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51.
A pilot-scale multilevel contact oxidation reactors system, coupled with saran lock carriers,was applied for the treatment of poultry farm wastewater. The removal efficiencies of CODcr, ammonia, and the total nitrogen as well as the elimination performance of CODcr and total nitrogen along the three-level contact oxidation tanks under six designed operational models were investigated. Based on the performance of the nitrogen removal of the saran lock carriers and the distribution of anoxic–aerobic interspace under the suitable operation model, the mechanism of nitrogen removal of the system was also explored. The results revealed that the intermittent aeration under parallel model is the most suitable operation model, while the removal efficiencies of CODcr, ammonia, and the total nitrogen were 86.86%, 84.04%, and 80.96%, respectively. The effluent concentration of CODcr,ammonia, and the total nitrogen were 55.6 mg/L, 8.3 mg/L, and 12.0 mg/L, which satisfy both the discharge standard of pollutants for livestock and poultry breeding industry(GB18596–2001) and the first grade of the integrated wastewater discharge standard(GB 8978–1996). Moreover, the mechanism for the nitrogen removal should be attributed to the plenty of anoxic–aerobic interspaces of the biofilm and the three-dimensional spiral structure of the saran lock carriers, where the oxygen-deficient distribution was suitable for the happening of the simultaneous nitrification and denitrification process. Therefore, the multilevel contact oxidation tanks system is an effective pathway for the treatment of the poultry farm wastewater on the strength of a suitable operation model and novel carriers.  相似文献   
52.
OBIA与RF结合的龙口市土地利用信息提取方法   总被引:1,自引:0,他引:1  
为提高中分辨率遥感影像解译精度,本文提出面向对象影像分析(Object Based Image Analysis,OBIA)与随机森林(Random Forest,RF)结合的土地利用信息提取方法。采用Landsat 8 OLI影像,针对不同地物特点,阈值分割和多尺度分割结合创建影像对象,规则集和分类器协同分类,基于Relief F算法分别对光谱特征、纹理特征及所有特征降维筛选特征子集,并与全部特征一起应用RF建模,对龙口市进行土地利用信息提取与比较。结果表明:OBIA与RF结合提取土地利用信息,基于Relief F算法筛选纹理特征,保留完整光谱、几何、空间关系特征构建RF模型,建模错分率为0.0958,分类总体精度和Kappa系数分别为89.37%和0.872,取得较理想结果。该方法可应用于中分辨率遥感影像土地利用信息提取。  相似文献   
53.
企业环保设施市场化运营瓶颈的经济博弈分析   总被引:3,自引:0,他引:3  
从经济学角度构建了企业环境污染的理论模型。并运用制度经济学与博弈论原理揭示我国企业环境污染行为与企业环保设施市场化运营瓶颈的内在原因,据此给出制度改革的有效建议。  相似文献   
54.
Genuine saving measures the real change in0 total wealth, factoring in the depreciation of produced assets, depletion of natural resources, pollution damages, and expenditures on education. This paper presents a theoretical framework for measuring changes in wealth in total and per capita terms, establishes the link between savings measures and prospects for social welfare, and provides summary empirical estimates of the savings measures. China excepted, the majority of countries below median income are distinguished by apparent declines in total wealth per capita.  相似文献   
55.
Total and particulate metal concentrations, measured during intensive synoptic studies of the Genesee River, NY, correlated with suspended-sediment concentration and river discharge. Dissolved metal concentrations, on the other hand, showed little systematic variation over the length of the river. Metal and sediment fluxes for two elevated-discharged periods peaked at a midbasin sampling site. For most metals at most sampling sties particulate materials comprised over one-half of the total material. Comparison of particulate material metal concentrations, normalized to the measured suspended-sediment concentrations had with basinwide average values shows that sites having low suspended-sediment concentrations had high particulate material metal contents relative to the basin averages, while sites with high suspended-sediment concentration had low metal contents. These results are consistent with a metal transport mechanism in the Genesee River involving (1) a nearly constant dissolved component, (2) a fine acid-soluble component, and (3) a coarse component that is effectively a neutral diluent in the sediment. Chemical factors, such as sediment organic content, also appear to affect metal transport in the Genesee River.  相似文献   
56.
The model of spatial distribution of main forest soil groups in Croatia was developed as a function of basic pedogenetic factors: lithological substratum, macroclimate and relief. Used data about soil group, lithological substratum, terrain slope and aspect were collected on 1881 soil profiles. Macroclimatic data were estimated for each soil profile by spatial interpolation between meteorological stations. Feedforward neural networks were used as modelling tool. The final model has total classification correctness of 63.5% for training data set and 62.3% for independent test data set. The best result (86.4%) was achieved for fluvisols which are strongly spatially correlated with alluvial sediment in a flood plains. The worst result was achieved for luvisol (14.2%) which mainly comprised very old soils, probably developed under pedogenetic factors different from actual. The model was applied on entire Croatian territory aiming at construction of potential spatial distribution of main forest soils (without human impact), which was compared by the potential spatial distribution of major forest types modelled independently.  相似文献   
57.
ABSTRACT: Observed April 1 snowpack accumulations within and near the Gunnison River basin in southwestern Colorado are compared with simulations from the Rhea-orographic-precipitation model to determine if the model simulates reliable magnitudes and temporal and spatial variability in winter precipitation for the basin. Twenty simulations of the Rhea model were performed using‘optimal’parameter sets determined for 10-kilometer (km) grids (10-km by 10-km grid cells) through stochastic calibration. Comparisons of Rhea-model simulations of winter precipitation with April 1 snowpack accumulations at 32 snowcourse stations were performed for the years 1972–1990. For most stations and most years the Rhea model reliably simulates the temporal and spatial variability in April 1 snowpack accumulations. However, in general, the Rhea-model underestimates April 1 snowpack accumulations in the Gunnison River basin area, and the underestimation is greatest for locations that receive the largest amount of snow. A significant portion of the error in Rhea-model simulations is due to the calibration of the Rhea model using gauge-catch precipitation measurements which can be as much as 50 percent below actual snowfall accumulations. Additional error in the Rhea-model simulations is a result of the comparison of gridded precipitation values to observed values measured at points.  相似文献   
58.
美国环境与健康管理体制借鉴   总被引:1,自引:1,他引:0       下载免费PDF全文
美国为应对环境污染带来的公共健康灾难,建立了环保局与卫生部既分工又协作的体制,两个部门都关注环境污染对人类健康的危害。在职能上,环保局侧重于管制和"污染者",卫生部侧重于服务和"潜在受害者"。联邦层面,环保局与卫生部在管制方面和研究(信息共享)方面紧密合作。地方层面,环保局的主要职能是监督各州执行联邦标准,卫生部的主要职能是提供健康和医疗服务,并在具体工作中密切配合。借鉴美国的经验教训,明确建立"公众健康优先"的环境管理价值取向,针对环境与健康风险管理的特点推进生态环境统一监管机构改革,以法治思维和法治方法推进环境与健康治理体系建设;加强科学研究,加快建设环境与健康风险控制信息系统。  相似文献   
59.
Behind humanitarian assistance and disaster relief (HADR) efforts are governance networks of actors working together to facilitate, coordinate, and deliver joint aid and response initiatives. Militaries are key stakeholders in these networks because of their unique capabilities, particularly in Southeast Asia. This paper explores the role of military governance networks in shaping HADR affairs. It presents a framework for examining military-to-military relational structures in humanitarian and disaster contexts using network theory and social network analysis. It also assesses the nature of military ties and their influence on two capability areas essential to humanitarian activities in the region: (i) the distribution of military assets and equipment used in HADR; and (ii) the coordination of HADR exercises and training. This paper seeks to provide insights into how governance network features and properties affect the capacity of ASEAN (Association of Southeast Asian Nations) militaries to use available resources efficiently and to achieve shared objectives in regional disaster response.  相似文献   
60.
The current risk management approach for the Norwegian offshore petroleum industry came into effect in 2001 and has been stable with minor changes for 15 years. Relatively few new installations were slated for development until quite recently, and several new projects have been started in the last few years. The paper considers the risk management approach in the pre-FEED phase and builds on two case studies selected from the most recent cases. These case studies have been evaluated with respect to how uncertainties are considered in the early phase, based on the submission of the Plan for Development and Operation, their evaluations by authorities and the supporting documents. Both case studies involve new concepts for which there is no experience from similar environments and/or water depths. In spite of what could have been expected, the case studies conclude that uncertainties have not been in focus at all during concept development. This appears to be definitely the case for the licensees, but also to be the case for the authorities. Some suggestions are presented for what could have been considered by the licensees and authorities.  相似文献   
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