粉末活性炭对膜过滤性能的影响

向一体式膜生物反应器中投加粉末活性炭(PAC),可以显著提高膜的过滤性能,有效缓解膜的污染.研究结果表明:投加PAC的吸附作用减少了由于胞外聚合物(EPS)而引起的膜污染;膜表面PAC颗粒的存在减小了浓差极化层的厚度和水力边界层的厚度,提高了过滤物质的传递速率;膜表面形成的PAC层还可过滤微生物和胶体颗粒,减少了它们到达膜表面的数量.     

加速厌氧污泥颗粒化的研究进展

厌氧污泥颗粒化过程是一个多阶段过程,取决于操作条件、基质组成等多种因素.在简述污泥颗粒化机理及影响因素的基础上,综述了近年来加速厌氧污泥颗粒化的研究进展,指出厌氧污泥颗粒化应用前景广阔,并提出了几点建议.希望能为厌氧污泥颗粒化技术的工程实践提供一定的理论基础.     

超声去除垃圾渗滤液中的氨氮

采用超声辐照技术去除垃圾渗滤液中的氨氮.研究结果表明,超声辐照对垃圾渗滤液中的氨氮有很好的去除效果.渗滤液中氨氮超声去除的机理主要是氨氮以游离氨的形式在空化泡内发生高温热解反应,生成氮气和氢气而排出.     

城市污水石灰法深度处理工艺中有毒物质的变化规律

分别采用7-乙氧基异酚恶唑酮．脱乙基酶（EROD）活性测定法，重组人激素受体基因的酵母测试和Q67发光菌试验方法，对北京市某生活污水处理厂的进水、二沉出水以及经过石灰法深度处理后的出水中的类二恶英物质、类雌激素物质和急性毒性物质进行了分析。进水中的三类生物毒性效应物质中的急性毒性物质，可通过活性污泥法基本去除，而对类雌激素物质和类二恶英物质的去除率分别为76％和52％。经过石灰沉淀法的深度处理后，可使上述两类物质的总去除率达到95％和68％。出水中的雌激素当量水平与欧洲国家污水处理厂出水水平相当，而类二恶英物质的总浓度低于美国EPA饮用水中二恶英的最大允许浓度。展示了生物毒性测试方法在排水生态风险和工艺评价方面的应用潜力。     

臭氧-曝气生物滤池处理酸性玫瑰红染料废水

在实验室配制含酸性玫瑰红染料的印染废水，采用臭氧氧化-曝气生物滤池工艺开展处理试验。试验运行结果表明，臭氧氧化处理能提高模拟废水的可生化性，BOD／COD值由原水的0．18上升到0．36。经组合工艺处理后出水COD〈40mg／L，色度40倍以下，SS约50mg／L，处理效果良好。     

Quantitation of Hydroxyl Radicals from Photolysis of Fe(III)-Citrate Complexes in Aerobic Water (5 pp)

Background For their high photoreactivity, Fe(III)-carboxylate complexes are important sources of H2O2 for some atmospheric and surface waters. Citrate is one kind of carboxylate, which can form complexes with Fe(III). In our previous study, we have applied Fe(III)-citrate complexes to degrade and decolorize dyes in aqueous solutions both under UV light and sunlight. Results have shown that carboxylic acids can promote the photodegradation efficiency. It is indicated that the photolysis of Fe(III)-citrate complexes may cause the formation of some reactive species (e. g. H2O2 and ·OH). This work is attempted to quantify hydroxyl radicals generated in the aqueous solution containing Fe(III)-citrate complexes and to interpret the photoreactivity of Fe(III)-citrate complexes for degrading organic compounds. Methods By using benzene as the scavenger to produce phenol, the photogeneration of ·OH in the aqueous solution containing Fe (III)-citrate complexes was determined by HPLC. Results and Discussion In the aqueous solution containing 60.0/30.0 mM Fe(III)/citrate and 7.0 mM benzene at pH 3.0, 96.66 mM ·OH was produced after irradiation by a 250W metal halide light (l ≥ 313 nm) for 160 minutes. Effects of initial pH value and concentrations of Fe(III) and citrate on ·OH radical generation were all examined. The results show that the greatest photoproduction of ·OH in the aqueous solution (pH ranged from 3.0 to 7.0) was at pH 3.0. The photoproduction of ·OH increased with increasing Fe(III) or citrate concentrations. Conclusion In the aqueous solutions containing Fe(III)-citrate complexes, ·OH radicals were produced after irradiation by a 250W metal halide light. It can be concluded that Fe(III)-citrate complexes are important sources of ·OH radicals for some atmospheric and surface waters. Recommendations and Outlook It is believed that the photolysis of Fe(III)-citrate complexes in the presence of oxygen play an important role in producing ·OH both in atmospheric waters and surface water where high concentrations of ferric ions and citrate ions exist. The photoproduction of ·OH has a high oxidizing potential for the degradation of a wide variety of natural and anthropogenic organic and inorganic substances. We can use this method for toxic organic pollutants such as organic dyes and pesticides.     

Ionic liquid-containing semipermeable membrane devices for monitoring the polycyclic aromatic hydrocarbons in water

Ionic liquid-containing semipermeable membrane devices (IL-SPMDs) were developed to monitor the polycyclic aromatic hydrocarbons in water. Uptake kinetics of naphthalene, 1-methylnaphthalene, phenanthrene, pyrene, chrysene by layflat low-density polyethylene tubing (15 cm x 2 cm) filled with 0.5 ml 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid were studied in a laboratory continuous-flow system for the duration of 16 days. The device concentration factors were in the range of 830-7800 for the studied PAHs. The kinetic parameters of IL/water partition coefficients, analytes uptake rate constants and sampling rates were estimated using mathematical models. These parameters were used in the field experiment to estimate the concentrations of the PAHs in Lanzhou section of Yellow River in China, with the result in comparison with that obtained by triolein-SPMD.     

Factors influencing arsenic accumulation by Pteris vittata: a comparative field study at two sites

This study compared the factors influencing arsenic (As) accumulation by Pteris vittata at two sites, one containing As along with Au mineralization and the other containing Hg/Tl mineralization. The soils above these two sites contained high As concentrations (26.8-2955 mg kg(-1)). Although the As concentration, pH, soil cation exchange capacity and plant biomass differed significantly between the two sites, no differences were observed in the As concentrations in the fronds and roots, or the translocation factors, of P. vittata, suggesting that this species has consistent As hyperaccumulation properties in the field. The As concentration in the fronds was positively related to phosphorus (P) and potassium (K), but negatively related to calcium (Ca), at one site. This suggested that P, K and Ca influenced As accumulation by P. vittata in the field.     

混凝-生物接触氧化法处理城市污水的研究

采用混凝-生物接触氧化法处理生活小区废水,考察了不同混凝剂用量对COD、NH4-N、SS、TP的去除效果,同时研究了生物接触氧化法对COD、NH4-N等的去除以及耐冲击负荷能力.结果表明,随混凝剂用量的增加,COD、SS、TP的去除率随之增加,生物接触氧化法具有较高的抗冲击负荷能力,最大NH4-N去除负荷达到0.55 kg/(m3·d),最大有机去除负荷达到4.32 kg/(m3·d)     

吸附法烟气脱硫

燃油和煤炭在燃烧过程中会产生SO2 ,这些SO2 排入大气中 ,形成酸雨 ,严重破坏生态环境 ,危害人类健康。一个世纪以来 ,人们对烟气脱硫作出了很大的努力 ,但常见的脱硫技术具有投资大、运行费用高 ,甚至有二次污染等问题。吸附法烟气脱硫工艺简单、脱硫效率高 ,是一种具有深入研究价值与应用前景的方法