Chemical Forums
Specialty Chemistry Forums => Chemical Engineering Forum => Topic started by: Gerard 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
-
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 (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
-
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
-
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
-
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
-
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
-
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
-
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
-
Hello artificial student,
You are thinking correctly. It could be any on of the problems that you suggested:
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
-
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
-
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
-
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
-
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
-
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?
-
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
-
good day,
thanks for the guidance,i have read that methanogens are quite difficult to culture so i guess this will be a tough job,ill be doing a one man platoon..
thanks for the guidance it really shed light to my inquiries especially the sludge age part...
i am now training on how to use the khjeldahl apparatus to take the TKN..
thanks prof!
-artificial student
-
I happened to stumble along youre dialouge here while searching out industiral gas production rates as a fubnction of volatile solids destruction.
After reading your post's it seems to me that you need to broaden your scope in terms of obtaining a comprehensive understanding of Anaerobic digestion.
I currently operate two such bio-reactors in New Jersey and have operate dozens of others over the last thirty or so years.
I would suggest that you spend some time researching at the water Environment Fedration website and on their chat logs. http://www.wef.org/Home
By the way no reactor symply "dies" unless it has undergone some form of toxic shock most reactors will have tell-tale signs of loss of efficiency such as large swings in VA/ALK ratios or increased Co2 - Ch 4 ratios.
I fyoud like to talk about his further please email me at EXDIR@SMRSA.org and I will gladly arrange a telphone interview to get you started on the right foot.
I also have a ton of realtime data thatg may be of interest to you
-
alli can say is "WOW!"
thanks for the help can we limit to email correspondence instead?uhm i really dont want to call you especially during unholy hours where you are quite busy with your works...e-mail correspondence is quite better in a manner that you can reply to me at your most convenient time...i also check the internet site and veiwed it and "WOW!" its really informative!
thank you for your help...i can place you and sir euegene in my acknowledge correspondence...
-
Sirs,
i have finished a draft of my crtical review regarding the microbiology of anaerobic digesters..i wouldlike you to critique it for me if there is anything lacking...uhm its still a draft so anything can happen
-
i have finished my first critical review...uhm....eugene you are invited to critique my paper
-
Hello artificial student,
Yes, I would like to read your paper.
Feel free to send it to my e-mail address :)
Sincerely,
Eugene
-
thanks eugene for the help but im unluckily i have some hindrance,this politician in my place is trying to "read" my review of related literature, i dond like politician they think they know everything,everything is very tehcnical in my papers but i dont think he well understand it he just nod whenever he encounters a very engineering term..how hippocritical can they get!..
i will send it to you soon after this so called biofuel "expert" will finish his scan on my papers...
thanks again
-artifical student
-
im back with a new sets of problem i encountered with my research...
i have a problem with how to take samples of biogas....
my adviser suggests that we buy the biogas bag which cost dollars..
my partner suggest we put it in a plastic bag smilar to that of the one where dextrose are filled and used in hospitals
and i suggest that we use car rubber interiors but the problem is will this affect the biogas characteristics?
next we dont know the standards of the biogas component to compare our results with..
-
Hi artificial student,
Yes, you could purchase a biogas bag, or you could just purchase a large disposible plastic syringe. Once you put the cap on the end, you limit cross contamination.
Just a thought... ;)
Sincerely,
Eugene
-
good day eugene,
will the methane diffuse if we use plastic syringe or anything plastic?ive seen syringe made up of glass and metals but they are very costly all i am planning is to use a cheaper alternative any suggestions?im eying on rubber will it be okay?
-
Hi Artificial Student,
Yes, there is a possibility that a small amount of the methane will diffuse throught the plastic syringe. Usually this takes a great deal of time when the syringe is not pressurized. If you pressurize the syringe, my guess is that much of the sample will eventually pass around the syringe.
Sincerely,
Eugene
-
im sooo tired!!!!!!
-
im sooo tired!!!!!!
do you still need researchpapers on the matter?
I think I have some stuff that might help, just let me know if you are still interested.
-
im sooo tired!!!!!!
do you still need researchpapers on the matter?
I think I have some stuff that might help, just let me know if you are still interested.
i dont only need research papers i need a contact person who can guide me all through out my research...
please do,i gravelly need a surmountable amount of research papers although i have started my research my proposal is still open to crticism thank you polleke...just send them to my email add thank you so much for the help
by the way eugene can i e-mail you my finish proposal tell me where it is open to criticism,thank you euqgen for the help....
-
Hello Polleke,
Yes, feel free to send a final copy to me and I will proofread it, along with providing helpful suggestions. Usually, the more people that you can get to look at it, the stronger your paper becomes.
Good luck! ;)
Sincerely,
Eugene
-
im sooo tired!!!!!!
do you still need researchpapers on the matter?
I think I have some stuff that might help, just let me know if you are still interested.
i dont only need research papers i need a contact person who can guide me all through out my research...
please do,i gravelly need a surmountable amount of research papers although i have started my research my proposal is still open to crticism thank you polleke...just send them to my email add thank you so much for the help
by the way eugene can i e-mail you my finish proposal tell me where it is open to criticism,thank you euqgen for the help....
Allright, I'll try and send it.
But be warned : I have a lot of articles and I do not know wich ones are intersting for you. So you will need to dig them out yourself.
I'll try to send them today.
-
im sooo tired!!!!!!
do you still need researchpapers on the matter?
I think I have some stuff that might help, just let me know if you are still interested.
i dont only need research papers i need a contact person who can guide me all through out my research...
please do,i gravelly need a surmountable amount of research papers although i have started my research my proposal is still open to crticism thank you polleke...just send them to my email add thank you so much for the help
by the way eugene can i e-mail you my finish proposal tell me where it is open to criticism,thank you euqgen for the help....
Allright, I'll try and send it.
But be warned : I have a lot of articles and I do not know wich ones are intersting for you. So you will need to dig them out yourself.
I'll try to send them today.
thank you so much for the help, you didnt help just me but many more, i am letting the other students read the file they are also working wiht anaerobic digesters with different search topics...this is for our sustainable energy alternatives studies
thank you....so much....
-
Well good luck with it.
I hope you received everything? I do not know how much mb you can store or receive with yahoo?
Anyway, if you need other articles you can always ask, if you search something in particular I might be able to help.
I can get many more articles , but its pointless to get them all and send them all while you might only be able to use 1 out of 100 lol.
anyway, good luck with the ones you allready have.
And I hope that the general book on biochemistry and physiology of anaerobic bacteria helps.
-
Well good luck with it.
I hope you received everything? I do not know how much mb you can store or receive with yahoo?
Anyway, if you need other articles you can always ask, if you search something in particular I might be able to help.
I can get many more articles , but its pointless to get them all and send them all while you might only be able to use 1 out of 100 lol.
anyway, good luck with the ones you allready have.
And I hope that the general book on biochemistry and physiology of anaerobic bacteria helps.
do you have any reference there regarding the constructionand operation of anaerobic digesters?i kinda aalso needs to sacn on them its not only the bacteria and methane production that i eed to consider uhm i also have to take considerations the manner that it is operated and constructed . :)
-
You need some information on the construction and operation of anaerobic digesters?
and:
kinda aalso needs to sacn on them its not only the bacteria and methane production that i eed to consider ==> I do not understand what you mean?
-
sorry for the misunderstanding:i also need the information on the construction and operation of anaerobic digesters....
becuase we will be assessing the follwing:
1.sludge
2.methane production
3.construction of the digester
4.the manner itis operated and maintained....
-
my first draft of the proposal was a reject!!!
the panelists comments was :"what is happening to you!?"
it was a slap on my face :-[
-
my first draft of the proposal was a reject!!!
the panelists comments was :"what is happening to you!?"
it was a slap on my face :-[
uh?
I do not get it?
The only comment you got was "what is happening to you?"
No other feedback?
and what are you doing exactly because I do not understand it.
You are working on a thesis? (graduation work ?) Or ?
-
im so sorry i was so shocked by the panelist's comment uhm my other request would be:
do you have any reference on how to construct and operate an anaerobic digester, references that asnwers questions like these:
1.how should a anaeroboc digester be constructed
2.where should it be constructed
3.how should it be operated
4.what physical parameters greatly influence methane production
5.what operational practices should be done to keep the anaerobic digester in good conditions for years
6.what operational practices to avoid
-
im so sorry i was so shocked by the panelist's comment uhm my other request would be:
do you have any reference on how to construct and operate an anaerobic digester, references that asnwers questions like these:
1.how should a anaeroboc digester be constructed
2.where should it be constructed
3.how should it be operated
4.what physical parameters greatly influence methane production
5.what operational practices should be done to keep the anaerobic digester in good conditions for years
6.what operational practices to avoid
those questions should not be any problem at all ;D
Just check the links and emails I gave you and maybe one of them will be able to help you.
I'll search around a bit myself and maybe I can get some info too.
Too bad that you are looking for the info at this moment: a lot of people are taking their holiday now.
But do not worry, there is no problem in getting that info.
PS. How long do you have before you need to finish your program?
-
we have 10 months to finish this research but all of us are panicking with a panel composed of demanding Ph.D's what can we do but follow thier commands after all they are the experts.. :-\
were all are disoriented right now and we cant focus (even me) because we keep on thinking about three things
1st our research in environmental biotechnology (my anaerobic digester stuff)
2nd my packed bed bioethanol fermenter (my equipment design research)
3rd an upcoming research for the plan process design..(means another 4 ours deduction of sleep)
i have to be honest,i am not good at environmental biotechnology....
id rather be in stem cell biology than this....but i have no choice...
-
Oh well, thats all part of it.
Do not panic, it wont do any good.
Did you get my latest private message here and my latest emails?
Do not forget to email those companies and persons, they might be able to give you a lot of details about how those installations are build.
I'll see if I can dig up some manuals about the construct and maintenace of anaerobic digesters. I am however not sure if I still have them (I do have them, but the question is where ;D)
But to be honest I do not completely understand it all.
The panel you are talking about they are just there to give grades? They do not asist?
And dont you have some supervisor that might help you?
And what excalty are you doing? A sort of thesis to graduate or ?
-
Oh well, thats all part of it.
Do not panic, it wont do any good.
Did you get my latest private message here and my latest emails?
Do not forget to email those companies and persons, they might be able to give you a lot of details about how those installations are build.
I'll see if I can dig up some manuals about the construct and maintenace of anaerobic digesters. I am however not sure if I still have them (I do have them, but the question is where ;D)
But to be honest I do not completely understand it all.
The panel you are talking about they are just there to give grades? They do not asist?
And dont you have some supervisor that might help you?
And what excalty are you doing? A sort of thesis to graduate or ?
a thesis for graduation,and uhm about the panel?
they give advises but it seems to contradict the advice of the other ppanelist...for exam this panelists wants us to do COD the other one doesnt want us to do COD..
another wants TOC and the other doesnt want TOC...
its a mess if you have a paleist who are such a perfectionist...
-
Hello artificial student,
I am sorry to hear about the confusion that you are going through. The good news is ... it only gets more confusing from you graduation on... Some countries require BoD tests, while others do not. Part of the reasoning is it actually depends on the local flora and fauna.
I wish you well, and be patient. It will all work out in the end.
Best wishes,
Eugene
-
it would be okay after i graduate cause i will be doing the research design my own way,,,but this thesis work...i am under control of some panelists...i told them that of they woul let me decide what to do ill just do a monitoring of the pH,Temp,alkalinity,TS,VS and COD thats all...
weeeewww tak about my faculty i cant understand them
-
it would be okay after i graduate cause i will be doing the research design my own way,,,but this thesis work...i am under control of some panelists...i told them that of they woul let me decide what to do ill just do a monitoring of the pH,Temp,alkalinity,TS,VS and COD thats all...
weeeewww tak about my faculty i cant understand them
;Dhéhé
Oh well, it will all work out ok.
Do not let them scare you or panic.
Any luck with the info I gave you? The links and email adress etc?
You did receice that email and personal message I send you here?
-
yes i did recieved the files,thank you for that and i used it as a part of my review of literature,i also shared the websites to another group because they will be fabricating a UASB and a stirred tank anaerobic reactor, it really helped us all...
thank you...
and alas!last defense of the proposals is on August 2, wish me luck...
-
yes i did recieved the files,thank you for that and i used it as a part of my review of literature,i also shared the websites to another group because they will be fabricating a UASB and a stirred tank anaerobic reactor, it really helped us all...
thank you...
and alas!last defense of the proposals is on August 2, wish me luck...
oh 2 august allready!
Thats in +- 1 week.
Well good luck then.
But after the defense of the proposals its all over? or it continues?
-
the agony lives on until the first week of january...
after the proposal we have to collect the data ,analyze it then process it for another defense...and this time it will be a defense that will determine if you pass the course or redo the whole research....
-
uhm one more thing do you have any info about bowl centrifuge for liquid-liquid separation?
-
the agony lives on until the first week of january...
after the proposal we have to collect the data ,analyze it then process it for another defense...and this time it will be a defense that will determine if you pass the course or redo the whole research....
Oh I see.
uhm one more thing do you have any info about bowl centrifuge for liquid-liquid separation?
Maybe, I'll have to check that.
I'll let you know if I find something.
-
Hello artificial student,
I have not seen bowl centrifuges used for liquid-liquid separation, but have been used very successfully for liquid-solid separation in the oilfield on a daily basis.
Liquid-liquid separation will remove dispersed material, but not soluble material. For example, oil dispersed into water can be separated with a high enough force, but dissolved salt (unsaturated sodium chloride) in water will not be separated by the bowl centrifuges I am familiar with.
I hope this helps.
Sincerely,
Eugene
-
that is the problem you see uhm i was assigned to do a research on the Bowl Centrifuge used in Liquid-Liquid Separation, i wonder what is the relationship to that with anaerobic digesters....anyway my proposal defense will be on august 5...
thank you all guys for helping me out wiht my thesis...i will need them more in the research proper...
-
Hello artificial student,
Hmmm.. interesting ... I am familiar with Bowl Centrifuges which are used in Biogas systems to remove the solids from liquids (which there are many), not the liquid-liquid separation. What liquids are you planning on separating?
The solids are removed from the liquids to minimize the solid material which can no longer be degraded.
Thanks for your thoughts.
Sincerely,
Eugene
-
tanks eugene for the clue...
can i ask?what is the main disadvantage of using COD compared to TSS and VSS?
-
Hello artificial student,
The two tests are very different, and the meaning for each of these tests are different. COD takes a long time (relatively speaking, such as 4 hours). TSS takes very little time (5 min to 30 min).
The disadvantage of using COD is that of time, but it is more accurate from a disposal point of view. TSS doesnt really tell you much about disposal, just the solids.
Sincerely,
Eugene
-
i was requested by my adviser to use only TS and VS to approximate the biodegradable amount of the solid waste manure..then one of my research mates asked me why i used TS and VS instead of COD i repiled that COD determines the whole carbonaceous compound in terms of oxygen demend not the biodegradable ones only and i also said that solid waste manure is quite difficult when treated for COD analysis...
am i right? by the way i will be designing a packed bed (immobilized cell bed) fermenter this is for my bioprocessing equipment design...i will also be asking for some guide tips about this soon if its okay with oyu guys...
-
Hello artificial student,
You mentioned:
then one of my research mates asked me why i used TS and VS instead of COD i repiled that COD determines the whole carbonaceous compound in terms of oxygen demend not the biodegradable ones only and i also said that solid waste manure is quite difficult when treated for COD analysis... am i right?
Hmm.. very good question, with a difficult answer. COD more represents a measurement of the organic compound in water (such as pollutants) which is often a measure of water quality. If you wanted to know the ability of a material to degrade, this is the test you would want to perform.
Total Suspended Solids was (in the old books) called non-filterable residue (NFR). If your worried about solids plugging your system, this is the test you would want to have.
There are many aspects to consider, and I hope this helps with the discussion between you and your collegue.
Great question!
Sincerely,
Eugene
-
we all debated about which method to use with sludge that contains more solid than liquid...
i agree with using the COD if the sample was mixed solid liqour (more of a liqufied animal maure) but i also said that if the waste we are going to analyze is really solid manure then we better use VS analysis to determine the biodegradable part.....still the debate is on and we are trying to prove our claims by doing the experiment.
alas you gave me another point of significance why i included TS in my studies that is to determine if the waste coming inside my digester contains enough solid to clog up the whole equipement..
thanks eugene..
p.s with regards to my research proposal it was nose bleed, all of the reviewrs were asking questions at the same time i cant determine which one i will entertain first!
-
this topic is now close!
thank you all for the help, it made my study both technical and conceptual in terms of the environmental engineering part, again thank you all
-gerard d. ompad
-
this topic is now close!
thank you all for the help, it made my study both technical and conceptual in terms of the environmental engineering part, again thank you all
-gerard d. ompad
How was your result ?
Were they satisfied, your professors?