桔柑隧道进口段塌方原因分析与处理措施

通过对桔柑隧道进口浅埋段塌方前掌子面的状态与前期施工工序的追溯,详细分析了隧道塌方前出现的各种征兆,并对其塌方机理进行了分析与计算,提出了较为有效的解决初喷混凝土在涌水量较大的情况下与岩壁的结合问题,以及如何选择隧道开挖方式、对大断面铁路隧道穿越浅埋段的处理方案,并最终成功穿越该段,为类似工程提供了借鉴。     

2007年5-6月国内环境事件

简要统计了2007年5-6月国内发生的各种环境事件123起,包括沙尘天气10起,污染事件23起,地震15起,山体滑坡和泥石流13起,旱灾5起,以及其他自然灾害57起.对自然灾害进行了讨论.     

地表UV-B辐射增强对土壤-冬小麦系统呼吸速率和N2O排放的影响

通过室外盆栽实验,用静态箱-气相色谱法测定土壤-冬小麦系统的呼吸速率和N₂O排放通量,研究了UV-B辐射增强20%对土壤-冬小麦系统的呼吸速率和N₂O排放的影响.结果表明,相同的气象条件和田间管理下,UV-B辐射增强处理对呼吸速率和N₂O排放的季节变化模式无明显影响.在返青期,UV-B辐射增强显著降低了土壤-冬小麦系统的呼吸速率,但对N₂O的排放通量没有产生显著影响;在拔节孕穗期,UV-B辐射增强处理显著降低了土壤-冬小麦系统的呼吸速率和N₂O的排放通量;在抽穗-成熟期,UV-B辐射增强处理对土壤-冬小麦系统的呼吸速率和N₂O的排放没有显著影响.返青-齐穗期,UV-B增强处理显著降低土壤-冬小麦系统的N₂O累积排放量;但从齐穗开始至小麦成熟,UV-B增强处理对土壤-冬小麦系统的N₂O累积排放量没有显著影响.     

沸石强化生化装置脱氮功能的效果及机理初探

针对石化工业废水开展沸石强化脱氮处理试验研究,通过比较沸石浓度25mg/L与空白,以及沸石浓度25 mg/L与50mg/L两阶段脱氮效果,探讨沸石促进脱氮功能的机理,结果表明,曝气池中投加沸石可明显提高氨氮和总氮的去除率,硝化细菌总数和硝化功能也得到增强。与空白对照组相比, 沸石浓度25mg/L的试验组运行稳定后,氨氮去除率提高约10%~13%,总氮去除率约提高13%,出水中NO3--N含量约提高100%,氨氮与总氮之比下降6%,内源硝化耗氧呼吸速率可提高138%,硝化细菌总数是空白对照组2.2folds。沸石浓度提高到50mg/L后,试验组的脱氮效果略有增加,但效果不明显。通过对试验结果的关联分析,认为沸石提高系统脱氮能力的原因一方面是因为沸石对NH4+及硝态氮的交换吸附,另一方面NH4+离子富集于沸石表面及内部、沸石颗粒独特的好氧-缺氧微环境,以及沸石离解出CO32- 或HCO3-增加碱度等条件,促进了硝化细菌和反硝化细菌的生长,从而提高了系统脱氮能力。     

土壤中多环芳烃的SPMD辅助解吸行为研究

为了开发一种表征土壤中憎水性有机污染物解吸及生物有效性的新方法,建立了半透膜被动采样装置（SPMD）研究土壤中有机污染物解吸行为的方法,利用SPMD分析了多环芳烃菲、芘和苯并［a］芘在3种不同性质土壤中的辅助解吸行为.结果表明,SPMD是一种很好地表征土壤中憎水性有机污染物解吸及生物有效性的手段. SPMD辅助解吸多环芳烃的效率与土壤有机质及多环芳烃性质有关.随着土壤有机质含量的降低,土壤中菲和芘的SPMD解吸率逐渐升高,对于10 mg/kg染毒水平,当土壤有机质含量由18.68%降低到0.3%时,2种化合物的解吸率分别由56.45%和48.28%上升到接近100%;但是对于苯并［a］芘,粘土表现出明显的滞留能力,在有机质含量（0.3%）很低、粘土含量（39.05%）较高的3号土壤中,苯并［a］芘的解吸率仅有66.97%.不同多环芳烃SPMD辅助解吸率差别很大,随着土壤有机质含量的降低,以及污染物浓度的提高,菲和芘的解吸差异逐渐缩小,而苯并［a］芘与上述2种多环芳烃的差异很大,主要是由于苯并［a］芘具有高度亲脂性,并且分子较大,造成其容易滞留在粘土的微孔及有机质的致密结构中.     

Experimental investigation of the e ect of flow turbulence and sediment transport patterns on the adsorption of cadmium ions onto sediment particles

The mechanism of flow turbulence,sediment supply conditions,and sediment transport patterns that affect the adsorption of cadmiumions onto sediment particles in natural waters are experimentally simulated and studied both in batch reactors and in a turbulencesimulation tank.By changing the agitation conditions,the sediment transport in batch reactors can be categorized into bottom sediment-dominated sediment and suspended sediment-dominated sediment.It is found that the adsorption rate of bottom sediment is much lessthan that of suspended sediment,but the sediment transport pattern does not affect the final(equilibrium)concentration of dissolvedcadmium.This result indicates that the parameters of an adsorption isotherm are the same regardless of the sediment transport pattern.Inthe turbulence simulation tank,the turbulence is generated by harmonic grid-stirred motions,and the turbulence intensity is quantifiedin terms of eddy diffusivity,which is equal to 9.84F(F is the harmonic vibration frequency)and is comparable to natural surfacewater conditions.When the turbulence intensity of flow is low and sediment particles stay as bottom sediment,the adsorption rateis significantly low,and the adsorption quantity compared with that of suspended sediment is negligible in the 6 h duration of theexperiment.This result greatly favors the simplification of the numerical modeling of heavy metal pollutant transformation in naturalrivers.When the turbulence intensity is high but bottom sediment persists,the rate and extent of descent of the dissolved cadmiumconcentration in the tank noticeably increase,and the time that is required to reach adsorption equilibrium also increases considerablydue to the continuous exchange that occurs between the suspended sediment and the bottom sediment.A comparison of the results ofthe experiments in the batch reactor and those in the turbulence simulation tank reveals that the adsorption ability of the sediment,andin particular the adsorption rate,is greatly over-estimated in the batch reactor.     

Kinetics of selective catalytic reduction of NO by NH3 on Fe-Mo/ZSM-5 catalyst

The catalyst of Fe-Mo/ZSM-5 has been found to be more active than Fe-ZSM-5 and Mo/ZSM-5 separately for selective catalytic reduction (SCR) of nitric oxide (NO) with NH3. The kinetics of the SCR reaction in the presence of O2 was studied in this work. The results show that the observed reaction orders were 0.74-0.99, 0.01-0.13, and 0 for NO, O2 and NH3, respectively, at 350-450℃. And the apparent activation energy of the SCR was 65 kJ/mol on the Fe-Mo/ZSM-5 catalyst. The SCR mechanism was also deduced. Adsorbed NO species can react directly with adsorbed ammonia species on the active sites to form N2 and H2O. Gaseous O2 might serve as a reoxidizing agent for the active sites that have undergone reduction in the SCR process. It is also important to note that a certain amount of NO was decomposed directly over the Fe-Mo/ZSM-5 catalyst in the absence of NH3.     

环境友好城市建设初探——以上海为例

文章试图在可持续发展思想的引导下,运用"环境友好"的理念,研究和阐述了"环境友好城市"的内涵。并以上海为例,提出了环境友好城市的发展目标和建设方向,选用构建指标体系的方式,对城市的环境友好程度进行评估,提出了推进和实施环境友好城市建设的保障措施体系。     

橡胶工业化学品安全防护

随着对环境、安全和健康意识的加强,人们对于工作场所的安全卫生问题已引起极大的关注.众所周知,橡胶工业对工人的健康存在较大的危害,这主要是在橡胶工业中所采用的大量化学品导致的.本文将就橡胶工业化学品的危害和安全防护的问题进行简要介绍和探讨.     

装置级突发事故应急预案编制的思考与对策

结合石化企业装置生产特点,分析装置级突发事故应急预案编制中存在的不足和问题,并对应急预案编制的思路和处置对策进行了深入地探讨.