Small-scale anaerobic digesters in Vietnam - development and challenges: Review Paper

Small-scale anaerobic digesters, known as biogas plants, were applied as an optimal livestock waste treatment as well as biogas supply for cooking and lighting demand for small-scale farmers in Vietnam. Although the biogas technology was introduced for nearly 30 years, the number of the constructed biogas plants is still limited. The current development of biogas plants is far below the real demand on livestock waste treatment that has increased significantly. This paper gives a comprehensive overview on the biogas plant development in Vietnam and attempts to address the challenges and discuss appropriate solutions for the further biogas development.Mô hình lên men yếm khí quy mô nhỏ (được biết với tên hầm ủ khí sinh học) đã được ứng dụng hiệu quả trong xử lý chất thải chăn nuôi cũng như cung cấp nguồn nhiên liệu phục vụ nhu cầu nấu ăn và thắp sáng cho các hộ chăn nuôi nhỏ ở Việt Nam. Mặc dù đã hiện diện gần 30 năm, nhưng số lượng hầm ủ khí sinh học vẫn còn hạn chế. Sự gia tăng số lượng hầm ủ khí sinh học chưa theo kịp với nhu cầu về xử lý chất thải chăn nuôi đang ngày càng gia tăng. Bài báo trình bày các chặng đường phát triển của hầm ủ khí sinh học tại Việt Nam, ghi nhận các thách thức trong việc nhân rộng hầm ủ khí sinh học trong thực tế và thảo luận một số giải pháp để phát triển công nghệ khí sinh học

Förderung der Anwendung von Biogasanlagen im Mekong-Delta in Vietnam

The study focuses on waste management in the Mekong Delta of Vietnam (MD) through the application of biogas plants to livestock and agricultural waste treatment. The MD accounts for more than 50% of the national aqua-agricultural production in which livestock sector contributes more than 20% of agricultural growth. The livestock sector, however, has been attributed to the environmental problems in the rural MD where the water from the canal network is used as main water supply sources for more than 60% of the local communities. To solve this problem, biogas technology has been applied as an environmentally-friendly treatment for animal and human wastes in the MD since the 1980s. Nevertheless, the number of the existing biogas plants is below the actual local demand on livestock waste treatment due to some impediments such as high investment cost, shortage of input to biogas plants, and limited application of by-products from biogas plants. In an attempt to seek for possible solutions to promote the widespread application of biogas plants in the MD to help improve the sanitary condition of the local communities, our research found water hyacinth and spent mushroom compost, the two local materials, highly potential for using as additional inputs for co-digesters in case of shortage of main biogas plant inputs. In addition, our finding shows that the bio-slurry of the co-digesters could be applied positively to vegetable planting and fish growing, thereby helping farmers generate more income and be engaged in sustainable farming. A new model of biogas plants was also successfully developed and tested in the real local conditions with acceptable investment cost but high treatment efficiency. The findings of our study give more scientific evidence on the benefits of biogas plants to local communities and contribute to the promotion of large-scale application of biogas plants in particularly the rural MD.Die vorliegende Arbeit beschäftigt sich mit der Nutzung von Biogasanlagen zur Verwertung von tierischen und landwirtschaftlichen Abfällen im Mekong-Delta (MD) in Vietnam. Im MD werden mehr als 50% der agrarwirtschaftlichen Erzeugnisse Vietnams produziert, davon sind 20% der Viehwirtschaft zuzuordnen. Die stetig zunehmende Viehhaltung im MD führt jedoch zu großen ökologischen Problemen in den ländlichen Gebieten, insbesondere in Gemeinden, in denen Oberflächenwasser aus dem MD direkt zur Wasserversorgung genutzt wird. Um dieses Problem zu lösen, wurde die Biogas-Technologie bereits in den 1980er Jahren zur umweltfreundlichen Behandlung von Agrarabfällen im MD eingeführt. Dennoch ist die Zahl der errichteten Biogasanlagen im Vergleich zum tatsächlichen Bedarf aufgrund von Investitionskosten, Mangel an geeignetem Substrat und der begrenzten Nutzungs-möglichkeit von Gärresten gering. Deshalb wurde angestrebt, eine geeignete Lösung für die Verbreitung von Biogasanlagen im MD zu finden, die zudem die sanitäre Situation im MD verbessert. Bei dem Bestreben lokal verfügbare Materialien als Substrate für die Biogasanlagen zu verwenden, wurden aufgrund ihrer hohen Biogaspotenziale und ihrer regionalen Verfügbarkeit Wasserhyazinthen (WH) und Pilzkompost (SMC) ausgewählt. Diese Zuschlagstoffe (WH und SMC) haben zudem nach der Co-Vergärung einen positiven Effekt auf den landwirtschaftlichen Anbau und die Aquakultur, sie verhelfen Landwirten zu höheren Einkommen und sensibilisieren sie für eine nachhaltige Landwirtschaft. Die im Rahmen dieser Arbeit entwickelte Biogasanlage konnte unter den Randbedingungen des MD erfolgreich getestet und eine hohe Behandlungseffektivität bei gleichzeitig akzeptablen Kosten festgestellt werden. Der ökonomische und ökologische Nutzen des Einsatzes von Biogasanlagen in den Gemeinden konnte durch die wissenschaftlichen Untersuchungen untermauert werden und eine großflächige Verbreitung in den ländlichen Gebieten des MD wird angestrebt

ENERGY RECOVERY FROM ACTIVE SLUDGE OF WASTEWATER TREATMENT PLANTS

Due to fast growth of industrial sector, the volume of sludge from wastewater treatment systems increases, and this becomes a big problem to the environment. The cost for treatment of sludge is high and requires typical landfill for disposal. This study suggested recovering energy from the sludge of wastewater treatment plants through an anaerobic fermentation process. Sludge from wastewater treatment plants of fish processing factory (C) and shrimp processing factory (T) were collected for the testing of this study. The 20 L lab-scale batch anaerobic digesters were used to ferment sludge which has different humidity of 85 - 90 % and of 95 - 98 %. The biogas yield of the treatment C 85-90 is 305.3, C 95-98 is 444.2, T 85-90 is 144.4, and T 95 - 98 is 171.1 L/kg ODMfermented. After 10 operation days, the percentage of CH4 in the produced biogas was around 50 % which is high enough for energy purposes. The result clearly confirms that sludge from wastewater treatment plants not only is possible treated in anaerobic digesters but also is able to be applied as input material to produce biogas for energy consumption

Enhancing biogas production by anaerobic codigestion of water hyacinth and pig manure

The characteristics of anaerobic batch co-digestion of water hyacinth (WH) with pig manure (PM) under seven mixing ratio 100%WH; 80%WH : 20%PM; 60%WH : 40%PM; 50%WH : 50%PM; 40%WH : 60%PM; 20%WH : 80%PM and 100%PM were investigated, each treatment was conducted in five replications with daily loading rate at 1 gVS.L-1.day-1. During the anaerobic digestion process of 60 days, maximum biogas production occurred in two periods, the first stage from 12- 22 days and second stage from 30 - 35 days. The maximum daily biogas productions from each stage were 17.2 L.day-1 and 15.1 L.day-1, respectively. The cumulative biogas production varied between 60 L (100%PM) and 360 L (60%WH : 40%PM). The results showed that the biogas yields of co-digestion 40- 80%WH were higher from 34.6 to 56.1% in comparison with 100%PM and from 109 to 143% in comparison with 100%WH. When mixing with WH, treatments were received more methane and the methane contents were higher than 45% (v/v) that good for energy using purposes.Nghiên cứu được thực hiện nhằm khảo sát khả năng gia tăng lượng khí sinh học khi tiến hành đồng phân hủy yếm khí lục bình (WH) và phân heo (PM) ở các tỉ lệ phối trộn khác nhau gồm 100%WH; 80%WH : 20%PM; 60%WH : 40%PM; 50%WH : 50%PM; 40%WH : 60%PM; 20%WH : 80%PM và 100%PM. Các nghiệm thức được nạp lượng nguyên liệu là 1 gVS.L-1.ngày-1 và bố trí lặp lại 5 lần. Theo dõi quá trình phân hủy của các nghiệm thức trong 60 ngày ghi nhận có 2 khoảng thời gian lượng khí sản sinh nhiều nhất - giai đoạn 1 từ ngày 12 đến 22, giai đoạn 2 từ ngày 30 đến 35. Lượng khí sản sinh cao nhất tương ứng trong mỗi giai đoạn là 17.2 L.ngày-1 và 15.1 L.ngày-1. Lượng khí tích lũy trong suốt thời gian thí nghiệm ghi nhận thấp nhất ở nghiệm thức 100%PM đạt 60 L, và cao nhất ở nghiệm thức 60%WH : 40%PM đạt 360 L. Năng suất khí sinh ra của các nghiệm thức phối trộn lục bình từ 40 đến 80% cao hơn từ 34,6 đến 56,1% so với nghiệm thức 100%PM và cao hơn từ 109% đến 143% so với nghiệm thức 100%WH. Hàm lượng mê-tan sinh ra từ các nghiệm thức có phối trộn lục bình ổn định trong khoảng > 45% đảm bảo nhiệt lượng cho nhu cầu sử dụng năng lượng

Early Pandemic Influenza (2009 H1N1) in Ho Chi Minh City, Vietnam: A Clinical Virological and Epidemiological Analysis

Rogier van Doorn and colleagues analyze the initial outbreak, attempts at containment, and establishment of community transmission of pandemic H1N1 influenza in Ho Chi Minh City, Vietnam

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Small-scale anaerobic digesters in Vietnam - development and challenges: Review Paper

Small-scale anaerobic digesters, known as biogas plants, were applied as an optimal livestock waste treatment as well as biogas supply for cooking and lighting demand for small-scale farmers in Vietnam. Although the biogas technology was introduced for nearly 30 years, the number of the constructed biogas plants is still limited. The current development of biogas plants is far below the real demand on livestock waste treatment that has increased significantly. This paper gives a comprehensive overview on the biogas plant development in Vietnam and attempts to address the challenges and discuss appropriate solutions for the further biogas development.Mô hình lên men yếm khí quy mô nhỏ (được biết với tên hầm ủ khí sinh học) đã được ứng dụng hiệu quả trong xử lý chất thải chăn nuôi cũng như cung cấp nguồn nhiên liệu phục vụ nhu cầu nấu ăn và thắp sáng cho các hộ chăn nuôi nhỏ ở Việt Nam. Mặc dù đã hiện diện gần 30 năm, nhưng số lượng hầm ủ khí sinh học vẫn còn hạn chế. Sự gia tăng số lượng hầm ủ khí sinh học chưa theo kịp với nhu cầu về xử lý chất thải chăn nuôi đang ngày càng gia tăng. Bài báo trình bày các chặng đường phát triển của hầm ủ khí sinh học tại Việt Nam, ghi nhận các thách thức trong việc nhân rộng hầm ủ khí sinh học trong thực tế và thảo luận một số giải pháp để phát triển công nghệ khí sinh học

Small-scale anaerobic digesters in Vietnam - development and challenges: Review Paper

Small-scale anaerobic digesters, known as biogas plants, were applied as an optimal livestock waste treatment as well as biogas supply for cooking and lighting demand for small-scale farmers in Vietnam. Although the biogas technology was introduced for nearly 30 years, the number of the constructed biogas plants is still limited. The current development of biogas plants is far below the real demand on livestock waste treatment that has increased significantly. This paper gives a comprehensive overview on the biogas plant development in Vietnam and attempts to address the challenges and discuss appropriate solutions for the further biogas development.Mô hình lên men yếm khí quy mô nhỏ (được biết với tên hầm ủ khí sinh học) đã được ứng dụng hiệu quả trong xử lý chất thải chăn nuôi cũng như cung cấp nguồn nhiên liệu phục vụ nhu cầu nấu ăn và thắp sáng cho các hộ chăn nuôi nhỏ ở Việt Nam. Mặc dù đã hiện diện gần 30 năm, nhưng số lượng hầm ủ khí sinh học vẫn còn hạn chế. Sự gia tăng số lượng hầm ủ khí sinh học chưa theo kịp với nhu cầu về xử lý chất thải chăn nuôi đang ngày càng gia tăng. Bài báo trình bày các chặng đường phát triển của hầm ủ khí sinh học tại Việt Nam, ghi nhận các thách thức trong việc nhân rộng hầm ủ khí sinh học trong thực tế và thảo luận một số giải pháp để phát triển công nghệ khí sinh học

Data in brief_NVC Ngan

This dataset is the original data which interpreter for the manuscrip "An experimental study on using water lettuce (Pistia stratiotes L.) to treat anaerobic effluent and feedstock to the anaerobic digester of husbandry" submit to PeerJ.</p