Fenton试剂氧化—石灰法处理苎麻脱胶废水

采用Fenton试剂氧化一石灰法处理苎麻脱胶废水（简称废水）。在pH为8．3的废水中FeSO4·7H2O、H2O2、饱和石灰乳的加入量分别为1．5g／L、1．0mL／L和1．0mL／L的条件下对废水进行处理，废水COD由650mg／L降至200mg／L以下，COD去除率约为70％；色度由500倍降至70倍以下，色度去除率约为90％，出水COD和色度均达到GB8978-1996（污水综合排放标准）中的二级排放标准。     

生物絮凝剂MBFGA1预处理乳制品加工废水

用生物絮凝剂MBFGA1预处理乳制品加工废水（简称废水）。实验结果表明，废水处理的水力条件为：以150r／min的转速搅拌30S，再以30r／min的转速搅拌20min；MBFGA1的最佳加入量为15mg／L；废水pH为4．0时，MBFGA1对废水的絮凝处理效果最好；废水温度对浊度、COD去除率有一定的影响，在20～45℃时，废水浊度的去除率始终保持在85％以上；30℃时，COD去除率达到最大值65．0％。     

絮凝沉淀-Fenton试剂氧化法处理含高浓度硫酸盐的洗涤剂生产废水

采用絮凝沉淀-Fenton试剂氧化法处理含高浓度硫酸盐的洗涤剂生产废水（简称废水），考察了各种因素对COD去除率的影响。实验结果表明：根据实际废水的水质情况，选用聚合氯化铝（PAC）为絮凝剂，PAC最佳加入量为0．3g／L，经絮凝处理后COD去除率为42．3％；Fenton试剂氧化的最佳操作条件为：n（H2O2）：n（Fe^2＋）=0．5、H2O2加入量为7mmol／L、反应时间为2h，不调节废水初始pH，经Fenton试剂氧化处理后COD去除率为70％以上。经絮凝沉淀-Fenton试剂氧化法处理后，废水COD由1950mg／L降至240mg／L，总的COD去除率为87．7％，废水处理效果良好。     

活性炭/H2O2催化氧化-絮凝法预处理化工有机废水

用活性炭作催化剂、H2O2作氧化剂催化氧化预处理高浓度化工有机废水，考察了各种因素对COD去除率的影响。实验结果表明，在H2O2加入量为0．8mL／L、活性炭与H2O2质量比为0．7、废水pH为4的条件下，反应120min后，调废水pH至8，加入絮凝剂聚合氯化铝进行絮凝沉淀，废水COD去除率达70％以上，色度去除率达80％以上。通过色谱-质谱仪对处理前后废水中的有机物进行分析，初步探讨了活性炭／H2O2催化氧化-絮凝法预处理化工有机废水的作用机理。     

混凝—催化氧化法处理丁苯橡胶生产废水

以聚合氯化铝（PAC）、阴离子聚丙烯酰胺（PAM）为混凝剂，以H2O2-O3为氧化剂，采用混凝-催化氧化法处理对丁苯橡胶生产废水。考察了混凝剂种类及其加入量、废水pH对混凝处理效果的影响，氧化剂及其加入量、反应时间和废水pH对COD去除率的影响。实验得出的最佳工艺条件：混凝实验，废水pH为7、PAC和PAM加入量为400mg／L和4mg／L；催化氧化实验，废水pH为7～8、H2O2加入量为200mg／L、H2O2与O3的质量比为0．5。处理后，废水COD从860mg／L降至145mg／L，COD去除率达83．1％，出水水质达到国家二级排放标准。     

超声波-H2O2协同作用处理孔雀绿废水

采用超声波（US）-H2O2协同作用处理含孔雀绿的废水（简称废水）；考察了H2O2加入量、US功率、反应温度、反应时间对废水色度、COD去除率的影响，并对US-H2O2体系降解孔雀绿的机理进行了探讨。实验结果表明：在US作用下，H2O2加入量对废水色度、COD去除率的影响较大；废水色度、COD去除率均随US功率和反应时问的增加而提高；在US～H2O2体系中，低温对处理废水有利，高温反而不利；US—H2O2处理废水具有协同作用。在废水量为100mL、pH为7．3、反应温度为40℃、H2O2加入量为10mL、US功率为240W、反应时间60min的条件下对废水进行处理，废水COD、色度去除率分别为97．5％，98．8％。     

双氰胺-甲醛聚合物-聚合氯化铝复合絮凝剂的合成及应用

以双氰胺、甲醛、氯化铝为主要原料，加入添加剂合成了双氰胺-甲醛聚合物（DF）-聚合氯化铝（PAC）复合絮凝剂。采用模拟印染废水考察了各种因素对DF—PAC复合絮凝剂混凝脱色性能的影响。实验结果表明，在双氰胺、甲醛、氯化铝、添加剂加入量分别为29．1，57．8，4．8，12．5g，反应温度（70±1）℃、反应时间2．5h的条件下制得的DF—PAC复合絮凝剂的絮凝脱色性能良好，COD去除率不小于90％，色度去除率不小于99％。与PAC和DF絮凝剂相比，DF—PAC复合絮凝剂对实际印染废水的絮凝脱色效果更好。     

全白土催化剂生产废水的处理

用4种无机絮凝剂和3种有机絮凝剂进行了脱除全白土催化剂生产废水（简称废水）中固体悬浮物（SS）的实验研究。实验结果表明：在废水pH6．8条件下，无机絮凝剂和有机絮凝剂脱除废水中SS的效果均较差，用无机絮凝剂时的SS去除率低于26％，用有机絮凝剂时的SS去除率低于18％；废水pH对SS去除率的影响较大，当调节废水pH为8．0时，无机絮凝剂中硫酸铝脱除废水中的SS效果最好，在硫酸铝加入量为0．02mg／L、沉降时间为2h的最佳操作条件下，SS的去除率可达93％。     

新型聚硅氯化铁铝絮凝剂的制备及性能

以二甲基二氯硅烷为硅源，与氯化铁、氯化铝聚合制得新型的聚硅氯化铁铝（PSFAC）絮凝剂，考察了制备条件及PSFAC对含油废水和药厂废水的絮凝效果。制备PSFAC的最佳条件：nFc：nAl为0．4,nSi：n（Al＋Fe）为0．1，碱化度为2．0，C（Al,Fe）、为0．1mol／L，熟化时间为1-2d。当PSFAC加入量为10mg／L时，对含油废水、药厂废水的浊度去除率分别为84％和86％。PSFAC具有加入量少、沉降速度快、适用的pH范围较宽等优点。     

聚合硅酸氯化铝铁的制备及其絮凝性能

利用盐酸酸洗废液制备聚合硅酸氯化铝铁（PSAFC），并用PSAFC处理造纸脱墨废水，考察了各种因素对絮凝效果的影响。实验结果表明：在废水pH为6、PSAFC加入量为240mg／L、搅拌转速为150r／min、搅拌时间为2min，静置时间为25min的条件下，COD、浊度、色度的去除率分别为87．2％，99．2％，94．5％；PSAFC的絮凝效果明显好于市售的聚合氯化铝和聚合氯化铁.     

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.     

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.     

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.     

Concentrations and Pools of Heavy Metals in Urban Soils in Stockholm,Sweden

The concentrations of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb andZn) and arsenic (As) were surveyed and the metal pools estimatedin soils in Stockholm Municipality. The sampling sites were distributed all over the entire municipality with a higher sampling density in the city centre. Soils were sampled to a maximum depth of 25 to 60 cm. Soil texture, total-C content, electrical conductivity and pH were analysed. Heavy metal concentrations were determined after wet digestion with boiling7 M HNO₃.The results showed a wide range in heavy metal concentrations, as well as in other soil properties. The city centre soils constituted a rather homogeneous group whereas outside this areano geographical zones could be distinguished. These soils were grouped based on present land use, i.e. undisturbed soils, public parks, wasteland (mainly former industrial areas), and roadside soils. The city centre and wasteland soils generally hadenhanced heavy metal concentrations to at least 30 cm depth compared to park soils outside the city centre and rural (arable)soils in the region, which were used to estimate background levels. For example, the mean Hg concentration was 0.9 (max 3.3)mg kg^-1 soil at 0–5 cm and 1.0 (max 2.9) at 30 cm depth in the city centre soils, while the background level was 0,04 mg kg^-1. Corresponding values for Pb were 104 (max 444) and135 (max 339) mg kg^-1, at 0–5 and 30 cm, respectively, while the background level was 17 mg kg^-1.The average soil pools (0–30 cm depth) of Cu, Pb and Zn were 21,38 and 58 g m^-2 respectively, which for Pb was 3–4 timeshigher and for Cu and Zn 1.5–2 times higher than the backgroundlevel. The total amount of accumulated metals (down to 30 cm)in the city centre soils (4.5^*10 ⁶ m² public gardens and green areas) was estimated at 80, 1.1, 120 and 40 t for Cu, Hg, Pb and Zn, respectively. The study showed (1) thatfrom a metal contamination point of view, more homogeneous soilgroups were obtained based on present land use than on geographicdistance to the city centre, (2) the importance of establishing a background level in order to quantify the degree of contamination, and (3) soil samples has to be taken below the surface layer (and deeper than 30 cm) in order to quantify theaccumulated metal pools in urban soils.