Hi Kris,

The sloped bottom has not been a problem in any way. This improved design was made in consultation with the biogas companies, and done specifically so that it will be easy to re-train their existing staff.

Regarding the earthquake damage. I am not directly involved at NBPA any more, so I don't have all the latest updates. To the best of my knowledge surprisingly many biogas plants survived the quake, despite being in heavily affected zones. Most of the plants with actual damage to the concrete dome were those that were still under construction. It seems somehow that those plants that were full of slurry mainly survived. Further, there was some damage to gas-pipes and fittings. However, that is easy to fix. One interesting observation was that many owners of biogas plants did some creative repairs and extensions of the gas pipes from the kitchens of their damaged houses to their temporary shelters.

Regards

Marijn

Thanks for posting this, seems like a logical evolution of the older design. The new sloped bottom is not causing too many construction issues though?

Also: how is the experience now regarding the earthquake? Was it possible to repair some systems without too many issues, or were they often completely destroyed?

Dear colleagues with an interest in Biogas,

Since around 2012, GIZ and the Nepal Biogas Promotion Association have worked on improving the design of the standard model biogas plant build in Nepal. For those familiar with the technology, this is the model that has been promoted in multiple countries under various SNV led schemes.

After a thorough evaluation, I am convinced that the technology is indeed a step forward. Please find the evaluation report here: energyefficiency.gov.np/downloadthis/nib...all_report_final.pdf

This report includes a technical part, which I think will also help people to understand how 'fixed dome" plants function.

The one design improvement that is specifically relevant with regard to sanitation is the addition of a small wall inside the digester. Through this, we have reduced the risk of some material passing through the digester faster than assumed. This helps to improve the pathogen reduction in the slurry.

Regards

Marijn Zandee

PS, dear Susana colleages, please also add this report to the libarary.