albania, Antigua and Barbuda, Barbados, 

Brazil, Canada, Cook Islands, Croatia, Egypt, 

France, Iran, Kenya, Kiribati, Republic of Korea, 

Liberia, Malaysia, Maldives, Marshall Islands, 

Mexico, Netherlands, Nigeria, Norway, Saint Kitts 

and Nevis, Sierra Leone, South Africa, Spain, 

Sweden, Syrian Arab Republic and Tuvalu.

Currently: 

28

Currently: 

25.43%
4 • ABS BALLAST WATER TREATMENT ADVISORY

Ballast 

Cpty 

(m3

)

Build 

Date

*First Intermediate or Renewal Survey, whichever occurs fi rst, after the anniversary date 

 of delivery in the respective year

2009 2010 2011 2012 2013 2014 2015 2016 2017

< 1,500

< 2009

in 2009 Note: D-1; D-2 by 2nd Annual but not beyond 31 Dec. 2011 or EIF, whichever is later

> 2009 D-2 (at delivery or EIF, whichever is later)

> 1,500

or 

< 5,000

< 2009

in 2009 Note: D-1; D-2 by 2nd Annual but not beyond 31 Dec. 2011 or EIF, whichever is later

> 2009 D-2 (at delivery or EIF, whichever is later)

> 5,000

< 2012

> 2012

to the coastal waters, contain fewer organisms 

and pathogens and those that do exist are less 

likely to adapt to the new coastal or freshwater 

environment. Therefore the probability of 

organism and pathogen transfer through ballast 

water is signifi cantly reduced.

Ships performing ballast water exchange are 

required to do so with an effi ciency of at least 

95 percent volumetric exchange. Acceptable 

methods for ballast water exchange are the 

Sequential Method, the Flow-through Method 

and the Dilution Method. 

Noting that ballast water exchange presents 

signifi cant operational concerns and challenges, 

and that it may not provide a totally effective 

solution to reduce the spread of unwanted 

aquatic organisms and pathogens from ships’ 

ballast water over time, the Convention requires 

an upgrade to the installation of ballast water 

treatment systems in accordance with a specifi ed 

schedule. 

Regulation D-2 defi nes the performance standard 

for the ballast water treatment system. This 

criterion is in the form of specifi c limits on 

aquatic life in the ballast discharge:

Ships conducting ballast water management in 

accordance with this regulation shall discharge:

• Less than 10 viable organism per m3 > 50μ in 

minimum dimension, and 

• Less than 10 viable organisms per ml < 50μ 

and >10μ in minimum dimension, and

• Less than the following concentrations of 

indicator microbes:

 – Toxicognic Vibrio cholera less than 

1 colony forming unit (cfu) per 100 ml, 

or less than 1 cfu per 1 gram zooplankton 

samples

 – Escherichia coli less than 250 cfu per 100 ml

 – Intestinal Enterococci less than 100 cfu 

per 100 ml 

The D-2 standard is the metric used to measure 

the effi cacy of the treatment system and it applies 

to the system as installed on board and used in 

actual operations. All treatment systems must 

be type approved by an Administration under a 

robust protocol which requires that they satisfy 

this standard in full scale operations. In any 

port or offshore terminal, an offi cer authorized 

by a Party to the Convention may board a vessel 

to which the Convention applies and test the 

ballast water discharge for compliance by taking 

samples.

IMO BWM Convention Compliance Timeframe

Table 2 indicates the implementation schedule 

as detailed in Regulation B-3 of the International 

Convention for the Control and Management 

of Ships’ Ballast Water and Sediments, 2004 as 

revised by IMO Resolutions A.1005(25) and 

MEPC.188(60). These resolutions were adopted 

as a result of the review of the entry into force 

provisions and the development and availability 

of type approved ballast water treatment 

technologies. 

Table 2: IMO BWM Convention Implementation Schedule

Revised per Resolution A.1005(25) & MEPC.188(60)

D-1 or D-2 D-2*

D-2*

D-2*

D-1 or D-2

D-1 or D-2

N/A D-2 (at delivery or EIF, whichever is later)

Note: EIF = Entry into force
ABS BALLAST WATER TREATMENT ADVISORY • 5

It was noted at the 59th session of the IMO Marine 

Environmental Protection Committee that there 

are a suffi cient number of type approved ballast 

water treatment technologies available for ships 

constructed in or after 2009 that have a ballast 

water capacity of less than 5,000 m3

. Resolution 

MEPC.188(60) conveys the committee’s position 

that while the requirements of the regulation 

cannot be enforced before the entry into force of the 

BWM Convention, it should be clearly understood 

that the ballast water management systems installed 

on ships constructed in 2010 must comply with the 

ballast water performance standard once the BWM 

Convention is ratifi ed. At MEPC 61, the Committee 

agreed that a new review of ballast water treatment 

technologies, focused on larger ships with a ballast 

water capacity of 5,000 m3

 or more (in particular 

those with higher fl ow rate) would be necessary 

when it reconvened at MEPC 62 in July 2011.

Additional clarifi cation regarding the application 

dates for ships constructed before 2009, Regulation 

B-3.1 of the BWM Convention, can be found in 

IMO BWM.2/Circ.29. This circular revokes BWM.2/

Circ.19 and builds on the experience gained during 

the implementation of Regulations 20 and 21 of 

MARPOL Annex I. IMO BWM.2/Circ.29 confi rms 

that the “anniversary date of delivery of the ship 

in the year of compliance” specifi ed in Regulation 

B-3.2, refers to years 2014 and 2016 indicated in 

Regulation B-3.1. 

Consequently, ships with a ballast water capacity 

between 1,500 and 5,000 m3

 inclusive are required 

to comply with the D-2 standard not later than the 

fi rst intermediate or renewal survey, whichever 

occurs fi rst, after the anniversary date of delivery 

of the ship in 2014 under Regulation B-3.1.1. Ships 

with a ballast water capacity of less than 1,500 m3

or greater than 5,000 m3 are required to comply 

with the D-2 standard not later than the fi rst 

intermediate or renewal survey, whichever occurs 

fi rst, after the anniversary date of the delivery of the 

ship in 2016 under Regulation B-3.1.2.

The following examples are instructive in how to 

interpret Table 2.

• A ship with a ballast water capacity less than 

5,000 m3 constructed in 2009 will not be 

required to comply with D-2 standard until 

its second annual survey but not later than 31 

December 2011. (Res.A.1005(25))

• A ship with a ballast water capacity of less 

than 5,000 m3 constructed after 2009 must be 

equipped with a type approved ballast water 

treatment system that meets the D-2 standard 

upon delivery or EIF, whichever is later. 

(Res.MEPC.188(60))

• A ship with a ballast water capacity of greater 

than 5,000 m3 constructed before 2012 is 

to be equipped with a type approved ballast 

water treatment system that meets the D-2 

standard not later than the fi rst intermediate or 

renewal survey, whichever occurs fi rst, after the 

anniversary date of delivery of the ship in 2016. 

(BWM.2/Circ.29)

Owners and operators are encouraged to consult 

with representatives from the local ABS technical 

offi ces for additional clarifi cation once the entry 

into force criteria have been satisfi ed.

IMO Activity Related to the 2004 Convention

At MEPC 61, the committee approved the framework for determining when a basic approval 

granted to one ballast water management system 

may be applied to another system that uses the 

same active substances or preparation (BWM.2/

Circ.27). In addition, guidance for Administrations 

on the type approval process for ballast water 

management systems in accordance with the G8 

guideline was approved (BWM.2/Circ.28).

IMO invited member governments and observers to 

propose practical solutions to the challenges of the 

BWM Convention, in relation to some special types 

of ships, in particular seagoing unmanned barges, 

semisubmersibles and heavy lift crane vessels. The 

committee urged member States to apply, as soon 

as possible, the provisions of Resolution MEPC. 

188(60), which encourages member governments 

to install ballast water treatment systems on new 

ships in accordance with the application dates 

contained in the BWM Convention.
6 • ABS BALLAST WATER TREATMENT ADVISORY

IMO Guidelines Available 

Since the adoption of the Convention, IMO has 

been working to develop a series of guidelines that 

further clarify and expand upon the requirements 

put forward in the Convention. All 14 of the 

planned guidelines have been completed and 

are available from IMO. A list of the guidelines 

supporting the Ballast Water Convention is as 

follows: 

G1 Sediment Reception Facilities

 MEPC.152(55)

G2 Guidelines for Ballast Water Sampling

 MEPC.173(58)

G3 BW Equivalent Compliance 

 MEPC.123(53)

G4 BWM and the Development of BWM Plans

 MEPC.127(53)

G5 BW Reception Facilities 

 MEPC.153(55) 

G6 BW Exchange – Operational 

 MEPC.124(53)

G7 Risk Assessment under Regulation 4-A 

of the BWM Convention 

 MEPC.162(56)

G8 Guidelines for Approval of BW 

Management Systems 

 MEPC.125(53)

 Rev. MEPC.174(58)

G9 Approval of BWM Systems that make 

use of Active Substances 

 MEPC.126(53)

 Revision MEPC.169(57)

G10 Approval and Oversight of Prototype 

BW Treatment Programs

 MEPC.140(54)

G11 Guidelines for BW Exchange Design 

and Construction Standard

 MEPC.149(55)

G12 Design and Construction to Facilitate 

Sediment Control on Ships

 MEPC.150(55)

G13 Guidelines for Additional Measures 

Regarding BWM Including Emergency 

Situations 

 MEPC161(56) 

G14 Guidelines on Designation of Areas for BWE

 MEPC.151(55)

Note: BW = Ballast Water

 BWM = Ballast Water Management

 BWE = Ballast Water Exchange

Of special interest to owners and builders are the 

requirements for ballast water sampling contained 

in the G2 guideline as it impacts ballast system 

design and operation. The objective of the G2 

guideline is to provide all parties, including Port 

State Control offi cers, with practical and technical 

guidance on ballast water sampling and analysis for 

determining if the ship is in compliance with the 

Ballast Water Management Convention. 

It is important to note that the G2 guideline 

discusses general sampling procedures and does 

not address the legal requirements as the legislative 

procedures and requirements for enforcement 

action based on biological testing are signifi cantly 

different from country to country. The guideline 

includes the following issues related to operation of 

the treatment system:

• It was recognized by IMO that the sampling must 

be simple, rapid and applicable at the point of 

ballast discharge and safe to the ship and crew. 

Time needed for the analysis of the collected 

samples shall not be used as a basis for unduly 

delaying the operation, departure or movement 

of the vessel.

• The sample is to be taken from the discharge 

line, as near to the point of discharge as possible, 

during discharge. Note that the G8 guideline also 

calls for sampling points; however, the points in 

the G2 guideline are not just for testing during 

the type approval but also for in-service testing. 

Tank sampling for those systems which use a 

treatment system is not preferred as the scientifi c 

trials have shown that these samples may not 

provide accurate estimates of the organism 

concentration. An exception to this guidance 

may be when the ballast tanks are emptied 

through direct overboard discharge valves such 

as in upper wing tanks.

• Isokinetic sampling ports are recommended so 

that the sample water is collected at the same 

fl ow rate as the ballast water in the discharge 

line, since this will lessen the likelihood of there 

being a difference in the organism and particulate 

matter concentrations.

• Initial and indicative analysis to establish 

whether a ship is complying with the D-2 

standard may be undertaken and, if further 

doubt exists, the samples are to undergo a more 

stringent analysis to establish if the D-2 standard 

is being met.

The use of monitoring and in line recording 

devices of physical and/or chemical indicators are 
being proposed and developed as a valid means to 

verify that the ballast water is adequately treated 

and conforms to the Ballast Water Treatment 

Performance standard.

Regulation C-1 of the Convention enables a Party 

to the Convention, either individually or jointly 

with other parties, to take additional measures in 

addition to those in the Convention to prevent, 

reduce or eliminate the transfer of harmful 

organisms and pathogens. In recognizing the 

potential impact that such measures may have on 

international shipping, IMO developed the G13 

guideline. 

The provisions in this regulation and guideline are 

subject to the notifi cation of the organization or 

in some instances approval by the organization, 

allow for these additional measures. The MEPC 

may grant approval for the additional measures 

to control aquatic invasive species in a specifi ed 

region as part of its evaluation criteria. The 

MEPC determines if these additional measures 

could adversely affect areas adjacent to the region 

or impact the safety or commercial nature of 

international shipping activities. 

It is not certain how regional measures that are 

more stringent than IMO requirements would be 

viewed under this guideline. This is potentially 

very important for those vessels intending to transit 

to regions with local requirements, for example US 

waters. Guidelines G8 to G10 address the approval 

of ballast water treatment systems. 

Overview of Some Regional,

National & Local Regulations

United States/USCG

The United States fi rst passed ballast water 

legislation in 1990 as the Nonindigenous Aquatic 

Nuisance Prevention and Control Act of 1990 

(NANPCA). This law established the US Coast 

Guard’s (USCG) regulatory jurisdiction over ballast 

water management, mandated a regional ballast 

water management program for the Great Lakes 

and called for studies to document the need for a 

national ballast water management program. 

To implement the NANPCA the USCG published 

a fi nal rule in the Federal Register on 8 April 

ABS BALLAST WATER TREATMENT ADVISORY • 7
8 • ABS BALLAST WATER TREATMENT ADVISORY

1993 wherein 33 CFR Part 151, Subpart C, the 

mandatory ballast water management requirements 

for ships entering the waters of the Great Lakes 

after operating outside of the US Exclusive 

Economic Zone were established. These regulations 

were extended to portions of the Hudson River 

in 1994. In 1996, the US Congress enacted the 

National Invasive Species Act (NISA). This charged 

the USCG with establishing a voluntary ballast 

water management program for all other US 

ports and required vessels to submit ballast water 

management reports. 

In addition, this Act directed the USCG to 

submit a report to the US Congress on the 

effectiveness of the voluntary program and 

to make the program mandatory if the rate of 

compliance with the voluntary guidelines was 

determined to be inadequate. In May 1999 the 

USCG published an interim rule in the Federal 

Register entitled “Implementation of the National 

Invasive Species Act of 1996”. This interim rule 

created the mandatory ballast water reporting 

and recordkeeping requirements and prompted 

voluntary BWM practices (including ballast water 

exchange) for all vessels entering all waters of the 

United States after operating outside the exclusive 

economic zone. 

In November 2001, the interim rule was amended 

and published as a fi nal rule. On 3 June 2002, the 

USCG submitted the fi rst ballast water management 

report to Congress wherein it was concluded 

that compliance with the mandatory reporting 

requirements was insuffi cient to allow for an 

accurate assessment of the voluntary ballast water 

management program. This report to Congress 

also stated that it is the intention of the Secretary 

of Homeland Security to have the USCG take 

additional actions to reduce the infl ow of aquatic 

nuisance species. In June 2004, the voluntary 

guidelines of 33 CFR 151, Subpart D were made 

mandatory for all vessels equipped with ballast 

water tanks. 

There have been a number of bills introduced in 

the US Congress that propose a ballast discharge 

standard. None have yet become law. However, the 

USCG released a notice of proposed rulemaking 

(FR 44633 28 August 2009). The proposed 

rulemaking and regulatory analysis includes an 

assessment of the economic impact of treatment 

standards between the IMO D-2 levels and levels up 

to 1,000 times more stringent (see Table 3). 

The proposed treatment regulation calls for a 

two-phase implementation schedule. The Phase 

1 standard is the same as the IMO D-2 and the 

implementation schedule is similar to the IMO 

schedule. Existing ships (those built prior to 

1 January 2012) with ballast water capacity of 

between 1,500 and 5,000 m3

 will be required to 

meet this standard by their fi rst drydocking after 

1 January 2014. Ships with ballast water capacity 

of less than 1,500 m3

 or greater than 5,000 m3 must 

meet the standard by their fi rst drydocking after 1 

January 2016. New vessels (those with build dates 

on or after 1 January 2012) will be required to meet 

it at delivery. 

Phase 2 discharge requirements must be met by 

new ships with a build date on or after 1 January 

2016. For ships with a build date before 1 January 

2016, the compliance date is the fi rst drydocking 

Table 3: Discharge Standards in USCG Proposed Regulation (August 2009)

Organism Size US Proposed Regulation 

Phase 1 Standard

US Proposed Regulation 

Phase 2 Standard IMO Regulation D-2

> 50μm in min dimension < 10 viable organisms/m3 < 1 viable organisms/100m3 < 10 viable organisms/m3

< 50μ and >10μ in min. 

dimension < 10 viable organisms/ml < 1 viable organisms/100ml < 10 viable organisms/ml

< 10μm in min. dimension no limit < 103

 bacteria/100 ml

< 104 viruses/100 ml no limit

Escherichia coli < 250 cfu/100 ml < 126 cfu/100 ml < 250 cfu/100 ml

Intestinal enterococci < 100 cfu/100 ml < 33 cfu/100 ml < 100 cfu/100 ml

Toxicogenic Vibrio cholerae < 1 cfu/100 ml < 1 cfu/100 ml 

< 1 cfu/100 ml or 

< 1 cfu/gram wet weight 

zooplankton samples
ABS BALLAST WATER TREATMENT ADVISORY • 9

Table 4: Discharge Standards in Current California Law

after 1 January 2016 or fi ve years after a Phase 1 

system was installed, whichever is later. A 

‘practicability review’ by the USCG is also proposed 

for 2013 to evaluate whether the technology to 

achieve the Phase 2 standard is available in order 

to confi rm the future phase entry into force dates. 

While the standards and schedule generally apply 

to all commercial ships discharging ballast in US 

waters, there is a notable exemption for crude oil 

tankers engaged in coastwise trade. The issuance of 

the fi nal USCG regulations originally scheduled for 

December 2010 has been delayed.

Ballast discharges in US ports are further regulated 

by the Vessel General Permit (VGP) for the 

National Pollution Discharge Elimination System 

(NPDES) program under the Clean Water Act 

(CWA). Previously exempted from the NPDES 

program, ballast water discharges in port must 

now be documented and the vessel must follow 

federal regulation aimed at controlling discharge 

of harmful or invasive elements within the ballast 

water. Treatment is not explicitly required and 

there is no treatment standard in US Federal 

regulatory regime in the current VGP. However, the 

CWA allows each individual State to add specifi c 

provisions, including performance standards, to the 

VGP. A treatment system that uses active substances 

(chemicals or biological agents) would be subject 

to scrutiny under the Clean Water Act. 

California

California’s Marine Invasive Species Act (2003) 

established the Marine Invasive Species Program 

and directed a state agency to develop performance 

standards for ballast water discharge. In 2006, the 

State passed the Coastal Ecosystems Protection Act 

(SB497) which incorporated the recommended 

standards and made them mandatory. The 

implementation schedule was initially set to match 

the IMO schedule. In 2008, a review required 

by the law of available treatment technologies 

recommended that the implementation date for 

new ships be delayed one year to 2010.

As shown in Table 4, the California standards are 

much more stringent than the IMO standards and 

similar (but not identical) to the Phase 2 standard 

recently proposed by the USCG (shown in Table 

3). The California law includes explicit guidelines 

for sampling points and methods. In addition, 

California law currently sets a fi nal discharge 

implementation date of 1 January 2020 that 

specifi es zero detectable living organisms for all size 

ranges in the ballast discharge stream.

Other US States

Michigan, Minnesota and Wisconsin have specifi c 

state laws and regulations establishing ballast water 

discharge standards or management programs. In 

addition, a number of other US states have included 

ballast water discharge standards as part of their 

Clean Water Act certifi cation with the VGP. 

In February 2011, the state of New York’s Water 

Quality Certifi cation Agency issued a letter 

granting an extension of the implementation 

date for ‘Condition 2’ (which is 100 times more 

stringent then the IMO’s D-2 Regulation) from 

1 January 2012 until midnight 13 August 2013. 

Organism Size California Law IMO Regulation D-2 US Proposed Law 

Phase 2 Standard

> 50μm in min. dimension No detectable living organisms < 10 viable organisms/m3 < 1 viable organisms/100 m3

< 50μ and > 10μ in min. 

dimension < 0.01 living organisms per ml < 10 viable organisms/ml < 1 viable organisms/100 ml 

< 10μm in min. dimension < 103

 bacteria/100 ml

< 104

 viruses/100 ml no limit < 103

 bacteria/100 ml

< 104

 viruses/100 ml

Escherichia coli < 126 cfu/100 ml < 250 cfu/100 ml < 126 cfu/100 ml 

Intestinal enterococci < 33 cfu/100 ml < 100 cfu/100 ml < 33 cfu/100 ml 

Toxicogenic Vibrio cholerae

< 1 cfu/100 ml or 

< 1cfu/gram wet weight 

zoological samples 

< 1 cfu/100 ml or 

< 1 cfu/gram wet weight 

zooplankton samples

< 1 cfu/100 ml 
10 • ABS BALLAST WATER TREATMENT ADVISORY

Section 2

BWT Technologies

This section of the Advisory Notice provides an 

explanation of treatment technologies currently 

being developed, the regulatory approval process 

certifying vendor-supplied equipment as compliant 

with the regulation, and a list of available systems 

currently on the market as of the date of publication 

of this document. 

Overview of Treatment 

Technologies

IMO defi nes ballast water treatment equipment as:

“...the equipment which mechanically, 

physically, chemically or biologically processes 

either singularly or in combination to remove, 

render harmless or avoid the uptake or 

discharge of harmful organisms or pathogens. 

Ballast water treatment equipment may operate 

at the uptake or discharge of ballast water, 

during the voyage, or at a combination of 

these events.”

Types of Treatment Technologies

The technologies currently available or being 

developed can generally be grouped under three 

broad categories based on their primary mechanism 

for rendering the organism inactive: mechanical, 

physical and chemical. These groups and the more 

promising technologies related to each are shown in 

Figure 1 and described briefl y in the following text.

Mechanical Systems

• Filtration – sediment and particles are removed 

with disk and screen fi lters during ballast intake. 

They are often self-cleaning with a back-fl ushing 

cycle. The waste stream is directed overboard 

back to the water source. These fi ltration systems 

create pressure drops and a reduced fl ow rate due 

to resistance in the fi lter elements and the selfcleaning procedures.

• Cyclonic separation – solid particles are 

separated from the water due to centrifugal 

forces. Only those particles with a specifi c gravity 

greater than that of water can be separated.

• Electro-mechanical separation – a fl occulent is 

injected that attaches to organisms and sediment. 

Magnetic separation and fi ltration is used to 

remove the solid particles.

Physical Disinfection

• Ultraviolet light – UV radiation is used to 

attack and break down the cell membrane 

killing the organism outright or destroying its 

ability to reproduce. The effectiveness depends 

on the turbidity of the ballast water (i.e. the 

concentration of sediments) as this could 

limit the transmission of the UV radiation. UV 

lights are required to be maintained and power 

consumption needs to be considered.

• Cavitation/ultrasounds – venturi pipes or slit 

plates are used to generate cavitation bubbles and 

this high energy bubble creation and collapse 

results in hydrodynamic forces and ultrasonic 

oscillations, or high frequency noise, which 

disrupts the cell walls of organisms effectively 

killing them.

Figure 1: Treatment Technology Types

Mechanical Systems Physical Disinfection Chemical Treatment

Electro-mechanical 

Separation

De-oxygenation

Filtration Ultraviolet Light / ultrasounds Disinfecting Biocides

Cyclonic Separation Cavitation Electrolytic Chlorination
ABS BALLAST WATER TREATMENT ADVISORY • 11

• De-oxygenation – 

various methods are 

used to remove the 

dissolved oxygen 

in the ballast water 

and replace it with 

inactive gases, such 

as nitrogen or other 

inert gas. Removing 

the oxygen not only 

kills the aerobic organisms but it can also have 

benefi ts for corrosion prevention provided that 

the oxygen content is maintained at the correct 

levels. De-oxygenation can require a prolonged 

period in order to render the organisms and 

pathogens harmless to the receiving waters.

Chemical Treatment

• Disinfecting biocides – pre-prepared or 

packaged disinfectants designed to be 

dosed into the ballast fl ow and kill the 

living organisms by chemical poisoning or 

oxidation. Typical biocides include chlorine, 

chloride ions, chlorine dioxide, sodium 

hypochlorite and ozone. Residual biocides in 

the ballast water must meet ballast discharge 

standards which may require neutralization 

techniques.

• Electrolytic chlorination – electrical current is 

applied directly to the ballast water fl ow in an 

electrolytic chamber, generating free chlorine, 

sodium hypochlorite and hydroxyl radicals, 

causing electrochemical oxidation through the 

creation of ozone and hydrogen peroxide. This 

method is limited in effectiveness to seawater 

having a certain level of dissolved salt and 

could also create unwanted residuals.

Types of chemical treatments include Active 

Substances or Preparations. The offi cial defi nitions given in the BWM Convention are as follows:

• Active substance – a substance or organism, 

including a virus or a fungus that has a general 

or specifi c action on or against harmful aquatic 

organisms and pathogens. 

• Preparation – any commercial formulation 

containing one or more active substances including any additives. This term also includes 

any active substances generated on board for 

the purpose of ballast water treatment and any 

relevant chemicals formed in the ballast water 

treatment system that make use of active substances to comply with the BWM Convention.

Technical Challenges & System Combinations

The treatment technologies differ in method 

and rate of application, scalability, holding time 

(required for kill rates and safe discharge), power 

requirements, effects on other ship systems or 

structure (corrosion), inherent safety and costs 

of operation. In many cases their effi cacy varies 

with the conditions of the ballast water, fl ow rates, 

volume of water treated and holding time. There 

are also issues of whether treatment is done at 

intake, while being held on board, at discharge, or 

a combination of the three. 

For instance, fi ltration, separation and UV 

radiation are done during ballast. UV radiation is 

also used during deballasting. These systems are 

sized for the maximum fl ow rate in the ballast 

system. Conversely chemical biocides and deoxygenation are usually applied to attain a certain 

concentration in the water in the ballast tanks. 

The effi cacies of these systems do not depend so 

much on the fl ow rate of the pumps as the time 

the ballast is allowed to remain in the tanks to 

achieve the desired kill rate. Short voyages can be 

a problem for these technologies. 

Matching the treatment technology to the ship 

type, or more accurately the ballast system 

type, and vessel service is the key to designing 

a successful ballast water treatment system. 

To overcome the limitations of a particular 

technology many proposed treatment systems 

are based on a combination of two or more 

technologies. Although there are approved 

chemical disinfection only treatments, these are 

often combined with some form of pre-treatment 

to make them more effective for certain vessel or 

ballast conditions. 

The most prevalent system types are ones that 

combine mechanical separation/fi ltration with 

UV radiation or chemical disinfection. The initial 

mechanical separation/fi ltration is used to remove 

the larger organisms in order to increase the 

effectiveness of the secondary treatments.
Treatment System Approval 

by IMO & Member States

IMO Approval Regime

Regulation D-3 of the BWM Convention requires 

that ballast water treatment systems be approved 

by the fl ag State Administration and for those 

treatment systems which make use of active 

substances or preparations, by the IMO as well. It is 

important to note that the Convention requires that 

discharges of ballast water from ships must meet 

the D-2 standard on an ongoing basis. 

Type approval of a ballast water treatment system 

should not be considered as an indication that a 

given system will work on all vessels in all situations. Even after installing a type approved system, 

the owner/operator is still responsible for compliance of the discharge throughout the vessel’s life. 

To achieve consistency in the approval process, 

IMO has prepared several guidelines. 

G8 Guidelines for Approval of Ballast Water 

Management Systems 

 Resolution MEPC.174(58)

G9 Procedure for Approval of Ballast 

Water Management Systems that 

Make Use of Active Substances 

 Resolution MEPC.169(57)

G10 Guidelines for Approval and Oversight 

of Prototype Ballast Water Treatment 

Technology Programs 

 Draft Resolution MEPC.140(54)

These guidelines outline the approval framework 

and a uniform manner of testing, analysis of 

samples and evaluation of results. Together, 

the G8 and G9 guidelines address the approval 

required under Regulation D-3 of the Convention 

for those ballast water treatment systems that 

make use of active substances. G8 addresses the 

suitability and effi cacy of the system. In addition, 

where it can be reasonably concluded that the 

treatment process could result in changes to the 

chemical composition of the treated water such 

that adverse impacts to the receiving waters might 

occur upon discharge, additional testing will 

be required by the G8 guideline. G9 addresses 

the acceptability of any active substances and 

preparations for use in ballast water treatment 

systems concerning ship safety, human health 

and the aquatic environment. The G9 guideline 

is provided as a safeguard for the sustainable use 

of active substances and preparations. 

To encourage the development of new ballast 

water treatment technologies, the Convention 

includes an allowance for short term approval 

of a treatment system that undergoes prototype 

testing according to G10 guideline. For any ship 

12 • ABS BALLAST WATER TREATMENT ADVISORY
ABS BALLAST WATER TREATMENT ADVISORY • 13

that participates in a prototype testing program, 

the requirements of Regulation D-2 shall not 

apply until fi ve years after the date the equipment 

was installed or fi ve years after the date on which 

the ship would otherwise be required to comply 

with D-2, whichever is later.

The G8/G9 approval process is a robust and 

lengthy process requiring approximately one year 

to complete. It includes the following:

• Documentation review and approval of the 

design and construction of the system and 

an assessment to determine if there are any 

fundamental problems that might constrain the 

ability of the system to manage ballast water or 

operate safely. 

• Successful compliance with environmental 

testing by an approved laboratory of all system 

components. This testing is to include specifi ed 

limits of vibration, temperature, humidity, 

fl uctuations in power supply, inclination and, 

if applicable, protection from green water 

impact.

• Land-based testing to confi rm that the system 

can meet the D-2 standard for a range of 

water conditions (fresh, brackish and sea). 

The land-based approval testing is intended 

to provide replicability and comparability 

to other treatment systems. Any limitations 

imposed by the treatment system on the testing 

procedure should be noted and evaluated by 

the Administration in its consideration for 

type approval. In some situations, the landbased testing can be done on scaled-down 

equipment. 

• Shipboard testing of a complete, full scale 

system throughout a full ballast cycle (uptake, 

storage, treatment, and discharge). At least 

three consecutive successful test cycles that 

comply with Regulation D-2 are required over 

a period not less than six months.

Systems with active substances or preparations 

must undergo the additional approval process 

contained in the IMO G9 guideline to verify that 

the potential hazardous properties of the active 

substance or preparations or relevant chemicals 

formed in treated ballast water do not create any 

unreasonable risk to the ship and personnel and 

that the ballast water is no longer toxic. Toxicity 

testing is needed to confi rm that the active 

substance or preparation used does not cause 

conditions which have the potential of harming 

the receiving environment or human health.

The additional approval required under the G9 

guideline uses a two-tier methodology consisting 

of a basic and fi nal approval.

• Basic approval confi rms that, based on the 

information available, there are no unacceptable 

adverse effects, nor a potential for unreasonable 

risk to the environment, human health, property 

or resources. It includes screening for 

persistency, bioaccumulation and toxicity. 

Testing is conducted in a laboratory under 

conditions simulating ballast water discharge 

following treatment.

• Final approval confi rms the previous evaluations 

of risks to the ship, crew and the environment 

including the storage, handling and application 

of active substances or preparations, remain 

valid and concerns expressed during the basic 

approval process have been addressed, as well as 

the residual toxicity of the discharge conforms 

to the evaluation undertaken for basic approval. 

In addition, a risk evaluation is performed at 

the fi nal approval to qualitatively account for 

the cumulative effects that may occur due to the 

nature of shipping and port operations.

Both steps involve not only review by the 

Administration, but are also subject to a direct and 

complete review by a special technical group set 

up within IMO. This technical group is the Group 

of Experts on the Scientifi c Aspects of Marine 

Environmental Protection – Ballast Water Working 

Group (GESAMP-BWWG). The GESAMP-BWWG 
Once the technical review and testing are completed to the satisfaction of the Administration 

and the Administration is satisfi ed that the quality 

assurance program employed by the manufacturer 

will mean that the equipment can be produced 

consistently to the required specifi cation, a Type 

Approval Certifi cate may be issued. When a type 

approved ballast water treatment system is installed on board a vessel, an installation survey 

is conducted to confi rm that the system has been 

installed as designed, is ready for 

operation, and conforms to the Type 

Approval Certifi cate. Upon successful 

completion of the installation survey, 

a BWM Certifi cate may be issued as 

required by the Convention.

Verifying Equipment Approval

Any system which is being considered 

for installation on board a ship should 

have a valid Type Approval Certifi cate 

in the proper form and signed by 

the Administration. This certifi cate 

should: 

• Identify the type and model of 

the system, related equipment 

assembly drawings and model 

specifi cation numbers;

• Include a reference to the full 

performance test protocol on 

which the approval is based and 

be accompanied by a copy of the 

original test results;

• State the specifi c application for 

which the treatment system is 

approved, e.g. for specifi c ballast 

water capacities, fl ow rates, 

salinity or temperature regimes, 

or other limiting conditions or 

circumstances as appropriate.

makes a recommendation to the IMO MEPC which, 

on the basis of the GESAMP-BWWG’s report, will 

confer approval on a treatment system that uses 

active substances. 

The overall approval process is summarized in 

Table 5. Shaded parts (G9) can be omitted for 

systems not using active substances (e.g., deoxygenation or ultrasonic). A more complete fl ow 

chart of the approval process is shown in Figure 2.

Table 5: Ballast Water Treatment System Approval Process Overview

Approval Process for Manufacturer Ship-Specifi c 

Approval

Key Steps in 

Approval Process

Documentation 

Review 

& Approval

Basic Approval 

for Active 

Substances 

(G9)

System 

Approval Land 

& Shipboard 

Testing

Final Approval 

for Active 

Substances 

(G9)

Type Approval 

Certifi cate

Installation 

Survey

Approval 

Authority Administration GESAMPBWWG, IMO Administration GESAMPBWWG, IMO Administration Administration

14 • ABS BALLAST WATER TREATMENT ADVISORY
ABS BALLAST WATER TREATMENT ADVISORY • 15

Figure 2: Flow Chart of Ballast Water Management System Approval 

BWM System

(treatment, control & monitoring)

Yes

Yes

No

Yes

Yes

Yes

Yes

No

No No

G(9)

G(9)

G(8)

Type

Approval

Prototype

Testing G(10)

Yes

Yes

No

Yes No

Results may 

be used

No

No

No

Yes

Yes

No

No

Manufacturer tests 

found satisfactory 

by a government

BWMS includes active 

substances

Basic approval or 

active substances 

granted by IMO

Land-based testing 

to D-2 standard 

is satisfactory

Shipboard testing 

to D-2 standard 

is satisfactory

BWMS includes 

active substances

BWMS adversely changes 

chemical composition 

of treated water

Shipboard testing 

to evaluate against 

D-2 standard

All BW discharged 

during test period 

meets D-2 standard

Ship issued BWM 

Certifi cate after functional 

test of BWMS

Documentation review & approval by a government

BMW system test 

protocol options

Final approval for 

active substances 

granted by IMO

Government grants 

type approval 

of BWMS

Type Approved BWMS 

can be installed on board 

any ship
16 • ABS BALLAST WATER TREATMENT ADVISORY

System Name Proposed By Approval Type Approved By

PureBallast System Norway Basic & Final MEPC 56

SEDNA-Ocean BWM System using PERACLEAN Ocean System Germany Basic / Final MEPC 54 / MEPC 57

OceanSaver BWM System Norway Basic / Final MEPC 57 / MEPC 58

Electro-Cleen System (Electrolytic Disinfection) Korea Basic / Final MEPC 54 / MEPC 58

RWO BWMS (CleanBallast) Germany Basic / Final MEPC 55 / MEPC 59

NK-03 Blue Ballast System (Ozone) Korea Basic / Final MEPC 56 / MEPC 59

Hitachi BW Purifi cation System (ClearBallast) Japan Basic / Final MEPC 57 / MEPC 59

Hamworthy Sedinox BWMS Netherlands Basic / Final MEPC 58 / MEPC 59

Resource Ballast Technologies System (Unitor) South Africa Basic / Final MEPC 57 / MEPC 60

GloEn-Patrol System Korea Basic / Final MEPC 57 / MEPC 60

JFE BallastAce (in cooperation with TG) Japan Basic / Final MEPC 58 / MEPC 60

HHI BWMS (EcoBallast) Republic of Korea Basic / Final MEPC 59 / MEPC 60

FineBallast OZ Japan Basic / Final MEPC 55 / MEPC 61

Ecochlor BW Treatment System Germany Basic / Final MEPC 58 / MEPC 61

ARA Ballast BWMS Republic of Korea Basic / Final MEPC 60 / MEPC 61

BalClor BWMS China Basic / Final MEPC 60 / MEPC 61

OceanGuard BWMS Norway Basic / Final MEPC 60 / MEPC 61

Severn Trent DeNora BWMS (BalPure) Germany Basic / Final MEPC 60 / MEPC 61

AquaTriComb BW Treatment System Germany Basic MEPC 59

Blue Ocean Shield BWMS China Basic MEPC 59

SiCURE BWMS Germany Basic MEPC 60

DESMI Ocean Guard BWMS Denmark Basic MEPC 60

HHI BWMS (HiBallast) Republic of Korea Basic MEPC 60

KS BWMS (En-Ballast) Republic of Korea Basic MEPC 60

TWECO BWMS (Purimar) Republic of Korea Basic MEPC 61

AquaStar BWMS Republic of Korea Basic MEPC 61

Kuraray BWMS Japan Basic MEPC 61

Table 6: BWM System Approvals as of MEPC 61

Approval Status of BWM Systems using Active Substances (G9)

Treatment System Approval Status

The following tables summarize the current basic, fi nal and type approval status of record. Systems that 

have received fi nal and/or type approval are described more fully in the Appendix of this Advisory. 
ABS BALLAST WATER TREATMENT ADVISORY • 17

Table 7: Ballast Water Management Systems with Type Approval Certifi cation (G8)

Approval 

Date Name of Administration Name of the Ballast Water Management System

Active Substances 

Employed

1

June 2008

March 2011

Norwegian Administration

Norwegian Administration

PureBallast System

PureBallast 2.0 & PureBallast 2.0 Ex

Free radicals Cl2-, ClB-, 

Br2- and CO3-

(Refer to MEPC 56/2/2, Annex 5)

2 June 2008

Federal Maritime & 

Hydrographic Agency, 

Germany

SEDNA® BWMS 

(Using Peraclean®

Ocean System)

(temporarily withdrawn 

from the market)

PERACLEAN® Ocean

(Refer to MEPC 57/2/10, Annex 7)

3

September 2008

January 2010

Maritime Administration, 

Marshall Islands

Merchant Shipping 

Directorate, Malta

Venturi Oxygen StrippingTM System 

(NEI) None Used

4 December 2008

Ministry of Land, 

Transport & 

Maritime Affairs, 

Republic of Korea

Electro-CleenTM System

HOCl (OCl-), HOBr (OBr-). 

O3 (H2O2), OH-

(Refer to MEPC 58/2/7, Annex 7)

5 April 2009 Norwegian Administration OceanSaver® Ballast Water 

Management System 

HClO, Cl2, O3, H2O2, ClO2 and ClO-

(Refer to MEPC 58/2/8, Annex 4)

6 April 2009 The United Kingdom

Hyde GuardianTM

Ballast Water 

Management System

None Used

7 November 2009

Ministry of Land, Transport and 

Maritime Affairs, 

Republic of Korea

NK-O3 BlueBallast System O3

(Refer to MEPC 59/2/16, Annex 6)

8 November 2009 Norwegian Administration OptiMarin Ballast System None Used

9 December 2009

Ministry of Land, Transport 

and Maritime Affairs, 

Republic of Korea

GloEn-PatrolTM MPUV Irradiation

(Refer to MEPC 60/2/11, Annex 4)

10 March 2010

Maritime Bureau, Ministry of 

Land, Infrastructure, Transport 

and Tourism of Japanese 

Government

Hitachi ClearBallastTM PAC, Fe3

O4 and PASA

(Refer to MEPC 59/2/19, Annex 4)

11 May 2010

Maritime Bureau, Ministry of 

Land, Infrastructure, Transport 

and Tourism of Japanese 

Government

JFE BallastAce System

TG Ballastcleaner 

(Main Ingredient - NaOCI)

TG Environmentalguard

(Main Ingredient - Na2

SO3)

(Refer to MEPC 60/2/12, Annex 5)

12 August 2010 Maritime Safety Authority,

South Africa

Unitor Ballast Water 

Treatment System

NaOCI and O3

(Refer to MEPC 60/2/11, Annex 7)

13 December 2010

Federal Maritime and 

Hydrographic Agency, German 

Administration (BSH)

ClearBallast (RWO)

Hydroxyl Radicals and Free Active 

Chlorine (HOCl/OCl-)

(Refer to MEPC 59/2)
Section 3

BWT Considerations

This section summarizes the practical realities 

of shipboard ballast water treatment systems to 

assist in the evaluation of treatment technology 

options and plan for their installation. Included 

are discussions of the key features of ships’ 

ballast water handling systems and practices, and 

the features of the various treatment technologies 

that will have an important impact on the ship or 

ballast practices and costs. 

Considerations for Selection 

of Treatment Systems 

Overview

Ballast water treatment remains an evolving 

technology with an ever-growing number of 

manufacturers developing systems to meet the 

anticipated regulatory requirements. Readers are 

urged to contact ABS or review the latest IMO 

information to determine the current status 

of treatment system approvals. This current 

situation means that there is limited in-service 

experience for the systems being offered and 

there is a general understanding that no single 

system is suitable for all ship types or service. 

The owner/operator must make a considered 

choice for the ballast water treatment that best 

suits the demands of the ship and service taking 

into account vendor specifi cations and the extent 

of shore side and shipboard testing carried out 

during the type approval process. A careful 

engineering analysis of the following factors 

bring order to the decision-making process. 

These issues are discussed in some detail as 

follows. 

Ship and Vessel Service Characteristics 

• Ship type and capacity

• Ballast water handling practices including 

NOBOBS (no ballast on board ships)

• Ballast water characteristics

• Vessel service characteristics

• Ballast system characteristics

Treatment Technology Factors 

• Treatment method 

• Treatment system pressure drops

• Equipment size and space requirements 

• Materials, equipment protection (IP rating) 

and hazardous spaces

• Power requirements

• Impacts on ballast tank and pipe corrosion

• Health and safety (handling, operation and 

maintenance)

General Treatment System Considerations

• Proven effi cacy and offi cial approvals

• Vendor qualifi cations and reputation

• Maintenance requirements and system 

reliability

• Simple operation (control and monitoring)

• Life cycle costs

• Serviceability and availability of spare/

replacement parts

Challenges for Installation Engineering 

• Intake/discharge isolation 

(cross-contamination)

• Sampling and in-service testing

• Maintaining ballasting fl exibility

18 • ABS BALLAST WATER TREATMENT ADVISORY
ABS BALLAST WATER TREATMENT ADVISORY • 19

Ship & Vessel Service 

Characteristics

Ship Type & Capacity

In most instances, the ship type will be the 

largest single deter-minant in selecting a suitable 

treatment system. For this purpose it is convenient 

to consider two groups of ship types: high ballast 

dependent ships such as tankers and bulkers; and 

low ballast dependent ships such as containerships, 

general cargo ships, and cruise ships. These 

groupings are based on differences in total ballast 

capacity, amount of discharge at any one port and 

ballast fl ow rates.

As the data in Table 8 indicates, there is a wide 

range of ballast capacities and pumping rates 

common to the commercial ship sector. Notably, 

the high ballast-dependent vessels regularly sail 

in ballast only conditions (without cargo). Their 

pump rates are designed to allow full load or 

discharge in a fi xed period of time to facilitate rapid 

port turnaround times (typically 12, 18 or 24 hours 

for ballast operations). The low ballast dependent 

vessels generally have smaller ballast capacities and 

also may rarely undertake a ballast only voyage. 

Their pumps do not typically have to handle a 

full load of ballast on a regular basis. Movement 

of ballast is more limited and 

often is a shift (one tank 

to another to adjust trim 

or heel) rather than a 

simple full ballast load/

discharge operation.

Ballast Water Handling 

Practices

The proper sizing of a treatment 

system depends on the amount 

of ballast that has to be treated 

at any given port, more so than 

the total ballast capacity or 

maximum fl ow rate. If, through 

active ballast management, 

discharge can be reduced or 

eliminated then treatment 

demands decrease. For example, 

most containerships rarely need 

to discharge a full ballast load at 

any one time. 

It also should be noted that a 

large amount of the treatment 

system prototype testing is done on moderately sized 

systems (< 250 m3

/hour) or is scaled up from other 

industries and not all systems scale up well to the 

sizes required for the high ballast capacity pumping 

rates or volumes of several thousand m3

/hour. 

Another ballast practice issue that impacts treatment 

selection is how accumulated mud and silt in the 

ballast tanks is addressed. This residue itself can 

contain invasive species even when the tank is 

empty of water (a NOBOB – no ballast on board 

condition). Even if ballast is loaded locally it can 

become contaminated by the residue in the tank. 

This may necessitate the treatment of ballast water 

on discharge as well as loading. If there is little mud 

accumulation and the tanks are cleaned regularly, 

this may be less of a concern and the treatment 

system can be selected accordingly. For those ships 

constructed in or after 2009, compliance with G12 

guideline is to be applied.

Ballast Water Characteristics

Turbidity, salinity and silt content can impact 

the effi cacy, maintenance or reliability of some 

technologies. If regular calls in a port are planned 

where the water has high mud/silt content or has a 

low salt content (fresh or brackish) these should be 

considered in the treatment technology selection.

Diagram of Ballast Water Management System
20 • ABS BALLAST WATER TREATMENT ADVISORY

Table 8: Ballast Water Capacity & Ballast Pump Rates by Vessel Type

Vessel Category Vessel Type Representative Ballast 

Capacity (m3

)

Representative 

Pump Rate (m3/hr)

High Ballast 

Dependent 

Vessels

Bulk Carriers

Handy 18,000 1,300

Panamax 35,000 1,800

Capesize 65,000 3,000

Tankers

Handy 6,500 1,100

Handymax-Aframax 31,000 2,500

Suezmax 54,000 3,125

VLCC 90,000 5,000

ULCC 95,000 5,800

Low Ballast 

Dependent 

Vessels

Containerships

Feeder 3,000 250

Feedermax 3,500 400

Handy 8,000 400

Subpanamax 14,000 500

Panamax 17,000 500

Postpanamax 20,000 750

Other Vessels

Chemical Carriers 11,000 600

Passenger Ships 3,000 250

General Cargo 4,500 400

Ro/Ro 8,000 400

Combination Vessels 7,000 400

Note: Representative values are nominal values that refl ect a combination of data sources and vessel sizes in each category.

Vessel Service Characteristics

The vessel service or trade route may also 

be critical for treatment system selection. 

For example, certain ship types may not be 

discharging ballast in the US so there will be 

no concern for US regulations other than the 

reporting and recordkeeping requirements. 

The key regulatory requirement and effi cacy 

standards will be those from IMO. If treatment 

options for local requirements are too expensive, 

then operators that trade in those areas only 

occasionally may opt to forego shipboard 

installation of additional treatment capability. 

Instead they may adjust their ballast management 

to avoid discharge or pay high use costs for a 

shore/port based system (where available).

Common Ballast System Characteristics

There are also a number of other vessel 

features related to ship type that are not 

exclusive to the high/low ballast dependent 

categorization defi ned above yet have an 

impact on treatment system selection. These 

include the number of separate ballast 

systems (e.g., oil tankers often have two, 

one in way of the cargo area and one aft 

of the cargo), whether eductors are used 

to supplement ballast discharge, small or 

crowded engine rooms, or explosion proof 

ballast equipment requirements. How 

these features represent design challenges 

for treatment systems are discussed in the 

following sections. 
• Mechanical systems (fi ltration or separation)

• Physical disinfection (UV radiation, cavitation, 

de-oxygenation, etc.)

• Chemical treatment (biocides and electrochlorination)

Each system has a few fundamental characteristics 

that impact its suitability for certain ship types, 

service or fl ow rates. Most of the treatment 

systems use a combination of two or more of these 

technologies to overcome an individual technology’s 

shortcomings.

Mechanical Systems

These require redirecting the full ballast fl ow 

through fi lters, hydrocyclones or other separators. 

For high volume applications, the size of the 

equipment required can be problematic. If they 

are used during ballast discharge, the fi ltrate must 

be maintained on board. High sediment loads can 

cause problems for fi lters.

Physical Disinfection

Ultraviolet radiation and cavitation require 

processing of the entire ballast fl ow but holding 

time is not required as treatment is complete 

once the water passes through the equipment. 

UV exposure is usually done at both intake and 

discharge. Its effectiveness degrades with cloudy 

or turbid water that restricts light penetration. 

Treatment Technology Factors 

The second most important set of factors in 

selecting a suitable treatment system, after ship 

type and service, are the operating characteristics 

and requirements of the individual treatment 

technologies. As noted in Section 2 of this 

Advisory, BWT Technologies, there are several type 

approved technologies that have satisfi ed the IMO 

D-2 standard and numerous technologies being 

actively researched and implemented that should 

be able to meet the IMO discharge standards. 

These technologies differ in method and rate of 

application, scalability, required holding time, 

power and related system requirements, impacts on 

corrosion and inherent safety. Each ship’s design, 

as well as an owner’s particular operating practices 

and internal risk assessments, will determine how 

important each of these factors is in the selection 

process. Taken together, these factors and how the 

treatment systems address them, indicate the level 

of analysis required for effective implementation of 

the particular treatment system. 

The following describes treatment factors that 

should be considered.

Treatment Method

The methods and technologies being considered 

for ballast water treatment can be grouped by basic 

approach as follows:

ABS BALLAST WATER TREATMENT ADVISORY • 21
22 • ABS BALLAST WATER TREATMENT ADVISORY

De-oxygenation can be done at intake to the full 

ballast fl ow or directly in the ballast tanks with 

bubblers. However, the full kill rates may take 

several days to achieve so the ballast tanks must 

also have a closed vent system and be fully inerted.

Chemical Treatment

These treatments are dosed into the existing 

ballast piping during intake or directly into the 

ballast tanks. The dosage rates must be adjusted 

to provide the desired kill rate. The chemicals are 

usually lethal within several hours of treatment so 

long holding times are not required. However, the 

chemicals must be neutralized or be allowed to 

become biologically ineffective before the ballast 

water can be considered safe for discharge.

Treatment System Pressure Drops

The treatment systems that process the full ballast 

fl ow through fi lters, separation systems or venturi’s, 

create added resistance to ballast fl ow. The pressure 

drops for such elements vary, with most systems 

claiming from less than 1 bar to about 2 bar. In 

some cases, back pressure valves may need to be 

added to the system after a separator to provide 

suffi cient backpressure for clearing out sludge 

and/or self-cleaning. If the installation requires 

signifi cant lengths of new ballast piping and 

valving then some additional pressure drops will be 

introduced that could prove signifi cant. 

The self cleaning or back-fl ushing operation will 

redirect some of the ballast fl ow directly overboard 

and reduce the fl ow rate into the tank further. Some 

hydrocyclones redirect between 5 percent to 10 

percent of the fl ow stream for sludge removal. 

The pressure drops and self cleaning process will 

impact in-service fl ow rates and system design 

pressure. For most ships it is not expected that 

ballast pumps will need to be upgraded. However, 

the actual fl ow rates of ballast delivered to the tanks 

achievable with the selected system must be used 

when evaluating ballasting times and operation of 

the treatment system. It could be that ballasting 

Table 9: Important Treatment Method Characteristics

Treatment 

Process Method of Treatment When Applied Time for Lethality

Corrosion 

Potential

Chlorine 

Generation 

Use electrolytic cell to generate chlorine and bromine 

that act as biocides. Next, sodium sulfate neutralizes 

the ballast water prior to discharge. As long as free 

chlorine exists in the tank, biocide will be active so 

dosage can be adjusted to keep biocide always active.

At uptake and 

neutralize at 

discharge

Hours

High dosage levels 

promote steel 

corrosion

Chemical 

Application

Mix proprietary chemicals with the ballast water 

in metered dosage rates at intake to kill living 

organisms. Chemicals degrade over time so 

ballast will be safe to discharge.

At uptake via eductor 24 hours

High dosage levels 

promote steel 

corrosion

Filtration & 

Radiation

Filtration of the incoming water, usually with 

self-cleaning 50 micron fi lters, in parallel with discharge 

of fi ltrate to the waters where intake takes place. 

Ballast water is exposed to a form of radiation, such as 

UV energy or other hydroxyl radical generator, 

to kill smaller organisms and bacteria.

At uptake for fi lter 

and UV and at 

discharge for UV

At treatment No effect

De-oxygenation

Mix inert gas generated on board with the ballast 

water, either by a venturi eductor or by bubbling from 

pipes in the tanks. This removes oxygen from the water 

and lowers pH, therefore killing the living organisms. 

This process requires the atmosphere in the ballast 

tank be maintained in an inert condition.

At uptake for some 

systems and in tanks 

for others

4 to 6 days Relatively less 

corrosive

Ozone 

Generation

Ozone is generated on board and acts as a biocide. 

It is applied during the ballast pumping process by 

eductor either at uptake or discharge. It can 

be combined with fi ltration or other methods 

of treatment.

At uptake for 

some systems and 

at discharge 

for others

Up to 15 hours

Limited effect as 

ozone has short 

life. If treated 

at discharge, no 

effect.
ABS BALLAST WATER TREATMENT ADVISORY • 23

with some treatment systems with high pressure 

drops and self-cleaning systems could take 20 

percent longer than ballasting without treatment.

It should also be noted that at some level of 

additional system resistance, gravity ballasting 

may no longer be feasible because the pressure 

differentials with the sea water are reduced and 

acceptable fl ow rates cannot be maintained. 

Some separation equipment simply cannot run 

without suffi cient system pressure drop. This will 

ultimately increase the total power required for 

the ballasting operation because the main pumps 

will have to be operated for a longer period. 

Equipment Size & Space Requirements

Treatment systems come in all shapes and sizes. 

The footprint requirements can vary from 1 to 

25 m2 for a system that can handle 200 m3/

hour. For a 2,000 m3/hour system the space 

requirements can be 1 to 100 m2. Systems that 

use fi ltration or require generating equipment 

for disinfection, inert gas generators for example, 

tend to increase in size with ballast fl ow rates 

more than other systems that treat with chemical 

dosing. 

Another very important space consideration is 

the ballast piping itself. If the treatment system 

requires new branch lines to be installed, this can 

sometimes have an even greater impact on the 

space requirements than the treatment equipment 

itself. In most engine rooms, the ballast piping 

is the largest pipe used. On small containerships 

with medium capacity pumps it can be over 250 

mm. In the high ballast capacity ships it can easily 

be over 500 mm diameter. It can be a challenge 

to fi nd room for tie-in points to the manifold area 

around the ballast pumps as well as space in the 

engine room to run signifi cant lengths of pipe 

to remote locations if suffi cient room for a piece 

of treatment equipment is unavailable. Systems 

that do not require redirecting main ballast fl ow 

certainly have an advantage in this case. 

In addition to the total or overall size of the 

treatment equipment, the system’s modularity may 

also impact the ease with which it can be installed 

in an existing engine room. Taking delivery of a 

system preassembled on a skid and expecting it 

to be installed in a single lift is unrealistic unless 

it is going in at new construction. To reduce 

installation costs and time, system components 

will usually be lifted and fi tted separately. So the 

ability of a system to be easily broken down into 

modules of convenient size and located in various 

areas in the engine room gives the installer many 

more options for completing the work. 

Not to be overlooked in the search for space for 

system installation is the need to provide for 

adequate access to the equipment for maintenance. 

This can include ladders and platforms, additional 

lighting, lifting eyes or crane rails, space for storage 

and handling of consumables and cleaning of 

internal components (as required). When necessary, 

space requirements for storage and handling of 

chemicals used in treatment systems should also be 

considered. This space can be outside the engine 

room and may require a specifi c fi refi ghting system, 

enhanced ventilation system, etc. Requirements 

related to the Material Safety Data Sheet (MSDS) 

are described later in this Advisory.

Materials, Equipment Protection (IP Rating) 

& Hazardous Spaces

A ballast water treatment system must meet all 

the normal requirements for shipboard materials, 

equipment protection and hazardous space safety. 

The materials used in the system components 

and the level of equipment protection (IP rating) 

provided should be reviewed at the type approval 

stage and certifi ed as to be in compliance with the 

class requirements for similar equipment installed 

in similar locations on board. One important aspect 

of this approval is a review of the materials for fi re 

rating where the reviewing authority deems the 

treatment system an ‘essential’ system. In that case, 

some plastic pipe materials may not be allowed. 

Additionally, specifi c valve materials and remote 

operation/shut downs may be required. These 

issues are not normally a concern for shipowners, 

unless they wish to specify higher grade 

materials for longer design service life and lower 

maintenance costs. 

Critical to selecting a system however, is an 

understanding of the rules and regulations 

pertaining to the equipment location, specifi cally 

the placement of electrical equipment in a 

hazardous space. Electrical equipment installed 

in an engine room does not have to meet the 

requirements to be considered intrinsically-safe 

(EX ia or EX ib rated). However, the installation of 

electrical equipment in a hazardous space (such as 

a cargo pump room on a tanker) would mandate 

that specifi c class and statutory requirements 

aimed a lowering risks associated with combining 

electrical equipment and a potentially explosive 

atmosphere be addressed.
24 • ABS BALLAST WATER TREATMENT ADVISORY

These traditional class and statutory requirements 

limit the electrical equipment that can be installed 

in a cargo pump room to intrinsically-safe 

equipment including certifi ed lighting fi xtures, 

a fi re extinguishing system alarm, general alarm 

and communication equipment and a throughrun of cables in extra heavy pipe. The placement 

of ballast water treatment systems in a pump room, 

on board a tanker constructed in accordance with 

these rules and regulations, that requires electrical 

power such as UV lamp banks or a current of more 

than 20 milli-amps, would not appear to be in 

compliance.

The application of the international standard IEC 

60092-502 entitled “Electrical Installations in 

Ships – Part 502: Tankers – Special Features” as 

referenced by SOLAS Regulation II-1/45.11 for 

ships constructed on or after 1 January 2007, is 

in general less restrictive on the certifi cation of 

electrical equipment than traditional class Rules. 

The installation of a ballast water treatment 

system in a pump room may be possible on 

tankers constructed on or after 1 January 2007 

provided the tanker is operated and maintained 

in accordance with the IEC standard. Such an 

installation would be contingent on compliance 

with the requirements contained in IEC 60092-

502; the submission of a detailed risk assessment 

addressing those aspects not covered in the IEC 

standard; and the approval of the designated 

approving authority.

Tanker owners and operators are also reminded 

that ballast water from tanks adjacent to cargo oil 

tanks cannot pass through or be treated by a ballast 

water system located in the engine room.

Power Requirements

Electrical power consumption by ballast water 

treatment systems is potentially a signifi cant 

hurdle for some technologies on the high ballast 

dependent ships. Large power consumers such as 

UV light banks, electrolytic chlorination systems 

and de-oxygenation systems can require 150 to 

over 200 kW for a 2,000/m3

 treatment fl ow rate. 

If these systems must operate when other large 

shipboard consumers are also operating, total 

ship service electrical generating capacity may be 

insuffi cient. 

The large electrical loads are also the main 

operating cost for these systems. In contrast, 

treatment systems that rely on chemical biocides 

and preparations that can be dosed into the ballast 

fl ow have an almost insignifi cant electrical load 

impact but require storage space, handling and 

dispensing equipment.
Impacts on Ballast Tank & Pipe Corrosion

For all ships, but especially the high ballast 

dependent ships, the battle against steel wastage 

due to salt water-induced corrosion can be the 

single largest maintenance cost as the vessel ages. 

Treatment systems that change the chemical 

composition of the ballast water and/or the 

atmosphere in the ballast tanks can impact the 

corrosion rates in the tanks and piping. If not 

designed and handled properly, treatment systems 

may also damage ballast tank coatings resulting 

in increased coating maintenance and ultimately 

increased corrosion as well. 

Systems that remove oxygen and maintain an inert, 

oxygen-deprived condition in the tanks can offer 

signifi cant reductions in corrosion rates. Some 

of the change in oxidation rate is attributable to 

changes in pH caused by the treatment. Some 

vendor studies have actually concluded that savings 

on steel and coating renewals over the life of the 

vessel are much greater than the life cycle costs 

of the treatment systems. Alternatively, many of 

the chemical biocides and preparations, including 

ozone, have been linked to increased corrosion 

rates. 

Experimental data is not always conclusive 

regarding the impact of chemical disinfectants in 

actual service conditions in ships’ ballast tanks with 

standard tank coatings and anodes, normal cycling 

of ballast levels and chemical concentrations 

required for treatment. Even de-oxygenation 

systems can cause accelerated corrosion if 

they completely remove the oxygen and create 

a condition that promotes anaerobic-type, 

microbiologically-infl uenced corrosion. This could 

be in the form of acid-producing bacteria (APB) 

and sulfate-reducing bacteria (SRB). The condition 

may be accentuated if there is an alternating 

oxygenated/de-oxygenated condition. In order 

for de-oxygenation to be benefi cial for corrosion 

protection, it has to reduce the oxygen levels 

suffi ciently to slow oxidation and kill any biofi lms 

that might form, but not so low as to provide an 

atmosphere conducive to the growth 

of APBs and SRBs. 

With the current available data, it is diffi cult 

to predict how different treatment systems will 

change corrosion rates. At this point, it is necessary 

to move forward with an understanding of this 

uncertainty and plan maintenance and inspection 

intervals to suit expected risks appropriately. 

Coating manufacturers should also be consulted 

regarding the reaction of their coatings to the 

planned additives. Only when suffi cient operational 

experience is gained with given treatment systems 

will clearer guidelines be possible. 

Health & Safety (Handling, Operation 

& Maintenance)

The use of chemical biocides and other active 

substances on board ships raises a concern over the 

health and safety of those responsible for operating 

the equipment and handling the materials, as 

well as the risk of unintentional discharge into 

the environment. Treatment systems that use 

active substances or preparations must undergo 

ABS BALLAST WATER TREATMENT ADVISORY • 25
26 • ABS BALLAST WATER TREATMENT ADVISORY

a strict review and approval process to identify 

persistence, bioaccumulation and toxicity. If 

the system is given fi nal approval by IMO, this 

indicates that persistence, bio-accumulation and 

toxicity are below threshold levels and that, if 

the substances are handled as directed, they are 

considered acceptble for shipboard use. 

Every system using active substances should 

be provided with a Material Safety Data Sheet 

(MSDS) which describes the proper storage and 

handling procedures as well as the information 

on the quantity to be added to the ballast water 

and the maximum allowable concentration of the 

substances in the treated water. 

It is important to note that limits for the level of 

active biocides that may remain in the discharged 

ballast can also be regulated by local water quality 

regulations and can vary by port. If discharging 

in sensitive areas, a treatment system with 

diffi cult to control biocide inactivation might 

not be the right choice. At the very least, the 

manufacturer should be requested to provide 

written confi rmation that the effl uent meets the 

requirements within the local jurisdictions that 

the vessel is likely to operate in. 

Compliance with the applicable IMO guidelines 

should indicate that all reasonable precautions 

have been taken to protect the health and safety 

of the crew and environment. Nevertheless, 

it does put an added hazardous material 

management burden on the crew. The skill and 

training of the crew and their ability to manage 

this safety risk should be considered when 

selecting a treatment system. 

General Treatment System 

Considerations

All ballast water treatment technologies share 

certain common selection criteria that should be 

considered in addition to the ship and technology 

specifi c factors. 

Proven Effi cacy & Offi cial Approvals

First and foremost, a system must meet the 

discharge standard applicable to the vessel’s 

voyage where ballast discharges are planned or 

likely. General worldwide service is covered by 

the IMO Convention’s requirements but some 

local authorities, such as the state of California, 

have more stringent requirements and earlier 

implementation dates. A certifi cate of type 

approval from a fl ag Administration would 

indicate that, under test conditions, the system 

meets the discharge standards required. Unless 

the installation is part of a prototype or type 

approval test, the equipment supplier should 

be able to produce the type approval certifi cate. 

Systems with type approval are also listed on 

the IMO website. This formal approval of the 
equipment will be necessary if the vessel is 

to obtain the IMO Ballast Water Management 

Certifi cate showing compliance with the 

BWM Convention following successful system 

functional tests on board. 

Vendor Qualifi cations & Reputation

As with any piece of equipment, the ability 

of the vendor or manufacturer to deliver the 

product on time and in the quantities requested 

is very important. However with this emerging 

technology, the production capacity is unproven 

and still very small in most cases. Some 

manufacturers may suffer from long lead times 

on orders, especially if demand increases rapidly. 

Even though production facilities are subject 

to quality control review by the type approval 

authority, until a track record is established, 

manufacturing quality and reliability can be an 

unknown. Those systems relying on existing 

technologies or marine components will have an 

advantage in this regard. 

Maintenance Requirements & System 

Reliability

There is insuffi cient experience with treatment 

system options to establish a good baseline for 

system reliability. Those systems relying on 

existing technologies or marine components will 

be able to provide better reliability estimates. 

Lacking in-service experience, an indication of 

reliability risk may be available by considering the 

system complexity. Filters, UV light chambers and 

simple chemical dosing systems are among the 

least complex options and regular maintenance 

is possible with ship’s crew. Electrochlorination 

and other chemical generating systems as well as 

systems with more than two stages of treatment 

can be considered among the most complex. 

Simple Operation: Control & Monitoring

All treatment systems should provide a simple 

to use remote control panel at or near the main 

ballast control panel. It should include indicator 

lights for key valves and system operations and 

an on/off control. Most systems will provide 

main control panels near the equipment that 

allow local operation but also monitor system 

operation. Beyond this, it is up to the owner how 

far integration of the treatment system is carried 

in the main control/alarm/monitoring system. If 

full integration is required, additional tie-ins with 

system electronics may need to be special ordered 

from the manufacturer.

Life Cycle Costs

The bottom line concern for owners is the 

true life cycle cost of the system. Acquisition 

costs are the most straightforward to 

determine because they are directly quoted by 

the vendors and include all their sunk costs 

for research and development, approvals and 

certifi cation. Installation costs vary from 

system to system and are more diffi cult to 

quantify. Installation costs include changes 

to existing piping, equipment and structure, 

as well as the direct equipment installation, 

connection, startup, testing and survey by the 

approval authority. Most systems will require 

some out of service time for the ship in order 

to complete the installation but none of those 

currently on the market is likely to require 

drydocking. 

Establishing both installation and operating 

costs is diffi cult as both will vary signifi cantly 

depending upon the type and size of ship, 

the system selected and prevailing market 

conditions. When evaluating the probable 

operating costs of a system, the following 

should be taken into account:

• Energy required to operate the system 

including electric power and fuel for 

generating treatment materials (ozone, 

inert gas and other biocides)

• Consumables such as chemicals, lamps 

and fi lter elements 

• Crew labor to operate and maintain the 

system, including training

Serviceability & Availability of Spare/

Replacement Parts

As noted in the Annex to Resolution 

MEPC.174(58), “Guidelines for approval 

of ballast water management systems 

(G8),” all working parts of the ballast water 

management system that are susceptible to 

wear or damage should be easily accessible 

for maintenance. Accordingly, owners and 

operators are to install the system in such 

a manner so the ship’s crew can perform 

routine maintenance which may include 

the replacement of fi lters, UV lights or 

other consumables in an effi cient manner. 

In addition, owners and operators are 

encouraged to confi rm the availability 

of spare or replacement parts and repair 

technicians on a worldwide basis.

ABS BALLAST WATER TREATMENT ADVISORY • 27
28 • ABS BALLAST WATER TREATMENT ADVISORY

Challenges for Installation 

Engineering

Many of the challenges related to engineering the 

actual installation of a ballast water treatment 

system are addressed in the section describing the 

treatment technology factors. These challenges can 

be especially acute when installing a system on 

an existing vessel. Finding solutions to treatment 

system back pressure and potential fl ow rate 

reductions, power consumption demands, control 

system integration and space requirements, as a 

well as access for installation, can be diffi cult and 

costly. 

As these are worked out with the vendor, design 

engineer and class the following additional factors 

should also be taken into consideration.

Intake/Discharge Isolation: 

Cross-Contamination

When designing the piping system modifi cation 

required for treatment system installation, care 

is required to prevent any accidental crosscontamination of intake and discharge water. 

This is a concern for systems that redirect the 

main ballast fl ow. Cross-contamination can occur 

if contaminated water, either from the sea chest 

or a tank which may require treatment prior to 

discharge, passes through a pipe that is shared by 

the treated ballast water being discharged. Valves 

which do not provide a reliable seal may also allow 

some contamination of treated ballast.

The ideal isolation of intake and discharge fl ows 

is not always possible. However, in two pump 

ballast systems where fl exibility in the ballasting/ 

deballasting time is acceptable, it is recommended 

that one pump be dedicated for ballast intake and 

one for discharge. Transfers between tanks should 

be done by the ‘discharge’ or ‘clean’ pump unless 

treatment is active in the ballast tanks (as with 

de-oxygenation). 

Sampling & In-Service Testing

Port State Control and other authorized regulatory 

offi cers may, at any time for the purpose of 

determining whether the ship is in compliance 

with the discharge requirements, come on board 

and take samples of the ballast water. Designing 

proper and convenient sampling and testing 

facilities should be considered an important part 

of the installation engineering. As noted in Section 

1 of this Advisory, IMO G2, Guidelines for Ballast 

Water Sampling, calls for the sampling to be a 

simple and speedy process, applicable at the point 

of ballast discharge and safe to the ship and crew. 

The G2 guideline further contains very specifi c 

requirements for size, location and maintenance of 

isokinetic sampling ports. 

Unfortunately, sampling and analysis methodologies to test for compliance with the Convention 

remain in development. While research is ongoing, 

there currently exists no specifi c guidance for the 

best way to take, handle and analyze samples. There 

are no protocols for the volume of water required, 

the conditions in which the samples are stored 

Invasive Species

The map shows the estimated 

distribution of invasive marine 

species. Many marine 

organisms are carried 

in ballast water or on 

the hulls of ships.

Sources: Benjamin S. Halpern, National Center for Ecological Analysis & Synthesis Graham Roberts, Jonathan Corum/The New York Times

High
(e.g., light, temperature, storage container), how 

biota collection from a sample is accomplished, the 

statistical method used to count biota, nor direction on sample disposal (e.g. can it simply be discharged?).

The sample volume and method for biota collection 

are key to the design of the sampling facilities. 

They should include fl exible hoses, holding tanks 

and work area. Unfortunately, with the sampling 

port required to be near the discharge that is often 

located in the engine room where space is limited, 

handling of signifi cant quantities of water may be 

diffi cult to arrange or simply impractical.

Maintaining Ballasting Flexibility

Ideally, full ballast system operational fl exibility 

can be maintained with the selected treatment 

system. However, providing for the treatment of 

all isolated ballast systems on board, maintaining 

maximum fl ow rates at all times and providing 

for stripping systems (eductors) to continue to be 

used, may not be necessary for particular ships 

or even cost effective. For example, a vessel that 

does not move signifi cant ballast during normal 

operations may not need the treatment system to 

handle full pumping fl ow rates. Eductor-based 

stripping systems may not need special attention if 

the full treatment course is completed in the tank 

before discharge, or if the eductor power water 

can be taken from a treated source. Dedicating 

ballast pumps for intake 

and discharge may reduce 

fl exibility but may simplify 

piping connections and 

lower the risk of crosscontamination. 

Obtaining As-built 

Vessel Information

For most existing vessels, 

detailed as-built drawings 

of the ship’s ballast piping 

system and engine room 

arrangement may not 

be readily available. 

Nevertheless, detailed 

dimensional information 

is required for all vessel 

systems and outfi ts that 

may be impacted by the 

new equipment in order to 

properly evaluate locations 

for equipment installation 

and piping runs and avoid interferences. Further, 

installation sequence planning requires a detailed 

understanding of routes for equipment access and 

the minimum clearances available. Availability 

of suitable equipment lifting points also needs to 

be documented. Gathering of this information 

is important to a smooth installation (as well as 

possible treatment selection decisions) and should 

not be overlooked. Advanced techniques using 3-D 

laser scanning technology may be useful in this 

regard. 

Making a Treatment System 

Selection

With such a wide array of ballast water treatment 

technologies available and the numerous, often 

competing constraints on any one system, the 

evaluation and selection of the best equipment 

is not straightforward. There are many factors to 

consider. This Advisory provides an overview of 

the principal considerations that an owner/operator 

should bear in mind when specifying a ballast water 

treatment solution. 

As a fi rst step in the evaluation process, the 

information contained in Table 10 should be 

considered. It summarizes the suitability of the 

primary treatment technologies with a range of 

vessel types and sizes.

ABS BALLAST WATER TREATMENT ADVISORY • 29
30 • ABS BALLAST WATER TREATMENT ADVISORY

As can be seen, in only a few cases are treatment 

technologies deemed unsuitable for particular 

vessel types. The selection process then must take 

up the details. As an aid for use in this process, 

a checklist of key questions and considerations 

has been included in the System Evaluation 

Checklist Section that follows. This can be useful 

in establishing criteria. The value and rating of each 

factor is left up to the individual responsible for 

making the decision on the systems to employ.

Table 10: Suitability of a Ballast Treatment System Type to a Vessel Type

Vessel Category Vessel Size Range Chlorine 

Generate

Chemical 

Apply

Filter & 

Radiate De-oxygenate Ozone Generate

Bulk Carriers

Handy-Handymax < 60,000 DWT Yes Yes Yes Yes Yes

Panamax-Kamsarmax < 60,000-90,000 DWT Yes Yes Yes Yes Yes

Capesize > 90,000 DWT Except Large Yes Except Large Yes Yes

Tankers

Handy < 35,000 DWT Some Systems Yes Some Systems Yes Some Systems

Handymax-Aframax 35,000-120,000 DWT Some Systems Yes Some Systems Yes Some Systems

Suezmax 120,000-180,000 DWT Some Systems Yes Some Systems Some Systems Some Systems

VLCC 200,000-320,000 DWT No, Too Large Yes No, Too Large Some Systems Some Systems

ULCC > 320,000 DWT No, Too Large Yes No, Too Large Some Systems Some Systems

Containerships

Feeder < 500-3,000 TEU Yes Yes Yes Yes Yes

Panamax 3,000-4,500 TEU Yes Yes Yes Yes Yes

Postpanamax 4,500-9,000 TEU Yes Yes Yes Yes Yes

Ultralarge > 9,000 TEU Yes Yes Yes Yes Yes

Other Vessels

Passenger Ship All Sizes Yes Yes Yes Yes Yes

Gas Carrier All Sizes Except Large Yes Except Large Some Systems Some Systems

Chemical Carrier All Sizes Some Systems Yes Some Systems Some Systems Some Systems

Ro/Ro All Sizes Yes Yes Yes Yes Yes

Combination Vessel All Sizes Yes Yes Yes Yes Yes

General Cargo All Sizes Yes Yes Yes Yes Yes

Fishing Vessels All Sizes Yes Yes Yes Yes Yes

OSVs All Sizes Yes Yes Yes Yes Yes

Note: For tankers, chemical carriers and gas carriers, some systems are not suitable, either because they are not designed to be 

installed in a hazardous atmosphere such as a tanker pump room or because they are not produced at the high capacity required 

for large tankers.
ABS BALLAST WATER TREATMENT ADVISORY • 31

Vessel Ballast System Particulars 

Owner Supplied Data

1. Ballast system arrangement

a. Total ballast capacity

b. Number of ballast tanks

c. Minimum/maximum ballast tank size

d. Are ballast tanks contiguous with cargo oil or other hazardous cargo tanks?

e. Dedicated set of heel control tanks (FW or SW)?

f. Number of separate ballast systems (not served by same pump)

g. Proper and convenient sampling and testing facilities 

2. Ballast system equipment

a. Number of ballast pumps and rating (fl ow rate and pressure for each)

b. Overall ballast rate (m3

/hour)

c. Ballast pump location (engine room, pump room, main deck, etc.)

d. Main ballast line confi guration (ring main or single line)

e. Type of stripping system, if any

f. Are all ballast system valves remotely operated?

g. Are ballast pumps/piping shared with other systems (bilge, fi re, cooling water)?

h. Number and location of sea chests (height above bottom)

i. Diameter of main ballast line to/from pumps

j. Number and size of spare circuit breakers on main switchboard

k. Estimated spare electrical capacity during ballasting operations

Evaluation Checklists
32 • ABS BALLAST WATER TREATMENT ADVISORY

Ship & Service Characteristics that Impact BWT Selection 

Owner Supplied Data

1. Ship type and capacity

a. Ship type: high ballast dependent or low ballast dependent

2. Ballast water handling practices 

a. On average, how much ballast is loaded or discharged at any given port?

b. What are the time constraints on ballast intake (how fast must it happen)?

c. Maximum required fl ow rate for intake of ballast 

d. What are the time constraints on ballast discharge (how fast must it happen)?

e. Maximum required fl ow rate for discharge of ballast

f. Sediment build up in tanks (little, moderate, signifi cant) 

g. Is treatment required for possible NOBOB condition?

h. Minimum time ballast is held in a tank between port calls

3. Ballast water characteristics

a. Are there freshwater ports encountered where ballast is taken in?

b. Minimum salinity of brackish water encountered 

c. Turbidity or silt content of port water (low, moderate, heavy)

4. Vessel service characteristics

a. Any unique service constraints or trading patterns regarding ballast use?

b. Is there trade to special BWT zones: California, Great Lakes, Australia, etc.?

c. Does active ballast management allow zero ballast discharge in some/all ports?

5. Ballast system characteristics

a. What are the gravity intake/discharge practices?

b. Can internal ballast transfer for trim, heel, bending moment control be 

 easily accomplished?

evaluation checklist
ABS BALLAST WATER TREATMENT ADVISORY • 33

Treatment Technology Factors 

Vendor Supplied Data

1. Treatment method 

a. Description of technology offered (all stages)

b. For UV system: lamp type, required minimum intensity and water clarity

c. For chemical: Required minimum dosage rate and minimum holding time

 Neutralizing agents – how created, stored, dosed?

 How long before safe to discharge?

 Chemicals generated on board or supplied as preparations?

d. For de-oxygenation: How much inert gas required?

 Minimum holding time

 Type of gas, fuel type and consumption to generate gas

2. Treatment system capacity

a. Overall treatment capacity (m3)

b. Overall treatment rate (m3

/hour)

3. Treatment system pressure drops

a. Expected pressure drops added by treatment system to main ballast fl ow

b. Quantity of ballast redirected for cleaning or sludge discharge

c. Is gravity intake/discharge possible with this system?

4. Equipment size and space requirements 

a. Total space required for treatment equipment

b. Size of largest single component 

c. Weight of largest single component

d. Space required for maintenance (element removal, etc.)

5. Materials, equipment protection (IP rating) and hazardous spaces

a. IP rating of components

b. EX rating of components

c. Any special risk assessments performed to date for hazardous space installations?

6. Power requirements

a. Average and maximum power requirements and operating voltage

b. Duration of maximum power consumption as function of ballast process

7. Impacts on ballast tank and pipe corrosion

a. Is there published R&D available regarding the impact on tank and pipe corrosion rates?

8. Health and safety (handling, operation, maintenance)

a. Quantity of treatment chemicals needed (per ton of ballast water treated) 

b. For active substances: a copy of the MEPC fi nal approval with recommendations

c. For active substances: Material Safety Data Sheets

evaluation checklist
34 • ABS BALLAST WATER TREATMENT ADVISORY

General Treatment System Considerations 

Vendor Supplied Data

1. Proven effi cacy and offi cial approvals

a. Copy of Type Approval Certifi cate issued by, on behalf of, a Government

b. System limitations or operating guidelines from Type Approval process

2. Vendor qualifi cations and reputation

a. Annual production capacity of manufacturer

b. Which components are custom made or incorporate new/novel technology?

c. How many units have been built at the factory to be used for this installation?

d. Client referrals for previously installed systems

3. Maintenance requirements and system reliability

a. How many units of similar capacity have been installed?

b. What is average duration of operating experience per unit?

c. What is standard maintenance protocol?

d. What is expected service life?

4. Simple operation: control and monitoring

a. Type of remote control system included

b. Ease of connection to primary control and monitoring system

5. Life cycle costs

a. Estimated power consumption for normal ballast operations

b. Fuel consumption expected for inert gas generation

c. Cost of consumables (chemicals, lamps, fi lter elements)

d. Expected frequency of resupply of consumables for planned system size

e. What major components are most likely to need replacement within 10, 15, 20, 25 years? 

 What is their cost?

evaluation checklist
ABS BALLAST WATER TREATMENT ADVISORY • 35

Challenges for Installation Engineering 

Owner Supplied Data

1. Intake/discharge isolation: cross-contamination

a. Can piping installation options provide good contamination protection?

b. Can intake and discharge pumps be isolated and dedicated to that service?

2. Sampling and in-service testing

a. Is there adequate space and facilities for sampling and testing?

3. Maintaining ballasting fl exibility

a. Can the treatment system options selected provide full ballast fl exibility?

4. Other

a. Is there space for all system components and ballast connections?

b. What are the access openings and routes for bringing in new treatment system components?

c. What are the access needs during system operation and maintenance?

d. Are switchboard modifi cations required?

e. Are control system modifi cations required?

evaluation checklist
36 • ABS BALLAST WATER TREATMENT ADVISORY

Technical Information for Ballast Water Treatment Systems 

The following pages summarize the key technical and performance data for treatment systems, which are 

currently being offered on the market that are in various stages of approval as of the publication of this 

Advisory. It should be noted that some ballast water treatment systems which use chemical biocides or deoxygenation may require additional treatment prior to the water being discharged into receiving waters.

Systems with Type Approval Certifi cation

1. PureBallast System, PureBallast 2.0 and PureBallast 2.0 Ex

2. Electro-CleenTM System (ECS)

3. OceanSaver® Ballast Water Management System 

4. Venturi Oxygen StrippingTM (VOS) System

5. Hyde GuardianTM Ballast Water Management System

6. NK-O3 Blue Ballast/Nutech O3

7. Optimarin Ballast System (OBS)

8. Hitachi ClearBallastTM System

9. GloEn-PatrolTM System

10. Union Ballast Water Treatment System

11. JFE BallastAce System

12. RWO CleanBallast System

Systems with Final Approval for Active Substances

1. Hamworthy SedinoxTM System

2. HHI EcoBallast System

3. FineBallastTM OZ System

4. Ecochlor® Ballast Water Treatment System

5. ARA Ballast System

6. BalClorTM System

7. OceanGuardTM Ballast Water Management System

8. BalPure® System

Appendix
ABS BALLAST WATER TREATMENT ADVISORY • 37

PureBallast System, PureBallast 2.0 & PureBallast 2.0 Ex

Methods: Filtration + ultraviolet/TiO2 (AOT)

Operational Notes: The system is based on advanced oxidation technology, or AOT. Titanium dioxide 

catalysts generate free radicals when hit by light.The radicals, whose lifetime is only 

a few milliseconds, break down the cell membrane of micro-organisms without the 

use of chemicals or the creation of harmful residues (the system was, nevertheless, 

approved under the G9 regime for Active Substances). During ballasting, water 

is processed through the fi lter to remove any particles or organisms larger than 

50 microns in size. It then passes through the AOT treatment to the ship’s ballast 

system. Back-fl ushing water is returned over board at the ballasting site. During 

deballasting, the fi lter is bypassed and the ballast water receives a second dose of 

AOT before being discharged overboard.

 The system has been further developed: the number of UV lamps were reduced 

and a more effi cient 40 micron mesh fi lter and a fl ow regulating valve were 

introduced. Both the PureBallast 2.0 and PureBallast 2.0 Ex systems have received 

type approval. 

Manufacturer: Alfa Laval, Norway

Link/Reference: www.pureballast.alfalaval.com

Approval Status: Final Approval for Active Substances, July 2007

 Type Approval, June 2008, Norway (PureBallast System)

 Type Approval, March 2011, Norway (PureBallast 2.0 and PureBallast 2.0 Ex)

APPENDIX
38 • ABS BALLAST WATER TREATMENT ADVISORY

Electro-CleenTM System (ECS)

Methods: Electrolysis/electrochlorination

Operational Notes: Disinfection is carried out directly by the electrical potential and by the generation 

of free chlorine, sodium hypochlorite, hydroxyl radicals and electrochemical 

oxidation through the creation of ozone and hydrogen peroxide. 

Manufacturer: Techcross Company Ltd., Republic of Korea

Link/Reference: www.techcross.net

Approval Status: Final Approval for Active Substances, October 2008

 Type Approval, December 2008, Republic of Korea 

APPENDIX
ABS BALLAST WATER TREATMENT ADVISORY • 39

OceanSaver® Ballast Water Management System

Methods: Filtration + hydrodynamic cavitation + de-oxygenation (nitrogen) 

+ electrodialytic process

Operational Notes: After fi ltration intense pressure pulses are used to create hydrodynamic cavitation 

of suffi cient intensity to rupture cell membranes and destroy particles and 

organisms. The ballast water is then super saturated by the injection of nitrogen 

causing the oxygen dissolved in the water to be released, leaving the water in the 

tanks defi cient of oxygen. The released oxygen and nitrogen is evacuated from 

the tanks via a controlled ventilation arrangement usually through a pressurevacuum device so as to avoid the further natural release of nitrogen over time and 

to prevent potential contamination by outside air. The fi nal stage of treatment 

incorporates an isolated electrodialytic process which is based on the principles of 

an electrochemical activation technology. This is applied to a small portion of fl ow 

(greater than 5 percent by volume) producing a disinfectant which is returned to 

the main fl ow after the cavitation and the nitrogen saturation. This greatly enhances 

the disinfectant properties. The activated substances naturally degrade over a very 

short period of time. 

Manufacturer: OceanSaver AS, Norway

Link/Reference: www.oceansaver.com

Approval Status: Final Approval for Active Substances, October 2008 

 Type Approval, April 2009, Norway

APPENDIX
40 • ABS BALLAST WATER TREATMENT ADVISORY

Venturi Oxygen StrippingTM (VOS) System

Methods: De-oxygenation + cavitation + lowering pH

Operational Notes: Inert gas is introduced into the ballast during intake through a venturi system. 

The cavitation caused in the venturi system damages the organism and is the 

fi rst stage physical treatment. The inert gas removes oxygen from the water and 

lowers the pH level. The ballast tanks are kept inerted to maintain the hypoxic 

condition. This condition kills living organisms during the holding period in the 

tank (one to 48 hours). There are no active substances used. 

Manufacturer: NEI Treatment Systems LLC, United States of America

Link/Reference: www.nei-marine.com

Approval Status: Type Approval, September 2008, Marshall Islands

APPENDIX
ABS BALLAST WATER TREATMENT ADVISORY • 41

Hyde GuardianTM Ballast Water Treatment System

Methods: Filtration + ultraviolet light

Operational Notes: During ballasting, water is processed through the fi lter to remove any particles 

or organisms larger than 50 microns in size. It then passes through the UV 

treatment and to the ship’s ballast system. Back-fl ushing water is returned over 

board at the ballasting site. During deballasting, the fi lter is bypassed and the 

ballast water receives a second dose of ultraviolet light before being discharged 

overboard. There are no active substances used. 

Manufacturer: Hyde Marine, Inc., United States of America

Link/Reference: www.hydemarine.com

Approval Status: Type Approval, April 2009, United Kingdom 

APPENDIX
42 • ABS BALLAST WATER TREATMENT ADVISORY

NK-O3 Blue Ballast System/Nutech O3

Methods: Ozone + thiosulphate neutralizer

Operational Notes: The conversion of oxygen into ozone is carried out by an electric discharge fi eld. 

Ozone is then injected into the ballast stream at the outlet of the ballast pumps 

and kills a percentage of invasive marine species by direct contact. The remainder 

of the invasive marine species are killed when the ozone reacts with bromine that 

naturally occurs in sea water to create other biocides. The ozone and bromine 

related biocides naturally decay. Only trace amounts of the bromine compounds 

remain in the treated water. If the levels are too high, a neutralizer injects 

thiosulphate to reduce them to acceptable levels. The ozone system produces a low 

concentration of active substances.

Manufacturer: NK Company, Ltd., Republic of Korea

 Nutech O3, Inc., Republic of Korea

Link/Reference: www.nkcf.com

 www.nutech-O3.com

Approval Status: Type Approval, October 2009, Republic of Korea

 Final Approval for Active Substances, November 2009

APPENDIX
ABS BALLAST WATER TREATMENT ADVISORY • 43

Optimarin Ballast System (OBS)

Methods: Filtration + ultravoilet light

Operational Notes: During ballasting, water is processed through the fi lter to remove any particles or 

organisms larger than 40 microns in size. It then passes through the UV treatment 

and to the ship’s ballast system. Back-fl ushing water is returned over board at the 

ballasting site. During deballasting, the fi lter is bypassed and the ballast water 

receives a second dose of ultravoilet light before being discharged overboard. There 

are no active substances used.

Manufacturer: Optimarin AS, Norway

Link/Reference: www.optimarin.com

Approval Status: Type Approval, November 2009, Norway 

APPENDIX
44 • ABS BALLAST WATER TREATMENT ADVISORY

Hitachi ClearBallastTM System

Methods: Flocculent injection + magnetic separation + fi ltration

Operational Notes: Coagulation technology forms magnetic fl ocs by adding and agitating a coagulant 

and magnetic powder to the sea water to capture plankton, viruses, mud and sand. 

A high speed magnetic separator collects the magnetic fl ocs and the residual fl ocs 

are removed with a fi lter separator. Onboard storage of premixed fl occulants/

chemicals required. Accumulation, storage and disposal of sludge is required. 

Manufacturer: Hitachi Plant Technologies, Ltd. and Mitsubishi Heavy Industries, Ltd., Japan

Link/Reference: www.hitachi-pt.com

Approval Status: Final Approval for Active Substances, July 2009

Type Approval, March 2010, Japan 

APPENDIX
ABS BALLAST WATER TREATMENT ADVISORY • 45

APPENDIX

GloEn-PatrolTM System

Methods: Filtration + ultraviolet radiation

Operational Notes: During ballasting, water is processed through the fi lter to remove any particles or 

organisms larger than 50 microns in size. The ballast then passes through the UV 

treatment unit utilizing high intensity, medium pressure UV lamps for sterilization 

and on to the ship’s ballast system. Back-fl ushing water is returned over board at 

the ballasting site. During deballasting, the fi lter is bypassed and the ballast water 

receives a second dose of UV before being discharged overboard.

Manufacturer: PANASIA Co., Ltd., Republic of Korea

Link/Reference: www.worldpanasia.com

Approval Status: Type Approval, December 2009, Republic of Korea 

 Final Approval for Active Substances, March 2010

 Type Approval for Explosion Proof System, June 2010, Norway
46 • ABS BALLAST WATER TREATMENT ADVISORY

APPENDIX

Unitor Ballast Water Treatment System

(Technology provided by Resource Ballast Technology)

Methods: Mechanical cavitation + ozone + sodium hypochlorite injection + fi ltration

Operational Notes: The ballast water is treated on intake only. Cavitation and the application of the 

disinfectants electro-chlorination with sodium hypochlorite and ozone oxidation 

all take place. A screen-type self-cleaning fi lter is installed after the pump for the 

physical separation. The cavitation creates very strong sheer forces that effectively 

rupture the aquatic organisms. Electrodes mounted inside the reactor vessels 

produce sodium hypochlorite at a concentration of less than1.5 ppm. A small 

ozone generator incorporated in the control system provides ozone at less than 

1.5 ppm. The ozone provides disinfection both in brackish and fresh water. Both 

these disinfectants degrade rapidly without any effect on discharged ballast. The 

disinfectants employed are produced within the system and thus no additional 

facilities for the storage, make-up or dosing of chemicals are required.

Manufacturer: Resource Ballast Technologies (Pty.) Ltd., South Africa 

Link/Reference: www.wilhelmsen.com

Approval Status: Final Approval for Active Substances, March 2010

 Type Approval, August 2010, South Africa
ABS BALLAST WATER TREATMENT ADVISORY • 47

APPENDIX

JFE BallastAce System

(using TG Ballastcleaner & TG Environmentalguard)

Methods: Filtration + chlorination + cavitation + residual control

Operational Notes: During ballasting, mechanical separation removes organisms larger than 35 

microns. Back-fl ushing water is returned over board at the ballasting site. Chemical 

dosing with sodium chlorine and sodium sulfi te preceeds a mechanical treatment 

with cavitation in multiple venturi tubes. A residual oxidizing agent is quenched by 

a reducing agent at discharge.

Manufacturer: JFE Engineering Corporation, Japan

(in cooperation with the Toagosei Group, Japan)

Link/Reference: www.jfe-eng.co.jp

Approval Status: Final Approval for Active Substances, March 2010

Type Approval, May 2010, Japan
48 • ABS BALLAST WATER TREATMENT ADVISORY

APPENDIX

RWO CleanBallast System

Methods: Filtration + electro-chemical oxidation

Operational Notes: A disk-type fi lter system is used for mechanical separation to 40 to 45 microns 

when taking in ballast water followed by the EctoSys® disinfection unit. This unit is 

an electro-chemical system utilizing electrodes with high oxygen over potential that 

produces powerful disinfectants such as hydroxyl radicals and also provides direct 

oxidation of microorganisms on the electrode surface. No chemicals or precursor 

substances are added to the ballast water. Neither the hydroxyl radicals nor any of 

the theoretically produced by-products are bio-accumulative or persistent. Ballast 

water can also be run through the disinfection unit at discharge.

Manufacturer: RWO GmbH, Marine Water Technology, Germany

Link/Reference: www.rwo.de

Approval Status: Final Approval for Active Substances, July 2009

 Type Approval, December 2010, Germany
ABS BALLAST WATER TREATMENT ADVISORY • 49

APPENDIX

Hamworthy SedinoxTM System

Methods: Filtration + electrolysis (chloride ion disinfectant)

Operational Notes: This is a two-stage treatment. The fi rst, the Sedimentor, is a hydrocyclone that 

removes sediment and biota during uptake. The second stage, the Termanox, is an 

electrolytic process based on the electrolysis of sodium chloride present in seawater. 

The Sedinox unit is the control system.

Manufacturer: Hamworthy, PLC, the Netherlands

 (formerly Greenship BV, the Netherlands)

Link/Reference: www.hamworthy.com

Approval Status: Final Approval for Active Substances, July 2009
50 • ABS BALLAST WATER TREATMENT ADVISORY

APPENDIX

HHI EcoBallast System

Methods: Filtration + ultraviolet light

Operational Notes: During ballasting, water is processed through the fi lter to remove any particles or 

organisms larger than 50 microns in size. The ballast then passes through the UV 

treatment unit utilizing high intensity, medium pressure UV lamps for sterilization 

and on to the ship’s ballast system. The UV lamps are arranged in a unique helix 

arrangement to maximize probability of exposure. Back-fl ushing water is returned 

over board at the ballasting site. During deballasting, the fi lter is bypassed and the 

ballast water receives a second dose of ultraviolet light before being discharged 

overboard. 

Manufacturer: Hyundai Heavy Industries, Republic of Korea

Link/Reference: www.hhi.co.kr

Approval Status: Final Approval for Active Substances, March 2010
ABS BALLAST WATER TREATMENT ADVISORY • 51

APPENDIX

FineBallastTM OZ System

Methods: Cavitation (by high shear) + ozonation 

Operational Notes: The system uses an inline pre-treatment to preventing blockage of the disinfecting 

unit followed by a mechanical treatment via a special pipe and then adding ozone 

to the water. The ozone-treated water is stored in the ballast tank for at least 48 

hours to allow for the oxidizing and disinfecting properties of bromate (generated 

from the reaction of ozone and seawater) to become ineffective. The half-life period 

of the bromate ion is, on average, 12 hours. The unit then decomposes the oxidants 

remaining in the ballast water at the time of discharge. The ozone generator 

contains multiple electrodes which convert a part of oxygen in the gas to ozone. 

The power supply unit converts the power type from commercial frequency and 

low voltage to medium frequency and high voltage which is most suitable for ozone 

generation. A gas/liquid separation unit is employed to prevent ozone that does not 

react from fl owing into the ballast tank. 

Manufacturer: Mitsui Engineering & Shipbuilding Co., Ltd., Japan

Link/Reference: www.mes.co.jp

Approval Status: Final Approval for Active Substances, October 2010
52 • ABS BALLAST WATER TREATMENT ADVISORY

APPENDIX

Ecochlor® Ballast Water Treatment System

Methods: Filtration and chlorine dioxide (ClO2) treatment

Operational Notes: The system uses a two-step treatment process. The fi rst step is fi ltration with 

a 40 micron stainless steel mesh fi lter. The second step is the generation and 

injection of chlorine dioxide into the incoming ballast water stream. The fi lters 

are placed in close proximity to the ballast water pumps, but the treatment system 

can be installed in any convenient location on board the vessel.

 The fi lter unit uses a fi lter-cleaning technology that does not require typical backfl ush cycles. This allows for continuous fi ltration without signifi cantly reducing the 

amount of water that can be fi ltered during ballast water uptake.

Manufacturer: Ecochlor, Inc., United States of America

Link/Reference: www.ecochlor.com

Approval Status: Final Approval for Active Substances, September 2010
ABS BALLAST WATER TREATMENT ADVISORY • 53

APPENDIX

ARA Ballast System

(Basic Approval as Blue Ocean Guardian BWMS)

Methods: Filtration + ultraviolet light + plasma 

Operational Notes: The system operates during ballasting and de-ballasting. The fi ltration module 

serves to reduce the infl ow of organisms in the ballast tank to a minimum. This 

fi ltration module does not allow for the piling of sediments. The ballast then 

passes through the medium pressure ultraviolet light (MPUV) module and then 

the plasma module. The water is re-treated by MPUV during de-ballasting to avoid 

possible regrowth of aquatic organisms in the ballast water tank. 

Manufacturer: Samkun Co., Ltd., Republic of Korea

Link/Reference: www.samkunok.com

Approval Status: Final Approval for Active Substances, October 2010
54 • ABS BALLAST WATER TREATMENT ADVISORY

APPENDIX

BalClorTM System

Methods: Filtration + electrolysis (sodium hypochlorite)

Operational Notes: In the fi rst stage, ballast water is fi ltered by an automatic backwashing fi lter with 

a 50 μm screen to remove warm organisms that are larger than 50 micons. During 

the disinfection stage a small side stream of the fi ltered ballast water is delivered to 

the electrolytic unit to generate the oxidants of high concentration (mainly sodium 

hypochlorite solution), then the oxidants are injected back into the main ballast 

stream to provide disinfection. If the residual TRO level in the treated ballast water 

exceeds 0.1 ppm a sodium thiosulfate solution is added to the discharge pipe to 

neutralize residual oxidants.

Manufacturer: Qingdao Sunrui Corrosion and Fouling Control Co., People’s Republic of China

Link/Reference: www.sunrui.com.cn

Approval Status: Final Approval for Active Substances, October 2010
ABS BALLAST WATER TREATMENT ADVISORY • 55

APPENDIX

OceanGuardTM Ballast Water Management System

Methods: Filtration + electrocatalysis + ultrasonic treatment

Operational Notes: The mechanical fi lter (full automatic backfl ushing) has a fi lter mesh of 50 microns 

that is used to remove particles and viable organisms greater than or equal to 

50 microns in minimum diameter. The biological effi cacy is achieved mainly 

through active substances generated in water. The ultrasonic treatment acts as 

a supplementary treatment to the electrocatalysis. To make sure that the ballast 

water being discharged can satisfy the requirements of Regulation D-2, a second 

ultrasonic treatment is required.

Manufacturer: Qingdao Headway Technology Co., Ltd., Norway

Link/Reference: www.headwaytech.com

Approval Status: Final Approval for Active Substances, October 2010
56 • ABS BALLAST WATER TREATMENT ADVISORY

APPENDIX

BALPURE® System

Methods: Filtration + electrolysis (hypochlorite and hypobromite derivatives)

Operational Notes: A small side stream of ballast water is delivered to the electrolytic unit 

(electrolyzer) after passing through a fl ow orifi ce and fl ow transmitter that 

provides confi rmation of proper fl ow. The seawater which passes through the 

electrolytic unit generates oxidants (hypochlorite and hypobromite derivatives). 

The solution of depleted seawater, oxidants and hydrogen gas then passes through 

a patented cyclone to separate the hydrogen. The hydrogen is diluted with air 

using a blower to a safe level. The oxidants are injected back into the main ballast 

stream on the discharge side of the ballast pump(s) to match the seawater-oxidant 

demand. The biocides react in the pipe with both inorganic and organic species 

in the ballast water to provide effective disinfection as the harmful organisms 

and non-indigenous species which are inactivated and/or destroyed the oxidant 

concentration in the ballast water is reduced to 1 ppm. During de-ballasting sodium 

sulfi te is added to the suction side of the de-ballasting pump which instantly reacts 

and neutralizes residual oxidants. The processes are recorded in a data log and can 

easily be downloaded by authorities to confi rm successful treatment. 

Manufacturer: Severn Trent De Nora, LLC, Germany

Link/Reference: www.balpure.com

Approval Status: Final Approval for Active Substances, October 2010

TX 04/11 6000 11052

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