DEVELOPMENT OF INTEGRATED ENVIRONMENTAL PROTECTION TECHNOLOGY USING BIO-BRIQUETTES MANUFACTURED FROM LOW-GRADE COAL, BIOMASS WASTE, AND SLAKED LIME, AND ITS COMBUSTION ASH FOR DEVELOPING COUNTRIES

由劣质煤、生物质废弃物和固硫剂组成的煤质生物质成型燃料(BBS)燃烧时排放的二氧化硫(SO2)比劣质煤少，是中国农村酸雨地区生产的一种很好的生活和轻工业燃料。针对酸性土壤碱度高、营养物质含量高的特点，研究了BBS燃烧灰(BB灰)作为酸性土壤改良剂的利用技术。通过生长试验，研究了在酸化土壤中添加BB灰(酸化土壤中含量为5wt%)对萝卜植株生长和植物组织中金属含量的影响。在土壤中添加BB灰，植株的干重和长度都有所增加，说明BB灰既中和了酸化土壤，又含有大量的植物养分钙，从而促进了植物的生长。此外，BB灰的加入抑制了BB灰和酸化土壤中某些植物毒性金属(铝和锰)的淋失，也抑制了植物对金属的吸附。芦苇、香茅、水葫芦等水生植物制成的BBS具有较高的破碎强度，其燃烧灰既可用作土壤中和剂，又可用作土壤肥料，适合作为酸性农业土壤的改良剂。此外，由于重金属衍生燃烧灰对土壤环境的影响较小，估计对土壤环境的不利影响较小。

Coal-biomass briquettes (BBs), which are composed of low-grade coal, biomass waste, and a sulfur fixation agent, emit less sulfur dioxide (SO_2) during combustion than low-grade coal ; thus, BBs are a good manufactured product for use as a domestic and light industrial fuel in rural areas subject to acid rain in China. The aim in this investigation is the development of the utilization technique for combustion ash of BBs (BB ash) as an amelioration agent for acidic soil because it has high alkalinity and contains a lot of nutrients.Growth experiments were conducted to estimate the effects of the addition of BB ash to acidified soil (5wt% in the acidified soil) on the growth of radish plants and on the amounts of metals in plant tissue samples by using a growth chamber. The dry weight and length of plants were increased by the addition of BB ash to the soil, suggesting that plant growth was promoted because BB ash both neutralized acidified soil and contained much calcium, a plant nutrient. In addition, the addition of the BB ash inhibited the leaching of some phytotoxic metals (aluminum and manganese) from the BB ash and acidified soil and also inhibited the adsorption of the metals by plants. The BBs made of water plant such as reed, cattail, and water hyacinth had a high breaking strength and their combustion ash could use as not only soil neutralizing agent but also soil fertilizer.These results suggest that BB ash is suitable as an amelioration agent for acidic agricultural soils. In addition, it was estimated that the adverse effect in soil environment was small because the impact of heavy metal derived combustion ash was small.