膜生物反应器在废水处理中的研究现状

膜生物反应器(MBR)是将生物处理技术和膜分离技术相结合的一种新型水处理技术。膜生物反应器具有常规废水处理工艺无法比拟的优势,本文介绍了膜生物反应器的分类、最新组合工艺及其在废水处理中的应用,并详细介绍了膜生物反应器存在的问题以及发展的前景。     

TiO2纳米粒子气-固复相光催化氧化VOCs作用的研究进展

本文总结了90年代以来TiO2纳米粒子气-固复相光催化氧化气相有机污染物的影响因素、反应机理和动力学,阐述了几种特定有机污染物的光催化氧化过程,并对应用前景作出展望.     

E. coli and bacteriophage MS2 disinfection by UV,ozone and the combined UV and ozone processes

The combination of low-dose ozone with ultraviolet （UV） irradiation should be an option to give benefit to disinfection and reduce drawbacks of UV and ozone disinfection. However, less is known about the disinfection performance of UV and ozone （UV/ozone） coexposure and sequential UV-followed-by-ozone （UV- ozone） and ozone-followed-by-UV （ozone-UV） expo- sures. In this study, inactivation of E. coli and bacterioph- age MS2 by UV, ozone, UV/ozone coexposure, and sequential UV-ozone and ozone-UV exposures was investigated and compared. Synergistic effects of 0.5-0.9 log kill on E. coli inactivation, including increases in the rate and efficiency, were observed after the UV/ozone coexposure at ozone concentrations as low as 0.05 mg-L-1 in ultrapure water. The coexposure with 0.02-mg.L-1 ozone did not enhance the inactivation but repressed E. coli photoreactivation. Little enhancement on E. coli inactivation was found after the sequential UV-ozone or ozone-UV exposures. The synergistic effect on MS2 inactivation was less significant after the UV/ozone coexposure, and more significant after the sequential ozone-UV and UV-ozone exposures, which was 0.2 log kill for the former and 0.8 log kill for the latter two processes, at ozone dose of 0.1 mg. t-1 and UV dose of 8.55 mJ. cm 2 in ultrapure water. The synergistic effects on disinfection were also observed in tap water. These results show that the combination of UV and low-dose ozone is a promising technology for securing microbiological quality of water.     

Levels and profiles of Dechlorane Plus in a major E-waste dismantling area in China

Dechlorane Plus (DP) is a high-production volume, chlorinated flame retardant comprising two major isomers, syn- and anti-DP. In this study, levels of DP were measured in soil and earthworm samples in farmland from a typical E-waste dismantling area in China. The concentrations of total DP ranged from 0.17 to 1,990 ng g^?1 dw in soil samples and 3.43 to 89.2 ng g^?1 lw in earthworm samples. Higher DP levels were found in some main E-waste dismantling sites than those in other sites. The ratios of anti-DP to total DP (f _anti) ranged from 0.57 to 0.80 in soil samples and 0.47 to 0.81 in earthworm samples, respectively. The f _anti in most samples in this study was in the range of the reported technical DP values. These results showed that improper E-waste dismantling activities could result in the emission of DP. Most earthworm samples showed very low BSAFs (biota-to-soil accumulation factors) for total DP. The values of BSAF were in the range of 0.0007–1.85, with an average value of 0.23. This study presents the first report of the DP in earthworms, which would be useful for ecological risk assessment of DP in terrestrial ecosystem.     

Suspended solid abatement in a conical fluidized bed flocculator

With the random movement of silica gel beads in a conical fluidized bed, micro-vortices resulting from the fluidization promoted the collision and aggregation of suspended fine kaolin powders. The abatement efficiencies of the suspended fine solids under several hydrodynamic conditions were studied, and a suitable control strategy for operating the conical fluidized bed flocculators was identified. The suspended solids abatement efficiency was found to increase with increasing Camp Number and flocculation time (T), but decreased with the increase of velocity gradient (G) within the range studied in this research (165.1–189.6 s^-1). The abatement efficiencies were all more than 60% at the range of G = 165–180 s^-1 and T = 15–33 s at an initial kaolin solid concentration of 150 mg·L^-1, polymer aluminum chloride dosage of 60 mg·L^-1 and sedimentation time of 20 min. However, the formation of flocs was influenced by the liquid backmixing. Excessive backmixing caused the breakup of flocs and resulted in difficulty for the fine powders to aggregate and sediment to the reactor bottom. The results of the calculated fractal dimension and measured free sedimentation velocity of flocs obtained at different runs showed similar flocs properties, and indicated an easy control strategy for sedimentation of the flocs.     

灾害脆弱性概念模型综述

分析灾害系统脆弱性类型、成因、驱动力及其驱动过程,评价灾害系统脆弱性程度,可为防灾减灾的适应能力和恢复能力建设提供基础信息。对脆弱性的概念、框架和评估原理进行综述,旨在借鉴其思路和方法,改进减灾实践。     

焊接防护具抗热穿透性能测试仪的研制

焊接防护具是指一种保护佩戴者免受由焊接或相关作业所产生的有害光辐射及其他特定有害因素的装置。它是从事焊接与热切割作业人员必备的个体防护装备。抗热穿透性能是表征焊接防护具产品质量和安全性能的最重要技术指标之一。然而,如何快速、便捷、节能、准确地对焊接防护具抗热穿透性能进行检测,是迫切需要解决的技术难题。本文在简要分析国内外眼面部防护标准中抗热穿透性能技术要求和测试方法的基础上,提出了一种测试焊接防护具抗热穿透性能的方法,并成功研制了焊接防护具抗热穿透性能测试仪。     

110mAg root and foliar uptake in vegetables and its migration in soil

110mAg, as a radionuclide of corrosion products in water-cooled nuclear reactors, was detected in the liquid effluents of Guangdong Daya Bay Nuclear Power Station (GNPS) of Daya Bay under normal operation conditions. Experiments on a simulated terrestrial agricultural ecosystem were carried out using the pot experiment approach. The most common plants in Hong Kong and the South China vegetable gardens such as lettuce, Chinese spinach, kale, carrot, pepper, eggplant, bean, flowering cabbage, celery, European onion and cucumber were selected for (110m)Ag root and foliar uptake tests. The results show that carrot, kale and flowering cabbage have the greatest values of soil to plant transfer factor among the vegetables, while(110m)Ag can be transferred to Chinese spinach via foliar uptake. Flowering cabbage, the most popular leafy vegetable locally, could be used as a biomonitor for the radioisotope contamination in vegetables. Soil column and adsorption tests were also carried out to study the leaching ability and distribution coefficient (K(d)) of (110m)Ag in the soil. The results show that most of the radionuclide was adsorbed in the top 1 cm of soil regardless of the pH value. The K(d) was also determined.     

河北省地质地貌灾害与防灾减灾

河北省是我国地质地貌灾害最为严重的地区之一．本文从人类生态学角度,研究地质地貌灾害的成因与分布,并强调通过调整人类活动,减轻灾害损失和影响．     

小麦秸秆生物炭对水中对羟基苯甲酸乙酯的吸附特性

对羟基苯甲酸乙酯属于尼泊金酯类物质,是一种典型的新兴环境污染物.本研究通过制得不同热解温度(300、500和700℃)下的小麦秸秆生物炭(分别表示为BC300、BC500、BC700),对水中对羟基苯甲酸乙酯进行间歇吸附.结果表明,热解温度升高会导致生物炭表面疏水性增强,且引起零电荷点从8.37升至9.42.溶液初始p H值由8升至12时,对羟基苯甲酸乙酯去除率显著递减;此外,溶液离子强度的增强会导致对羟基苯甲酸乙酯去除率的下降.生物炭吸附水中对羟基苯甲酸乙酯的等温吸附过程符合Langmuir方程,其中,最大吸附容量排序为:BC700BC500BC300.同时,吸附过程符合准二级动力学方程,且为吸热自发过程.此外,经过4轮再生吸附,生物炭吸附容量仍可达到最初的90%,其中,BC700展示出最高的吸附效率(92.76%).