突发性环境污染事故应急预警系统发展探讨

在介绍突发性环境污染事故的概念、类型与特性的基础上,综述了近年来国内外对这一领域的研究进展．并结合“5S”技术提出突发性环境污染事故应急预警系统的全程模拟。     

污染底泥及其间隙水分层特性的模拟实验研究

底泥冲刷沉降、再悬浮是作用于水环境内源污染的主要因素,而底泥间隙水的污染释放则是主要途径。通过底泥培养实验,研究了污染底泥及其间隙水的分层特性。结果表明,底泥及其污染物具有显著的分层特性。底泥间隙水中CODMn随深度的增加略有下降的趋势;底泥湿容重和干容重呈增大的趋势;含水率随底泥深度的增加而减小。底泥深度对底泥泥沙颗粒的级配有很大影响,在表层以细颗粒为主,随着深度的增加．底泥粒径增加,但趋势衰减较快。这对底泥冲刷作用下的再悬浮有很大影响。     

印染废水生物强化处理技术研究进展

印染废水是国内外公认的难处理的工业废水之一 ,活性污泥法是目前最常用的处理方法 ,但还存在诸多问题。在分析中 ,主要从生物强化技术、固定化微生物技术和微生物活性增加技术等方面 ,总结了废水生物处理技术强化研究进展 ,并讨论了今后的研究方向。     

Progress in developing an ANN model for air pollution index forecast

An air pollution index (API) reporting system is introduced to selected cities of China for public communication on air quality data. Shanghai is the first city in China providing daily average API reports and forecasts. This paper describes the development of an artificial neural network (ANN) model for the API forecasting in Shanghai. It is a multiple layer perceptron (MLP) network, with meteorological forecasting data as the main input, to output the next day average API values. However, the initial version of the MLP model did not work well. To improve the model, a series of tests were conducted with respect to the training method and structure optimization. Based on the test results, the training algorithm was modified and a new model was built. The new model is now being used in Shanghai for API forecasting. Its performance is shown reasonably well in comparison with observation. The application of the old model was only weakly correlated with observation. In 1-year application, the correlation coefficients were 0.2314, 0.1022 and 0.1710 for TSP, SO₂ and NO_x, respectively. But for the new model, for over 8 months application, the correlation coefficients are raised to 0.6056, 0.6993 and 0.6300 for PM₁₀, SO₂, and NO₂. Further, the new algorithm does not rely on manpower intervention so that it is now being applied in several other Chinese cities with quite different meteorological conditions. The structure of the model and the application results are presented in this paper and also the problems to be further studied.     

采用TSF技术改善电力变压器运行的安全性

分析了无功功率和高次谐波对电力变压器的危害,介绍了晶闸管投切滤波器(TSF)装置的特点、结构原理．提出了TSF装置在工厂实际应用中的主电路结构,操作及控制方案。实践证明,TSF晶闸管投切滤波器装置起到了高效节能、优化电能质量的作用,保证了电网的安全运行。     

基于三角随机模拟和ArcGIS的河流水环境健康风险评价模型

基于河流水环境系统中随机性、模糊性等多种不确定性共存或交叉存在的特性,将三角模糊数与随机模拟方法相耦合,构建了三角随机模拟模型,并将其应用到湘江(长沙段)的健康风险评价中。通过将各参数浓度进行三角模糊化和随机模拟,结果表明,各断面污染物造成的健康风险的变化趋势,总体沿湘江上游至下游逐步降低,表现为昭山 > 猴子石 > 五一桥 > 橘子洲 > 乔口 > 三汊矶,且昭山、三汊矶断面和乔口断面均有恶化趋势。相对于常规的确定性方法,本模型能够得出评价区域健康风险的可能值区间及其相应的概率水平等定量信息,更加客观、全面地表征评价区域的风险状态及其空间分布差异,为决策者提供更多有用的信息。     

Research and application of method of oxygen isotope of inorganic phosphate in Beijing agricultural soils

Phosphorus (P) in agricultural ecosystems is an essential and limited element for plants and microorganisms. However, environmental problems caused by P accumulation as well as by P loss have become more and more serious. Oxygen isotopes of phosphate can trace the sources, migration, and transformation of P in agricultural soils. In order to use the isotopes of phosphate oxygen, appropriate extraction and purification methods for inorganic phosphate from soils are necessary. Here, we combined two different methods to analyze the oxygen isotopic composition of inorganic phosphate (δ¹⁸O_P) from chemical fertilizers and different fractions (Milli-Q water, 0.5 mol L^?1 NaHCO₃ (pH = 8.5), 0.1 mol L^?1 NaOH and 1 mol L^?1 HCl) of agricultural soils from the Beijing area. The δ¹⁸O_P results of the water extracts and NaHCO₃ extracts in most samples were close to the calculated equilibrium value. These phenomena can be explained by rapid P cycling in soils and the influence of chemical fertilizers. The δ¹⁸O_P value of the water extracts and NaHCO₃ extracts in some soil samples below the equilibrium value may be caused by the hydrolysis of organic P fractions mediated by extracellular enzymes. The δ¹⁸O_P values of the NaOH extracts were above the calculated equilibrium value reflecting the balance state between microbial uptake of phosphate and the release of intracellular phosphate back to the soil. The HCl extracts with the lowest δ¹⁸O_P values and highest phosphate concentrations indicated that the HCl fraction was affected by microbial activity. Hence, these δ¹⁸O_p values likely reflected the oxygen isotopic values of the parent materials. The results suggested that phosphate oxygen isotope analyses could be an effective tool in order to trace phosphate sources, transformation processes, and its utilization by microorganisms in agricultural soils.     

紫外-Fenton法处理高盐有机废水

以某电镀厂水回用系统产生的高盐有机废水为对象,对比研究了Fenton、UV-Fenton等工艺去除COD性能,考察了初始pH、H2O2投加量、Fe2+与H2O2摩尔比、反应时间等参数对处理效果的影响。结果表明:UV-Fenton工艺的最佳条件为初始pH=3.0,H2O2的投加量3 mmol/L,RFe2+:H2O2=1:1,反应时间30 min;在此条件下,COD去除率可达到60%以上,分别较Fenton和UV-H2O2工艺提高23.0%和39.3%。UV-Fenton工艺中,Fenton与UV表现出良好的协同效果,其处理效果较单独Fenton和单独UV处理效果之和高14.7%。UV的引入促进Fe(II)/Fe(Ⅲ)循环,可以提高·OH生成量以及Fe2+与H2O2利用率。UV-Fenton是处理高盐有机废水的可行工艺之一。     

电絮凝-超滤除氟工艺参数优化研究

电絮凝-超滤(electrocoagulation-ultrafiltration,EC-UF)工艺在饮用水除氟方面具有良好的应用前景。研究了EC-UF除氟效果和膜污染过程,考察了电流密度、水力停留时间、初始pH、初始氟浓度对除氟效果和膜污染的影响。结果表明,在连续流下EC-UF工艺除氟效果良好,在电流密度30 A/m2、水力停留时间20 min、初始pH在6.0~7.0的最佳工艺条件下,氟的去除率达到80%以上。膜污染主要是由电解过程产生的铝絮凝剂与氟离子形成的颗粒物质导致。上述结果为EC-UF除氟工艺改进提供了参考和依据。     

臭氧对再生水中指示病原微生物的灭活特性

以臭氧投加量(TOD)为臭氧消耗剂量评价指标,研究了北京市某实际再生水中臭氧对大肠杆菌及枯草芽孢的灭活特性,以及消毒过程中臭氧对溶解性有机碳(DOC)、色度、UV254、荧光强度的去除效果。在此基础之上,分析了色度与指示病原微生物灭活特性之间的相关性。结果表明,臭氧对大肠杆菌及枯草芽孢的灭活特性与余臭氧浓度有关。当水中无法检测到余臭氧时,随着TOD的增加,大肠杆菌灭活率增加的速率较慢,TOD增加 3 mg/L,灭活率增加了1.5 log。枯草芽孢则无显著灭活。当水中余臭氧浓度大于0时,大肠杆菌灭活率增加的速率快速提升,TOD增加 3 mg/L,灭活率增加了3 log。枯草芽孢灭活率也随TOD的增加而显著增加。消毒过程中,DOC无显著变化,而臭氧对色度、UV254、三维荧光强度的去除效果显著。当色度随TOD的增加而趋于稳定时,水中余臭氧浓度开始显著上升,预示着指示病原微生物开始进入高效灭活阶段。同时,进水色度越大,指示病原微生物进入高效灭活阶段所需的TOD越大。