Formation of persistent chlorinated aromatic compounds in simulated and real fly ash from iron ore sintering

Effects of carbon concentration and Cu additive in simulated fly ash (SFA) and real fly ash (RFA) on the formation of polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxins (PCDDs), chlorobenzenes, and polychlorinated biphenyls which were all regarded as persistent chlorinated aromatics in iron ore sintering were investigated. In the annealing process of SFA with various carbon contents, the yield of chlorinated aromatics and the I-TEQ obtained their maximum at 10 wt% carbon content. Active carbon in SFA acted as the carbon source as well as an adsorbent which led to higher production of PCDD/F in solid phase at 10 wt% carbon content. The increase of carbon content will be beneficial on the formation of 2,3,7,8-Chloro-substituted PCDF compared with 2,3,7,8-Chloro-substituted PCDD. In addition, the CuCl₂·2H₂O was a much more powerful catalyst in the formation of chlorinated aromatic compounds compared with elementary Cu, since it served as both a catalyst and a chlorine donor. However, the RFA behaved similarly with SFA with elementary Cu in the formation of chlorinated aromatic compounds. The effect of carbon content and copper additives on formation of 2,3,7,8-chloro-substituted congeners displayed similar characteristics with the tetra- to octa-PCDD/F isomers and even the total PCDD/Fs.     

Measurement of the vertical profile of atmospheric SO2 during the heating period in Beijing on days of high air pollution

This paper reports altitude-resolved concentrations of sulfur dioxide (SO₂) and particulate matter up to 10 microns in diameter (PM₁₀) in the planetary boundary layer of major urban centers during extreme pollution episodes. The concentration of SO₂ was observed continuously from November 24, 2004, to December 4, 2004, in Beijing during the heating period. Fluorescence SO₂ analyzers were used to measure the atmospheric SO₂ concentrations. Four SO₂ analyzers were placed at 4 different levels (8 m, 47 m, 120 m, and 280 m) of the 325-m high meteorological observation tower of the Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences. A maximal SO₂ concentration of 172.3 ppb was measured during this pollution episode, and SO₂ concentration increased with altitude and reached its maximal value at ～50 m. The study also analyzed the meteorological situation before, during, and after the pollution episode.     

磁强化臭氧氧化生化处理二级出水的试验研究

在外加磁场作用下,采用臭氧氧化对青岛某污水处理厂生化处理二级出水进行了处理.考察了臭氧投加量、反应时间、磁场强度对处理效果的影响.经过多次试验得到的最佳运行参数为:臭氧投加量3.5 mg/L;反应时间10 min;磁场强度3 000Gs.外加磁场提高了臭氧氧化的效率,缩短了反应时间.     

无银催化-分光光度法测定COD的研究

以XS-LP为催化剂,探讨了改进的无银催化HACH法测定污水中COD的系列条件实验。结果表明:在药剂A,B的投配比为1∶2,投加总量为12 g/L的条件下,其准确度、精密度与国标法有较好的可比性,分别小于10%和3%;对实际废水的测量结果与国标回流法的相关系数分别高达0.9951和0.9874,可满足一般环境检测技术规范要求。     

DGGE、T-RFLP 、LH-PCR对两种活性污泥的微生物种群多样性分析的比较

采用基于PCR扩增的分子生态技术DGGE、T-RFLP和LH-PCR,对2种典型污水处理系统中的活性污泥（生活污泥、焦化污泥）进行微生物种群多样性分析;并以此比较3种技术的优劣,提出不同应用条件下研究方法的选择依据。根据实验结果：DGGE得到的条带较多,但误差来源也最多;T-RFLP技术较为灵敏,但需要选择适当的内切酶,严格控制酶切条件,并且文库比对误差较大;而LH-PCR操作简单,结果稳定性较高。虽然目前尚无法判断3种方法的准确性,但LH-PCR在活性污泥的微生物种群多样性分析中已显示出潜在优势。     

表面活性剂清洗处理重度石油污染土壤

为了优化表面活性剂清洗处理重度石油污染土壤的方法和具体洗脱条件参数,采集山东省东营市胜利油田污染土壤,研究了阴离子-非离子混合表面活性剂对该土壤中石油类污染物的去除效果。应用化学热洗原理,主要考查了表面活性剂配比、投加量、清洗温度及清洗助剂对去除效果的影响。实验得到的清洗处理最佳条件为：使用LAS与TX-100质量比为8∶2的组合表面活性剂,总表面活性剂浓度为3 g/L,助剂硅酸钠浓度为5 g/L,75℃条件下搅拌1 h。清洗后土壤含油量从20%下降到4.6%,去除率达到76.9%。废水回用实验表明,清洗处理的废水对土壤中石油烃类物质仍有一定的去除效果。废水回用比从30%到100%时,对土壤中石油烃的去除率都可达到55%以上。对废水进行二次回用时仍能去除18.8%的污染物。     

渗滤液污染包气带中铁的形态变化

从渗滤液场龄和包气带岩性两方面出发,研究了新、老渗滤液对亚粘土和细砂包气带环境中Fe的含量及存在形态的影响。结果表明：新、老渗滤液分别能使细砂包气带介质中除残渣态以外Fe的含量增加16.68%或降低13.82%。亚粘土比细砂作为包气带介质更能缓冲渗滤液对介质中Fe的影响程度,其受影响范围在包气带0～20 cm深度处。当亚粘土为介质的包气带被新渗滤液污染后,其表层介质中碳酸盐结合态Fe的含量会增加15倍之多,为缓冲渗滤液Fe的污染做出了巨大贡献,但这部分Fe的存在也是潜在的二次污染源,在环境pH急剧变化的情况下,它可能会引起地下水高铁污染。     

China-Indian Silk Trade： Current Production and Future Prospects

As an important traditional labor-intensive industry of both India and China, the cocoon silk industry has long made great contributions to the ecological environment protection, rural economic development and the increase in export income of both countries. India is not only a very important cocoon silk trading partner, but an important production competitor of China. In recent years, there has been a large increase in the production and trade of the cocoon silk between China and India; however, China relies heavily on Indian market, which leads to a tendency of further deterioration in the silk trade environment between both countries. The present article makes an empirical study of the cocoon silk resources of the two countries and the scale, product mix and market structure of China-Indian silk trade from 2001 to 2007. Overall silk trading volumes from China to India and market concentration rate are on the increase because of the superiority of Chinese cocoon silk production over that of India. Owing to scattered market share and export that mainly focused on raw materials product, there has been a phenomenon of price reduction and quantity increase. India carries out fierce competition with China in the international market and even imposes antidumping sanction on Chinese silk, which are key factors restricting further increase between China-India trade. Based on the abovementioned facts, the authors aim to put forward suggestions for steadily developing the production and trade of China＇s silk.     

Influence of titanium dioxide nanoparticles on speciation and bioavailability of arsenite

In this study, the influence of the co-existence of TiO₂ nanoparticles on the speciation of arsenite [As(III)] was studied by observing its adsorption and valence changing. Moreover, the influence of TiO₂ nanoparticles on the bioavailability of As(III) was examined by bioaccumulation test using carp (Cyprinus carpio). The results showed that TiO₂ nanoparticles have a significant adsorption capacity for As (III). Equilibrium was established within 30 min, with about 30% of the initial As (III) being adsorbed onto TiO₂ nanoparticles. Most of aqueous As (III) was oxidized to As(V) in the presence of TiO₂ nanoparticles under sunlight. The carp accumulated considerably more As in the presence of TiO₂ nanoparticles than in the absence of TiO₂ nanoparticles, and after 25-day exposure, As concentration in carp increased by 44%. Accumulation of As in viscera, gills and muscle of the carp was significantly enhanced by the presence of TiO₂ nanoparticles.     

紫外线消毒技术用于污水处理的现状与发展前景

污水处理中紫外消毒方法与传统消毒方法相比之下具有不需要投加化学药剂、不产生有毒有害副产物、消毒效率高、操作简单、便于运行管理等特点。本文着重介绍了目前用于消毒的紫外灯的种类,并阐述了浊度、微生物种类、光复活性能等影响紫外消毒效果的因素,最后对未来紫外消毒方法发展的前景做出了分析。