表面活性剂对填料曝气塔充氧性能的影响

针对废水中表面活性剂对曝气充氧能力的影响,研究了4种生物填料在表面活性剂存在的三相流环境中的传氧效果.结果表明,十二烷基苯磺酸钠(SDBS)显著降低了传氧系数KLa(20),且在7×10-5mol/L浓度附近KLa(20)最低.而十六烷基三甲基溴化铵(CTAB) 在3.5×10-5~8.1×10-4mol/L浓度区间却提高了曝气塔的传质系数KLa(20).对比分析了生物粒状填料存在对充氧性能的影响,发现填料对传氧系数KLa(20)均有提高,海绵填料相比清水环境对体系KLa(20)提高了约1倍.研究认为,离子型表面活性剂分子的双电层结构以及液相表面张力对传质效果有影响,生物填料也是提高曝气过程传氧的方法之一.     

采用花岗岩水膜除尘器燃煤锅炉脱硫和除尘的工艺改造

为了使现有花岗岩水膜除尘器的燃煤锅炉烟气净化达标排放,在不更换水膜除尘器的前提下,探讨和比较了后继烟气吸收装置喷淋塔和鼓泡塔的脱硫和除尘机理,提出改进措施。该技术具有工艺流程简单,建设和运行成本低,适用于由于历史原因仍有相当大数量使用的花岗岩水膜除尘器的烟气净化工艺路线的改造。     

Aerosol Generation by Bubble Collapse at Ocean Surfaces

Sea salt particles are part ofmarine aerosols in the troposphere. A fraction ofthese particles is released by droplets generatedduring the bursting of bubbles at the ocean surface.Droplets result from fragmentation of film caps (filmdroplets) and the disintegration of water jets formedsubsequent to the bubble collapse (jet droplets).This release process is also of importance fortechnical applications and, consequently, simulationtools have been developed, which now may be used toquantify the contribution of these effects to marineaerosol generation. To calculate the amount of filmdroplets generated, it is necessary to determine thevolume of the film cap, which is a function of itsthickness and surface area. While surface areas ofsmall bubbles can be determined by an analyticalsolution of a simplified balance of forces, shapes oflarge non-spherical bubbles are calculatednumerically. The determination of the film thicknessis based on a resonance model for bubbleoscillations. For a detailed analysis of the jetdroplet generation, the bubble burst induced jetformation and disintegration is simulated numericallyusing a SOLA-MAC algorithm.     

Turbulent air–water flows in hydraulic structures: dynamic similarity and scale effects

In hydraulic structures, free-surface aeration is commonly observed: i.e., the white waters. The air bubble entrainment may be localised (hydraulic jumps, plunging jets) or continuous along an interface (water jets, chutes). Despite recent advances, there are some basic concerns about the extrapolation of laboratory results to large size prototype structures. Herein the basic air bubble entrainment processes are reviewed and the relevant dynamic similarities are discussed. Traditionally, physical studies are conducted using a Froude similitude which implies drastically smaller laboratory Reynolds numbers than in the corresponding prototype flows. Basic dimensional analyses are developed for both singular and interfacial aeration processes. The results are discussed in the light of systematic investigations and they show that the notion of scale effects is closely linked with the selection of relevant characteristic air–water flow properties. Recent studies of local air–water flow properties highlight that turbulence levels, entrained bubble sizes and interfacial areas are improperly scaled based upon a Froude similitude even in large-size models operating with the so defined Reynolds numbers ρ _w × q _w/μ _w up to 5 E+5. In laboratory models, the dimensionless turbulence levels, air–water interfacial areas and mass transfer rates are drastically underestimated.     

孔径对微孔曝气充氧性能的影响

孔径是微孔曝气产品最重要的参数之一,研究孔径对微孔曝气氧传质的影响对于提高微孔曝气器充氧性能有重要意义。本研究在1.5 m水深条件下对不同大小孔径的钟罩型塑料微孔曝气器充氧性能进行评价。结果发现,在实验条件下,微孔曝气器的阻力损失RL、标准氧总转移系数KLas、标准氧转移速率SOTR,标准氧转移效率SOTE及理论动力效率E随孔径增大而显著减小。     

微孔曝气变速氧化沟循环特性的中试研究

氧化沟工艺被广泛应用于脱氮除磷系统,其沟宽和流速均相等,这使得缺氧段和微孔曝气段因水流连续性均有相同的不沉降水平流速,造成曝气区流速高,推进能耗大。基于节能理念,为验证氧化沟变速的可行性,对中试变速氧化沟进行实际流速测定,结果表明,变速氧化沟在沟宽0.4 m处,其断面平均流速约为0.15 m/s;在沟宽1.2 m处,其断面平均流速约为0.07 m/s,上述2种沟宽实际流速比值与其对应的理论流速比3∶1相比较小,但该结论验证了氧化沟变速的可行性。另外,对沟内易沉降点不同水深处沉降比和SS分布进行测定,未出现较大的差值,结合长期工艺表面观察未发现泥水分离和泥块上浮现象。     

生物悬浮填料对微孔曝气氧传质影响的中试研究

生物填料在污水处理中常用来增加生物量以提高污水的净化效率,同时生物填料的加入会影响曝气氧转移效率.考察了典型的SPR-1生物悬浮填料在清水中对微孔曝气氧传质过程的影响.结果表明,在水深为6.00 m时,SPR-1生物悬浮填料有助于促进微孔曝气的氧传质,当填料填充率为40％,单位体积通气量为0.755 m3/h时,氧总转移系数(KL a20)和标准氧转移效率(SOTE)提高程度最大,分别为19.32％和5.78％;当水深为2.33 m时,SPR-1生物悬浮填料对微孔曝气氧传质有阻碍作用.在实际污水处理过程中,可以根据水深,调节填料填充率来使填料最大限度地促进氧传质.     

金属微孔管制造微气泡的研究

用金属微孔管制造微气泡是一种比较新颖的气泡制造方法.研究了由金属微孔管内外压差提供推动力,推动管内气体从管上的微孔流出,在管外壁形成微气泡,管外高速流过的剪切流把气泡带走,形成气液混合水的气泡制造方法.微气泡的大小和数量通过改变管内外的压差和管外剪切流速度来控制.实验结果表明,产生的微气泡直径在20～70μm之间变化,数密度在0.53×103～1.01×103个/mm3之间.     

阴离子表面活性剂对微孔曝气氧传质过程影响的研究

阴离子表面活性剂在污水中广泛存在,并对曝气氧传质过程有重要影响.因此,通过试验研究了不同浓度的十二烷基苯磺酸钠(SDBS)对微孔曝气氧传质过程的影响.结果表明,当表面活性剂SDBS的浓度在0～5.74×10-5mol·L-1之间变化时,氧总转移系数(KLa)和水质修正系数(α)先减小后增大,在浓度为1.43×10-5 mol· L-1左右时最低.对于同一SDBS浓度,通气量越大,α值越大,说明大气量可以部分抵消表面活性剂对传质的不利影响.在低表面活性剂浓度(CsDBs＜ 1.43×10-5 mol· L-1)时,表面张力迅速下降,抑制传质作用占主导,此时KLα减小;随着表面活性剂浓度增大,由于气含率增大所带来的促进传质作用逐渐占主导,此时KLa增大.最终建立KLα和表面张力(γ∞)、气含率(b)之间的多元线性关系方程为:KLα =0.00024γ∞+0.094 b+0.044.     

双灯纸业有限公司造纸废水生态治理工程零排放的研究

分析了造纸废水生态处理场降雨量、蒸发量和苇田蒸散量 ,以及实际耗水量和贮水量 ,结果表明 ,双灯纸业有限公司废水生态处理工程的零排放目标是现实可行的。