废水厌氧(水解)--好氧生物组合处理工艺研究进展

比较了厌氧(水解)法和好氧法废水生物处理技术的优缺点，分析了厌氧(水解)—好氧组合工艺的主要优势；并根据组合工艺在空间和时间上的4种不同实现形式，总结了近年来国内外组合工艺的应用现状和发展趋势。     

提高异丙醇废水可生化性的试验研究

感光材料行业排出的异丙醇废水,BOD5／COD为0．40左右,经水解酸化处理后BOD5／COD提高至0．05左右,证实了水解酸化处理具有提高异丙酸废水可生化性的功能。在进水COD为2000－3000mg／L条件下,用水解酸化－好氧生化工艺处理,COD总去除率可达90％左右,BOD5总去除率可达95％左右,均明显优于平等对照组传统活性污泥法的处理效果。     

难降解有机物的水解－酸化预处理

综述了水解－酸化作为难生物降解有机废水预处理工艺的应用情况，介绍了水解－酸化工艺的原理，分析了影响水解－酸化处理效果的部分因素。指出，对于难降解有机废水，水解－酸化是一种有效的预处理手段。     

难降解有机物的水解——酸化预处理

综述了水解－酸化作为难生物有机废水预处理工艺的应用情况，介绍了水解－酸化工艺的原理，分析了影响水解－酸化处理的部分因素，指出，对于难降解有机废水，水解－酸化是一种有效的预处理手段。     

厌氧-好氧处理变性淀粉生产废水

南开大学膜分离技术研究中心将膨胀颗粒污泥床(EGSP)处理工艺与活性污泥好氧处理工艺相结合，处理天津顶峰淀粉厂变性淀粉生产废水。该厂     

专利文摘

一种油田超稠油废水的深度处理工艺该发明公开了一种油田超稠油废水的深度处理工艺。包括以下步骤:1)将经过破乳和物化预处理的超稠油废水冷却至35～40℃;2)采用厌氧处理和好氧处理组合工艺生物降解冷却后废水;3)采用吸附剂吸附处理经步骤2处理的废水,控制出水COD≤50mg/L。该发明降低了生化处理负荷,     

樟脑和龙脑等萜类化合物废水处理工艺

采用隔油－混凝－气浮－厌氧－好氧组合工艺处理某化工厂樟脑、龙脑等萜类化合物废水，对处理装置运行的主要影响因素进行了分析研究并对运行难点提出了解决途径。运行结果表明，该工艺对含高浓度硫酸根的萜类化合物生产废水的处理效果很好，出水COD在86mg/L以内，低于广州污水排放标准。     

微碱解-厌氧水解-SBR好氧生化法处理有机磷农药废水

介绍了微碱解——厌氧水解——SBR好氧生化法处理有机磷农药废水的工艺流程、工艺参数和处理效果。废水处理设施运行结果：废水COD去除率平均为90.1%,BOD5去除率平均为94.2%,TP去除率平均为84.9%。     

AO1O2工艺处理染色废水

报导了豆腐营工业区污水集中控制示范工程，采用水解酸化（Ａ）－接触氧化（Ｏ１）－合建式氧化沟（Ｏ２）净化组合工艺处理染色废水的运行情况。该工艺具有处理效果好、运行稳定、投产快、操作管理简便、占地少、投资省、处理成本低等优点。     

湿法腈纶废水的生化处理

采用水解酸化—固定化微生物流化床—氧化混凝联合工艺处理湿法腈纶废水.该工艺采用的高效菌微生物固定化技术及新型氧化混凝技术均对湿法腈纶废水有较好的处理效果.实验结果表明:在水解酸化温度为42℃、水解酸化运行周期为20 h的条件下,接种活性污泥和高效菌的SBR的COD去除率为26.0％;在新型氯铁型氧化混凝剂加入量为15 mL/L的条件下,混凝出水COD可降至66 mg/L.水解酸化—固定化微生物流化床—氧化混凝联合工艺的总COD去除率可达89.4％.     

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.