城市污水预水解对二级生化处理的影响

为考察预水解对后续二级生化处理的影响,结合无锡市城北污水处理厂实际运行情况进行了生产性试验研究。结果表明,对于工业废水占40%的城市污水而言,原水经过水解预处理后的可生化性得到提高,并且由于水解池在未满负荷运行的情况下对碳源有机物的去除率较高,对后续硝化脱氨、反硝化脱氮和除磷存在不同的影响。     

Studying ecological communities from a neutral standpoint: A review of models’ structure and parameter estimation

Neutral models provide an alternative to niche-based assembly rules of ecological communities by assuming that communities’ properties are shaped by the stochastic interplay between ecological drift, migration and speciation. The recent and ongoing interest about neutral assumptions has produced many developments on the theoretical side, with nevertheless limited echoes in terms of analyses of real-world data. The present review paper aims to help bridge the widening gap between modellers and field ecologists through two objectives. First, to provide a multi-criteria typology of the main neutral models, including those from population genetics that have not yet been transposed to ecology, by considering how the fundamental processes of ecological drift, speciation and migration are modelled and, specifically, how space is taken into account. Second, to review methods recently proposed to estimate models parameters from field data, a point that should be mastered to allow for broader applications.     

不同标准对城市土壤重金属质量分数的评价

对广州市某区城市土壤重金属污染现状进行调查,共采集土壤样品34个,分析样品中As,Hg,Cr,Cd,Ni和Pb的全量及有效态质量分数,探讨重金属元素全量和有效态质量分数之间的关系,并采用4种不同标准对结果进行了评价. 结果表明:研究区工业用地、城区和农村居住区的土壤已受到一定程度的重金属污染,且为2种或3种重金属元素的复合污染;As,Hg,Cr,Cd,Ni和Pb有效态质量分数平均值分别为0.09,0.004,0.09,0.18,0.40和32.80 mg/kg,Cd和Pb的有效态质量分数占全量的比例较高. 4种标准综合评价结果中,轻度、中度和重度污染样点数占样点总数的比例依次为国标(GB15618—1995)二级标准评价(62%)>有效态污染起始值评价(29%)>全量污染起始值评价(24%)>国标三级标准评价(21%).      

南京市内河道沉积物中重金属元素形态及Pb稳定同位素组成

采集南京市居住和商业区内的河道沉积物,研究重金属元素的形态分布及Pb稳定同位素组成,探讨城市河道沉积物中重金属的迁移潜力和推断污染特征. 沉积物中重金属改良的BCR三步顺序提取研究表明,沉积物中Cd和Zn主要分布于酸溶态;Pb和Cu主要分布于可氧化态;Ni和Cr主要分布于残渣态. Cd和Zn的环境效应最值得关注,而Ni和Cr环境影响最小. 沉积物中m(208Pb)/m(206Pb)和m(206Pb)/m(207Pb)分别为2.102 4～2.123 9和1.159 3～1.184 5. 居住和商业区内的河道沉积物Pb稳定同位素组成相近,具有相似污染源. 居住和商业区内沉积物的Pb稳定同位素比率与文献中南京大气、城市土壤Pb稳定比率相似,因而河道沉积物重金属富集与城市重金属污染密切相关.      

一体化膜生物反应器处理低C/N污水试验研究

研究一体化连续流间歇曝气膜生物反应器(IMBR)处理低C/N城市污水的工艺效能。试验结果表明:反应器在曝气2 h、搅拌2 h的运行模式下,对COD、NH4+-N、TN和SS的平均去除率分别达到了87%,83.4%,75.4%和97.81%,各出水质量浓度平均值分别为17.5,4.59,7.63和2 mg/L,出水水质达到了GB/T18920-2002《城市污水再生利用城市杂用水水质》标准。     

Challenges of simulating complex environmental systems at the landscape scale: A controversial dialogue between two cups of espresso

With the advancement of computational systems and the development of model integration concepts, complexity of environmental model systems increased. In contrast to that, theory and knowledge about > environmental systems as well as the capability for environmental systems analyses remained, to a large extent, unchanged. As a consequence, model conceptualization, data gathering, and validation, have faced new challenges that hardly can be tackled by modellers alone. In this discourse-like review, we argue that modelling with reliable simulations of human-environmental interactions necessitate linking modelling and simulation research much stronger to science fields such as landscape ecology, community ecology, eco-hydrology, etc. It thus becomes more and more important to identify the adequate degree of complexity in environmental models (which is not only a technical or methodological question), to ensure data availability, and to test model performance. Even equally important, providing problem specific answers to environmental problems using simulation tools requires addressing end-user and stakeholder requirements during early stages of problem development. In doing so, we avoid modelling and simulation as an end of its own.     

矿区砷污染对土壤线虫群落结构特征的影响

对湖南省石门县雄黄矿区不同As污染程度土壤线虫群落结构特征进行了研究.共获得线虫27属,食真菌线虫滑刃属(Aphelenchoides)在3种土壤中均为优势属.食细菌和食真菌线虫分别为低As和中As土壤的优势营养类群,而植物寄生线虫为高As土壤的优势营养类群.低As和中As土壤的自由生活线虫成熟度指数(IM)和瓦斯乐斯卡指数(IW)显著高于高As土壤,但植物寄生线虫成熟度指数(IPP)和IPP/IM比值则表现出相反的趋势.可见,高As土壤的食物网受到As污染的干扰较大,群落环境质量较差.因此,土壤线虫群落结构对土壤质量或生态系统的变化具有很好的生物指示作用.     

基于能值-生命力指数的城市生态系统健康集对分析

综合考虑城市的生命体特征及物质能量代谢层面因素,依托城市生命力指数框架,结合能值指标,构建城市能值-生命力指数,以全面反映城市生态系统健康状况.引入集对分析这种不确定理论与方法,比较城市生态系统相对健康状况.采用基于集对分析的城市能值-生命力指数综合评价模型及信息熵权重,比较北京、上海、武汉、广州等16个城市的生态系统相对健康状况,结果表明,厦门、青岛、杭州、上海、北京健康水平相对较高,而乌鲁木齐、成都、哈尔滨健康水平相对较低,其他城市则为中等水平.     

合肥城市绿地土壤特点

以合肥市一环内绿地土壤和近郊蜀山森林公园土壤为对象,研究了土壤表层0~10 cm的理化特性,分析了全磷与速效磷,速效磷与潜在酸度之间的关系。结果表明,市区绿地土壤的容重平均值为1.41 kg/cm3,土壤电导率显著高于近郊森林土壤;城市绿地土壤pH值多在7.51~8.50之间,与森林土壤相比,碱性化趋势明显;城市土壤具有明显的富磷和贫氮特征,其全氮含量平均值为1.44 g/kg,全磷含量平均值为792.0 mg/kg、速效磷含量为50.6 mg/kg,分别是近郊森林土壤的0.64倍、2.9倍和5.1倍;城市土壤全磷与有效磷含量呈显著的正相关(r=0.79,p=0.000);潜在酸度与有效磷含量呈显著负相关(r=0.65,p=0.000)。     

TECIIMQUES FOR DETECTING HYDROLOGIC CHANGE IN HIGH RESOURCE STREAMS1

ABSTRACT: A “synthetic paired basin” technique that combines hydrologic monitoring and watershed modeling proves to be a useful tool in detecting hydrologic change in creeks draining basins undergoing urbanization. In this approach, measured stream flow following subbasin treatment (a period of urbanization) is compared with flow from a control subbasin over the same time period. The control subbasin is the pretreatment subbasin itself as represented by a well‐calibrated hydrologic model that is input with post‐treatment meteorological data. The technique is illustrated for stream monitoring sites at the outlets of two high‐resource sub‐basins in the Bear Creek basin of King County, Washington. Application of this technique holds promise to provide earlier warning of cumulative, human impacts on aquatic resources and to better inform adaptive watershed management for resource protection.