微量NO2对厌氧氨氧化甲烷化反硝化耦合影响的动力学分析

采用批试验方法,研究微量 NO2对颗粒污泥厌氧氨氧化、甲烷化和反硝化耦合的影响.基于 Haldane 模型建立了厌氧氨氧化的 NO2 强化函数,估计了强化函数中的最大强化系数(30.55)、NO2 半饱和常数(1.96 mg/L)、NO2 抑制常数(0.0082 mg/L)和基础速率系数(0.0314).微量 NO2 对甲烷化和反硝化动力学可用反竞争性抑制动力学方程进行描述.甲烷化的最大比乙酸盐去除速率为0.15 mg COD/(mg VSS·h),乙酸盐半饱和常数为395 mg COD/L,NOz抑制系数为0.623 mg/L.反硝化的亚硝酸盐氮最大去除速率 0.00685 h-1,亚硝酸盐氮半饱和常数0.214 mg/L,NO2 抑制系数为22.4 mg/L.试验中大部分的 NOx 气体物质出现损失.     

C/N比对ANAMMOX与反硝化协同脱氮性能影响及其动力学

采用ASBR厌氧氨氧化(ANAMMOX)反应器,考察了不同C/N(NH+4-N)比时厌氧氨氧化与反硝化协同脱氮性能表现,并与无机环境下反应器的脱氮性能相比较。研究结果表明,C/N比决定了ANAMMOX/反硝化耦合反应的发展方向。当C/N0.33时,ANAMMOX为主导反应;当C/N=0.67时,耦合反应的效果最佳,NH_4~+-N和NO_2~--N的去除率分别为92%、95%、COD去除率大于96%,实现了氨氮及COD的同时去除;当C/N=1.33时,反硝化反应逐渐占据优势;当C/N2.96时,反硝化作用成为主导反应,厌氧氨氧化反应受到明显抑制,氨氮去除率下降。采取批次实验方法研究了厌氧氨氧化与反硝化协同反应的动力学特性。用基质抑制动力学Haldane模型拟合不同基质浓度下的厌氧氨氧化活性,得到氨氮最大比增长速率为0.09 kg/(kg·d)(以VSS计),半饱和常数为8.4 mg/L、半抑制常数为1 198.2 mg/L;亚硝态氮最大比增长速率为0.27 kg/(kg·d)(以VSS计),半饱和常数为10.2 mg/L、半抑制常数为300.1 mg/L。采用Monod模型和Haldane模型分别拟合不同COD浓度和亚硝酸盐浓度下的反硝化性能,得到反硝化亚硝态氮最大比增长速率为0.2 kg/(kg VSS·d),半饱和常数为17.4 mg/L、半抑制常数为128.4 mg/L,COD半饱和常数为83.3 mg/L。     

CAST工艺常规模式下脱氮性能研究

研究了有效容积为21.6 L的循环式活性污泥法反应器在常规模式下,处理模拟废水时,有机污染物和氮污染物的去除情况,并分析了反应器脱氮过程中的限制性因素。结果表明,在反应器的运行周期为4 h(进水曝气2 h,沉淀和排水各1 h)好氧区DO2 mg/L,污泥浓度MLSS稳定在4 000 mg/L时,污泥回流比为20%,COD和氨氮的去除率可达90%。对一个典型周期进行监测分析,氨氮去除彻底,出水主要是硝态氮,总氮去除率约为69%。静态试验测得氨氮氧化速率为8.0 mg NH4+-N/(g MLSS.h),硝态氮生成速率为3.3 mg NO3--N/(g MLSS.h)。从实验结果可以分析出,在上面运行条件下CAST工艺脱氮限制性因素是回流比和污泥龄。     

某污水处理厂A2/O工艺冬季生物反硝化过程的影响因素研究

针对污水处理厂冬季反硝化脱氮效率不佳的问题,以常州市某污水处理厂A~2/O工艺为研究对象,模拟探讨了不同外加碳源、碳源投加量、溶解氧(DO)和硝态氮浓度对生物处理系统反硝化脱氮能力的影响。结果表明,外加有机碳源对系统的反硝化效能有明显的强化效果。3种外加有机碳源(乙酸、乙醇和乙酸钠)中,乙酸为最佳碳源。当乙酸投加量为40mg/L时,系统反硝化脱氮效率最高,比反硝化速率可达1.964mg/(g·h),反硝化碳耗最少,为7.14 mg/mg。DO与比反硝化速率成反比,DO≤0.20mg/L时,反硝化能力最强。硝态氮初始质量浓度为20mg/L左右时,反硝化能力最强。在实际工程应用中,可以通过提高硝化效果或直接调整回流比实现反硝化脱氮最优条件,将有助于提高系统的冬季脱氮效果。     

微量NO2对厌氧氨氧化甲烷化反硝化耦合影响的动力学分析

采用批试验方法,研究微量NO₂对颗粒污泥厌氧氨氧化、甲烷化和反硝化耦合的影响。基于Haldane模型建立了厌氧氨氧化的NO₂强化函数,估计了强化函数中的最大强化系数（30.55）、NO₂半饱和常数（1.96 mg/L）、NO₂抑制常数（0.0082 mg/L）和基础速率系数（0.0314）。微量NO₂对甲烷化和反硝化动力学可用反竞争性抑制动力学方程进行描述。甲烷化的最大比乙酸盐去除速率为0.15 mg COD/（mg VSS·h）,乙酸盐半饱和常数为395 mg COD/L,NO₂抑制系数为0.623 mg/L。反硝化的亚硝酸盐氮最大去除速率0.00685 h^-1,亚硝酸盐氮半饱和常数 0.214 mg/L,NO₂抑制系数为22.4 mg/L。试验中大部分的NOx气体物质出现损失。     

MFC强化同步短程硝化反硝化工艺的启动

微生物燃料电池(MFC)可在阴极实现反硝化、短程反硝化和同步硝化反硝化并产生电能,但在MFC阴极实现同步短程硝化反硝化的研究尚未见到报道。为了探讨MFC阴极同步短程硝化反硝化工艺的性能,将双室曝气阴极MFC与A/O脱氮工艺结合处理人工模拟低碳氮比废水。通过静置运行15 d使得MFC阴极室亚硝态氮得以积累,氨氧化菌得以富集。随即改为连续运行后第21天成功启动同步短程硝化反硝化MFC;阴极出水氨氮浓度为0.3 mg/L,亚硝态氮浓度为15.9 mg/L,硝态氮浓度为0.6 mg/L,亚硝化率达到95%以上,阴极电极自养反硝化去除率达到50%以上,COD去除率达到85%以上。结果表明,将MFC与同步短程硝化反硝化工艺结合,通过阴极室中氧气得电子获得高p H,可以强化同步短程硝化反硝化工艺,完成生物脱氮的同时回收电能,并具有减少外加碱度的优势。     

短程反硝化聚磷的反硝化特征研究

研究了温度、pH值、电子供体种类及电子受体种类对反硝化的影响.试验结果表明,(1)在相同试验条件下,亚硝酸型反硝化与硝酸型反硝化的速率与硝态氮的浓度有关.在温度为25℃、pH为7的条件下,基质浓度＜300mg/L时短程反硝化速率较快;基质浓度≥300 mg/L时,以NO3-为基质的反硝化速率较大.(2)具有大量碳源储存物(PHB)的细菌可实现快速的内源性反硝化脱氮,而处于饥饿状态的细菌的内源性反硝化效率极低.     

游离和聚乙烯醇包埋门多萨假单胞菌好氧反硝化脱氮的研究

以从采自温州西片污水处理厂的活性污泥样品中分离的好氧反硝化门多萨假单胞菌(Pseudmonas mendocina)WZUF20为受试对象,以聚乙烯醇(PVA)-海藻酸钙-活性炭包埋固定化,研究游离和固定化细胞在人工硝态氮污水中好氧反硝化去除硝态氮的条件,以及它们对人工氨氮、硝态氮和亚硝态氮污水的氨氮、硝态氮和亚硝态氮的去除能力。结果表明:(1)游离细胞和固定化细胞去除硝态氮的适宜条件是相似的,适宜碳源为丁二酸钠、乙酸钠和柠檬酸钠,适宜碳源和KNO3质量比为10∶1,适宜温度、转速和pH分别为20~35℃、100~200r/min和6.0~9.5;(2)在适宜条件下,游离细胞和固定化细胞对人工氨氮污水氨氮的去除速率分别为8.79、1.67mg/(L·h),对人工硝态氮污水硝态氮的去除速率分别为8.17、4.54mg/(L·h),对人工亚硝态氮污水亚硝态氮的去除速率分别为16.42、7.67mg/(L·h);(3)在人工硝态氮污水中连续5批次的去硝态氮试验表明,PVA-海藻酸钙-活性炭固定化细胞是稳定的。说明门多萨假单胞菌(Pseudmonas mendocina)WZUF20以及PVA-海藻酸钙-活性炭包埋制备的固定化细胞具有应用于实际废水脱氮的潜力。     

不同DO下亚硝态氮氧化菌硝化系统N 2O减量化研究

采用序批式活性污泥反应器(SBR),在富集亚硝态氮氧化菌(NOB)的基础上,考察了DO对连续进水模式下硝化过程中N_2O减量化的影响。结果表明,在污泥氨氧化菌(AOB)和NOB的比耗氧速率(SOUR)分别为(2.36±0.31)、(7.62±0.43)mg/(L·h)条件下,不外加碳源进行小试实验,氨氮均小于1.0mg/L,亚硝态氮均小于0.5mg/L。DO由0.2mg/L增至3.0mg/L过程中,随着DO增加,积累的硝态氮浓度逐渐上升,而累计产生的N_2O浓度先上升后下降。DO为0.2mg/L时,积累的硝态氮和累计产生的N_2O浓度最低,可以实现N_2O的最大减量化。在进水连续投加氨氮的方式下,氨氮氧化速率不是引起N_2O生成的关键步骤,碳源缺乏的情况下NOB硝化系统中低DO可以有效控制N_2O的释放。     

温度和pH值对活性污泥法脱氮除磷的影响

温度和pH值是影响污水脱氮除磷效果的2个重要因素.试验采用连续搅拌槽式反应器(continuous stirred tank reactor,CSTR),通过对不同温度和pH值条件下的硝化、反硝化、释磷和吸磷反应速率的测定,总结出温度和pH值对活性污泥生化反应速率的影响规律.试验表明,硝化和反硝化速率随温度的升高而加快.在5℃和33℃时,硝化速率分别为0.01 kg NH4 -N/(kg VSS·d)和0.28 kg NH4 -N/(kg VSS·d);在5℃和30℃时,反硝化速率分别为0.097 kg NO3--N/(kg VSS·d)和0.476 kg NO3--N/(kg VSS·d);但温度对吸磷和释磷速率的影响不大.pH值对硝化、反硝化、吸磷和释磷速率均有显著影响,在pH值为7.74时,硝化速率为0.095 kg NO3--N/(kg VSS·d);而在pH值为4.9和10.08时,硝化速率仅为0.005 kg NO3--N/(kg VSS·d)和0.006 kg NO3--N/(kg VSS·d).在pH值为7.85时,反硝化速率达到最大值0.36 kg NO3--N/(kg VSS·d);而在偏酸性和碱性条件下,反硝化速率显著下降.     

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).     

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。     

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。     

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     

有机官能团对改性硅吸附微囊藻毒素的影响

考察了不同有机改性硅对微囊藻毒素LR(mLR)和LA(mLA)的等温吸附行为。结果表明,有机改性硅可有效吸附去除水体中<0.1×10-6(质量分数)的微囊藻毒素,并且吸附去除效果随表面改性官能团中碳原子数量的增加而增加;相同条件下,有机改性硅在微囊藻毒素异构体之间存在着一定的吸附选择性。     

生物质快速热裂解主要参数对生物油产率的影响

以松木木屑为原料,在自制的小型流化床上,开展了生物质热裂解温度、生物质粒径和进料速率对生物油产率的影响实验研究.结果表明,在热裂解温度分别为450、475、500、525和550℃条件下,当热裂解温度为500℃时,生物油产率最高,平均产率达到53.33%(质量百分比).反应温度越高,炭产量越低,不可冷凝气体产量越高,气体发热值越高;粒径＜1 mm的生物质其粒径对生物油产率影响不大;生物质进料速率增加时,生物油产率增加.本研究为生物能的利用提供了新的途径.