水环境数学模型与GIS的集成研究

从地理信息系统(GIS)的功能特点、环境信息的特性和水环境数学模型软件应用时存在不足的3个方面分析了GIS和水环境数学模型软件集成的必要性.介绍了GIS和水环境数学模型的集成方式以及苏州河三期综合整治决策支持系统的主要功能结构,重点从GIS和水环境数学模型集成方面介绍了地图矢量化、模型计算结果转化为相应数据库文件、数据库文件和GIS实现绑定以及断面水位动态演示的实现方法和重要作用.     

可视化黄浦江水环境数学模型系统设计与开发

随着信息技术的高速发展,传统的水环境数学模型与数据库技术、GIS技术、可视化编程工具紧密结合,水环境数学模型的可视化是其发展的一个重要趋势,也是开发水环境决策支持系统和水环境数学模型商业软件的重要基础。对可视化水环境数学模型的设计框架进行了初步探讨,并结合自主开发的可视化黄浦江二维水环境数学模型系统,介绍可视化水环境数学模型的设计与开发。     

SBR工艺数学模型研究进展及其应用

SBR法具有操作简单、运行方式灵活、占地面积小等优点,用于处理间歇排放的工业废水及中小城镇污水取得了巨大成功,并在全世界范围内迅速得到发展和推广应用。随着自控技术的飞速发展和对SBR工艺机理的深入认识,围绕SBR工艺数学模型的研究引起各国学者的重视。回顾了目前SBR法数学模型的研究进展和应用现状,并总结和比较了各种数学模型的优势和不足,特别是对机理模型（白箱模型）和统计模型（黑箱模型）进行了分类、归纳和分析。所有这些数学模型建模与仿真的目的都是为了实现SBR工艺优化控制,为实际SBR污水处理厂的运行提供依据和技术支持。虽然以前的研究有力地推动了数学模型在SBR工艺中的应用,但是在实际应用中还存在很多值得深入研究的问题。最后对SBR工艺数学模型尚待解决的问题进行了总结,并指出今后SBR数学模型的发展方向。     

溶解性微生物产物数学模型的研究进展

溶解性微生物产物(SMP)数学模型对于控制废水生物处理出水中COD具有极其重要的作用.按照SMP模型发展过程,即从只包含其形成机制模型到包含其形成与降解机制模型的发展过程,详细介绍了SMP模型的研究进展.同时,综述了SMP数学模型在活性污泥法和生物膜法等工艺中的应用,并在此基础上提出了活性污泥数学模型的发展方向.     

污水处理工艺系统优化设计理论的研究与发展

综述了污水处理工艺系统优化设计理论研究的发展历史 ,分析总结了优化设计模型研究的发展规律以及需要解决的关键性问题 ;详细介绍了几个具有典型代表性的非线性系统优化模型的结构及寻优方法 ;从 6个特征方面横向比较了部分优化数学模型的研究成果 ;结合国内研究动态提出了对该领域研究前景的展望     

污水处理工艺系统优化设计理论的研究与发展

综述了污水处理工艺系统优化设计理论研究的发展历史。分析总结了优化设计模型研究的发展规律以及需要解决的关键性问题；详细介绍了几个具有典型代表性的非线性系统优化模型的结构及寻优方法；从6个特征方面横向比较了部分优化数学模型的研究成果；结合国内研究动态提出了对该领域研究前景的展望。     

大气污染事故预测系统的研究

将地理信息系统应用于城市突发性的大气污染事故，对大气扩散模型的图形技术进行开发研究。介绍了设计的总体结构；详细叙述了数学模型的建立、编程语言及其关键技术。该技术能模拟显示化学品泄漏后的大气污染扩散范围，为应急反应科学决策服务。     

地下水中多环芳烃迁移转化研究

吸附和生物降解是受污染地下水中多环芳烃(PAHs)归宿的主要途径.论述了PAHs在含水层中吸附过程的特征、影响因素与研究方法,并比较各种研究方法的优缺点;分析了PAHs在含水层中生物降解过程机制以及研究进展;介绍了PAHs在地下水中迁移、转化数学模型与数值模拟的研究开发状况;指出了PAHs与固相介质的吸附机制和竞争吸附行为、高分子量PAHs的生物降解途径和机制及共存PAHs或与其他污染物在地下水中的迁移、转化、归宿与修复技术是深入研究的方向.     

多环芳烃的光致毒效应

多环芳烃（ＰＡＨｓ）是一类常见的污染物,过去对其毒性的研究主要集中在生物体内代谢产物的毒效应上。但是近期研究表明紫外光的照射对多环芳烃的毒性具有显著影响,称为ＰＡＨｓ的光致毒效应。本文介绍了多环芳烃在紫外光照射下的急性光致毒作用,致毒作用发生机理及毒性预测的数学模型,同时探讨了ＰＡＨｓ对紫外光致癌性的影响。     

交变磁场涡电流分离回收固废中有色金属资源研究

推导了交变磁场感应涡电流力数学模型 ,找出了影响涡电流分离效果的几个主要因素。涡电流分离条件实验证明了数学模型的正确性。涡电流分离实验的显著效果表明 ,交变磁场涡电流分离技术作为一项具有十分广阔应用前景的固废资源化技术 ,具有重要的研究意义     

不确定性水质模型及其研究进展

水环境是一个充满不确定性因素的复杂巨系统,研究这些不确定性的变化有利于提高人们对水环境分析的认识和做出更切合实际的决策.详细、清晰地评述了不确定性水质模型研究的必要性、研究的方法和国内外研究进展等,并针对此类模型研究与应用过程中普遍存在的一些问题、主要表现和成因进行了分析与论述,最后结合目前的研究热点指出了今后不确定性水质模型发展的3个重要方向.     

Fate of hydrophobic organic pollutants in the aquatic environment: a review

The fate of hydrophobic organic pollutants in the aquatic environment is controlled by a variety of physical, chemical and biological processes. Some of the most important are physical transport, chemical and biological transformations, and distribution of these compounds between the various environmental compartments (atmosphere, water, sediments and biota). The major biogeochemical processes that control the fate of hydrophobic organic compounds in the aquatic environment are reviewed. These processes include evaporation, solubilization, interaction with dissolved organic matter, sediment-water partitioning, bioaccumulation and degradation. Physico-chemical parameters used to predict the aquatic fate of such compounds are also discussed.     

Development of the hybrid cells in series model to simulate ammonia nutrient pollutant transport along the Umgeni River

Discharge of organic waste results in high nutrient pollution of the water bodies which is a major menace to the environment. A high quantity of nutrients such as ammonia causes a reduction in the dissolved oxygen level and induces algal growth in the water bodies. Water quality models have been the tools to evaluate the rate at which streams can disperse the pollutants they receive. Many water quality models are flawed either because of their inadequacy to completely simulate the advection component of the pollutant transport, or because of the limited application of the models, due to inaccurate estimation of model parameters. The hybrid cell in series (HCIS) developed by Ghosh et al. (2004) has been able to overcome such difficulties associated with the mixing cell-based models. Thus, the current study focuses on developing an analytical solution for the pollutant transport of the ammonia concentration through the plug flow, the first and second well-mixed cells of the HCIS model. The HCIS model coupled with the first order kinetic equation for ammonia nutrient was developed to simulate the ammonia pollutant concentration in the water column. The ammonia concentration at various points along the river system was assessed by considering the effects of the transformation of ammonia to nitrite, the uptake of ammonia by the algae, the respiration rate of the algae and the input of benthic source to the ammonia concentration in the water column. The proposed model was tested using synthetic data, and the HCIS-NH₃ model simulations for spatial and temporal variation of ammonia pollutant transport were analysed. The simulated results of the HCIS-NH₃ model agreed with the Fickian-based advection-dispersion equation (ADE) for simulating ammonia concentration solved using an explicit finite difference scheme. The HCIS-NH₃ model also showed a good agreement with the observed data from the Umgeni River, except during rainy periods.     

Extension of coupled multispecies metal transport and speciation (TRANSPEC) model to soil

Atmospheric deposition of metals emitted from mining operations has raised metal concentrations in the surrounding soils. This repository may be remobilized and act as a source of metals to nearby surface aquatic systems. It is important to understand metal dynamics and the impact of various chemistry and fate parameters on metal movement in the soil environment in order to evaluate risk associated with metals in terrestrial ecosystems and accurately establish critical discharge limits that are protective of aquatic biota. Here we extend our previously developed coupled multispecies metal fate-TRANsport and SPECiation/complexation (TRANSPEC) model, which was applicable to surface aquatic systems. The extended TRANSPEC, termed TRANSPEC-II, estimates the partition coefficient, K(d), between the soil-solid and -soluble phases using site-specific data and a semi-empirical regression model obtained from literature. A geochemical model calculates metal and species fractions in the dissolved and colloidal phases of the soil solution. The multispecies fugacity/aquivalence based fate-transport model then estimates inter-media transport rates such as leaching from soil, soil runoff, and water-sediment exchanges of each metal species. The model is illustratively applied to Ni in the Kelly Lake watershed (Sudbury, Ontario, Canada), where several mining operations are located. The model results suggest that the current atmospheric fallout supplies only 4% of Ni removed from soil through soil runoff and leaching. Soil runoff contributes about 20% of Ni entering into Kelly Lake with the rest coming from other sources. Leaching to groundwater, apart from runoff, is also a major loss process for Ni in the soil. A sensitivity analysis indicates that raising soil pH to above 6 may substantially reduce metal runoff and improve water quality of nearby water bodies that are impacted by runoff.     

Management of marine cage aquaculture

Goal, Scope and Background Marine cage aquaculture produces a large amount of waste that is released directly into the environment. To effectively manage the mariculture environment, it is important to determine the carrying capacity of an aquaculture area. In many Asian countries trash fish is dominantly used in marine cage aquaculture, which contains more water than pellet feed. The traditional nutrient loading analysis is for pellet feed not for trash fish feed. So, a more critical analysis is necessary in trash fish feed culturing areas. Methods Corresponding to FCR (feed conversion rate), dry feed conversion rate (DFCR) was used to analyze the nutrient loadings from marine cage aquaculture where trash fish is used. Based on the hydrodynamic model and the mass transport model in Xiangshan Harbor, the relationship between the water quality and the waste discharged from cage aquaculture has been determined. The environmental carrying capacity of the aquaculture sea area was calculated by applying the models noted above. Results Nitrogen and phosphorus are the water quality parameters considered in this study. The simulated results show that the maximum nitrogen and phosphorus concentrations were 0.216 mg/L and 0.039 mg/L, respectively. In most of the sea area, the nutrient concentrations were higher than the water quality standard. The calculated environmental carrying capacity of nitrogen and phosphorus in Xiangshan Harbor were 1,107.37 t/yr and 134.35 t/yr, respectively. The waste generated from cage culturing in 2000 has already exceeded the environmental carrying capacity. Discussion Unconsumed feed has been identified as the most important origin of all pollutants in cage culturing systems. It suggests the importance of increasing the feed utilization and improving the feed composition on the basis of nutrient requirement. For the sustainable development of the aquaculture industry, it is an effective management measure to keep the stocking density and pollution loadings below the environmental carrying capacity. Conclusions The DFCR-based nutrient loadings analysis indicates, in trash fish feed culturing areas, that it is more critical and has been proved to be a valuable loading calculation method. The modeling approach for Xiangshan Harbor presented in this paper is a cost-effective method for assessing the environmental impact and determining the capacity. Carrying capacity information can give scientific suggestions for the sustainable management of aquaculture environments. Recommendations and Perspectives It has been proved that numerical models were convenient tools to predict the environmental carrying capacity. The development of models coupled with dynamic and aquaculture ecology is a requirement of further research. Such models can also be useful in monitoring the ecological impacts caused by mariculture activities. ESS-Submission Editor: Hailong Wang (hailong.wang@ensisjv.com)     

Simulation of transboundary pollutant transport action in the Pearl River delta

The rapid economic development in The Pearl River delta region (PRDR) has exerted serious potential pollution threats to areas in the vicinity, which have complicated the task of environmental protection in Hong Kong and Macau. In this paper, a three-dimensional numerical pollutant transport model coupled with a synchronised numerical hydrodynamic model, is developed and employed to simulate the unsteady transport of a representative water quality variable chemical oxygen demand in The Pearl River Estuary. It is demonstrated that there exists a transboundary pollutant transport action between Guangdong Province and Hong Kong for the pollutants in the wastewater discharged from PRDR.     

Environmental assessment of 5-ethylidene-2-norbornene using modeled and measured fate and effects results

Several predictive models were used to assess aquatic exposure, persistence (P) and potential for long-range transport (LRT) of 5-ethylidene-2-norbornene (ENB). Such estimations are components of the assessment process for persistent, bioaccumulative and toxic (PBT) substances, which are also referred to as persistent organic pollutants (POPs). An ecological exposure assessment for ENB from manufacturing activities was conducted based on physical/chemical properties, monitoring data, and degradation, transport and distribution estimates. Based on the results of several model predictions, chronic exposure of aquatic organisms is not expected, due to the anticipated residence time of ENB in aquatic ecosystems. These modeled results consistently predict ENB does not present the potential to persist in the environment. Volatilization from water to the air is calculated to occur at a relatively rapid rate for ENB based on its Henry's Law constant. Once in the air, ENB is expected to degrade rapidly due to oxidation by hydroxyl radicals and ozone based on calculated atmospheric half-lives of 57 and 27 min, respectively. Additionally, ENB is not predicted to undergo long-range transport based on the short atmospheric half-life due to oxidation by hydroxyl radicals and ozone. Additionally, based on predicted exposure from site-specific emission using the EPA model EFAST, ENB is not expected to reach concentrations of concern for chronic aquatic toxicity endpoints.     

上海市截流外排工程污水扩散影响数值研究

城市污水截流外排工程是上海市城市水环境整治的重大战略。文章以CODCr为例,数值模拟研究了上海近岸水域东、南、西三大截流外排干线不同排污方案下污染物的输移扩散规律。结果表明,长江口的水动力条件有利于污水的稀释扩散;在现状排污条件下,无论洪枯季,引起的环境水体污染物CODCr浓度增量均不大,能够满足长江口水环境容量的要求;对于规划排放量的污水,预处理和一级处理条件下引起的环境水体污染物CODCr,浓度增量较为显著,对周围敏感目标的影响也比较大;二级处理条件下所引起的污染浓度增量比较小,对水环境的影响相对较小。因此,在规划城市污水外排工程时,建议必须近期和远期相结合,合理充分利用水体自净能力。     

Uptake and Modeling of Pesticides by Roots and Shoots of Parrotfeather (Myriophyllum aquaticum) (5 pp)

Intention, Goal, Scope, Background Aquatic plants have a great potential to function as in situ, on-site biosinks and biofilters of pollutants. They are used for phytoremediation and phytotoxicity studies. Pesticide uptake studies are very important to predict contaminant accumulation, translocation, and transformation. There are a lot of models which have been developed for emergent plants, but there are not any existing models for submerged aquatic plants for assessing pesticide uptake. Objective In this study, uptake of selected pesticides in parrotfeather (Myriophyllum aquaticum) were studied and the results were modeled with the aid of Log Kow and the concentration of pesticides. At the end, the developed model was compared to other existing models. Methods The test was conducted with parrotfeather as a model plant. The bioassay and cultivation of this plant were examined. Pesticide uptake by roots and shoots was determined using 14C-radiolabeled materials. Results and Discussion The results were fitted with an equation that showed a relationship between uptake and lipophilicity of pesticides. The model was compared with other pesticide uptake models developed for other plants. Atrazine and cycloxidim were taken up more by roots than by shoots in comparison to other pesticides used. The total uptake, both in shoots and roots, was lower than for terbutryn and trifluralin. The best appropriate model was developed from the results against the other models seen in the literature. The concentration factors (Root Concentration Factor (RCF) and Submerged Shoot Concentration Factor (SSCF)) increased with a higher Kow of the substances. The Submerged Shoot Concentration Factor (SSCF) revealed a better relationship of the chemicals than did the Root Concentration Factor (RCF). Conclusions In this study, an uptake model was developed for rooted, submerged aquatic plants. Further studies are necessary to develop and compare models with different plants and pesticides. Recommendation and Outlook Such studies as this one may be extended to other environmental pollutants in the aquatic ecosystem and may be employed to evaluate the possibility of using different plants in phytoremediation studies.