[Digestion] Digestion Digest, Vol 12, Issue 9
Alex Marshall
MarshallAl at rpsgroup.com
Wed Jun 6 11:16:19 CDT 2007
Dear Digestion Mailing List
It often frustrates me that there is little integrated thinking between
different digestion systems and industries. It seems that farmers, water
industry and the waste industry all deal with the technology largely
independently of each other. Why does it seem that the link up is so
poor? The power industry in the UK is starting to wake up to the
embedded generation potential of AD systems and may well bring a more
rounded approach. Does anyone know of any systems that are integrated,
handling a wider range of feedstocks or with a broader-minded approach?
Alex Marshall - Senior Consultant
Waste Technology Team
RPS Planning & Development, Severn House, 1-4 Fountain Court, Woodlands
Lane, Bradley Stoke, Bristol, BS32 4LA
( Direct dial: 01454 284480 ( Switchboard: 01454 284450 ( Mobile:
07810 156627
2 Fax: 01454 284499 * email: marshallal at rpsgroup.com
web: www.rpsgroup.com/waste
-----Original Message-----
From: digestion-bounces at listserv.repp.org
[mailto:digestion-bounces at listserv.repp.org] On Behalf Of
digestion-request at listserv.repp.org
Sent: 06 June 2007 17:00
To: digestion at listserv.repp.org
Subject: Digestion Digest, Vol 12, Issue 9
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Today's Topics:
1. Re: Digestion Digest, Vol 12, Issue 8 (stan simon)
2. Pasteurization: 1. HX , 2. When? (Duncan Martin)
----------------------------------------------------------------------
Message: 1
Date: Tue, 5 Jun 2007 16:09:11 -0500
From: "stan simon" <slsimon at tds.net>
Subject: Re: [Digestion] Digestion Digest, Vol 12, Issue 8
To: <digestion at listserv.repp.org>
Message-ID: <002801c7a7b5$c574bdf0$4a9a1545 at COMPUTER1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Regarding the energy requirements of pasteurization, it seems that a
heat exchanger could be utilized to cool the out going flow, this heat
could be directed to the flow being pasteurized, thus the heat
requirement would be lessened.
If discharging into a public sewer, some sort of cooling would generally
be required.
One purveyor of AD systems pasteurizes twice, both on incoming flow and
out going flow. My understanding of the incoming pasteurization is to
minimize unwanted bacterial species. They have a means of establishing
and retaining the desired bacteria so that the outgoing flow does not
depopulate the reactor. The second pasteurization is more of a "feel
good thing" to make regulators happy.
Stan L Simon, P.E.
S. L. Simon Engineering P.A.
8060 160th Av NE
Kerkhoven, MN 56252
320-264-5354 Phone/Fax
320-894-1117 Cell
slsimon at tds.net
----- Original Message -----
From: <digestion-request at listserv.repp.org>
To: <digestion at listserv.repp.org>
Sent: Tuesday, June 05, 2007 5:20 AM
Subject: Digestion Digest, Vol 12, Issue 8
> Send Digestion mailing list submissions to
> digestion at listserv.repp.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
> or, via email, send a message with subject or body 'help' to
> digestion-request at listserv.repp.org
>
> You can reach the person managing the list at
> digestion-owner at listserv.repp.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Digestion digest..."
>
>
> Today's Topics:
>
> 1. Re: Microlagae spriulina feedstock (David Fulford)
> 2. Re: Microlagae spriulina is a "good" feedstock (jc clerc)
> 3. References to Dennis Burkes' addresses, numbers, and
> materials... (JGBellHimself)
> 4. Article[s] about XL Dairy Group; and their web site....
> (JGBellHimself)
> 5. Infinifuel biodiesel plant in Wabuska uses geothermal energy
> and crops to create alternative energy (JGBellHimself)
> 6. Directory: Biofuels from Algae Oil (JGBellHimself)
> 7. Inactivation of pathogens (Claudia wendland)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 04 Jun 2007 17:09:51 +0100
> From: David Fulford <d.j.fulford at reading.ac.uk>
> Subject: Re: [Digestion] Microlagae spriulina feedstock
> To: adkarve <adkarve at pn2.vsnl.net.in>,DIGESTION at LISTSERV.REPP.ORG
> Message-ID: <5.2.1.1.2.20070604170424.0482ef38 at pophost.rdg.ac.uk>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> Apologies to the list, I should check my facts before making comments.
>
> The Phyllis data base confirms that there is very a good Nitrogen
content
> in algae. In that case, algae would make a good feed for a biogas
plant,
> even without other feedstocks.
>
> As others have suggested, the algae are good at cleaning polluted
water,
> so
> they could be used to concentrate the COD from dirty water for making
> biogas.
>
> Cheers,
>
> David
>
>
> At 11:44 03/06/2007 +0530, adkarve wrote:
>>Dear David,
>>as far as I know, green and blue-green algae are full of nitrogen,
quite
>>comparable to green leaves. One dry weight basis, Spirulina contains
70%
>>protein.
>>Yours
>>A.D.Karve
>
> *** Dr David Fulford, MSc Renewable Energy, Engineering Building ***
> *** School of Construction Management and Engineering ***
> *** The University of Reading, Whiteknights, ***
> *** Reading RG6 6AY, UK Tel: +44-(0)118-378 8563, ***
> *** Fax: +44-(0)118-931 3327 E-mail: D.J.Fulford at Reading.ac.uk ***
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 04 Jun 2007 18:52:47 +0200
> From: "jc clerc" <jc_clerc at hotmail.com>
> Subject: Re: [Digestion] Microlagae spriulina is a "good" feedstock
> To: d.j.fulford at reading.ac.uk, adkarve at pn2.vsnl.net.in,
> DIGESTION at LISTSERV.REPP.ORG
> Message-ID: <BAY113-F22E1175FB7D616125292D0E2210 at phx.gbl>
> Content-Type: text/plain; charset=iso-8859-1; format=flowed
>
> Thank you all for your replies.
> We can now consider that producing Spirulinais realistic as an only
> feedstock, also is is a positive way to take care of human waste/CO2.
> Thank's again and I'll share our results once we have tested this
> solution.
>
> Kind regards
> Jean-charles
>
>
>
>
>>From: David Fulford <d.j.fulford at reading.ac.uk>
>>To: adkarve <adkarve at pn2.vsnl.net.in>,DIGESTION at LISTSERV.REPP.ORG
>>Subject: Re: [Digestion] Microlagae spriulina feedstock
>>Date: Mon, 04 Jun 2007 17:09:51 +0100
>>
>>Apologies to the list, I should check my facts before making comments.
>>
>>The Phyllis data base confirms that there is very a good Nitrogen
content
>>in algae. In that case, algae would make a good feed for a biogas
plant,
>>even without other feedstocks.
>>
>>As others have suggested, the algae are good at cleaning polluted
water,
>>so
>>they could be used to concentrate the COD from dirty water for making
>>biogas.
>>
>>Cheers,
>>
>>David
>>
>>
>>At 11:44 03/06/2007 +0530, adkarve wrote:
>> >Dear David,
>> >as far as I know, green and blue-green algae are full of nitrogen,
quite
>> >comparable to green leaves. One dry weight basis, Spirulina contains
70%
>> >protein.
>> >Yours
>> >A.D.Karve
>>
>>*** Dr David Fulford, MSc Renewable Energy, Engineering Building ***
>>*** School of Construction Management and Engineering ***
>>*** The University of Reading, Whiteknights, ***
>>*** Reading RG6 6AY, UK Tel: +44-(0)118-378 8563, ***
>>*** Fax: +44-(0)118-931 3327 E-mail: D.J.Fulford at Reading.ac.uk ***
>>
>>
>>_______________________________________________
>>Digestion mailing list
>>Digestion at listserv.repp.org
>>http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
>>Beginner's Guide to Biogas
>>http://www.adelaide.edu.au/biogas/
>>http://info.bioenergylists.org
>
> _________________________________________________________________
> D?couvrez le Blog heroic Fantaisy d'Eragon!
> http://eragon-heroic-fantasy.spaces.live.com/
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 4 Jun 2007 11:42:29 -0700 (PDT)
> From: JGBellHimself <jgbellhimself at yahoo.com>
> Subject: [Digestion] References to Dennis Burkes' addresses, numbers,
> and materials...
> To: Paul Harris <paul.harris at adelaide.edu.au>, Richard Rainey
> <rgrainey at raineytvrosystems.com>
> Cc: DIGESTION at listserv.repp.org
> Message-ID: <238152.34142.qm at web34708.mail.mud.yahoo.com>
> Content-Type: text/plain; charset=ascii
>
> Good morning..., all...
>
> Some of you asked about how to find "Dennis Burke".
> Here are two things a little better than that:
>
> The following is a Dairy Waste Handbook that was prepared by Dennis
Burke
> in 2001
> and is posted on the Internet.
> If you use Google, and search for "Anaerobic Digestion", this is the
third
> item shown by Google.
>
> http://www.makingenergy.com/Dairy%20Waste%20Handbook.pdf
>
> What that reference also gives to you is Dennis' home page:
>
> http://www.makingenergy.com/
>
> As you can see, Dennis has been "in the game" for some time...
> and, unlike most AD system providers, he has been willing to share,
> publicly
> with US [in ofA and out]
> what he has been, and is, capable of doing.
>
> I have been looking at AD systems, sold here in the US, for a couple
of
> years now
> and this is, still, the most thoroughly thought out system that I have
> found.
>
> Once again, any thoughts about Dennis' AD system would be most
> appreciated.
> AND, any leads on better systems, technology, methods..., really would
be
> welcomed.
>
> Good'ay 2U2...
>
>
>
>
>
________________________________________________________________________
____________
> Need Mail bonding?
> Go to the Yahoo! Mail Q&A for great tips from Yahoo! Answers users.
> http://answers.yahoo.com/dir/?link=list&sid=396546091
>
> ------------------------------
>
> Message: 4
> Date: Mon, 4 Jun 2007 15:50:15 -0700 (PDT)
> From: JGBellHimself <jgbellhimself at yahoo.com>
> Subject: [Digestion] Article[s] about XL Dairy Group; and their web
> site....
> To: Paul Harris <paul.harris at adelaide.edu.au>, Duncan Martin
> <duncanjmartin at eircom.net>
> Cc: DIGESTION at listserv.repp.org
> Message-ID: <594363.93235.qm at web34710.mail.mud.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-7
>
> Morning to you...
>
> You have asked about the info about the AZ refinery that uses AD and
> algae:
> [the Nevada info will follow later]
>
> Trust that you will find this "little company" to spark your interest.
>
> attached below are some of the articles that I found and read...
> and
> this is their web site:
>
> http://xldairygroup.com/index.cfm?page=home
>
> as you will see, one article speaks to US$ 260 Million, and another
about
> US$ 400 Million.
>
> ---------------------
>
> The first article that we found was:
> by Julie Murphree at:
> Julie?s Fresh Air:
>
> http://juliemurphree.org/?p=45
>
> The second article appeared in Renewable Energy Access:
>
> http://www.renewableenergyaccess.com/rea/news/story?id=48223
>
> The third was in the local Phoenix newspaper:
>
> Land of milk and biofuel
> Ed Taylor, Tribune May 13, 2007
> Milk and biofuel might seem an odd combination, but a Phoenix-based
> company is planning to produce both at a proposed dairy/biorefinery in
> western Arizona.
>
> http://www.eastvalleytribune.com/story/89616
>
> ----------------
>
> Another article appeared in the local Wickenburg Sun:
>
> http://www.wickenburgsun.com/articles/2007/04/24/news/news15.txt
>
> ------------------
>
> And, a more business oriented article was in the Arizona Business
Journal:
>
>
http://www.nj.com/business/ambizdaily/bizjournals/index.ssf?/base/abd-3/
1179124802213310.xml
>
> And, finally, an industry article, various comments:
>
> http://www.greencarcongress.com/2007/05/arizona_dairy_g.html
>
>
>
>
> Building a website is a piece of cake.
> Yahoo! Small Business gives you all the tools to get online.
>
>
>
>
________________________________________________________________________
____________
> Be a better Globetrotter. Get better travel answers from someone who
> knows. Yahoo! Answers - Check it out.
> http://answers.yahoo.com/dir/?link=list&sid=396545469
>
> ------------------------------
>
> Message: 5
> Date: Mon, 4 Jun 2007 15:52:55 -0700 (PDT)
> From: JGBellHimself <jgbellhimself at yahoo.com>
> Subject: [Digestion] Infinifuel biodiesel plant in Wabuska uses
> geothermal energy and crops to create alternative energy
> To: Paul Harris <paul.harris at adelaide.edu.au>, Duncan Martin
> <duncanjmartin at eircom.net>
> Cc: DIGESTION at listserv.repp.org
> Message-ID: <446229.78219.qm at web34709.mail.mud.yahoo.com>
> Content-Type: text/plain; charset=ascii
>
> Here is info on the Nevada algae program:
> 1. an article:
>
http://www.nevadaappeal.com/article/20070513/BUSINESS/105130100
> and
> 2. their web site:
> http://www.infinifuel.com/
>
> ===========
>
> Oil from algae
>
> Infinifuel biodiesel plant in Wabuska uses geothermal energy and crops
to
> create alternative energy
> Karen Woodmansee
> Appeal Staff Writer, kwoodmansee at nevadaappeal.com
> May 13, 2007
> ------------ Photo w article
>
> Claude Sapp, president of Infinifuel Biodiesel talks about plans for
algae
> ponds at Infinifuel's site near Wabuska, Nev., on Tuesday. Sapp, is
> working in conjunction with the University of Nevada at Reno and the
> Desert Research Institute to use the algae as a biofuel source.
Infinifuel
> is not yet producing biodiesel from algae
> ---------------
>
> Gasoline prices over $3 a gallon, dire warnings about greenhouse
effects
> and increased pollution bringing about global warming are causing some
> folks to think more about energy alternatives.
>
> Claude Sapp, principal for Infinifuel Biodiesel, is one of those
folks,
> and now he is working to turn the oldest geothermal plant in Nevada
into a
> biodiesel processing facility, where camelina oil seed and even algae
is
> becoming diesel fuel.
>
> Sapp said any plant that produces high oil yields can someday power a
> vehicle.
>
> "Biodiesel is made from vegetable oil instead of petroleum," he said.
"We
> can get it from crambe, canola-type plants, oily seeds, even algae."
>
> He expects to have the first crop available in July, when a crop of
> camelina oil seed will be harvested and sent to a Lovelock plant to be
> crushed.
>
> Eventually, he hopes to have the plant at 15 Julian Lane in Wabuska
ready
> to grow its own algae, which he said can be harvested monthly.
>
> "It (algae) starts out in a test tube and replicates itself," he said.
"We
> can grow it in our test ponds. It is about a thousand times more
> productive to grow algae than growing oil seed in the dirt. We have
plenty
> of land to expand. We can grow acres more than our test ponds."
>
> Sapp said government researchers were initially skeptical about algae
> growing in Nevada's desert climate because of the cool nights, but
with
> the geothermal, Infinifuel can maintain a constant temperature.
>
> "We can grow more algae and harvest it more often than we can dry
crops,"
> he said.
>
> That doesn't mean dry crops don't have a future with Infinifuel. Sapp
said
> he has distributed oil seed to farmers from Eureka to Tonopah and
hopes to
> have enough to crush by summer.
>
> "We'll have some at 4,000 feet and 6,000 feet, so we'll get a good
idea on
> what grows where," he said. "Farmers from across the state have told
me
> they can't keep planting hay and alfalfa."
>
> The plant, which Sapp hopes puts out its first batch of biodiesel in
July,
> is almost entirely self-contained, said Sapp, and fits in nicely with
the
> ranching and farming environment around Wabuska and Yerington.
>
> It begins with algae or oil seed being nourished by the sun,
fertilizer
> and carbon dioxide, then crushed or pressed in a special facility to
> become vegetable oil and biomass. The biomass is added to alcohol,
where
> it is mixed with the vegetable oil and heated with geothermal power in
a
> biodiesel plant, where it becomes finished biodiesel.
>
> Glycerine, a byproduct of geothermal processing, can be used in dust
> suppression and the biomass, left over from the crushing and pressing
> process, becomes fertilizer or fish or animal food.
>
> The geothermal facility Sapp is using creates enough to power the
> biodiesel plant and even sell some electricity.
>
> "The water at the geothermal plant comes out of the ground at about
220
> degrees," Sapp said. "The plant makes electricity, with any excess
sold
> back to Sierra Pacific, so it is all self-contained. We're trying not
to
> use any petroleum products at all."
>
> The plant used to produce ethanol, back in the 1980s, Sapp said.
>
> "They tried to do corn ethanol," he said. "But when gas got cheap
again,
> they abandoned it."
>
> He doesn't expect that to happen again.
>
> "We got all the cheap stuff (crude oil)," he said. "All what's left is
the
> stuff that's hard to get to. There could be hundreds of years of it,
but
> it won't be easy or cheap."
>
> Sapp gave a tour of his facility last month to researchers from Desert
> Research Institute and engineers from Summit Engineering, hoping to
> partner with each in the future to improve his operation.
>
> "DRI is the research powerhouse in the state and Summit is the
engineering
> and building powerhouse in the state," he said.
>
> Del Fortner, energy and mineral manager for Summit, was impressed with
the
> concept.
>
> "The whole thing about renewable energy is it is so compatible with
other
> things around it, like agriculture," he said, pointing to cows grazing
> nearby. "They're putting a dairy across the street and he can get
> fertilizer from local ranchers."
>
> Kent Hoekman of DRI said the institute is interested in all types of
> energy research.
>
> "Making fuels from plants and the environmental impact of making
> geothermal and biodiesel we find interesting," he said.
>
> Sapp said he has expansion facilities planned in Hazen and Valmy, near
> Winnemucca and expects to grow thousands of acres of algae and oil
seed.
>
> "Valmy for sure," he said. "We have already secured land near the
power
> plant to grow algae and oil seed."
>
> He also doesn't plan to limit himself to Nevada, having picked up
> additional investors and land in North Carolina as well.
>
> ------------- Comments:
>
> Re: Oil from algae
> by Anonymous on Monday, May 14 @ 16:20:11 PDT
>
> This is great! Other companies like O2 Diesel are also doing this with
a
> variety of cellulostic and alternative oil/sugar producing
technologies
> for distillation.
>
>
>
>
________________________________________________________________________
____________
> Yahoo! oneSearch: Finally, mobile search
> that gives answers, not web links.
> http://mobile.yahoo.com/mobileweb/onesearch?refer=1ONXIC
>
> ------------------------------
>
> Message: 6
> Date: Mon, 4 Jun 2007 16:20:02 -0700 (PDT)
> From: JGBellHimself <jgbellhimself at yahoo.com>
> Subject: [Digestion] Directory: Biofuels from Algae Oil
> To: Paul Harris <paul.harris at adelaide.edu.au>, Duncan Martin
> <duncanjmartin at eircom.net>
> Cc: DIGESTION at listserv.repp.org
> Message-ID: <101308.63975.qm at web34706.mail.mud.yahoo.com>
> Content-Type: text/plain; charset="windows-1252"
>
> Gooday to U2:
>
> This is not only the last e-mail from me today, but probably for weeks
or
> months.
> In the mean time:
>
> "May your personal digestion keep working properly for you...!"
>
> IF you you are interested in Algae Oil
> you might want to take a look at this web site, and the information
> provided there.
> True, is looks as if it is primarily focused on "biodiesel".
> However, many new biodiesel efforts ARE looking at "algae" in very
> different ways.
>
> ----------
> Note the other research directories/info at the bottom
>
> ==============
> Directory: Biodiesel from Algae Oil
>
>
>
> The advantages of deriving biodiesel from algae include rapid growth
> rates, a high per-acre yield; and algae biofuel contains no sulfur, is
> non-toxic, and is highly biodegradable. Some species of algae are
ideally
> suited to biodiesel production due to their high oil content--in some
> species, topping out near 50%.
> ----------------
> http://www.peswiki.com/index.php/Directory:Biodiesel_from_Algae_Oil
> --------------------
> Table of contents:
> 1 Overview
>
> 1.1 About Algae
> 1.2 Biomass Yield
> 1.3 Oil Yield
>
> 2 Companies
>
> 3 In the News
>
> 4 Discussion Groups
>
> 5 Skeptics
>
> 6 See also
>
>
> Overview :
> About Algae:
> Oilgae.com (http://www.oilgae.com/) - Biodiesel from Algae Oil ? Info,
> Resources, News & Links
> Algae range from small, single-celled organisms to multi-cellular
> organisms, some with fairly complex differentiated form. Algae are
usually
> found in damp places or bodies of water and thus are common in
terrestrial
> as well as aquatic environments. Like plants, algae require primarily
> three components to grow: sunlight, carbon-di-oxide & water.
> Photosynthesis is an important biochemical process in which plants,
algae,
> and some bacteria convert the energy of sunlight to chemical energy.
The
> existing large-scale natural sources are of algae are: Bogs, marshes &
> swamps - Salt marshes and salt lakes. Microalgae contain lipids and
fatty
> acids as membrane components, storage products, metabolites and
sources of
> energy. Algae contain anywhere between 2% and 40% of lipids/oils by
> weight. There are three well-known methods to extract the oil from
> oilseeds, and these methods should apply equally well for algae too:
1.
> Expeller/Press 2. Hexane solvent oil extraction 3. Supercritical
> Fluid extraction
> Biomass Yield:
> Algal Biomass Yields versus Phytomass Yields of Tropical Crops
> (http://biopact.com/2007/01/in-depth-look-at-biofuels-from-algae.html)
> These are the yields obtained in stable cultures during an entire
year, as
> reported by the Aquatic Species Program. All other results from that
> program show either unstable growth or yields obtained over short
periods
> of time (often, during winter months when algae productivity drops
> significantly, the Aquatic Species Program discontinued the cultures.)
> Metric Tons/Hectare/Year
> M. minutum (algae), 1989.....35.8
>
> M. minutum (algae), 1989.....30.3
>
> M. minutum (algae), 1990.....38.3
>
> Algae (no species mentioned), 1978.....43.8
>
> Algae (no species mentioned), 1978.....51.1
>
> Sugarcane.....79.2 [Brazilian average, 2005]
>
> Sorghum.....70 [Average for Andhra Pradesh, India, 2005]
>
> Cassava.....65 [Nigeria, 1985]
>
> Oil palm.....50 [Global average, including low yields in Africa; in
> Malaysia, average yields are 75 MT/ha/yr]
>
> Arundo Donax.....50 [Grown in sub-tropics, Handbook of Energy Crops]
> Oil Yield:
> Cultivating Algae for Liquid Fuel Production
> (http://oakhavenpc.org/cultivating_algae.htm)
> Gallons of Oil per Acre per Year
>
> Corn . . . . . . . 15
>
> Soybeans . . . .48
>
> Safflower. . . . . 83
>
> Sunflower . . . 102
>
> Rapeseed. . . 127
>
> Oil Palm . . . . 635
>
> Micro Algae . .1850 [based on actual biomass yields]
>
> Micro Algae . .5000-15000 [theoretical laboratory yield]
>
> =============
> See also:
> Directory: Biodiesel
> Directory: Waste to Energy
> Directory: Biomass
> Green Algae for Hydrogen Production
> Directory: GeoBioreactors
> Directory: Microbial_Enhanced_Oil_Recovery
> Directory: Non-Fossil Oil
> Directory: Alternative Fuels
>
>
>
>
________________________________________________________________________
____________
> Be a better Globetrotter. Get better travel answers from someone who
> knows. Yahoo! Answers - Check it out.
> http://answers.yahoo.com/dir/?link=list&sid=396545469
>
> ------------------------------
>
> Message: 7
> Date: Tue, 05 Jun 2007 11:22:39 +0200
> From: Claudia wendland <c.wendland at tuhh.de>
> Subject: [Digestion] Inactivation of pathogens
> To: digestion at listserv.repp.org
> Message-ID: <46652B5F.2090503 at tuhh.de>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> In Germany it is required by law to pasteurise the feedstock in case
> there is organic waste added. Pasteurisation is quite energy
intensive.
> I made some experiments to acidify the feedstock (at 20 degrees for 5
> days) before feeding at pH around 4 and I got good results for
> inactivation of e-Coli.
> Has anybody experience with this type of pre-treatment?
>
> Claudia
>
> --
> ***********************************************************
> Claudia Wendland
> Institute of Wastewater Management and Water Protection
> Hamburg University of Technology
> Ei?endorfer Stra?e 42
> 21073 Hamburg
> Tel:+49 40 42878 3441
> Fax:+49 40 42878 2684
> c.wendland at tuhh.de
> www.tu-harburg.de/aww
> ***********************************************************
>
>
>
>
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> End of Digestion Digest, Vol 12, Issue 8
> ****************************************
------------------------------
Message: 2
Date: Tue, 5 Jun 2007 23:48:06 +0100
From: "Duncan Martin" <duncanjmartin at eircom.net>
Subject: [Digestion] Pasteurization: 1. HX , 2. When?
To: <digestion at listserv.repp.org>
Message-ID: <028c01c7a7c8$2e271700$c833869f at Dell1>
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*Heat Exchange*
Nice idea - but bear in mind that heat exchange works best on continuous
sterilization (rare in AD) or where you have an endless succession of
batch
processes and several pasteurizers. The minimum is a spare tank the
same
size. Otherwise, if you only have one pasteurizer, you have nowhere to
put
the warmed inflow until you have completely drained the previous batch.
Not
a huge expense however.
(Discharge to sewer must be pretty rare though?)
*When to pasteurize*
There is a logic to BEFORE - but if the feedstock contains solids it can
be
(a) hard to pass through heat exchangers, so process economy suffers and
(b)
hard to ensure full treatment because of slow heating inside the larger
lumps.
Pasteurization AFTER as a "feel good thing" to make regulators happy may
well be the honest truth - thanks Stan! But it's the kind of wasteful
folly
that should start us calculating the biogas yield from a batch of nice
plump
regulators! Well macerated, of course!!
I know of one small plant in Ireland, on Vicky Heslop's farm in County
Waterford, that has opted for pasteurization BETWEEN (only) - in a
two-stage
digester. There may be others in UK. I understand the regulators are
happy.
It avoids the above BEFORE problem - and also that of producing a
sterile
"broth" liable to reinfection, as mentioned in my posting a day or two
ago.
Duncan.
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