Microbial response to CaCO3 application in an acid soil in southern China

Calcium carbonate (CaCO₃) application is widely used to ameliorate soil acidification. To counteract soil and bacterial community response to CaCO₃ application in an acidic paddy soil in southern China, a field experiment was conducted with four different dosages of CaCO₃ addition, 0, 2.25, 4.5 and 7.5?tons/ha, respectively. After one seasonal growth of rice, soil physicochemical properties, soil respiration and bacterial communities were investigated. Results showed that soil pH increased accordingly with increasing dose of CaCO₃ addition, and 7.5?tons/ha addition increased soil pH to neutral condition. Moderate dose of CaCO₃ application (4.5?tons/ha) significantly increased soil dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) content, enhanced soil respiration, while the excessive CaCO₃ application (7.5?tons/ha) decreased these soil properties. High-throughput sequencing results illustrated that moderate dose of CaCO₃ application increased the richness and alpha diversity of soil bacterial community. Compared with control, the relative abundance of Anaerolineaceae family belonging to Chloroflexi phylum increased by 38.7%, 35.4% and 24.5% under 2.25, 4.5 and 7.5?tons/ha treatments, respectively. Redundancy analysis (RDA) showed that soil pH was the most important factor shaping soil bacterial community. The results of this study suggest that proper dose of CaCO₃ additions to acid paddy soil in southern China could have positive effects on soil properties and bacterial community.     

BiOCl/SiO2/Fe3O4复合材料可见光催化去除水中亚甲基蓝

以FeCl_3·6H_2O、FeCl_2·4H_2O、(C_2H_5)_4SiO_4、Bi(NO_3)_3·5H_2O、KCl为主要原料,采用化学共沉淀法和水热法制备了BiOCl/SiO_2/Fe_3O_4光催化剂,并对其进行EDS、TEM、XRD、FT-IR、UV-Vis表征,最后通过亚甲基蓝降解实验,研究了催化剂在合成过程中pH及催化剂投加量对其光催化性能的影响.结果表明,在pH=6、催化剂初始投加量为0.5 g·L~(-1)时,对亚甲基蓝的可见光催化效果最佳,光照120 min后对10 mg·L~(-1)的亚甲基蓝溶液的脱色率达到93.2%.BiOCl/SiO_2/Fe_3O_4经过简单的无水乙醇和水洗后,可高效重复利用4次.综合表明,BiOCl/SiO_2/Fe_3O_4是一种在处理染料废水中具有应用前景的磁性光催化剂.     

Simultaneous quantification of fifty-one odor-causing compounds in drinking water using gas chromatography-triple quadrupole tandem mass spectrometry

A wide range of compounds with various structural features can cause taste and odor(TO)problems in drinking water. It would be desirable to determine all of these compounds using a simple analytical method. In this paper, a sensitive method combining liquid–liquid extraction(LLE) with gas chromatography-triple quadrupole tandem mass spectrometry(GC–MS/MS)was established to simultaneously analyze 51 odor-causing compounds in drinking water,including organic sulfides, aldehydes, benzenes, phenols, ethers, esters, ketones, nitrogenous heterocyclic compounds, 2-methylisoborneol and geosmin. Three deuterated analogs of target analytes, dimethyl disulfide-d6, benzaldehyde-d6 and o-cresol-3,4,5,6-d4,were used to correct the variations in recovery, and five isotope-labeled internal standards(4-chlorotoluene-d4, 1, 4-dichlorobenzene-d4, naphthalene-d8, acenaphthene-d10, phenanthrene-d10 respectively) were used prior to analysis to correct the variations arising from instrument fluctuations and injection errors. The calibration curves of the target compounds showed good linearity(R2 0.99, level = 7),and method detection limits(MDLs) below 1/10 of the odor threshold concentrations were achieved for most of the odorants(0.10–20.55 ng/L). The average recoveries of most of the analytes in tap water samples were between 70% and 120%, and the method was reproducible(RSD 20%, n = 7). Additionally, concentrations of odor-causing compounds in water samples collected from three drinking water treatment plants(DWTPs) were analyzed by this method.According to the results, dimethyl trisulfide, dimethyl disulfide and indole were considered to be the key odorants responsible for the swampy/septic odor. 2-Methylisoborneol and geosmin were detected as the main odor-causing compounds for musty/earthy odor in DWTP B.     

污染物在下包气带非饱水条件下迁移转化的研究

一、前言 城市污水施于农田,其中的污染物可能潜入地下水中造成危害,为了控制这种现象的发生,有必要开展污染物在地下包括下包气带的迁移转化规律研究,以供制订有关标准的依据。     

城市生活垃圾堆肥对水稻生长和土壤的影响

利用城市生活垃圾堆肥作为肥料,采用水培法和土培法对水稻生长和土壤的影响进行了试验研究。结果表明,施用城市生活垃圾堆肥明显提高了水稻的生长量,增加了水稻植株茎叶中硅的含量;降低了糙米中有毒元素镉的含量;改变了土壤的酸度,增强了土壤的肥力;水稻植株和土壤中某些有害元素的含量略有增加,但远低于环境的允许值。     

城市合流污水A２/O处理系统中TTC ETS活性监测研究

研究了温度和F/M的变化对A^２/O系统TTCETS活性的影响,分析了TTCETS活性与COD降解的相关关系;通过低C/N冲击下TTCETS活性和理化指标的比较,讨论了以TTCETS活性表征系统运行状况的优劣.结果表明,一定范围内,温度与F/M均与TTCETS活性成正相关,TTCETS活性(TF/TSS·t)变化范围约13.2～48.3 mg/(g·h),最大值约为60 mg/(g·h);TTCETS活性与COD去除率相关性显著,并且TTCETS活性可预警系统的异常状态,当TTCETS活性为41.0 mg/(g·h)时,COD去除效率最高.     

香料生产废水的生化处理研究

某合成洋茉莉醛香料厂的生产废水中含有香料、香料副产品、降解物以及原辅材料,具有CODcr浓度高、水质波动大以及水中污染物成分复杂等特点,属于典型的高浓度难降解有机废水,而该厂现有的废水处理工艺不仅流程长、费用高且出水难以达到GB8978—1996一级排放标准。本文采用活性污泥法及MBR工艺研究了洋茉莉醛香料废水的处理效果及其影响因素,并结合GC—MS对降解产物进行了分析。试验结果表明：采用本文方法对洋茉莉醛香料废水有较好的降解作用,可经较少的步骤处理实现达标排放。     

Regional crop yield, water consumption and water use efficiency and their responses to climate change in the North China Plain

The North China Plain (NCP) is one of the most important regions for food production in China, with its agricultural system being significantly affected by the undergoing climate change and vulnerable with water stress. In this study, the Vegetation Interface Processes (VIP) model is used to evaluate crop yield, water consumption (ET), and water use efficiency (WUE) of a winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) double cropping system in the NCP from 1951 to 2006. Their responses to future climate scenarios of 21st century projected by the GCM (HadCM3) with Intergovernmental Panel on Climate Change Special Report on Emission Scenario (IPCC SRES) A2 and B1 emissions are investigated. The results show a rapid enhancement of crop yield in the past 56 years, accompanying with slight increment of ET and noticeable improvement of WUE. There exist spatial patterns of crop yield stemmed mainly from soil quality and irrigation facilities. For climate change impacts, it is found that winter wheat yield will significantly increase with the maximum increment in A2 occurring in 2070s with a value of 19%, whereas the maximum in B1 being 13% in 2060s. Its ET is slightly intensified, which is less than 6%, under both A2 and B1 scenarios, giving rise to the improvement of WUE by 10% and 7% under A2 and B1 scenarios, respectively. Comparatively, summer maize yield will gently decline by 15% for A2 and 12% for B1 scenario, respectively. Its ET is obviously increasing since 2050s with over 10% relative change, leading to a lower WUE with more than 25% relative change under both scenarios in 2090s. Therefore, possible adaptation countermeasures should be developed to mitigate the negative effects of climate change for the sustainable development of agro-ecosystems in the NCP.     

汶川地震期间天津地震前兆台网运行与管理

汶川地震发生后,天津市地震局迅速进入应急体制,高效应对突发事件.监测中心、预报中心全体人员坚守岗位,履行职责,较好地完成了汶川地震期间天津地震前兆台网运行监控、数据管理、台站综合评比、数据服务、总结评估等项工作,以无私奉献的团队精神为地震监测预报工作做出了应有的贡献.     

西部管道工程HSE一体化绩效管理应用研究

分析了我国管道工程项目HSE绩效管理存在问题,运用绩效管理理论,结合“PMT（业主）＋PMC（监理）＋EPC（施工总承包方）”一体化模式及西部管道工程,阐述了HSE一体化绩效管理体系的建立及应用情况。