1. IMO-IMarEST Shipbuilders’ Forum on
The Ballast Water Management Convention
1 November 2010
Singapore
Ballast Water Treatment System Installation Issues
A Class Perspective
A. K. Seah
VP Technology & Business Development

2. Outline
Brief review
Some issues in shipboard installation
Generation of hazardous gases
Tanker with low flash point products
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3. BWTS technology
Some 40+ vendors
Over half use mechanical system as primary means
Most used disinfectant technology: UV and electrolytic
chlorination, each has >10 vendors
>3 systems used combined mechanical, physical and chemical
processed
3

4. Ship size and ballast tank capacity
(m3/hr)
Source: ABS Ballast Water Management Advisory
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5. Implications
■ Ships keel-laid after 2012 - must allow for
installing BWT system at building stage
■ Ships keel laid before 2012 must have system
on board by 2017 - this means installing BWT
system in special survey drydocking window
of 2012-2016
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6. System selection
Technical feasibility
Dry cargo ships – any system
Tankers (flash point ≤ 60°C)
Ballast system piping in pump room – electrical
equipment must be explosion-proof or intrinsically safe
Aft peak ballast tank – a separate ballast system?
Fitting the system in
Footprint; Power need; Pressure drop; System supplier
special needs; Engineering issues
Side effects: ballast tank coating; accumulation of
hazardous gases…
Commercial considerations
System cost; cost of installation; operating cost;
maintenance cost
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7. Some issues on Engineering and
Shipboard Installation

8. Hazardous gases
Electrolytic chlorination process produces
hydrogen and chlorine
Hydrogen is flammable
Chlorine is toxic
Systems using electrolytic chlorination
process are now proposed for installation
Closer look at two systems
Techcross Electro-CleenTM
Unitor / Resource ballast Technology BWTS
8

9. Techcross Electro-CleenTM
Wholly electrolytic chlorination process
BW treated at intake; Neutralization at discharge
Permissible dosage of active substance as TRO at treatment <10 mg/l
Permissible concentration of active
substance TRO at discharge < 0.02mg/l
(sodium thioslphate)
S
TRC (Total Residual Chlorine) Tank
Vent
TRO (Total Residual Oxidants) Source: MEPC 58/2/7
9

10. Techcross – Electro-CleenTM
Received IMO Final Approval, 10 Oct
2008
Highest level of gas measured during
tests (as submitted to IMO):
H2: 4% [Threshold: LEL 4%]
Cl2: 0.9ppm [Threshold: 0.5ppm average
8-h work place exposure]
IMO approval based on provision of:
H2 online detection: alarm at 2%;
System was
shutdown at 3%
certified
Cl2 online detection: alarm at 0.6ppm; explosion proof
shutdown at 0.8ppm
Source: MEPC 58/2/7; Techcorss website
10

11. Unitor/Resource Ballast Technology
Combined cavitation, sterilization, physical
separation
BW treatment at intake
Disinfectant is provided by ozone (< 1.5ppm) and
by electrolytic chlorination (sodium hypochloride
< 1.5ppm) in reactor / cavitation chamber
Source: www.resource-
technology.com
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12. Unitor/Resource Ballast Technology
Received IMO Final Approval 26 Mar 2010
Highest level of gas measured at simulated tests of
200m3 ballast tank (as submitted to IMO):
Ballast water changed once daily for 8 days and twice
for the last 2 days; tank drained to 1/3 volume then
refilled to full capacity Ozonation
H2: 0.28% Electrochlorination
Cl2: 0.25ppm Cavitation
IMO approval based on
additional provision of:
De-aerator & H2 monitor
TRO monitoring/recording
at discharge
Source: MEPC 59/2/10, MEPC 60/2/11
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13. Issue of hazardous gases
Issue of flammable gases H2
Oil & gas industry practice: low gas alarm at 20% LEL, high
gas alarm at 60% LEL & shutdown
Proposal by Techcross: alarm at 2% (50% LEL) and
shutdown at 3% (75% LEL)
Additional shipboard tests showed H2 peaked at 0.03%
Proposal by Resource Ballast Technology: none; IMO require
H2 monitor but alarm point and shutdown not specified
Issue of toxic gas Cl2
No existing shipboard practice
Proposal by Techcross accepted by IMO
None proposed by Resource Ballast
Technology – acceptable to IMO
Tank entry; gas-freeing
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14. Effect of treated BW on corrosion
In general, appears non-conclusive
Techcross: tests showed seawater with TRO
concentrations had less or similar corrosion to natural
seawater
Contradicts known and published data that chlorinated
seawater increased corrosion
Resource Ballast Technology: tests showed corrosion
rate for steel in treated seawater about double that for
equivalent untreated seawater, but within reported
limits of normal corrosion rate
No known data on effect of ozone
IMO recommends:
Monitoring program to provide long-term effects
Parallel corrosion tests with tests for type approval
Source: MEPC 58/2/7, MEPC 59/2/10
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15. Effect of treated BW on corrosion
Techcross
Corrosion Tests
Coating intact
Coating with
artificial scratch
Source: http://techcross.koreasme.com/
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16. Safe spaces / Hazardous spaces
Tankers carrying cargoes with flash point
≤ 60°C
No connection between piping in safe spaces
(e.g. engine room) with piping handling liquid
in hazardous spaces (e.g. pump room; ballast
tank adjacent to cargo tanks, cargo tanks)
Some exceptions permitted provided safety
features are fitted
BWTS intended for tankers; e.g.:
Ozone dosing system
Aft peak tank – can it share BWTS with cargo
area ballast tanks?
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17. Dosing piping cross connection
Alternative
Located as
high in pump
arrangement:
room as dosing piping to
practicable enter pump room
from main deck
with vapor seal
With alarm and shut
down arrangement
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18. Sampling lines cross connection
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19. Aft peak tank
An acceptable arrangement
SYS = Ballast Water
Treatment System
BWTS would have to be a type that does not require treatment at discharge
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20. Aft peak tank
An unacceptable arrangement
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21. Summary
Many new ships have now contracted with
BWTS….existing ships are largely still
waiting in the wings
Some engineering and installation issues are
being debated and assessed
Important to examine in detail bases of
approval reported in MEPC papers in
installation engineering….and in operations
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22. www.eagle.org