Lab Scale Biogas Production from Market Wastes and Dagoretti Slaughterhouse Waste in Kenya (Published)

In this study, fruits and vegetable market wastes were used as substrates in biogas production under psychrophilic, mesophilic and thermophilic conditions. Slaughterhouse waste consisting of blood and diluted rumen fluid mixture was used as inoculum with seven days retention time. Influence of C: N ratios of the unique mixtures of vegetables found in the market were investigated. On average, the vegetable wastes found at the market contained >86% moisture, 5 – 12% volatile solid and 0.46 – 2.06% ash matter on a wet basis. The protein range was between 0.57 – 3.49% with high-fat content being recorded in avocado (Persea americana) wastes at 9.03%.  The highest cumulative biogas was recorded in wastes mixture at 3500ml on seventh day while low biogas yield was registered for wastes with C: N ratios greater than 35:1 like avocado and lower than 10 like coriander and courgette wastes.  The optimum operation pH was in the range of 6.80 – 7.2.It can be concluded that the highest cumulative biogas was generated from fruits/vegetable mixture at 3500ml in mesophillic conditions. This study recommends pH adjustment to 6.8 – 7.2 in market wastes and C: N ratios of 20 – 25 for large scale biogas production of wastes found in the Dagoretti Market.

Keywords: Biogas, inoculum, market wastes, proximate properties

Power Generation Technology with Solar PV-Biogas in Rural Areas of Eastern Java (Published)

Increasing human activity has an impact on energy needs. Electrical energy is the most dominant type of energy used daily. the increase in electricity demand in East Java was due to an increase in industrial activity in several cities in East Java, such as Surabaya, Mojokerto, Sidoarjo. Meanwhile, the electrical energy needs of several rural areas in East Java, such as in Bodowoso, Bangkalan, Sumenep have not been fulfilled due to geographical factors. The solution to fulfillment of electricity in rural areas can utilize the potential of alternative energy, such as solar energy and biogas. The high potential of solar energy and biogas can be used as an energy source for solar PV-biogas hybrid power plants. The aim of the study was to study the application of a solar PV-biogas power plant model in rural areas. The research method of the solar PV-biogas hybrid power plant is carried out in several stages to assess the potential for the application of hybrid power plants in rural areas in eastern Java. The research method uses a 100 Wp solar PV hybrid system model and 1 KW biogas generator set by analyzing the potential of electricity produced on average per day. The results of the study of the analysis of the potential application of solar PV-biogas power plants show the configuration of the power plant model of generating diesel PV-biogas generators produced by solar PV electric power 1.26 KW per day and 1,244 KW biogas generator with a total electrical energy of 2.50 KW / day. Electric energy consumption per family head is an average of 1 KWh / day with the application of a solar PV-biogas hybrid power plant still with a surplus of 1.50 KW of energy, so the model of solar PV-biogas hybrid generator has a good effective and efficient level to be applied in rural Java east

Keywords: Biogas, Electricity generation, Environmentally, Rural, solar PV

Evaluation of Biogas Production from the Digestion and Co-Digestion of Animal Waste, Food Waste and Fruit Waste (Published)

The increased use of fossil fuels for energy consumption has causes environmental problems both locally and globally. The study investigates the anaerobic digestion in the production of biogas a renewable energy from the digestion and co-digestion of three different types of biodegradable wastes (cow dung, fruit waste and food waste) as an alternative for fossil fuels for energy consumption. This was carried out using a 25 Litres capacity plastic keg prototype biogas plant, constructed to investigate the anaerobic digestion in generating biogas. The experiment was batch operated and daily gas yield from the plant was monitored for 30 days. The slurry temperature and pH were also monitored and presented. The digester was charged with these wastes in the ratio of 1:1, of waste to water respectively. The mesophilic temperatures range attained within the testing period were 25 – 28.4 and a slurry temperature range of 24.4 -28.4. The result obtained from the biogas production showed that the co-digestion of cow dung and food waste produced the highest biogas of 164.8%, followed by the co-digestion of the three waste (cow dung, fruit waste and food waste) which has a percentage of 91.0%, co-digestion of cow dung and fruit waste (83.9%), cow dung of 79.8%, food waste of 77.4% and fruit waste of 76.4% within this retention period. During the digestion period, the volume of biogas production and the changes in pH indicate that the pH decreases as the retention period increases. These results showed that co-digestion wastes produce more biogas than when the wastes are ordinarily used for biogas production. The study recommends that biogas is not just a renewable energy source but also an appropriate way of managing waste, having potential to replace fossil fuel.

Keywords: Anaerobic Digestion, Biodegradable Wastes, Biogas, Fossil Fuel, Renewable Energy

Integrated System for Simultaneous Removal of Nitrogen and Phosphorus by Ulva Lactuca and Its Subsequent Utilization for Biogas Production (Published)

Biogas is a combustible mixture of gases produced by microorganisms when livestock manure and other biological wastes are allowed to ferment in the absence of air in closed containers or reactor. This process design proposes an integrated biogas production system that aims to remove nitrogen and phosphorus from polluted seawater using U. lactuca and consequently utilize this as a feedstock for biogas production. Anaerobic digestion is done in the process which accomplished in three stages: (1) hydrolysis of insoluble polymers, (2) fermentation of monomeric breakdown products and (3) fermentation of acetate and hydrogen from volatile fatty acids and (4) generation of methane. The basis of the design is 1,000 metric tons of purified biogas per year which is intended for kitchen stove application. It can promote utilization of endemic U. lactuca for seawater treatment and at the same time provide livelihood to communities and save the aquatic environment from pollution. In addition, utilizing purified biogas as an additional source of fuel can save the dwindling natural gas and oil reserves in the world. This purified biogas can be an alternative to the conventional LPG (liquefied petroleum gas) used for kitchen stoves since their energy value and price are comparable.

Keywords: Anaerobic Digestion, Biogas, Microalgae, Philippines, U. Lactuca

Evaluation of Biogas Production from the Digestion and Co-Digestion of Animal Waste, Food Waste and Fruit Waste (Published)

The increased use of fossil fuels for energy consumption has causes environmental problems both locally and globally. The study investigates the anaerobic digestion in the production of biogas a renewable energy from the digestion and co-digestion of three different types of biodegradable wastes (cow dung, fruit waste and food waste) as an alternative for fossil fuels for energy consumption. This was carried out using a 25 Litres capacity plastic keg prototype biogas plant, constructed to investigate the anaerobic digestion in generating biogas. The experiment was batch operated and daily gas yield from the plant was monitored for 30 days. The slurry temperature and pH were also monitored and presented. The digester was charged with these wastes in the ratio of 1:1, of waste to water respectively. The mesophilic temperatures range attained within the testing period were 25 – 28.4 and a slurry temperature range of 24.4 -28.4 . The result obtained from the biogas production showed that the co-digestion of cow dung and food waste produced the highest biogas of 164.8%, followed by the co-digestion of the three waste (cow dung, fruit waste and food waste) which has a percentage of 91.0%, co-digestion of cow dung and fruit waste (83.9%), cow dung of 79.8%, food waste of 77.4% and fruit waste of 76.4% within this retention period. During the digestion period, the volume of biogas production and the changes in pH indicate that the pH decreases as the retention period increases. These results showed that co-digestion wastes produce more biogas than when the wastes are ordinarily used for biogas production. The study recommends that biogas is not just a renewable energy source but also an appropriate way of managing waste, having potential to replace fossil fuel.

Keywords: Anaerobic Digestion, Biodegradable Wastes, Biogas, Fossil Fuel, Renewable Energy