Calculation of the minimum ecological water requirement of an urban river system and its deployment: A case study in Beijing central region

The minimum ecological water requirements of an urban river system and water deployment are key elements in integrated water resources planning and urban ecological construction. Based on a review of ecological water requirement calculation methods and considering the different ecological functions of an urban river system, the ecological function method was used in this paper to calculate the components of the ecological water requirements of an urban river. An envelope curve-based method was proposed for assessing the minimum ecological water requirements of an urban river system. Water resources deployment strategies designed to meet the minimum ecological water requirements were described. Then, the minimum ecological water requirements of the urban river system in Beijing central region, selected as a case study, were investigated. The key parameters for assessing the minimum ecological water requirement in the Beijing urban river system were determined. Based on the ecological objectives and the current status of the different urban river systems within the Beijing central region, the minimum ecological water requirements were calculated. Different types of water sources, including rainwater, upstream water, and reclaimed water, were deployed to meet the ecological water requirements for the urban river system in the Beijing central region.     

Model parameterization for aerobic decomposition of plant resources drowned during man-made lakes formation

The formation of man-made reservoirs generates several impacts on water quality. In order to minimize some of these impacts mathematical models are currently used. This paper aims to discuss the issue associated with the degradation of plant resources (leaves, branches, barks and litter) that remain within the watershed of the new man-made lakes and parameterize a kinetic model related to decay of plant detritus. In these environments, the short-term variation of limnological parameters is mainly connected with biomass decay drowned during the filling operation. The kinetics of the degradation processes in reservoirs are discussed on the basis of information with related to detritus sources and the chemical properties of different types of compounds (i.e. labile and refractory fractions). Overall, the parameterization of the (first order) kinetic model showed that refractory fractions (ca. 86%) are predominant and the mineralization is a slow process, constituting the main route for decomposition and being affected by changes of environmental variables. The mineralization of labile and hydrosoluble compounds (ca. 14%) is responsible for the short-term water quality variation owing to decomposition; basically, the intensities of these changes depend on the labile/soluble compounds content of detritus and its chemical composition.     

An effective technique for wastewater minimisation in batch processes

This paper presents a mathematical formulation for freshwater and wastewater minimisation in multipurpose batch plants. The minimisation of wastewater is achieved through the exploitation of recycle and reuse opportunities. A superstructure that entails all possible recycle and reuse possibilities is used as the basis for the formulation. The existence of an optimal production schedule, which provides starting and finishing times for water using operations, is assumed. The paper addresses the specific case where the contaminant concentration in the outlet water stream from each operation is maintained at its maximum. This condition allows the overall model to be cast as a mixed integer linear programming (MILP) problem for which global optimality is guaranteed. The effectiveness of the developed formulation is demonstrated through a published literature example and a practical case study.     

石油化工废水的预处理试验研究

石油化工废水的浓度较高，其中某些组分可生化性低。采用空气吹脱法可去除其中定量低沸点有机溶剂，从而极大降低废水的有机物浓度，并可提高废水的可生化性。本文重点讨论了不同参数条件对废水预处理效果的影响，得出了最佳工艺参数。     

Field bioassessments for selecting test systems to evaluate military training lands in tallgrass prairie. Ecosystem health. V

Ecosystem responses to physical or chemical stress may vary from changes in single organisms to alteration of the structure and function of the ecosystem. These responses to stress cannol be predicted exactly. Ecosystems repeatedly exposed to physical and/or chemical stress can be used to study the separate and combined environmental effects of stress. Such studies also allow the development of procedures to select test systems for the analysis of stress in ecosystems. A preliminary field survey of six military training sites at Fort Riley, Kansas, USA, was conducted to identify and verify ecological test systems for evaluating ecosystem responses to physical and/or chemical stress. Comparisons of these data with data collected concurrently from Konza Prairie Research Natural Area reference sites showed that soil microarthropods, some species of macroarthropods, small mammals, and native earthworm species were negatively affected by stress. In contrast, plant species diversity, plant foliage biomass, soil mycorrhizae, and many soil characteristics were within the boundaries of nominal variations observed on “pristine” Konza Prairie. Introduced European earthworms appeared to be positively affected by training activities. This study provided a test of systematic procedures to support impact analysis, ecological toxicology, and ecosystem risk assessments. This is paper IX in D. J. Schaeffer's “Environmental Audit” series.     

国内外辛醇生产中废水处理方法探讨

探讨了国内外辛醇生产中废水处理方法，对于较先进的酸化萃取法和厌氧曝气吸附法作了细致的介绍，并对各种处理方法进行对比分析，为我国辛醇生产废水处理提供有价值的技术信息。     

黄磷诱发氧化新技术

黄磷诱发氧化是一种有效的氧化方法，已开始应用于气相和液相污染控制。反应过程中生成一系列活性物种，臭氧是其中之一。黄磷诱发氧化反应主要在气相中进行，多相间接触条件是反应的关键因素。考察了对两种典型有毒物多氯联苯和三甲基环已烯酮的氧化效果，两小时左右，去除率达９０％以上。这项新技术具有设备简单、条件缓和等优势，因而有一定的应用前景，并对开拓新的氧化领域具有重要意义。     

Functional relationship between ammonia-oxidizing bacteria and ammonia-oxidizing archaea populations in the secondary treatment system of a full-scale municipal wastewater treatment plant

The abundance of ammonia-oxidizing bacteria and archaea and their amoA genes from the aerobic activated sludge tanks, recycled sludge and anaerobic digesters of a full-scale wastewater treatment plant (WWTP) was determined. Polymerase chain reaction and denaturing gradient gel electrophoresis were used to generate diversity profiles, which showed that each population had a consistent profile although the abundance of individual members varied. In the aerobic tanks, the ammonia-oxidizing bacterial (AOB) population was more than 350 times more abundant than the ammonia-oxidizing archaeal (AOA) population, however in the digesters, the AOA population was more than 10 times more abundant. Measuring the activity of the amoA gene expression of the two populations using RT-PCR also showed that the AOA amoA gene was more active in the digesters than in the activated sludge tanks. Using batch reactors and ddPCR, amoA activity could be measured and it was found that when the AOB amoA activity was inhibited in the anoxic reactors, the expression of the AOA amoA gene increased fourfold. This suggests that these two populations may have a cooperative relationship for the oxidation of ammonia.     

In situ synthesis of potassium tungstophosphate supported on BEA zeolite and perspective application for pesticide removal

Potassium tungstophosphate is supported on BEA zeolite by in situ synthesis for glyphosate removal. Spectroscopic measurements identified hydrogen bonding as a primal interaction of potassium salt and BEA zeolite. Composites are evaluated for glyphosate herbicide removal and adsorption process is analyzed using two isotherm models. Obtained adsorption capacities for all prepared composites lay between 45.2 and 92.2?mg of glyphosate per gram of investigated composite. Suspension acidity revealed that glyphosate is adsorbed mainly in the zwitter-ion form at the composite surface while the amount of potassium salt in the composites is crucial for the adsorption application. Exceptional adsorption behavior is postulated to come from a high degree of homogeneity among surface active sites which is confirmed by different experimental methods. Temperature programmed desorption of glyphosate coupled with mass spectrometer detected one broad, high-temperature peak which represents overlapped desorption processes from active sights of similar strength. Introduction of potassium tungstophosphate affects active sites present in BEA zeolite for glyphosate desorption and significantly increases the amount of adsorbed pesticide in comparison to BEA zeolite. Supporting of potassium tungstophosphate on BEA zeolite via in situ synthesis procedure enables the formation of highly efficient adsorbents and revealed their perspective environmental application.     

Use of polymeric sub-micron ion-exchange resins for removal of lead, copper, zinc, and nickel from natural waters

This research investigated the removal capacity of polymeric sub-micron ion-exchange resins(SMR) for removal of lead, copper, zinc, and nickel from natural waters in competition with natural organic matter(NOM). Polymeric SMR particles were created and tested to ensure that they were adequately dispersed in the solution. They removed little NOM(10%or less) from river water and wastewater, indicating that competition from NOM was not a major concern. SMR were able to remove 82% ± 0.2% of lead, 46% ± 0.6% of copper, 55% ±20% of zinc, and 17% ± 2% of nickel from river water spiked with 500 μg/L of each. Similarly,in wastewater, they were able to remove 86% ± 0.1% of lead, 38% ± 0.8% of copper, 28% ± 1%of zinc, and 11% ± 1% of nickel.