Regional Diagnosis of Biomass Use in Suburban Village in Southern Vietnam

Abstract

To establish a sustainable regional biomass use system, clarifying the present condition in the objective area and proposing a proper scenario to improve the present conditions are important. In this study, one suburban village where rice cultivation and livestock industries are popular in Southern Vietnam was selected as the objective area.Literature review, interviews at the site and field surveys were conducted to analyze material flow in agricultural production and excreta treatment of livestock. As a result, it was clarified that surface water quality at some points in the canals, rivers and wells of the village did not meet the national standard, and contributions of discharges of untreated livestock excreta to total nitrogen loads to lower water bodies were large (43% in total). From another aspect, some rice straw was burned without any effective use at the paddy fields. For this situation, two scenarios were proposed and designed as "Plan model 1" and "Plan model 2". The one is to increase biogas digesters in the village for treatment of untreated livestock excreta, decrease washing water rate poured into biogas digesters and use slurry from the biogas digester (hereafter, slurry) at paddy and non-paddy fields as a fertilizer. Another is to use unused rice straw for producing bio-ethanol. By these scenarios, the possibility was shown that approximately 327,000 Nm 3 /year of biogas and more than 240 kL/year ( ≓ 190 t/y) of bio-ethanol can be produced in objective village, 39% of nitrogen load to water bodies and 95% of application rate of chemical fertilizer to agricultural field could be decreased, and greenhouse gas emission rate could be decreased if bio-ethanol is substituted for fossil fuel.

Satellites may underestimate rice residue and associated burning emissions in Vietnam

“…We compared the resulting rice burning emissions estimates with an existing emissions inventory (regional emission inventory in Asia (REAS)) for the latest available year, 2008 (Kurokawa et al 2013). We calculated Vietnam’s total emissions (equation (3)) for different scenarios including the maximum potential emissions (all residue burned), and the most-likely scenarios of straw and stubble burning based on the literature and our field experience suggesting approximately 50% of straw burned and 10% of stubble burned (Nguyen 2012, Hong Van et al 2014, Tran et al 2014, Duong and Yoshiro 2015, Oritate et al 2015).…”

“…Typical burning of a rice straw pile and post-burned field in Hanoi are shown (figures 2( a ) and ( b )). Mostly, the straw is burned or reincorporated into the soil while some is used for cattle feed, cook stoves, composting, and mushroom cultivation (Trach 1998, Hong Van et al 2014, Duong and Yoshiro 2015, Nguyen 2012, Oritate et al 2015). In comparison to the rural areas, suburban areas such as Hanoi typically burn a higher proportion of rice straw as these areas have fewer cattle relying on it for food (Duong and Yoshiro 2015).…”

Improved rice residue burning emissions estimates: Accounting for practice-specific emission factors in air pollution assessments of Vietnam

“…Whereas, the former FL is representative of the common double-cropped rice fields found in the rest of Vietnam. PB is assumed as 50% for straw and 10% for stubble gathered from previous field studies in Vietnam (Trach, 1998;Hong Van et al, 2014;Duong and Yoshiro, 2015;Oritate et al, 2015).…”