Fenton氧化-生物接触氧化工艺处理甲醛和乌洛托品废水

采用Fenton氧化一生物接触氧化工艺处理含甲醛和乌洛托品的模拟废水（简称废水）,在H2O2（体积分数30％）加入量2．5g／L、H2O2与Fe^2＋质量浓度比3．75、反应时间3h、不调节废水初始pH的Fenton氧化预处理最佳操作条件下,废水COD从1000mg／L左右降至300mg／L,COD去除率达72％。原废水完全无法直接进行生化处理,经Fenton氧化预处理后其BOD,／COD约为0．5,易于生化处理。Fenton氧化一生物接触氧化工艺处理废水,生物接触氧化停留时间为12h时,废水COD去除率高达94％,处理后出水COD小于70mg／L,处理效果很好。     

微电解-催化氧化法处理高浓度甲醇废水

采用微电解一催化氧化法处理某化工厂的高浓度甲醇生产废水。实验结果表明：在进水pH为2．0、铁炭质量比为2、微电解时间为14h、空气流量为500mL／min的条件下,废水经微电解处理后,出水COD由原来的约7000mg/L降至约1000mg／L,COD去除率达85％以上;在过滤后微电解出水COD约为950mg／L、微电解出水pH为6．5、空气流量为300mL／min、催化氧化时间为3h时的条件下,经催化氧化处理后,出水COD降至100mg/L以下,出水水质达到GB8978--1996《污水综合排放标准》的二级标准。     

微电解—Fenton试剂氧化—A/O工艺处理制药废水

采用微电解—Fenton试剂氧化—A/O组合工艺处理高浓度制药废水。实验结果表明:经微电解—Fenton试剂氧化工艺预处理后,COD去除率可达50%~60%,BOD5/COD提高到0.3以上;预处理后的废水与清洗废水和生活污水混合,采用生化法进一步处理,出水COD小于100 mg/L,BOD5小于20 mg/L,ρ(NH3-N)小于50 mg/L,SS小于70 mg/L,满足GB 8978—1996《污水综合排放标准》中的三级排放标准。     

混凝-间歇式活性污泥法处理炼油废水

采用混凝-间歇式活性污泥（SBR）法处理炼油废水,考察了混凝、SBR法对炼油废水的处理效果。实验结果表明：在硫酸铝、聚丙烯酰胺、CaCl2加入量分别为50,3,100mg／L的条件下,油去除率为82．7％,COD去除率为57．1％,BOD,／COD为0．24,混凝处理出水具有一定的可生化性;对混凝处理出水用SBR法进行厌氧水解2h、好氧曝气9h的生物处理后,出水COD低于150mg／L,COD去除率在80％左右。     

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。     

酸析—微电解—Fenton试剂氧化联合工艺预处理苯达松废水

采用酸析—微电解—Fenton试剂氧化联合工艺预处理苯达松废水。考察了酸析pH、铸铁粉加入量、微电解时间、双氧水加入量、Fenton试剂氧化时间等因素对废水处理效果的影响。实验结果表明:最佳工艺条件为酸析pH 3.0,铸铁粉加入量1.0 g/L,微电解时间2 h,Fenton试剂氧化时间4 h,双氧水加入量25 m L/L;在最佳工艺条件下处理初始COD为22 500 mg/L、BOD5/COD为0.08、色度为2 500倍的苯达松废水,总COD去除率为96.2%,出水COD为858 mg/L,出水色度为150倍,BOD5/COD为0.38;采用微电解—Fenton试剂氧化联合工艺预处理酸析后的苯达松废水,处理效果远高于单独微电解和单独Fenton试剂氧化工艺。     

Fenton试剂强化微电解工艺预处理难降解含氰农药废水

采用Fenton试剂强化微电解反应预处理难降解含氰农药废水.实验结果表明,在总反应时间为3.0 h、反应开始时加入1 mL/L H2O2、反应1.5 h后再加入3mL/L H2O2的条件下,出水COD为372.0 mg/L,COD去除率可达80.2％,出水p(CNˉ)为2.2 mg/L,色度为20倍,BOD5/COD为0.35,可实现处理效果与经济成本的最优化.采用紫外-可见光谱分析处理后废水,发现Fenton试剂强化微电解反应可破坏部分微电解作用难以降解的有机物,但对苯环的降解能力均有限.     

油田钻井废水深度处理技术

采用化学混凝-铁炭微电解-电渗析技术对钻井废水进行了深度处理实验。实验结果表明：废水pH和反应时间是影响铁炭微电解处理效果的重要因素,当废水pH为1．5,反应时间为120min时,COD去除率为50％;在电渗析除Clˉ过程中,采取直流方式出水时,在进水流量为20L／h、操作电压为30V、运行时间为15min的条件下,Clˉ去除率可达75％;而采取循环方式出水时,运行时间是影响电渗析除Clˉ效果的主要因素,当运行时间大于等于60min时,出水中Clˉ的质量浓度低于350mg/L,达到DB51／190-1993（四川省污水排放标准》中的三级排放标准。     

Fenton氧化-混凝-SBR工艺处理糠醛废水

采用Fenton氧化-混凝-SBR工艺处理糠醛废水.实验结果表明:Fenton氧化-混凝预处理糠醛废水时,在废水中硫酸亚铁和过氧化氢浓度分别为57.60 mmol/L和5.22 mol/L、pH为2～3的条件下,废水处理后COD可达500 mg/L以下;再经SBR工艺处理,水力停留时间为18 h,最终出水COD去除率可达99.67%.     

灭多威农药废水处理技术

采用酸化、氧化、铁炭微电解、兼氧-好氧生化技术处理灭多威农药生产废水（简称废水）。实验结果表明：废水经酸化处理后可回收H2S和CH3SH,经氧化处理后可去除废水的恶臭气味,经铁炭微电解处理后COD总去除率平均为90．7％,废水可生化性指标BOD5／COD从0升至0．30以上;预处理后的废水再经过兼氧＋好氧生化处理,COD达到GB8978-1996（污水综合排放标准》中的一级标准100mg/L以下。     

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.     

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.     

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.     

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.     

Solubility and Potential Mobility of Heavy Metals in Two Contaminated Urban Soils from Stockholm,Sweden

The solubility and potential mobility of heavy metals (Cd, Cu,Hg, Pb and Zn) in two urban soils were studied by sequential andleaching extractions (rainwater). Compared to rural (arable) soils on similar parent material, the urban soils were highlycontaminated with Hg and Pb and to a lesser extent also with Cd,Cu and Zn. Metal concentrations in rainwater leachates were related to sequential extractions and metal levels reported fromStockholm groundwater. Cadmium and Zn in the soils were mainly recovered in easily extractable fractions, whereas Cu and Pb were complex bound. Concentrations of Pb in the residual fractionwere between two- and eightfold those in arable soils, indicatingthat the sequential extraction scheme did not reflect the solidphases affected by anthropogenic inputs. Cadmium and Zn conc. inthe rainwater leachates were within the range detected in Stockholm groundwater, while Cu and Pb conc. were higher, whichsuggests that Cu and Pb released from the surface soil were immobilised in deeper soil layers. In a soil highly contaminatedwith Hg, the Hg conc. in the leachate was above the median concentration, but still 50 times lower than the max concentration found in groundwater, indicating the possibilityof other sources. In conclusion, it proved difficult to quantitatively predict the mobility of metals in soils by sequential extractions.     

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.     

Biodegradation of Injection Molded Starch-Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) Blends in a Natural Compost Environment

Injection molded specimens were prepared by blending poly (hydroxybutyrate-co-valerate) (PHBV) with cornstarch. Blended formulations incorporated 30% or 50% starch in the presence or absence of poly-(ethylene oxide) (PEO), which enhances the adherence of starch granules to PHBV. These formulations were evaluated for their biodegradability in natural compost by measuring changes in physical and chemical properties over a period of 125 days. The degradation of plastic material, as evidenced by weight loss and deterioration in tensile properties, correlated with the amount of starch present in the blends (neat PHBV < 30% starch < 50% starch). Incorporation of PEO into starch-PHBV blends had little or no effect on the rate of weight loss. Starch in blends degraded faster than PHBV and it accelerated PHBV degradation. Also, PHBV did not retard starch degradation. After 125 days of exposure to compost, neat PHBV lost 7% of its weight (0.056% weight loss/day), while the PHBV component of a 50% starch blend lost 41% of its weight (0.328% weight loss/day). PHB and PHV moieties within the copolymer degraded at similar rates, regardless of the presence of starch, as determined by ¹H-NMR spectroscopy. GPC analyses revealed that, while the number average molecular weight (Mn) of PHBV in all exposed samples decreased, there was no significant difference in this decrease between neat PHBV as opposed to PHBV blended with starch. SEM showed homogeneously distributed starch granules embedded in a PHBV matrix, typical of a filler material. Starch granules were rapidly depleted during exposure to compost, increasing the surface area of the PHBV matrix.