新型气体灭火剂七氟丙烷的性能及其应用

介绍七氟丙烷气体灭火剂的基本性质及特点,阐述七氟丙烷气体灭火剂的灭火原理,分析讨论七氟丙烷气体灭火剂的环境效益、安全可靠性、经济适用性,并对其适用条件进行了说明。     

Microbiota associated with the migration and transformation of chlorinated aliphatic hydrocarbons in groundwater

Pollution of groundwater with chlorinated aliphatic hydrocarbons (CAHs) is a serious environmental problem which is threatening human health. Microorganisms are the major participants in degrading these contaminants. Here, groundwater contaminated for a decade with CAHs was investigated. Numerical simulation and field measurements were used to track and forecast the migration and transformation of the pollutants. The diversity, abundance, and possible activity of groundwater microbial communities at CAH-polluted sites were characterized by molecular approaches. The number of microorganisms was between 5.65E+05 and 1.49E+08 16S rRNA gene clone numbers per liter according to quantitative real-time PCR analysis. In 16S rRNA gene clone libraries constructed from samples along the groundwater flow, eight phyla were detected, and Proteobacteria were dominant (72.8 %). The microbial communities varied with the composition and concentration of pollutants. Meanwhile, toluene monooxygenases and methane monooxygenases capable of degradation of PCE and TCE were detected, demonstrating the major mechanism for PCE and TCE degradation and possibility for in situ remediation by addition of oxygen in this study.     

Scenarios simulation on municipal plastic waste generation of different functional areas of Beijing

With the rapid economic development of China and the improvement of people’s living standards, municipal plastic waste (MPW) has increasingly become a major problem for cities in China. The generation of plastic waste is a system which integrates social, economical and environment factors. There is a certain guiding significance for the determination of urban plastic waste management priorities to research MPW generation with the background of the regional development of the city. As the capital of China, Beijing develops with a typically regional characteristic. This article establishes a generation system model for MPW by the method of system dynamics, and takes Beijing as an example to simulate and forecast the MPW generations of four functional areas on scenarios. The data used in the model were mainly obtained from statistical materials and on-site survey. The results showed a better regulating effect of the generation of MPW of Beijing under an integrated control scenario. In terms of space, MPW generation of the urban function extended districts generated the largest amount of plastic waste, with the largest growth rate; the proportion of MPW generation of the new districts of urban development increased significantly. In terms of generation source, the resident communities source generated the largest amount of the MPW. Based on the results, some suggestions on MPW management are put forward.     

Impact of total organic carbon and chlorine to ammonia ratio on nitrification in a bench-scale drinking water distribution system

Nitrification occurs in chloraminated drinking water systems and is affected by water quality parameters. The aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nitrification potential in a simulated drinking water distribution system as during chloramination. The occurrence of nitrification and activity of nitrifying bacteria was primarily monitored using four rotating annular bioreactors (RAB) with different chlorine to ammonia ratios and total organic carbon (TOC) levels. The results indicated that nitrification occurred despite at a low influent concentration of ammonia, and a high concentration of nitrite nitrogen was detected in the effluent. The study illustrated that reactors 1(R1) and 3 (R3), with higher TOC levels, produced more nitrite nitrogen, which was consistent with the ammonia-oxidizing bacteria (AOB) counts, and was linked to a relatively more rapid decay of chloramines in comparison to their counterparts (R2 and R4). The AOB and HPC counts were correlated during the biofilm formation with the establishment of nitrification. Biofilm AOB abundance was also higher in the high TOC reactors compared with the low TOC reactors. The chlorine to ammonia ratio did not have a significant impact on the occurrence of nitrification. Bulk water with a high TOC level supported the occurrence of nitrification, and AOB development occurred at all examined chlorine to ammonia dose ratios (3:1 or 5:1).     

中国人居环境研究现状中存在的问题

随着经济的发展,人们面临着越来越严重的环境问题,人居环境开始被广泛关注。作者在阅读了近现代中国学者对人居环境研究的80余篇权威期刊文献后,总结了中国人居环境的研究现状,发现研究结论中存在的矛盾并尝试对其进行了理论分析,提出人居环境的发展阶段可划分为三个阶段:人居硬环境时代——人居软环境时代——和谐人居时代,总结出现代中国正处于人居软环境时代,明确人居环境发展的最终理想目标:和谐人居。     

纳米复合材料去除水中苯酚的实验研究

本文对X型纳米分子筛与硅藻土组成的复合材料对废水中苯酚的去除进行了探讨。采用了静态方法进行正交实验,探讨了硅藻土的类型(包括CD02,CD06,CD010和吉林硅藻土JL),硅藻土的用量、X型纳米分子筛的用量、苯酚浓度、搅拌时间及pH值对苯酚去除率的影响。通过各因素对苯酚去除率影响的实验,得出复合材料去除苯酚的最佳实验条件。然后,对复合材料和活性炭分别进行再生实验,确定最佳活化温度,并对再生后的结果进行对比。     

关于鄂尔多斯市东胜区环境噪声功能区的划分及思考

城市区域声环境噪声功能区的划分,是城市各类噪声监测和环境管理的重要依据,也是评价一个城市声环境质量的重要依据。以城市规划为指导,按区域规划用地的主导功能确定,本文对鄂尔多斯市建城区功能区划分过程中所涉及的一些问题及功能区划分后对今后管理所起的作用等问题进行了探讨。     

安宁河东岸西昌段蛇尾巴村滑坡、泥石流成因分析

本文以安宁河东岸西昌段蛇尾巴村滑坡、泥石流为研究对象,针对研究区的情况,选取了坡度、地貌、地质构造、地层岩性、活动构造、地震作用等相关因素,分析了研究区滑坡泥石流的成因,揭示了研究区地质灾害的主要成因为活动构造和坡度。     

一株高浸磷嗜酸氧化硫硫杆菌的分离与鉴定

从矿山土样中分离到一株嗜酸的浸磷矿细菌HY-01,观察其形态并研究其培养特征.结果显示,该菌株为革兰氏阴性、短杆状运动细菌,菌体长1～2μm,宽0.5～0.7 μm,能在pH 1.5～8.0的范围内生长,最适生长温度为37℃,最适pH为1.5～3.0.该菌株可以KNO3、NH4NO3、(NH4)2CO3、NH4H2PO...     

Optimizing water quality monitoring networks using continuous longitudinal monitoring data: a case study of Wen-Rui Tang River, Wenzhou, China

Identification of representative sampling sites is a critical issue in establishing an effective water quality monitoring program. This is especially important at the urban-agriculture interface where water quality conditions can change rapidly over short distances. The objective of this research was to optimize the spatial allocation of discrete monitoring sites for synoptic water quality monitoring through analysis of continuous longitudinal monitoring data collected by attaching a water quality sonde and GPS to a boat. Sampling was conducted six times from March to October 2009 along a 6.5 km segment of the Wen-Rui Tang River in eastern China that represented an urban-agricultural interface. When travelling at a velocity of ～2.4 km h(-1), this resulted in water quality measurements at ～20 m interval. Ammonia nitrogen (NH(4)(+)-N), electrical conductivity (EC), dissolved oxygen (DO), and turbidity data were collected and analyzed using Cluster Analysis (CA) to identify optimal locations for establishment of long-term monitoring sites. The analysis identified two distinct water quality segments for NH(4)(+)-N and EC and three distinct segments for DO and turbidity. According to our research results, the current fixed-location sampling sites should be adjusted to more effectively capture the distinct differences in the spatial distribution of water quality conditions. In addition, this methodology identified river reaches that require more comprehensive study of the factors leading to the changes in water quality within the identified river segment. The study demonstrates that continuous longitudinal monitoring can be a highly effective method for optimizing monitoring site locations for water quality studies.