Comparative Study on Biogas Production Using Cowdung, Eucalyptus (Eucalyptus Camaldulensis. Dehnh) and Mixture Wastes

Abstract

Eucalyptus camaldulensis. Dehnh trees are widely grown in most forest reserves in Nigeria especially in savanna agro-ecological zone for paper and construction industries. The waste (leave litters) generated during wood processing are often wasted. Therefore, comparative study was carried out to compare biogas production using Cow dung, Eucalyptus waste and mixture of the two. Rubber buckets (10 liters) were used as digester, slurry was prepared (3kg dung: 3000ml water, 1kg eucalyptus: 5000ml water and 2kg mixture: 4000ml water), digesters were fed in triplicates and subjected to anaerobic digestion for 6 weeks. Biogas was measured using water displacement method. Bacterial count was monitored by spread plating method using blood agar at 106 dilution factor, incubated anaerobically and viewed using microscope. Cow dung recorded highest volume of biogas 3136cm3 at week 3, eucalyptus 2383cm3 at
week 4 and then mixture 2259cm3 at week 3. Highest bacterial counts were 367x106 cfu/ml at week 3, 352x106 cfu/ml at week 4 and 383x106 cfu/ml at week 3 for cow dung, eucalyptus and mixture respectively. The data obtained were subjected to Analysis of Variance (ANOVA) using Statistical software (SAS), biogas yield and Bacterial count were significant at (P<0.05). Caloric values and percentage of some gases were also determined for biogas produced using NDIR Gas analyzer, methane content and caloric values were (53.35%) & (249.58 KJ/m3), (34.79%) & (125.98 KJ/m3) and (34.58%) & (124.60 KJ/m3) for eucalyptus, mixture and cow dung respectively. This research has proven the potentiality of biogas from the samples especially eucalyptus which recorded highest methane contents.