Enhancing anoxic denitrification of low C/N ratio wastewater with novel ZVI composite carriers

External organic carbon sources are needed to provide electron donors for the denitrification of wastewater with a low COD/NO₃^--N（C/N） ratio, increasing the treatment cost. The economic strategy is to enhance the bioactivity and/or biodiversity of denitrifiers to efficiently utilize organic substances in wastewater. In this study, novel zero-valent iron（ZVI） composite carriers were prepared and implemented in a suspended carrier biofilm reactor to enhance the bioactivity an...     

A field study on residues of four insecticides used in strawberry protection

Abstract

In 1986 strawberry plots were treated with dimethoate, malathion, permethrin and cypermethrin at 80% bloom of primary flowers. In 1987 the plots were sprayed with dimethoate, malathion and permethrin at 30% bloom. Residue analysis of these insecticides on the flowers were analyzed using solvent extraction and gas liquid chromatography. Residue analysis at 0 to 18 days on flowers and fruit showed an exponential decrease. Organophosphates tended to degrade more quickly than synthetic pyrethroids. The results are discussed in the context of an integrated pest management program.     

Socio-Economic Stakes and Perceptions of Wetland Management in an Arid Region: A Case Study from Chott Merouane, Algeria

The objective of our study was to identify how actors from the main socio-economic sectors perceive their interactions and impacts on a sensitive wetland in an arid climate, specifically the salt pans of Chott Merouane in Algeria. The results revealed that there are three main economic stakes including agriculture, livestock production and salt mining, each activity providing a great benefit for local and national populations. The local population perceived that the current activities are conducted in such a way that they created conflict between socio-economic sectors and caused a threat for long term sustainability of the wetlands. The results highlighted the need to initiate an integrated management approach between the different sectors and to develop a shared vision for the territory.     

Policy and Science Implications of the Framing and Qualities of Uncertainty in Risks: Toxic and Beneficial Fish from the Baltic Sea

Policy and research issues in the framing and qualities of uncertainties in risks are analyzed, based on the assessments of dioxin-like compounds (DLCs) and other ingredients in Baltic Sea fish, a high-profile case of governance. Risks are framed broadly, to then focus on dioxins and beneficial fatty acids, fish consumption, human health, and science-management links. Hierarchies of uncertainty (data, model, decision rule, and epistemic) and ambiguity (of values) are used to identify issues of scientific and policy contestation and opportunities for resolving them. The associated complexity of risks is illustrated by risk–benefit analyses of fish consumption and by evaluations of guideline values, highlighting value contents and policy factors in presumably scientific decision criteria, and arguments used in multi-dimensional risk and benefit comparisons. These comparisons pose challenges to narrow assessments centered, for e.g., on toxicants or on food benefits, and to more many-sided and balanced risk communication and management. It is shown that structured and contextualized treatment of uncertainties and ambiguities in a reflexive approach can inform balances between wide and narrow focus, detail and generality, and evidence and precaution.     

Substance-related environmental monitoring

Background  Due to the requirements of the EU Water Framework Directive and other legal regulations (e.g., national laws like the German Federal Soil Protection Act), but also due to the implementation of the new EU chemicals management system REACH, environmental monitoring will gain increasing importance for the surveillance of environmental quality as well as for the assessment of chemicals. Against this background, the Work Group on ‘Environmental Monitoring’ of the Division of ‘Environmental Chemistry and Ecotoxicology’ within the German Chemical Society has compiled a position paper on substance-related environmental monitoring. Scope  Core elements of this position paper are the definitions of important terms like monitoring, exposure monitoring, effect monitoring, and integrated monitoring. Moreover, temporal and spatial aspects (monitoring of spatial distributions, trend monitoring, and retrospective monitoring) and their applications are discussed. The main focus of this position paper is the coverage of aspects which have to be observed for the preparation and implementation of a monitoring program. Essential is the clear specification of the targets of the monitoring which determine the development of the monitoring concept and its realization, e.g., if environmental media (compartments) or organisms are most appropriate as samples for the aim of the study. Of course, also the properties of the target substances are important (e.g., lipophilicity/bioaccumulation as pre-requisite for an exposure monitoring with organisms). Finally, the monitoring phases of sample planning, sampling, storage and transport of samples, selection of analytical methods, quality assurance measures as well as reporting are discussed. Perspectives  An important issue for the future is to link the quantification of chemicals in environmental compartments (exposure and pollution monitoring) more closely to the study of biological effects (effect monitoring) than has been the case up to now. Furthermore, by inclusion of a spatial differentiation, a comprehensive evaluation of the state of an ecosystem can be obtained and the relevance of the results improved. Practical examples of monitoring studies which illustrate various aspects covered in this position paper will be presented in a series of publications by members of the Work Group in the following issues of this journal.

中波发射台电磁辐射环境影响理论预测与模拟类比方法的比较分析

中波台发射设备项目电磁辐射环境影响评价采用理论计算和模拟类比方法结果一致,运用理论计算方法评价结果相对偏安全。     

Policy integration for adaptive water governance: Learning from Scotland's experience

This paper contributes to on-going attempts at bringing together two influential ideas in water governance: Integrated Water Resource Management (IWRM) and adaptive governance. In particular, a tension remains between the call in IWRM for the use of formal institutions, such as river basin organisations, to secure public policy integration, and the assumptions in adaptive governance in favour of informal collaboration between essentially independent policy actors. To clarify this relationship, this article draws on theoretical research on public policy integration, and uses these insights in an empirical setting to identify mechanisms that can facilitate effective policy integration for adaptive water governance. The research is based on recent attempts in Scotland to implement IWRM ideas to improve flood management. Several governance mechanisms were adopted to facilitate the integration of flood, water and rural land use policies. Six Scottish policy regimes are analysed using documentary sources and interviews. Results challenge the idea that collaboration should primarily be built on either river basin organisations or informal mechanisms. We identify a mix of informal and statutory-based mechanisms which may secure political and technocratic commitment to policy integration.     

中小型制革企业综合废水处理工程的设计与应用

采用载体固体床为主要处理单元，辅以高效混凝剂处理中小型制革综合废水，工程运行表明：在进水CODcr,SS,S^2-，总铬的平均浓度在762mg/L,732mg/L,31mg/L,15mg/L的条件下，排水中的CODcr,SS,S^2-，总铬平均浓度为129mg/L,95mg/L,0.47mg/L,0.8mg/L。处理后的水质达到了GB8978-1996《污水综合排放标准》中的Ⅱ级标准。     

Modelling the responses of the Lagoon of Venice ecosystem to variations in physical forcings

A Finite Element Ecological Model for the Lagoon of Venice (VELFEEM) has been used to test the responses of the Lagoon of Venice ecosystem to variations in physical conditions.The model is obtained by coupling a finite element hydrodynamic model, that computes the velocity fields of water, an energetic model to compute the water temperature fields, and an ecological model that simulates the dynamic of phytoplankton, zooplankton, nutrients (ammonia, nitrate and phosphate) organic detritus (organic nitrogen, organic phosphorous and CBOD) and dissolved oxygen.The transport model is a two-dimensional barotropic finite element model which allows for a better resolution of the lagoon morphology.The ecological model has been developed by starting from the ecological module EUTRO of WASP (Water Analysis Simulation System released by US EPA), and by adapting it to the peculiarity of the Lagoon of Venice.A reference condition has been identified by running a 1-year simulation under climatologic condition. Then, the sensitivity to physical forcing (tide and wind) and to the input of macronutrients has been investigated, by comparing model predictions of spatial and temporal evolution of major state variables and of an aggregate index of Water Quality Trophic Index (TRIX).     

Optimisation algorithms for spatially constrained forest planning

We compared genetic algorithms, simulated annealing and hill climbing algorithms on spatially constrained, integrated forest planning problems. There has been growing interest in algorithms that mimic natural processes, such as genetic algorithms and simulated annealing. These algorithms use random moves to generate new solutions, and employ a probabilistic acceptance/rejection criterion that allows inferior moves within the search space. Algorithms for a genetic algorithm, simulated annealing, and random hill climbing are formulated and tested on a same-sample forest-planning problem where the adjacency rule is strictly enforced. Each method was randomly started 20 times and allowed to run for 10,000 iterations. All three algorithms identified good solutions (within 3% of the highest found), however, simulated annealing consistently produced superior solutions. Simulated annealing and random hill climbing were approximately 10 times faster than the genetic algorithm because only one solution needs to be modified at each iteration. Performance of simulated annealing was essentially independent of the starting point, giving it an important advantage over random hill climbing. The genetic algorithm was not well suited to the strict adjacency problem because considerable computation time was necessary to repair the damage caused during crossover.