Secondary Logo

Share this article on:

Community Participatory Interventions to Improve Farmer Knowledge and Practices of Household Biogas Unit Operation in Ha Nam Province, Vietnam

Luu, Quoc, Toan, MPH; Nguyen, Mai, Huong, BPH; Nguyen-Viet, Hung, PhD; Pham, Giang, MSc; Dinh-Xuan, Tung, PhD; MacDonald, Lauren, E., MSc; Pham-Duc, Phuc, MD, PhD

Journal of Public Health Management and Practice: March/April 2018 - Volume 24 - Issue - p S28–S35
doi: 10.1097/PHH.0000000000000727
Research Full Reports

Context: The use of biogas systems to treat livestock waste is a common practice in Vietnam. However, farmers' knowledge and practices of the safe and appropriate use of household biogas units (HBUs) are still limited and could negatively impact human, animal, and environmental health.

Objective: To assess the effectiveness of an intervention to improve knowledge and practices of biogas operation among farmers in 2 communes of Ha Nam Province, Vietnam.

Design: A community-based intervention approach.

Setting: This study was conducted from 2015 to 2016 in 2 communes of Ha Nam Province, Vietnam.

Participants: Only farmers with HBUs (N = 399) participated in this research. Farmers were assigned to either an intervention group or a control group at a ratio of 1:2.

InterventionTwo intervention steps were implemented over a 6-month period as follows: (i) the core farmer group trained in 6 steps of HBU safe handling practice; and (ii) the core farmer group conducted peer-to-peer communication with its neighbors in the commune using the provided material.

Main Outcome Measure(s): Farmers' knowledge and practices in biogas operation were assessed by a structured questionnaire. The questionnaire was administered before (baseline) and after the intervention (follow-up) to both the control and intervention groups.

Results: There was a significant difference in the knowledge and practices of biogas operation between the 2 groups, in which farmers in the intervention group demonstrated better understanding of the related topic than the control group (P < .05, t test). A linear regression model indicated that baseline and follow-up scores in both knowledge and practices of the intervention group were higher than those of the control group. After the intervention, the mean difference score in knowledge and practices between the intervention and control groups was 5.0 and 2.0 points, respectively (P < .01).

Conclusion: A community-based intervention approach could be applied to improve knowledge and practices among farmers in using biogas systems. However, further studies should be conducted to assess the sustainability and effectiveness of this model.

Center for Public Health and Ecosystem Research, Hanoi University of Public Health, North Tu Liem District, Hanoi, Vietnam (Mr Luu, Mss Nguyen, Pham, and MacDonald, and Drs Nguyen-Viet and Pham-Duc); National Institute for Animal Science, Thuy Phuong, North Tu Liem District, Hanoi, Vietnam (Dr Dinh-Xuan); and International Livestock Research Institute, Vietnam, Ba Dinh, Hanoi, Vietnam (Dr Nguyen-Viet).

Correspondence: Quoc Toan Luu, MPH, Center for Public Health and Ecosystem Research, Hanoi University of Public Health, No. 1A Duc Thang, North Tu Liem District, Hanoi 10000, Vietnam (lqt@huph.edu.vn).

The authors thank the People Committee and farmers of Hoang Tay commune, Kim Bang District, Ha Nam Province, who supported this study. The authors also thank their FBLI research team and the volunteers for their support. Tran Thi Tuyet Hanh, Julie Hood, and Janna Schurer helped edit English of this article. The International Research Development Center, Canada, funded this research. Hung Nguyen-Viet was partly funded by the CGIAR research program on Agriculture for Nutrition and Health (A4NH). Support for Ms. MacDonald was provided by the Government of Canada through Global Affairs Canada and the Veterinarians Without Borders Volunteer Cooperation Program.

The authors declare no conflicts of interest.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (http://www.JPHMP.com).

Biogas systems are a waste treatment technology that converts organic waste biomass into energy using complex microbial anaerobic digestion. Worldwide, biogas technology has found practical applications at the household level, especially in developing countries. In agricultural countries, millions of biogas units have been installed in recent years.1 Currently, there are 15 types of biogas units used on different agricultural scales that provide economic, health, and environmental benefits.2 Laboratory and empirical assessments show that many factors affect the efficiency of biogas digesters including temperature, waste condition, waste type, pretreatment of waste, and volume of waste used.3

In Vietnam, household biogas units (HBUs) are an appropriate and effective technology to manage animal wastes. Between 2003 and 2012, the Biogas Program for the Animal Husbandry Sector in Vietnam (BP program) supported the construction of 14 000 HBUs, and it is expected that 20 000 additional units will be built by 2018.1 Thousands of biogas units have also been built by commercial companies or freelance builders. The BP program also provided guidance to farmers in the safe and effective operation of HBUs, as the performance depends on the unit design and other factors of the operating process, including the knowledge and practices of the users.4 The BP program's report showed that 92.7% of farmers have been trained to correctly operate their biogas unit.5 However, in Vietnam, an annual survey of biogas users reported that farmers' practices rarely met the recommendations for biogas unit operations. For example, only 2% of farmers measured the daily loading of waste for biogas.5 This could affect human, animal, and environmental health, as overloading of biogas units with waste or water results in improper waste treatment and contaminated biogas effluent entering community waterways.6 , 7

Recently, transdisciplinary approaches have been used to address complex health issues, recognizing the interdependent linkages between societal, economic, cultural, and environmental dimensions and health. This system or ecosystem approach to health, termed “Ecohealth,” addresses these interactions and stresses a heightened focus on people and the sociocultural features that impact their health as well as the health of the environment through the use of participatory processes to affect change.8 As such, community participation has been applied as a principal study method in previous case studies that examined agriculture waste management issues.9–11 The Field Building Learning Initiative (FBLI) was a 5-year development program focused on solving human, animal, and environmental health problems associated with agricultural intensification and other challenges in Southeast Asia.12 FBLI also aimed to develop the practice of Ecohealth to better manage livestock waste and reduce associated health risks. As part of the FBLI in Vietnam, our case study applied a community participatory approach to improve the knowledge and practices of farmers in using biogas units at the household level. This article reports the results of our participatory training intervention, with the objective to improve farmers' handling of HBUs and subsequently improve the health of people and the environment where HBUs are commonly used.

Back to Top | Article Outline

Methods

Study site

The intervention was conducted in Hoang Tay and Chuyen Ngoai communes in Ha Nam Province from 2015 to 2016 (Figure 1). The study site of this intervention was based on results of the sanitation research project that was conducted by the same team, at same study site, and with the same local partner from 2007 to 2011.13 In this area, most households had 1 biogas unit; 90.2% of households used pig manure in their biogas, whereas 29.7% used poultry manure. The volume of the digester was 11.3 ± 3.1 m3 (3.0-22.0 m3). Most of the biogas digesters were built by brick and cement (87%) and plastic (13%).14

FIGURE 1

FIGURE 1

Back to Top | Article Outline

Study setting

The intervention program applied a community participatory approach. It applied the quasi-experimental research design with a control group. The intervention was divided into 3 phases: (i) assess the knowledge and practices of farmers using HBUs before the intervention (baseline); (ii) implement the communication interventions; and (iii) assess the knowledge and practices of farmers using HBUs after the intervention (follow-up).

Back to Top | Article Outline

Sampling strategy

Sample size was calculated on the basis of the hypothesis test for 2 population proportions. The first was the proportion of farmers who exhibited correct biogas use (ie, if a farmer practiced estimation of the daily waste load). This was assumed to be 0.58 based on previous results of the biogas user survey of the BP program. The second proportion was the rate of farmers who had exhibited correct biogas practice after intervention. A coefficient of a multistage clustering sampling method was applied. Farmer participants were divided into either an intervention group or a control group. The sampling process was carried out as follows: in Hoang Tay commune, a cluster of 3 villages was assigned to the intervention group and 6 villages to the control group. In Chuyen Ngoai commune, 1 village was assigned to the intervention group and 6 villages to the control group. Biogas households in each cluster were intentionally selected, and 1 farmer/household was selected. All participants were selected by age (older than 18 years), occupation (farming), and household condition (currently using an HBU on a daily basis).

Back to Top | Article Outline

Intervention tool development and pilot

The study used a “soft” intervention method by using a communication tool package, including a guide to HBU operations, a seasonal calendar, and a set of capacity-building community skills for the farmer (see Supplemental Digital Content Appendix, available at http://links.lww.com/JPHMP/A417 and http://links.lww.com/JPHMP/A418). The intervention framework included 3 phases (Figure 2). First, the farmers were assigned to the core farmer group who were invited to join the intervention group. Two core farmer groups were established for 2 communes, respectively. The sample size of the core farmer group was decided on the basis of the capacity of FBLI. Each core farmer group had 12 farmer participants. In total, 24 farmers were assigned to the 2 core farmer groups as follows: intentionally, the researchers visited the first household of core farmer group candidates for discussion and observation of their HBUs. This activity was carried out with the support of community guides. The candidates were chosen if they were willing to spend their time for intervention activities, change their behavior in the handling of HBUs, and the suitability of the biogas unit in their household. The next candidate was in the nearest neighborhood of the first participant farmer within the intervention group. The research team worked with the core farmer group to develop intervention tools, which included communication materials on knowledge and practices in biogas unit operations, guidelines for cleaning pig stalls and loading biogas waste, and a seasonal calendar with information on biogas operations and maintenance (see Supplemental Digital Content Appendix, available at http://links.lww.com/JPHMP/A417 and http://links.lww.com/JPHMP/A418). These materials were reviewed by a BP program expert. Second, the intervention tools were piloted within the core farmer group over 3 weeks. The core farmer was paired up with another core farmer within the core farmer group at the same commune. Each pair of the core farmer groups applied the pilot guidelines to the operation of both their HBUs. The process was recorded 3 times a week. The tools were adjusted at appropriate points by both the researchers and core group members. At the same time, researchers trained the core group members with skills to become the main communicators of the intervention program. Third, the core group members conducted the peer-to-peer communication. Communication subjects were their neighbors who were in the intervention group. Each core farmer intentionally visited 5 to 7 households so that the core farmer group covered all households in the intervention group. The specific communication contents included knowledge and practice procedure of cleaning of pig stalls and safe handling of HBUs by giving them the guide to HBU operations and the seasonal calendar.

FIGURE 2

FIGURE 2

Back to Top | Article Outline

Questionnaires of knowledge and practices in using biogas and the scoring method

The main points of the questionnaires used to evaluate the knowledge and practices of farmers in using biogas were derived from a published biogas handbook3 , 15 and reviewed by the BP program. There were 20 knowledge questions, divided into 3 main topics: operations, maintenance, and safe use of HBUs. Ten questions related to practice; these were divided into 3 main topics: handling, monitoring, and maintenance of HBUs. Some were multiple-choice questions. Knowledge and practice answers were scored as 1 point for each correct answer, whereas an incorrect answer received no points. The maximum score for knowledge and practices was 38 and 13 points, respectively.

Back to Top | Article Outline

Study variables

The dependent variables of the study were the knowledge and practice score of farmers in safe handling of HBUs. The independent variables of the study were intervention participants, at baseline and follow-up. The control variables of the study were demographic factors, time of using HBUs, and the exposure of information to farmers in using HBUs.

Back to Top | Article Outline

Data analysis

Farmers in both the intervention group and the control group were interviewed using the same questionnaire for baseline and follow-up evaluations. The farmers were chosen for data analysis if they participated in both baseline and follow-up evaluations of the intervention. SPSS 16.0 software was used to analyze the data. Descriptive analysis was carried out to measure the mean score of knowledge and practices of the intervention and control farmer groups for baseline and follow-up evaluations.

Sknewness statistics were used to test the normality of the distribution of knowledge and practice score data before using the t test. The t-test analysis was used to compare the knowledge or practice scores of the intervention and control groups. Paired-samples t test analysis was used to measure the change in knowledge or practice scores within each farmer group (intervention, control) after the intervention (follow-up evaluation). Sknewness statistics were used to test the normality of the distribution of knowledge and practice score data before using the t test.

The t-test analysis was used to compare the knowledge or practice scores of the intervention and control groups. Paired-samples t-test analysis was used to measure the change in knowledge or practice scores within each farmer group (intervention, control) after the intervention (follow-up evaluation). Linear regression analysis was conducted to evaluate the results of communication interventions. In particular, the dependent variable was the difference in knowledge or practice score of the farmers before and after the intervention. The independent variable was the intervention or nonintervention (control). Other variables were used to control confounding factors from the demographic characteristics or biogas user's experience (Table 2). The general linear regression model of this study is described as follows:

Difference mean score = a + b (intervention) + c (control variables)

TABLE 1

TABLE 1

TABLE 2

TABLE 2

Back to Top | Article Outline

Ethical clearance

The study was approved by the Ethical Review Board of Hanoi University of Public Health (no. 041/2013/YTCC-HD3).

Back to Top | Article Outline

Results

In total, 442 farmers were selected as study participants (Table 1) and attended the baseline evaluation. After intervention, 399 farmers attended both baseline and follow-up evaluations and met the paired criteria of the study. Forty-four farmers could not attend the posttest intervention because the researchers could not meet them after 3 visits to their home. The samples lost after intervention were within 15% of the backup sample. The samples lost after intervention did not affect the homogeneity of the participants by demographic factors and some characteristics of HBU utilization (Table 2). The intervention group and the control group comprised 144 and 255 farmers, respectively. Key findings are presented in Table 2.

Demographic factors, time of using HBUs, and the exposure of information to farmers in using HBUs were used to control the consistency of the farmers between the control and intervention groups. The results showed that there was no significant difference between the control and intervention groups in the distribution of age, gender, occupation, educational level, receiving guideline for using HBUs, and duration of using HBUs (P > .05) (Table 2).

The baseline evaluation showed that the average score of farmers' knowledge in using biogas in the intervention group and the control group was 12.1 and 11.8 points, respectively. There was no significant difference in knowledge scores among the intervention and control groups (P > .05). According to follow-up evaluation, the average score of farmers' knowledge in the intervention group and control group was 19.5 and 14.2, respectively. A significant difference in knowledge scores among the intervention and control groups (P < .05) was observed. There was also a significant difference in knowledge score increase among the intervention group and the control group (P < .01) (Table 3).

TABLE 3

TABLE 3

Regarding practice, before the intervention, the average score of farmers in using HBUs in the intervention group and the control group before intervention was 5.6 and 5.4, respectively. There was no significant difference in practice scores among the intervention group and the control group (P > .05). After 6 months of the intervention, there was a change in the score in practices of farmers in using HBUs. The mean score in the intervention group and the control group was 7.9 and 5.8, respectively. There were a significant difference in practice scores among the intervention group and the control group (P < .05) and in the increase of practice score among the intervention group and the control group (P < .01) (Table 3).

The linear regression model results showed that the difference in knowledge score after and before the intervention in the intervention group was 5.0 points higher than that of the control group (P < .01) (Table 4). The linear regression analysis was applied to analyze the difference in practice scores after and before the intervention in the intervention group, which was 2.0 points higher than that of the control group (P < .01) (Table 4).

TABLE 4

TABLE 4

Back to Top | Article Outline

Discussion

Our study used a participatory approach to introduce an intervention to improve farmers' knowledge and practices in using HBUs in a rural area in Vietnam. It shows that the intervention group had better knowledge and practices in using biogas operation after the intervention than the control group and that pretest and posttest scores in knowledge or practices of the intervention group were higher than those of the control group.

Over the past 2 decades, Vietnam's animal husbandry has been rapidly developing that has led to the rise in the quantity of animal waste and waste by-products. In this context, an HBU is often used as an effective measure for treating wastes.6 , 7 However, the impact of biogas use on the economy, environment, and health is not yet well understood. Our research showed that the biogas wastewater is still highly contaminated with several pathogens, for example, Escherichia coli (14.7 × 105 colony-forming units/100 mL), Giardia (19 cysts/100 mL), and Cryptosporidium (18 oocysts/100 mL).14 As a consequence, the environment has been polluted and human health has been affected by HBU effluent.14 , 16–18 The results of our intervention provided initial evidence on enhancing farmers' knowledge and practices in HBU operation by introducing simple intervention in a rural setting. The knowledge and practices in HBU operation of farmers were improved, which enhances the efficiency of HBUs and therefore would lead to reduced health risk from exposure to polluted HBU effluents in agriculture activities.

Participatory approach was the key factor of our intervention program. Ecohealth is an approach in which various research methods derived from different disciplines are used, including qualitative and quantitative methods, such as literature reviews, cross-sectional surveys, participatory rural appraisal, laboratory testing, action research, and on-farm intervention.8

This approach was geared toward planning and conducting the research process with interdisciplinary researchers, local authorities, and farmers, who worked together throughout the project cycle (identification of problems, designing of intervention based on identified problems, implementation of intervention, and evaluation of outcome). The research teams worked with local communities and stakeholders to explore and pilot innovative solutions to address the identified health and ecosystem issues. Interventions using communication tools usually achieve consensus among participants.8 In the current study, the farmers easily accepted instructions of the intervention program because these tools were developed on the basis of their daily activities. In practice, the 6-step cleaning guideline for pig housing was important for the intervention. The guideline focused on the operation, maintenance, and monitoring of HBUs. With the core group farmers' activities, communication intervention had earlier changed farmers' knowledge in operating HBUs and using biogas. Results of the study show that the intervention immediately improved the knowledge and practices of the farmers in using HBUs. After the intervention, the knowledge and practice scores of the intervention group were significantly higher than those of the control group (P < .01) whereas this was not present before the intervention.

This intervention program used the “soft” tools on knowledge and practices of the farmers in using HBUs. The HBU infrastructure did not change or was not repaired. Also, households should not spend any of their finance for intervention activities. The improved knowledge and practices of the farmers in using HBUs showed the success of this intervention program. After intervention, the mean scores of farmers' knowledge and practices in operating HBUs were enhanced by 7.4 and 2.3 points, respectively. According to the literature, we did not find any report of interventions on knowledge and practice improvement of farmers in using HBUs. Most of them focused on the application such as new technology,1 , 19 , 20 biogas benefits,5 , 21–23 and evaluation criteria of biogas. In some reports related to biogas development programs of other countries, some studies provided the status of a certain aspect of using biogas.5 , 7 , 22 While other studies show that HBUs in Vietnam discharge low-quality wastewater with high contamination of pathogens,6 , 7 it is important to pay more attention to the health risk related to biogas wastewater and exposure to biogas wastewater when handling them in agricultural activities such as irrigation. Preventive measures need to be put in place such as wearing personal protection equipment when cleaning livestock housing and safe reuse of biogas wastewater in agriculture. There is a growing awareness of the need to improve sanitation in livestock farming practice, driven by a need to reduce pollution caused by pig waste management in these 2 communes. Agricultural Innovation Systems Approach looks at the multiple conditions and relationships that promote innovation in agriculture: Research, education, and extension are usually necessary but not sufficient to bring knowledge, technologies, and services to farmers and entrepreneurs to innovate.24 Innovation requires a much more interactive, dynamic, and ultimately flexible process in which the actors deal simultaneously with many conditions and complementary activities that go beyond the traditional domains of R&D and extension. Farmer-led innovation in agriculture is the process through which individuals or groups within a given locality discover or develop and apply improved ways of managing the available resources by building on and expanding the boundaries of their indigenous knowledge. According to the World Bank (2004), local (farmer) innovation refers to the dynamics of indigenous knowledge, that is, knowledge that grows within a social group, incorporating not only learning from their own experience over generations but also external knowledge internalized within the local ways of thinking and doing.25 These points were covered in our intervention, showing that improvement in knowledge and practices of farmers, therefore, should be replicated in other areas of similar context in using HBUs. The intervention program had built the core group that was an important basis to keep the communication activities going on after the intervention time.

Back to Top | Article Outline

Limitation of the study

The results of the study also indicated some limitations during the study design and implementation phases. First, the selection of the intervention group and the control group within the commune did not create a sufficiently large gap to ensure control information from the intervention. This condition might lead to some spillovers of information from intervention communes to control communes. Second, the evaluations were made immediately after the intervention finished. That did not reflect the sustainable impact of the intervention program. Third, the change in knowledge and practices may not be strong enough to immediately confirm the change in effectiveness of the HBU performance. Further research should focus on the assessment of changes that are based on the change of economic and health benefits. In addition, long-term evaluation should be designed to estimate the sustainability of the intervention.

Back to Top | Article Outline
Implication for Policy & Practice
  • Intervention results provide initial evidence on the effectiveness of the community participatory approach that was applied to address the issues in agricultural waste management using HBUs. The innovation is based on knowledge and practice changes that enhance the effectiveness of HBU operation.
  • The “soft” intervention on knowledge and practice improvement did not require infrastructure change of HBUs. This would get more easily the commitment and acceptance of the community.
  • The intervention program was a case study that applied the Ecohealth approach that involved the participation of the community and other stakeholders (transdisciplinarity) to consider their animal waste management in a socioecological context.
  • As far as we can see, other applications of the community participatory approach are to resolve agriculture issues such as inappropriate disposal and handling of pesticides in crop and vegetable production in this community. Pesticides are widely used in crop production, especially in cucumber farming in this community; this practice leads to pollution of the environment, including soil and water.
Back to Top | Article Outline

Conclusion

A community-based intervention approach was effective in enhancing the farmers' knowledge and practices in using HBUs. Communication activities should be continued in the core group to maintain sustainability of the intervention. It is possible to develop a core group model that applies to other issues in agriculture waste management.

Back to Top | Article Outline

References

1. Cheng S, Li Z, Mang HP, Huba EM, Gao R, Wang X. Development and application of prefabricated biogas digesters in developing countries. Renewable Sustainable Energy Rev. 2014;34:387–400.
2. Rao B, Mane A, Rao AB, Sardeshpande V. Multi-criteria analysis of alternative biogas technologies. Energy Procedia. 2014;54:292–301.
3. Murphy JD, Thanasit T. Fundamental science and engineering of the anaerobic digestion process for biogas production. In: The Biogas Handbook. Cambridge, UK: Woodhead Publishing; 2013:104–130.
4. Drosg B, Braun R, Bochmann G, Al Saedi T. Analysis and characterisation of biogas feedstocks. In: Murphy J, Baxter D, eds. The Biogas Handbook. Cambridge, UK: Woodhead Publishing; 2013:52–84.
5. Dung NQ. Biogas User Survey in Vietnam 2010-2011. Hanoi, Vietnam: The Biogas Program for the Animal Husbandry Sector in Vietnam; 2011.
6. Huong LQ, Madsen H, Anh LX, Ngoc PT, Dalsgaard A. Hygienic aspects of livestock manure management and biogas systems operated by small-scale pig farmers in Vietnam. Sci Total Environ. 2014;470:53–57.
7. Thien Thu CT, Cuong PH, Hang LT, et al Manure management practices on biogas and non-biogas pig farms in developing countries—using livestock farms in Vietnam as an example. J Cleaner Prod. 2012;27:64–71.
8. Charron DF. Ecohealth Research in Practice. New York, NY: Springer; 2012.
9. Dhokhikah Y, Trihadiningrum Y, Sunaryo S. Community participation in household solid waste reduction in Surabaya, Indonesia. Resour Conserv Recycl. 2015;102:153–162.
10. Sinclair AJ, Sims L, Spaling H. Community-based approaches to strategic environmental assessment: lessons from Costa Rica. Environ Impact Assess Rev. 2009;29(3):147–156.
11. Malhotra P, Neudoerffer RC, Dutta S. A participatory process for designing cooking energy programmes with women. Biomass Bioenergy. 2004;26(2):147–169.
12. Field Building Leadership Initiative. Advancing Ecohealth in Southeast Asia and China: lessons from the Field Building Leadership Initiative. http://http://www.ecohealthasia.net/images/FBLI_Final_Report_2016_for_Open_Access-_December_2016.pdf. Published 2016. Accessed September 19, 2017.
13. Nguyen V, Nguyen-Viet H, Pham-Duc P, Stephan C, McEwen SA. Identifying the impediments and enablers of Ecohealth for a case study on health and environmental sanitation in Ha Nam, Vietnam. Infect Dis Poverty. 2014;3(1):36.
14. Le-Thi T, Pham-Duc P, Zurbrügg C, et al Diarrhea risks by exposure to livestock waste in Vietnam using quantitative microbial risk assessment. Int J Public Health. 2017;62(suppl 1):83–91.
15. Da Costa Gomez C. Biogas as an energy option: an overview. In: Murphy J, Baxter D, eds. The Biogas Handbook. Cambridge UK: Swiss: Woodhead Publishing; 2013:1–16.
16. Huong LQ, Forslund A, Madsen H, Dalsgaard A. Survival of Salmonella spp. and fecal indicator bacteria in Vietnamese biogas digesters receiving pig slurry. Int J Hyg Environ Health. 2014;217(7):785–795.
17. Yen-Phi VT, Clemens J, Rechenburg A, Vinneras B, Lenssen C, Kistemann T. Hygienic effects and gas production of plastic bio-digesters under tropical conditions. J Water Health. 2009;7(4):590–596.
18. Pham-Duc P, Nguyen-Viet H, Hattendorf J, et al Diarrhoeal diseases among adult population in an agricultural community Hanam Province, Vietnam, with high wastewater and excreta re-use. BMC Public Health. 2014;14:978.
19. Lora Grando R, de Souza Antune AM, da Fonseca FV, Sánchez A, Barrena R, Font X. Technology overview of biogas production in anaerobic digestion plants: a European evaluation of research and development. Renewable Sustainable Energy Rev. 2017;80:44–53.
20. Deng L, Liu Y, Zheng D, et al Application and development of biogas technology for the treatment of waste in China. Renewable Sustainable Energy Rev. 2017;70:845–851.
21. Sun MT, Fan XL, Zhao XX, et al Effects of organic loading rate on biogas production from macroalgae: performance and microbial community structure. Bioresour Technol. 2017;235:292–300.
22. Chen Y, Hu W, Chen P, Ruan R. Household biogas CDM project development in rural China. Renewable Sustainable Energy Rev. 2017;67:184–191.
23. Yasar A, Nazir S, Rasheed R, Tabinda AB, Nazar M. Economic review of different designs of biogas plants at household level in Pakistan. Renewable Sustainable Energy Rev. 2017;74:221–229.
24. The World Bank. Agricultural innovation systems. http://siteresources.worldbank.org/INTARD/Resources/335807-1330620492317/9780821386842.pdf. Published 2012. Accessed September 19, 2017
25. The World Bank. Promoting local innovation: enhancing IK dynamics and links with scientific knowledge. https://openknowledge.worldbank.org/bitstream/handle/10986/10761/312650iknt76.pdf?sequence=1&isAllowed=y. Published 2005. Accessed September 19, 2017.
Keywords:

biogas; community-based; intervention; health risk; Vietnam

Supplemental Digital Content

Back to Top | Article Outline
Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.