Study on Renewable Biogas Energy Production from Cladodes of Opuntia ficus-indica

Jigar, Elias (2010) Study on Renewable Biogas Energy Production from Cladodes of Opuntia ficus-indica. Masters thesis, Addis Ababa University.

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Abstract

Production of methane-rich biogas through anaerobic digestion of organic materials provides a versatile carrier of renewable energy, as methane can be used in replacement for fossil fuels in both heat and power generation and as a vehicle fuel, thus contributing to mitigate the emissions of greenhouse gases and slowing down the climate change. In this study, the potential of Cladodes, which is plate like section, of Opuntia ficus indica, is evaluated for its potential in biogas production. Five treatments cow dung alone(T1), Cladodes alone(T2), and Cladodes used as feed stock mixed with cattle manure in different combinations (at a level of 50:50(T3) ,25:75(T4) , 75:25(T5) ) allowed to digest anaerobically at ambient temperature in 2.8litre sand jacketed triplicate batch digesters. The amount of biogas and methane produced over the retention time of 66 days for these digesters was compared. The highest total biogas yields were obtained from 75%Cow dung: 25%Cladodes combination (T5) as 14,183 ml followed by T1 as 13670ml ( 0 .022m3/kg) and the lowest was from Cladodes alone as 6,176ml. The percentage of methane gas obtained from the experiment for treatments T1, T2, T3, T4 and T5 were 66.33%,53.16%,63.84%,52.1% and 69% respectively. Among all treatments T5 was found to produce high methane percent of the biogas. Treatments (T1 and T5) that have a C:N ratio within the range of 20-30 found to perform better in biogas yield and methane production than that are not. The experimental findings further showed that the composition of methane for all treatments were within the range of 50 to 70%. As determined in laboratory the physico-chemical characteristics of the Cladodes further revealed the suitability of the substrate for biogas production and if suitable materials for co-digestion, such as manure, are not available, Cladodes can be digested alone. Statistical test for the mean difference of dependable variable pH of treatments except between T3 and T5 varies significantly at 0.05 level. The result also showed that the biogas and methane content of the gas produced by T5 vary significantly at 0.05 level except with T1and T3. Finally, environmental, slurry and foreign currency benefits have been realized through fuel replacement value of the biogas produced by the five treatments.

Item Type:	Thesis (Masters)
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences Q Science > QH Natural history > QH301 Biology Q Science > QK Botany T Technology > TD Environmental technology. Sanitary engineering
Divisions:	Africana
Depositing User:	Selom Ghislain
Date Deposited:	25 May 2018 12:49
Last Modified:	25 May 2018 12:49
URI:	http://thesisbank.jhia.ac.ke/id/eprint/4124

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