An experimental study on Bio-gas production by anaerobic digestion of RiceMill Wastewater (RMW)

<p>With the rising interest for sustainable power source and ecological security, anaerobic digestion of biogas technology has attracted considerable attention within the scientific researchers. This paper proposes a new research achievement on biogas production from Rice Mill Wastewater (RMW) with the utilization of anaerobic digester. An anaerobic digester is maintained with RMW and distillery anaerobic sludge at mesophilic temperature condition for 15 days as stabilization mode. After attaining stabilization stage, studies continued to examine the effect of Organic Loading Rate (OLR) and Hydraulic Retention Time (HRT) on the mesophilic anaerobic digestion of RMW. The OLR of the anaerobic reactor increased stepwise from 0.25 to 3.91 Kg COD/m3/dayand HRT ranged from 1 to 32.0 days. The total chemical oxygen demand (TCOD) utilized was higher than 75% and the CH4 percentage of the biogas was 62.00-63.00% for the OLRs studied. The efficient working volume of the digester is preserved as 25% of distillery anaerobic sludge and 75% of rice mill wastewater, loaded at Mesophilic temperature conditions for study purpose. By changing the conditions of OLR and HRT, biogas production, methane yield and percentage of COD reduction is examined. An anaerobic sludge is utilized as a seeding material to biodegrade the organic pollutants present in the wastewater. It will enhance the biological treatment of effluent with anaerobic sludge in a continuous mode of activity.The result showed that the proposed analysis obtains more biogas production with reduced COD when compared with existing approaches.</p>

Numerical investigation of energy losses in the environment for mesophilic mode of fermentationent for mesophilic mode of fermentation

The article is devoted to the study of energy losses of a biogas reactor into the environment during the fermentation of biomass in the mesophilic temperature regime. The article considers the influence of the presence of the insulating layer of the biogas reactor and the ambient temperature on the amount of energy losses and the required energy to recover these losses depending on the volume of the biogas reactor. The developed mathematical model allows to estimate the intensity of energy losses to the environment taking into account the amount of contamination of the inner wall of the biogas reactor, ambient temperature, average wind speed for the reactor location, surface area of the biogas reactor and its volume, material from which the biogas reactor is made, insulating layer and its material, mode of movement and frequency of biomass mixing. The following assumptions have been made for numerical studies: biomass fermentation takes place in the mesophilic temperature regime , biogas reactors with a volume of 50 to 200 liters, at ambient temperatures from to . It has been established that the heat loss to the environment for different volumes of biogas reactors, regardless of the ambient temperature and the presence or absence of an insulating layer, is not linear. Numerical research has shown that the use of an insulating layer of mineral wool with a thickness of 100 mm, depending on the volume of the biogas reactor and ambient temperature, reduces the amount of energy required to maintain the thermal regime by 55-63 times. Taking into account the amount of losses at the stage of design and manufacture of biogas reactors will reduce energy costs to maintain the required temperature, thereby increasing the profitability of the biogas plant.

Comparative Analysis of Biogas and Methane Yields from Different Sizes of Groundnut Shell in a Batch Reactor at Mesophilic Temperature

Aim: To study the effects of different sizes of groundnut shell on biogas and methane yields using batch reactor at mesophilic temperature. Place and Duration of Study: The laboratory experiment was carried out at the Laboratory of the Department of Agricultural Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria, between August and October, 2018. Methodology: Batch experiment was set up for a period of 35 days with substrate reduced to 2, 4 and 6 mm sizes. The digesters were subjected to anaerobic digestion at mesophilic condition and the gas produced were collected with graduated gas sampling bottles dipped in measuring cylinders already filled with red liquid. The total gas produced was analyzed using gas analyzer to give the percentage composition of the gas components and Enwuff equation was used to calculate the biogas and methane yields of organic dry matter and fresh mass of the samples. Results: The total gas volume of 482.5, 605.0 and 732.5 ml were recorded for the sizes 2, 4 and 6 mm respectively. The organic dry matter biogas yields were 357.1, 514.31 and 324.5 lNkg-1oDM for treatment 2, 4 and 6 mm respectively; while organic dry matter methane produced were 222.41, 298.41 and 211.31 CH4kg-1oDM for 2, 4 and 6 mm, respectively. The fresh mass biogas yields were 147.6, 180.7 and 177.3 lNkg-1FM and fresh mass methane yield were 919, 104.8 and 115.4 lNCH4 kg-1FM for 2, 4 and 6 mm, respectively. Conclusion: Considering the yields recorded, the experiment shows that size reduction had effect on biogas yields and it is an important factor to be considered in biogas production. Treatment with particle size 4 mm seems to be the ideal size when considered the yields in terms of organic dry matter and fresh mass basis.