间歇式气水联合反冲洗生物炭池的试验研究

为合理控制生物炭池的反冲洗过程,改善其整体运行性能,试验以反冲洗出水浊度、反冲洗前后有机物的去除率和炭池的生物量、生物活性的变化等为评价指标,比较分析3种不同的气水联合反冲洗方式对生物炭池运行效果的影响.结果表明,间歇式气水联合反冲洗更适合于生物炭池,反冲洗后生物活性明显升高,比反冲洗前增加了62.5%;而气+水的反冲洗方式和气水混合+水冲的反冲洗方式的生物活性增加率为55.6%、38.5%.间歇式反冲洗308h后,反应器能恢复运行性能,UV254去除率达60.0%.反冲洗出水的类富里酸荧光峰很弱,而以低激发波长类色氨酸(峰S)和高激发波长类色氨酸(峰T)为主,这来源于被冲刷下来的微生物残片.三维荧光光谱也表明,间歇式气水联合反冲洗容易将微生物残片冲刷干净.     

综掘工作面气水联动除尘装置影响因素及应用效果分析

为掌握气水联动除尘装置影响因素及现场除尘效果,以便更好应用于现场实际。基于煤矿综掘工作面长压短抽通风控除尘系统,利用数值仿真和正交实验设计分析方法,系统研究除尘装置叶片参数、进风量和进风口位置等因素对除尘效果的影响规律。研究结果表明：叶片安装角为40°,扭转角为4°时,除尘器入口处负压值和进风量最大,而吸风口距工作面5 m、吸风量≥300 m³/min时的除尘效果较好。控除尘系统采用气水联动除尘装置后,各测点全尘除尘效率提高了40.8%～55.4%,呼吸性粉尘除尘效率提高了31.4%～41.3%,应用效果良好。     

膜生物反应器中膜污染控制方法的研究

从膜生物反应器的类型、气水比和粉末活性炭的投加浓度等方面研究了控制膜污染的方法。结果表明 ,最优的一体式和分置式膜生物反应器的类型是不同的 ;大的气水比有利于减轻膜的污染 ,但在一定的水质条件下 ,增大曝气量所引起的膜通量减少速度是有限的 ;投加适量的粉末活性炭 ,可减缓膜污染 ,但投量过大时 ,反而易造成膜堵塞     

铁锰泥除砷颗粒吸附剂对As(Ⅴ)的吸附去除

以除铁除锰生物滤池反冲洗泥为主要原料制备除砷颗粒吸附剂(granular adsorbents for arsenic removal,GA),使用SEM、XRD与BET等技术对其进行表征,并考察了GA对As(Ⅴ)的吸附机制和性能.结果表明,GA表面粗糙且孔隙发达;XRD图谱中出现石英晶体和少量赤铁矿晶体衍射峰,内部结晶度差;比表面积为43.8 m~2·g~(-1),存在大量介孔.吸附动力学过程符合准二级动力学模型.Freundlich等温方程更符合其吸附行为(R2=0.994).最大吸附容量为5.05 mg·g~(-1).进一步分析表明,在pH为1.1~9.5的范围内,GA对As(Ⅴ)具有较好的吸附效果.H_2PO_4~-与SiO_3~(2-)能显著抑制As(Ⅴ)的吸附,而HCO_3~-、SO_4~(2-)对吸附效果影响相对较小.GA的可再生性好,3次再生后吸附量相当于初始吸附量的82%.     

吴闵污水外排工程越江倒虹管泥沙模型的试验研究

针对上海市吴闵污水外排工程中越黄浦江倒虹管运行现状进行了泥沙淤、冲模拟试验 ,结果显示管内小流量情况下会存在严重淤积 ,必须调整运行安排。由此 ,笔者结合泵站实际运行能力提出了几点建议和措施 ,对吴闵污水外排工程管理部门具有一定的参考价值。     

膜污染及其防治措施研究

膜污染是膜生物反应器的主要问题,严重影响了废水处理的效果.膜生物反应器中膜污染的问题是不可避免的,并且有很多因素影响着膜污染.在充分研究膜污染的原因和特征的基础上,可以通过选择最优的膜生物反应器类型,对料液进行预处理以及优化膜分离的操作条件来预防污染的形成.另外,膜的定期清洗和再生也是减轻膜污染所不可缺少的.通过合理的防治措施可以有效的减轻膜污染,使膜技术不断进步和完善,以便使其在水处理技术方面得到更广泛的应用.     

Three-dimensional field studies of thermal backwashing plumes

Using specially designed temperature profiling equipment, two surveys were conducted during thermal backwashing operations at Pilgrim Nuclear Power Station to determine the spatial and temporal extent of temperature rises above ambient. Thermal backwashing is a process where biofouling is combated by a heat treatment procedure. Backwashing formed a thermal plume about 5- to 6-ft thick (1.5- to 1.8-m) in front of the intake screenwall. Maximum observed surface temperatures were 101.0°F (38.3°C), representing a rise (T) of about 43.4°F (24.1°C) above ambient. The frontal zone of the plume spread gradually seaward at about 0.2 kn. Its outer edge became thinner and rapidly cooled, presumably by advection and turbulent diffusion associated with currents from the reverse pumping and local changes from dissipation to the atmosphere. Along the intake shoreline, the plume was often less than 1 ft (0.3 m) thick. Most of the hot water was dissipated within several hundred feet of the intake with Ts of about 10.0 to 15.0°F (5.6 to 8.3°C) above ambient. Under the influence of 15 mph southwesterly winds during the second survey, some warmed water was apparently carried beyond the outer breakwaters into Cape Cod Bay. These surveys provided real-time data indicating that the backwashing operation caused a relatively thin thermal plume, which spread rapidly from the intake out across the study area and along the seaward breakwater. Within a few hours these backwash thermal plumes were completely dissipated.Formerly affiliated with Normandeau Associates, Inc., Bedford, New Hampshire.     

Experimental Study of Gas-Liquid Interfacial Properties in a Stepped Cascade Flow

Gas-liquid interface measurements were conducted in a strongly turbulent free-surface flow (i.e., stepped cascade). Local void fractions, bubble count rates, bubble size distributions and gas-liquid interface areas were measured simultaneously in the air-water flow region using resistivity probes. The results highlight the air-water mass transfer potential of a stepped cascade with measured specific interface area over 650 m^–1 and depth-average specific area up to 310 m^–1. A comparison between single-tip and double-tip resistivity probes suggests that simple robust single-tip probes may provide accurate, although conservative, gas-liquid interfacial properties. The latter device may be used in the field and in prototype plants. Notation a = specific interface area (m^–1); a _mean = depth-average specific interface area (m^–1): a _mean=frac1Y ₉₀limits sup> Y ₉₀ sup ₀(1–C)dy; C = local void fraction; C _gas = dissolved gas concentration (kg m^–3); C _mean = depth-average mean air concentration defined as: C _mean=1–d/Y ₉₀; C _s = saturation concentration (kg m^–3); D = dimensionless air bubble diffusivity (defined by [1]); d = equivalent clear-water flow depth (m): d=limits sup> Y ₉₀ sup ₀(1–C) dy; d_ab = air bubble diameter (m); d_c = critical flow depth (m); for a rectangular channel: d _c=sqrt[3]q _w ²/g; F = air bubble count rate (Hz); F _max = maximum bubble count rate (Hz), often observed for C=50%; g = gravity acceleration (m s^–2); h = step height (m); K _L = liquid film coefficient (m s^–1); K = integration constant defined as: K=tanh ^–1 sqrt0.1)+(2D)^–1 [1]; L = chute length (m); N = velocity distribution exponent; ———– ^*Corresponding author, E-mail: h.chanson@mailbox.uq.edu.au Q _w = water discharge (m³ s^–1); q _w = water discharge per unit width m² s^–1); t = time (s); V = local velocity (m s^–1); V _c = critical flow velocity (m s^–1); for a rectangular channel: V _c=sqrt[3]q _w g V _max = maximum air-water velocity (m s^–1); V ₉₀ = characteristic air-water velocity (m s^–1) where C = 90%; W = channel width (m); x = longitudinal distance (m) measured along the flow direction (i.e., parallel to the pseudo-bottom formed by the step edges); y = distance (m) normal to the pseudo-bottom formed by the step edges; Y₉₀ = characteristic distance (m) where C=0.90; Y ₉₈ = characteristic distance (m) where C=0.98; = slope of pseudo-bottom by the step edges; = diameter (m).     

搅拌式多介质过滤器在三元复合驱采出水处理中应用

三元复合驱采出水粘度高导致现有过滤器滤料板结,形成致密滤饼层,滤料无法彻底清洗,严重影响了过滤效果,出水水质难以达标。鉴于此,本项目开发了适合于高粘度废水处理用过滤器,通过采用桨式搅拌装置破坏滤料表层滤饼层,提高反冲洗效果,实现滤料彻底反冲洗。在大庆油田杏二中污水处理站采用该技术新建两座滤罐,研究了两级过滤处理效果。新建滤罐反冲洗压力维持0.2 mpa以内,水量稳定在400 m^3/h以上,解决了滤罐反冲洗憋压、跑料、滤料清洗不彻底问题,保证滤料彻底再生,提高了过滤效果,经二级过滤后出水油痕量,悬浮物在20 mg/L以下,达到油田污水回注标准。     

反冲洗周期对生物除锰滤池去除效果的影响

反冲洗周期是生物除铁除锰滤池的一个重要运行参数,实验中分别设定反冲洗周期为24、48和72h,考察反冲洗周期对成熟稳定运行的滤柱出水铁、锰、氨氮和浊度的影响。结果表明,不同反冲洗周期,滤柱对铁、锰和氨氮均有很好的去除效果,出水中的总Fe、Mn“和NH？-N的平均浓度分别为0．018、0．003和0．016mg／L,0．010、0．001和0．014mg/L,0．013、0．001和0．014mg／L,均远低于国家标准,说明反冲洗周期变化对三者的去除效果没有影响。反冲洗周期为24、48和72h时,出水平均浊度分别为0．27、0．38和0．57NTU,反冲洗周期越长,出水浊度越高。滤柱沿程浊度分析发现,浊度主要在0～O．4m去除,出水浊度与滤层厚度无关。反冲洗后5rain出水浊度为3．16NTU,15min降到了1NTU以下,25min降到了0．5NTU,60min大约降到了反冲洗前的水平。