水源水中摇蚊幼虫的孳生与生态控制

摇蚊幼虫(红虫)在城市供水系统中的出现,成为困扰水厂正常生产运行的又一水处理难题.首先对其生理特性与环境因子之间的关系进行了论述,然后从生态学角度出发,利用生态群落中的食物链关系,分析了富营养化水体中摇蚊幼虫大量孳生的原因.在此基础上提出了利用合理的生物操纵技术,通过鱼类与水生生物间的"下行效应",以达到恢复生态平衡并控制摇蚊幼虫孳生为目的的生态治理方案.     

浸渍改性活性碳纤维吸附氮氧化物性能

为实现新风在通过空调进入室内前已被优化的目的, 搭建了一套开式循环系统。通过对活性碳纤维进行浸渍改性, 采用比表面测定、SEM观察、XPS分析、傅里叶变换红外谱图分析对改性前后活性碳纤维进行了表征; 定量研究了室外氮氧化物初始浓度、温度和风速等环境因素对改性前后活性碳纤维吸附氮氧化物效率的影响。结果表明, 改性对活性碳纤维表面活性官能团种类、含氧官能团数量、表面微观结构及比表面积等特性均有显著影响, 提高了其对氮氧化物的吸附效率; 室外初始浓度、风速、温度对改性前后活性碳纤维吸附氮氧化物效率的变化趋势基本一致; 改性前后活性碳纤维对氮氧化物的吸附率随初始浓度的升高而逐渐降低, 随过滤器处风速增大先升高后降低, 随过滤器处温度的升高先升高后降低。改性后活性碳纤维对空气中氮氧化物的吸附率明显提高, 可以将其应用于空调系统中。     

Synergetic effects of anodic-cathodic electrocatalysis for phenol degradation in the presence of iron(II)

A novel electrocatalysis method for phenol degradation was described using a β-PbO₂ anode modified with fluorine resin and a Ni–Cr–Ti alloy cathode. In case of air sparging at the cathodic zone, the techniques of anodic–cathodic electrocatalysis (ACEC) and ferrous ion catalyzed anodic–cathodic electrocatalysis (FACEC) in the presence of iron(II) were developed. Both of ACEC and FACEC were more effective than anodic electrocatalysis (AEC). The percentage of phenol eliminated by FACEC could increase by nearly 30% compared with that of AEC, and the current efficiency could reach to 70%. Important operating factors such as ferrous ion concentration, air-sparging rate and applied current were investigated and it was found that such beneficial effects could be achieved at a suitable current and ratio of the concentration of ferrous ion to the air sparged. The mechanism of phenol degradation is proposed to be the generation of hydroxyl radicals concerned with the two electrodes. Results also indicated that the process provided an efficient way to regenerate ferrous ion compared with the conventional Fenton's system.     

质子化壳聚糖的除磷性能

壳聚糖是一类无毒无害的天然高分子絮凝剂,为了提高壳聚糖在污水处理中的除磷性能,采用硫酸溶液对壳聚糖进行质子化改性;考察了质子化度(硫酸溶液pH值)、吸附时间以及原水pH值对除磷效率的影响。研究结果表明,质子化度越大,总磷去除效率越高;在吸附时间为40～50 min的范围内,总磷去除率最大;原水pH值对质子化壳聚糖的总磷去除效率有明显影响,在质子化度较低时(硫酸溶液pH值≥3),随着原水pH值的增加,总磷去除率降低,在质子化度较高时(硫酸溶液pH值=2),在原水pH=6时,总磷去除率最大;质子化壳聚糖的吸附过程较好地遵循Lagergren准二级动力学模型和Langmuir吸附等温方程,吸附热力学参数ΔH<0,ΔG<0,ΔS<0,吸附过程表现为放热、自发的单分子层化学吸附过程。     

Enhanced experimental flexibility and control in ecotoxicological mesocosm experiments--a new outdoor and indoor pond and stream system

Scope The German Federal Environmental Agency has put into operation a new modular mesocosm system consisting of eight outdoor and eight indoor ponds and streams in order to investigate fate and effects of chemicals and municipal wastewater in aquatic ecosystems. General design and special characteristics are given to demonstrate the wide range of possibilities for experimental research. - General design. Each of the 16 streams with riffle and pool sections can be varied in length up to 106 m. The streams can be run as circular or flow-through systems at a flow velocity of 0.02 to 0.6 m/s. Physico-chemical standard parameters are measured on-line. The 16 ponds, which can be connected to the stream systems, are equipped with drainage and pore water-sampling devices for simulating processes in the littoral zone including influent and effluent ground water flow. Perspectives Since the highly flexible and controllable construction also allows treating a wide range of hydrological and ecological experiments external institutions are invited to submit proposals.     

Endpoint ‘floating leaves’ of <Emphasis Type="Italic">Potamogeton natans</Emphasis>: A new method to evaluate the development of macrophytes in pond mesocosms

Goal, Scope and Background One of the advantages of long-term mesocosm experiments as compared to short-term standard toxicity tests in the laboratory is the potential for detecting secondary effects due to the interaction of species and recovery with biomass of macrophytes being an important endpoint. However, generating biomass data by harvesting is often laborious, time-consuming, costly and restricted to the end of the experiment. Moreover, valuable information may get lost, in particular in single application studies, since maximal primary effects and secondary effects or recovery occur per se at different times. Potamogeton natans was used as an example in order to test whether number and area of floating leaves can be reliably measured and be used as intermediate and final endpoints in mesocosm effect studies. Methods Digital photos, which were taken of the water surface in the course of an indoor pond mesocosm study on herbicide effects, were subjected to image analysis. The results were compared to wet weight and ash-free dry weight of Potamogeton at the end of the herbicide study. Results and Discussion Both number and area of floating leaves indicated the same herbicide effects as wet weight and ash-free dry weight of Potamogeton. Error introduced by the different work steps is small and can be further minimised by a number of method improvements. Recommendations and Perspectives In indoor mesocosm studies, errors due to the perspective adjustment may be circumvented by taking the photos perpendicular to the water surface. Correction for lens aberration, identical light conditions and the use of fluorescence images are considered promising. Field applications are proposed.     

家用洗衣粉中磷对斜生栅藻生长的影响

以洗衣粉中的有机磷为磷源,通过室内模拟的方法研究在不同磷浓度的水体条件下斜生栅藻的生长情况,以及磷对斜生栅藻的生长是否有毒害作用.通过显微计数测定藻细胞数目来探讨洗衣粉中磷对斜生栅藻生长的影响;同时分析了洗衣粉中磷对斜生栅藻96 h生长期中光合色素的影响.结果表明,洗衣粉中的磷除了促进藻生长外,其浓度过低或过高都会抑制藻的生长.由实验结果可得,磷对藻生长的富营养化作用和毒性作用取决于磷浓度的高低.     

黄孢原毛平革菌处理染料废水过程中细胞结构损伤效应研究

利用透射电子显微镜观察分析白腐真菌(黄孢原毛平革菌)在处理染料废水活性艳红X-3B过程中,染料和盐度对黄孢原毛平革菌的细胞结构产生的毒性作用.结果表明:活性艳红X-3B染料对黄孢原毛平革菌产生生物毒性作用,且随着染料浓度的增加,细胞受损伤程度不断加深.加入100 mg/L的染料活性艳红X-3B后,黄孢原毛平革菌菌丝细胞形态发生变化,出现质壁分离现象;染料浓度进一步加大,菌丝细胞超微结构受到损伤逐渐严重.染料废水中的盐度对黄孢原毛平革菌细胞也会造成损伤,且损伤程度随盐度增大而增大.NaCl浓度为3 g/L时,菌丝细胞发生质壁分离;而当NaCl加入量高于8 g/L时,细胞膜受损,线粒体、细胞核呈现空泡化,表现为受到不可逆的损伤.染料和盐双因子对黄孢原毛平革菌细胞的损伤效应表现为其损伤程度与单因子作用一致,且染料的影响作用占主导.     

多米诺效应的风险分析方法

介绍与分析多米诺效应的相关研究,并针对多米诺效应的定量风险分析,建立了从多米诺场景辨识到后果分析的多米诺效应定量分析方法.通过分析初始事故带来的物理效应对邻近设备的影响,计算了二次设备的损坏概率;分析了多米诺场景,计算了多米诺事故频率,并根据多米诺事故的后果得到个人风险和社会风险曲线.多米诺效应的风险是工业区一个潜在的严重风险,加强多米诺效应的研究对工厂和工业区的安全管理与规划都有重要意义.     

Inhibiting effects by Fe2O3 on combustion and explosion characteristics of ABS resin

The global increase in the use of, and reliance on, plastics has prompted the demand for acrylonitrile-butadiene-styrene (ABS) resin in various fields. With this increased requirement, numerous failures have occurred in the ABS process. Those incidents, resulting from electrostatic discharge, powder accumulation, heat accumulation, construction sparks, and plant fires, have caused dust fire and explosions.In this study, the ABS resin was gleaned from the site and tested for its explosion parameters, including minimum ignition temperature of dust cloud (MIT_C), minimum ignition energy (MIE), and minimum explosion concentration (MEC). To improve loss prevention in the manufacturing process, ferric oxide (Fe₂O₃) as an inert additive was added in the ABS powder. According to the MIE test, Fe₂O₃ has an apparent inhibiting effect on dust explosion for the ABS dust. With the proportion of Fe₂O₃ increased from 25 to 50 mass% in ABS, the MIE increased from 67 to 540 mJ. The explosion tests via 20-L apparatus indicated that Fe₂O₃ mixed with ABS could not increase the MEC significantly. However, the explosion pressure dropped by increasing in the ratio of Fe₂O₃ in ABS. This inerting strategy of ABS was deemed to substantially lessen the probability and severity of fire and explosion.