Evaluation of Biogas Yield of Selected Ratios of Cattle,Swine, and Poultry Wastes

Production of biogas from animal wastes could lessen the problems of energy shortage and indiscriminate animal waste disposal. A study of anaerobic digestion of selected ratios of cattle, swine, and poultry wastes was carried out to evaluate their biogas yields. Cattle (C), swine (S), and poultry (P) wastes were mixed as C:S:P in the following ratios: 1:0:0 (control), 1:0:1, 4:1:3, 2:1:1, 4:3:1, and 1:1:0 by mass to obtain six samples of of 0.4 kg each, referred to as samples 1 to 6 respectively. A quantity (0.1 kg) of inoculum (obtained by pre-fermenting equal masses of poultry waste and water for 50 days under anaerobic condition) and 0.5 kg of water were added to each of the samples. The resulting slurries were digested in triplicates for 30 days in 1.3 L laboratory-scale anaerobic digesters. The volume of biogas produced was obtained by downward displacement of water in a measuring cylinder. The cumulative biogas yields of samples 1 to 6 were 332.5, 497.5, 487.5, 467.5, 457.5, and 430.0 cm³/kg slurry respectively. The cumulative biogas yields of samples 2 and 3 were significantly (p < 0.05) higher than those of the other samples but not significantly (p > 0.05) different from each other. However, the cumulative biogas yield of sample 1 was significantly (p < 0.05) lower than those of the other samples. The study revealed that a blend of equal masses of cattle and poultry wastes is optimum for biogas production.     

Effect of electronic waste on E. coli genomic integrity: a possible role for metal induced carcinogenesis

Electronic waste (e-waste) poses a major public health threat for developing countries’ populations. The hazards of e-waste are exacerbated by crude recycling methods. In this study, the presence of metals in e-waste samples obtained from Lagos, Nigeria, was assessed using atomic absorption spectrometry. The effect of e-waste on Escherichia coli (E. coli) PQ-37 genomic integrity was evaluated using the SOS chromotest. The means of metal concentrations in the evaluated samples were 16 (cadmium), 7.3 (nickel), 11 (chromium), 20 (lead), 3100 (iron), 90 (zinc), and 2000 (copper) μg_L^?1. Damage to E. coli deoxyribonucleic acid (DNA) increased proportionally to the metal concentrations. Significant amounts of DNA damaging agents from inadequately processed e-waste are present in the studied environment, which will have implications for adverse effects on public and ecological health. Existing policies against dumping of toxic materials in susceptible communities should be enforced.     

Between the rich and poor: exposure and adaptation to heat stress across two urban neighbourhoods in Nigeria

Environment, Development and Sustainability - With heat stress as a notable climate-related challenge in Africa, the need to limit heat exposure and enhance adaptation becomes important....