Design and development of a bio-digester for production of biogas from dual waste

Abstract

Purpose A novel cost-effective bio-digester was explored to convert biological waste into useful clean energy. The bioreactor was aimed to anaerobically digest locally sourced cow dung and chicken droppings. Design/methodology/approach The design consideration is a batch horizontal 267 L digester made from cast iron with centrally positioned four-impeller shaft to enhance mixing. The system operated with a retention time of 63 days and a substrate (cow dung and poultry waste) ratio of 1:2 and water substrate ratio of 1:0.5 in the gasholder system. The purification, compression and performance evaluation of the generated biogas were also conducted. Findings The total volume of gas produced for each substrate compositions designed over 14 days ranges between 49.34 and 52.91 mL/day. The optimal value of 52.45 ml using cow dung and poultry waste (w/w) 20:80 was obtained. The average ambient temperatures during the study were within the mesophilic range of 20-40°C. The pH values were stable and always in the optimal range of 6.5-8.0. The reductions in moisture content, ash content, total solids and volatile solids were from 80.50-0.20 per cent, 39.60-14 per cent, 18.50-5.90 per cent and 11.60-4.90 per cent, respectively. Originality/value The developed digester is cost-effective and would help minimize solid waste disposal. The estimated methane contents of the gas from cow dung and chicken waste after scrubbing were found to be 71.95 per cent and could be harnessed in solving the energy crisis in the developing nations.

Development of Biofertilizer from Locally Sourced Materials

“…While the change in pH from acidic to neutral recorded from the sixth day is due to the conversion of volatile fatty acid produced by acid formers to methane by bacteria (methanogens), these bacteria are responsible for the production of methane. Furthermore, a significant increase in biogas production was observed on day sixth day, this is similar to studies conducted by (Eze, J. and Onwuka, 2007; Harikishan, S. and Sung, 2003; Okwu et al, 2020). Moreover, the fluctuation in pH between 6 and 7.5 is a result of Volatile Fatty Acid (VFA) concentration, and the ability of methanogens to convert them into methane.…”

“…Moreover, the decrease observed in the volatile matter and total Solids (TS) after digestion is a result of the effectiveness of the system and the retention time (37 days) together with the level of nitrogen content in the poultry waste. This is similar to (Okwu et al, 2020). Additionally, the decrease in ash content shows that carbon is been consumed.…”

Environmentally Friendly Energy-Based Park for Carbon-Neutral at Universitas Pertamina

“…The next alternative is a biodigester, a method that can process organic waste into biogas. In this method, the existing waste is put into a biodigester to be processed into biogas by biological conversion [26][27][28] [29]. The calculation of organic waste into biogas is carried out where 1 MT of organic waste is equivalent to 403 kWh [9].…”

Biogas Production: A Comparative Study of Chicken Droppings (Poultry Waste) and Banana Peels as the Gas Source

“…The non-renewability and depletion of conventional fossil fuel sources are other concerns for sustainable energy generation [4]. Research shows biogas can be generated from chicken droppings [5][6]. Chicken droppings are always stored in poultry farms for days or even months before utilizing it as fertilizers or other use.…”