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166 The Journal of the Royal Institute of Thailand Volume III - 2011 166 Cassava Industry in Thailand: Prospects being introduced. It is expected that the national average of cassava root productivity planted with good farm management and selected varieties can be doubled, i.e. from 25 to 50 tons/hectare [5]. In addition, the advances in molecular biology and genetic engineering provides the possibility to develop varieties with improved traits, e.g. high starch yield, specific starch properties, disease and pest resistance, well-adapted to climate change and poor growth conditions. By combining good farming practice with varietal improvement, the root productivity can be potentially improved to more than 50 tons/hectare. Zero-discharge process for cassava production The starch processing technology of Thai cassava industry has been developed from simple extraction and drying processes to modern, fully automated controlling processes. Currently, most cassava starch factories in Thailand are in the transitional stage to become multi-product producers using a zero-discharge process (Figure 4). By implementing the zero-discharge concept (3R - Reduce, Recycle, Replenish), the process of most starch factories now consume less energy (by employing highly efficient equipment), less water (by using recycled water, typically from the separator to root washer), less chemicals (by good handling of raw materials) and less roots (by increasing starch extraction efficiency of machinery). More importantly, the replenishment of biogas obtained from the anaerobic treatment of wastewater instead of petroleum-based energy has remarkably been recognized as another significant development in the progress of the industry. Currently, more than 90% of the total cassava starch factories in Thailand have installed and utilized anaerobic wastewater treatment systems to produce biogas which can cover 100% of the factoryûs thermal energy requirements. Additional biogas is converted to electricity for use in the factory and/or selling back to the grid. The solid waste after starch extraction, i.e. cassava pulp, is also used for biogas production and animal feed in a form of dry tapioca fibre. The development of cassava pulp to other value-added products is also showing continual progress. 160-170_mac9 5/3/12, 11:43 PM 166