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CQD Journal for the Maritime Environment Industry Volume 3, #5 - December 1997, Copyright 1995 Edward M. Miller Associates, Inc. |
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Marine Environmental Symposium 1997Grey Water and Bilge Water Ultrafiltration for Oily Wastewater Biofouling Protection with Pulsed Electric FieldsBlasting and Ship Repair |
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From The Editor Dear Clients and Friends: Marine Environmental Technology This issue focuses
directly upon Marine Environmental Technology. ASNE's biennial event, the Marine Environmental Symposium '97 served as the arena upon which we investigated the technologies for this month's articles. Those technologies
which we feel merit applause are presented in outline format, the key speaker mentioned directly. The technologies detailed are those applicable directly to ship owners and port facility operators. In this month's issue we
pinpoint promising technologies for the commercial maritime industry. Readers can look to these as innovative solutions to present and potential future marine environmental problems. Chris Swanson |
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Environmental Symposium '97 Virginia Beach, VA - November 12 & 13, 1997 Those who were able to attend ASNE-Tidewater's marine symposium should not have left too
disappointed. Other than some missing keynote speakers, the sponsors were successful in directing a well varied account. There appeared to be more Exhibitors and Attendees present than past years, perhaps a testimony to the
emerging importance of marine environment issues. We have chosen three speeches as specifically significant to the maritime industry. For purposes of brevity, technologies are presented in the following outline format:
Focus - The point of the technology and how it works Pluses - Advantages to the maritime industry Minuses - Disadvantages with respect to the maritime industry Applicability to Commercial use -
As indicated The contributions of two centers of applied technology were significant in bringing commercial applications to the ASNE symposium. They are Virginia's Center for Innovative Technology (V-CIT) in Portsmouth
, VA and the Center for Advanced Ship Repair and Maintenance (CASRM) based in Old Dominion University. Thanks! |
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Grey Water and Bilge Water The U.S. Navy is spending a lot of effort on reduction and treatment technologies for grey, black and bilge water. Much of these efforts are in
anticipation of stricter international and domestic standards expected in the 21st century. Membrane ultrafiltration seems to be the technology of choice and is demonstrating promising results in trial studies aboard ships.
Michael Mull of John J. McMullen Associates Inc. pointed out that the membranes operate in a type of "reverse osmosis" fashion. These systems are successful because they can operate long periods without becoming
fouled. Other positive attributes are low maintenance and low manpower requirements. Replacement units are designed to plug in easily. More importantly, the technology is a modification of existing equipment
used in conventional shore based treatment plants. Viability is already proven, modification to ship specifications is the test. Email |
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Ultrafiltration Membrane Polishing System for Shipboard Treatment of Oily
Wastewater Focus: High-tech oil water
separation for bilge water using cross flow membrane technology. This technology takes oil water separation to highest environmental levels, reducing oil in bilge water effluent to less than 5ppm. Reduces the amount of
stored oily waste to bare minimum. The technology uses commercially available tubular ultrafiltration ceramic membrane bundles and modifies it for use on U.S. Navy ships in line with a UV disinfection system. Pluses:
Current prototype specifications are a small footprint (only 15 ft2, weighing 2,500 lb.) and a processing flow rate of 3 gal/min. During shipboard tests 70,000 gals. were processed in 15 months of operation.
The membrane acts as a secondary process in the treatment train reducing oil in pre-separated bilge sludge by an additional 98%. End result is a 100:1 reduction of oily waste in bilge water. Minuses:
Completion deadline uncertain. Research tests have been progressing for four years and are still in the prototype stage. Final application could be 1-2 years away. Applicability to Commercial Use:
While naval systems are often different from commercial ones, the small footprint and reasonable weight make the technology attractive if it can be retrofitted to market vessels. Navy ships and large commercial vessels retain
their oily waste for onshore disposal, creating storage problems and high port costs. Watch for the first commercial use on passenger cruise liners who's organizers are particularly sensitive to bilge water discharge and
other marine environmental problems. Cruise lines, reluctant to discharge contaminated bilge water are likely to have similar storage and disposal problems as the Navy. This will be a prime area for the first commercial
applications of reduction/decontamination technology of this nature. |
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Biofouling Protection with Pulsed Electric Fields Focus: Proactive approach to biofouling
protection, based on the theory that fouling organisms attach to the sides of the pipes and propagate from there. Technique: apply a pulsed electric field at the input/inflow/inlet pipes of a marine system ( i.e.
engine, plant, etc.). The electric field stuns potential biofouling organisms present in the flowing water. Stunned organisms cannot attach to the walls of the pipes, therefore keeping pipes clear. Pluses:
CASRM consortium is researching the economics of pulse strength and duration, determining optimum values of each variable to ensure the biofoulers are stunned for the full length of time that they are in the marine
system. Instead of applying an expensive kill charge the idea is to apply a less expensive stun charge. The research takes the position that applying a stun charge is more feasible, easier and much less expensive than a
kill charge. Minuses: Still in the study stage. Long wait until commercial use is available. Uncertain power requirements. Applicability to Commercial Use:
One of the major drawbacks to applied electronic technologies that combat biofouling has been the large power drains and space requirements for prototype systems. Both power and space are severely restricted on commercial ships. Stunning rather than killing the organisms is an innovative approach which makes sense if it means less power and cost. The key to this technology is the ultimate footprint and power usage both must be small. Biofouling of input pipes in marine engines is an enormous time and money drain for commercial fleets. If workable, this technology should be embraced voraciously by shippers.
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Blasting and Ship Repair Focus: Pollution prevention at shipyards. Combat the significant
environmental hazards created by conventional ship hull blasting by encapsulating the blasting mechanism. CASRM designed and built a prototype vehicle which uses recyclable steel shot mixed with grit to plaster the bottom
section of ship hulls within a sealed blasting arm. Concurrently, the machine contains dust and debris within the pivoting head. The shot is reused throughout the process, requiring replenishment normally only after the
completion of the entire bottom. Pluses: Advantages are immediately apparent upon viewing the video of the blaster in progress. Noticeably absent are the massive dust clouds of grit and paint found in a
normal sand blasting operation. The gimbaled arm rides along the ship's bottom guided by the one-manned blasting vehicle. Manpower is reduced to the driver/operator and the end product is a brilliantly clean hull.
Steel shot used is about 1200 lb. for 17,000 ft2 at an approximate cost of $0.15/ft2. Best of all, other ship yard operations can be going on at the same time. The same cannot be said for
conventional blasting as all other shipyard operations are closed during blasting for health, safety and visibility reasons. Minuses: Not many. Navy officials were concerned that a recycling blasting
process would put chlorine back into the hull. Current CASRM studies show this to be unsubstantiated. Limitations of angles on the gimbaled arm make this technology only feasible for the ships bottom and gently curving
sections. Conventional blasting would still be required on the remaining portions of sides and sharp angles. Applicability to Commercial Use: Enormous environmental savings. Potential cost
savings could be significant as well due to reduced blasting manpower, better end product, reusable grit and the fact that the entire shipyard does not have to shut down during blasting. Shipyards would do well to investigate
this technology as soon as possible. This makes sense! |
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Proceedings from Environmental Symposium '97
when available can be obtained by contacting the American Society of Naval Engineers (ASNE) directly at (757) 490-5140: Some other speeches we are considering for future issues include:
Please send us some feedback if you would like us to comment on any or all of the above topics! Miller Associates: |
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CQD Journal for the Maritime Environment Industry is published by E.M. Miller Associates, Inc., Florham Park, NJ. www.cqdjournal.com All rights reserved. Copyright 1999. |
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This page last updated by Miller Associates: Thursday, June 05, 2003 |
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