中水回用中平板膜的污染机理分析

采用间歇式生物反应器,对模拟小区生活污水的人工配水进行了生物处理;然后,在操作压力为0.1 MPa,搅拌速度为300 r/min条件下,选用膜生物反应器中常用的聚醚砜(PES,切割分子量分别为2万、1万和5千)、聚丙烯腈(PAN,切割分子量为20万)、聚偏氟乙烯(PVDF,切割分子量为20万)超滤平板膜和聚醚砜(PES,孔径为0.1μm)、聚丙烯腈(PAN,孔径为0.1μm)、聚偏氟乙烯(PVDF,孔径为0.1μm)微滤平板膜在实验室用死端超滤器上分别对活性污泥悬浮液进行了过滤并探讨了和间歇式生物反应器组合在一起用于中水回用的效果,结果表明:每种组合处理后的出水水质为COD＜50 mg/L,NH3-N＜10 mg/L,SS为0 mg/L,浊度为0 NTU,都达到了中水回用的水质标准(CJ25.1-89),其中生物反应器分别与PES超滤膜(5千、1万、2万)和PAN(20万、0.1μm)膜组合时,对COD的去除率较高,但所有组合对NH3-N、TOC去除率及膜的渗透通量都相差不大.此外,根据恒压堵塞过滤定律对膜的污染机理进行的研究证实:对于微滤膜和PAN(20万)超滤膜而言,由滤饼过滤过渡到完全(标准)堵塞,再到滤饼过滤;但对于PVDF(20万)和PES(2万)超滤膜,则由标准堵塞过渡到完全堵塞,再到滤饼过滤;PES(5千、1万)超滤膜的污染机理相对简单,整个过程以滤饼过滤为主.     

Study of factors affecting on the extraction efficiency of polycyclic aromatic hydrocarbons from soils using open-vessel focused microwave-assisted extraction

As part of an evaluation of focused microwave-assisted extraction (FMAE) using an open-vessel system, the effects of matrix, moisture content, ageing, and solvent have been studied on the extraction efficiency of polycyclic aromatic hydrocarbons (PAHs) from spiked soils. PAHs were spiked onto three different uncontaminated air dried and originally wet soil matrices with 1- and 20-day ageing periods. Solvents used were hexane–acetone (1:1), cyclohexane–acetone (1:1) and dichloromethane. FMAE only required a small amount of solvent (20 ml) and short extraction time (10 min) in the open cell under 90 W of microwave power. The results revealed that the extraction efficiency strongly depends on the nature of soil matrix; moisture content may enhance the recoveries of PAHs for many cases; and, the influence of the type of solvent is not significant. A comparison between microwave extraction and 16-h Soxhlet extraction has been made on spiked soils. It evidenced that the microwave method under ambient pressure is a suitable alternative to Soxhlet method for the analysis of PAHs in soils. For the evaluation of the developed FMAE method, three reference materials were used. The PAHs recovered from three reference materials were in a good agreement with reference values.     

Optimal Control Models and Elicitation of Attitudes towards Climate Damages

This paper examines the consequences of various attitudes towards climate damages through a family of stochastic optimal control models (RESPONSE): cost-efficiency for a given temperature ceiling; cost-benefit analysis with a pure preference for current climate regime and full cost-benefit analysis. The choice of a given proxy of climate change risks is actually more than a technical option. It is essentially motivated by the degree of distrust regarding the legitimacy of an assessment of climate damages and the possibility of providing in due time reliable and non controversial estimates. Our results demonstrate that (a) for early decades abatement, the difference between various decision-making frameworks appears to matter less than the difference between stochastic and non stochastic approach given the cascade of uncertainty from emissions to damages; (b) in a stochastic approach, the possibility of non-catastrophic singularities in the damage function is sufficient to significantly increase earlier optimal abatements; (c) a window of opportunity for action exists up to 2040: abatements further delayed may induce significant regret in case of bad news about climate response or singularities in damages.     

Assessment of personal integrated exposure to fine particulate matter of urban residents in Hong Kong

Metropolitan residents are concerned about their exposure to airborne pollutants. But establishing these exposures is challenging. A compact personal exposure kit (PEK) was developed to evaluate personal integrated exposure (PIE) from time-resolved data to particulate matter with aerodynamic diameter less than 2.5 μm (PM_2.5) in five microenvironments, including office, home, commuting, other indoor activities (other than home and office), and outdoor activities experienced both on weekdays and weekends. The study was conducted in Hong Kong. The PEK measured PM_2.5, reported location and several other factors, stored collected data, as well as reported the data back to the investigators using global system for mobile communication (GSM) telemetry. Generally, PM_2.5 concentrations in office microenvironment were found to be the smallest (13.0 μg/m³), whereas the largest PM_2.5 concentration microenvironments were experienced during outdoor activities (54.4 μg/m³). Participants spent more than 85% of their time indoors, including in offices, homes, and other public indoor venues. On average, 42% and 81% of the time were spent in homes, which contributed 52% and 79% of PIE (during weekdays and weekends, respectively), suggesting that improvement of air quality in homes may reduce overall exposures and indicating the need for actions to mitigate possible public health burdens in Hong Kong. This study also found that various indoor/outdoor microenvironments experienced by urban office workers cannot be accurately represented by general urban air quality data reported from the regulatory monitoring. Such personalized air quality information, especially while in transit or in offices and homes, may provide improved information on population exposures to air pollution.

Implications: A newly developed personal exposure kit (PEK) was used to monitor PM_2.5 exposure of metropolitan citizens in their daily life. Different microenvironments and time durations caused various personal integrated exposure (PIE). The stationary monitoring method for PIE was also compared and evaluated with PEK. Positive protection actions can be taken after understanding the major contribution to PM_2.5 exposure.     

以Ca（OH）2为pH调节剂的磷酸氢镁吸附法处理氨氮废水的研究

提出了以Ca（OH）2为pH调节剂、磷酸氢镁（MHP）为吸附剂的氨氮废水处理新方法（MHP吸附法）。MHP吸附法的特点是吸附产物磷酸铵镁（MAP）可通过简单的热分解再生MHP,同时回收高浓度氨水。考察了MAP热分解制备MHP的工艺条件;对氯化铵、硫酸铵及碳酸铵3种模拟氨氮废水体系,分别考察了pH值、温度、氨氮初始浓度对MHP吸附容量的影响;考察了MHP的循环使用性能。研究结果表明,MHP对氨氮具有良好的吸附性能,NH4^＋最高达到了约90mg/g。MHP在循环使用中,对低浓度氨氮废水其吸附容量呈下降趋势,但对高浓度氨氮废水具有良好的循环使用性能。     

应用GIS进行城市震害预测的有利性

研究了应用GIS进行城市震害预测,对于解决或者改善其中存在的以下问题的有利性：①缺乏必要的基础数据;②震害的多因素综合效应考虑不够;③生命线震害预测方法还不成熟;④间接损失预测以及指导救灾关注太少．     

苏州高新区静脉产业循环经济发展的对策

以循环经济3R原则的理念,剖析了苏州高新区静脉产业存在的问题。深入分析了苏州高新区静脉产业发展循环经济的对策。为其按循环经济的规律运行作了有益的探索,也为其循环经济的顺利开展提供了科学依据。     

Further predictors of renal dysplasia in fetal obstructive uropathy: Bladder pressure and biochemistry of ‘fresh’ urine

Urine was aspirated on two consecutive days from the dilated bladder of nine fetuses with lower urinary tract obstruction. Gestational age ranged from 17 to 35 weeks. Renal dysplasia was diagnosed histologically in four fetuses, whereas the other five had normal renal histology or only partial dysplasia. Urinary sodium (Na⁺) and osmolality (Osm) decreased significantly in the second urine sample 1 day after bladder emptying (median decrease: Na⁺ = −11.3 per cent; Osm= −13.3 per cent). Although there were no significant differences between fetuses with or without renal dysplasia, normalization of an initially raised urine Na ⁺ concentration occurred at the second sample in a fetus with partially normal renal histology, thus correcting a false-positive diagnosis of dysplasia. Bladder pressure was measured at the time of the first urine sampling in seven fetuses and in a further eight with bladder outlet obstruction undergoing a single urine aspiration at 18–28 weeks. Bladder pressure was increased above the reference range in 8 of 15 fetuses with urinary obstruction, but there was no correlation between pressure and the degree of impairment of renal function. Although no conclusive clinical guidelines can be drawn from this study for the evaluation of fetal renal function, these findings suggest that, in lower urinary tract obstruction, tubular reabsorption is impeded by the standing pressure in the urinary tract and that improvement of renal function may occur following relief of obstruction.     

可见光响应漂浮式微球光催化剂及其光降解模拟海水中苯酚

为了将光催化技术应用于有机物污染海水的治理,本文首先利用水热还原得到了具有可见光响应的还原商用P25光催化剂,而后将还原后的P25作为活性组分负载在透明的有机玻璃空心微球表面,制成漂浮式微球光催化剂.还原后的P25的表征结果表明,水热条件下金属还原作用会将P25中少量Ti~(4+)还原成Ti~(3+),同时催化剂表面还形成了无序化-内部结晶的核壳结构.这两种结构变化都会显著拓展还原P25催化剂的可见光响应.含苯酚模拟污染海水的光降解实验发现,降解低浓度苯酚时,漂浮型微球光催化剂显示了优异的降解效率,降解5 h的去除率达到了95%以上.由于还原P25光催化剂的稳定性并且漂浮式微球光催化剂能简易回收,在多次重复实验中微球光催化剂都可以保持较高的催化活性.     

北京部分地区大气PM10中多环芳烃的季节性变化

采集了北京城乡结合部和郊区 2003 年 4 个季节大气 PM10样品,用超声萃取-GC/MS 技术分析了其多环芳烃的组成.结果表明,17 种母核多环芳烃总量在8.46~296.57ng/m3之间,城乡结合部的浓度是郊区的1.02~1.58倍.PAHs总量的季节性变化与采样时环境温度显示出较好的负相关性,即冬季>秋季>春季>夏季.郊区和城乡结合部冬季 PAHs 总量分别是夏季的 22.25 倍和 34.41 倍,显示了燃煤取暖对北京冬季大气 PAHs 污染的贡献极为显著.运用多种多环芳烃比值综合判断,北京大气 PM10中 PAHs 主要以燃煤和机动车尾气混合来源为主,石油源和木材燃烧源的贡献较小.