水平潜流人工湿地氮磷去除回归方程的建立

为考察水平潜流人工湿地对于生活污水中主要污染物指标TN、TP的去除率,建立更为详细的人工湿地回归方程,用以指导人工湿地设计,按照黑箱模型理论,将搜集的500多组数据按照季节、水力负荷、种植植物类型等分类,分析不同因素对于人工湿地去除效果的影响,确定了以季节和水力负荷作为建立回归方程的最主要分类依据.以此为基础,按照线性回归的方法,建立了TN、TP去除率回归方程共12组,所得的拟合优度R2值在0.65~0.95之间,精确性有了很大提高.     

铁氧体对活性污泥法处理生活污水的强化作用

为了提高活性污泥法处理生活污水的效率,采用铁氧体与生物法相结合方式处理生活污水。在生物反应器中投加磁化后的铁氧体粉末,在一定条件下驯化活性污泥。通过试验,得出了铁氧体的最佳投加量为375 mg/L。同普通活性污泥法相比,投加了375 mg/L铁氧体粉末的活性污泥对生活污水中COD和NH3-N的去除率分别提高了4.7%和26.5%;在各自的最佳运行条件下,投加铁氧体后反应器的水力停留时间缩短1 h。     

广西龙布排泥库地下水多元示踪试验研究

以具有复杂水文地质背景的广西平果铝业公司龙布排泥库为研究区．采用钼酸铵、萤光素钠和氯化锌三种试剂．综合考虑各种水文地质条件和其它影响因素．在测区48km^2范围内,布置投放点3个．接收点19个,进行地下水多元示踪试验,为该尾矿库的设计与建设提供必要的水文地质依据,分析库内与库外的地下水水力联系情况,尤其库内与布见水库的水力联系情况,并计算地下水流速,确定地下水流向的主导方向,对于评价该尾矿库对布见水库水源的污染情况具有重要意义。     

Losers in the ‘Rock-Paper-Scissors’ game: The role of non-hierarchical competition and chaos as biodiversity sustaining agents in aquatic systems

Processes occurring within small areas (patch-scale) that influence species richness and spatial heterogeneity of larger areas (landscape-scale) have long been an interest of ecologists. This research focused on the role of patch-scale deterministic chaos arising in phytoplankton assemblages characteristic of “Rock-Paper-Scissors” population dynamics (i.e., competitively non-hierarchical). We employed a simple 2-patch model configuration with lateral mixing and through-flow, and tested the robustness of species richness at the scale of the landscape and spatial heterogeneity. Three different assemblages were used that in a dimensionless box model configuration exhibited chaotic behavior. Our results showed that when a spatial dimension was added to the model configuration, and when all species were shared between patches (i.e., no invading populations), chaos-induced species richness and spatial heterogeneity were quickly reduced with the onset of mixing. While assemblages in each patch were comprised of exactly the same species, they differed in their proportional population densities due to differing stages of succession and the incidence of alternative assemblage structures. Even at very low mixing rates (0.001 d⁻¹), which produced low passive migration rates (0.1% of the total biomass per day), the incidence of high richness and heterogeneity decreased by ∼80%. Interestingly, this sensitivity was not the same for the three assemblages tested. Declines in species richness and spatial heterogeneity associated with mixing were greater in assemblages comprised of competitively dissimilar species (based on the area occupied in the resource-tradeoff space defined by the R* model). The underlying mechanisms may involve the degree to which nutrient dynamics are altered with the arrival of immigrants. Our findings suggest that in partially to well-mixed aquatic systems, the roles of patch-scale non-hierarchical competition and chaos as factors maintaining species richness and spatial heterogeneity may be limited. However, in aquatic systems that experience periods of very low mixing, or even disconnection, non-hierarchical competition and chaos might indeed contribute significantly to biodiversity.     

梯级河滩湿地模型对受污染河水氮磷和CODCr的净化效果

在贾鲁河畔构建3组并联的梯级河滩湿地模型,引种9种不同类型的湿地植物进行筛选试验,将湿地模型串联运行比较研究3种不同植物配置的梯级湿地对受污染河水的净化效果,在此基础上设定12h和24h等两组不同水力滞留时间,研究延长滞留时间对水质净化效果的影响。试验结果表明：对氮磷和有机物的去除效果挺水植物明显好于沉水植物,其中茭草（Zizania caduciflora）、荆三棱（Scirpus fluviatilis）和狭叶香蒲（Typha angustifolia）去除效果最好;沉水植物和挺水植物对氨氮的去除表现好于浮叶植物;延长水力滞留时间对改善水质净化效果明显,滞留时间由12h延长到24h后,TN、TP、氨氮和CODCr去除率分别提高10.2%、21.7%、30.2%和12.9%,对氨氮的净化效果改善最为明显;挺水植物＋沉水植物＋浮叶植物组合较单纯挺水植物组合在对氨氮和TN去除效果方面表现出较明显的优势,主要是由于不同类型湿地植物所营造的好氧、厌氧环境提高了对氨氮和TN去除效果。研究结果证明在湿地植被组建中,根据进水水质,应灵活选择植物种类,进行合理的植物配置,可提高湿地的净化效果。     

RIVER DYE GAGING1

Procedures have been developed (a) to inject a tracer at a constant rate below the water surface at selected points across a stream and (b) to deal with suspended sediment. Mixing remained far from complete in relatively long channels, owing to channel and flow divergence with uncertainty where to sample downstream and which marginal sample values to include for flow calculation. These problems are encountered when mixing is largely dependent on transverse diffusion. Accurate and replicable results were obtained where dye was injected upstream and detected downstream from riffles that induced thorough turbulent mixing. Dye gaging should be practical in gorges or wherever flow is turbulent across the whole width of a channel.     

Mixing Zone Characterization of Two Transition Terrain Streams With Tracers1

Abstract: For most wastewater discharges to streams, the effluent creates a plume that becomes less distinct as it mixes with the receiving water. Constant‐discharge tracer studies were used to characterize the plume or physical mixing zone (PMZ) at two similar transition terrain streams. At both sites, the laterally unmixed PMZs did not extend across the entire stream and mixing occurred relatively quickly. The observed plumes were significantly smaller than the regulatory mixing zone (RMZ) allowed by the State of Colorado. At Site 1 mixing occurred within a much shorter distance due to the presence of a riffle zone located a few meters downstream of the discharge point. Interpretation of field data with an analytical model suggests that the effective transverse dispersion coefficient (k_z) for the riffle zone at Site 1 (～1 m²/s) was significantly higher than the average value over the longer nonriffle section at Site 2 (～0.01 m²/s). These results imply that to achieve the fastest mixing in transition terrain streams, thereby minimizing the size of the PMZ, discharge outfalls should be located upstream and close to riffle zones.     

A NUMERICAL ESTUARINE FLOW MODEL1

A novel estuarine flow model is proposed. It provides some two-dimensional features while using an essentially one-dimensional approach. The model is applied to the Upper Delaware Estuary, and is shown to match available field data with acceptable accuracy. The model is shown to be numerically stable and reasonably mass conservative.     

地面水(河流)环境影响评价中水质模式选择

本文定性分析了连续排放污染物于均匀平直河流中的扩散过程,并对其划分出三个混合阶段,分别给出相应的水质模式,并重点描述了横向混合阶段所预测的主要内容,并根据预测断面所处的混合阶段,提出水质模式的选择方法。     

水力停留时间和搅拌速率对搅拌反应器回收尿液中磷的研究

鸟粪石沉淀法可以在搅拌反应器中回收尿液中的磷,而水力停留时间和搅拌速率对鸟粪石晶体的形成有重要影响.因此,本文在搅拌反应器中通过分批实验研究了水力停留时间(0.5、1.0和2.0 h)和搅拌速率(80、160和320 r·min-1)对尿液中磷的回收率和鸟粪石晶体粒径的影响.结果表明,水力停留时间从0.5 h增至2 h时,磷回收率从88.9%增至95.4%,而鸟粪石晶体平均粒径从124.4μm下降为71.2μm.随搅拌速率从80 r·min-1增至320 r·min-1,磷回收率从88.7%增至93.4%,而鸟粪石晶体平均粒径从37.0μm增至78.9μm.较短的水力停留时间和较高的搅拌速率更有利于大粒径的鸟粪石晶体形成,但对磷回收率影响有限.搅拌速率为160 r·min-1时,鸟粪石回收率最高为78.7%,可以得到纯度很高的鸟粪石晶体,而较高和较低的搅拌速率都不利于提高鸟粪石回收率.