污水快速净化器处理低浓度生活污水的试验研究

采用污水快速净化器,以硫酸铝(AS)和聚合氯化铝(PAC)为混凝剂处理校园生活污水,研究其投加量与浊度和COD去除率之间的关系,确定出AS的最佳投加量为270mg·L-1,PAC的最佳投量为240mg·L-1,同时研究了最佳无机混凝剂AS与有机助凝剂PAM在废水处理中的协同作用,得出AS和PAM复合投加的最佳投加量为AS为150 mg·L-1,PAM为1 mg·L-1或AS为120mg·L-1,PAM为1.5 mg·L-1.PAC和PAM复合投加的最佳投加量为PAC为200mg·L-1,PAM为0.5 mg·L-1或PAC为120mg·L-1,PAM为1 mg·L-1,是最佳,最经济的组合方式.     

长江常州段微污染原水处理试验研究

针对长江常州段微污染原水的水质情况,通过烧杯试验确定了适宜的聚合氯化铝、活性炭和KMnO4投加量.结果表明,采用先投加KMnO4,再投加活性炭,最后添加混凝剂的工艺,对水中污染物的综合去除效率较高,其最佳投加量分别为KMnO4投加量为0.5mg·L-1,粉末活性炭投加量为40mg·L-1,聚合氯化铝投加量为10mg·L-1.     

污水处理厂出水的聚硅硫酸铝铁混凝除磷研究

研究新型混凝剂聚硅硫酸铝铁(PSFA)对城市污水处理厂出水中磷的混凝去除效果,考察了混凝剂投加量、原水pH、与聚丙烯酰胺(PAM)复配等因素对混凝除磷效果的影响,同时进行了聚合氯化铝(PAC)、聚合硫酸铁(PFS)和Al2(SO4)3混凝除磷效果的比较试验。结果表明,PSFA可有效降低城市污水处理厂出水TP含量,当投加量为36mg·L-1时,可以使出水TP的质量浓度从1.51mg·L-1下降到0.32mg·L-1,出水达到上海市地方标准DB31/199-2009规定的TP排放一级标准;PSFA混凝除磷适宜pH为6～10;PAM可以有效提高PSFA混凝除浊和除磷效果,减少混凝剂投加量;PSFA比PAC、PFS、Al2(SO4)3具有更好的混凝除磷效果,具有很好的应用前景。     

PAC对PDDA与一氯胺反应形成NDMA的影响

考察了聚合氯化铝(PAC)对聚二甲基二烯丙基氯化铵(PDDA)与一氯胺反应形成消毒副产物N-亚硝基二甲胺(NDMA)的影响。结果表明,在模拟微污染原水的氨氮含量条件下进行预氯氧化后,先加PAC后加PDDA、先加PDDA后加PAC、同时投加PAC和PDDA、投加PAC-PDDA这几种混凝剂投加方式测得NDMA生成质量浓度在30 ng/L左右,与未加PAC时生成NDMA的质量浓度22.80 ng/L相比,加入PAC后生成NDMA含量均稍有增加。各种投加方式下仅改变反应时间、温度、一氯胺或PDDA投加量与形成NDMA的量均不产生影响。在接近实际预氯氧化-复合混凝剂处理微污染原水的模式下,NDMA生成量与反应条件和投加PAC相关,但实质是受投加PAC引起体系pH改变的影响。     

不同强化混凝技术超滤工艺处理滦河水对比试验研究

通过小试与中试相结合,考察了用小试混凝沉淀技术代替中试混凝超滤工艺判断混凝剂最佳投药量的可行性,对比研究了经聚合氯化铝(PAC)、FeCl3、硫酸铝(AS)3种混凝剂预处理超滤后在除浊、除有机物、膜污染控制等方面的效能。结果表明,浊度的去除效果与混凝剂的种类和投加量无关,有机物的去除效果由高到低为PAC(45.5%)>FeCl3(42.4%)>AS(35.5%),膜污染程度(ΔTMP)由高到低为AS(42.72kPa)>FeCl3(39.68 kPa)>PAC(21.01kPa),综合比较采用PAC混凝预处理效果最佳,对水厂实际运行具有一定指导意义。     

壳聚糖类复凝聚胶体对高岭土悬浊液的混凝特性研究

采用壳聚糖-羧甲基纤维素钠(CS-CMC)、壳聚糖-海藻酸钠(CS-ALG)原位生成混凝剂,并通过烧杯实验研究其对高岭土悬浊液的混凝特性及机理。探究混凝剂投加量、水力条件、pH值、悬浊液浓度对混凝效果的影响。结果表明,高岭土悬浊液pH为5,CS-CMC投加量各20 mg/L时混凝效果达到最佳,沉降2 min后浊度去除率达到98.13%。高岭土悬浊液pH为4,CS-ALG投加量为CS投加10 mg/L、ALG投加20 mg/L时混凝效果达到最佳,沉降4 min后浊度去除率达到97.87%。CS-CMC、CS-ALG与PAC相比具有用量少、沉降时间短等优点。絮体Zeta电位测定、絮体粒径测定结果表明,两种混凝剂的主要作用机理为电性中和,同时存在网捕作用与吸附架桥作用。     

常州段长江原水强化混凝处理工艺的中试试验

为了提高长江常州段原水的混凝处理效果,采用不同混凝剂和助凝剂对长江水进行强化混凝现场中试试验。结果表明,聚合氯化铝(PAC)、聚合硫酸铁(PFS)和明矾这3种混凝剂中,PAC对长江水的混凝效果最好,形成絮体大,沉降性能好。PAC最佳投加量为30 mg/L,浑浊度去除率为84.6%,UV_(254)去除率达43.1%,COD和DOC去除率也较高,三维荧光强度显著降低。当聚丙烯酰胺投加量为0.09 mg/L时,可以兼顾助凝效果和经济性,浑浊度去除率达87.2%,UV_(254)去除率达46.9%,三维荧光强度进一步降低。研究优化了长江水的强化混凝运行工况,对于指导实际水厂运行具有较好的参考意义。     

磁铁砂加载絮凝技术处理低温低浊海水

采用磁铁砂加载絮凝技术处理低温低浊海水。通过混凝杯罐实验,研究探索了絮凝过程的最佳工艺参数,考察对比了磁铁砂加载絮凝与FeCl3混凝的处理效果。结果表明,混凝剂选用FeCl3、投加量为15 mg/L,磁铁砂粒径为75～125μm、投量为40 mg/L,以先投混凝剂、1 min后投加磁铁砂的顺序进行磁铁砂加载絮凝,可有效去除低温低浊海水中的SS、浊度和有机物。在混凝过程中,以磁铁砂为内核形成了紧密的磁性复合絮体,产生了电性中和、静电及磁场吸附作用,发挥了微砂加载絮凝和磁絮凝的双重优势。与FeCl3混凝相比,不仅处理效果提高,而且药耗减少、沉淀时间缩短、沉降絮体体积压缩,极具应用价值。     

PAC和PAM复合混凝剂对垃圾渗滤液预处理的研究

以某高含盐垃圾渗滤液为研究对象,通过投加混凝剂聚合氯化铝(PAC)和助凝剂聚丙烯酰胺(PAM)对其进行混凝沉淀预处理。单因素试验和正交试验结果表明,最佳混凝条件为PAC投加量为1 050 mg/L,PAM投加量为0.8 mg/L,PAM的投加时间在距离PAC投加之后7 min。在上述最佳处理条件下,原水COD由4 876 mg/L降至2 436 mg/L,COD去除率达50.04%。     

PDM复合混凝剂用于低温低浊水源水处理的研究——低浊度宁波姚江水处理

该文报道了用特征黏度系列化的有机阳离子高分子聚二甲基二烯丙基氯化铵(PDM)与无机混凝剂复合物对宁波低浊度姚江水的脱浊处理研究过程。通过混凝烧杯实验,考察了无机混凝剂的种类及其与PDM的复合配比对低浊度姚江水脱浊效果的影响。结果表明,对低浊度姚江水,要达到1.0~1.2 NTU的沉淀出水余浊,硫酸铝(AS)需5 mg/L左右的投加量,聚合硫酸铁(PFS)需8 mg/L左右的投加量,而聚合氯化铝(PAC)的投加量在10 mg/L左右;PDM对无机混凝剂强化混凝脱浊效果明显,无机混凝剂与PDM的复合配比越低,复合混凝剂混凝脱浊效果越好,在达到水厂沉淀出水浊度标准的前提下,AS/PDM复合药剂能比单独使用AS减少20%AS投加量;PFS/PDM复合药剂能比单独使用PFS减少30%~40%PFS投加量;PAC/PDM复合药剂能比单独使用PAC减少30%~50%PAC投加量。     

Evaluation of mixing conditions using an on-line monitoring technique

Effects of mixing conditions on flocculation were investigated by using a photometric dispersion analyzer (PDA) as an on-line monitoring technique in this study. Both river water and synthetic waters of humic acid (HA) and kaolin solutions were used and polyaluminum chloride (PACl) were used as a coagulant in this study. A clear relationship between F-index and residual turbidity was observed. Residual turbidity was low at high F-index. The mixing effects were also found closely related to the floc formation. When the floc formation was governed by a combination of charge neutralization and sweep floc, rapid mixing was important, but it was not important when the floc formation was governed by the sweep floc mechanism. The coagulant dosage governed the floc size and strength in the sweep floc region. The higher the coagulant dosage was, the larger but the weaker the floc was. Rapid mixing effects were different, depending on raw water characteristics. Fast and large floc formation was observed in flocculation of the kaolin solution, compared to that of the HA solution. Small HA would be mostly adsorbed onto the hydroxide precipitate after the precipitate formed. The adsorption could retard further floc growth. The resulting floc was small, and the floc formation was slow. However, kaolin helped flocculation by bridging the hydroxide precipitates, leading to fast and large floc formation. Temperature affected the flocculation kinetics as well as the floc size. A large floc formed at high temperature. The flocculation kinetics became fast with increasing temperature.     

Impact of Sludge Floc Size and Water Composition on Dewaterability

In order to observe the impact of different water compositions on sludge dewaterability, assessments of floc sizes using a particle size analyzer and of sludge dewaterability based on the capillary suction time (CST) test were carried out. Synthetic raw water had small floc sizes, and synthetic domestic wastewater had both larger median floc sizes and a better correlation between sludge dewaterability and median floc sizes. The floc size distribution results showed that synthetic raw water is associated with a narrow particle size distribution. In comparison, synthetic domestic wastewater produced a wider distribution. However, the CST values were similar for both waters. Compared to synthetic wastewater, natural wastewater had the largest distribution with generally larger particle sizes.     

Floc Formation,Size Distribution,and its Transformation Detected by Online Laser Particle Counter

Abstract

Coagulation and flocculation are widely applied in water and wastewater treatment. Removal of suspended particles is essential in water treatment and greatly depends upon the performance of the coagulant and the production of flocs with suitable properties. For monitoring floc size, formation, and size transformation, no particle size method now can be considered ideal. In this work an on‐line laser particle counter was used to follow coagulation with aluminum sulfate. The experiments showed that the floc formation and floc size distribution could be well monitored. The results showed that it is feasible to use particle counting for dosage control and for monitoring changes in floc formation, transformation and size distribution.     

Modeling spatial distribution of floc size in turbulent processes using the quadrature method of moment and computational fluid dynamics

A study was performed that utilizes the quadrature method of moments (QMOM) to model the transient spatial evolution of the floc size in a heterogeneous turbulent stirred reactor. The QMOM approach was combined with a commercial computational fluid dynamics (CFD) code (PHOENICS), which was used to simulate the turbulent flow and transport of these aggregates in the reactor. The CFD/QMOM model was applied to a 28 l square reactor containing an axial flow impeller and 100 mg/l concentration of 1 μm nominal clay particles. Simulations were performed for different average characteristic velocity gradients (40,70,90, and 150 s^-1). The average floc size and growth rate were compared with experimental measurements performed in the bulk region and the impeller discharge region. The CFD/QMOM results confirmed the experimentally measured spatial heterogeneity in the floc size and growth rate. In addition, the model predicts spatial variations in the aggregation and breakup rates. Finally, the model also predicts that the transport of flocs into the high shear impeller discharge zone was responsible for the transient evolution of the average floc size curve displaying a maximum before decreasing to a steady-state floc size.     

微污染水处理中混合液特性对膜污染的影响

重点研究了各工艺条件下的膜污染状况和混合液特性变化对膜阻力分布的影响。结果表明投加PAC和原水可生化性较好时都利于减缓膜污染。它们分别通过增加膜表面泥饼层的孔隙率和增大混合液的粗径分布来提高混合液可过滤性，使沉积层阻力Rc分别降至原MBR工艺的51．4％和33．3％。试验证实与原MBR工艺相比，投加PAC和采用可生化性较好的原水后，单位膜面积处理单位体积湖水时膜比通量的下降率分别由4．64％m^-1下降至1．85％m^-2和14．31％m^-1。     

高锰酸盐复合药剂预氧化处理松花江水的效果及机理

探讨了高锰酸盐复合药剂对春季时期松花江水的处理效果,采用流动电流检测技术研究了其电动特性,并用絮凝脉动颗粒检测技术对絮凝过程进行监测。试验结果表明,对于春季松花江水,单独投加混凝剂,不能有效去除浊度,投量过大还可能使浊度、色度等指标升高;投加高锰酸盐复合药剂对其进行强化处理后,可使沉后水浊度显著降低,对色度、CODMn也有较好的去除效果;投加高锰酸盐复合药剂使流动电流值SC升高,表明高锰酸盐复合药剂是通过氧化作用,降低了胶体颗粒表面负电性,使胶体稳定性降低,从而有利于混凝剂对胶体的絮凝作用;对絮凝过程的监测结果表明,高锰酸盐复合药剂强化了混凝过程,絮体形成快,絮体粒径大．     

磁加载絮凝处理含铜废水

目前磁加载絮凝技术已被研究用于处理多种类型的废水,然而关于此技术中磁粉作用机理方向少有报道。为了解决这一问题,本文采用磁加载絮凝法处理模拟微蚀铜废水,研究了磁粉的加入对Cu²⁺和浊度去除率、絮体沉降速率以及絮体粒径的影响,深入分析了磁粉的作用规律和机理,为磁加载絮凝法应用到实际工程中提供了理论依据和技术参数。结果表明,当磁粉投加量和粒径分别取2.0g/L和300～400目时,磁加载絮凝效果最好。此时,Cu²⁺和浊度去除率均达到最高值98.53%和94.72%,比传统絮凝法高出4.11%和0.61%;絮体沉降速率最快,达5cm/min,是传统絮凝沉降速率的3.64倍;絮体粒径D₅₀也达到最大值41.94μm,较传统絮体粒径大20μm。磁粉投加量过多或过少、粒径过大或过小都会相应地减慢磁絮体的生长速率。     

聚合氯化铁混凝—超滤—氯消毒处理原水的研究

采用聚合氯化铁(PFC)作为混凝剂对腐殖酸-高岭土模拟水样进行混凝—超滤—氯消毒处理,分析混凝絮体特性和超滤处理过程对消毒副产物前驱物的生成趋势的影响。结果表明,PFC混凝效果随着投加量的增大而增强;投加量为12 mg/L时,酸性条件有利于增强混凝效果;超滤过程可以去除混凝出水中的大分子有机物,但对快速反应物的去除效果却不明显;在絮体粒径500μm的范围内,絮体粒径的增大有利于快速反应物的去除,从而降低了消毒副产物的生成潜能。     

磷矿酸解料浆与高分子絮凝剂形成的絮团特性研究

用光学连续摄像技术研究了不同絮凝条件下磷矿酸解渣与聚丙烯酰胺形成的絮团特性。实验结果表明酸解料浆与聚丙烯酰胺絮凝剂形成的絮团具有分形几何特征。应用分形理论得到絮团降落速度与絮团孔隙度和絮团密度的关系式。用激光粒度分布仪在线测定了流体力学条件对该体系团强度的影响。在湍流情况下絮团最大平均粒径取决于酸解渣原始平均粒径和体系的能量耗散。较大的絮团破坏主要以裂解为主,在最小的湍流漩涡区也存在相当程度的剥离破坏。试验发现絮团强度随聚合物分子量的增加而提高,对于获得最大平均粒径的稳定絮团存在最佳的絮凝剂加入量。．     

高分子絮凝剂对泥沙絮体分形结构的影响

黄河泥沙架桥絮凝沉降实验与电镜实验研究表明,絮体结构具有分形特性。文章讨论了高分子絮凝剂的架桥絮凝机理以及高分子所带电荷种类、高分子的分子量、投加剂量与浓度对絮体分形结构的影响,并用表征絮体结构分形特性的参数“分维D”定量分析了这种影响规律。同时,对比了相同含沙量下无机混凝剂絮体与高分子架桥絮体结构达最佳时的分形特征及所需的混凝控制指标Gt值。