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A comparative study of biogas production from cassava peels treated with different chemicals namely;
potassium hydroxide (KOH, 50% w/v) and locally available potash (“akanwu” 50% w/v) was investigated.
The untreated peels formed the control. The fresh cassava peels were degraded aerobically for 4
months before the chemical treatment, waste stabilization and charging of digesters took place. The
different variants from the treated peels were charged into 50 L metal prototype biodigesters in the ratio
of 2:1 of water to waste. The moisture content of the wastes determined the water to waste ratio. They
were charged as; Cassava peels treated with KOH (CP-K), Cassava peels treated with potash (CP-P) and
untreated cassava peels (CP-U). They were all subjected to anaerobic digestion under a 30 days
retention period and mesophilic temperature range of 25 - 37°C. Results obtained showed that while the
untreated cassava peels had cumulative gas yield of 68.7 ± 1.03 L/Total mass of slurry (TMS), the peels
treated with potash had highest cumulative gas yield of 124.1 ± 2.67 L/TMS, whereas cassava peels
treated with KOH had 111.3 ± 2.44 L/TMS. The flash point for the untreated cassava peels was on the 58th
day, while that for the CP-K and CP-P were 10 and 7 days, respectively. The general results showed that
the biogas yield from cassava peels can be enhanced by chemical treatment. Results further indicated
that locally available potash (“akanwu”) is a better chemical treatment to be employed in the biogas
production of cassava peels.
Key words: Cassava peels, biogas production, cumulative gas yield, onset of gas
Nigeria is richly blessed with various sources of energy both renewable and non- renewable. However, the conventional energy resources such as petroleum, natural gas and coal exploited at commercial quantities are non-renewable and cannot sustain the economy for a long time. There has been a constant period of energy crisis which has manifested in the form of frequent shortages of energy-giving petroleum products and erratic grid electricity supply. This persistent energy problem in the country has disrupted major productive economic activities mostly in the industrial sector where effective operation of machinery and equipment is dependent on energy; artisans like welders, transport industry and households have also been adversely affected.
Climate change due to increasing concentrations of greenhouse gases , namely: carbon dioxide, methane, carbon monoxide, oxides of sulphur, chlorofloro carbons (CFCs) and some oxides of nitrogen, pose threat to human society. The chemicals act by changing the living and working environment to which society has adapted over the generations.
Fermented African mesquite (‘Okpeye’) is a condiment used during food preparations for flavour enhancement, micronutrient and protein enrichment in Nigeria.
Consequently, this condiment is utilized similarly as ‘dawadawa/iru’ (from African locust bean, soybean, etc.) and ‘Ogiri’ from castor oil or fluted pumpkin seeds while preparing foods. However, all the condiments have been processed indigenously using traditional methods that might involve uncontrolled solid substrate fermentation.
Avocado and coconuts are plant fruits readily available during their seasons in Nigeria and fortunately, the fruits are rich sources of oils/fats and phytochemicals which are deposited mainly within the pulp and meat portion of the plant products, respectively. Besides, these fruits are still commercially under-developed.