王哥庄湾陆源硝酸盐氮输送通量研究

以汇水区域相对独立的崂山王哥庄地区为例 ,通过研究该区的水文地质条件、分析地表水和地下水中的硝酸盐氮 (NO3 N) ,采用流量法和断面法分别对河流和地下水向王哥庄湾的NO3 N输送量进行了计算。结果表明 ,1999年 5月下旬地下水向海洋输送的NO3 N占整个陆源输入量的 30 .0 6 % ,说明地下水向海洋的营养盐输送量是海洋环境评估的重要边界条件。     

A pilot scale anoxic/oxic membrane bioreactor (A/O MBR) for woolen mill dyeing wastewater treatment

A pilot-scale( 10 m^3/d) anoxic/oxic membrane bioreactor( A/O MBR) was tested for dyeing wastewater treatment of woolen mill without wasting sludge in 125 days operation. Results showed that the effluent quality was excellent, i.e. effluent COD less than 25 mg/L,BOD5 under 5 mg/L, turbidity lower than 0.65 NTU, and colour less than 30 DT, and met with the reuse water standard of China. The removal rates of COD, BOD5, colour, and turbidity were 92.4%, 98.4%, 74% and 98.9%, respectively. Constant-flux operation mode was carried out in this study, and backwash was effective for reducing membrane fouling and maintaining constant flux. Membrane fouling had heavy impact on energy consumption. More attention should be paid on pipe selection and design for the sidestream MBR system, too.     

投加粉末活性炭对一体式膜-生物反应器膜污染的影响研究

通过试验考察了粉末活性炭（PAC）对一体式膜-生物反应器中膜污染的影响．在2种类型的污泥（膨胀污泥和非膨胀）中，投加适量PAC可以减轻膜污染，表现为临界膜通量的提高和连续运行中膜污染增长速率的降低．当污泥性质和浓度不同时，最佳PAC投加范围亦不同．PAC投量过大会引起临界通量下降．PAC的投加显著降低了混合液中溶解性物质的浓度，减轻了溶解性物质的吸附和膜孔堵塞污染，并改善了絮体结构．污泥比阻与污泥混合液膜过滤性能之间有很好的相关性，可作为污泥混合液膜过滤性能的快速评价指标．     

A hybrid method for inverse characterization of subsurface contaminant flux

The methods presented in this work provide a potential tool for characterizing contaminant source zones in terms of mass flux. The problem was conceptualized by considering contaminant transport through a vertical "flux plane" located between a source zone and a downgradient region where contaminant concentrations were measured. The goal was to develop a robust method capable of providing a statement of the magnitude and uncertainty associated with estimated contaminant mass flux values. In order to estimate the magnitude and transverse spatial distribution of mass flux through a plane, the problem was considered in an optimization framework. Two numerical optimization techniques were applied, simulated annealing (SA) and minimum relative entropy (MRE). The capabilities of the flux plane model and the numerical solution techniques were evaluated using data from a numerically generated test problem and a nonreactive tracer experiment performed in a three-dimensional aquifer model. Results demonstrate that SA is more robust and converges more quickly than MRE. However, SA is not capable of providing an estimate of the uncertainty associated with the simulated flux values. In contrast, MRE is not as robust as SA, but once in the neighborhood of the optimal solution, it is quite effective as a tool for inferring mass flux probability density functions, expected flux values, and confidence limits. A hybrid (SA-MRE) solution technique was developed in order to take advantage of the robust solution capabilities of SA and the uncertainty estimation capabilities of MRE. The coupled technique provided probability density functions and confidence intervals that would not have been available from an independent SA algorithm and they were obtained more efficiently than if provided by an independent MRE algorithm.     

Methane fluxes from tundra soils and snowpack in the maritime Antarctic

Methane fluxes were measured from three exposed tundra sites and four snowpack sites on the Fildes Peninsula in the maritime Antarctic in the summertime of 2002. The average fluxes at two normal tundra sites were −15.3 μg m⁻² h⁻¹ and −14.3 μg m⁻² h⁻¹, respectively. The fluxes from tundra site with fresh penguin dropping addition showed positive values with the average of 36.1 μg m⁻² h⁻¹, suggesting that the deposition of fresh droppings greatly enhanced CH₄ emissions from the poor Antarctic tundra during penguin breeding periods. The summertime variation in CH₄ flux was correlated with surface ground temperature and the precipitation. The correlation between the flux and PT₀, which is the product of the precipitation and surface ground temperature, was quite strong. The diurnal cycle of CH₄ flux from the tundra soils was not obtained due to local fluky weather conditions. The fluxes through four snowpack sites were also obtained by the vertical CH₄ concentration gradient and their average fluxes were −46.5 μg m⁻² h⁻¹, −28.2 μg m⁻² h⁻¹, −46.4 μg m⁻² h⁻¹ and −17.9 μg m⁻² h⁻¹, respectively, indicating that tundra soils under snowpack also consume atmospheric CH₄ in the maritime Antarctic; therefore these fluxes could constitute an important part of the annual CH₄ budget for Antarctic tundra ecosystem.     

膜生物反应器在污水处理中的应用现状及展望

综述了膜生物反应器（MBR）的研究进展，介绍了其分类及特点、处理机理与MBR运行的影响因素以及膜污染的控制等，并概括了MBR的发展及展望。MBR是近来发展较迅速的一种污水治理设备，具有占地少、能耗低等优点，但也存在一定的缺点，其中膜污染是影响其推广应用的主要因素，目前国内外学者一般都以膜污染作为切入点进行研究，通过改变料液性质、优化操作参数、提高膜清洗效率等方法得以防治膜污染。     

Chemical composition of rainwater in the northeastern Romania, Iasi region (2003–2006)

Chemical composition of rainwater was studied in the northeastern Romania, Iasi region, and the concentrations of major inorganic and organic ions were measured in samples collected between April 2003 and December 2006. The pH of the rainwater is 5.92 (volume weighted mean average, VWM) suggesting a sufficient load of alkaline components neutralizing its acidity. On average, 97% of the acidity in the collected samples is neutralized by CaCO₃ and NH₃. Clear seasonal variations were observed for some of the identified ions (e.g., SO₄²⁻, NO₃⁻, Ca²⁺, NH₄⁺). The data obtained during this work revealed that both concentrations and fluxes of anthropogenic source-related ions (e.g., SO₄²⁻, NO₃⁻ and NH₄⁺) are among the highest reported for European sites. It is shown that meteorology and long-range transport processes may concur to their high levels.     

Comment on “Analysis of groundwater contamination using concentration-time series recorded during an integral pumping test: Bias introduced by strong concentration gradients within the plume” by Allelign Zeru and Gerhard Schäfer

We consider the results of a recent paper in this journal [Zeru, A. and Schäfer, G., 2005. Analysis of groundwater contamination using concentration–time series recorded during an integral pumping test: Bias introduced by strong concentration gradients within the plume. Journal of Contaminant Hydrology 81 (2005) 106–124], which addresses the field-scale characterisation of contaminant plumes in groundwater. There, it is concluded that contaminant concentration gradients can bias Integral Pumping Test (IPT) interpretations considerably, in particular if IPTs are conducted in advective fronts of contaminant plumes. We discuss implications of this setting and also argue that the longitudinal and transverse dispersivities used in the examples of Zeru and Schäfer (2005) of up to 30 m and 3 m, respectively, are generally very high for the here relevant capture zone scale (< 20 m). However, regardless of both longitudinal and transverse concentration gradients, we further show through a counter-example that IPT results are unbiased as long as the concentration attenuation along the flow direction is linear over the capture zone extent.     

膜生物反应器生物降解与膜分离共作用特性研究

膜生物反应器实质是生物降解与膜分离相互影响,共同作用的过程,污泥浓度与通量之间存在一定的相关关系,膜分离对生和性能尤其是细菌活性有着重要的影响,而生物反应器内细菌胞外聚合物,溶解性有机物及微细胶体可能成为形成凝胶层导致通量下降的主要因素。     

Calibration and testing of a dynamic flow-through chamber for field determination of methyl bromide volatilization flux

Accurate emission measurement of highly volatile chemicals such as methyl bromide (MeBr) is a crucial step in assessing their potential for environmental contamination. Use of flux chambers is a simple method for measuring emission rate under field conditions. To validate the applicability of a dynamic flow-through chamber for measuring MeBr emission, we provide a complete presentation of calibration and testing of the chamber. The calibration was made under a controlled system subject to ambient temperature changes. Two field experiments were conducted to test the chamber for measuring MeBr flux under conditions similar to commercial soil fumigation practices. In both the calibration and the two field experiments, the chamber provided accurate emission estimates. The maximum mass balance error was < 10% which is comparable to the micrometerological method. Because of its simplicity, we believe this dynamic flux chamber can be used reliably in quantifying the emission dynamics of highly volatile chemicals such as MeBr.