Dear JKM,

Thanks for analyzing this.

I think the option of PET bottle columns filled with cement would be very stable against collapse, especially if steel rebar (or similar) is placed in the center of each column, which would serve for compacting the fresh cement and remain there for support. My concept is put horizontal strips of PET folded lengthwise (which has great tensile strength) or plastic rope (which would be easier and still presumably resistant to H2S) threaded through holes melted into the columns of PET bottles, to hold them together. These holes may need to be sealed with tar or something. So the cement and steel would be protected inside the PET.

The idea of burning in situ to convert clay walls into ceramic is very interesting in places where the water table is very low in the ground, for example in the Andes, where one can readily dig into the abundant compressed volcanic ash. The burning could be done progressively after each meter of digging. Are there any instructions for this available on the internet?

This is just brainstorming, so if I am wrong on any point, please do not hesitate to tell me.

Best wishes,
Chris Canaday

Ahh, ok I misunderstood your idea, cement filled bottle columns might be strong enough. Horizontal connection would be probably the main design dificulty however.

Concerning the insitu fired clay... there isn't much and I just recently came across this idea. This document explains the process on page 31pp:
www.friendsofkitui.com/images/PDFs/TR28-...nwater%20STORAGE.pdf
However only for small (1.5m3) water tanks. Especially deeper holes would probably have to be artificially ventilated to have sufficient oxigen for the fire.

I would think that making shingles from PET bottles is a lot of work and if they are on the inside, they need to be fixed (held) in place in a very durable manner. It would be faster to line the inside of the reactor with butyl foil, ofcourse far more expensive, but smooth and very durable.
You can use the PET bottles as cavity wall, either having masonry on both sides or cast them centrally inside a concrete wall. This will reduce the amount of concrete and increases the wall stiffness. In addition it will improve the thermal insulation of the wall, making the reactor work at higher temperatures, which may be a benefit in colder climate zones/periods. For reinforcing the interior or exterior sides, glassfibre webbing (e.g. Vitrulan) would not be affected by the acids, but they have to be covered with cement mortar. When you build the installation it has to last 30 years, so economising on the building materials by using untested solutions is seldom a good idea. That is why I like to hear of any dyrale results with PET lining.

Dear Chris and other authors:

You will likely not hear anything about building a reactor with PET bottles...., but we do have a course in anaerobic wastewater treatment coming up early March, with design and calculation of UASBs as an important aspect. It is a one week course, also the starting week of the 3 week module on Resource Oriented Wastewater Treatment and Sanitation. Teachers are prof. Jules van Lier, one of the successors (and former students) of Prof. Gatze Lettinga, and Prof. Carlos Chernicharo, who has a sea of expertise on UASBs in Brasil.

For this year the scholarship application is closed but for next year you can apply now.
Registration for this year is still open!

More information can be found on www.unesco-ihe.org/Education/Non-degree-...tment-and-Sanitation
and in the attached brochure. Oh for some reason the PDF does not attach.. I can send it via email upon request.

Please do not consider this hidden commercial; if it's interesting for you then it is; if not then not.

Best regards,
Mariska.

Dear Chris Canaday,

How fare are you with your possible UASBs?
Would be nice to here more from you on your subject in question mark.

Regards,

Detlef SCHWAGER