负荷及盐度对好氧颗粒污泥EPS的影响

研究了序批式反应器(SBR)内好氧颗粒污泥在不同有机负荷(1.6 kg COD/（m³·d）和8 kg COD/（m³·d)）和不同含盐(2.5%和5.0%)条件下胞外聚合物(EPS)的变化情况,并对EPS、比耗氧速率(SOUR)和孔隙率之间的关系作了进一步探讨。结果表明：在SBR反应器中,负荷较含盐量对好氧颗粒污泥EPS变化的影响要显著,且EPS糖成分和SOUR之间、EPS蛋白成分和孔隙率之间均呈负相关。另外,高负荷条件下的系统稳定性要优于低负荷。     

厌氧氨氧化无纺滤布生物膜反应器的运行

氧气是厌氧氨氧化菌的抑制因素,通过无纺滤布生物膜系统内部形成适合厌氧氨氧化菌的厌氧环境,运行62 d,实现0.617 kg N/(m³·d)氮容积去除负荷,稳定运行阶段氨氮和亚硝氮的去除率分别为97.9％和98.7％;98 mg N/L NO^-₂-N经24 h接触产生完全抑制,通过将进水亚硝氮浓度降至20～40 mg N/L,运行31 d,成功恢复厌氧氨氧化活性,试验末期氮容积去除负荷为0.641 kg N/(m³·d)。     

不同流向BAF硝化影响因素的对比试验

在温度、水力负荷、气水比、氨氮负荷、有机物负荷等硝化影响因素同等变化的情况下,进行了不同流向单级陶粒BAF硝化效果的对比试验研究。结果表明,UBAF的硝化效果和稳定性优于DBAF。若在同一反应器中同时去除有机物和氨氮,UBAF的经济气水比为3∶1～6∶1,DBAF的经济气水比为3∶1～5∶1。当进水有机物负荷<11 kg/(m³·d),有机物和氨氮的负荷比<5时,UBAF和DBAF的氨氮去除率相差不大。在较高COD浓度下,硝化菌在DBAF中与异氧菌的竞争能力不如UBAF。两级BAF的第一级宜为UBAF,但DBAF可能更适于作为二级滤池以提高系统稳定性、反硝化效率以及出水水质。     

BAF处理生活污水过程中同步去除H2S的试验研究

采用曝气生物滤池处理生活污水的过程中,以混和臭气的空气为气源,以掺入了陶粒和铁炭颗粒的复合填料为载体,研究了反应器的运行条件和参数,结果表明,以混合臭气的空气作为气源对污水处理过程的需氧量基本无影响。当反应器的进气量为40 L/h,进水容积负荷和进气H2S的浓度分别在0.3～1.6 kg COD/(m³·d)和0.8～2.3 mg/m³之间变化时,可以实现出气和出水中H₂S和COD分别小于0.04 mg/m³和90 mg/L,满足同时达标排放的要求。H₂S的同步去除可能是通过微生物的氧化分解和形成FeS沉淀来实现的。     

炭纤维载体固定床厌氧发酵启动运行效果实验

以开发高效率、抗冲击性能强的高浓度有机废水沼气发酵技术为目的,用传统的 UASB反应器作为对照,研究了以炭纤维为生物膜载体的固定床厌氧反应器的启动运行效果。反应器进口废水 COD 为 5 000 mg/L, 水力停留时间 (HRT) 由213 h 逐步缩短为35 h,进水有机容积负荷(OLR)由0.56 kg COD/ (m³·d)提到3.45 kg COD/(m³·d)。结果表明,固定床反应器厌氧发酵的效率比对照高,出水 pH 值也比对照稳定;运行到第 50 d 时,固定床厌氧反应器和对照的 COD去除率分别由第 7 d 的36.56%和33.58%上升到87.9%和62.6%;固定床厌氧反应器的容积比产气率最高为1.16 m³/(m³·d),累计产气量为415.59 L,而对照的容积比产气率最高值仅为0.31 m³ /(m³·d),累计产气量为 71.66 L,前者最高容积比产气率和累计产气量分别是后者的3.74倍和5.78倍。固定床厌氧反应器的启动速度、COD 去除率和产甲烷效率显著地高于对照反应器。     

改进型升流式固体反应器处理猪粪污新工艺研究

对传统升流式固体反应器（USR）进行改进,反应器内设置专用搅拌器,搅拌器间歇开启,在保留USR各项优势的前提下,使料液与厌氧微生物接触更充分,反应温度更均匀,提高产气率,同时还解决了传统USR的“结壳”问题,提高了反应器的传质效率、甲烷产气率和COD去除效果。进料含固量在12.1%时,水利停留时间为17 d,反应器最高容积负荷达到4.9 kg COD/(m³·d),产气速率为2.55 m³/(m³·d),产气率达到0.359 m³/kg干猪粪。     

MBR工艺处理含50%海水的污水试验研究

采用MBR工艺对含50%海水的污水生物处理进行了试验研究。实验条件为进水COD为300～2 600 mg/L,NH₃-N为50～300 mg/L,pH值为6～9,混合液污泥浓度为7 000 mg/L,溶解氧浓度为2～4 mg/L,温度为20～25℃。试验结果表明,系统的最佳运行条件为：有机负荷＜3.2 kg COD/（m³·d）,氨氮负荷＜0.35 kg/（m³·d）,pH值在7.5～8.5之间,HRT＞12 h。在此条件下,COD与氨氮的去除率可同时达到90%。高盐环境下微生物所分泌的大量胞外多聚物是造成MBR工艺处理含盐废水过程中膜污染的主要原因。     

NO2对颗粒污泥甲烷化动力学特性的影响

采用间歇试验方法，以乙酸和乙酸盐混合物为基质，对取自EGSB反应器具有厌氧甲烷化反硝化与厌氧氨氧化活性的颗粒污泥的甲烷化动力学以及NO₂影响进行研究。无NO₂时，最大比基质降解速率为0.158 mg COD/mg VSS·h，半饱和常数为464 mg COD/L，甲烷的产率系数为0.254 mL CH₄/mg COD。添加微量NO₂对甲烷化有抑制作用，抑制程度随着微量NO₂浓度的增高而增大，在NO₂浓度为30.36 mg/m³、50.6 mg/m³、101.2 mg/m³、202.4 mg/m³和303.6 mg/m³条件下，甲烷化抑制程度分别为7.40％、11.87％、27.56％、39.75％和43.24％，外推得NO₂的甲烷化半抑制浓度IC₅₀值为383.8 mg/m³。NO₂气氛下甲烷化动力学可用反竞争性抑制动力学进行描述，最大比基质降解速率为0.148 mg COD/mg VSS·h，半饱和常数为396 mg COD/L，NO₂抑制系数为250 mg/m³。     

降低负荷以提高反硝化颗粒污泥的稳定性

在上流式污泥床反应器（USB）内,接种好氧活性污泥,以甲醇为碳源,NO-3为电子受体,经过40多d培养,得到良好的反硝化颗粒污泥,粒径2～3 mm,MLSS为36 g/L,氮去除速率和COD去除速率分别在0.15 g NO₃-N/(g VSS·d)和0.8 g COD/(g VSS·d)。当负荷提高至6.44 g NO₃-N/(L·d)继续运行1周后,观察到反应器内颗粒污泥出现上浮,浓度降低,颗粒粒径多数在3～5 mm,外观呈乳白色。为恢复反应器稳定运行,当负荷降至3.86 g NO₃-N/(L·d)时,上浮现象减轻,当负荷降至2.57 g NO₃-N/(L·d)时,上浮现象消失,颗粒污泥密度由不稳定时的1.0018 g/cm³提高到1.0126 g/cm³,颗粒粘连现象基本消失,污泥氮去除速率在0.19 g NO₃-N/(g VSS·d),连续运行30 d,系统保持稳定。分析认为,颗粒污泥表面微生物生长速度过快是导致不稳定的主要因素,较长的泥龄有利于系统稳定。     

有机负荷对膜-生物反应器硝化性能的影响

采用厌氧动态膜-生物反应器(AnDMBR)组合自养膜-生物反应器(MBR)工艺,研究冬季低温条件下系统的硝化效果以及TP的去除效果,并与单级MBR工艺进行对比。结果表明:(1)AnDMBR对COD的去除率基本保持在50%～60%,AnDMBR组合自养MBR工艺对COD的去除率为80%～85%;单级MBR工艺对COD的去除率为80%左右。(2)总体上,AnDMBR组合自养MBR工艺对NH4+-N的去除率大于95%;单级MBR对NH4+-N的去除效果比AnDMBR组合自养MBR工艺差。(3)AnDMBR组合自养MBR工艺中,出水NO2--N与NO3--N均有积累;单级MBR工艺中,出水NO2--N积累不明显。(4)相对于亚硝酸盐氧化菌(NOB),氨氧化菌(AOB)对有机负荷更敏感,当有机负荷高时,AOB更易受到异养菌活动的抑制;当有机负荷降低、异养菌活性减弱时,AOB活性明显增强,系统的硝化效果得到明显改善。(5)AnDMBR组合自养MBR工艺对TP的去除率高于80%,单级MBR工艺稳定后对TP的去除率仅为20%～30%。(6)从呼吸速率和硝化速率可知,自养MBR的硝化效果优于单级MBR。     

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

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.     

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.     

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。     

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.     

Aerobic and anaerobic degradation of profluralin and trifluralin

Abstract

The degradation of profluralin [N‐(cyclopropylmethyl)‐α,α,α‐trifluoro‐2,6‐dinitro‐N‐propyl‐]p‐toluidine] and trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) was studied under aerobic and anaerobic soil conditions. Three soils (Goldsboro loamy sand, Cecil loamy sand, Drummer clay loam) were each treated with 1 ppmw herbicide; anaerobic conditions were maintained by flooding. Soil samples were extracted monthly and subjected to TLC analysis. No degradation was detected in sterile controls. Aerobic degradation of both herbicides was greatest in the Cecil loamy sand soil over the entire incubation period. Degradation of profluralin in Cecil soil under aerobic conditions was 86 percent after 4 months with three products detected; 83 percent of the trifluralin was degraded with two products detected. Anaerobic degradation accounted for 72 percent of the profluralin and 78 percent of the trifluralin after 4 months. Degradation of both herbicides increased with incubation time for the first 3 months and decreased slightly thereafter. Generally there was more extensive degradation (percent and in number of products formed) of profluralin than trifluralin under the conditions tested. More degradation products were detected for both herbicides under aerobic conditions than under anaerobic conditions.