粉煤灰/污泥烧结陶粒的研制与应用

以粉煤灰和工业污水处理站的剩余污泥为主要原材料,采用烧结法研制复合陶粒.分析了不同配方和不同烧结温度对陶粒性能的影响,以陶粒吸水率、容重为评价指标确定最佳配比和最佳烧结温度,并对陶粒用于铺设景观水底、治理城市水体进行了可行性分析.粉煤灰/污泥陶粒的容重为0.79～0.90 g/m3,吸水率为68.95%～80.01%.陶粒对水中氨氮和总磷吸附容量分别为0.03～0.05 mg/g和0.01～0.02 mg/g.     

给水厂污泥吸附Cr(Ⅵ)的性能研究

采用给水厂污泥对浓度为100 mg/L的模拟含Cr(Ⅵ)废水进行了吸附性能的研究.结果表明,给水厂污泥可吸附处理含Cr(Ⅵ)废水,吸附量可达0.89 mg/g.动力学研究结果表明,给水厂污泥对Cr(Ⅵ)的吸附符合二级吸附动力学模型,吸附速率常数(k2)为3.48×10-3g/(mg·min);热力学研究结果表明,吸附过...     

自来水厂污泥制得陶粒对污水中磷和氨氮的吸附

自来水厂在制水过程中使用了铝系、铁系无机混凝剂,故而污泥中含有较多的铝、铁成分。本研究从固体废物综合利用角度,结合自来水厂污泥成分特点,探索自来水厂污泥陶粒化后作为污水处理污染物吸附填料的可行性。通过对四种不同温度条件下煅烧制得陶粒填料的污染物吸附性能及物理化学特征的对比研究表明,4种陶粒填料对磷均有较好的吸附效果,其中以400℃条件下制得的吸附效果最好,去除率可达98%;EDS、XRD等物化表征显示了4种陶粒填料中均含有铝的氧化物,但纯度不高,含量因煅烧温度不同而有所不同,800℃条件下制得的最低;比较吸附前后填料中Al-P的含量变化,400℃条件下制得的陶粒填料Al-P吸附量最大,达448.23 mg/kg,而800℃的最低,仅为116.11 mg/kg,煅烧后陶粒中铝氧化物是这类陶粒填料对磷吸附效果主要因素。     

稻壳生物质炭对水中氨氮的吸附

以稻壳生物质为原材料,在350℃和500℃2种温度条件下制备生物质炭(BC350和BC500),采用扫面电镜(SEM)和红外光谱(FTIR)对稻壳生物质炭进行了表征。通过实验考查了稻壳生物质炭对氨氮的吸附等温线、影响因素和动态吸附。结果表明,稻壳生物质炭的平衡吸附量随着平衡浓度的增大而增大后趋缓,Langmuir方程比Freundlich方程更好地描述稻壳生物质炭吸附氨氮的行为,BC500比BC350具有更大的吸附氨氮的能力,其最大吸附量分别为5.82 mg/g和6.51 mg/g。p H和离子强度影响BC500对氨氮的吸附效果。动态吸附实验表明,BC500对氨氮的平均吸附量为1.78 mg/g。可见,稻壳生物质炭可以用作高效吸附剂去除废水中的氨氮。     

香蕉皮改性吸附剂对氨氮吸附特性

利用Na OH对香蕉皮进行改性,制备改性吸附剂,研究吸附时间、温度、p H等3个因素对其氨氮吸附性能的影响。实验结果表明,Na OH改性提高了该吸附剂对氨氮的吸附能力,在较广温度范围内,该改性吸附剂保持着较高的吸附效率,在吸附氨氮过程中氨氮去除率随着p H值增大呈上升趋势,水质呈中性和碱性时,改性吸附剂表现出较高的吸附效率。相同氨氮初始浓度条件下,在吸附剂投加量增加,氨氮去除率升高,在氨氮浓度为6 mg/L时,可达到96.78%。在20℃温度条件下,饱和吸附量理论值达到9.478 7 mg/g。改性香蕉皮吸附剂对氨氮的吸附符合伪二阶吸附动力模型,氨氮饱和吸附数据符合Langmuir和Freundlich等温吸附模型。     

城市给水厂污泥对污水中磷的动态吸附

以城市给水厂污泥为原料,制备了2种不同粒径的颗粒状吸附剂,探讨了这2种颗粒吸附剂不同应用方式动态吸附初沉池水中磷的效果,并对吸附的影响因素进行了探究。结果表明,在使用2 mm粒径的吸附剂进行动态吸附时,在颗粒投加量固液比为20 g·L~(-1)的条件下,运行8 h后,出水磷浓度最低,总磷、可溶性总磷、可溶性活性磷酸盐的出水浓度分别可达到1.52、0.27、0.16 mg·L~(-1)。干化大颗粒的固定床吸附实验结果表明,空床停留时间应控制在30 min左右,有效滤层高度为11.5 cm,滤柱连续运行前80 h,对初沉池水有良好的处理效果,为该吸附剂投入使用提供了初步依据。对给水厂污泥颗粒吸附剂进行了技术经济分析,得出颗粒吸附剂理论上处理初沉池水所需药剂费用为0.021 2元·t~(-1),具有较高的经济效益。以上结果可为给水厂的污泥在实际生产中的应用提供参考。     

响应面分析法优化造纸污泥吸附剂除磷工艺

以造纸厂废水污泥为原料,采用微波加热法制备造纸污泥吸附剂。利用制备的造纸污泥吸附剂对模拟含磷废水进行了吸附研究,探讨了吸附时间、投加量、pH值、转速和温度等因素对除磷效果的影响,并采用响应面设计法优化吸附工艺条件。结果表明,获得了最佳除磷工艺条件为吸附时间97 min,投加量6.9 g/L,pH=6,转速200 r/min,温度30℃,在此条件下磷的去除率可达99%以上。因此,造纸污泥吸附剂对磷的吸附效果良好,具有重要的实际应用价值。     

赤泥质陶粒吸附模拟酸性废水中铜离子的行为

矿山酸性废水中重金属污染较普遍,利用赤泥陶粒对模拟酸性废水中的Cu~(2+)进行净化处理。实验结果表明,当p H值为3、温度为30℃、Cu~(2+)初始浓度为150 mg/L、陶粒添加量为20 g/L、吸附时间为4 h时,Cu~(2+)的去除率达到95.06%。陶粒对Cu~(2+)的吸附符合准二级动力学模型,相关系数为0.998 3,饱和吸附量为7.412 9 mg/g;等温吸附模型中更符合Langmuir等温吸附模型,相关系数为0.993 3。处理废水后的陶粒用硫酸-硝酸浸提,浸出液中重金属离子浓度均低于国家浸出毒性标准,表明陶粒是一种很好的酸性废水处理剂。吸附饱和的陶粒用1 mol/L的Na OH溶液再生效果好。实验结果表明,陶粒对Cu~(2+)的吸附过程是物理吸附和化学吸附的共同作用。     

磁性CoFe_2O_4/MgAl-LDH去除水中的磷酸盐

采用共沉淀法制备了磁性复合材料Co Fe2O4/Mg Al-LDH,通过静态吸附实验研究了Co Fe2O4/Mg Al-LDH对磷酸盐的吸附性能,考察了吸附剂投加量、溶液p H值、吸附时间、温度、共存离子等因素对磷酸盐去除效果的影响。结果表明,在实验条件下,Co Fe2O4/Mg Al-LDH对磷酸盐的吸附量随溶液p H值的增大而逐渐降低,吸附的最佳p H值为1.5。磁性Co Fe2O4/Mg Al-LDH对磷酸盐的吸附动力学符合准二级动力学模型,吸附等温线符合Langmiur等温吸附模型,理论最大吸附容量为105.37 mg/g。吸附热力学参数表明,Co Fe2O4/Mg Al-LDH对磷酸盐的吸附是自发、吸热的过程。     

沸石改性及其去除水中氨氮的实验研究

通过实验研究了沸石改性条件及其对水中氨氮吸附去除的影响。结果表明，加热改性与无机酸改性不能显著提高沸石对氨氮的吸附量。利用NaOH改性的最佳浓度为1 mol/L，此条件下对氨氮吸附量可提高到650.68 mg/kg，为天然沸石的2.82倍。利用无机盐改性时，对氨氮吸附效果最好的是NaCl改性沸石，其次为KCl改性沸石与CaCl₂改性沸石。随着NaCl溶液浓度和改性时间的增加，改性沸石对氨氮的吸附量显著增加，可达天然沸石的3～4倍；在NaCl浓度为150 g/L与改性时间为18 h条件下，改性沸石对氨氮吸附量可达887.35 mg/kg，为天然沸石的3.84倍。     

Meta-analysis of time-series studies of air pollution and mortality: effects of gases and particles and the influence of cause of death,age, and season

A comprehensive, systematic synthesis was conducted of daily time-series studies of air pollution and mortality from around the world. Estimates of effect sizes were extracted from 109 studies, from single- and multipollutant models, and by cause of death, age, and season. Random effects pooled estimates of excess all-cause mortality (single-pollutant models) associated with a change in pollutant concentration equal to the mean value among a representative group of cities were 2.0% (95% CI 1.5-2.4%) per 31.3 microg/m3 particulate matter (PM) of median diameter < or = 10 microm (PM10); 1.7% (1.2-2.2%) per 1.1 ppm CO; 2.8% (2.1-3.5%) per 24.0 ppb NO2; 1.6% (1.1-2.0%) per 31.2 ppb O3; and 0.9% (0.7-1.2%) per 9.4 ppb SO2 (daily maximum concentration for O3, daily average for others). Effect sizes were generally reduced in multipollutant models, but remained significantly different from zero for PM10 and SO2. Larger effect sizes were observed for respiratory mortality for all pollutants except O3. Heterogeneity among studies was partially accounted for by differences in variability of pollutant concentrations, and results were robust to alternative approaches to selecting estimates from the pool of available candidates. This synthesis leaves little doubt that acute air pollution exposure is a significant contributor to mortality.     

Sources and fate of PCDD and PCDF

PCDD and PCDF were found in urban air particulates from St. Louis and Washington, D.C., and in sediments from the Great Lakes and Siskiwit Lake, Isle Royale. The similarity between the PCDD and PCDF found in air particulates and sediment samples and the presence of PCDD and PCDF in sediment from Siskiwit Lake (a location which can receive only atmospheric inputs) suggest that these compounds are emitted to the atmosphere from combustion sources. The historical input of PCDD and PCDF to dated sediment cores shows a strong increase since 1940, and this suggests that the incineration of chlorinated organic compounds is an important source of PCDD and PCDF to the environment.     

Field and laboratory studies of the fate and enantiomeric enrichment of venlafaxine and O-desmethylvenlafaxine under aerobic and anaerobic conditions

The stereoselectivity of R,S-venlafaxine and its metabolites R,S-O-desmethylvenlafaxine, N-desmethylvenlafaxine, O,N-didesmethylvenlafaxine, N,N-didesmethylvenlafaxine and tridesmethylvenlafaxine was studied in three processes: (i) anaerobic and aerobic laboratory scale tests; (ii) six wastewater treatment plants (WWTPs) operating under different conditions; and (iii) a variety of wastewater treatments including conventional activated sludge, natural attenuation along a receiving river stream and storage in operational and seasonal reservoirs. In the laboratory and field studies, the degradation of the venlafaxine yielded O-desmethylvenalfaxine as the dominant metabolite under aerobic and anaerobic conditions. Venlafaxine was almost exclusively converted to O-desmethylvenlafaxine under anaerobic conditions, but only a fraction of the drug was transformed to O-desmethylvenlafaxine under aerobic conditions. Degradation of venlafaxine involved only small stereoisomeric selectivity. In contrast, the degradation of O-desmethylvenlafaxine yielded remarkable S to R enrichment under aerobic conditions but none under anaerobic conditions. Determination of venlafaxine and its metabolites in the WWTPs agreed well with the stereoselectivity observed in the laboratory studies. Our results suggest that the levels of the drug and its metabolites and the stereoisomeric enrichment of the metabolite and its parent drug can be used for source tracking and for discrimination between domestic and nondomestic wastewater pollution. This was indeed demonstrated in the investigations carried out at the Jerusalem WWTP.     

Meta-Analysis of Time-Series Studies of Air Pollution and Mortality: Effects of Gases and Particles and the Influence of Cause of Death,Age, and Season

Abstract

A comprehensive, systematic synthesis was conducted of daily time-series studies of air pollution and mortality from around the world. Estimates of effect sizes were extracted from 109 studies, from single- and multipollutant models, and by cause of death, age, and season. Random effects pooled estimates of excess all-cause mortality (single-pollutant models) associated with a change in pollutant concentration equal to the mean value among a representative group of cities were 2.0% (95% CI 1.5-2.4%) per 31.3 μg/m³ particulate matter (PM) of median diameter <10 μm (PM₁₀); 1.7% (1.2-2.2%) per 1.1 ppm CO; 2.8% (2.1-3.5%) per 24.0 ppb NO₂; 1.6% (1.1-2.0%) per 31.2 ppb O₃; and 0.9% (0.7-1.2%) per 9.4 ppb SO₂ (daily maximum concentration for O₃, daily average for others). Effect sizes were generally reduced in multipollutant models, but remained significantly different from zero for PM₁₀ and SO₂. Larger effect sizes were observed for respiratory mortality for all pollutants except O₃. Heterogeneity among studies was partially accounted for by differences in variability of pollutant concentrations, and results were robust to alternative approaches to selecting estimates from the pool of available candidates. This synthesis leaves little doubt that acute air pollution exposure is a significant contributor to mortality.     

剩余污泥浓缩脱水投药量优化和模型建立

应用高分子阳离子絮凝剂（CPF-100）和聚丙烯酰胺（PAM）对污水厂剩余污泥进行浓缩脱水实验，研究表明：CPF-100的浓缩脱水效果优于PAM；当CPF-00投加量为1．16‰时，污泥沉降性能改善程度为37．51％；且在CPF-100投加量逐渐增大的初始阶段，污泥沉降性能改善程度随投加量的增加而增大，但CPF-100投加量也不宜过大，当CPF-100投加量超过1．16‰后，反而会使浓缩脱水效果变差。同时，建立了污泥沉降性能改善程度与絮凝剂CPF-100投加量、沉降时间之间的数学模型，其能较好地反映污水厂剩余污泥的浓缩脱水效果。     

Sorption and desorption of Cu and Cd by macroalgae and microalgae

The sorption and desorption of Cu and Cd by two species of brown macroalgae and five species of microalgae were studied. The two brown macroalgae, Laminaria japonica and Sargassum kjellmanianum, were found to have high capacities at pHs between 4.0 and 5.0 while for microalgae, optimum pH lay at 6.7. The presence of other cations in solution was found to reduce the sorption of the target cation, suggesting a competition for sorption sites on organisms. Sorption isotherms obeyed the Freundlich equation, suggesting involvement of a multiplicity of mechanisms and sorption sites. For the microalgae tested, Spirulina platensis had the highest capacity for Cd, followed by Nannochloropsis oculata, Phaeodactylum tricornutum, Platymonas cordifolia and Chaetoceros minutissimus. The reversibility of metal sorption by macroalgae was examined and the results show that both HCl and EDTA solutions were very effective in desorbing sorbed metal ions from macroalgae, with up to 99.5% of metals being recovered. The regenerated biomass showed undiminished sorption performance for the two metals studied, suggesting the potential of such material for use in water and wastewater treatment.     

骆马湖富营养化和生态状况调查与评价

为了了解骆马湖水质状况，在2005年对骆马湖富营养化状态和生态特性进行了调查，并结合“十五”期间的监测资料进行了分析。2005年骆马湖水体中总氮和总磷的平均值超《地表水环境质量标准》（GB3838-2002）中Ⅲ类，超标情况分别为0．78倍和0．54倍，达到湖库特定项目Ⅳ类水标准，骆马湖处于轻度富营养化状态。对骆马湖生态特征分析表明，由于该湖泊的形态以及“藻型浊水状态”和“泥沙型浊水状态”交替出现，遏制了湖水从高营养盐含量向全面富营养化状态演变，保障了底栖动物的良好生长环境，从而形成了骆马湖独特的环境生态平衡。     

Experimental and statistical validation of SPME-GC-MS analysis of phenol and chlorophenols in raw and treated water

A procedure based on solid-phase microextraction (SPME) and gas chromatography coupled with mass spectrometry (GC-MS) was developed and validated in order to analyse 10 phenols in water samples. The optimised conditions were obtained using polyacrylate fibre (PA), 20ml of sample volume, 10% NaCl, pH 4.0 and direct extraction at 35 degrees C and 1000rpm, for 40min. The linear range and quantification limits for these compounds by SPME-GC-MS were defined. An evaluation of the main uncertainty sources of this method is included, which allows expanded uncertainties in the 9.4-35% range for the majority of the compounds. The main source of uncertainty is associated with matrix effects. The validated method is suitable for monitoring the production and distribution of potable water and was used, in field trials, for the analysis of samples from main intakes of water (surface or underground) and from water supply system of a large area (Lisbon and neighbour municipalities).     

Copper-catalyzed chlorination and condensation of acetylene and dichloroacetylene

The chlorination and condensation of acetylene at low temperatures is demonstrated using copper chlorides as chlorinated agents coated to model borosilicate surfaces. Experiments with and without both a chlorine source and borosilicate surfaces indicate the absence of gas-phase and gas-surface reactions. Chlorination and condensation occur only in the presence of the copper catalyst. C₂ through C₈ organic products were observed in the effluent; PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed that is consistent with the observed product distributions. Similar experiments with dichloroacetylene indicate greater reactivity in the absence of the copper catalyst. Reaction is observed in the gas-phase and in the presence of borosilicate surfaces at low temperatures. The formation of hexachlorobenzene is only observed in the presence of a copper catalyst. PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed for the formation of hexachlorobenzene from dichloroacetylene.