Biogas in Zanzibar

Introduction of biogas technology in Zanzibar

DANTAN has together with engineer Jan Mallan been working with a biogas concept for more than 5 years. It started from an interest in developing a biogas system that would fulfill the demands of an average African family for cooking and light. We wanted to focus on the family as the target group and set out to develop a new type of system that would not require highly skilled labour to install.

The DANTAN / SUPERGAS system is a two-chamber system with a hydraulic valve. It consists of an inlet, two water tanks, connecting underground pipes, outlet, hydraulic valve, a gasometer, condensation collector and connecting gas pipes. The system has no moving mechanical parts. It uses only a minimum of water and slurry can be unloaded from the digester while the system is in use. The hydraulic valve secures automatic stirring. The stirring mixes old and new organic material thus increasing the gas production.

The first test of this new design was carried out by SUPERFLEX in collaboration with the Tanzanian NGO, Surude. This system was made of a soft PVC membrane. The system was functioning for a couple of years, but it was learned that the soft PVC was too fragile. Rats and chicken were perforating the PVC.
After this, a test was carried out in Thailand where the SUPERGAS installation was made from already existing PE water tanks that were procured locally. These tanks proved to be much more durable and easy to work with. Every installation was made from what was available locally with the help from a local technician.

DANTAN is now working in Zanzibar together with a local NGO, ZALWEDA,- to copy and modify the installation in Thailand to fit the local context and conditions. The project in Zanzibar has been underway for 4 years involving installation of several plants, know-how transfer, training and setting up a micro-credit programme. The micro-credit programme is now implemented and it allows loans of up to 60 % of the total price can be obtained, with a repayment period of 36 month.

The idea in Zanzibar was to install pilot plants together with local technicians and monitor and adjust them over a longer period of time. Now an additional 6 plants are installed supervised by us.

When the biogas concept is mature it is important for us to make the technology available through an open source strategy for small entrepreneurs and the end-user who will benefit from our initial adaptation of the design to East Africa. It is DANTAN's vision that making the technology open source will provide greater exposure for the concept and thereby greater impact than it would otherwise.

November 2009, Jesper Kirknæs