Energy efficiency in an integrated agro-ecosystem within an acidic soil area of the Mekong Delta, Vietnam

Abstract

Background Both exergy and energy analysis methodologies are used for analysing energy efficiencies in various processes, including agriculture. This study focuses on the connection of three main process components (husbandry-crop-fishpond) in a typical farming household located within an acid soil region of rural Vietnam. The concept of exergy analysis is used to underline the potential for resource efficiency in alternative processes in the agricultural system. For development of an integrated ecological system aiming towards zero emissions, the analytical methods of material cycles and energy flows utilized a set of indicators of resource efficiency in a sustainable agriculture. Results The design of the ideal integrated farming system “Agro-Industrial Zero Emissions Systems” (AIZES) can increase the system efficiency by making use of indigenous natural materials and waste reuse/recycling. Recycling waste produce energy, fish feed and fertilizer can result in a decreased environmental load of approximately half. Using exergy analysis to calculate an indicator non-renewable yield ratio (NRYR), the systems verified sustainability of agriculture production. Conclusions The farming household will be able to subsidize their fuel and electricity consumption by utilizing biogas. Surplus biogas will be distributed to proximate households, further creating sustainable goals. Biochar, created by mixing the biomass residues with local plants, will improve soil quality and pig sludge, mixed with biomass residue, will create high-quality fertilizer.

Hatching success and growth of Snakehead (Channa lucius Cuvier, 1831) larvae and fry at different pH levels

“…Besides useful freshwater resources, the Mekong Delta still has a rather large area (approximately 1.6 million ha) of highly acid sulfate soils (Sumida et al, 2012) that cover more than 40% of the region's agricultural land, acidifying the receiving waters (Guong and Hoa, 2012;Trinh, 2017;Thao et al, 2020). Even in several small rivers and canals in some of the Mekong Delta provinces, the pH levels of the surface water are commonly only 4.5-5.5 (Trinh, 2017), leading to limitations in aquaculture and agriculture production in the area.…”

Specific energy consumption and heat recovery system of cassava starch production in the integrated agro-industrial system

“…Integrated systems based on waste-to-energy conversion can increase system efficiency by making use of indigenous natural materials and waste reuse/recycling. Recycling of waste can produces energy, fish feed, and fertilizer, and it results in a decreased environmental impact of approximately 50% (Le et al, 2016;Thao et al, 2020).…”