Search found 302 matches

by Bob
Sat Jan 05, 2008 6:53 pm
Forum: Anaerobic Digester
Topic: digester design and costs estimates
Replies: 1
Views: 11230

Hi Tom, Sounds like a great project. Did you plug the feedstocks into the online calculator ? It can give you a rough estimate of overall tank volume required. Yes, you should be able to scale up the prototype plans, but that may not be the best idea. With multiple tanks like you have, I think I'd c...
by Bob
Sat Jan 05, 2008 5:56 pm
Forum: Anaerobic Digester
Topic: two-stage digester with corrugated pipe
Replies: 1
Views: 11334

Interesting ideas Seth,

By 'corrugated piping' do you mean the 3" - 4" diameter stuff that comes in a flexible coil? Or the larger diameter rigid pipe? If you could sketch what you have in mind, I could offer some ideas -- for what its worth...
by Bob
Fri Nov 30, 2007 9:31 am
Forum: Anaerobic Digester
Topic: carbon to nitogen ratio of feedstock
Replies: 1
Views: 10644

Hi,

From everything I've read, 30:1 is an ideal C/N ratio for both aerobic and anaerobic bacteria.
by Bob
Fri Nov 23, 2007 8:36 pm
Forum: Anaerobic Digester
Topic: anaerobic digestion of poultry waste
Replies: 1
Views: 10907

Hi John, Your operation is far bigger than the small scale systems I have any experience with, or that are described here. That said, the data I use in my online calculator is from Other Homes and Garbage by Leckie, Masters & Young. More information is available here . Scroll down to the table near ...
by Bob
Tue Nov 20, 2007 3:48 pm
Forum: Anaerobic Digester
Topic: New and looking around for info
Replies: 1
Views: 10974

Hi Dunappy,

Welcome.

A good place to start would be with this online calculator. It can give you a rough idea of the size of your digester and an estimate of gas production.
by Bob
Mon Nov 12, 2007 1:14 pm
Forum: Anaerobic Digester
Topic: Piedmont Biofuels Digester Design
Replies: 10
Views: 24415

That's it, girl Mark. I've used a 30 gal drum inverted inside a 55 gallon drum, with three vertical 1-1/2" PVC pipe guides bolted to the 55 gal drum to keep the inverted drum straight as it rises & falls. The gas pressure under the weighted cover is a function of the weight of the cover and its hori...
by Bob
Sun Nov 11, 2007 12:27 pm
Forum: Anaerobic Digester
Topic: Piedmont Biofuels Digester Design
Replies: 10
Views: 24415

There are various so-called 'hybrid' designs in which there are multiple batch-fed 'first stages', which generate the "food" (volatile acids) for the methanogens in the biogas digester. And only the biogas digester needs to be carefully controlled for pH and temp -- a cost (and complexity) savings....
by Bob
Thu Nov 08, 2007 6:19 pm
Forum: Anaerobic Digester
Topic: Piedmont Biofuels Digester Design
Replies: 10
Views: 24415

Its interesting to hear that the acidogens don't require as much heat. At what temperatures do they work most effectively and what range of temperature can they survive? This page provides an explanation. Basically they consist of a large and diverse group of hardier creatures. They can survive a w...
by Bob
Thu Nov 08, 2007 12:48 pm
Forum: Anaerobic Digester
Topic: Piedmont Biofuels Digester Design
Replies: 10
Views: 24415

We're building wooden boxes to house 5/8" aluminum coils that will be packed in with clay (here in north carolina we have plenty of metal rich red clay) that will interface with the plastic tanks. Are they sized based on the heat loss calculations above? Or flying by 'seat of the pants'? How will t...
by Bob
Mon Nov 05, 2007 10:16 am
Forum: Anaerobic Digester
Topic: Piedmont Biofuels Digester Design
Replies: 10
Views: 24415

Glad to see you here, girl Mark.

I hope you find as much value here as I found on your forum.
:)
by Bob
Thu Oct 25, 2007 12:03 pm
Forum: Anaerobic Digester
Topic: Piedmont Biofuels Digester Design
Replies: 10
Views: 24415

Hi scumeye, Wow. I'm honored, girlmark. Nice to see you here. I came across your biodiesel forum a couple of years ago, when I was involved with a community food production project for rural Alaska and was very impressed. Some of the best d-i-y biodiesel information available. (The project involved ...
by Bob
Tue Oct 02, 2007 9:15 am
Forum: General Catchall
Topic: fledgling converting a bus
Replies: 1
Views: 11582

Hi Rosa, You and your dog can't generate enough waste to run a fridge, but you and your dog plus a bunch of leaves, yard clippings and/or vegetable scraps, etc. possibly could. On the other hand, building operating and maintaining such a digester might also be more costly than just buying electricit...
by Bob
Wed Aug 29, 2007 2:55 pm
Forum: Anaerobic Digester
Topic: AD using diaposable diapers
Replies: 3
Views: 14169

Yes. In my opinion, disposable diapers are just another example of our dominant culture's "smart but not wise" thinking. Human waste does not belong in landfills, and the plastic and artificial fiber in these diapers does not belong in our sewers or wastewater treatment plants. The best solution to ...
by Bob
Sun Aug 26, 2007 9:10 am
Forum: Anaerobic Digester
Topic: AD using diaposable diapers
Replies: 3
Views: 14169

I don't know of any research done on it, Paul.

Lacking that, all I can suggest is shredding some and testing them in a test digester.
by Bob
Sun Aug 05, 2007 8:55 am
Forum: Composting Toilet
Topic: Solviva's flush toilet composting filter
Replies: 3
Views: 15032

Most interesting product.

I'm impressed not only with the idea, but with the marketing. Using humus which "turns the problem (the waste) into the solution (the humus to filter and clean the wastewater)" is rather similar to the way I use sludge as a filter media in my graywater treatment unit.
by Bob
Sat Jul 21, 2007 8:47 am
Forum: Biofilter
Topic: BioFilter Treatment Questions
Replies: 20
Views: 55869

I think we use an average 180l (~50 gal) / day /person, yet the norms specify a minimum of 300 liter. That sounds pretty typical. The need to design for worst case and safety factor is discussed in the proposal. If a full backup system is in place (a drain field), then the reclamation system doesn'...
by Bob
Sat Jul 21, 2007 8:38 am
Forum: Composting Toilet
Topic: Solviva's flush toilet composting filter
Replies: 3
Views: 15032

Very interesting.

At first glance (without having read all the details) it looks like a greatly upscaled version of Jenkins' humanure buckets. Lots of carbon!

As always, the devil is in the details. I need to read her book!
by Bob
Thu Jul 19, 2007 8:18 am
Forum: Biofilter
Topic: BioFilter Treatment Questions
Replies: 20
Views: 55869

Does the system described in the document I pointed to look like a feasible possibility?

Users would have to install regular (closed) septic tanks, then pump settled effluent from them into this unit for further treatment and reuse.
by Bob
Wed Jul 18, 2007 9:57 am
Forum: Biofilter
Topic: BioFilter Treatment Questions
Replies: 20
Views: 55869

what is a natural step for an ecological-conscious person might be a too large leap for humankind, or at least for most people in my country Yes, very true. We in the west have such a long history of putting our shit in our drinking water that it is now taken as a given. To suggest that if we just ...
by Bob
Mon Jul 16, 2007 10:55 am
Forum: Biofilter
Topic: BioFilter Treatment Questions
Replies: 20
Views: 55869

what is the role of pvc ribbons (those you clean on the video)? Wouldnt the dissolved oxigen flowing out of trickle filter be consumed anyway in the sludge at the bottom of the 2nd tank? Good questions, cezar, and not ones I'm sure I have a good answer to. The added media was a bit of an afterthoug...