超声辐射法降解废水中的二甲苯、苯酚和丙烯腈

采用频率为20kHz的超声波处理二甲苯、丙稀腈、苯酚溶液。实验结果表明，在二甲苯初始质量浓度为27．6mg／L、H2O2质量浓度为1．68g／L、溶液温度为25℃、声强为141．32W／cm^2、辐射全程时间为60min的条件下，二甲苯降解率可达99．20％；在丙烯腈初始质量浓度为100．0mg／L、通氧量为15mL／rain、溶液温度为28℃、声强为141．32W／cm^2、辐射全程时间为30rain的条件下，丙烯腈降解率可达98．20％；在苯酚初始质量浓度为20．0mg／L、H202质量浓度为1．50g／L、FeSO4质量浓度为0．22g／L、溶液温度为28℃、声强为48．92W／cm^2、辐射全程时间为40rain的条件下，苯酚降解率可达99．81％。     

Ti/MnO2/PbO2电极的制备及电催化降解罗丹明B

采用电沉积法制备了Ti／MnO2／PbO2电极，并用其对质量浓度为20mg／L的罗丹明B模拟废水进行了电催化降解实验。实验结果表明：原水pH为4．95，无须调节废水的pH；最佳电解实验条件为：支持电解质NazSO4浓度0．09mol／L，电解电流密度40mA／cm^2，处理时间40min，在此条件下罗丹明B的去除率接近100％。     

改进铁氧体共沉淀法去除污泥浸出液中的铜锌

采用改进铁氧体共沉淀法，用石灰乳溶液作中和剂，从污泥浸出液中去除铜、锌。实验结果表明，在混合液．pH为8．9、反应温度为室温、反应时间为1h、FeCl3和FeSO4初始浓度分别为0．1068mol／L和0．0534mol／L、n（Fe^3＋）：[n（Cu^2＋）＋n（Zn^2＋）]=10的最佳工艺条件下，浸出液中铜去除率为94．5％，锌去除率为98．0％。     

三维电极法处理氯苯废水

采用三维电极法处理氯苯废水。研究了外加槽电流、停留时间、氯苯初始质量浓度、废水初始pH等对氯苯去除率的影响。实验结果表明：外加槽电流增大，氯苯去除率明显提高；停留时间延长，氯苯去除率提高；而废水初始pH和氯苯初始质量浓度的变化对氯苯去除率影响不大。在外加槽电流为2．0A、氯苯初始质量浓度为1～200mg／L、停留时间为40～60min、废水初始pH为7的条件下，氯苯去除率达83％以上。并探讨了氯苯的电化学降解机理。     

污泥活性炭的制备及其对溶液中Cr6+的吸附

以城市污水厂剩余污泥为原料，采用ZnCl2作活化剂，热解制备污泥活性炭。实验结果表明，制备污泥活性炭的最佳条件热解温度为550℃，ZnCl2溶液浓度为3mol／L，ZnCl2溶液体积与污泥质量比（mL／g）为2．5：1，热解时间为25min。用所制备的污泥活性炭吸附溶液中的Cr6＋最佳吸附条件为：吸附时间90min，Cr6＋初始质量浓度50mg／L，污泥活性炭加入量0．2g，溶液pH2，在此条件下，Cr6＋去除率达99．9％。污泥活性炭对溶液中Cr6＋的吸附等温线属于I型，等温吸附方程可用Langmuir模型和Freundlich模型来拟合。     

聚合氯化铝锌絮凝剂的制备及其性能

用在AlCl，与ZnCl2溶液中加NaOH溶液的方法制备无机高分子絮凝剂聚合氯化铝锌（PAZC），通过正交实验确定的最佳制备条件为：反应时间10min、碱化度2．2、氯化铝浓度0．5mol／L、NaOH溶液浓度0．5mol／L。在n（Zn）：n（Al）=0．6、水样pH=7．8、PAZC加入量为5mg／L的条件下，浊度和COD去除率分别为98．9％和88．2％。PAZC与聚合氯化铝对各种工业废水的处理效果比较结果表明，PAZC对各种工业废水的处理效果较好。从废水处理成本来看，PAZC具有较好的经济效益。     

Fenton试剂降解选矿废水中残余黄药

采用Fenton试剂处理选矿废水中残余的黄药,分别考察了氧化时间、反应初始pH、Fe^2 浓度及H2O2用量对黄药降解效果的影响;用正交实验确定了4个因素的最佳条件。结果表明,反应初始pH和H2O2用量是影响黄药去除效果的主要因素。氧化时间为60min、反应初始pH为4、Fe^2 质量浓度为20mg／L、H2O2质量浓度为20mg／L、黄药质量浓度为：125mg/L时,黄药的去除率达到99．5％,COD去除率为87．5％。     

UV/Fenton氧化-混凝联合工艺处理含酚废水

采用UV／Fenton氧化-混凝联合工艺对模拟苯酚废水进行处理,探讨了UV／Fenton预氧化程度和混凝处理条件对模拟苯酚废水处理效果的影响。结果表明,采用混凝处理,COD去除率仅为14．1％;当UV／Fenton预氧化处理过程中H2O2的质量浓度为150～300mg／L时,废水的混凝性能可提高1．5倍以上;当H2O2质量浓度为450mg／L、光反应时间为30min时,采用UV／Fenton氧化一混凝工艺联合处理后COD去除率达82．7％。苯酚废水采用UV／Fenton预氧化处理后,进行混凝处理过程的适宜pH为6．5,混凝剂Fe^3 的适宜质量浓度为500mg／L.     

活性艳蓝KN-R染料废水的电解氧化及其毒性削减

以Ti／RuO-IrO2为阳极、不锈钢板为阴极，采用电解法处理活性艳蓝KN—R染料废水（简称染料废水）。研究了电解过程中主要因素对染料废水色度去除率的影响，并对处理后废水的生物毒性和可生物降解特性进行了评估。结果表明：在pH为8、NaCl溶液浓度为0．050mol／L、电流密度为10．42mA／cm2、极板距离为3cm的条件下，电解15min染料废水色度去除率达100％；电解120min后，水样的发光细菌相对发光度提高至60．88％，活性污泥耗氧速率常数较原水提高了103％，说明染料废水的毒性得到了有效削减，可生化性得到明显改善。     

钯离子液相催化氧化低浓度磷化氢

采用Pd^2＋液相催化氧化低浓度PH3，考察了Pd^2＋浓度、O2体积分数、PH3质量浓度、混合气流量、反应温度等因素对Pd^2＋吸收液去除低浓度PH3效果的影响。实验结果表明，采用10mL Pd^2＋浓度为0．112mol／L的水溶液作为吸收液净化含低浓度PH3的混合气，在反应温度22℃、O2体积分数5％、PH3质量浓度850mg／m^3、混合气流量190mL／min的条件下，印min之内PH3去除率保持在90％以上。Pd^2＋浓度越高、O2体积分数越大、反应温度越高，PH3去除率越高；混合气流量越大，PH3去除率越低；反应温度越低、O2体积分数越大，PH3去除率的下降速率越小。     

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.     

四氮唑废水处理工艺设计

高浓度、高盐分的四氮唑生产废水通过三效蒸发浓缩，馏出液经铁炭氧微电解和混凝预处理，再采用水解酸化一接触氧化一反应二沉主体组合工艺进行处理。研究了该工艺所需构筑物和设备的设计与选型。该工艺在正常运行条件下，处理后出水pH6～9，COD 302mg／L，BOD5 108mg／L，SS30mg／L，色度36倍，水质达到GB8978--1996（污水综合排放标准》三级标准。     

Application of Cellulose Microfibrils in Polymer Nanocomposites

Cellulose microfibrils obtained by the acid hydrolysis of cellulose fibers were added at low concentrations (2–10% w/w) to polymer gels and films as reinforcing agents. Significant changes in mechanical properties, especially maximum load and tensile strength, were obtained for fibrils derived from several cellulosic sources, including cotton, softwood, and bacterial cellulose. For extruded starch plastics, the addition of cotton-derived microfibrils at 10.3% (w/w) concentration increased Young’s modulus by 5-fold relative to a control sample with no cellulose reinforcement. Preliminary data suggests that shear alignment significantly improves tensile strength. Addition of microfibrils does not always change mechanical properties in a predictable direction. Whereas tensile strength and modulus were shown to increase during addition of microfibrils to an extruded starch thermoplastic and a cast latex film, these parameters decreased when microfibrils were added to a starch–pectin blend, implying that complex interactions are involved in the application of these reinforcing agents.     

Does Soil Acidification Affect Spruce Needle Chemical Composition and Tree Growth?

In 1994, a large survey of soil chemistry was undertaken in thecounty of Värmland in central Sweden (Lundström et al., 1998).The southern part of the county was affected by soilacidification whereas there were no such indications in thenorthern part. To investigate the influence of soil chemistryon the trees at the specific sites, the survey was continued byan analysis of needle chemistry (Norway spruce) which wasundertaken at 150 of the 180 sites, and of tree growth at 65 ofthe 180 sites. Growth was expressed as a ratio between expectedgrowth, estimated with a national, empirical growth model, andthe growth observed in the field. In statistical analyses,using rank correlation, PCA and PLS, there were only weakindications of an influence of soil chemistry on needlechemistry and on tree growth. A moderate correlation betweennitrogen and sulphur in needles was found, which wasinterpreted as an effect of deposition and of processes in thetree canopy. No obvious regional pattern of the growth ratiowas found, in contrast to the clear pattern of soilacidification. The statistical analysis could not with anycertainty point out any of the soil chemistry variables asespecially important for the tree growth ratio.     

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.