不同基质共代谢降解2,4,6-三硝基苯酚的研究

以葡萄糖、可溶性淀粉、乙酸钠和苯酚作为共基质，通过35℃恒温生化培养箱缺氧驯化污泥，间歇恒温振荡试验研究了在不同共代谢基质条件下，2,4,6-三硝基苯酚（TNP）的缺氧降解性能。结果表明，经过驯化的微生物加入葡萄糖和苯酚作为碳源，在TNP∶苯酚∶葡萄糖为10∶3∶100的比例下，TNP生物降解率可以从不加碳源时的31.2%提高到86.6%；不同共基质条件下TNP的降解均符合一级反应动力学方程，反应速率常数大小依次是K_苯酚＜K_葡萄糖＜K_{葡萄糖+苯酚}，其中葡萄糖和苯酚同时作为共基质时TNP降解速率常数最大为0.019 h^-1。     

三氯乙烯好氧生物降解的初步研究

工业溶剂三氯乙烯(TCE)是地下水污染物中发现的最普遍的氯代化合物。本研究的目的是评价以葡萄糖为初始基质时好氧条件下TCE生物降解的可行性，以及以TCE为单一基质时的生物降解情况。微生物培养是在好氧条件下以驯化好的活性污泥作为接种体。实验结果表明，在25℃时，葡萄糖可以在好氧条件下作为共代谢基质使TCE发生生物降解，其一级反应速率常数为0．3212d^-1，半衰期为2．16d；TCE可以作为单一基质发生好氧生物转化，其一级反应速率常数为0．2624d^-1，半衰期为2．64d；降解过程中无二氯乙烯(DCE)和氯乙烯(VC)等中间产物的形成；表明葡萄糖共代谢降解TCE的速率大于TCE作为单一基质的降解速率。     

共基质体系下漆酶介体系统降解氮杂环化合物的研究

采用2,2-连氮-双-(3-乙基苯并噻吡咯啉-6-磺酸)(ABTS)作为介体,与纯漆酶组成漆酶介体系统(LMS),分别研究了单基质和共基质体系下LMS对氮杂环化合物的降解。结果表明:(1)LMS对单基质和共基质体系中的吲哚的降解反应很快达到平衡,约为1h。(2)共基质体系中吡啶的引入,对吲哚的降解没有明显的促进或抑制作用;共基质体系中喹啉的引入,对吲哚的降解有较小的促进作用,而同时引入吡啶和喹啉,一定程度上也促进了吲哚的降解。(3)喹啉不能被LMS所降解。共基质体系中吲哚的引入,对吡啶的降解有一定的抑制作用;对喹啉的降解有一定的促进作用。(4)在LMS的作用下,推断吲哚生成的中间产物是氧化吲哚和靛红;吡啶生成的产物是戊二醛和戊二酸;喹啉最先生成2-羟基喹啉。     

三氯乙烯好氧生物降解的初步研究

工业溶剂三氯乙烯 (TCE)是地下水污染物中发现的最普遍的氯代化合物。本研究的目的是评价以葡萄糖为初始基质时好氧条件下TCE生物降解的可行性 ,以及以TCE为单一基质时的生物降解情况。微生物培养是在好氧条件下以驯化好的活性污泥作为接种体。实验结果表明 ,在 2 5℃时 ,葡萄糖可以在好氧条件下作为共代谢基质使TCE发生生物降解 ,其一级反应速率常数为 0 32 12d-1,半衰期为 2 16d ;TCE可以作为单一基质发生好氧生物转化 ,其一级反应速率常数为 0 2 6 2 4d-1,半衰期为 2 6 4d ;降解过程中无二氯乙烯 (DCE)和氯乙烯 (VC)等中间产物的形成 ;表明葡萄糖共代谢降解TCE的速率大于TCE作为单一基质的降解速率。     

不同共代谢基质下四氯乙烯厌氧生物降解研究

分别用葡萄糖、乳酸盐和醋酸盐作为驯化好的厌氧污泥的共代谢基质 ,对四氯乙烯 ( PCE)的降解进行研究。结果表明 ,PCE是通过还原脱氯发生生物降解的。实验的回归结果表明 ,反应均符合一级动力学方程 ;反应速率常数的大小依次为 k乳酸盐 >k葡萄糖 >k醋酸盐 ;以乳酸盐作为共代谢基质时 ,PCE的降解速率较快 ,在实验条件下乳酸盐是最合适的共代谢基质     

基于不同共代谢碳源降解4-氯苯酚的研究

鉴于氯酚废水在环境中的广泛存在及其显著的难生物降解性,采用序批式生物反应器(SBR)处理4-氯苯酚(4-CP)废水,探讨不同共代谢碳源降解4-CP对污染物去除和活性污泥中胞外聚合物(EPS)的影响。结果表明:分别以可溶性淀粉(DS)和乙酸钠(SA)为共代谢碳源时,4-CP可被有效降解去除;当两个SBR处于稳定运行阶段时,其进水COD、氨氮、磷酸盐和4-CP均具有良好的去除效果,去除率可达到85%以上,且在单个SBR运行周期中的去除趋势一致;两个SBR的活性污泥EPS中多糖和蛋白质无显著差异,以SA为共代谢碳源降解4-CP的活性污泥更易分泌胞外蛋白质。     

对乙酰氨基酚制备过程中废水的处理

采用芬顿法、光催化氧化法与生物降解法相结合,研究对乙酰氨基酚制备过程中高浓度废水的降解。以COD的去除率为指标,研究各种方法的主要因素对废水降解效果的影响,通过控制单因素变量实验,确定各种方法的最佳工艺条件。结果表明,芬顿法的最佳工艺条件:废水的pH为4.0、FeSO4·7H2O加入量为0.10 mol/L、H2O2(30%)加入量为56.5 mL/L、反应时间3 h;光催化氧化降解废水的最佳条件:H2O2(30%)加入量4.5 mL/L,光照时间4 h。生物降解较适宜条件:pH为7.0,温度为28~29℃。在各种方法的最佳条件下,可使废水的COD从18 979.24 mg/L降至36.14 mg/L。     

紫外辐射加速磺胺嘧啶生物降解的机理

采用紫外光解与生物降解耦合的方法可以明显提高磺胺嘧啶(SD)的生物降解速率。经过分析,发现SD在紫外光解过程中首先生成对氨基苯磺酸(p-aminobenzenesulfonic acid,ABS)和2-氨基嘧啶(2-aminopyrimidine,2-AP),而ABS很快分解为苯胺(aniline,An)和SO2-4。其中2-AP不能加速苯胺的生物降解,反而具有一定的生物抑制。而苯胺可以提高其生物降解速率。按比例同时将2-AP和An加入到SD溶液中,其生物降解速率与紫外光解耦合生物降解时相近,是单独生物降解速率的2倍。这是因为苯胺在生物氧化过程中,可以提供足够的电子并通过共基质作用加速SD的初始单加氧反应。     

共代谢条件下丁基黄药的生物降解实验研究

微生物共代谢是降解废水中难降解有机物的重要方式。通过实验研究,比较了以丁基黄药作为唯一碳源和能源以及有共代谢基质存在下丁基黄药的降解过程。结果表明,共代谢显著提高了丁基黄药的降解率。在25℃条件下,以丁基黄药为唯一碳源和能源时,其降解率仅为43.1%;而利用葡萄糖作为共代谢基质,当葡萄糖质量浓度为0.20g/L时,振荡培养72h后丁基黄药的降解率可达65.2%;再加入微量的蛋白胨作为氮源后,丁基黄药的降解率可提高到73.5%;加入共代谢基质后微生物的适应期由原来的36h缩短至24h。共代谢是提高丁基黄药生物降解性能的一条有效途径。     

以有机酸为共基质硝基酚厌氧生物降解性研究

在中温厌氧消化条件下 ,以有机酸 (乙酸与丙酸的混合酸 )为共基质 ,通过测定甲烷累积产量 ,研究了 2 硝基酚、2 ,4 二硝基酚的厌氧生物降解性。试验条件为 :温度 35℃ ,COD 110 0～ 12 0 0mg/L ,pH 7 0～ 7 5 ,COD/VSS为 0 1,接种污泥未驯化 ,其产甲烷活性CH4/VSS为 195mL/g。研究结果表明 ,在所选的浓度范围内 (≤ 4 4mg/L) ,2 硝基酚对产甲烷过程没有产生抑制作用 ;2 ,4 二硝基酚是抑制性较强的物质 ,浓度为 12～ 2 0mg/L时产生中度抑制 ,大于 2 8mg/L时产生重度抑制     

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).     

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     

实验室质量管理体系内部审核的策划

在实施ISO／IEC 17025：1999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，识别出内部审核策划阶段的关键环节，提出审核范围确定、审核计划和抽样方案制订的质量控制要求，为有序高效地实施内部审核提供了技术方法。     

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.     

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。     

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.