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.     

臭氧-生物活性炭-砂滤组合工艺运行效果分析

介绍某水厂采用"臭氧-生物活性炭-砂滤"深度处理组合工艺处理引黄水库水,考察了不同进水浑浊度对组合工艺长期运行效果的影响,同时对组合工艺各单元的有机物种类及分子量分布的变化进行了分析。长期运行结果表明:(1)组合工艺对不同水质条件下的有机物指标有较高的去除效果,较高的温度有利于水中有机污染物的去除。(2)臭氧的主要作用在于将大分子量的有机物氧化为小分子量有机物,故臭氧生物活性炭工艺对COD_(Mn)2、UV_(254)和DOC有良好的去除作用。整个工艺对氨氮的去除率在40%~50%,对亚硝酸盐氮的去除率在80%~90%。(3)臭氧活性炭工艺对可生物降解有机物有较好的去除效果,砂滤工艺主要去除D0CDA。(4)上向流BAC柱活性炭颗粒间空隙率较大,降低了对浊度的机械截留,其后置的砂滤池可起到稳定出水浊度,保证出水微生物安全性的作用。     

浸没式超滤膜组合工艺处理饮用水的中试研究

通过中试实验研究了混凝沉淀-超滤、混凝沉淀-砂滤-超滤和混凝沉淀-升流式曝气生物活性炭-超滤三种工艺处理饮用水的净水效果及对膜污染影响情况。结果表明,3种工艺的浊度和颗粒数去除率均能达到99%以上且不受原水水质影响,都能去除水中大多数的微生物和浮游动物,说明超滤膜组合工艺能有效的保证出水的生物安全性。超滤膜本身对水中溶解性有机物和氨氮的去除效果较差,相对于混凝沉淀-超滤工艺,选用混凝沉淀-砂滤-超滤工艺和混凝沉淀-升流式曝气生物活性炭-超滤工艺对COD_(Mn)、UV_(254)及氨氮的去除率分别提高了21.2%、18.2%、28.6%和40.8%、63.7%、59.2%,且这两种工艺的过滤阻力也远小于混凝沉淀-超滤工艺的过滤阻力。     

不同超滤组合工艺净水及膜污染的中试研究

采用超滤中试系统处理深圳某水库原水,对比研究了粉末活性炭和混凝2种预处理工艺对超滤净水效果及对超滤膜污染的影响。结果表明,混凝/超滤工艺和粉末活性炭/超滤工艺对浊度、CODMn、UV254、DOC的平均去除率分别为99.6%、34.8%、31.3%、24.9%和99.4%、35.0%、32.4%、29.5%。粉末活性炭/超滤工艺对以CODMn、UV254、DOC表征的有机物的去除效果优于混凝/超滤工艺,而混凝/超滤工艺对有机物的去除效果受原水水质的影响较小,并且出水浊度效果稍好。在原水水质和运行条件相同的情况下,混凝/超滤工艺的跨膜压差的增长速度明显高于粉末活性炭/超滤工艺;但对超滤膜进行化学清洗后,粉末活性炭/超滤工艺膜表面仍有明显的污染物残留。     

超滤膜组合工艺处理砂滤池反冲洗水试验研究

针对净水厂砂滤池反冲洗水(FBWW)的水质特点,通过混凝-粉末活性炭-超滤工艺对砂滤池反冲洗水进行处理,以期达到反冲洗水安全回及节水节能之目的。研究结果表明,聚合硫酸铁(PFS)和粉末活性炭(PAC)投加量分别为8和15 mg/L时,混凝-粉末活性炭-超滤膜组合工艺对FBWW中浊度、DOC和UV254的平均去除率分别为99.8%、40.54%和51.39%;该组合工艺对疏水性有机物去除率大于对亲水性有机物去除率;与FBWW原水相比,组合工艺出水中三卤甲烷生成潜能降低了78.75%。因此,混凝-粉末活性炭-超滤膜组合工艺用于FBWW的处理并安全回用是切实可行的,具有理论及实际意义。     

粉末活性炭-超滤膜处理微污染水试验研究

基于超滤膜对有机物去除率低和超滤膜污染严重的现状,构建了传统工艺+超滤以及传统工艺+粉末活性炭(PAC)+超滤两组工艺,并对处理前后水样的浊度、UV_(254)、高锰酸盐指数进行检测,对比了两组工艺对微污染水中的污染物的处理效能。结果表明,两组工艺对于浊度的去除效果都比较好,出水浊度不受原水水质的影响,传统工艺+超滤组合工艺对于有机物的去除效果不理想;传统工艺+PAC+超滤组合工艺对有机物有着良好的去除效果,出水的浊度、UV_(254)和高锰酸盐指数的去除率分别为90.9%,84.6%和77.0%;超滤膜表面污染物主要为腐殖酸类物质和蛋白质类物质,经过化学清洗,基本上能恢复TMP,PAC的存在能有效减缓超滤膜的污染。     

粉末活性炭-超滤膜处理微污染水试验研究

基于超滤膜对有机物去除率低和超滤膜污染严重的现状,构建了传统工艺+超滤以及传统工艺+粉末活性炭(PAC)+超滤两组工艺,并对处理前后水样的浊度、UV_(254)、高锰酸盐指数进行检测,对比了两组工艺对微污染水中的污染物的处理效能。结果表明,两组工艺对于浊度的去除效果都比较好,出水浊度不受原水水质的影响,传统工艺+超滤组合工艺对于有机物的去除效果不理想;传统工艺+PAC+超滤组合工艺对有机物有着良好的去除效果,出水的浊度、UV_(254)和高锰酸盐指数的去除率分别为90.9%,84.6%和77.0%;超滤膜表面污染物主要为腐殖酸类物质和蛋白质类物质,经过化学清洗,基本上能恢复TMP,PAC的存在能有效减缓超滤膜的污染。     

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。     

接触氧化-强化混凝组合工艺处理低碳源城镇污水

在低碳源条件下,研究了接触氧化-强化混凝组合工艺处理城镇污水的运行结果.结果表明,当进水COD96～180 mg·L-1、ρ(NH3-N)17～45 mg·L-1、ρ(TP)2～6.5 mg·L-1时,其去除率分别可达到70%、85%、90%,浊度去除率为95%,出水水质达到城镇污水处理厂污染物排放标准(GB18918-2002)一级排放A标准,出水可回用.GC-MS分析表明,接触氧化一强化混凝组合工艺具有很强的有机物去除能力.     

臭氧+混凝沉淀处理微污染水试验研究

研究臭氧 混凝沉淀处理低温微污染水的净水效果.采用静态试验,改变臭氧投加量,接触氧化时间等参数,分别对比了CODMn、浊度和色度的去除效果.臭氧投加量为3 mg·L-1接触氧化时间为15 min时,沉淀后出水的高锰酸盐指数、浊度、色度比直接采用聚合氯化铝混凝的去除率分别提高了5.4%、20.3%和20.1%.对于低温微污染水源水,臭氧 混凝沉淀工艺能有效地去除有机物、浊度、色度,使处理后水质达到饮用水水质标准.     

Loss of ammonia after application of urea at different times to dry-seeded,irrigated rice

Ammonia loss from urea applied to dry-seeded rice, determined using a micrometeorological technique, varied considerably depending on the time of application. Ammonia volatilization was negligible, before and after flooding, when urea was applied to the dry soil surface two days before permanent flood. Before flooding, the urea prills remained undissolved and urea hydrolysis could not proceed. Thus there was no source of fertilizerderived ammonia for volatilization to occur. Upon flooding, the urea prills were washed into cracks in the soil which subsequently closed. Therefore the movement of soluble nitrogen into the floodwater was prevented, and again there was no ammonia source for the volatilization process.When urea was broadcast into the floodwater a few days after permanent flood, ammonia losses were high and varied from 11–21% of the nitrogen applied. These losses were associated with high floodwater pHs and high wind speeds near the water surface.However, when urea was applied into the floodwater at panicle initiation, ammonia losses were low (3–8% of the applied nitrogen). At this stage of growth the plant canopy shaded the floodwater, inhibiting algal photosynthesis and consequent pH elevation, thus resulting in low ammonia gas concentrations at the floodwater surface. In addition, the plant canopy restricted air movement at the water surface, thereby reducing ammonia transport away from the air-water interface.These findings provide basic information required for improving current fertilizer management practices.     

臭氧-活性炭工艺在给水处理中的作用研究

根据国内外大量的案例数据,全面总结分析了臭氧-活性炭工艺在给水处理中对有机物的去除效果,并对去除机理进行了科学分析和探讨。同时对这一工艺的应用情况进行了介绍。研究认为,臭氧-活性炭工艺对有机物的去除效果十分有效,对CODMn去除效果比较稳定,去除率一般在40%～50%,而且耐有机污染冲击负荷较大。     

Incorporation of urea for transplanted rice as affected by floodwater and growing season

Incorporation of urea into puddled rice soils is known to reduce ammoniacal-N buildup in floodwater and the subsequent loss of N as ammonia. Little is known, however, about seasonal and temperature effects on the effectiveness of basal urea incorporation in puddled soils. A field experiment was conducted in northern Vietnam on an Aquic Ustifluvent in the spring season (February to June) and summer season (July to November) to determine the effect of the presence of floodwater and method of fertilizer incorporation on floodwater ammoniacal-N, floodwater urea-N, andpNH₃ following urea application. During the 4 d following basal urea application, floodwater temperature at 1400 h was 7 to 15°C higher in summer (July) than that in spring (February), and floodwater pH at 1400 h was 0.5 to 1.0 higher in summer than that in spring. ThepNH₃ was much higher in summer than that in spring, suggesting a high potential for ammonia volatilization in summer. The movement of transplanters through the field did not reducepNH₃, irrespective of floodwater depth (0 or 5 cm) and season. Harrowing and subsequent transplanter movement partially reducedpNH₃ in the summer;pNH₃ reduction, however, was greater when floodwater depth was 0 rather than 5 cm during harrowing and transplanting. This partial reduction ofpNH₃ in summer did not result in a corresponding increase in rice yield, presumably because N losses were only slightly reduced and because yield was constrained by additional factors, such as the adverse climate. In spring, the removal of floodwater before urea application and incorporation increased grain yield by 0.2 Mg ha^–1, even thoughpNH₃ was consistently low and was not reduced by urea incorporation. This result suggests that water management and tillage during basal urea application may influence rice growth and yield in ways other than reduced N loss.     

Removal of Poly Aromatic Hydrocarbons (PAHs) from Water: Effect of Nano and Modified Nano-clays as a Flocculation Aid and Adsorbent in Coagulation-flocculation Process

Water treatment process involving simultaneous action of adsorption on different nano and organo-modified nano-clays followed by coagulation-flocculation by alum and poly aluminium chloride (PAC) has been evaluated for the removal of PAHs (naphthalene, acenaphthalene, phenanthrene, fluoranthene, anthracene, and pyrene) from water. When clay minerals along with alum and PAC were used for treatment, 37.4–100.0% removal of PAHs was observed compared to 20–38% removal using normal water treatment process with either alum or alum + PAC. The effectiveness of clay minerals for removal of PAHs followed the order (P < 0.05): halloysitenano-clay (HN-clay) < normal bentonite (NB-clay) < hydrophilic nano-bentonite (HNB-clay) < nano-montmorillonite modified with dimethyl dialkyl amine (DMDA-M-clay) ≈ nano-montmorillonite modified with octadecylamine and aminopropyltriethoxysilane (ODAAPS-M-clay) ≈ nano-montmorillonite modified with octadecylamine (ODA-M-clay) in combination with alum + PAC. The modified treatment process (alum + PAC + clay minerals), where water was initially treated with clays followed by normal process of coagulation (alum + PAC), was found to be the most effective method with maximum removal for ODAAPS-M-clay (97.7–100.0%) which is at par wih ODA-M (97.0–100.0%), and DMDA-M-clay (94.8–100%). The removal of PAHs varied in the order: naphthalene ≈ acenaphthalene > anthracene ≈ pyrene > phenanthrene > fluoranthrene. The treatment combination having the maximum removal capacity was also used eficiently for the removal of PAHs from natural and fortified natural water. This article demonstrated adsorption-coagulation integrated system has the potential to remediate PAHs polluted water.     

Oxidized carbon nanotubes for simultaneous removal of endrin and Cd(Π) from water and their separation from water

BACKGROUND: Previous investigation has shown that carbon nanotubes (CNTs) are effective for the removal of organic pollutants and oxidized carbon nanotubes (OCNTs) are effective for the removal of heavy metals. In this investigation, OCNTs were used for simultaneous removal of endrin and Cd(Π) from water. Separation of OCNTs from water was also investigated. RESULTS: The removal efficiencies of endrin and Cd(Π) by OCNTs were 89–97% and 96–100%, respectively. Endrin removal capacity of OCNTs is approximately the same as that of powdered activated carbon (PAC) and as‐prepared CNTs. Cd(Π) removal capacity of OCNTs is much higher than that of PAC and as‐prepared CNTs. OCNTs can be separated efficiently from water using AlCl₃. CONCLUSION: OCNTs are effective for the simultaneous removal of endrin and Cd(Π) and after adsorption, OCNTs can be separated from water by dosing AlCl₃. Copyright © 2008 Society of Chemical Industry     

Incorporation of urea in puddled rice soils as affected by tillage implements

Thorough incorporation of urea into the soil is known to reduce the high N losses associated with the traditional practice of broadcasting urea onto puddled lowland rice fields. Few studies have, however, examined the effectiveness of farm-level implements for incorporating broadcast urea during final land preparation in small rice fields. A field experiment was conducted at two sites in the Philippines to compare the effectiveness of several commonly available and experimental tillage implements for basal incorporation of urea. The relative effectiveness of N incorporation and relative susceptibility of N to ammonia volatilization losses were assessed from floodwater (urea + ammoniacal)-N and partial pressure of ammonia (pNH₃) following urea application to puddled, unplanted soil.Conventional water buffalo- and single axle tractor-drawn comb harrows were equally, but only partially, effective in reducing floodwater (urea + ammoniacal)-N andpNH₃ by 42 to 56% of the values for broadcast prilled urea (PU) without incorporation. Removal of the comb harrow from the single axle tractor did not reduce the effectiveness of PU incorporation, indicating that the cagewheel rather than the comb harrow was largely responsible for fertilizer incorporation. An experimental conical puddler was slightly more effective than the conventional comb harrow. The movement of transplanters through the field did not effectively incorporate PU. A power weeder, frequently used by researchers to incorporate fertilizer in small experimental plots, was less effective than traditional comb harrows, reducing floodwater (urea + ammoniacal)-N by only 35%. No tillage implement for incorporating urea reducedpNH₃ as effectively as did the liquid urea band injector.Results suggest that sizeable losses of fertilizer N still occur following incorporation of PU with tillage implements commonly used by small rice farmers. Considerable scope remains for the improvement of fertilizer incorporation in puddled rice soils.     

富营养化水体中致臭物质来源及其处理

以某水库水为原水,研究了5种给水处理工艺对水体藻类导致的嗅味的去除效果。试验结果表明:除常规处理工艺(嗅阈值去除率50%左右)外,其余4种工艺都可达到90%以上的除臭率。臭氧-粉末活性炭-常规处理工艺对嗅阈值的去除率最高,达到98%。实际应用中,建议臭氧的投加量为2mg/L、粉末活性炭的投加量为5mg/L。     

常规处理与深度处理工艺对南京长江原水中有机物去除效能比较

以长江南京段原水为研究对象,通过常规处理及深度处理工艺(强化过滤工艺和生物活性炭工艺)对长江南京段水源水中有机物的去除效能进行对比研究。结果表明常规工艺对CODMn、UV254、DOC及BDOC的去除率分别为30%、41%、27%及25%。强化常规工艺和生物活性炭工艺各指标的去除率分别为34%和52%、48%和50%、37%和40%及74%和82%。强化过滤工艺及生物活性炭工艺对1,2,4-三氯苯的去除效果明显,能显著提高出水水质。常规工艺对MW大于5 kDa的有机物去除效果明显,强化过滤工艺对MW小于1 kDa的有机物去除率大于25%,生物活性炭工艺对各个分子量区间的去除效果都比较好,特别是对原水中占多数的MW小于1 kDa的有机物去除率大于30%。     

Phenol Removal from Aqueous Solution through Hollow Fiber Membrane Extraction

In this work,mass transfer mechanism was studied for 50%TBP( in kerosene) -phenol-water as the working system in different bydrophobic microporous hollow fiber modules. The effect of different operating conditions on the removal of phenol was aanlyzed. Solvent entraimment in this process was detected with MALVERN-2600 laser pellet diameter analytical equipment. Experimental reaults indicate the mass transfer coefficient is incressed while the two phase flow raten are inerassed. With incesses in the flow rate of the water phase,the removal ratio of phenol will be decreased. Highly effective removal of phenol could be reached by changing the experimental conditioms and the module configurstion. The solvent entraimment in the water phase in the mernbrane extraction process was found to be 5%-8% of that in conventional liquid-liquid extraction process. Thus,solvent pollution could be better controlled.     

富氧生物处理微污染水源水除微量有机化学污染物研究

为提高微污染水源水的饮用水质安全性,采用弹性填料微孔曝气富氧生物接触氧化工艺处理受污染的某水源原水,进行了除微量有机化学污染物的比较研究。GC-MS分析表明,受污染原水经富氧生物处理后,有机化学污染物种类减少了65.1%,有机优先化学污染物种类减少60.0%。富氧生物处理工艺对原水中几种微量有机优先化学污染物的去除作用大小不同。