HRT对固定床厌氧反应器运行效果的影响

为了考察水力停留时间(HRT)对炭纤维载体固定床厌氧反应器运行效果的影响,在进水COD分别为20 000~25 000 mg/L和40 000~45 000 mg/L2个浓度范围下,研究了不同HRT对反应器运行效果的影响。结果表明,通过HRT的调整,在达到相同有机负荷(OLR)下,进水COD为20 000~25 000 mg/L的COD去除率和产气量,明显比进水COD为40 000~45 000 mg/L的运行效果好;进水COD为20 000~25 000 mg/L,HRT为14 h,相应的OLR为41.09 kgCOD/(m3.d)时,COD去除率仍然维持在68%以上,沼气容积产气率达到14.55 m3/(m3.d)。炭纤维载体固定床厌氧反应器具有较高的COD去除率、产气效率以及抵抗低pH、高负荷冲击的能力,运行过程中没有发生反应器堵塞的现象。     

3,4,5-三甲氧基苯甲醛生产废水的厌氧可生化性及UASB处理

为了能经济有效地处理山东某一化工厂的3,4,5-三甲氧基苯甲醛生产废水,首先采用间歇式实验对车间生产废水进行厌氧可生化性评价。然后以此为基础,采用单级中温UASB,用二沉池的污泥为接种污泥,保持水力停留时间(HRT)不变,通过逐步提高进水COD的方式,考察在COD容积负荷(OLR)从1.0 g·(L·d)~(-1)逐步升高至10.0 g·(L·d)~(-1)的情况下,反应器处理效果的变化。在140 d的连续实验过程中发现,最优的OLR在6.0 g·(L·d)~(-1)(进水COD6 000 mg·L~(-1)左右),COD去除率能稳定在60.3%,出水pH值稳定在7.4到8.0之间,VFA在500 mg·L~(-1)左右。实验结果表明,UASB处理该制药厂废水是可行的。     

UASB处理硫酸盐有机废水的启动

为了考察上流式厌氧污泥床反应器(UASB)处理含硫酸盐有机废水的特性,采用有效容积为10 L的UASB,研究了启动运行过程中COD和SO2-4降解情况、出水VFA和pH值、产气量及颗粒污泥比产甲烷活性(SMA)变化状况。结果表明,接种厌氧颗粒污泥,保持进水COD为1 500 mg/L,SO2-4浓度为100 mg/L,将HRT由24 h缩短至12 h以提高负荷,经历55 d成功启动了UASB反应器;当HRT为12 h,进水COD和SO2-4负荷为3.0 kg/(m3·d)和0.20 kg/(m3·d),COD和SO2-4的去除率分别达到80%和89%,出水VFA为3 mmol/L,产气量达9.5 L/d,颗粒污泥的SMA为86.4 mL/(g VSS·d)。     

微电场-零价铁-UBF提高有机硫对位酯生产废水同步产甲烷反硝化效能

有机硫化合物对位酯生产废水具有COD高、含硫酸盐和有机硫高以及碳硫比低的特点,针对单一厌氧反应器在处理废水时只能在较低COD容积负荷(OLR)下运行的问题,在提高有机硫对位脂生产废水产甲烷反硝化效能的基础上,采用微电场-零价铁联合方式处理该类废水。实验结果表明:OLR(以COD计)为6.67 g·(L·d)-1,进水COD为20 000 mg·L-1时,复合床的COD去除率为70%,产甲烷率为1.41 L·(L·d)-1,反硝化率为87%,对位脂降解率为74%;在COD/TSO24-(总硫酸盐)为1.57时,COD去除率、产甲烷率和反硝化率可分别能稳定在60%、 1.18 L·(L·d)-1和79%;在COD/TSO24-为0.88时,产甲烷菌受到中等程度的抑制;当COD/TSO24-恢复为1.57时,厌氧系统在7 d后恢复,说明联合系统有很强的恢复能力。综合上述结果,与单一的UBF处理相比,采用微电场-零价铁能显著提高UBF的运行负荷和同步产甲烷反硝化能力,同时也能使反应器承受更低的碳硫比。     

UASB启动及不同HRT对老龄垃圾渗滤液处理效果的影响

在UASB反应器中接种好氧污泥培养厌氧颗粒污泥进行启动,研究不同HRT对老龄(13年)垃圾渗滤液对处理效果的影响情况。通过保持进水COD浓度不变、逐步缩短HRT从而提高容积负荷到40 g COD/(L.d)的方法,可以培育出直径为1～3 mm颗粒污泥,最终产气量稳定在100 L/d,甲烷含量在60%～70%之间,COD去除率保持在90%左右,污泥层最底部MLSS为81 g/L。逐步提高HRT依次为6、12、24、48和72 h考察其对处理效果的影响,当HRT为24 h时处理效果最好,COD去除率最高达到35%左右。     

有机负荷影响好氧颗粒污泥特性的研究

好氧颗粒污泥形成后,逐步提高进水有机负荷(OLR)至好氧颗粒污泥解体,分析OLR对系统运行特性、污泥表面特性及胞外蛋白和多糖的影响.进水OLR在4～8 g/(L·d)、污泥负荷(SLR)稳定在0.42～0.77 g/(g·d)、污泥龄为17.8～60.0 d时,好氧颗粒污泥系统处于最优运行阶段.好氧颗粒污泥形成后,随着进水OLR的提高,十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)能够直观地反映出胞外蛋白分泌量逐渐减少,而多糖分泌量呈相反趋势,导致蛋白/多糖(PN/PS,质量比)值从4.8降至0.9左右.当进水OLR从4 g/(L·d)增至12 g/(L·d)时,污泥表面相对疏水性从75.8%降至38.5%,这可能与胞外蛋白分泌量减少及多糖分泌量增加有关.PN/PS值的降低可能是好氧颗粒污泥在高OLR下解体的内在原因.因此,微生物分泌的胞外多聚物(EPS)中较高的PN/PS值利于好氧颗粒污泥的长期稳定运行.     

EGSB反应器处理城市生活垃圾沥滤液

采用膨胀颗粒污泥床(EGSB)反应器对城市生活垃圾焚烧厂产生的垃圾沥滤液进行处理。实验结果表明:中温条件下,当COD浓度为55 000 mg/L左右,有机容积负荷(OLR)为22.8 kg COD/(m3.d)时,EGSB对垃圾沥滤液具有较好的的处理效果,COD去除率可达94.2%。当进水COD为72 000 mg/L左右时,为保证反应器的稳定运行,OLR应降低至18.2 kg COD/(m3.d),此时COD去除率可以达到88%左右,出水COD平均为9 103 mg/L。垃圾沥滤液和EGSB处理出水均以小分子量有机物为主,其中<4 kDa的有机物分别占76.5%和74.4%。EGSB对整个分子量区间的溶解性有机物都有较好的处理效果,其中对大分子有机物的处理效率相对更高。     

厌氧折流板反应器处理化纤厂棉浆粕综合废水的实验研究

对新型厌氧反应器(ABR)处理化纤厂棉浆粕综合废水进行了研究。试验结果表明:采用ABR厌氧处理该废水,可以有效去除其中的有机物,在HRT为1d、进水COD为3360mg/L、有机负荷(OLR)为3.36kgCOD/(m3·d)的条件下,COD去除率为71.5%,出水COD降至958mg/L;利用浆粕黑液和纺丝废水混合调节pH,可以减少碱的用量,降低运行成本。     

UASB启动及不同浓度垃圾渗滤液的处理效果

在UASB反应器中接种好氧污泥培养厌氧颗粒污泥进行启动,研究不同浓度老龄(13年)垃圾渗滤液对处理效果的影响情况。通过保持进水COD浓度不变、逐步缩短HRT从而提高容积负荷到20 g COD/(L.d)的方法,可以培育出直径为1～3 mm颗粒污泥,最终产气量稳定在60～70 L/d,甲烷含量在50%～70%之间,COD去除率保持在90%左右,污泥层最底部MLSS为50 g/L。逐步提高进水中渗滤液的含量考察其对处理效果的影响,当进水为100%渗滤液时日产气量为500 mL/d、COD去除率仅为10%,表明渗滤液中多为难降解性有机物质。     

BLR厌氧反应器处理垃圾焚烧厂渗滤液工程运行效能

采用1 100 m3BLR(biogas-lift reactor)厌氧反应器对垃圾焚烧厂渗滤液进行工程化处置,接种污泥为消化污泥,正常运行温度控制在(33±2)℃,启动负荷为1 kg COD/(m3·d),120 d后容积负荷达到10 kg/(m3·d)并稳定运行,出水COD浓度为4 500~6 500 mg/L,COD去除率为88%~92%,出水VFA含量为200~600 mg/L,p H值稳定在7.4~7.7,出水SS含量为1 000 mg/L左右,并可观察到沉降性较好的颗粒化污泥。反应器运行初期将VFA/ALK控制在1.6以内,系统并未因VFA积累而酸化崩溃,运行后期VFA/ALK值小于0.3,系统稳定运行。运行过程中进水氨氮浓度从400 mg/L升高到2 200 mg/L,未发现氨氮对厌氧生物处理的明显抑制现象。垃圾渗滤液中平均每去除1 kg COD产生沼气量为0.32 m3。     

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.