Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam

This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank.

[1]  Huang Ning-sheng,et al.  Popularizing household-scale biogas digesters for rural sustainable energy development and greenhouse gas mitigation , 2008 .

[2]  S. O. Petersen,et al.  Methane and carbon dioxide emissions and nitrogen turnover during liquid manure storage , 2007, Nutrient Cycling in Agroecosystems.

[3]  Navindu Gupta,et al.  Methane emission from fixed dome biogas plants in hilly and plain regions of northern India. , 2004, Bioresource technology.

[4]  Pham Hung Cuong,et al.  Manure management practices on biogas and non-biogas pig farms in developing countries - using livestock farms in Vietnam as an example. , 2012 .

[5]  I. Angelidaki,et al.  Kinetics and modeling of anaerobic digestion process. , 2003, Advances in biochemical engineering/biotechnology.

[6]  Ori Lahav,et al.  Rapid, simple, and accurate method for measurement of VFA and carbonate alkalinity in anaerobic reactors. , 2002, Environmental science & technology.

[7]  Jin Mi Triolo,et al.  Predicting methane production in simple and unheated biogas digesters at low temperatures. , 2014 .

[8]  Sunil Herat,et al.  Biogas as a sustainable energy source in Nepal: Present status and future challenges , 2009 .

[9]  Thomas Kätterer,et al.  Predicting daily soil temperature profiles in arable soils in cold temperate regions from air temperature and leaf area index , 2009 .

[10]  Knud Villy Christensen,et al.  A review of the biogas industry in China , 2011 .

[11]  J. Herrero,et al.  Transfer of low-cost plastic biodigester technology at household level in Bolivia. , 2007 .

[12]  J. Monod.  The Growth of Bacterial Cultures , 1949 .

[13]  Anjan K. Kalia,et al.  Horse dung as a partial substitute for cattle dung for operating family-size biogas plants in a hilly region , 1998 .

[14]  S. C. Bhattacharya,et al.  Renewable energy in India: Historical developments and prospects , 2009 .

[15]  Laia Ferrer-Martí,et al.  Codigestion of cow and guinea pig manure in low-cost tubular digesters at high altitude. , 2011 .

[16]  Thibault Perrigault,et al.  Towards thermal design optimization of tubular digesters in cold climates: a heat transfer model. , 2012, Bioresource technology.

[17]  Binxin Wu,et al.  DEVELOPMENT OF 3-D ANAEROBIC DIGESTER HEAT TRANSFER MODEL FOR COLD WEATHER APPLICATIONS , 2006 .

[18]  L. S. Jensen,et al.  Small-scale household biogas digesters: An option for global warming mitigation or a potential climate bomb? , 2014 .

[19]  P. Grau,et al.  Kinetics of multicomponent substrate removal by activated sludge , 1975 .

[20]  Jingwei Ma,et al.  Kinetics of psychrophilic anaerobic sequencing batch reactor treating flushed dairy manure. , 2013, Bioresource technology.

[21]  B. Ahring,et al.  Methane productivity of manure, straw and solid fractions of manure , 2004 .

[22]  Andrew G. Hashimoto,et al.  Kinetics of methane fermentation , 1978 .

[23]  S. Kanwar,et al.  Long-term evaluation of a fixed dome Janata biogas plant in hilly conditions , 1998 .

[24]  Methane Emission Patterns from Stored Liquid Swine Manure , 2010 .

[25]  Sonal Anand,et al.  New Delhi, India , 2011 .

[26]  D. T. Hill.  Methane Productivity of the Major Animal Waste Types , 1984 .

[27]  Bin Chen,et al.  Rural energy in China: pattern and policy. , 2009 .

[28]  Trine Lund Hansen,et al.  Methane production during storage of anaerobically digested municipal organic waste. , 2006, Journal of environmental quality.

[29]  Charles W. Boast,et al.  Introduction to Soil Physics , 1983 .

[30]  K. Treanton,et al.  Revised 1996 IPCC guidelines for national greenhouse gas inventories. v. 1: Greenhouse gas inventory reporting instructions.- v. 2: Greenhouse gas inventory workbook.- v.3: Greenhouse gas inventory reference manual , 1997 .

[31]  N. K. Bansal,et al.  Effect of PVC greenhouse in increasing the biogas production in temperate cold climatic conditions , 1987 .