Development of bio-gas using crop wastes and pig dung

Abstract

Effect of crop wastes on the production of pig dung bio-gas was investigated. Beans husks, peels of cassava, plantain and yam were processed with fresh dung of pig. Bacterial and fungal counts in the digesting materials ranged from 1.5 x 1011cfu/ml to 3.5 x 1011cfu/ml and 0.8 x 1011sfu/ml to 1.4 x1011sfu/ml respectively.Atotal of sixteen (16) bacterial and six (6) fungal species were isolated from the digesting materials. The bacteria identified include Clostridium tyrobutyricum, Escherichia coli, Klebsiella pneumoniae, Proteus morganii, Clostridium sphenoides, Bacillus subtilis, Bacillus licheniformis, Bacillus laterospores, Micrococcus roseus, Leuconostoc mesentenroides, Acetobacter orleanensis, Methanobacillus, Flavobacterium ferrugineum Enterobacter aerogenes, Streptococcus pyogenes, Lactobacillus leichmannii and fungi identified were
Mucor mucedo, Rhizopus nigricans, Aspergillus flavus, Aspergillus niger, Cladosporum spp and Saccharomyces cerevisiae. The pH of the digesting materials was between 5.20 and 7.10, the pH decreased and increased as the digestion period progressed. Temperature ranged from 260C to 340C. The result of the chemical analysis of the pig dung bio-gas was 70.55% for
CH4, 13.17% forNH3, 6.75% forH2S and 5.87% for CO2 and traces of other unknown gases which were found to be low. It was observed that the quantity of the crop wastes and pig dung fed into the digester had a significant effect on the CH4 and CO2 gas produced.