Urban stormwater quality control analysis with detention ponds.

This paper presents methodologies for the development of stormwater quality control measures based on the derived probability distribution approach. These stormwater control measures, such as the fraction of pollutant removed from storage facilities, are closed-form analytical models and can be effectively used to evaluate pollutant loads to receiving waters. In this study, a simple form of rainfall-runoff transformation with lumped parameters is first extended to take into account the spatial variations in model parameters. Second, the infiltration process is further incorporated to the rainfall-runoff transformation. This study demonstrates that analytical models can be developed with various levels of complexity based on different hydrologic considerations. The performance of the analytical models is evaluated in a case study, and the results indicate that, with an appropriately formulated rainfall-runoff transformation, analytical stormwater runoff models are capable of providing comparable results to continuous simulation models in the evaluation of the long-term performance of storage facilities.     

滇池流域某分流制小区雨水径流水质及初期冲刷规律研究

为研究滇池流域呈贡地区典型城市小区的雨水径流水质规律及其初期冲刷效应,以便为揭示滇池污染原因和水环境治理积累基础资料,研究选取洛龙河公园旁边一典型分流制城市小区为对象,在雨水排放口布置监测点进行雨水水质水量监测.结果表明,雨水径流污染较为严重,各场次TSS、COD的EMC值都超过了《城镇污水处理厂污染物排放标准》(GB 18918-2002)的一级B标准.初期冲刷效应普遍存在,且随着雨强的增大而增强,截留降雨前期50%的雨水径流量,能有效截留TSS、COD、TN、TP、NH3-N的比例分别为56.1%~68.3%、55.1%~64.0%、54.9%~61.4%、44.4%~57.7%和54.7%~58.0%.滇池流域呈贡地区城市小区在雨水径流量累积达到0.6之前,截留效率随着截留径流量的比例增加而增加,控制截留的径流量体积比例在0.4~0.8能够取得较高的污染物截留效率.     

建筑屋顶雨水径流初期冲刷效应研究

以无量纲化后的雨水径流污染物和径流输送量为基础,通过引入间隙函数,建立了雨水径流污染物的初期冲刷效应定量评价公式,对建筑屋顶雨水初期冲刷现象进行了研究.结果表明:(1)建筑屋顶雨水径流污染物浓度总体上呈现出前期高于后期的现象,且污染物浓度较低,建筑屋顶雨水利用可作为雨水利用的优先方向.(2)间隙函数存在峰值区域,峰值区...     

Water quality performance of a batch-type stormwater detention basin.

The objective of this research was to modify an extended detention basin to provide batch treatment of stormwater runoff. An automated valve/controller was developed and placed on the outlet of a detention basin in Austin, Texas, which allowed the water quality volume to be retained in the basin for a preset length of time. The influent and effluent of the modified basin were monitored for total suspended solids (TSS), nutrients, chemical oxygen demand (COD), and total and dissolved metals. Statistically significant removal of total metals, COD, total nitrogen, total phosphorus, and TSS was observed, with a discharge event mean TSS concentration of 7 mg/L and a TSS removal efficiency of 91%. The modified basin has substantially better pollutant removal than conventional extended detention basins and is comparable with that of Austin sand filters, which are a common structural stormwater treatment system in the Austin area. The valve also can be used to isolate hazardous material spills.     

生物滞留池改善城市雨水径流水质的研究进展

如何有效控制城市雨水径流所带来的面源污染已成为城市管理工作所面临的重要难题之一.作为城市暴雨最佳管理措施(BMPs)中的技术之一,生物滞留池可有效控制城市面源污染.总结了生物滞留池在改善城市雨水径流水质方面的研究进展,简要分析了生物滞留池去除污染物的机制.研究结果表明,生物滞留池对雨水径流中的总悬浮颗粒物(TSS)、重...     

The influence of production systems on meat quality, with emphasis on pork

Technological, nutritional, and sensory meat quality may be influenced by multiple interacting factors before and after slaughter. Reviewing the literature, it can be seen that alterations aimed at creating more sustainable production systems for pig meat generally have either no effect or a lowering effect on the ultimate pH value of the meat. Some studies indicate reduced water-holding capacity in sustainably produced pork. Outdoor production may be expected to increase further the shear force of the meat compared to conventional systems. The color may be affected in different ways, leading to either darker, more pigmented meat or paler, structurally effected meat. The more unsaturated profile of the lipids in meat produced in a system that includes feeds containing polyunsaturated fatty acids is favorable with respect to the nutritional quality of the meat. To conclude, the combinatory effects of, for example, feeding, production systems, genotype, sex, and preslaughter treatments, have to be addressed.     

Comparison of artificial neural network and regression models in the prediction of urban stormwater quality.

Urban stormwater quality is influenced by many interrelated processes. However, the site-specific nature of these complex processes makes stormwater quality difficult to predict using physically based process models. This has resulted in the need for more empirical techniques. In this study, artificial neural networks (ANN) were used to model urban stormwater quality. A total of 5 different constituents were analyzed-chemical oxygen demand, lead, suspended solids, total Kjeldahl nitrogen, and total phosphorus. Input variables were selected using stepwise linear regression models, calibrated on logarithmically transformed data. Artificial neural networks models were then developed and compared with the regression models. The results from the analyses indicate that multiple linear regression models were more applicable for predicting urban stormwater quality than ANN models.     

A load model based on antecedent dry periods for pollutants in stormwater.

A load model for stormwater constituents is proposed that describes mass retained on the drainage area after previous storms, as a function of a weighted sum of previous antecedent dry periods. It was used to compute the event load for 14 constituents--zinc, copper, cadmium, nickel, chromium, lead, mercury, silver, total suspended solids (TSS), E. coli, fecal coliform, total soluble phosphorus, total phosphorus, and 5-day biochemical oxygen demand. The results show acceptable fits for most constituents based on over 400 rain events (2000 to 2004) in Milwaukee, Wisconsin. Considering the retained pollutant mass after one previous storm rather than assuming the area to be clean after the previous storm gives more accurate results for all constituents, except TSS and silver. The model can be used for mixed land-use areas. The ratios of deposition fluxes of zinc and individual metals were determined at a major parking lot producing a profile characteristic of automobile emissions.     

A decision fusion method based on classification models for water quality monitoring

Environmental Science and Pollution Research - Monitoring of water quality is one of the world’s main intentions for countries. Classification techniques based on support vector machines...     

A framework for error analysis of a long-range transport model with emphasis on parameter uncertainty

A comprehensive framework for model error analysis is applied to the EMEP-W model of longrange transport of sulfur in Europe. This framework includes a proposed taxonomy of model uncertainties. Parameter uncertainties were investigated by Monte Carlo simulation of two source-receptor combinations. A 20% input parameter uncertainty (expressed as a coefficient of variation = standard deviation/mean) yielded a 15–22% output error of total sulfur deposition. The relationship between output error and input uncertainty was approximately proportional. Covariance between parameters can have an important effect on computed model error, and can either exaggerate or reduce errors compared to the uncorrelated case. Of the model state variables, SO₂ air concentration and wet deposition had the highest error, and total sulfur deposition the lowest. It was also found that it is more important to specify the dispersion of the input parameter frequency distributions than their shape. The results of the model error analysis were applied to routine calculations of deposition in Europe. An error (coefficient of variation) of 20% for transfer coefficients throughout Europe yielded spatial variations in the order of a few tens to a few hundreds of km in computed deposition isolines of 2 and 5 g sulfur m⁻²a⁻¹.     

A method to determine the effect of mineral dust aerosols on air quality

Natural mineral dust storms (DS) from the Arabo-African region blow over the Mediterranean, reach Israel, and add to the anthropogenic particulate pollution. The effects of mineral dust on air quality in Israel were investigated using only PM10 and PM2.5 automatic measurements. The method does not require any other inputs such as satellite observations, model back-trajectories, dust forecast models, or mineralogical analyses. The method employs an automatic algorithm with three thresholds: the half-hour PM10 average must be above 100, this level is maintained for at least 3 h, and the maximum concentration recorded is above 180 μg m^?3. The algorithm was designed for Israel, but can be adapted for other locations.The contribution of DS caused PM10 values to exceed the Israeli annual standard of 60 μg m^?3 year^?1 in 6 of the 12 years examined. The DS contribution to PM10 annual average ranged from 9.4% to 29.5%. The level recommended by WHO, 20 μg m^?3 year^?1, was exceeded every year even without the DS contribution. The number of days in which the daily Israeli standard (150 μg m^?3) was exceeded during the 12 years was 6–20 days per year. The number of days in which the daily standard was exceeded shows an increasing trend of 7 days per decade.PM2.5 in Israel is in the range 40–56% of PM10. PM2.5 values were over the recommended standard with and without DS. The contribution of DS to annual average of PM2.5 ranged from 3.6% to 19.1%.The automatic algorithm was calibrated with a list of Dust Storms identified by visual means supported by mineralogical analysis. Mineralogical analyses of single particles were performed using Environmental Scanning Electron Microscope (ESEM). Two representative samples are given. The main difference is that the particles of the Saudi-Arabian storm had much more palygorskite, while the North-African storm had more sea-salt and organic particles. The mineral composition differences indicate that analysis can differentiate between sources.     

基于IGA-BP网络的水质预测方法

针对水质预测中传统BP神经网络模型收敛速度慢,对隐层结点选取缺乏有效的手段等问题,引入了遗传算法优化BP网络的结构和隐层神经元阈值和连接权值,通过设计灵活的实数编码方案和新型交叉算子等,对实数编码遗传算法进行改进,在此基础上,提出了一种基于改进的实数编码遗传算法优化BP神经网络(IGA-BP)的水质预测新模型,并以安徽蚌埠蚌埠闸逐周水质监测的PH值数据为例,进行水质预测,通过与传统的GA-BP神经网络以及BP神经网络的水质预测模型对比,结果表明,这种预测方法训练的BP神经网络收敛速度快,样本逼近精度高且泛化能力强。     

免疫粒子群算法优化的环境空气质量评价方法

为了提高免疫算法的收敛速度,将粒子群优化思想引入到免疫算法中,设计了一种免疫粒子群优化算法。采用该算法对大气污染损害公式的参数进行寻优,得到了适用于臭氧、PM2．5等6种大气污染物的环境空气质量评价的污染损害指数公式及环境空气质量评价模型。为了使评价结果更准确,采用了国家环保部最新发布的空气质量标准中给出的大气污染物种类、数目及各级浓度限值。将该评价方法应用于大气质量评价领域,实验结果表明,该方法评价结果准确,具有较好的灵活性、实用性和应用前景。     

A new simple method with high precision for determining the toxicity of antifouling paints on brine shrimp larvae (Artemia): first results

The use of antifouling paints is the only truly effective method for the protection of underwater structures from the development of fouling organisms. In the present study, the surface to volume concept constitutes the basis for the development of a new and improved method for determining the toxicity of antifouling paints on marine organisms. Particular emphasis is placed on the attainment of a standardized uniformity of coated surfaces. Failure to control the thickness of the coat of paint in previous studies of this type, has led to inaccurate evaluation of the relative toxicity of samples. Herein, an attempt is made to solve this problem using a simple technique which gives completely uniform and smooth surfaces. The effectiveness of this technique is assessed through two series of experiments using two different types of test containers: 50 ml modified syringes and 7 ml multiwells. The results of the toxicity experiments follow a normal distribution around the average value which allows to consider these values as reliable for comparison of the level of toxic effect detected with the two types of test containers. The mean lethal concentration L(S/V)(50) in the test series conducted in the multiwells (20.38 mm(2)ml(-1)) does not differ significantly from that obtained in the test series using modified syringes (20.065 mm(2)ml(-1)). It can thus be concluded from this preliminary study that the new method and the two different ways of exposing the test organisms to the antifouling paints and their leachates gave reliable and replicable results.     

A review on the usage of POP pesticides in China, with emphasis on DDT loadings in human milk

This article attempts to review the usage of nine pesticides included in the 12 Stockholm Convention persistent organic pollutants (POPs) in China and to examine the extent of DDT contamination in human milk, focusing on the Chinese populations. By comparing all the data available concerning DDTs in human milk from 19 countries, it is revealed that the Chinese populations exhibit rather high concentrations of DDTs, due to the fact that China has been a major producer and consumer of DDTs in the past, and also uses DDT for vector control, resulting in higher background levels of DDTs in different ecological compartments. The high body loading of DDT in Chinese populations is also related to the high dietary intake due to contamination of food. When comparing the data obtained recently (1998-2002), the coastal populations such as Guangzhou (DDE+DDT 2.13 microgg(-1) fat), Hong Kong (2.87 microgg(-1) fat) and Dalian (2.13 microgg(-1) fat) contain higher concentrations of DDTs which may reflect the dietary difference of consuming more meat and fish, than other Chinese populations (Beijing 1.96 microgg(-1) fat; Shenyang 0.87 microgg(-1) fat). In general, the rather low ratio of DDE/DDT (e.g., 4.07 for Guangzhou) of the Chinese milk samples reflected the more recent releases of DDT. It is recommended to impose a tighter control on the use of DDT for vector control as well as for agricultural application, conduct regular monitoring of DDT concentrations in different ecological compartments which include air, water, sediment and biota. Human milk is a preferred indicator reflecting human body loadings of POPs including DDTs, as well as the risk which may impose on our next generation. A national wide survey is needed to investigate the intake of POPs, including POP pesticides, due to dietary differences, with a strong focus on the more sensitive populations, e.g., coastal residents who consume a large amount of fish.     

A review of frameworks for using bryophytes as indicators of climate change with special emphasis on Sri Lankan bryoflora

Environmental Science and Pollution Research - The tropical island of Sri Lanka, with a land area of 65,610 km2 and 1340 km of coastline, is highly vulnerable to impacts of climate change, with...     

A critical review with emphasis on recent pieces of evidence of Moringa oleifera biosorption in water and wastewater treatment

Environmental Science and Pollution Research - The increasing demand for using competent and inexpensive methods based on biomaterials, like adsorption and biosorption, has given rise...     

一种兼顾水质目标和成本投入的流域减排措施优化方法

综合考虑断面水质及治污成本,构建流域治污减排措施优化模型,分析单位污染物去除成本与断面水质改善间的关系,并以承德市武烈河流域治污减排优化为例,绘制治污减排措施优化曲线,提出优化方案。结果表明,在达到流域水质要求的情况下,优化后,治污减排项目由34项缩减到22项,平均单位COD去除成本由1.44万元/t下降到0.65万元/t,同时实现了流域水质达标和降低投入成本的要求。