TiO2光催化降解阳离子艳红反应动力学研究

本文以沉淀法制备的TiO2为催化剂,紫外杀菌灯为光源,对阳离子艳红染料的光催化降解进行动力学研究.实验结果表明TiO2光催化降解低浓度阳离子艳红的反应为一级反应,反应动力学行为符合Langmuir-Himshelwood方程,其反应速率常数为1.87 mg/L·min.     

玻璃蚀刻液废水中氨氮和氟去除研究

研究了MAP法(Magnesium Ammonium Phosphate磷酸铵镁结晶法)和化学沉淀法对玻璃蚀刻液废水中氨氮和氟的去除效果,获得了最佳工艺参数并形成了一套玻璃蚀刻液废水处理工艺。采用N/P/Mg投加比例为1∶1∶1的两级MAP法和Ca/F投加比为1. 8的两级化学沉淀法,并在两级氨氮和氟去除反应后分别添加PAC-PAM (聚合氯化铝-聚丙烯酰胺)为40 mg/L、2mg/L和20 mg/L、1mg/L进行絮凝沉淀,最终出水氨氮和氟的去除率分别可以达到96. 8%和99. 9%;对出水进行折点加氯处理,氨氮最终去除率可达99. 9%,出水可达到国家污水综合排放标准。     

炼油废水回用于循环冷却水系统深度处理技术

为解决水资源紧缺问题,提高工业水资源的利用率,减少污水排放,采用臭氧催化氧化—活性炭吸附—石灰软化的工艺组合,深度处理炼油厂中二级处理达标排放的污水,探讨最佳工艺参数的选择,进行二级出水回用于循环冷却水的试验研究。试验表明:在臭氧氧化接触时间为40min,活性炭柱吸附通水流量为2L/h,石灰乳投加量0.32g/L、碳酸钠溶液0.06～0.10g/L、石灰软化搅拌15～20min,能使整套工艺达到最佳处理效果。小试阶段COD、氨氮、总硬度及总碱度的去除率分别达到96.00%、44.49%、64.61%、67.85%,硫酸根和氯离子均有所下降,通过整套工艺深度处理后,所得中水可作为循环冷却系统补充水。     

城市剩余污泥制备吸附剂的研究及其应用

以城市污水处理厂的剩余污泥为原料,采用化学活化法制备活性碳污泥吸附剂.通过对比不同活化剂活化效果,并对影响活化产物吸附性能的因素进行了研究.结果表明以3mol/L的ZnCl2为活化剂,活化温度为550℃,固液比为1:2.5,热解时间2h,制备的活性碳吸附剂吸附碘值为317.4mg/g,活性炭吸附剂比表面积为232.526m2/g.采用制备的活性碳吸附剂处理模拟废水COD去除效果较好.     

微波辐射棉秆制备优质活性炭研究

研究了以棉秆废料为原料，采用微波辐射氯化锌法制备活性炭的可行性，探讨了微波功率、活化时间及氯化锌浓度对产品活性炭各项指标的影响。得到了微波辐射氯化锌法制备活性炭的最佳工艺：微波功率560W、活化时间6min、氯化锌浓度50％。用此工艺条件制得的活性炭碘吸附值：1030．2mg／g、亚甲基蓝脱色力180mL／g、得率36．82％。工艺所需活化时间为传统方法的1／36，产品活性炭吸附性能超过了国家一级标准。该工艺方法为农村棉秆资源的综合开发利用找到了新的途径。     

稠化酸返排液深度处理试验研究

针对陕北某气井稠化酸返排液pH值低、SS高、COD高、矿化度高和透光率低的特点,提出采用微电解-Fenton联合工艺处理稠化酸返排液,以期达到降低返排液COD,为后续混凝和活性炭吸附处理提供有利条件。试验结果表明:在铁屑20g、活性炭15g、H_2O_2 900mg/L,微电解-Fenton联合处理2h;调节pH值至7.5左右,PAC 700mg/L、PAM 50mg/L,混凝处理30min;活性炭40g/L,活性炭吸附处理40min的条件下,处理后的稠化酸返排液pH值为7.50、SS降至15mg/L、COD降至109.3mg/L、透光率提高至99.5%,水质达到GB 8978—1996《污水综合排放标准》二级标准。     

Fenton法预处理分子筛制造废水的实验研究

采用Fenton法预处理钛硅分子筛制造废水,通过单因素实验确定其最佳工艺条件:pH=4,H2O2=120mL/L,FeSO47H2O=20g/L,反应时间为40min。结果表明,此条件下COD去除率可达80%。     

花生壳对Cr（Ⅵ）的等温吸附模型研究

在花生壳吸附剂量为1.0g、pH2.0、温度30℃、振荡速度140r/min、吸附时间360min条件下,实验研究了不同初始浓度（50 mg/L、75 mg/L、100 mg/L、125 mg/L、150 mg/L）的Cr（Ⅵ）溶液等温吸附曲线。研究结果表明,Langmuir等温吸附模型符合得更好;该吸附是一个优先吸附过程;最大饱和吸附量为6.25mg/g。     

超声波辅助提取杜仲籽油的工艺优化

以杜仲籽为原料,应用超声波辅助法提取杜仲籽油.在单因素试验的基础上,通过正交试验确定了超声波辅助提取杜仲籽油的较佳工艺条件.结果表明,杜仲籽油的较佳提取工艺条件为料液比12ml/g,提取温度50℃,提取时间15min,超声波功率225W,在该条件下杜仲籽油得率27.24%.     

LDO处理垃圾渗滤液中氮的实验研究

研究了复合金属氧化物（LDO）用于处理垃圾渗滤液中氮的可行性,并与传统吸附剂粉末活性炭（PAC）进行了比较,考察了投加量、振荡速度、吸附时间、吸附温度、pH等因素对处理效果的影响。结果表明,当垃圾渗滤液中总氮浓度为561mg/L、LDO投加量为6g/L、振荡速度为170r/min、吸附时间为60min、温度为25℃、pH值为11时,LDO对总氮的吸附量最高,达到41mg/g。在相同条件下,LDO对总氮的吸附量是PAC的2.5—3.5倍。     

Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.     

BIOLOGICAL INDICATORS AND BIOLOGICAL EFFECTS OF ESTUARINE/COASTAL POLLUTION1

ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.     

Using Paleo Reconstructions to Improve Streamflow Forecast Lead Time in the Western United States

In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.     

Journalists' views of advertiser pressures on agricultural news

All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.     

Definition Procedures Have Little Effect on Performance of Environmental Classifications of Streams and Rivers

Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.     

Urban ecological systems: scientific foundations and a decade of progress

Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.     

Neighbourhood characteristics and urban gardens in the Toledo metropolitan area: staffing and voluntarism,food production,infrastructure, and sustainability practices

Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.     

Predicting deer-vehicle collisions in an urban area

Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.     

Effect of Light on Biodegradation of Estrone, 17β‐Estradiol,and 17α‐Ethinylestradiol in Stream Sediment

Biodegradation of [A‐ring ¹⁴C] Estrone (E1), 17β‐estradiol (E2), and 17α‐ethinylestradiol (EE2) to ¹⁴CO₂ was investigated under light and dark conditions in microcosms containing epilithon or sediment collected from Boulder Creek, Colorado. Mineralization of the estrogen A‐ring was observed in all sediment treatments, but not epilithon treatments. No difference in net mineralization between light and dark treatments was observed for ¹⁴C‐E2. Net mineralization of ¹⁴C‐E1 and ¹⁴C‐EE2 was enhanced in light treatments. Extents of ¹⁴CO₂ accumulation and rates of mineralization were significantly greater for E2 than E1 under dark conditions, but were comparable under light conditions. These results indicate substantial differences in the uptake and metabolism of E1 and E2 in the environment and suggest biorecalcitrance of E1 relative to E2 in light‐limited environments. The extent of ¹⁴CO₂ accumulation and rate of mineralization for EE2 in dark treatments were less than half of that observed for E2 and generally lower than for E1, consistent with previous reports of EE2 biorecalcitrance. However, ¹⁴CO₂ accumulation and rates of mineralization were comparable for EE2, E2, and E1 under light conditions. These results indicate photoactivation and/or phototransformation/photodegradation processes can substantially enhance heterotrophic biodegradation of estrogens in sunlit environments and may play an important role in estrogen transport and attenuation.     

MANGANESE CYCLE IN IMPOUNDMENT WATER

Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.