Green
RO Pretreatment
Updated
10/13/09. See below in same font and color.
Updated
11/23/09. See below in same font and color.
Develop and demonstrate an alternative to
disposable filters or an improved disposable
filter design that can last at least four
months filtering somewhat turbid feed
water.
Currently
many sea going ships use disposable cartridge filters, such as a 5
micron filter or a two stage process with a 20 micron filter followed by
3 micron filter, as prefiltration to protect the reverse osmosis potable
water. This simple design works well in the open ocean, but closer to
shore or in areas with a lot of marine biology or suspended solids,
these cartridges have to be replaced often, even daily. On long voyages
several hundred replacement filters may be needed which takes up space
and requires significant maintenance time for changing the filters.
Disposal of used filters is also an issue and the used and fouled
filters usually have to be stored until they can be disposed of on land.
Develop and demonstrate an alternative to disposable filters or an
improved disposable filter design that can last at least four months
filtering somewhat turbid feed water. To increase the life of the
RO membranes, ideally your proposed processs will address particle size
down to 0.1 microns as there are suspended solids that do pass through
the current cartridge filters and foul the RO membranes.
Specific consideration will be given to technologies that have
potential cross-over for inland water desalination application.
You may assume that the RO recovery will be 40 percent and that a modern
energy recovery device will be used to minimize pump work. Also assume
that the target feed water is seawater filtered through a 500 micron
screen. For the inland water desalination plant, you may assume similar
screening conditions. Additionally the following must be considered
while designing your sea water treatment process:
·
The energy for the prefiltration process
cannot be more than 10% of that used for the
reverse osmosis operation.
·
The total space occupied by the new
prefiltration system producing 30,000
gallons per day cannot be more than three
times larger than if one were using just
cartridge filters (20 micron, 3 micron) in
series despite filtering to a much finer
level (equivalent of a 0.1 micron filter).
·
No hazardous chemicals can be used while the
vessel is at sea.
·
Base your assumptions on a 9-month time
frame.
·
The estimated volume of stored items
(replacements and chemical additives) for a
full size system filtering 30,000 gallons
per day must be less than 100 cubic feet (1
tenth the volume of the currently stored
filter elements assuming replacement every 4
days).
·
The maintenance of the new filter system
should be less than the current system
(cartridge filter replacement every 4 days,
four hours each time).
Each team is advised to read the Team Guide and Team Handbook for a
comprehensive understanding of the contest evaluation criteria.
Additionally, your proposed design will be evaluated on issues
identified in the problem statement as well as others listed here.
-
Originality
-
Ease of
use/maintainability
-
Reliability
-
Affordability
-
Innovative
-
Potential for
real-life use and implementation
-
Cost effective
operation
-
Functionality
and operability for large volume
The teams will need to return the processed
and unused portion of their sample. This
information will be
incorporated into the
evaluation criteria.
Bench-Scale
Demonstration
During the contest, each team will be required to demonstrate the
effectiveness of their process using 10 gallons of a mixture of the
following composition:
-
De-chlorinated tap water
-
32,000 ppm Sea Salt
-
75 mg/L Klamath Blue Green Algae Powder
-
20 mg/L Orchid Pro (by Turf Pro USA)
For
the purpose of sample preparation and
testing at the home institution, each team
should use the above recipe, mix it well and
strain it through a 500 micron screen. These
ingredients are available from most health
grocery, and/or garden supply stores.
The written report is the first presentation of your team’s
proposed solution. The report should give the reader a full
understanding of the magnitude of your team’s involvement with the
problem details. The report will be evaluated for clarity, logic,
coherence and quality. Standards appropriate for publications in
technical journals apply.
In addition
to the listed requirements, the following
must be discussed in your written report:
-
Describe
selection process in detail including
cost/benefit consideration, evaluation
criteria, and screening protocol.
-
Discuss
advantages, disadvantages, and
limitations of the selected tool and
other options considered.
-
Discuss
possible sterilization methods
-
Include recent
references and sources of information
-
Address any
safety issues or considerations
associated with the process.
-
Include a
marketing strategy and outreach plan.
Contact:
Barbara Valdez, Program
Facilitator
(575) 646-7821
(800) 523-5996
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