afe893fb78efd063d9cfbfb805f76c40.ppt
- Количество слайдов: 40
Ballast Water Management Engineering Technologies and Opportunities Spencer Schilling President Herbert Engineering Corp.
Overview Shipboard Ballast Operations Typical Ballast System Components AIS and Ballast Water Shipboard Ballast Water Management Solutions Exchange Treatment Technologies : Engineering Challenges
Shipboard Ballast Operations Why is ballast used? Maintain seaworthy condition when lightly loaded Draft, trim, stability, bending moment, shear force, slamming, propeller immersion, motions
Shipboard Ballast Operations How is it handled? Loading condition is assessed and ballast allocated to remain within safe operational limits Ballast movements coordinated with cargo operations Impact on Crew Provides for vessel safety Controls vessel motion for better comfort Requires daily management of ballast and maintenance of systems and tanks
Typical Ballast System Components Simple liquid storage/handling system Tanks, piping, valves, pumps Vents, overflows, sounding tubes, level indicators Remotely operated Sea chests and overboard discharges
Ballast System – Design Considerations Total ballast volume – 6, 000 to >100, 000 m 3 Flow rates – 200 to 5000 m 3/hr Head requirements – up to 30 m In service flexibility (# tks, pipe, valves, …) Ballast Exchange Options Partial Ballast Conditions Control systems
What are AIS? Aquatic Invasive Species (AIS) are organisms transported by human activities to a region where they did not occur historically and have established reproducing populations in the wild. (Ref. Dobroski, ‘Aquatic Invasive Species and Ballast Water Management’)
How do we manage AIS? Prevention – Best line of defense, vector management Eradication – Costly and often impossible, over $6 million to eradicate Caulerpa (algae) from two small southern CA embayments Species management once established – restrict local movement, control populations in sensitive habitats if possible (Ref. Dobroski, ‘Aquatic Invasive Species and Ballast Water Management’)
How do they get here? Many mechanisms (vectors) capable of transporting AIS around the world Aquaculture, live seafood shipments, bait, pet store trade, intentional release Commercial ships responsible for up to 80% of introductions in coastal habitats Includes ballast water and vessel fouling (Ref. Dobroski, ‘Aquatic Invasive Species and Ballast Water Management’)
Ballast Water and AIS Species are introduced upon ballast water discharge in recipient regions (Ref. Dobroski, ‘Aquatic Invasive Species and Ballast Water Management’)
Ballast Water Management Options in California Retain all ballast on board the vessel Ballast water exchange Discharge to an approved shoreside treatment facility (currently no such facilities in CA) Use of alternative, environmentally sound CSLC or USCG approved method of treatment (Ref. Dobroski, ‘Aquatic Invasive Species and Ballast Water Management’)
Ballast Water Treatment Standards Organism Size Class California 1, 2 IMO Regulation D-21 Washington Organisms greater than 50 µm in minimum dimension No detectable living organisms < 10 viable organisms per cubic meter Organisms 10 – 50 µm in minimum dimension < 0. 01 living organisms per ml < 10 viable organisms per ml Organisms less than 10 µm in minimum dimension < 103 bacteria/100 ml < 104 viruses/100 ml Technology to inactivate or remove: 95% zooplankton 99% bacteria and phytoplankton Escherichia coli Intestinal enterococci Toxicogenic Vibrio cholerae (01 & 0139) < 126 cfu 3/100 ml < 33 cfu/100 ml < 1 cfu/100 ml or < 1 cfu/gram wet weight zoological samples < 250 cfu/100 ml < 100 cfu/100 ml < 1 cfu/100 ml or < 1 cfu/gram wet weight zooplankton samples See Implementation Schedule (below) for dates by which vessels must meet California Interim Performance Standards and IMO Ballast Water Performance Standard [2] Final discharge standard for California, beginning January 1, 2020, is zero detectable living organisms for all organism size classes [3] Colony-forming-unit [1] Implementation Schedule for Performance Standards Ballast Water Capacity of Vessel Standards apply to new vessels in this size class constructed on or after Standards apply to all other vessels in this size class beginning in < 1500 metric tons 2009 2016 < 1500 – 5000 metric tons 2009 2014 > 5000 metric tons 2012 2016 (Ref. Dobroski, ‘Aquatic Invasive Species and Ballast Water Management’)
Treatment Technology Challenge Achieve desired kill rate Work at high flow rates and with large volumes Work with water of varying salinity, temperature, nutrients, clarity Do not introduce other personnel/environmental hazards Provide mechanism/process for testing/monitoring Do not disrupt ship operations/schedule Fit in limited space and survive ship conditions (vibration, pitch/roll motions, . . . ) Use available power Do not add to ship maintenance Be economical to buy, install, use and maintain
Treatment Technology Solutions Chemical Biocides (“Active Substances”) Chlorine (Generated on Board) Ozone (Generated on Board) Proprietary Chemicals (some delivered pre-mixed) Mechanical Separation - Filters Physical Change to Ballast Water Environment Irradiate (UV light) Deoxygenate Heat
Chlorine Na. Cl + H 2 O + 2 e Na. OCl + H 2 Generate Chlorine / Sodium Hypochlorate (bleach) with electrolytic cells on board Add solution when taking on ballast, maintain levels during voyage Lethal in hours >80% chance can meet IMO 2004 criteria Systems designed but limited testing to date High dosage levels can promote steel corrosion Concern about chemical residuals
Ozone generator on board using high voltage AC current Applied at uptake or discharge Lethal in 5 -15 hours Short half life limits corrosion and makes safe at discharge <60% chance can meet IMO 2004 criteria Systems designed but limited testing to date
Proprietary Chemicals Pre-Mixed proprietary chemicals introduced at metered dosage rate when taking on ballast Chemicals degrade over time, designed to be safe at discharge Lethal in 24 hrs >80% chance can meet IMO 2004 criteria Full size testing ongoing High dosage levels can promote steel corrosion Concern about chemical residuals Example Peracetic Acid C 2 H 4 O 3 acetic acid, hydrogen peroxide with sulfuric acid catalyst. Produced on shore, delivered to ship in chemical tanks
Mechanical Separation Filters and Cyclones Filters for larger organisms Done at uptake and/or discharge ‘Lethal’ at time of treatment <80% chance can meet IMO 2004 criteria Full scale testing on going
Filtration with Backflush 50 microns is the practical lower limit Automatic backflush is required to allow for unattended operation Backflush process reduces the net flow rate and increases the system pressure drops External backflushing pump is required Probably not practical for bulkers and tankers with high flow rates and volumes
Filtration with Backflush Can remove most of the larger life forms A 50 micron screen will remove most or all of the zooplankton and some of the phytoplankton and dinoflagellates. Filters of a practical size are not effective against bacteria and viruses Useful in reducing turbidity (suspended solids)
Cyclonic Separation figure
Cyclonic Separation Can remove solids heavier than the sea water and larger than about 50 microns About 5% to 10% of the total flow rate is removed in the sludge discharge Pressure drop is about 0. 8 bar plus backpressure valve at 1. 2 to 1. 5 bar
Cyclonic Separation Effectively remove the large vertebrates and invertebrates Not effective in reducing zooplankton density, but it does reduce live densities Not that effective in reducing bacteria, viruses, or phytoplankton
Physical Change to Environment Ultraviolet (UV) Light Inactivates living organisms by causing DNA mutations Proven effective against zooplankton, phytoplankton, bacteria and viruses. Need pretreatment to reduce size of organisms and exposure time Can be used on intake and discharge
Ultraviolet (UV) Light Can be automatically controlled and monitored Long history in the marine industry and demonstrated low maintenance requirements Basic technology is readily available on the market Turbid materials in the ballast flow attenuate and scatter the UV radiation
Physical Change to Environment Deoxygenate Inert gas generated on board When mixed with water, lowers Oxygen and p. H Lethal in 4 to 6 days >80% chance can meet IMO 2004 criteria Full scale testing on going, some systems approved by IMO Reduces corrosion, but can require closed tank vent system to maintain low oxygen atmosphere.
Physical Change to Environment Heat Treatment Heat water to threshold temperature (42 deg. C) Lethal in hours to days Requires large amount of energy and can be difficult to generate heat in port when ME not running <60% chance can meet IMO 2004 Criteria Full scale testing on going Heat promotes corrosion
Combined Systems Cyclonic + UV System (courtesy Optimar/Hyde Marine)
2 - Stage Treatment Cyclonic Separator + UV
3 - Stage Treatment Filter + UV + Chemical 50 micron filtration remove large particles remove sediments UV light inactivate living organisms reduced efficacy with cloudy water Catalysts activated by UV energy producing oxidizing chemicals increases efficacy of UV in cloudy water
Life Cycle Costs Acquisition 250 m 3/hr $100 k to $400 k 5000 m 3/hr $400 k to $1800 k Installation $50 k to $125 k $200 k to $800 k Operating $0. 02/m 3 to $0. 45/m 3 7000 m 3 $140 $3, 150 70, 000 m 3 $1, 400 $31, 500 Maintenance $ ?
Safety Issues Handling and storage of chemicals, radiation and other equipment meant to kill living organisms New risks to personnel and the environment IMO G 9 Procedures considering eco-toxicology, human health and ship and crew safety (MEPC. 126(53)) Local, State, National water quality regulations
Regulatory Compliance and Testing Stricter standards Testing is time consuming Lab results may not scale well to full size Functional testing and equipment certification “Type Approval”, or In service testing (“end of pipe”) for continuous monitoring Organism Size Class California 1, 2 Organisms greater than 50 µm in minimum dimension No detectable living organisms Organisms 10 – 50 µm in minimum dimension < 0. 01 living organisms per ml Organisms less than 10 µm in minimum dimension < 103 bacteria/100 ml < 104 viruses/100 ml Escherichia coli Intestinal enterococci Toxicogenic Vibrio cholerae (01 & 0139) < 126 cfu 3/100 ml < 33 cfu/100 ml < 1 cfu/100 ml or < 1 cfu/gram wet weight zoological samples
Need for Engineered Solutions Develop treatment technologies (Entrepreneur stage) Design testing methods and process for type approval or continuous monitoring Automatic ballast water analyzers (bug counters) Ship design adjustments and system integration Regulatory development/evaluation
Ballast Water Management Engineering Technologies and Opportunities Spencer Schilling President Herbert Engineering Corp.
afe893fb78efd063d9cfbfb805f76c40.ppt