The microorganisms that are best at producing hydrogen and biogas are also sensitive, for example, to the smell of fruit. That smell is even toxic to them. For that reason, the production of hydrogen and biogas from fruit waste is normally not very efficient. However, if the microorganisms are protected by membranes, they become many times more efficient.
“As everyone knows, the world is facing major challenges right now when it comes to dealing with climate change”, said Julius Gbenga Akinbomi. “In Nigeria, my native country, most of the population don't have electricity. Added to that, we have problems with environmental degradation from waste that is burned or discarded in watercourses or landfills. Other people use dangerous generators indoors, with the risk of carbon monoxide poisoning. At the same time, there is plenty of waste that is not being used. I want to create efficient biogas production plants that take advantage of the waste and provide people with electricity. My next step is to present my findings to the Government so we can make plans to start building the plants!”
Focused on fruit waste
He talks enthusiastically about how biogas production plants can be introduced at a municipal level and also for units as small as individual households. They produce either hydrogen or methane. These gases are used as fuel for vehicles, to power cookers or to supply electricity. An airtight vessel with an opening for putting in the organic waste and an opening for the gas is basically all you need.
“Put the waste in the container and wait for about a week and you will notice that gas is produced. In my research I have focused on fruit waste because it is so common and widely available. But the thing with the smell of fruit means that the microorganisms are destroyed and don't produce as much as they could. In my first experiments with hydrogen production from fruit waste without the use of membranes I only achieved 30 per cent of the gas production that is theoretically possible.
With the aid of small bags of polyvinylidene difluoride (PVDF) membrane, which feel a bit like plasticised paper, the smell of fruit can be kept away from the microorganisms. This is because the PVDF attracts water and water repels the smell of fruit.
"I have tested many different varieties of fruit waste and combinations of pressure, temperature and pH. According to my measurements, the membrane can protect the gas production and make it much more efficient. We can produce both hydrogen and methane.”
Nigeria is a country facing tremendous challenges
It is enough for a small proportion of the microorganisms to be protected in the membrane for them to act as catalysts and make the whole process much more efficient. The idea is for hydrogen to be able to be used in the near future as fuel for vehicles. Also, production of composites such as ammonia, synthesis gas (carbon monoxide and hydrogen) and hythane (natural gas with hydrogen mixed in) will be carried out on a large scale, while methane can already be distributed for both small- and large-scale use.
After the public defence of his thesis, Julius Gbenga Akinbomi will return to Nigeria to continue his research and work on a proposal for the Government on how his findings can be used. He also has ideas on how knowledge of the methods can be disseminated in this vast, densely-populated country.
“We must use our natural resources in a sustainable and sensible way”, he says. This method does not contribute to increasing the greenhouse effect, but instead improves the environment. Of course it benefits everyone in the world, but it is especially important for a country like Nigeria, that faces such tremendous challenges such as a worsening energy crisis and inefficient waste disposal. Now it will be possible to dispose of waste and at the same time gain access to cheap electricity!
Thesis: “Fermentative hydrogen and methane productions using membrane reactors”
By the postgraduate student: Julius Gbenga Akinbomi at the University of Borås
Supervisor: Mohammad Taherzadeh, Professor at the University of Borås
Public defence of the thesis: 28 October, at 10 am, University of Borås, Allégatan 1, room E310.
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