Search found 302 matches

by Bob
Tue Feb 03, 2009 11:26 am
Forum: Anaerobic Digester
Topic: using aerobic process to heat anerobic digester?
Replies: 2
Views: 11947

Re: using aerobic process to heat anerobic digester?

Idea 1: ...will the air kill the anaerobic bacteria Yes. It could also make a dangerous, potentially explosive fuel/air mixture. You don't want to do that. Your Idea 2 sounds too complicated and expensive. (I would use all the organic material I had available to make biogas from, and focus my effor...
by Bob
Sat Jan 31, 2009 3:29 pm
Forum: Anaerobic Digester
Topic: water re-use
Replies: 1
Views: 10543

Re: water re-use

Your operation sounds like it might better lend itself to a batch feed or hybrid system, rather than the continuous feed design I have described here. The US EPA AgSTAR Handbook and Software provides the information you will need.
by Bob
Sat Jan 31, 2009 3:23 pm
Forum: Anaerobic Digester
Topic: Stable waste
Replies: 1
Views: 10472

Re: Stable waste

Yes. A good source of information for farm-scale operations can be found at US EPA's website. In particular, check out their handbook and FarmWare software.
by Bob
Thu Jan 29, 2009 11:30 am
Forum: Anaerobic Digester
Topic: Energy indepentend home
Replies: 11
Views: 26830

Re: Energy indepentend home

As long as it is producing methane, then there is really no need to know everything.
True. If you can maintain the temperature and the pH you should be good. There are a number of inexpensive pH meters on the market that would be handier than pH paper.
by Bob
Thu Jan 29, 2009 10:38 am
Forum: Anaerobic Digester
Topic: Green waste
Replies: 1
Views: 10297

Re: Green waste

Yes. It sounds like a good feedstock. The fact that it has already started to rot should be a benefit.
by Bob
Wed Jan 28, 2009 4:48 pm
Forum: Anaerobic Digester
Topic: Energy indepentend home
Replies: 11
Views: 26830

Re: Energy indepentend home

Also, do you know where you can get some monitoring equipment, to monitor temperature,ph,co2,methane,and hydrogen sulfide? The short answer is yes. The longer answer would depend on how much you want to spend, how frequently you want to record the data, and how much you want to do manually vs autom...
by Bob
Tue Jan 27, 2009 6:07 pm
Forum: Anaerobic Digester
Topic: Energy indepentend home
Replies: 11
Views: 26830

Re: Energy indepentend home

Hi David, No time for more than a fly-by, but here's a link that has some good info on feedstocks and gas production. And David House's Biogas Handbook has this: Buswell [says]… “the present estimate is that from 5 to 10 cubic feet of gas can be obtained per pound of cornstalks, and that the rate of...
by Bob
Tue Jan 27, 2009 1:20 pm
Forum: General Catchall
Topic: alternative ventilation system
Replies: 1
Views: 10560

Re: alternative ventilation system

Are there any recent changes or results from your implementation of the design in Bristol Bay or elsewhere? Yes. We ended up abandoning the idea after installing it in about 20+ houses in 3 different villages, over a couple of years. But, that said, all of the problems had to do with site specific ...
by Bob
Fri Jan 16, 2009 11:12 am
Forum: Anaerobic Digester
Topic: Energy indepentend home
Replies: 11
Views: 26830

Re: Energy independent home

1- What would be the best crop to grow? That's probably a location-specific question, David. Rather than grow a crop specifically for fuel, you might consider feeding your digester agricultural 'waste' from other (perhaps more valuable) crops? Are you near an urban center -- like where people rake ...
by Bob
Thu Jan 08, 2009 2:42 pm
Forum: Anaerobic Digester
Topic: Homebuild digester and the pitfalls..
Replies: 7
Views: 22579

Re: Homebuild digester and the pitfalls..

...when paper is anaerobically digested it produces 4 times its paper weight in methane gas.. Is there any truth to this? Would you recommend putting shredded paper into an anaerobic digester? I don't know about the weight of gas per weight of feedstock, but it can be calculated from basic chemistr...
by Bob
Fri Jan 02, 2009 6:26 pm
Forum: Anaerobic Digester
Topic: Homebuild digester and the pitfalls..
Replies: 7
Views: 22579

Re: Homebuild digester and the pitfalls..

how do you keep the toilets clean? We used Shaklee products for years, until our local distributor moved away. After that we were able to find various other benign off-the-shelf products. But you're right. We didn't use bleach. Here is a photo of a 4-digester test setup I built recently, to test th...
by Bob
Thu Jan 01, 2009 7:06 pm
Forum: Anaerobic Digester
Topic: Homebuild digester and the pitfalls..
Replies: 7
Views: 22579

Re: Homebuild digester and the pitfalls..

Hi Mathew, I think I'd start by trying to get a rough estimate of quantities of waste and gas you can produce. Based on the quantities you describe (toilet wastes from a single family residence, a few chickens and some glycerol) I'd guess you probably can't generate enough gas to justify the cost of...
by Bob
Tue Dec 23, 2008 12:23 pm
Forum: Anaerobic Digester
Topic: Haiti Orphan Schoold electricity
Replies: 1
Views: 10559

Re: Haiti Orphan School electricity

Hi Lou,

Here is a digester design from Francisco X. Aguilar that may be suitable for your application. It is simple, minimum cost, and suitable for tropical environment. Little more than a polyethylene bag in a pit in the ground.

Hope this helps...
by Bob
Mon Dec 15, 2008 1:18 pm
Forum: Anaerobic Digester
Topic: digester for suburban community
Replies: 3
Views: 13051

Re: digester for suburban community

1) Once we have obtained the gas, how do we purify it to determine how much is methane and how much is CO2? You can scrub the CO2 from the biogas by bubbling it through limewater. H2S can be removed by filtering it through steel wool. That said, I think most people don't bother -- at least not for ...
by Bob
Fri Dec 12, 2008 10:51 am
Forum: Anaerobic Digester
Topic: Biomass Calulator
Replies: 1
Views: 10358

Re: Biomass Calulator

The calculator is based on continuous feed. The inputs are per day.
by Bob
Fri Dec 12, 2008 10:46 am
Forum: Anaerobic Digester
Topic: BIOGAS PLANT INFO
Replies: 1
Views: 10288

Re: BIOGAS PLANT INFO

Hola Fernando,

Are you familiar with the USEPA's Agstar program? They have some design software and a comprehensive handbook free for downloading, that may fit your application better than my smaller scale stuff.

http://www.epa.gov/agstar/resources.html
by Bob
Fri Dec 12, 2008 10:35 am
Forum: Anaerobic Digester
Topic: digester for suburban community
Replies: 3
Views: 13051

Re: digester for suburban community

Hi Drew, I've played with the calculator a little bit but haven't been able to figure it out. It is based on a continuous feed design. The inputs (on the left side) are what would be added on a daily basis. Enter the estimated daily quantity of each feedstock, adjust the mixture till you get an appr...
by Bob
Fri Nov 28, 2008 11:03 am
Forum: Anaerobic Digester
Topic: saving the world and other fun stuff...
Replies: 30
Views: 68674

Re: saving the world and other fun stuff...

Did you see the stuff I added to the R&D Forum?
by Bob
Thu Nov 20, 2008 2:18 pm
Forum: Anaerobic Digester
Topic: saving the world and other fun stuff...
Replies: 30
Views: 68674

Re: saving the world and other fun stuff...

Glad to see you able to pick this back up, Nathan. I'll look forward to seeing what new information you find. And I would love to see it move forward -- like find some funding to build a prototype, test feasibility? For myself, I'm spread a mile wide and an inch deep. Too many projects, just trying ...
by Bob
Wed Nov 19, 2008 12:14 pm
Forum: Anaerobic Digester
Topic: saving the world and other fun stuff...
Replies: 30
Views: 68674

Re: saving the world and other fun stuff...

Good deal!

How goes your world?