潜流、垂直流人工湿地污染物净化效果及耐污染负荷冲击能力研究

依托建立在新沂河河漫滩上的人工湿地中试工程进行现场试验,研究分析潜流和垂直流2种人工湿地对污染河水的净化效果及其耐污染负荷冲击能力。结果表明:在相同的进水高锰酸盐指数浓度条件下,垂直流对高锰酸盐指数的净化效果明显优于潜流;2种人工湿地对NH4+-N的去除率均比较高(平均去除率均高于80%),且没有明显差异;2种人工湿地构造不同引起的水流运行方式及截留、过滤作用的差异对高锰酸盐指数的去除影响较大,而对NH4+-N去除的影响较小;进水污染负荷变化对人工湿地污染物去除的影响显著,垂直流耐高锰酸盐指数污染负荷冲击能力明显强于潜流,而对NH4+-N污染负荷变化,两者都表现出了较强的耐受能力,差异不明显。     

水力停留时间变化对2种人工湿地净化效果的影响

依托建立在新沂河河漫滩的人工湿地中试工程开展现场实验,研究分析水力停留时间变化对2种人工湿地污染物净化效果的影响。结果表明:水力停留时间的变化显著影响潜流和垂直流湿地污染物净化的效果,2种湿地高锰酸盐指数和氨氮(NH4+-N)去除效果随水力停留时间的变化均呈现先上升后下降的趋势。垂直流人工湿地显示出比潜流湿地更好、更稳定的污染物净化效果,其高锰酸盐指数和NH4+-N去除效果的最佳停留时间均出现在2 d左右,2种污染物的去除率分别达到93.1%和87.7%;而潜流湿地在水力停留时间为2 d左右时高锰酸盐指数去除率最高,达到92.3%,在2.5 d左右的时候NH4+-N去除率最高,达到81.5%。潜流和垂直流湿地都适合应用于新沂河污染河水的处理,在设计和实践应用中,两者的水力停留时间参数均可设定为2 d。     

水深对表面流人工湿地污染河水处理系统运行效果的影响

基于中试系统一年的连续运行监测,研究了水深对芦苇表面流人工湿地污染河水处理系统的影响。结果表明,水深对表面流人工湿地污染河水处理系统运行效果有很大影响,在进水COD、氨氮、总氮和总磷等分别为36±4.46、0.92±0.47、6.27±2.01和0.13±0.05 mg/L条件下,水深50 cm时处理效果最好,COD、氨氮、总氮和总磷去除率分别达到42.75%、58.42%、56.94%和43.24%。综合污染物去除效果和人工湿地建设工程量,芦苇表面流人工湿地的水深宜采用50 cm。人工湿地系统中植物光合生理和溶解氧等研究表明,水深主要通过影响植物生长和溶解氧等而影响人工湿地的水质净化效果。     

水平潜流人工湿地处理太原市城市再生水的运行效能

以山西省太原市某污水厂的高氮低碳尾水为研究对象,开展基于3床并联的水平潜流人工湿地处理尾水的中试研究。研究结果表明,该人工湿地系统启动2个月进入稳定运行期;稳定运行期3个床体的出水水质除TN外其余指标均满足《地表水环境质量标准》（GB3838—2002）中Ⅳ类水体标准,TN指标满足《城镇污水处理厂污染物排放标准》（GB18918．2002）中一级A标准,该湿地系统出水可直接用于补充景观用水;稳定运行期3床的植物与基质的配置更适合处理同类尾水,3个床体对各污染物的去除效果均为3床〉2床〉1床;本系统中填料对污染物处理效果的影响大于植物对污染物处理效果的影响,最优填料顺序依次为沸石、砾石和钢渣,最适植物栽种顺序为芦苇、香蒲、美人蕉、黄菖蒲和芦苇。     

基于煤矸石?沸石自动改性的潜流人工湿地填料组合方案研究

针对传统砾石填料容易造成堵塞,导致潜流人工湿地处理效果变差的问题,开展填料优化选择研究。结果表明,煤矸石/沸石/砾石这一填料组合方案大大延长了潜流人工湿地的堵塞周期,比传统砾石填料组合至少晚6d,对COD、氨氮、总磷的平均去除率分别提高26.4、9.4、18.7百分点,堵塞位置向下部移动30cm,水头损失日均增加量和孔隙率变化量日均增加值分别低0.01cm和0.02%。     

表流-水平流复合人工湿地对高污染河水的净化

为了研究表流-水平流复合人工湿地对高污染河水的净化效果及植物对复合湿地中二级潜流湿地的影响作用,实验构建了表流+芦苇水平潜流和表流+无植物水平潜流复合人工湿地。在相同的水力负荷下连续运行一年的结果表明,复合人工湿地对高污染河水中TN、NH3-N、TP、COD、BOD5和SS的去除率分别为57.3%~63.1%、65.7%~68.1%、69.4%~82.7%、85.3%~86.3%、96.7%~96.9%和97.9%~98.2%,种有植物的二级潜流湿地具有更好的脱氮和除磷效果;表流湿地作为复合湿地的第一级能够有效去除大部分的有机污染物和悬浮物,进而避免二级潜流湿地的堵塞,并利于二级潜流湿地的脱氮除磷的进行;复合湿地对有机物和悬浮物的去除不受季节性波动的影响,但是其脱氮效果受季节波动的影响较大。     

潜流式人工湿地基质堵塞问题对策研究

基质堵塞是人工湿地长期稳定运行最关键的问题.针对滇池湖滨福保人工湿地运行后潜流湿地基质严重堵塞的问题,分析造成基质堵塞的原因,从工艺路线、碎石床结构、填料径粒和布水方式等方面对原有人工湿地进行分析研究,找出堵塞原因,提出技术改造方案,并经过工程模型实验进行验证,在此基础上确定"预处理-潜流湿地(垂直流)-调节池-潜流湿...     

不同水力负荷率对潜流人工湿地内部污染物迁移转化的影响

为深入研究污染物在潜流人工湿地各填料层内的迁移转化规律,提高潜流人工湿地污染物降解效率,考察了4种进水水力负荷率(HLR,0.15、0.35、0.55、0.80 m~3/(m~2·d))下潜流湿地填料层内部不同区域DO、COD和氨氮浓度分布。结果表明:HLR为0.35m~3/(m~2·d)时,湿地内部DO浓度水平最高,湿地系统污染物处理效果最好,COD、氨氮去除率分别为93.32%、90.16%,COD及氨氮的主要降解区域分别为湿地0~60、0~40cm深度处,60cm深度以下DO水平较低,为污染物降解低效区,可研发新技术提高湿地底层DO水平以提高COD及氨氮去除效果。     

不同类型潜流湿地处理养猪废水的对比

针对养猪废水的水质特点,在同等条件下开展了2种类型潜流湿地处理效果的对比研究。实验结果表明,水平潜流湿地(HSSF)与垂直潜流湿地(VSSF)由于结构设计的不同造成其布水方式和系统内部水力流态的不同,从而导致了两系统对养猪废水处理效果的差异;当水力负荷为0.02 m3/(m2.d)时,两系统对养猪废水中COD的平均去除率分别为93.18%和93.10%,对TN的平均去除率分别为53.44%和81.43%,对NH4+-N的平均去除率分别为52.64%和84.62%,对TP的去除率分别为88.41%和95.71%;垂直潜流湿地可充分利用填料层,可增强系统的复氧能力,还可实现填料层中好氧区、缺氧区和厌氧区的共存,使硝化作用与反硝化作用在同一系统内完成,提高了系统的脱氮能力,而且改善了养猪废水中其他污染物的去除效果。因此,结合处理效果和出水水质的稳定性,对于浓度较高的畜禽养殖废水,选择垂直潜流湿地较为合适。     

预曝气+垂直潜流人工湿地处理农村生活污水工程应用

传统无动力垂直潜流人工湿地,由于内部溶解氧的不足,存在除污能力下降、填料堵塞等问题。本研究采用预曝气的人工增氧方式,设计预曝气+垂直潜流人工湿地模式,以厌氧池+微曝气生物接触池+两级复合垂直流人工湿地的组合工艺,建设晋城市巴公镇农村生活污水治理项目中试端和应用示范端,探讨了实际工程应用对农村生活污水的治理效果,以及预曝气对复合垂直流人工湿地的影响。结果表明,经过8个月的运行,应用示范端出水中TN、NH₄⁺-N和COD值均满足设计出水水质要求,平均去除率分别为88.3%、93.7%和77.4%,且抗冲击能力较强、不易受冬季低温影响;对TP的去除效果较不稳定,对比中试端对TP的平均去除率94.3%,应用示范端对TP的平均去除率仅为17%;预曝气的人工增氧方式,使得系统中一级复合垂直流人工湿地对污水中TN、NH₄⁺-N、TP和COD的平均去除率分别提高了14.9%、6.8%、4.6%和10.1%。     

Optimization of Height of Release of Air Pollutants

A number of key projects in the Environmental Protection Agency (EPA) particulate R&;D program having applicability to industry are presented. For electrostatic precipitators (ESP) there is presented the result of work on large diameter discharge electrodes which provide a decrease in penetration of up to a factor of 4 when compared to conventional small diameter electrodes. Also discussed is the multistage ESP which provides a collection efficiency that would require a collecting plate area 4 or 5 times larger with conventional ESP technology. The E-SOX technology makes use of the multistage concept to free up space in the ESP for SO₂ removals of up to 90%. Electrostatically augmented fabric filtration provides a reduction in pressure drop of about 5 0% as compared to conventional fabric filtration. Wind tunnel modeling of windbreaks for material storage piles indicates a potential for providing engineering design data that would allow significant emission reduction caused by wind erosion     

Investigation of the characteristics of the reflectivity of clouds

This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies).     

实验室质量管理体系内部审核的实施

在实施ISO／IEC17025：1999标准《检测和校准实验室能力的通用要求》过程中，通过实验室质量管理体系内部审核的实践与系统分析，识别出内部审核实施阶段的关键环节，提出召开首次会议、收集审核证据、确定审核发现和召开末次会议的技术方法，对提高内部审核的质量和有效性、获得可靠的审核结论具有重要意义。     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

扬中生态环境建设的思考与实践

结合扬中生态环境的基本情况和存在的不足，进行了具体分析，对扬中未来生态建设的发展方向提出了建议及实施措施。     

An application of the theory of kinematics of mixing to the study of tropospheric dispersion

The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

Comparison of methods for evaluation of activity of photocatalytic films

Objective

This work aims to investigate the correlation between the photocatalytic activity determined by methylene blue bleaching (DIN 52980), stearic acid degradation, and degradation of acetone in gas phase.

Method

The photocatalytic TiO₂ coatings included in this investigation ranged from thin commercially available coatings (Activ^TM and BioClean^TM) and ready to use suspensions (Nano-X PK1245) to lab-produced PVD and sol?Cgel coatings. XRD analysis of the photocatalytic coatings showed that all the coatings consisted of nanocrystalline anatase, although the thickness and porosity varied considerably.

Results

The study showed that the reproducibility of the activity measurements was good. However, more importantly, the investigation showed that there is a good correlation between the activities determined by the different methods even though the characteristics of the photocatalytic coatings and the organic probe molecules varied considerably.

Conclusion

The overall findings of this work suggest that there is a good correlation between the investigated methods. These results are promising for the future work concerning standardization of methods for determination of the activity of photocatalytic films.     

Impact of overexploitation of shellfish: northeastern coast of India

India has a very extensive coastline of about 7515 km, rich in diverse living resources. These resources continue to deteriorate with rampant harvesting or are altered for other uses such as aquaculture and fisheries. The present paper deals with degrading coastal habitats in northeastern India, and projects the intensity of the stress arising from the collection of tiger prawn seeds (Penaeus monodon) for aquacultural farms and molluskan shells for poultry feed and edible lime. Indiscriminate exploitation of these resources leads to a heavy reduction of the species concerned and other associated marine communities. The magnitude of such destruction has been quantified. The impacts of biodiversity loss and their after-effects on the ecobalance of this coastal system have become a matter of great concern to ecologists to maintain security and sustainability. The authors propose a public awareness program on themes relating to the importance of biodiversity for human livelihoods.