By Dora Nyirenda, Research Administrator, LUANAR

Wastes being the unusable materials as they are, who would want to do anything with them? But as the saying goes, what can be seen irrelevant to a certain discipline can be relevant to another, for instance, one discipline can think agricultural and municipal wastes do not have any use but here are some scientists, academicians and local people who think that these wastes have the potential to produce energy to help in tackling the issues of climate change.

To validate this, a research project titled ‘Development of sustainable clean cooking facilities to boost resilience to climate change in Malawi’ was funded by the Scottish Government Climate Justice Innovation fund. Different partners namely LUANAR, Abundance worldwide, LEAD, University of Glasgow and Fab engineering partnered with Dr Nader Karimi to work on it. LUANAR’s aim was to conduct surveys on waste availability by studying agricultural and other organic wastes in different parts of the country especially in 6 districts of Nkhotakota and Lilongwe the central part of Malawi, Karonga and Mzimba districts the northern part of Malawi and Machinga specifically in Mbando village and Chikwawa district in the southern part of Malawi in Feb/March/ April of 2020. There after doing the chemical analyses of the wastes.

What an exciting opportunity for LUANAR to be part of the project as it triggered the minds to know more about agricultural and municipal wastes usefulness in production of energy. In Malawi, the general understanding has been that most agricultural wastes have performed poorly in production of biogas and bio-syngas and as such they have mainly been left idle leading to continued use of firewood that leads to deforestation. 

Well not anymore as different solutions are coming up through the use of municipal and agricultural wastes to produce bio-fuels which are then burned in a novel gas cooker. Indeed this will save Mother Malawi from high deforestation rate that it has recorded in the recent years in Africa (Ngwira S & Watanabe T, 2019).

Members from LUANAR conducted surveys in the mentioned districts, some of the common biomass and/ or organic wastes that were found and samples collected were cassava peelings, bean shells, rice husks, bagasse, molasses, maize bran, cow dung, sorghum stems, sorghum fruit, goat droppings and many more. Another waste that was mentioned that some members had responded was plastic wastes; well one would wonder if this is a biomass waste, right? Not strictly speaking though, the origin maybe biomass in fossil form. For some thoughts some might think to study on this and see if these plastics wastes can be useful in generating energy.

Interestingly, some respondents said that most of the crop and livestock wastes are used for crop production as a source of nutrients which is a very good use. Though this is the case, many of them demonstrated that such wastes were not adequately utilized which gives a window of using these wastes in the production of energy.

Bagasse being one such type of wastes that is produced in abundance by the sugar industries as well as residents in sugar growing areas, this waste was found that excess of it is left unused even after the sugar processing companies have burned it to produce electricity. Perhaps, this can be a raw material in areas where it is in excess to produce biogas and bio-syngas.

The waste sample raw materials that were collected were analysed for components that determine suitability of biomass for biogas and bio-syngas production. Carbon: Nitrogen (C: N) ration in the range of 10:30 was used to guide quality aspects related to the intended use. Fortunately, the sampled wastes were within the range that is suitable for biogas production. Most interestingly, all the chemical elements seen as impurities that would reduce the efficiency of the value of the biomass in the production of biogas in the sampled wastes were below the limits of copper (mg/kg) of 10.00, Zinc (mg/kg) 350.00, Nickel (mg/kg) 100 and Chromium (mg/kg) thresholds.

As successful as the surveys and analyses were, Mbando Village in Machinga district was ready to do the trials as the abundant wastes there were rice husks and cow dung. The trials are a success, biogas and bio-syngas are now being produced used for cooking at Mbando.

Laboratory used to analyse biomass wastes