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。     

硫酸生产中废水治理工艺的改进

采用ＮａＣｌＯ氧化共沉淀脱砷工艺处理硫酸废水，在ＮａＣｌＯ投加量１２００ｍｇ／Ｌ、铁砷比３．０、氧化终点ｐＨ３．５、聚丙烯酰胺投加量１５ｍｇ／Ｌ的条件下，处理后出水中砷含量降至１．０６ｍｇ／Ｌ，再经第二级中和沉淀后可达国家排放标准。此工艺能使砷富集于沉渣中，达到可回收的水平，此外还可大大减少含砷废渣的产生量。     

印刷电路板生产厂高浓度含油墨废水的处理

对某印刷电路板生产厂高浓度含油墨废水进行分类收集,并采用硫化沉淀—中和沉淀—混凝沉淀—催化氧化组合工艺进行处理。试验结果表明,系统运行稳定,处理效果良好,出水COD小于90mg/L,ρ(Cu2+)小于0.5mg/L,SS小于50mg/L,出水水质达到GB8978—1996《污水综合排放标准》一级排放标准。     

内电解—Fenton氧化—絮凝沉淀预处理焦化废水

采用内电解—Fenton氧化—絮凝沉淀的化学集成技术预处理焦化废水，优化了各工段的运行参数。实验结果表明：在钢铁铁屑与活性炭的体积比为1∶1的条件下，内电解工段的优化参数为进水pH 2.6~3.1、HRT=1.0 h;Fenton氧化工段的优化参数为Fe2+加入量200 mg/L、H2O2加入量1 000 mg/L、进水pH 3.0左右、反应时间1.0 h;絮凝沉淀工段的设定参数为进水pH 9.5~10.0、聚丙烯酰胺加入量1 mg/L、静置沉降0.5 h。在上述工艺条件下，该集成技术对废水的总COD去除率大于55%，处理后的废水BOD5/COD大于0.28，不添加稀释新水即可进入后续生化处理系统。该工艺占地面积小、系统结构简单、易于工业化，废水预处理成本为4~5元/t。     

聚合物驱采油废水深度处理工艺

采用UV/H2O2/O3组合工艺,并结合精细过滤技术,对含有大量残余聚丙烯酰胺的聚合物驱采油废水进行深度处理.结果表明,该工艺对废水中的聚丙烯酰胺和悬浮固体颗粒有非常好的去除效果,处理后废水的水质能够达到大庆油田含聚合物废水注水水质控制标准的要求.     

微电解/斜板沉淀/生物接触氧化处理印刷电路板废水

根据某印刷电路板企业生产废水的水质特点,对废水进行分类收集处理后,采用微电解/斜板沉淀/生物接触氧化工艺处理综合废水。工程运行结果表明,该工艺处理效果稳定,出水水质符合《污水综合排放标准》(GB 8978-1996)的一级排放标准。     

光伏企业生产废水处理工程实例

针对光伏企业废水pH值变化大,氟离子含量高,废水种类复杂等特点,对废水进行分类收集处理后,采用“混凝沉淀—水解酸化—接触氧化—过滤”工艺进行处理.工程运行结果表明,该工艺处理效果稳定,出水水质均达到《污水综合排放标准》(GB 8978-1996)一级排放标准要求.     

黄磷废水中氟化物的处理

本文叙述了黄磷废水中氟化物深度处理的工艺流程和工艺条件的选择。电解处理后的黄磷废水含有 Cl~-离子,再经石灰和聚丙烯酰胺的凝聚处理,废水中氟含量可由18—40毫克/升降至国家排放标准(10毫克/升)以下。     

聚丙烯酰胺类絮凝剂在工业废水处理中的应用

一、前言人们早就用天然明矾来处理含固体悬浮物的水,使其加速沉淀。以后又用熟化淀粉、硫酸铝、氯化铝、碱式氯化铝、硫酸亚铁等无机絮凝剂和天然高分子物质对废水进行絮凝处理。随着化学工业的发展,尤其是石油化工的发展,聚电解质开始大量用作絮凝剂。聚电解质的品种较多,但现在作为合成高分子絮凝剂的主要是聚丙烯酰胺类。由于官能团百分比及聚合度大小不一,聚丙烯酰胺有一系列性质不同的产品,通常有以下四种类型:     

燃煤电厂脱硫废水的零排放处理技术

采用化学沉淀—混凝—软化工艺对江苏某燃煤电厂湿法烟气脱硫废水进行物化法预处理,预处理后的废水再进行蒸发结晶,回收工业盐及冷凝水,最终实现了电厂脱硫废水的零排放。实验结果表明:在化学沉淀p H为9、混凝剂聚合硫酸铝铁(PAFS)加入量为2.5 m L/L、絮凝剂聚丙烯酰胺(PAM)加入量为2.0 m L/L的条件下,废水浊度可降至4.13 NTU,废水中的重金属、氟离子以及悬浮物被有效去除,预处理后废水的水质可达到GB8978—1996《污水综合排放标准》;蒸发结晶处理得到的工业盐和冷凝水分别符合GB/T 5462—2003《工业盐》的国家精制工业盐二级标准和GB 1576—2008《工业锅炉水质》的给水标准;脱硫废水的工业盐产率量为30 g/L。     

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.     

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.     

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.