基于生物沸石复合滤料的间歇式脱氮水处理

以粒径0.15～0.18 mm的天然沸石粉为主要原料,水泥为黏结剂,制备出粒径4～8 mm的沸石复合滤料（ZCF）.对制备的材料进行了空隙率、表观密度、强度等性能测试.优化出复合滤料中m（沸石粉）：m（水泥）=7：3,自然条件下养护15 d.利用该ZCF装填实验柱,完成硝化微生物挂膜培养,然后进行间歇式脱氮水处理动态实验,间歇式运行周期分为吸附、生物再生、淋洗共3个阶段.采用上流式进水吸附脱氮,以NH4＋-N浓度低于2 mg·L-1为出水标准,出水超标后,排空实验柱中水,鼓风生物再生,用水淋洗滤料后重复沸石吸附-生物再生循环,淋洗液单独进行反硝化处理.结果表明,在模拟实验条件下间歇式运行最佳的周期为：吸附5 d,鼓风生物再生24 h,NH4＋-N平均去除率为87.7%,TN平均去除率达51.2%.     

Fugitive Gas Emissions from Fuel Tanks

Many fuel installations and industrial operations often are associated with the release, whether deliberately or inadvertently, of fuel vapors into the surrounding atmosphere. Most of these releases may be considered to be relatively small on a thermal basis, but they do represent collectively a serious source of unburned hydrocarbon emissions into the atmosphere. Moreover, the emissions of methane from various sources of natural gas contribute significantly to green house gas emissions.

The paper presents computed results of the transient dissipation of a fixed mass of methane when released within vertical cylindrical vessels containing air, which are open to the outside atmosphere under ambient conditions. Particular attention is given to the rates of emission of gas into the outside atmosphere and how it is affected by the composition and mass of the fuel released and the size and configuration of the fuel retaining cylindrical tank. The corresponding transient formation, growth and subsidence of flammable zones within such a vessel are also described. Some guidelines for reducing the hazards associated with such releases are presented.     

水环境容量一维计算中不均匀系数研究

文章介绍传统地表水环境容量一维计算方法,针对其缺陷提出考虑不均匀系数的计算方法。介绍混合区概念及其允许范围,应用二维水质模型求解不均匀系数,并分析其计算结果。作为实例,对广西红水河某河段水环境容量进行计算,取得了很好的效果。     

ABSBR反应器水力混合特性的研究

文章根据因次分析方法推导出ABSBR反应器水力混合特性的无因次准则,并对反应器水力混合特性进行了实验研究。     

中试MBBR反应器启动CANON工艺及其短程硝化

采用150 L的移动床生物膜(MBBR)反应器,控制温度为28℃,以无机高氨氮(平均浓度350 mg·L~(-1))废水为原水,启动全程自养脱氮(CANON)工艺,同时,取其中絮状污泥至5L的SBR反应器中,维持进水NH~+_4-N浓度为90～200 mg·L~(-1),共同进行短程硝化恢复研究.结果表明,MBBR反应器中,HRT平均为12 h时,短程硝化与TN去除率互相制约,TN去除率平均为38.2%,δNO~-_3-N/TN值平均为0.274,当HRT降至6h后,δNO~-_3-N/TN值由0.347下降至0.146; SBR反应器通过间歇曝气,分别维持曝气与停曝时间为30 min与20 min,好氧过程中DO浓度为0.5～0.6 mg·L~(-1),且每周期末FNA浓度高于0.18 mg·L~(-1)时, 12 d后系统内NAR由0增长至99.2%,NUR从24.8 mg·(g·h)~(-1)降至0,TN去除率则由13%降至3%,成功由全程硝化转变为短程硝化;高通量测序结果显示:MBBR反应器中Candidatus Kuenenia在絮状污泥和生物膜中的相对丰度分别为7.91%及17.38%,Nitrosomonas在二者中分别占27.43%和2.55%,Nitrospira则在二者中占0.30%和0.28%; SBR反应器恢复短程硝化后,AOB与ANAMMOX丰度分别下降至1.18%和0.01%,Nitrospira的相对丰度则上升至1.39%.     

高频间歇梯度曝气启动短程硝化反硝化除磷颗粒污泥

反硝化除磷与厌氧氨氧化耦合可进一步降低脱氮除磷所需的碳源,而稳定获取NO₂^--N是两工艺独立、联合运行的关键.因此,以低C/N生活污水为研究对象,接种絮状污泥及少量长期贮存的好氧颗粒污泥,采用两段梯度曝气,并控制停曝时间（3min：3min）,即以高频间歇梯度曝气模式,经60d的富集培养,将其诱导成具有短程硝化反硝化除磷功能的颗粒污泥,并分析了此过程中系统脱氮除磷性能变化.结果表明,稳定时期内,颗粒污泥平均粒径达841μm,SVI为31.23ml/g,颗粒结构致密,沉降性能良好.出水NO₃^--N小于0.1mg/L,TP<0.7mg/L,NO₂^--N>15mg/L,实现了P的高效去除和NO₃^--N的积累,并可为后续耦合Anammox提供稳定NO₂^--N基质.批次实验结果表明,颗粒中可利用NO₂^--N为电子受体的DPAOs占达57.63%,其富集提高了系统除磷能力.高频梯度间歇曝气可实现AOB与DPAOs的高度耦合,但仅以间歇曝气难以实现NOB的抑制,后通过在"氨谷点"前段,加入梯度曝气优化实际限氧曝气点,可强化对NOB的抑制,从而实现良好的亚硝酸盐积累.     

有机酸性工业废水铁曝气中和预处理探讨

对某有机有毒酸性工业混合废水,采用铁刨花曝气还原加中和絮凝沉淀法进行预处理研究,色度八方经达８５％以上,ＣＯＤ去除率达５０％,初步改善了混合污水的可生化性能,减轻了后续生化处理工艺的有机负荷。     

Sensitivity of the DERMA long-range Gaussian dispersion model to meteorological input and diffusion parameters

The Danish Emergency Response Model of the Atmosphere (DERMA) is described and applied to the first ETEX experiment. By using analysed low-resolution numerical weather-prediction data from the global model of the European Centre for Medium-range Weather Forecast (ECMWF) as well as higher-resolution data from two versions of the High Resolution Limited Area Model (HIRLAM), which are operational at the Danish Meteorological Institute (DMI), the sensitivity of DERMA to the resolution of meteorological data is analysed by comparing DERMA results with concentration measurements. Furthermore, the sensitivity to boundary-layer height and diffusion parameters is studied. These parameters include the critical bulk Richardson number, which is used to estimate the atmospheric boundary-layer height, the horizontal eddy diffusivity and the Lagrangian turbulence time scale. The parameters, which provide the best performance of DERMA, are 0.25 for the critical bulk Richardson number, 6×10³ m² s^-1 for the horizontal eddy diffusivity, and 3 h for the Lagrangian time scale. DERMA is much more sensitive to boundary-layer parameters when using high-resolution DMI-HIRLAM data than when using data of lower resolution from the ECMWF. Finally, the bulk Richardson number method of boundary-layer height calculation applied to DMI-HIRLAM data is verified directly against routine radiosondes released under the tracer gas plume. The boundary-layer height estimates based on analysed NWP model data agree well with observations, and the agreement deteriorates as a function of forecast length.     

粗粒沉积物对污水的净化能力试验研究

采用连续和间歇２种注入方式,对粗粒松散沉积物净化污水的能力进行了试验研究,结果表明,１．５ｍ厚的砂卵石层对污水中细菌,合成洗涤剂,总铬等污染物的净化率可达５０％以上,间歇注入试验对Ｍｎ（Ⅱ）的净化率可达７６．１５％,而连续注入试验２４．７％,污水在粗粒沉积物中的入渗属氧化条件,有利于硝化作用进行。     

生物流化床反应器水力混合特性研究

分别以活性炭和陶粒作为载体,在无回流条件下研究了不同上升流速时,反应器的离散数D/μL和串联数N的变化规律.试验结果表明,上升流速,固体混合特性以及载体性质均对反应器离散程度产生影响.只要反应器达到一定的膨胀率,反应器的流态就比较接近完全混合型.活性炭为载体时,上升流速为0.29cm/s,膨胀率为9.5％,串联数N为2.17.说明用完全混合型反应器模拟生物流化床反应器是可行的.