Impact of carbon source on nitrous oxide emission from anoxic/oxic biological nitrogen removal process and identification of its emission sources

Wastewater treatment is an important source of nitrous oxide (N₂O), which is a strong greenhouse gas and dominate ozone-depleting substance. The purpose of this study was to evaluate the effect of carbon source on N₂O emission from anoxic/oxic biological nitrogen removal process. The mechanisms of N₂O emission were also studied. Long-term experiments were operated to evaluate the effect of three different carbon sources (i.e., glucose, sodium acetate, and soluble starch) on N₂O emission characteristics. And batch experiments, in the presence or absence of specific inhibitors, were carried out to identify the sources of N₂O emission. The ammonia-oxidizing bacteria (AOB) and denitrifiers community compositions under different circumstances were also analyzed based on which the underlying mechanisms of N₂O emission were elucidated. The conversion ratios of N₂O in reactors with glucose, sodium acetate, and soluble starch were 5.3 %, 8.8 %, and 2.8 %, respectively. The primary process responsible for N₂O emission was nitrifier denitrification by Nitrosomonas-like AOB, while denitrification by heterotrophic denitrifiers acted as the sink. Reactor with sodium acetate showed the highest N₂O emission, together with the highest nitrogen and phosphate removal ratios. Carbon source has a significant impact on N₂O emission quantity and relatively minor effect on its production mechanism.     

An integrated method for safety pre-warning of complex system

In large-scale and complex industrial systems, unplanned outages and hazardous accidents cause huge economic losses, environmental contamination, and human injuries, due to component degradation, exogenous changes, and operational mistakes. In order to ensure safety and increase operational performance and reliability of complex system, this study proposes an integrated method for safety pre-warning to analyze the current safety state of each component and the whole system indicating hidden hazards and potential consequence, and furthermore predict future degradation trends in the long term.The work presented here describes the rationale and implementation of the integrated method incorporating HAZOP study, degradation process modeling, dynamic Bayesian network construction, condition monitoring, safety assessment and prognosis steps, taking advantage of the priori knowledge of the interactions and dependencies among components and the environment, the relationships between hazard causes and effects, and the use of historical failure data and online real-time data from condition monitoring.The application of the integrated safety pre-warning approach described here to the specific example of the gas turbine compressor system demonstrates how each phase of the presented method contributes to completion of the safety pre-warning system development in a systematic way.     

Water washing effects on metals emission reduction during municipal solid waste incinerator (MSWI) fly ash melting process

This study investigated that water washing effects on the metals emission reduction in melting of municipal solid waste incinerator (MSWI) fly ash. Experimental conditions were conducted at liquid-to-solid (L/S) ratio 10, 20, and 100 for water-washing process and its subsequent melting treatment at 1450 °C for 2 h. The simple water-washing process as a pre-treatment for MSWI fly ash can remove most of the chlorides, leachable salts, and amphoteric heavy metals from the MSWI fly ash, resulting in the washed ash having lowered chlorine content. MSWI fly ashes washed by L/S ratio 10 and above that were melted at 1450 °C produced slag containing relatively high vitrificaton ratio of Cu and Pb. Besides, the vitrification ratios of Na, K, Ca, and Mg in washed MSWI fly ash were also higher than that of MSWI fly ash. The results indicated that washed MSWI fly ash can reduce the emission of metallic chlorides during its subsequent melting treatment.     

建设项目环境影响的医学评价方法研究

作者在对中国我人民解放军第４７医院病建项目所产生的大气环境影响进行了医学秤价和影响，并在预测的基础上，建立了完整的环境医学影响廉政价方法，由于该评价方法完全尊循了国内现行大气环境影响评价的基本要求和程序，因此，它在今后的环境影响医学评价中净有广泛的应用。     

建立城市自然灾害承灾能力指标的思路探讨

本文论述了城市承灾能力的含义，分析了我国城市主要自然灾害以及承文体的类型和致灾因素，探讨了城市承灾能力指标，为城市承灾能力综合评判提供了依据．     

AAS与ICP－AES间接测定天然水中硫酸盐

本文以与过量形成ＢａＳＯ＿４沉淀反应为基础，较详细地讨论了反应条件、从而拟定了用ＡＡＳ和ＩＣＰ－ＡＥＳ间接测定天然水中的方法、确定了方法的精密度，ＡＡＳ法的ＲＳＤ％为１．５，ＩＣＰ－ＡＥＳ法为３．２．两种方法对比分析的结果接近，误差为１．０％（相对）。用于天然水中的测定，获得满意的结果。     

顺倾山体采空侧滑致灾的复合应力场研究

本文分析了地下采空情况后认为，山体采空侧动，软弱夹层为决定性条件；其变动范围、速率、规模与性质，与地下采空有关的复合应力场有关。经对观测资料分析、仿真模型试验与仿真数值模拟的对比研究，揭露了顺倾山体的“复合临空面”条件下，“复合变动”的“复合应力场”。     

干燥过程中的噪声危害及防治措施

粮食烘干过程的噪声危害必须引起人们的重视，通过对噪声产生的根源及给作业人员健康带来的损害进行分析，结合生产实际，提出了防治措施。     

攀钢烧结烟气脱硫技术研究

介绍了攀钢烧结烟气的特点，SO2的来源。根据国内外烟气脱硫技术现状， 提出了攀钢烧结烟气脱硫的技术要求。     

充分利用水资源 改善生态环境

本文结合攀枝花地区实际,论述了水资源利用率高低是影响经济发展和改善生态环境的重要因素,调查分析了攀枝花地区水资源利用率低的原因;提出了提高水资源利用率的对策和措施。为促进经济发展和改善生态环境提供了依据。