水耕植物过滤法去除氮磷的影响因素及途径

采用水耕植物过滤法(hydroponic bio-filter method,HBFM)净化富营养化地表水的试验表明,在水力负荷为3.0 m³/(m²·d)的条件下,TN、TP年平均去除率分别为16.8%、30.8%,年平均去除速率分别为1.0、0.1 g/(m²·d)．通过底泥沉积去除的氮、磷分别占系统氮、磷总去除量的62.2%和75.9%,是TN、TP最主要的去除途径．HBFM的最佳水力负荷为3.0～4.0 m³/(m²·d).西洋菜收割时的剪割强度影响其氮磷吸收速率,每次剪割长度不得超过10　cm.收割频率为1次/月时不会影响HBFM的氮磷去除效果.     

Composition of green turtle feeding aggregations along the Japanese archipelago: implications for changes in composition with current flow

In order to develop effective conservation strategies for endangered migratory species, the link between feeding and breeding grounds needs to be clarified. In this study, the genetic compositions of consecutive Japanese feeding aggregations of green turtles (Chelonia mydas) along the Kuroshio Current were examined by mixed-stock analyses of mitochondrial DNA control-region sequences. The results indicated that the southern feeding aggregation around Yaeyama (24.3°N, 124.0°E) was sourced from various Pacific rookeries in the Yaeyama, Ogasawara, Western Pacific, and Indian Oceans and Southeast Asia. Among northern feeding aggregations, the Ginoza (26.5°N, 128.0°E) aggregation was also sourced from the Western Pacific Ocean, but the Nomaike (31.4°N, 130.1°E), Muroto (33.2°N, 134.2°E), and Kanto (35.6°N, 140.5°E) aggregations were contributed mostly by the closer Ogasawara rookeries. The reduced contribution from tropical Pacific rookeries to northern feeding aggregations and the significant correlation between genetic differentiation and geographical distance matrices of feeding aggregations indicated that most hatchlings from these regions transported by the Kuroshio Current settle in upstream feeding grounds along the Japanese archipelago, implying that current flow influences the composition of feeding aggregations. Differences in the composition of relatively close neritic feeding aggregations have important conservation implications, for which both regional and multinational conservation strategies are needed.     

水耕植物过滤法净水系统底泥硝化反硝化潜力

通过测定水耕植物过滤法(Hydroponic Bio-filter Method,HBFM)水质净化系统中底泥的硝化、反硝化潜力以及底泥中亚硝酸菌和硝酸菌密度,定量研究了该系统底泥的硝化及反硝化潜力沿水流方向的变化规律.结果表明,中游底泥硝化潜力最大,为4.76×10^-6 g/(g·h);上游底泥反硝化潜力最大,为8.1×10^-7 g/(g·h);底泥中亚硝酸菌的密度分布与硝化潜力的分布一致.结果还表明,提高HBFM系统氮去除能力的关键在于改变硝化反硝化区域分布,从而提高系统的反硝化能力.     

Technological feasibility and costs of achieving a 50 % reduction of global GHG emissions by 2050: mid- and long-term perspectives

In this article we examine the technological feasibility of the global target of reducing GHG emissions to 50 % of the 1990 level by the year 2050. We also perform a detailed analysis of the contribution of low-carbon technologies to GHG emission reduction over mid- and long-term timeframes, and evaluate the required technological cost. For the analysis we use AIM/Enduse[Global], a techno-economic model for climate change mitigation policy assessment. The results show that a 50 % GHG emission reduction target is technically achievable. Yet achieving the target will require substantial emission mitigation efforts. The GHG emission reduction rate from the reference scenario stands at 23 % in 2020 and 73 % in 2050. The marginal abatement cost to achieve these emission reductions reaches 150/tCO < sub > 2 < /sub > -eq in 2020 and150/tCO₂-eq in 2020 and 600/tCO₂-eq in 2050. Renewable energy, fuel switching, and efficiency improvement in power generation account for 45 % of the total GHG emission reduction in 2020. Non-energy sectors, namely, fugitive emission, waste management, agriculture, and F-gases, account for 25 % of the total GHG emission reduction in 2020. CCS, solar power generation, wind power generation, biomass power generation, and biofuel together account for 64 % of the total GHG emission reduction in 2050. Additional investment in GHG abatement technologies for achieving the target reaches US6.0 trillion by 2020 and US 6.0 trillion by 2020 and US 73 trillion by 2050. This corresponds to 0.7 and 1.8 % of the world GDP, respectively, in the same periods. Non-Annex I regions account for 55 % of the total additional investment by 2050. In a sectoral breakdown, the power generation and transport sectors account for 56 and 30 % of the total additional investment by 2050, respectively.     

Source-specific sewage pollution detection in urban river waters using pharmaceuticals and personal care products as molecular indicators

Environmental Science and Pollution Research - Source-specific elucidation of domestic sewage pollution caused by various effluent sources in an urban river water, as conducted for this study,...     

Feasibility investigation on a dual waste-plastics recycling system concept

Fiber-reinforced plastics (FRP) were first used as a material for boats and bath tubs about 40 years ago. Because of their great durability, wastes including FRP products are increasing. In addition, since the FRP resin is synthesized from expensive reactants, material recycling is highly desirable. Recycling using supercritical water is one solution; however, the cost of producing the high pressure and temperature needed to produce supercritical water prevents the concept from being realized. Therefore, we proposed a system concept based on dual waste-plastics recycling. A numerical survey of the results confirmed that our concept was feasible and would contribute to resource recycling as we expected. Received: January 6, 1998 / Accepted: July 23, 1999