Recovering biogas and nutrients via novel anaerobic co-digestion of pre-treated water hyacinth for the enhanced biogas production

The present investigation explores the feasibility of generating biogas from water hyacinth (WH) through a pretreatment process. The WH samples were subjected to a high concentration of H2SO4 pretreatment to enhance biogas production. The H2SO4 pretreatment aids in breaking down the lignocellulosic materials found in the WH. Additionally, it helps modify the cellulose, hemicellulose, and lignin, which assists in the anaerobic digestion process. The samples underwent pretreatment with 5% v/v H2SO4 for 60 min. Biogas production was conducted for both untreated and pretreated samples. Furthermore, sewage sludge and cow dung were used as inoculants to promote fermentation in the absence of oxygen. The results of this study demonstrate that the pretreatment of water hyacinth with 5% v/v H2SO4 for 60 min considerably enhances biogas production through the anaerobic co-digestion process. The maximum biogas production was recorded by T. Control-1, with a production rate of 155 mL on the 15th day compared to all other controls. All the pretreated samples showed the highest biogas production on the 15th day, which is comparatively five days earlier than the untreated samples. In terms of CH4 production, the maximum yield was observed between the 25th and 27th days. These findings suggest that water hyacinth is a viable source of biogas production, and the pretreatment method significantly improves biogas yield. This study presents a practical and innovative approach to biogas production from water hyacinth and highlights the potential for further research in this area.

Vibration, acoustic and emission characteristics of the chlorella vulgaris microalgae oil in compression ignition engine to mitigate environmental pollution

The petroleum fuel demand with high price and its exhaustion imposes a pressure to find an alternative. The fossil fuel shortage has been deteriorating over the past few years, because of the rapid increase in population. Many attempts have been made to increase the quality of biofuel with additives. In this paper, two types of nanoparticles such as carbon nanotubes (CNT) and alumina (Al₂O₃) in chlorella microalgae biofuel were analyzed by experimental method. The added CNT and alumina act as a catalyst that induces complete combustion with retarded emissions. In addition to above, the noise and vibration qualities are also measured. A series of test conducted using single cylinders, four stroke, naturally aspirated compression ignition diesel engine was run by using pure diesel and also different fuel blends 'such as B10CNT50A50 Chlorella (Microalgae Biodiesel 10% + Diesel 90% + CNT 50 ppm), B20CNT50A50 (Microalgae Biodiesel 20% + Diesel 80% + CNT 50 ppm + Al₂O₃ 50 ppm) and B30CNT50A50 (Microalgae Biodiesel 30% + Diesel 70% + CNT 50 ppm + Al₂O₃ 50 ppm). At a constant load condition, all experimental tests were conducted at four different speeds such as 1500 rpm, 2000 rpm, 2500 rpm and 3000 rpm. The reference fuel of diesel B0 results was compared with blended fuel. From the results, it has been found that the nano additives of CNT and alumina reduced the greenhouse gas emissions of CO compared to plain diesel. Only considering the blended fuel, as the percentage of biofuel increases, the emission of nitric oxide and carbon dioxide is decreased with significant reduction in the amount of noise and vibration and also the combustion and performance qualities were also improved. The highest benefit in terms of all factors was achieved in the fuel blend of B30A50CNT50 amongst the other blends.