微电解法预处理对氟硝基苯废水的研究

采用废铁屑微电解法对氟硝基苯废水进行预处理，在铁粉投加量为3.0g/L、phH为3．0、反应时间为3h、催化剂氯化铵用量为2.0g/L的条件下，对氟硝基苯转化为氨基氟苯的转化率为70％、出水的BOD5／COD值由0上升到0．27。     

混凝-催化氧化法预处理氨基C酸生产废水

采用混凝-催化氧化组合工艺预处理氨基C酸生产废水，考察了混凝剂加入量、废水pH、氧化剂加入量、反应时间和催化剂的重复使用次数等因素对废水处理效果的影响。混凝-催化氧化法预处理氨基C酸生产废水的最佳工艺条件为：质量分数为10％的FeSO4溶液作混凝剂，加入量为250InL／L；质量分数为1％的ClO2溶液作氧化剂，加入量为75mL／L；Ni／AC作催化剂，加入量为40g/L；废水pH为3．2；催化氧化反应时间为60min。在该条件下，废水的COD去除率可达78．4％，BOD，／COD由原来的0．076提高到0．292，可生化性得到明显改善。Ni／AC催化剂连续使用7次后仍保持稳定的催化活性。经济性初步分析表明，1t废水的处理成本约为16元。     

已二酸生产副产物——混合二元酸的综合利用

采用一水合硫酸氢钠作为催化剂，催化己二酸生产副产物——混合二元酸与甲醇反应合成混合二元酸二甲酯。优化工艺条件为：混合二元酸加入量0．1mol，无水甲醇加入量0．5mol，一水合硫酸氢钠加入量4．0g，环己烷加入量20mL，反应时间1．5h。合成混合二元酸二甲酯的酯化反应收率大于97％。经气相色谱检测，产物中酯的质量分数为98．91％。一水合硫酸氢钠可重复使用3次。     

铜铬催化剂清洁生产工艺研究

采用清洁生产概念与思维模式,对铜铬催化剂生产全过程进行审核,找出造成其产率低、活性差、污染重的原因及影响因素。以新催化剂研制理论和方法为指导,探讨铜铬催化剂用于糠醇生产过程中提高其产率、活性、原材料利用率以及减轻污染的清洁生产工艺。试验结果表明,在pH为6．2～6．5、Cu／Cr质量比为1：1、反应温度为65℃,活化温度为400℃的条件下,催化剂能获得较高产率和活性。按此新工艺生产的催化剂,产率可提高22％,Cr^6 的排放量可减少95％,活性可提高一倍,废品率可由原来的10％降至零。     

氨基苯甲醚生产废水的综合利用

氨基苯甲醚是染料、香料、医药和食品工业的重要原料。工业上以硝基氯苯为原料 ,经甲醇、氢氧化钠甲氧基化后 ,用质量分数 6 0 %的结晶硫化钠还原而得。由于采用大量的硫化钠作还原剂 ,因此在排出的工业废水中含有较高浓度的硫代硫酸钠、氢氧化钠、硫化钠和少量的氨基化合物。废水 COD较高 ,毒性较大 ,直接排放将严重污染环境。我们以吉化染料厂氨基甲醚车间排出的废水为原料 ,经聚砜复膜超滤除去有机物及杂质 ,通过真空浓缩得到亚硫酸钠质量分数不少于 40 %的碱混合物 ,并应用于造纸行业 ,解决了氨基苯甲醚生产废水的污染问题。1　废水组…     

环保型脲醛树脂胶粘剂的合成研究

介绍了聚乙烯醇(PVA)、三聚氰胺在脲醛树脂胶粘剂合成过程中所起的改性作用,研究了反应温度、反应体系pH、甲醛与尿素摩尔比、PVA和三聚氰胺用量对脲醛树脂胶粘剂性能的影响。试验结果表明,在反应温度为80℃、反应体系pH为5．0、甲醛与尿素摩尔比为1．5、PVA和三聚氰胺用量分别为尿素与甲醛溶液总质量的1．0％和5％的条件下,合成的脲醛树脂胶粘剂的剪切强度为2．99MPa,游离甲醛的质量分数由传统工艺生产产品的0．6％～0．8％降低至0．063％,耐沸水时间为108min,且贮存稳定性好,达到了HJBZ-1998国家环境标志产品技术要求。     

废甲醇催化剂的回收和利用

介绍了利用废甲醇催化剂生产活性氧化锌和五水硫酸铜的方法，试验结果表明，最佳工艺条件为：催化剂粒度80目；酸浸反应的硫酸浓度3．6则mol/L，100g原料中硫酸用量325mL；净化反应的pH控制在5—5．5，温度85℃；活性氧化锌煅烧温度800℃；铜粉焙烧温度600℃，通风量0．8L／min，焙烧时间2．5h；硫酸铜生产过程中，反应温度为60—80℃，时间2h。该方法具有工艺简单、操作方便、产品质量好的特点，并可减少环境污染，变废为宝，具有较好的经济效益。     

采用絮状锰悬浊液催化剂空气氧化处理含硫废水

探讨了一种快速降解含硫废水中硫化物的新方法。用可溶性二价锰盐在pH为10．5－12．0时曝气,制得絮状锰悬浊液催化剂。使用该催化剂可将废水中S^2-的氧化反应速率大为提高,反应时间大为缩短,S^2-去除率几近100％;同时还可大大降低废水的COD,因此可大大降低生化处理系统的负荷。处理S^2-质量浓度为50－2000mg/L含硫废水的最佳工艺条件：絮状锰悬浊液催化剂与废水的体积比为0．8－1．0,pH为10－12,曝气量为50L/h左右,反应温度为15－45℃。絮状锰悬浊液催化剂可循环使用。     

干法腈纶废水处理技术

采用铁碳内电解-混凝沉淀预处理工艺处理干法腈纶废水。废水pH为4左右，经内电解反应2h，出水用聚合硫酸铁和阴离子型聚丙烯酰胺混凝沉淀1．5h后，废水的COD由1650mg／L降到1310mg／L，去除率为20．6％，BOD5／COD由原来的0．27提高到0．38。然后再采用水解酸化-好氧生化一生物硝化工艺处理预处理出水，最终出水COD为148mg／L，BOD，为16mg／L，氨氮质量浓度为13mg／L，SS质量浓度小于100mg／L，出水水质达到腈纶行业一级排放标准。     

铁屑流化床预处理-催化氧化-混凝沉淀组合工艺处理有机硅废水

采用铁屑流化床预处理、负载活性炭催化剂催化氧化和混凝沉淀组合工艺处理有机硅废水。废水经铁屑流化床预处理后Cu^2＋的去除率达99．90％，COD去除率达23．9％；负载活性炭催化剂催化氧化的最佳工艺条件：催化剂质量浓度为0．5g/L，H202质量浓度为2400mg/L，不投加FeSO4，反应时间为60min，体系pH为3-4，COD去除率达82％。催化氧化后的废水经混凝沉淀处理，调节pn为8-9，可达标排放。     

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.     

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.     

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.     

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.     

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.     

Urban Metal Flows – A Case Study of Stockholm. Review and Conclusions

Metals have rapidly accumulated in the anthroposphere, especiallyin urban areas, indicating possible environmental and resource problems. Here, Stockholm City was chosen for a case study of urban metal flows, i.e. metal inflow to, metals in the stock of,and metal outflow from the anthroposphere to the biosphere. Themetal stock of Stockholm is large and still growing. The large amounts of metals in the solid waste fraction totally dominatethe outflow from the city. For major parts of the stock, the emissions from goods in use are negligible. There are, however,goods applications corresponding to significant emissions: e.g. the traffic sector (Cu, Zn, Cr, Ni, Pb), the tapwater system (Cu), roofs/fronts or other metal surfaces (Cu, Zn). Today's known metal flows from the anthroposphere of Stockholm to the biosphere and sewage sludge are quantitatively dominated by Zn(34 ton y^-1) and Cu (14 ton y^-1). Historical and present emissions have resulted in high metal concentrations insediments (especially Cd, Hg and Pb, but also Cu and Zn), groundwater (Cu, Hg) and in soils (Hg, Cu, Pb). At present theannual median concentrations are below the Swedish limits for metals in sewage sludge, even if the safety margins aresmall for Cd, Hg and to some extent Cu. The flows of Cu and Zn to Stockholm soils are high with a significant accumulationindicating an environmental impact in a longer time perspective.High levels of metals in surface sediments in the waterenvironments reflects an ongoing input where these metals aretransported from known (Cu, Zn) and or partly unknown (Cd, Hg, Pb) sources. In future urban areas, monitoring of metal flows must be performed both in the anthroposphere and the biospherein order to have a pro active approach to urban environmentalproblems and to get prompt answers to measures taken.