从一起爆炸事故谈作业安全票证(单)的管理

从一起爆炸事故的原因--没有办理设备检修许可证,分析了使用作业安全票证(单)存在的问题,提出了加强作业安全票证(单)管理措施.     

种植苜蓿草的生态环境效益和经济效益分析——苜蓿草在台安县洪家农牧场种植实验

2004年台安县洪家农牧场引进加拿大优质苜蓿草进行种植实验.通过清种、林地间作和不种苜蓿草对比实验,对土壤速效氮、速效磷、速效钾、有机质、PH值、含水量进行分析,得出种植苜蓿草所产生的生态环境效益和经济效益.此项实验结论说明,紫色苜蓿是牧草之王,可促进养殖业的发展,对改善生态环境,防止土壤沙化和水土流失,改善农业结构,实现生态良性循环起到积极的促进作用,对改善生态环境起到了良好的示范作用.     

T-RFLP方法分析城市污水处理厂中细菌群落的动态变化

采用基于16SrRNA基因的末端限制性片段长度多态性技术(T-RFLP),分析了功能稳定的2个城市污水处理系统中(系统A及系统B),细菌群落结构在105d中的动态变化.在研究中,系统A和系统B功能稳定,BOD出水浓度均在8mg/L左右,总氮(TN)出水浓度分别在25mg/L和23mg/L之下.T-RFLP图谱分析表明,系统A中,115、118、123、471、482和835bp等T-RFs的相对丰度变化显著,系统B中,123、471、750和835bp等T-RFs的相对丰度变化显著.移动窗口分析表明,系统A中细菌群落的平均变化率Δt(15d)为21.5%±5.7%,系统B的平均变化率Δt(15d)为22.6%±5.0%.洛伦兹曲线分析表明,系统A中20%的微生物的累积相对丰度为43%～50%;系统B中20%的微生物的累积相对丰度为47%～52%.结果表明,在城市污水处理厂中,稳定的功能并没有藕联着稳定的细菌群落结构.     

潮汐流人工湿地低温下 NH4+ -N去除模型的比较和优化

针对目前人工湿地在低温条件下脱氮效能降低的问题,本研究对每天3个运行周期的潮汐流人工湿地在低温条件下对NH4+ -N的处理效能进行研究,同时利用表观动力学模型、多元参数回归模型及Monod机制模型对NH4+-N的去除过程进行拟合.结果显示,在平均水温为9～13℃条件下,每天3个运行周期的潮汐流人工湿地对NH4+-N有良...     

企业风险管理与经营效率：来自中国保险业的经验证据

本文从风险管理的视角对企业效率评估的数据包络分析技术进行了改进,探讨了风险管理与经营效率的内在关联,并以中国保险业为例,对1999年以来企业真实的经营效率水平进行了评估。结果表明：企业内部的风险管理能力对其经营效率水平的提升具有明显的影响,而且这种影响力正在逐渐加强。不考虑企业内部的风险管理水平将直接导致其经营效率的测算结果出现低估,2002年以后这种低估的程度越发明显,这可归因于同期保险企业开始逐渐重视提高自身的风险管理能力。以上结论也为企业如何在管控风险的同时提升经营效率水平提供了有价值的指导。     

提高生产过程安全联锁系统可靠性的实用技术

以聚醚车间雾化器的安全联锁和工业蒸汽锅炉汽包的安全联锁两个实例,介绍了在安全性要求比较高的中、小型生产装置中,以较少的投资提高安全联锁系统可靠性的实用方法.这种基于冗余技术思想的实用安全技术,适用于石油化工生产过程及其它一些生产领域.     

钢渣处理技术的环境性能比较

随着钢铁工业的快速发展,大量钢渣弃置堆积,不仅成为环境污染源,而且占用大量的土地。目前钢渣处理技术较多,其中主要的处理方法有冷弃法、热闷法、热泼法、浅盘法、水淬法、风淬法等。本研究采用生命周期评价方法,对主要钢渣处理技术进行评估,定义了生命周期评估边界和清单指标,建立了清单计算模型,得到了不同钢渣处理技术的生命周期清单。为了提高结果的可信性,对模型进行了不确定性分析。结果表明滚筒法和风淬法的环境性能较好,是值得推广的钢渣处理技术。     

四川某中小城镇污水处理厂进水水质统计分析

生活污水水质对处理工艺的选择、设计参数的选取以及稳定运行十分重要。运用SPSS软件,对四川某中小城镇污水处理厂为期一年的进水指标(水量、COD、氨氮、总磷、pH、SS)进行方差和相关性分析。方差分析结果显示进水量、氨氮和SS在月份和季节之间存在显著性差异,而总磷和pH仅在月份之间存在显著差异,COD在季度和月份之间无显著性差异;指标相关性分析表明,进水量和氨氮之间呈负相关,氨氮和总磷、COD和总磷之间呈正相关,且相关性显著。在此分析的基础上对污水处理厂设计、工艺选择及运行管理提出了一些建议。     

Effect of platinum on the photocatalytic degradation of chlorinated organic compound

TiO2 nanoparticles, doped with di erent Pt contents, were prepared by a modified photodeposition method using Degussa P-25 TiO2, H2PtCl6 6H2O and methanol as the solvents. The physicochemical properties of Pt/TiO2 were investigated by the nitrogen adsorption and desorption isotherm measurement technique, X-ray di raction analysis and photoluminescence spectra, respectively. Reaction rates from photocatalytic removal of dichloromethane over Degussa P-25 TiO2 and Pt/TiO2 were evaluated. The average diameter and BET surface area of the TiO2 catalyst particles were 300 nm and 50 m2/g, respectively. The degradation e ciency was 99.0%, 82.7%, 55.2%, and 57.9% with TiO2 at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. And the degradation e ciency was 99.3%, 79.7%, 76.5%, and 73.4% with a 0.005 wt.% Pt/TiO2 at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. In addition, we found that the photoluminescence emission peak intensities decreased with increases in the doping amount of Pt, which indicates that the irradiative recombination was weakened. Furthermore, the results showed that the UV/0.005 wt.% Pt/TiO2 process was capable of e ciently decomposing gaseous DCM in air.     

Methanotrophic community structure of aged refuse and its capability for methane bio-oxidation

Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation for methane. Specially, community structure and methane oxidation capability of methanotrophs in the aged refuse were studied. The amount of methanotrophs ranged 61.97 103–632.91 103 cells/g (in dry basis) in aged refuse from Shanghai Laogang Landfill. Type I and II methanotrophs were found in the aged refuse in the presence of sterilized sewage sludge and only Type I methanotrophs were detected in the presence of nitrate minimal salt medium (NMS). The clone sequences of the pmoA gene obtained from the aged refuse were similar to the pmoA gene of Methylobacter, Methylocaldum, and Methylocystis, and two clones were distinct with known genera of Type I methanotrophs according to phylogenetic analysis. Aged refuse enriched with NMS was used for methane biological oxidation and over 93% conversions were obtained.