Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious environmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic and environmental challenges. Currently the weed is harvested from the Lake and left in the open to rot and decay leading to loss of aesthetics, land and air pollution. There is therefore need for development of value addition and economic exploitation strategies. The aim of the study is to assess the potential for utilization of the weed as a renewable energy resource for biogas production. Samples were collected from Lake Victoria, pulped and blend with cow dung at a ratio of 3:1 as inoculum. The resultant mixture was mixed with water at a ratio of 1:1 and fed into a 6 m 3 tubular digester. The digester was recharged with 20 kg after every three days. The temperature, pH variations, gas compositions, upgrading and gas yields were studied. The temperature ranged between 22.8˚C-36.6˚C and pH 7.4-8.5. Biogas was found to contain 49%-53% methane (CH4), 30%-33% carbon dioxide (CO2), 5%-6% nitrogen (N2) and traces of hydrogen sulphide (H2S). The biogas was upgraded using solid adsorbents and wet scrubbers increasing the methane content by up to 70%-76%. The upgraded gas was used to power internal combustion engines coupled with an electricity generator and direct heat applications. The study concludes that E. crassipes is a potential feedstock for biogas production especially in areas where it is abundant.
The obstacle to optimal utilization of biogas technology is poor understanding of biogas microbiomes diversities over a wide geographical coverage. We performed random shotgun sequencing on twelve environmental samples. Randomized complete block design was utilized to assign the twelve treatments to four blocks, within eastern and central regions of Kenya. We obtained 42 million paired-end reads that were annotated against sixteen reference databases using two ENVO ontologies, prior to β-diversity studies. We identified 37 phyla, 65 classes and 132 orders. Bacteria dominated and comprised 28 phyla, 42 classes and 92 orders, conveying substrate’s versatility in the treatments. Though, Fungi and Archaea comprised 5 phyla, the Fungi were richer; suggesting the importance of hydrolysis and fermentation in biogas production. High β-diversity within the taxa was largely linked to communities’ metabolic capabilities. Clostridiales and Bacteroidales, the most prevalent guilds, metabolize organic macromolecules. The identified Cytophagales, Alteromonadales, Flavobacteriales, Fusobacteriales, Deferribacterales, Elusimicrobiales, Chlamydiales, Synergistales to mention but few, also catabolize macromolecules into smaller substrates to conserve energy. Furthermore, δ-Proteobacteria, Gloeobacteria and Clostridia affiliates syntrophically regulate PH2 and reduce metal to provide reducing equivalents. Methanomicrobiales and other Methanomicrobia species were the most prevalence Archaea, converting formate, CO2(g), acetate and methylated substrates into CH4(g). Thermococci, Thermoplasmata and Thermoprotei were among the sulfur and other metal reducing Archaea that contributed to redox balancing and other metabolism within treatments. Eukaryotes, mainly fungi were the least abundant guild, comprising largely Ascomycota and Basidiomycota species. Chytridiomycetes, Blastocladiomycetes and Mortierellomycetes were among the rare species, suggesting their metabolic and substrates limitations. Generally, we observed that environmental and treatment perturbations influenced communities’ abundance, β-diversity and reactor performance largely through stochastic effect. Understanding diversity of biogas microbiomes over wide environmental variables and its’ productivity provided insights into better management strategies that ameliorate biochemical limitations to effective biogas production.
The obstacle to optimal utilization of biogas technology is poor understanding of biogas' microbiome diversities over a wide geographical coverage. We performed random shotgun sequencing on twelve environmental samples. Randomized complete block design was utilized to assign the twelve treatments to four blocks, within eastern and central regions of Kenya. We obtained 42 million paired-end reads that were annotated against sixteen reference databases using two ENVO ontologies, prior to β-diversities studies. We identified 37 phyla, 65 classes and 132 orders. Bacteria richness dominated and composed 28 phyla, 42 classes and 92 orders, conveying substrate's versatility in the treatments. Though, fungi and Archaea composed 5 phyla, the fungi were richer; suggesting importance of hydrolysis and fermentation in biogas production. High β-diversity within the taxa was largely linked to communities' metabolic capabilities. Synergistales to mention but few, also catabolized macromolecules into smaller substrates to conserve energy. Furthermore, δ-Proteobacteria, Gloeobacteria and Clostridia affiliates syntrophically regulated PH2 and reduced metal to provide reducing equivalents. Methanomicrobiales and other Methanomicrobia species were the most prevalence Archaea, converting formate, CO2(g), acetate and methylated substrates into CH4(g). Thermococci, Thermoplasmata and Thermoprotei were among the sulfur and other metal reducing Archaea that contributed to redox balancing and other metabolism within treatments. Eukaryotes, mainly fungi were the least abundant guild, conveying largely Ascomycota and Basidiomycota species. Chytridiomycetes, Blastocladiomycetes and Mortierellomycetes were among the rare species, suggesting their metabolic and substrates limitations. Generally, we observed that environmental and treatment perturbations influenced communities' abundance, β-diversity and reactor performance largely through stochastic effect. Understanding diversity of biogas' microbiomes over wide environmental conditions and its productivity provides insights into better management and other effective strategies that ameliorate existing biochemical issues.
The study sought to determine effects of occupational safety and health awareness among on work environment in the Kenyan Kisumu County Water Service industry. The study utilized a descriptive research design. The target population consisted of employees of Kisumu Water and Sewerage Company (KIWASCO) and Lake Victoria South Water Service Board (LVSWSB) working in water treatment works, waste water treatment plants and construction sites. From population of 410, Sample size was determined using standard formula by Fisher (1983). Since the population was <10,000, the formula by Mugenda & Mugenda, (2003) was applied and 81 number of Questionnaires used to obtain primary data finally analyzed using quantitative techniques. A simple random sampling was employed to draw the respondents from each site and selfadministered semi-structured questionnaire was used to acquire data. The data was analyzed using Statistical Package for Social Sciences version 21. Frequencies and percentages were obtained and correlations done using Spearman's correlation coefficients. On the respondents organizations, majority at 57(75%) worked at KIWASCO, 12(15.79%) worked at LVSWSB while the minority at 7(9.21%) worked at GULF. Preponderance of the respondents at 61(80.3%) were males while the least at 15(19.7%) females. Most of the respondents at 28(36.6%) were between 29-39 years of age while the same number of respondents forming the minority at 24(31.6%) were both between 18-28 years and 40-50 years of ages. Preponderance of the respondents at 61(80.3%) had attained college level of education as their highest, 9(11.8%) attained secondary while the minority at 6(7.9%) had attained primary level of education as their highest. On the number of years worked for the organization, majority at 27(35.5%) had worked for 4 years, 24(31.6%) had worked 1 year, 15(19.7%) had worked for 3 years while the least number of respondents at 10 (13.2%) had worked for 2 years for their organization. Preponderance of the respondents at 49(64.5%) stated that water supply was their nature of work, 14(18.4%) stated construction as their nature of work while the minority at 13(17.1%) stated waste water as their nature of work. This research found that awareness of existence of Safety and Health Act of 2007 was to a large extent, mean =3.80, SD=1.200. It was critical for staff to master occupational safety regulations to a large extent, mean= 4.36, SD=0.948, same applying to the importance of knowing and following safe work procedures mean=4.49, SD=0.931. Majority of the respondents were aware of the instructions to follow for safe working practices, mean of 4.38, SD=0.879. The mean of mean was 4.12 denoting that the respondents were aware of occupational safety and health to a large extent. The study analyzed the relationship between staff awareness of occupational safety and health and work environment using Spearman's rho coefficient ,Confidence Level (CL) = 95%, It was established that there is a significant moderate positive relationship between staff awareness...
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