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Offline Gerard

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Assessment of biogas capacity from anaerobic digesters
« on: April 14, 2008, 10:32:00 AM »
Good day everyone,

i am now in the last term of my chemical undergraduate year,i am now conducting my research,assigned to me by the faculty, entitled: Assessment of biogas capacity from anaerobic digesters
i would like to ask for help on my research....
can anyone recommend me a free journal regarding this matter?
and what capacity parameters should i measure in this topic?
i would like to ask an expert regarding my research....
like:
what data to collect(test parameters,capacity)
how it will be analyzed and processed(methodology,calculations of the data collected)
what does these data tells or says...(results and conclusions)
i am not an expert in the biofuels particularly in the biogas so i really need an expert advice on this matter....
thank you all for the help....
-artifical student
"Charles! Charles! That's it Mr. Charles Darwin get out of this room, I told you once and I told you twice not to tease your fellow Mr. Arrhenius!"

Offline eugenedakin

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #1 on: April 15, 2008, 07:46:48 PM »
Hello Artificial Student,

Unfortunately, I do not know of a free journal which discusses biogas, although almost all university libraries have journals (electronic or print) which contains the details that you are looking.

Depending on which type of analytical instruments you have, depends on the data to collect.  For example, biogas can contain up to 75% methane:

http://en.wikipedia.org/wiki/Biogas

Analysis is typically through a Gas Chromatograph setup for gas samples (there are many other instruments that can work, but again, it depends on the equipment you have at your disposal).

Interpretation is a fine art...this you will repeatedly learn through your last year in studies. Try and maximize Methane production. 

The rest of the details that you are looking are usually found in the University Library.

I hope this helps you on your adventure in you last year  :)

Sincerely,

Eugene
There are 10 kinds of people in this world: Those who understand binary, and those that do not.

Offline Gerard

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #2 on: April 19, 2008, 11:53:26 PM »
good day,
thank you for the advise
i am quite confuse with the word "assessment of biogas capacity"
do we also need to asses the capacity of the biogas of the anaerobic digester? besides the "content" of the biogas?
furthermore do we need to analyze the "type" of the anaerobic digester being used?like calculating for the residence time of the substrate being used...the growth rate of the microbes and the production capacity and their yield?
-artificial student
"Charles! Charles! That's it Mr. Charles Darwin get out of this room, I told you once and I told you twice not to tease your fellow Mr. Arrhenius!"

Offline eugenedakin

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #3 on: April 20, 2008, 12:18:16 AM »
Hello artificial student,

Assessment of biogas capacity can mean many things. Please ask the person for further clarification.

Yes, you need to assess capacity, content, type, residence time, growth rate and yield... its quite the challenge.

If you get contamination in your system, all of the previous work you just did changes :)

I hope this helps.

Sincerely,

Eugene
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Offline Gerard

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #4 on: April 27, 2008, 03:25:00 AM »
good day,

thank you for your help,i manage to dig in into some books one is by Micheal Gerardi's "Microbiology of anaerobic digesters" the other one is "enivronmental engineering" by Gerard kelly, the other one is a seminar notes i enduringly scavenge in the trash can at the back of our department there are two  published notes the first one is :"microbiology of methanogenic processes" and the other one is "anaerobic treatment of wastewater"
i read a lot of references now but the notorious research comittee made my research even worse, they dont want me to patent or make my own digesters they want me and two other members to study working and dead digesters in my area how awful can it get?
my research adviser also did not agree to the change of scope of the topic but we have no power to disagree with them, they are more powerful than the faculty that is advising us....
anyway now here comes the problem....:how do i asses dead(non-working) anaerobic digesters?i cant even sample gas production,i dont know the solid retention time and the hydraulic retention time that it held during its operation and worse the bacteria inside the equipment mught long be dead...its hard to assume values that are deviating from the real values...
thank you for your help....
-artificial student
"Charles! Charles! That's it Mr. Charles Darwin get out of this room, I told you once and I told you twice not to tease your fellow Mr. Arrhenius!"

Offline Gerard

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #5 on: April 27, 2008, 03:42:21 AM »
thank you for your help eugene,
biofuel and wastewater engineering is really not my field of interest im more inclined into the biomedical and genetic engineering field....
-artifical student
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Offline eugenedakin

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #6 on: April 27, 2008, 09:18:53 AM »
Hello artificial student,

Interesting...

The positive aspect of working with non-working digesters, is that, at one time, they must have been working (no matter how poorly or efficient).

What you can do is determine flow-rates, surge flows, volumes, etc, and map out the process. This will provide a good starting point for more questions.  Mapping out the process will help you understand the methodolog that is being used, and newer reference information can explain how the newer 'working' plants are able to handle the capacity of biogas.

I hope this helps.

Sincerely,

Eugene
There are 10 kinds of people in this world: Those who understand binary, and those that do not.

Offline Gerard

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #7 on: April 29, 2008, 10:14:02 AM »
Hello artificial student,

Interesting...

The positive aspect of working with non-working digesters, is that, at one time, they must have been working (no matter how poorly or efficient).

What you can do is determine flow-rates, surge flows, volumes, etc, and map out the process. This will provide a good starting point for more questions.  Mapping out the process will help you understand the methodolog that is being used, and newer reference information can explain how the newer 'working' plants are able to handle the capacity of biogas.

I hope this helps.

Sincerely,

Eugene
-that is what i have been thinking,one of my attack to the problem was "the reactors were once working" so i presume there were records about the reactor performance when it was still alive (working), now i would like to ask what are the coniditons to reconsider a dead digeter to be rehabilitated back to working conditions?
is it the srt?,organic loading rate, biogas production,rate of degradation etc...i live in a tropical country so i guess temperature problems due to pocketed temperature differences is not a problem...
anyway this is just a few of my questions really because i am still at the early stage of my research which will psan for about 7 months so i still have many more questions to ask regarding my new toy:"the assessment of biogas capacity of anaerobic digesters in the community"
thanks for the help
-artifical student
"Charles! Charles! That's it Mr. Charles Darwin get out of this room, I told you once and I told you twice not to tease your fellow Mr. Arrhenius!"

Offline eugenedakin

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #8 on: April 30, 2008, 07:23:29 PM »
Hello artificial student,

You are thinking correctly.  It could be any on of the problems that you suggested:

Quote
is it the srt?,organic loading rate, biogas production,rate of degradation etc...i

Each system is different, and acts in a unique way.

Now, you must test many of the possible problems and determine which methods pass, and which ones fail.

I wish you the best during testing.

Sincerely,

Eugene
There are 10 kinds of people in this world: Those who understand binary, and those that do not.

Offline Gerard

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #9 on: April 30, 2008, 09:23:53 PM »
i have to test everything i know its not an esy task but hey worth the try.. :P
anyway i will be asking you to help me interpret some data if they are deviating or somewhat non-sensical is that okay?
thanks eugene...
-artificial student
"Charles! Charles! That's it Mr. Charles Darwin get out of this room, I told you once and I told you twice not to tease your fellow Mr. Arrhenius!"

Offline eugenedakin

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #10 on: May 01, 2008, 07:08:00 PM »
Hello artificial student,

Yes, I can help with interpretation of the data.  If you could provide process diagrams, etc.  This will help me visualize the process that you are using in the laboratory.  Also, write comments about 'subjective' data (you may not have an exact number for some visual observations).

I hope this helps,

Eugene
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Offline Gerard

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #11 on: May 04, 2008, 02:28:53 AM »
thank you for the help sir eugene, i will be starting with the dead digesters because i think its easy to control especially with the old records that they have, i can easily trace what went wrong with the digesters
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Offline eugenedakin

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #12 on: May 05, 2008, 08:11:48 PM »
artificial student,

I believe that you will learn a great deal about the plant from the old records.  I hope that you will have fun while learning  :)

I wish you the best.

Sincerely,

Eugene
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Offline Gerard

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #13 on: May 11, 2008, 01:31:01 AM »
good day,
i have started the review of my methodology an di encountered some problems beacuse all of the literature are based on aerobic digesters,are anaerobic digesters these rare?i cant use equations that are made for aerobic digesters....can you help me out with my inquiry? (o_O)?

1.)which is more favorable in measuring in an anaerobic digester?
BOD or COD,i think BOD is very difficult due to the absence of oxygen inside the digesters

2.)how to correlate BOD to COD?

3.)how to correlate methane production with bacterial activity?shall i use the michaelis menten equation?

4.)how can i determein the sludge age of a sludge from an anaerobic digesters?

5.)is it practical to monitor the COD or BOD, TKN, TON, TP of the influent and effluent? or shall i monitor these witht the samples that i took inside the digesters, i mean which is more pratical sample:influent,effluent or the sludge?

6.)whats the difference between the TKN and the TON?

7.)how can i measure the respiration rate inside the anaerobic digesters?

8.)what is the difference of the organic loading rate and the COD?
does it makes sense:if i change the COD the organic loading changes or if i change the organic loading rate the COD changes?
"Charles! Charles! That's it Mr. Charles Darwin get out of this room, I told you once and I told you twice not to tease your fellow Mr. Arrhenius!"

Offline eugenedakin

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Re: Assessment of biogas capacity from anaerobic digesters
« Reply #14 on: May 11, 2008, 09:19:30 AM »
Hi Artificial Student,

Excellent work, there is a good chance that you may need to perform some work from a laboratory perspective to get the details you are looking for. I will answer and provide guidance the best I can with your questions...here goes:

1) COD is measured first, because the test results are available in 4-hours. BOD test results are available in 5 days.

2) As a guesstimate (an estimated guess  ;)) the COD is 1/2 of the BOD. Microbes are notoriously horrible at math.  ;)

3) Each microbe has a different methane production. Determine the microbe that you are using and look up reports from there.

4) You can't. Each sludge is performed on a 'batch' basis.  Some batches will produce a large amount of methane, and some will produce a small amount of methane. This production rate also greatly depends on water concentration, feedstock and temperature.

5) Usually COD, BOD, TKN, TON and TP are required for the discharge of effluent. There is probably no need to perform this on the influent.

6) TKN is the sum of organic and inorganic nitrogen. TKN is determined int the same manner as TON except that the ammonia is not driven off before the digestion step.

7)The respiration rate is performed with a 'bench test'.  Because each microbe has a different reaction rate and production rate, this can only be performed by testing.

8 ) The loading rate greatly depends on the organics that you are adding to 'load' with. If the organics are readily decomposible by the local microbes, then there will be a low BOD. If the organics are difficult to decompose, then the BOD will be signifacently higher for the same mass of feedstock.

I wish you well,

Eugene
There are 10 kinds of people in this world: Those who understand binary, and those that do not.

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