The proliferation of food, feed and biofuels demands promises to increase pressure on water competition and stress, particularly for Thailand, which has a large agricultural base. This study assesses the water footprint of ten staple crops grown in different regions across the country and evaluates the impact of crop water use in different regions/watersheds by the water stress index and the indication of water deprivation potential. The ten crops include major rice, second rice, maize, soybean, mungbean, peanut, cassava, sugarcane, pineapple and oil palm. The water stress index of the 25 major watersheds in Thailand has been evaluated. The results show that there are high variations of crop water requirements grown in different regions due to many factors. However, based on the current cropping systems, the Northeastern region has the highest water requirement for both green water (or rain water) and blue water (or irrigation water). Rice (paddy) farming requires the highest amount of irrigation water, i.e., around 10,489 million m3/year followed by the maize, sugarcane, oil palm and cassava. Major rice cultivation induces the highest water deprivation, i.e., 1862 million m3H₂Oeq/year; followed by sugarcane, second rice and cassava. The watersheds that have high risk on water competition due to increase in production of the ten crops considered are the Mun, Chi and Chao Phraya watersheds. The main contribution is from the second rice cultivation. Recommendations have been proposed for sustainable crops production in the future.

Bioenergy from cassava is a promising alternative energy source for both energy supply and the mitigation of greenhouse gases. However, major global trends, such as climate change and competing landuse patterns, pose substantial risks to the sustainable development of bioenergy. The main purpose of this study was to assess the sustainable development of bioenergy from cassava, considering landuse change and climate change with a biogeochemical process model within the “water-energy-food” nexus framework. The results showed that the land resources that were suitable for the development of cassava bioenergy have continuously decreased in China since 1990. At the same time, the climate has also undergone significant changes, with temperature showing an increasing trend, and precipitation showing a decreasing trend. With the influences of both landuse change and climate change, the total bioenergy of cassava showed a downward trend. In China, the potential bioenergy production for the year 1990, 2000, and 2010 was 6075 PJ, 5974 PJ, and 4399 PJ, respectively. Compared to 1990, the bioenergy production in 2010 decreased by 1676.40 million GJ, which equals 57 million tons of standard coal. In addition, the water footprint of bioenergy from cassava was discussed. After considering changes to landuse, climate, and water footprint, it was concluded that Guangxi was the most suitable place to develop cassava bioenergy, followed by Fujian, Guangdong, and Yunnan.

Yam peel (YP), cassava peel (CP), cocoyam peel (CoP) and plantain peel (PP) are common food wastes of the Niger Delta region. Anaerobic digestion (AD) of these wastes with water hyacinth (WH) presents a viable way of both providing renewable energy and cleaning up the environment. AD tests were carried out on the food wastes and WH to determine their biogas potentials. The experiments were carried out under mesophilic conditions at (37 ± 1 °C) over a period of 20 days and the tests were replicated to give an indication of repeatability. The results showed that YP+WH, CP+WH, CoP+WH and PP+WH had specific biogas yields of 0.42, 0.29, 0.39 and 0.38 m³/kg volatile solid (VS), respectively. The yields represented 76, 48, 70 and 69% of their respective theoretical values. Co-digesting the food wastes with WH in a VS ratio of 2:1 reduced the biogas yields of YP, CP, CoP and PP by 16, 22, 7 and 7%, respectively. The drop in gas production was due to indigestible complex molecules in the WH co-substrate. The results indicate that common food wastes in the Niger Delta can be used as feedstock for AD, but co-digesting with WH reduces the biogas yield.

Biogas, generated from anaerobic digester (AD), has been one of the promising sources of renewable energy. To manage the organic waste from small cassava industry in Brazil, a waste-water-energy-food nexus (WWEF) system is proposed, combining AD and co-generation or combined heat and power (CHP) plants. However, the environmental impacts and benefits of this system are yet not known. By using Life Cycle Assessment (LCA) method, environmental impacts of three scenarios are assessed, i.e. business-as-usual (base), improved business-as-usual and WWEF closed-loop. Functional unit (FU) in this study is defined as generating 1 kg cassava starch/flour. Global warming potential (GWP), cumulative energy demand (CED), freshwater eutrophication potential (FEP), terrestrial acidification potential (TAP) and water depletion potential (WDP) are selected. Landfilling cassava waste, power use for cassava starch and flour production, and emissions from fertilizer application are identified as environmental hotspots for business-as-usual case, suggesting making decisions on these aspects when dealing with environmental impacts. By using cassava waste to recover energy and nutrients for Brazilian rural family farming, the WWEF system is identified as the best environment-friendly scenario with lowest environmental impacts for the selected impact categories. The impact savings of the closed-loop scenario for GWP are over 90%, while over 50% of emissions for other selected impact categories, except FEP (lower than 10%), are saved compared to the business-as-usual and improved scenarios. Sensitivity analysis reinforces the results. Overall, this study provides a view on the potential of using cassava waste for the WWEF closed-loop system in Brazil, suggesting that the proposed WWEF closed-loop system is feasible and beneficial for small industries from the environmental perspective.

Report submitted to Food and Agriculture Organization (FAO) under the project, "Comparative assessment of water usage and impacts arising from biofuel projects in SOUTHEAST ASIAn Countries?, commissioned by the Letter of Agreement No LOA/RAP/2009/38. Thailand and Malaysia are two SOUTHEAST ASIAn countries with rapidly growing biofuel demand. Increasing use of biofuel envisages reducing dependence of petroleum products for transport and mitigating environmental impacts by reducing carbon emissions. It also expects to contribute to rural development and poverty reduction. However, the impacts of expanding production of feedstock for biofuel on water supply are not well understood. This paper assesses the water footprints and impacts of sugarcane molasses and cassava based bioethanol in Thailand, and palm oil based biodiesel in Malaysia. The water footprint of a commodity or service is the water depleted in its life cycle of its production or consumption. The total water footprints of sugarcane molasses and cassava bioethanol production in Thailand are estimated to be 1,646 and 2,304 m3/tonne, respectively, and of palm oil biodiesel in Malaysia is 3,730 m3/tonne. However, the contributions from irrigation are only a small fraction --9.0, 0.7 and 0.3%-- of the total water footprints of molasses and cassava bioethanol, and palm oil biodiesel respectively. In terms of irrigation water use,cassava is a better feedstock for bioethanol production than sugarcane molasses. In Thailand, the total annual irrigation water footprints in bioethanol production --54 million m3 (mcm) for molasses and 15 mcm for cassava-- is only 0.02% of the total renewable water resources. In Malaysia, total annual irrigation water footprint of palm oil biodiesel production is only 0.001% of the total renewable water resources. A significant spatial variation of irrigation water footprints of molasses based ethanol exists across provinces in Thailand, indicating potential for reducing water footprints. The total irrigation water footprints in biofuel production in the future in both countries will also be negligible in comparison to total water availability. However, the impact of wastewater generated in the production processes can have significant impacts on quality of local water resources. A part of the waste water, called 'spent wash', is applied as fertilizer, and over use of it can affect soil and neighboring water resources. The proposed plans on biofuel production in the future can generate more 'spent wash' than that can be used in crop fields as fertilizer. Spent wash has found to have high PH value, temperature, biological and chemical oxygen contents etc. The usual practice of storing spent wash in a pond for a long period near a plant can have detrimental impact on soil, streams' and groundwater quality. In sum, this study concludes that from the perspective of quantity of irrigation water use, the increasing biofuel production does not pose a major problem in Thailand or in Malaysia, and cassava is a better feedstock than sugarcane molasses for bioethanol production. However, the quality of water resources with increasing effluents generated by the biofuel plants could be a major environmental bottleneck to guard against | Upali A. Amarasinghe, Nishadi Eriyagama, Wannipa Soda, 'Growing biofuel demand in Thailand and Malaysia: water use and impacts. Project report submitted to Food and Agriculture Organization (FAO) under the project, "Comparative assessment of water usage and impacts arising from biofuel projects in SOUTHEAST ASIAn Countries?', International Water Management Institute (IWMI), 2014

Report submitted to Food and Agriculture Organization (FAO) under the project, "Comparative assessment of water usage and impacts arising from biofuel projects in SOUTHEAST ASIAn Countries?, commissioned by the Letter of Agreement No LOA/RAP/2009/38. Thailand and Malaysia are two SOUTHEAST ASIAn countries with rapidly growing biofuel demand. Increasing use of biofuel envisages reducing dependence of petroleum products for transport and mitigating environmental impacts by reducing carbon emissions. It also expects to contribute to rural development and poverty reduction. However, the impacts of expanding production of feedstock for biofuel on water supply are not well understood. This paper assesses the water footprints and impacts of sugarcane molasses and cassava based bioethanol in Thailand, and palm oil based biodiesel in Malaysia. The water footprint of a commodity or service is the water depleted in its life cycle of its production or consumption. The total water footprints of sugarcane molasses and cassava bioethanol production in Thailand are estimated to be 1,646 and 2,304 m3/tonne, respectively, and of palm oil biodiesel in Malaysia is 3,730 m3/tonne. However, the contributions from irrigation are only a small fraction --9.0, 0.7 and 0.3%-- of the total water footprints of molasses and cassava bioethanol, and palm oil biodiesel respectively. In terms of irrigation water use,cassava is a better feedstock for bioethanol production than sugarcane molasses. In Thailand, the total annual irrigation water footprints in bioethanol production --54 million m3 (mcm) for molasses and 15 mcm for cassava-- is only 0.02% of the total renewable water resources. In Malaysia, total annual irrigation water footprint of palm oil biodiesel production is only 0.001% of the total renewable water resources. A significant spatial variation of irrigation water footprints of molasses based ethanol exists across provinces in Thailand, indicating potential for reducing water footprints. The total irrigation water footprints in biofuel production in the future in both countries will also be negligible in comparison to total water availability. However, the impact of wastewater generated in the production processes can have significant impacts on quality of local water resources. A part of the waste water, called 'spent wash', is applied as fertilizer, and over use of it can affect soil and neighboring water resources. The proposed plans on biofuel production in the future can generate more 'spent wash' than that can be used in crop fields as fertilizer. Spent wash has found to have high PH value, temperature, biological and chemical oxygen contents etc. The usual practice of storing spent wash in a pond for a long period near a plant can have detrimental impact on soil, streams' and groundwater quality. In sum, this study concludes that from the perspective of quantity of irrigation water use, the increasing biofuel production does not pose a major problem in Thailand or in Malaysia, and cassava is a better feedstock than sugarcane molasses for bioethanol production. However, the quality of water resources with increasing effluents generated by the biofuel plants could be a major environmental bottleneck to guard against.