混凝、粉末活性炭吸附对不同分子量有机物的去除

实验对黄河原水及经混凝吸附、粉末活性炭吸附处理后水中有机物的分子量分布进行了测定。实验结果表明：混凝过程主要去除分子量大于6000的有机物，去除率达到40％；粉末活性炭吸附主要去除分子量在500～1000和1000-3000，去除率分别达到21．52％和24．15％；混凝和活性炭吸附对分子量小于500的有机物都没有去除效果。     

H_2O_2预氧化-粉末活性炭吸附深度处理制药废水二级生化出水的研究

针对以小分子为主、难生物降解制药废水的二级生化出水,研究了混凝、粉末活性炭（PAC）吸附、H2O2氧化和H2O2预氧化-PAC吸附联合的方法对CODCr的去除效果的差异。试验结果表明：H2O2预氧化-PAC吸附协同处理,对CODCr有着很好的去除效果。当制药废水二级生化出水CODCr的质量浓度为1 067 mg/L时,投加1.0 g/L的H2O2预氧化15 min后,再投加1.0 g/L的PAC吸附,对CODCr的去除率达到50%～60%,CODCr去除效果得到提高。     

H2O2预氧化-粉末活性炭吸附深度处理制药废水二级生化出水的研究

针对以小分子为主、难生物降解制药废水的二级生化出水,研究了混凝、粉末活性炭(PAC)吸附、H2O2氧化和H2O2预氧化-PAC吸附联合的方法对CODCr的去除效果的差异.试验结果表明:H2O2预氧化-PAC吸附协同处理,对CODCr有着很好的去除效果.当制药废水二级生化出水CODCr的质量浓度为1067mg/L时,投加...     

受微污染湘江原水强化水处理工艺研究

采用强化混凝工艺、强化混凝与活性炭联用工艺对湘江微污染原水及低温低浊原水进行中试研究。结果表明，对于处理受微污染湘江原水，聚合氯化铝混凝效果最佳；处理湘江低温低浊原水时，聚合硫酸铁效果最佳：高产酸钾与粉末活性炭联用助凝，能有效地去除有机物；强化混凝与活性炭联用处理工艺能有效地去除湘江原水；有机物以及消毒副产物前体，还能增加活性炭吸附能力。     

粉末活性炭对焦化反渗透浓水的吸附选择性研究

以活性炭为主的吸附材料在面对工业尾水时对不同种类有机污染物的吸附存在一定的差异并难以彻底去除。实验通过粉末活性炭（PAC）对焦化反渗透浓水（ROC）的吸附过程进行解析，结果表明，PAC的吸附选择性主要基于两个方面的因素：一方面，十四烷、角鲨烯等部分长链有机物的分子直径大于PAC的最佳吸附孔径（0.5～1 nm），因此难以得到有效去除；另一方面，有机物对PAC表面大量含氧官能团的相互竞争以及PAC表面含氮官能团的缺少，使得苯酚类有机物与PAC之间的相互作用降低。从PAC对ROC的吸附过程来看，吸附启动阶段PAC主要依靠孔道通过物理作用吸附芳香类有机物，而在吸附中期则依靠表面官能团与有机物的相互作用吸附烷烃、烯烃等非芳香族有机物，整体吸附过程更符合拟二级动力学和Freundlich等温模型。     

O3-BAC污水深度处理工艺对有机锡和壬基酚的去除

评价了臭氧生物活性炭（O3-BAC）联用技术深度处理经过混凝沉淀和砂滤处理的城市污水二级处理水过程中内分泌干扰物有机锡和壬基酚的去除效果。在臭氧消耗量和反应时间为5mg／L和10min，BAC空床停留时间为10min的条件下，臭氧氧化对有机锡化合物MBT、DBT和TBT的平均去除率分别为99．9％、71．2％和15．5％，有机锡中的丁基数量对臭氧氧化效果表现出明显的影响。生物活性炭对MBT、DBT、TBT和MPT的平均去除率分别为87．8％、87．9％、23．3％和21.3％。臭氧可以完全氧化另外一种内分泌干扰物壬基酚（NP）。     

用有机物分子量分布变化评价不同处理方法去除有机物的效果

本文就不同的净水处理引起的水中有机物分子量分布的变化进行了探讨。混凝处理去除大分子有机物，粉末活性发不仅能有效地去除小分子有机物，对大分子量的有机物也有很好的去除效果。臭氧主要氧化大分子有机物，生物预处理由于微生物新陈代谢产物的影响，没有分子量变化的规律性。根据水源有机物分子量分布和净水处理去除不同分子量有机物的特点，可达到净水处理工艺的最佳组合。     

粉末活性炭粒径对PAC-UF工艺处理效能的影响

采用3种粒径的粉末活性炭(PAC,50μm、3μm、200 nm),考察了PAC粒径变化对天然有机物的吸附性能和吸附前后的水中有机物分子量分布的影响,探讨了不同PAC投加量、投加方式和吸附程度条件下,PAC粒径对PAC-UF工艺处理效果以及膜污染的影响。结果表明,PAC可以有效地吸附UF膜难于截留的小分子量有机物,粒径减小有助于增强其对30 k~100 k分子质量有机物组分的吸附;PAC投加量增加和粒径减小均增大了其吸附容量,提高了PAC-UF工艺的有机物去除率,并进一步减缓了膜污染;集中式投加并未因为与有机物的接触时间延长而改善PAC-UF工艺的去除率和减缓膜污染程度,连续式投加是PAC-UF工艺最有效的投加方式;此外,PAC与有机物在膜面形成的活性炭滤饼层,可以对有机物起到额外截留的作用,而缓解膜污染的主要原因是PAC对有机物的吸附去除,吸附饱和的PAC会加剧膜污染。     

改性沸石耦合活性炭强化混凝处理微污染源水

采用静态吸附和六联搅拌烧杯实验进行组合改性沸石粉(MZ)耦合粉末活性炭(PAC)强化混凝去除微污染源水氨氮(NH3-N)、耗氧量(CODMn)、UV254和浊度等效能研究。结果表明，组合改性后沸石粉的比表面积和平均吸附孔径增加，对NH3-N交换去除能力增强。MZ和PAC联用吸附对去除NH3-N具有协同作用，对去除CODMn略有拮抗作用。而MZ耦合PAC强化混凝则显著提高了NH3-N, CODMn, UV254和浊度的去除效果，出水NH3-N<0.5 mg/L, CODMn<3.0 mg/L, 浊度<1 NTU。MZ和PAC不同投加方式显著影响强化混凝处理效果，其中最佳投加方式为絮凝初期投加PAC和MZ，避免絮体包裹MZ，加强PAC对有机物的去除，进一步提高MZ对NH3-N的去除效果。耦合强化混凝使Zeta电位的绝对值降低，胶体间斥力减少，絮体粒径增大，粘黏现象明显，抗冲击能力更强。     

改性膨润土-混凝联用处理水体中持久性有机污染物PFOS

对比了改性膨润土-混凝联用和粉末活性炭-混凝联用处理水体中的持久性有机污染物全氟辛磺酸(PFOS)的效果,并对溶液pH值的影响进行了考察。结果表明,在PAC的最佳投药量10 mg/L时,改性膨润土吸附-混凝联用对PFOS和浊度的去除率分别达到了96.05%和95.32%,处理效果优于粉末活性炭-混凝联用。pH值对改性膨润土吸附-混凝联用处理PFOS影响显著,随着pH的升高PFOS的去除率呈先上升后下降趋势,余浊随pH值得升高而减小。以改性膨润土替代粉末活性炭联用混凝既能有效去除水体中的PFOS,也可以降低处理成本。     

Performance of Flocculation and Adsorption Pretreatments to Ultrafiltration of Biologically Treated Sewage Effluent: the Effect of Seasonal Variations

Abstract

The effect of seasonal variations on ultrafiltration (UF) following pretreatment was investigated in terms of organic removal, removal of fraction, and molecular weight (MW) distribution. The MW range of effluent organic matter (EfOM) in biologically treated sewage effluent during winter (BTSE‐W) consisted of large MW. However, the MW ranged from 3000 to 200 daltons in biologically treated sewage effluent in the summer (BTSE‐S). During filtration experiments of BTSE‐S, the UF NTR 7410 filter showed rapid flux decline with time without pretreatment. FeCl₃ flocculation removed the hydrophobic (HP) and hydrophilic (HL) fractions with different trends. In winter the HP fraction was removed up to 68.5%, whereas during the summer season, the HL fraction was removed by up to 59.8%. Flocculation removed large MW organics together with small MW, while PAC removed the majority of small MW organics. The flux decline with adsorption was also more severe than that with flocculation. Considering MW distribution, when large MW was removed by flocculation, the flux decline was minimized, whereas PAC adsorption which removed small MW still decreased the permeate flux.     

Application of hybrid photocatalysis systems coupled with flocculation and adsorption to biologically treated sewage effluent for organic removal

The application of a photocatalysis hybrid system coupled with flocculation and adsorption in treating biologically treated sewage effluent (BTSE) was investigated. The removal of organic matter was studied in terms of dissolved organic matter (DOC), removal of hydrophobic (HP), transphilic (TP) and hydrophilic (HL) fractions, and molecular weight (MW) distribution. The photooxidation removed the majority of MW (263, 580, 865, and 43109 daltons) within the first 30 minutes of operation. The removal of MW range of organic matter of 330 daltons was low. DOC removal of HP and TP was high (80%). DOC removal from HL fraction was, however, minimum. The photocatalytic system with simultaneous PAC adsorption and FeCl₃ flocculation removed the effluent organic matter (EfOM) up to 90%. Therefore, photocatalysis with the ferric chloride (FeCl₃) flocculation and PAC adsorption hybrid system can be a possible option in the removal of DOC from BTSE for water reuse.     

浸没式PAC-AMBRs系统中PAC缓解膜污染的研究进展

浸没式粉末活性炭-好氧膜生物反应器(powdered activated carbon-aerobic membrane bioreactors,PAC-AMBRs)是一种利用PAC吸附性、微生物降解性和膜分离特性的新型废水处理技术。本文重点分析了近20年来浸没式PAC-AMBRs系统直接投加PAC缓解膜污染机制的研究成果，探讨了PAC通过对污泥絮体和溶解性有机物的综合影响缓解膜污染的机制，分析了PAC投加量和补充率对膜污染的影响。通过分析可知PAC缓解膜污染是一个综合作用的结果。以PAC为载体形成的污泥絮体在膜表面形成结构疏松和抗压性强的滤饼层，不仅能有效降低滤饼层阻力(cake resistance,R_c)，还可以作为自成型动态膜截留溶解性有机物和悬浮微生物等来减少此类污染物造成的膜污染。PAC通过吸附和/或表面附着的微生物降解溶解性有机物的协同作用降低其造成的过滤阻力。定期排出和补充一定量的PAC可以提高缓解膜污染的效率。     

超滤组合工艺深度处理城市污水研究

考察了4种超滤组合工艺(精滤-超滤、精滤-活性炭-超滤、精滤-活性炭-精滤-超滤和混凝沉淀-超滤)对城市污水的深度处理效果.结果表明,4种超滤组合工艺对浊度的去除率都很高,最高达92.2%,均能保证出水浊度低于1 NTU,说明超滤膜对浊度的去除效果很好;4种超滤组合工艺对有机物的去除率比较高,其中精滤-活性炭-精滤-超滤对有机物的去除效果最好;超滤膜对TN和NH_3-N的去除率比较低;4种超滤组合工艺的初始膜通量不同,精滤-活性炭-精滤工艺出水通量下降较快.     

投加粉末活性炭对超滤膜去除海水中有机物的影响

超滤膜的有机污染问题是膜法海水预处理技术在海水淡化工程应用面临的重要挑战,粉末活性炭吸附是目前常用的膜前预处理手段之一。本文对比分析了直接超滤和投加粉末活性炭后对海水中有机物的截留能力,利用三维荧光光谱分析了投加粉末活性炭对超滤膜截留有机物的影响机制,并考察了海水超滤过程中通量变化及膜污染情况。研究结果表明,投加粉末活性炭能够强化超滤膜对海水浊度和有机物的去除,当粉末活性炭投量为200mg/L时,整个系统对海水中DOC去除率从直接超滤时的55.1%提高到77.6%。利用粉末活性炭的吸附作用及其在超滤膜表面形成的疏松滤饼层能够显著提高超滤系统对海水中腐植酸类有机物的去除能力。与直接超滤相比,粉末活性炭-超滤系统对改善膜通量的作用有限,但粉末活性炭形成的滤饼层能够避免超滤膜与有机物直接接触,可显著减缓超滤膜的不可逆污染。     

原水深度处理过程中的生物稳定性和分子量分布

研究了水源水在"预臭氧+常规+主臭氧/生物活性炭"深度处理工艺流程净化中的各工艺段出水有机物及分子量的变化特征,建立了生物稳定性与有机物分子量的关系,实现了对深度处理后供水水质生物稳定性的评估。研究结果表明:预臭氧可将大分子的天然有机物分解为相对分子质量小于1000的有机物,并提高水的可生化性;导致常规处理工艺去除水中有机物的效率降低;主臭氧可将有机物进一步氧化,并将部分氧化成相对分子质量小于500的有机物;生物活性炭可提高出水的生物稳定性,但对相对分子质量小于1000的有机物去除有限;分子量越小生物稳定性越差,越不容易被去除。此研究结果为评估水源水质深度处理的生物稳定性提供了理论依据。     

Role of membrane pore size in tertiary flocculation/adsorption/ultrafiltration treatment of municipal wastewater

Flocculation, adsorption onto powered activated carbon (PAC), and ultrafiltration (UF), alone and in combination, were tested for tertiary treatment of the secondary effluent from municipal wastewater treatment at the Ashkelon plant (in southern Israel). Encouraging and reliable results of total organic carbon (TOC) of <3 mg/l were achieved with a combination of 130 mg/l FeCl₃, 0.6 g/l PAC and UF. The relative contribution of the UF membrane to the reduction of TOC changed with the molecular weight cut-off (MWCO) of the membrane, from a negligible 2.9% for a 100-kDa-MWCO membrane to 17% for 10- and 2-kDa membranes. The latter membranes, however, developed significant fouling, with a 35% drop in flux during first 30 min of the filtration cycle. The flux drop for the 50- and 100-kDa membranes was in the low range of 3%. The optimal MWCO interval of 20- to 50-kDa in combination with flocculation/PAC pretreatment gave a significant reduction in organic content with minimal membrane fouling. Detailed GC–MS analysis showed that the combined treatment gave very efficient retention of organic compounds with molecular weights below 800 Da, with the consequent absence of harmful compounds in the tertiary effluent. It was therefore concluded that the recommended flocculation/adsorption protocol constitutes an effective pretreatment for UF and that the obtained tertiary effluent can be used for unrestricted irrigation.     

Application of ultrafiltration hybrid membrane processes for reuse of secondary effluent

This study evaluates the factors affecting pretreatment conditions for hybrid UF membrane processes for reuse of secondary effluent from the sewage treatment plant. The experimental results obtained from the ultrafiltration (UF) membrane process showed that the particles of the size range between 0.2 and 1.2 μm caused a significant impact on membrane fouling in all cases even with or without the coagulation process. As pretreatment of UF membrane process, the coagulation significantly improved the permeate flux. Optimal flux improvement was seen at an alum dose of 50 mg/L. In addition, it was found that the permeate flux was least declined under the coagulation condition of charge neutralization (pH 5.0). Also, the powdered activated carbon (PAC) adsorption enhanced the permeate flux. Application of the direct filtration as a pretreatment of UF membrane process was also very effective in reducing the UF membrane fouling.     

城市污水二级出水有机物性状及对膜污染的贡献

将城市污水二级出水中溶解性有机物分为强疏水性、弱疏水性和亲水性组分,研究其对超滤膜的污染。测定结果表明,二级出水中有机物对膜污染影响程度顺序为:强疏水性有机物>亲水性有机物>弱疏水性有机物。究其原因:(1)膜污染与有机物分子量大小有关,膜选择性地截留强疏水性有机物主要是这类有机物分子量较大所致。(2)从三维荧光光谱图上看,3个组分中均含有腐殖酸类荧光峰,说明腐殖酸类物质对膜通量的衰减贡献最大。(3)强疏水性组分中所含有机物最为复杂,荧光峰最为明显,由此可见膜污染的程度不仅与组分中所含有机物的种类有关,而且与其含量有关。此外,膜被有机物污染的程度与膜对有机物的去除率有着密切的关系。总荧光强度(FLU)可作为总有机物含量的一种指标来反映有机物被膜截留的情况。     

天然有机物对混凝除藻的影响

试验研究了天然有机物(腐植酸、富里酸)对混凝除藻的影响,以及在含有天然有机物水体中混凝除藻的机理.结果表明,天然有机物会与藻细胞争夺絮凝剂,由于天然有机物与PAC亲和力强,PAC优先与天然有机物结合,再与藻细胞结合,当水体中天然有机物含量较多时,混凝除藻效果降低.当腐植酸质量浓度为20.2 mg/L时,藻去除率仅为2....