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What Treatment Systems are on theMarket?
SAFEMED III – Ballast Water Training
EMSA, Lisboa - 3rd/4th September 2014
Brian Elliott
Senior Project Officer for Environmental Protection
EMSA
Why Ballast Water Management?
• Approximately 3-4000 million t discharged every year in ports
• More than 10000 marine species transported every day in ballastwater accross the oceans
• Serious disturbance or alteration of ecosystems by invasive alienspecies (IAS)
• Ballast water most significant pathway of unintentionalintroduction of IAS
• Possible major socio-economic damage
• Possible threats to human health, e. g. through consumption of
contaminated food
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Why Ballast Water Treatment?
• Considered BW reception facilities
• Large amount of Ballast Water
• High cost for providing infrastucture
• Not all BW is discharged in ports
• Ships need to discharge at see to maintain stability andsafety.
• Ships need to discharge BW to enter shallow seas
• Ships need to discharge ballast water to enter port
• In order to catch and reduce all risks then treatment onship is the only option
• D-1 Standard – 200nm (50nm) – 200m deep. Cont shelf
• D-2 Standard - log (factor -4) reduction of normal levelsof plankton = reduction of 10000 to 1
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BWM Techniques (I) • Solid-liquid separation (usually precedes chemical
physiochemical unit process)
1. Filtration:
In BWM usually backwashing system
BWM standards are size based ―> mesh size between10 and 50µm most common
More effective for larger particles/organisms
2. Hydrocyclones
Alternative technology to filtration
Water injected at high velocity ―> rotational motionof the water leads to separation of particles fromwater
Effectiveness depends on difference in density of
particle and surrounding water, size of particlespeed of rotation and residence time
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Solid-liquid separation (examples)
a) Filter Source: Lloyd’s Register 2012 b) Hydrocyclone
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BWM Techniques (II)
3. Coagulants:
Can be used to increase efficiency of filtering orhyrdocyclones;
Time dependent
Requires big tank
Efficiency can be increased by adding ancillary powder ofhigh density (e. g. magnetite or sand)
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Disinfection (I)• Chemical Disinfection
Chlorination/Electrochlorination: relatively inexpensive, butvirtually ineffective against cysts. Can lead to undesirablechlorinated by-products.
Ozonation: fewer harmful by-products, but requires relativelycomplex equipment to both produce and dissolve it into thewater
Chlorine dioxide: normally produced on the spot, but critical(reagents used are themselves hazardous)
Peracetic acid: infinitely soluble in water, few harmful
byproducts, relatively stable as Peraclean. Problem: relativelyexpensive, dosed at high level and require considerablestorage facilities
Hydrogen peroxide: see peracetic acid
Menadione / Vitamin K: natural product and safe to handle
• Pre-treatment desirable (filtering, hydrocyclones); post-treatment of residuals necessary
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Disinfection (II)• Physical Disinfection
Ultraviolet irradiation: most well established method; wellknown to be effective against wide range of micro-organisms(e. g. viruses and cysts); relies on good UV transmissionthrough the water ―> clear water and unfouled clean quartzsleeves needed for effectiveness; removal of water turbidityessential; UV can be enhanced by combining with anotherreagent, such as ozone, hydrogen dioxide or titanium dioxide
Deoxygenation: takes a couple of days to come into effectdue to the length of time it takes organisms to beasphyxiated
Cavitation: acts at the surface of the micro-organism anddisrupts the cell wall through the collapse of micro bubbles
Ultrasonic treatment: see cavitation
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Ballast Water Treatment Unit Processes applied byIndustry – 42 different systems.
• Solid-liquid separation:
Hydrocyclones: 3 systems
Filtration: 27 systems
Coagulants: 1 system
None: 11 systems
• Chemical disinfection:
Ozone: 7 systems
Chlorine: 3 systems
Electrochlorination: 12 systems
Menadion/Vitamin K: 4 systems
Rest: 4 systems
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Ballast Water Treatment Unit Processes applied by
Industry (II)• Physical disinfection:
UV: 14 systems Deoxigenation: 5 systems
Heat: 1 system
Cavitation: 5 systems
Ultrasound: 2 systems
Advanced oxydation: 5 systems
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Any questions?
Thank you very much for your attention!