Evaluation of prospects and barriers of biogas produced from livestock waste towards sustainable developmentand adaptation to climate change in Nghe An province, Viet Nam

The livestock sector is one of the fastest growing agricultural subsectors in Viet Nam, resulting in growing demand to sustainably dispose or re-use livestock waste. This research examined the current adoption of biogas digestion of livestock waste treatment at household farms in order to provide insights for policy towards effective implementation. A questionnaire survey was conducted in September 2019, with the participation of 120 livestock owners in Nghe An province, which focussed on accessing their perspectives on biogas and examination of factors impacting their decisions to utilize this technology. Most respondents determined biogas to be an attractive solution for improving the environment. However, several factors limited the development of biogas installation, including technical and financial barriers, awareness and capacity limitations, and financial support as the most significant of these. Government support and policies that encourage household biogas utilization as a sustainable energy source to combat climate change is recommended.

A CRITICAL REVIEW ON THE EFFECT OF FEED TO INOCULUM RATIO ON BIOGAS DIGESTION

This paper primarily focuses on the effect of feed to inoculum ratio on biogas digestion; and outlines the various feeds, inoculums, and synergistic effects of the combination of inoculums by referring to the literature. The Start-up of an anaerobic digestion system is highly critical and pivotal for the successful operation of an anaerobic digester. For this purpose, a certain amount of inoculum is added to the digester along with the substrate to provide the necessary microorganisms to initiate the digestion process. The ratio and the type of inoculum used substantially affect the rate of biodegradation and the lag time. The degradation of substrate depends on the concentration of microorganisms. When food waste was considered as the feed it was found that factors such as waste oil content, the addition of alkaline buffer, particle size, organic loading rate had a considerable effect on the feed to inoculum ratio. Studies considering some other feeds such as animal by products from piggery slaughterhouses, poultry slaughterhouse wastes, agro-industrial waste, anaerobically digested sludge obtained from municipal wastewater, and dewatered digestate cake were also compared. Hence, the objective of this study is to offer an integrated view of the appropriate feed and the inoculum under the effect of various other essential parameters. The major performance indicators from this study were found to be particle size of inoculum, organic loading rate, the addition of alkaline buffer, F/I ratio, and structure of inoculum

A STUDY ON SWINE WASTEWATER TREATMENT AFTER BIOGAS DIGESTION USING ACTINASTRUM SP.

Hiện nay tảo đã và đang đươc̣ chú trọng nghiên cứu để ứng dụng vào trong các lĩnh vực khác nhau. Với mong muốn góp phần vào ứng dụng công nghệ vi sinh giảm thiểu ô nhiễm trong các nguồn nước thải ô nhiễm hữu cơ... phù hợp vớ i tı̀nh hı̀nh Việt Nam, nghiên cứu này tiến hành ứng dụng tảo Actinastrum sp. nhằm xử lí nitơ, photpho trong nước thải chăn nuôi heo sau hầm biogas. Kết quả thực nghiệm cho thấy chi tảo này có khả năng xử lí tốt nước thải chăn nuôi, đáp ứng các tiêu chuẩn theo Quy định Quốc gia QCVN 62-MT:2016/BTNMT với hiệu suất loại bỏ COD và TN tối đa lần lượt là 84,62% và 81,88%, khi được bổ sung mật độ tảo 2,5×10^6 tế bào/mL.

Biogas Synthesis as Means of Solid Waste Management in Kampala, Uganda

Cattle dung, cooked food waste, and chicken droppings mixed with coffee husks have been used separately and also as mixtures to form anaerobic digestion slurries in a bid to treat to degrade the organic fractions of these wastes and recycle the bio-fertilizer after recovering biogas. Single and mixed substrate slurries evolved significant quantities of methane within 27days together with reduced mass of soil conditioner. The volume of biogas formed in cogeneration mixtures were higher than for single substrate digestion due to the C/N ratio shifting to near 30:1 as a result of mixing. So degradation of organic pollutants was higher in mixed substrate digestion mixtures. Our study yielded average volumes ranging from 315 to 435+ 5.65.mL/L which was in agreement with what is in literature. Digestion of cattle dung, cooked waste foods, and droppings of chicken and mixed substrate slurries using sludge inoculums was very effective in degrading solid waste from homes, thus detoxifying it to bio-fertilizers. Although both single and mixed substrate digestion of waste yielded high enough volumes of biogas; digestion of slurry of mixed organic solid waste substrates is better method of waste management. Digestion of garbage from Kampala should be tested at macro levels at both ambient and mesophilic temperatures. There is need to try out the garbage digestion experiments in the semi-arid towns as well as very cold towns in Uganda.