火电厂水平衡优化研究

通过对火电厂水系统供水、需水特性的分析，建立了水系统优化的数学模型，对不同供水、需水条件下的火电厂水系统水平衡进行了优化。模型的优化结果对火电厂水系统的设计和运行管理有一定指导作用。     

95火电厂废水综合治理学术交流会在苏州召开

中国电机工程学会环境保护专业委员会火电厂水环境保护分专业委员会主持的“火电厂废水综合治理”学术交流会于1995年10月6日～8日在苏州召开，来自全国科研所、设计院、火电厂、大专院校和电管局等单位的44名代表出席了会议，其中水环境分专业委员会委员14人。本次研讨会共收到论文34篇，经有关委员及专家评审，选出其中23篇论文汇编成论文集出版。16位代表在研讨会上宣读了论文，论文主要内容包括了以下几个方面：1．当前火电厂废水排放状况及近期控制目标及对策；2．火电厂水平衡优化研究；3．灰水结垢倾向判断及回收L艺研究；4．火电厂…     

火电厂节水与废污水回用研究

从火电厂加强水务管理和废污水治理的角度，对生活污水、含油污水、灰水、循环水的治理现状和措施作了较全面地介绍，初步分折了火电厂节水的经济效益，并介绍了实际工程设计中的一些体会。     

浙江省火电厂烟气连续监测系统运行现状及运管方式

介绍了火电厂烟气连续监测系统(CEMS)的类型及系统组成，分析了浙江省火电厂已安装CEMS的现状和存在问题，对系统的运行管理方式进行了探讨，并提出建议。     

火电厂水环境与pE的联系

火电厂水环境是较为复杂的体系,其组成不仅涉及废水中的各种反应,也关系到水和环境的其它部分(气、液、悬浮物、沉积物等)相互转化及迁移的过程。火电厂水体系与pE值(即体系平衡时的电子活度)有密切联系。深入研究火电厂周围水环境以及有关供水、废水处理、排放水质的pE值,对水污染防治工作有重要意义。     

50 MW机组水膜除尘器改造工程实践

从某火电厂50MW机组锅炉烟气除尘系统存在的缺陷入手，详细介绍了将原文丘里水膜除尘系统改造为EE型电除尘系统的工程实例，旨在为同类机组除尘系统的改造提供借鉴，以满足日益严格的环境标准要求。     

马头电厂废水处理系统介绍

介绍了河北马头电厂废水处理工艺系统流程、设计及系统调试运行指标。处理后的电厂废水作为循环冷却水的补水,减少了新鲜水用量和污水排放量，对北方地区厂区废水回收利用具有借鉴意义，在火电厂废水资源利用方面有很好的应用前景。     

灰水回收用于循环冷却水技术可行性研究

将火电厂冲灰水回水回收至冷却水母管，用作循环冷却水的补充水之灰水再利用方案尚属首创。小型模拟台等多项试验证明：该方案在技术上是可行的，灰水回收后不会增加冷却水系统和冲灰系统的结垢或腐蚀，且有较显著的经济效益。     

灰水回收用于循环冷却技术可行性研究

将火电厂冲灰水回水回收至冷却水母管，用作循环冷却水的补充水之灰水再利用方案尚属首创，小型模拟台等多项试验证明：该方案在技术上是可行的，灰水回收后不会增中冷却水系统和冲灰系统的结垢或腐蚀，且有较显著的经济效益。     

火电厂节水降耗措施

火电厂是耗水大户,随着水资源的日渐匮乏及环保法律的日趋严格,合理利用水资源,已成为火电厂面临的紧迫任务.在对国内用水指标进行分析的基础上,提出改造火电厂循环冷却水系统和除灰渣系统、建立废水回收利用系统、完善水务管理等节水措施,为火电厂的节水降耗和安全经济运行提供理论指导.     

Distribution of Cd,Ck, Pb and Zn in Soil and Vegetation Compartments in Stands of Five Boreal Tree Species in N.E. Sweden

Concentrations and total quantity of cadmium (Cd), cupper (Cu),lead (Pb) and zink (Zn) were determined in biomass and soil compartments in a replicated tree species experiment with 27-yr-old stands growing on former farmland in N.E. Sweden. Sequentialextractions of soil samples were performed in order to estimate the exchangeable and an organically bound fraction of each element. The tree species included were Picea abies (L.)H. Karst., Pinus sylvestris L., Pinus contorta Dougl., Larix sibirica Ledeb., and Betula pendula Roth.Tree species influenced the rate of removal of Cu, Pb and Zn incase of stemwood harvesting, and of Cd, Cu and Zn in the case ofwhole-tree harvesting. B. pendula and P. abies had higher quantities and average concentrations of Zn in the biomass. For all species, >50% of the Zn in the stems was found in the bark. P. abies and L. sibirica had higher quantities of Cu in the biomass than the other species.P. abies and P. contorta had high quantities of Cd inthe biomass in relation to the other species. Branches and stembark contained high concentrations of Cd and Pb in relation to foliage and stemwood. Dead branches had especially high concentrations of Pb. The high accumulation rate of Zn in thebiomass of B. pendula was related to a low exchangeable amount of Zn in the A horizon. In the superficial centimeters ofthe A horizon, a depletion similar to that found for Zn was detected for Cu, whereas for Cd and Pb, no correlations were found between quantities of elements in the trees and element pools in the soil.     

Programs assessing implementation and effectiveness of state forest practice rules and BMPs in the West

The major forest nonpoint source control programs in the West are largely regulatory, either under forest practices acts (California, Idaho, New Mexico, Nevada, Oregon, and Washington) or a streamside management act (Montana). These programs and the specific rules they enforce continue to undergo intensive scrutiny. Still, the questions are the same for these regulatory programs as for states that base nonpoint source control on voluntary BMPs (Arizona, Colorado, Utah, Wyoming). Are the rules or BMPs being applied, and are they effective in reducing nonpoint source pollution to levels that protect beneficial uses of water? The level of debate about forestry in the West has resulted in detailed monitoring and research to answer these questions. In the past, state agencies have assumed levels of BMP compliance based on the percent of operations without enforcement actions. These estimates are being replaced by statistically valid and reproducible monitoring of forest practices rules and BMP compliance levels. BMP effectiveness is being assessed using both qualitative and quantitative methods. This can involve field assessments, process-based research, and control watershed studies. Some trend monitoring is also beginning. With the regional implementation rate for forestry BMPs at about 94% and rising, it is likely that effectiveness testing will continue to be a priority and consume the majority of assessment resources for this region.     

Hysteresis in Reversal of Central European Mountain Lakes from Atmospheric Acidification

Extremely high emissions of S and N compounds in Central Europe (both 280 mmol m^-2 yr^-1) declined by 70and 35%, respectively, during the last decade. Decreaseddeposition rates of SO₄ ^-2, NO₃ ^-, and NH₄ ⁺ in the region paralleled emission declines. The reduction in atmospheric inputs of S and N to mountain ecosystemshas resulted in a pronounced reversal of acidification in the Tatra Mountains and Bohemian Forest lakes. Between the 1987–1990and 1997–1999 periods, concentrations of SO₄ ^-2 and NO₃ ^- decreased (average ± standard deviation) by 22±7 and 12±7 mol L^-1, respectively, in theTatra Mountains, and by 19±7 and 15±10 mol L^-1, respectively, in the Bohemian Forest. Their decrease was compensated in part (1) by a decrease in Ca²⁺ + Mg²⁺ (17±7 mol L^-1) and H⁺ (4±6 mol L^-1), and an increase in HCO₃ ^-(10±10 mol L^-1) in the Tatra Mountains lakes, and (2) by a decrease in Al (7±4 mol L^-1), Ca²⁺ + Mg²⁺ (9±6 mol L^-1), and H⁺ (6±5 mol L^-1), in Bohemian Forest lakes. Despite the rapid decline in lake water concentrations of SO₄ ^-2 and NO₃ ^- in response to reduced S and N emissions, their present concentrations in some lakes are higher than predictionsbased on observed concentrations at comparable emission rates during development of acidification. This hysteresis in chemical reversal from acidification has delayed biological recovery of the lakes. The only unequivocal sign of biological recovery hasbeen observed in erné Lake (Bohemian Forest) where a cladoceran species Ceriodaphnia quadrangular has recentlyreached its pre-acidification abundance.     

Reconstruction of Long-Term Changes in Lake water Chemistry,Zooplankton and Benthos of a Small,Acidified High-Mountain Lake: Magic Modelling and Palaeolimnogical Analysis

Starolesnianske pleso is a small and shallow acid lake in the High Tatra Mountains, situated at 2000 m above sea level, on granitic bedrock, with sparse and thin soil cover. When detailed measurements began in the 1980s Starolesnianske pleso had pH below 5 and only one species of cladoceran zooplankton, the ubiquitous Chydorus sphaericusPalaeolimnological investigations show changes in cladoceran zooplankton and chironomid zoobenthic assemblages since about 1920 and a major change in 1970–1980. The dynamic acidification model MAGIC was used to reconstruct changes in water chemistry over the past 150 years. The results from MAGIC agree well with the sediment record; pH levels gradually decreased from 6.5 in the mid-1800s to about 5.6 in 1920 (first response in biota) to below 5.0 by 1970, and concentrations of inorganic aluminium rose dramatically beginning about 1960. In the 1990s the lake water chemistry showed clear signs of reversal in acidification brought about by a major decline in S deposition.     

Heavy Metals Removal by Biosorption and Flotation

The removal of a mixture of heavy (toxic) metal cations (copper, nickeland zinc) from liquid effluents was investigated in this study at pilotscale, using counter-current contact mode. The innovative processinvolved the abstraction of metal ions onto fungal biosorbents, followedby the application of flotation for the subsequent solid/liquid separationof biomass particles. The ability of microorganisms to remove metal ionsfrom aqueous solutions is a well-known phenomenon. Nevertheless,engineering considerations are very important in decisions, concerningthe commercial future of biosorption and practical solutions are neededfor certain problems, such as the efficient post-separation ofmetal-loaded biomass. The two processes (flotation and biosorption) caneffectively operate in combination, in what it was termed biosorptiveflotation process. The sorbents may be recycled, after appropriate elutionof metals, as well as the treated (clean) water.     

Starch-plastic materials—Preparation,physical properties,and biodegradability (a review of recent USDA research)

Recent starch-plastic research at the National Center for Agricultural Utilization Research is reviewed and related worldwide efforts are noted. Properties of starch that influence its formulation and performance in plastics are discussed. Methods are given for preparation of starch-poly(methyl acrylate) graft copolymer, starch-poly(ethylene-co-acrylic acid), and starch-poly(ethylene-co-acrylic acid)-polyethylene plastics. Their physical properties are discussed, as is degradability by enzymes or amylolytic organisms from soil, ponds, and streams.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

High Immobilization of NH4+ in Danish Heath Soil Related to Succession,Soil and Nutrients: Implications for Critical Loads of N

During recent decades heathlands havechanged into grasslands in regions with high atmosphericnitrogen deposition. In regions with intermediatedeposition level (e.g., Denmark) changes have been lesspronounced which may be due to delay or decrease inresponse of the ecosystem. The mor layer (O horizon) mayplay an important role for this delay due to high sinkstrength for N. In this study, the capacity for netNH₄ ⁺ immobilization and mineralization wasstudied during short- and long-term incubations (2–36 days)of mor samples from Danish dry inland heaths. High short-term capacity for net NH₄ ⁺ immobilization wasfound to be a general characteristic of Danish heath morlayers both under heather (Calluna vulgaris) andcrowberry (Empetrum nigrum ssp nigrum), the latterdominating late stages in heathland succession. The netNH₄ ⁺ immobilization was higher under youngcompared to old or dead vegetation, and higher on lessnutrient poor soils than on extremely nutrient poor soils.The addition of N, P and C stimulated CO₂ productionand net NH₄ ⁺ immobilization, but not net Nmineralization. The immobilization of ¹⁵NH₄ ⁺caused release of dissolved organic N, increased N anddecreased C/N ratio in the microbial biomass, and indicatedgrowth of microorganisms with other metabolic abilitiesthan the indigenous population. No evidence was obtained ofstabilization of immobilized ¹⁵NH₄ ⁺ intosoil organic matter during the experiment. On background ofthe results and current knowledge it was concluded that therecognition of the high capacity for net NH₄ ⁺immobilization in mor layers does not allow for a raiseof critical loads for N for northern dry inland heaths.     

Bioassessment of silvicultural impacts in streams and wetlands of the Eastern United States

Bioassessment is a useful tool to determine the impact of logging practices on the biological integrity of streams and wetlands. Measuring biota directly has an intuitive appeal for impact assessment, and biota can be superior indicators to physical or chemical characteristics because they can reflect cumulative impacts over time. Logging can affect stream and wetland biota by increasing sedimentation rates, altering hydrologic, thermal, and chemical regimes, and changing the base of food webs. Biotic impacts of logging on streams compared to wetlands probably differ, and in this paper we review some of those differences. In streams, invertebrates, fishes, amphibians, algae, and macrophytes have been used as indicators of logging impacts. In wetlands, bioassessment is just beginning to be used, and plants and birds are the most promising indicator taxa. Various best management practices (BMPs) have been developed to reduce the impacts of logging on stream and wetland biota, and we review quantitative studies that have evaluated the efficacy of some of these techniques in streams and wetlands in the eastern United States. Remarkably few studies that address the overall efficacy of BMPs in limiting biotic changes in streams and wetlands after BMP implementation have been published in scientific journals, although some work exists in reports or is unpublished. We review these works, and compile conclusions about BMP efficacy for biota from this body of research.     

Characterization of air emissions and residual ash from open burning of electronic wastes during simulated rudimentary recycling operations

Air emissions and residual ash samples were collected and analyzed during experiments of open, uncontrolled combustion of electronic waste (e-waste), simulating practices associated with rudimentary e-waste recycling operations. Circuit boards and insulated wires were handled separately to simulate processes associated with metal recovery. The average emissions of polychlorinated dibenzodioxins and dibenzofurans (PCDD/PCDFs) were 92 ng toxic equivalency (TEQ)/kg [n = 2, relative standard deviation (RSD) = 98%] and 11 900 ng TEQ/kg (n = 3, RSD = 50%) of the initial mass of the circuit boards and insulated wire, respectively. The value for the insulated wire is about 100 times higher than that for backyard barrel burning of domestic waste. The emission concentrations of polybrominated dibenzodioxins and dibenzofurans (PBDD/PBDFs) from the combustion of circuit boards were 100 times higher than for their polychlorinated counterparts. Particulate matter (PM) sampling of the fly ash emissions indicated PM emission factors of approximately 15 and 17 g/kg of the initial mass for the circuit boards and insulated wire, respectively. Fly ash samples from both types of e-waste contained considerable amounts of several metallic elements and halogens; lead concentrations were more than 200 times the United States regulatory limits for municipal waste combustors and 20 times those for secondary lead smelters. Leaching tests of the residual bottom ash showed that lead concentrations exceeded U.S. Environmental Protection Agency landfill limits, designating this ash as a hazardous waste.     

Selection of Autochthonous Plant Species from SE Spain for Soil Lead Phytoremediation Purposes

Mining activity in SE of Spain, in the west Mediterranean coast, originated more than two millenniums ago. It has generated huge areas affected by heavy metals contamination, especially of lead, which is possibly one of the most important. Investigations related to the selection of autochthonous plant taxa from a typical Spanish Mediterranean area, useful for phytoextraction and phytostabilization purposes in these polluted areas are shown. Under these edaphoclimatic conditions 12 interesting species were considered, from them six taxa were chosen for further studies. Some plant species have been proposed either for phytoextraction or phytostabilization purposes. Recommendations for further research have been discussed.