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Subject: Biofilter crash & Sensor chips
Date: Thu, 1 Jun 2000 1:17:57 -0000 (GMT)
From: Dean Calahan |
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Say, I was recently reading Science News (since put in the recycling bin,
but within the last month), and there was an article on biofilters. The
filters they were talking about were little plastic balls or random media
covered with a biofilm.
Anyway, the interesting thing in the article was that the filters in
question had the undesirable property that, after working great for a year
or more, they would suddenly crash. It was hoped that some way would be
found to detect when a biofilter was about to crash and be able to
intervene.
Is this something that need concern us at this point? Is the "Trickling
Filter", indicated in the conceptual design document, an example of a
biofilter of this kind? From the scientific perspective, I guess I would be
interested anyway in knowing what is actually happening in the filter - both
in individual cells and throughout the structure of the biofilm. Sniffer
chips could be used to detect the presence or absence of various compounds,
while nucleic acid chips could be used to monitor gene expression.
- ---------------------------------------------
Mars Society Life Support Task Force
Email - life-support@chapters.marssociety.org
http://home.marssociety.org/tech/life-support/
Arctic Base - http://arctic.marssociety.org/ |
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Subject: Biofilter crash & Sensor chips
Date: Thu, 1 Jun 2000 15:37:38 -0000 (GMT)
From: Terry Kok |
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Dean,
First of all I would like to state that the conceptual
drawing on the life support website is a primitive
CELSS style system, much too large for FMARS. It
cannot be "started and stopped" as is needed for the
50 days per year inhabitation period we are restricted
to.
Biofilters of the type mentioned in the conceptual
drawing do tend to crash. I was just speaking with a
gentleman at the 17th annual ELF FEST who has a patent
on a much more advanced biofilter that does not crash.
Biofilters are alive. Life changes its environment, as
the environment is filled with the byproducts of life.
The gentleman I spoke with explained that his system
automatically changes its internal configurations to
follow the flow of life. It takes up less than 1/4th
the space of normal biofilters.
But, biofilters only convert ammonia to nitrite and
nitrite to nitrate. They are far from a complete waste
treatment and resource recovery system. Many more
components need to be added to the system to achieve
the final results required. In the Green CELSS Task
Force we are designing a much more effective system
(lower weight, size, complexity). This can be
accomplished by INTEGRATING MANY FUNCTIONS. The system
we are aiming for has only 2 units/parts. It will not
crash and it produces potable/distilled water and food
as well.
Since the FMARS grey water system must be small,
portable, light weight, and has to be started and
stopped within days of the inhabitant's
arrival/departure, I would suggest that we focus on
"none of the above" and place our attention on a
system which meets the mission criteria: an ALGAE
and/or GRASS based grey water system. Both of these
are good candidates.
Terry R. Kok - biostar_a@yahoo.com
Green CELSS Task Force focalizer
- --- Dean Calahan wrote:
> [to Life Support Task Force, from "Dean Calahan"
> ]
>
> Say, I was recently reading Science News (since put
> in the recycling bin,
> but within the last month), and there was an article
> on biofilters. The
> filters they were talking about were little plastic
> balls or random media
> covered with a biofilm.
>
> Anyway, the interesting thing in the article was
> that the filters in
> question had the undesirable property that, after
> working great for a year
> or more, they would suddenly crash. It was hoped
> that some way would be
> found to detect when a biofilter was about to crash
> and be able to
> intervene.
>
> Is this something that need concern us at this
> point? Is the "Trickling
> Filter", indicated in the conceptual design
> document, an example of a
> biofilter of this kind? From the scientific
> perspective, I guess I would be
> interested anyway in knowing what is actually
> happening in the filter - both
> in individual cells and throughout the structure of
> the biofilm. Sniffer
> chips could be used to detect the presence or
> absence of various compounds,
> while nucleic acid chips could be used to monitor
> gene expression.
>
>
> ---------------------------------------------
> Mars Society Life Support Task Force
> Email - life-support@chapters.marssociety.org
> http://home.marssociety.org/tech/life-support/
> Arctic Base - http://arctic.marssociety.org/
_
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- ---------------------------------------------
Mars Society Life Support Task Force
Email - life-support@chapters.marssociety.org
http://home.marssociety.org/tech/life-support/
Arctic Base - http://arctic.marssociety.org/ |
| |
Subject: Biofilter crash & Sensor chips
Date: Mon, 5 Jun 2000 1:27:24 -0000 (GMT)
From: John Ives-Halperin |
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Dean,
Terry R. Kok [biostar_a@yahoo.com] of the Green CELSS Task Force mentions in
an email on 6/1/2000 a patented wastewater recycling system. I was working
on the premise that we were to custom design a system. If there are
commercially available proven systems out there and there is no reason not
to use one, then I agree, lets try it.
Terry correctly points out that trickling filters serve principally to "...
convert ammonia to nitrite and nitrite to nitrate. They are far from a
complete waste treatment and resource recovery system. Many more components
need to be added to the system to achieve the final results required." The
trickling filter is only one element of the system we propose.
I also agree with Terry that size and start-up time are of paramount
importance. If CELSS (http://www.usu.edu/~cpl/celss.html) has minimized the
size and start-up time and it achieves the other mission goals, then let us
not reinvent the wheel.
The smallest working system we have up and running is too large for FMARS.
It is approximately 30 cubic meters designed to handle 378 dekaliters of
wastewater per day. Our plan was to engineer a smaller system to fit what
would probably be a smaller flow in the FMARS habitat. The design we posted
is based upon the installed system. We wanted to generate the very
discussion and criticism that Terry has offered. If CELSS is the best
choice, then lets use it.
The Maryland Task Force has not discussed start-up time as a group yet. I
was thinking we would use lyophilized bacteria cultures to jump start a dry
system. If the system has water at start-up, a condition I assume will be
true for FMARS, then the "start-up time" could be longer. In any case, I
believe start-up within a few hours or days is easily achieved with our
design. Stopping would be another matter. If dried out, it would stop
quickly. With water in the system it could take weeks to shut down. Does
this matter?
I have not seen the Science News article. So, my comments below may not
address the issues brought up in the article. If you were to locate a copy
on the web you might point me to it.
The biofilm referred to consists of microorganisms that find the media
conducive to life. It usually consists principally of bacteria, but algae
and other chlorophyll containing microbes can sometimes be found. In our
experience the media these organisms attach to can be of importance. In
fact, the interaction between the organisms and everything in their
environment can, under the right circumstances, be important. This is true
for the individuals, all of one species, and the entire group colonizing the
filter.
The trickling filter we proposed would have a synthetic media made of
recycled plastic. They look very much like whiffle balls, a bit smaller and
with more holes/surface area. Their specific gravity or buoyancy is one of
the important characteristic of the media proposed. The literature is filled
with the basic concepts behind trickling filter design (Reed, Sherwood C.,
et al. Process Design Manual: Land Treatment of Municipal Wastewater. US EPA
625/1-81-013. Center for Environmental Research, Cincinnati, OH 45268 and
Schmidt, Curtis J. And Boyle, William C. Design Manual: Onsite Wastewater
Treatment and Disposal Systems. US EPA 625/1-80-012. Office of Water,
Washington, D.C. 1980 and many others. For a more complete reading list you
might want to check out http://www.swg-inc.com/bibliography.htm).
A trickling filter is a biofilter. Without reading the article, I can't say
how similar the Science News filter is to our proposed filter. We have had
success with trickling filters. Of the few hundred I am aware of being
installed over the last 15 years I know of no catastrophic collapses. One
reason for this has to do with the ecologies developed to work in concert
with the trickling filter's microbial community. Some of this we control,
most occur without any more intervention then establishing the right
conditions for the communities and their ecologies to be established. Adding
a food source in the form of wastewater from the habitat supplies the energy
necessary and sufficient to drive all of the ecologies that appear. If the
nature or the amount of energy (food) supplied to the system changes,
collapse might occur.
The Maryland Technical Task Force is working within the principles of a
discipline called ecological engineering. One of these principles might be
formulated, "Nature knows best". I once heard John Todd say "There is more
intelligence in an ecosystem than in any man-made machine." Under this
guideline, we employ multiple ecologies to establish a robust treatment
system that resists collapse even when conditions change. One theory
suggests that complex ecosystems have many cryptic (hidden) or unexpressed
microbes within an ecosystem. They wait only for the environment to change
to make their presence known and felt. In any case, we are proposing the
designing and establishing of a complex group of ecosystems that support
each other across environments as well as within each environment. In this
way we hope to prevent any catastrophic collapse of the wastewater treatment
and recycling systems.
We are proposing a design element that functions like a trickling filter.
This element should perform as a biofilter in general and as an aeration
device in particular. There are many types of trickling filters using
various media. One of the advantages to using a trickling filter to add air
to the water is that while supplying air passively it also provide an
aerobic surface. This surface becomes colonized by microorganisms that
provide bio-filtration (removal of nitrogen, BOD and other nutrients). For
this project I think we should consider a waterfall type trickling filter.
This is what the National Aquarium in Baltimore, Maryland uses for cleaning
their recycled aquarium tank water. It seems to work very well for them. It
would have the additional benefit of providing an aesthetic amenity to the
habitat. If there is no room for such an amenity, then other configurations
are possible.
Your idea for a "sniffer" biochip is available for some compounds. There is
considerable interest in the research and the industrial communities in this
type of technology employed in the waste environment. Unfortunately, I am
not well informed on the state of this art. When I was, 10 years ago, we
were just beginning to build research grade sniffers in the laboratory. In
my lab, we were employing lipid bi-layer membranes with ionic channels
inserted in a polarized manner. This enabled us to detect extremely small
quantities of labile compounds as milli-volt changes across the membrane. I
believe the technology has moved far beyond our crude beginnings to growing
biological "chips" on wafers with detection, integration, and indicator
all-together on a single throw-away card.
I think it would be very interesting to monitor the habitat with these
biological devices.
I see I have run-on much too long...
Best wishes,
Hoop
- -----Original Message-----
From: owner-life-support@chapters.marssociety.org
[mailto:owner-life-support@chapters.marssociety.org]On Behalf Of Dean
Calahan
Sent: Wednesday, May 31, 2000 9:18 PM
To: life-support@chapters.marssociety.org
Subject: [life-support] Biofilter crash & Sensor chips
[to Life Support Task Force, from "Dean Calahan" ]
Say, I was recently reading Science News (since put in the recycling bin,
but within the last month), and there was an article on biofilters. The
filters they were talking about were little plastic balls or random media
covered with a biofilm.
Anyway, the interesting thing in the article was that the filters in
question had the undesirable property that, after working great for a year
or more, they would suddenly crash. It was hoped that some way would be
found to detect when a biofilter was about to crash and be able to
intervene.
Is this something that need concern us at this point? Is the "Trickling
Filter", indicated in the conceptual design document, an example of a
biofilter of this kind? From the scientific perspective, I guess I would be
interested anyway in knowing what is actually happening in the filter - both
in individual cells and throughout the structure of the biofilm. Sniffer
chips could be used to detect the presence or absence of various compounds,
while nucleic acid chips could be used to monitor gene expression.
- ---------------------------------------------
Mars Society Life Support Task Force
Email - life-support@chapters.marssociety.org
http://home.marssociety.org/tech/life-support/
Arctic Base - http://arctic.marssociety.org/
- ---------------------------------------------
Mars Society Life Support Task Force
Email - life-support@chapters.marssociety.org
http://home.marssociety.org/tech/life-support/
Arctic Base - http://arctic.marssociety.org/ |
| |
Subject: Biofilter crash & Sensor chips
Date: Mon, 5 Jun 2000 5:45:4 -0000 (GMT)
From: Erik Biermann |
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I tend to agree with Hoop on his last exposition. However I would like to
add a couple of statements to the discussion.
Trickling filters were initially designed to promote removal of organics
or BOD (Biochemical oxygen demand), and secondarily used for
ammonification and nitrification of the wastewater. They can easily be
designed to accomplish all of those tasks. In addition, they are quite
resilient since they are a biofilm community, as Hoop has stated.
They can also be started up quite readily using media, plastic shapes of
almost any sort, that has been started up previously and then dried.
Some of the organisms will not die during drying, but go into a dormant
phase. The media already innoculated with the dried biofilm will start up
readily when reintroduced to the wastewater. The biofilms also grow on
nearly everything and anything. The trick is to ensure that the biofilm
surface area per unit volume is high. This will ensure that a high mass
transfer rate occurs between the wastewater and the biofilm. I do believe
that the inclusion of a biofilm reactor as a component in the system will
be an asset.
Erik Biermann
- ---------------------------------------------
Mars Society Life Support Task Force
Email - life-support@chapters.marssociety.org
http://home.marssociety.org/tech/life-support/
Arctic Base - http://arctic.marssociety.org/ |
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