混凝沉淀与混凝气浮处理含铊微污染北江水的对比研究

随着人类活动特别是采矿业的增加,铊(Tl)引起的水污染已经成为给水行业面临的严峻问题。以含Tl微污染北江水为处理对象,在不改变常规运行参数(包括沉淀时间、pH等)前提下,对混凝沉淀和混凝气浮两种工艺的效能进行了对比研究,重点考察两种工艺除Tl、除浊、除总有机碳(TOC)和除藻特点。结果表明,混凝沉淀和混凝气浮工艺的除Tl效率均随投药量的增加而提高。复合混凝剂PAC-PDM、AS-PDM除Tl效果优于PAC和AS。常规投药量范围内,沉淀除Tl和除浊效果优于气浮,但除藻效果较气浮略低。除Tl与除TOC之间存在一定相关性,最佳投药范围一致。综合考虑相关因素,对于含Tl微污染北江水而言,混凝除污最佳工艺为混凝沉淀,最优混凝剂及投药量分别为PAC-PDM和7mg/L。     

污水深度处理工艺化学强化除磷单元药剂选择及优化

试验采用化学除磷工艺补充处理河南某污水处理厂的改良氧化沟脱氮工艺二级处理出水,以达到深度除磷目的,使出水满足《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A的要求。分析聚氯化铝、聚硫酸铁和三氯化铁三种混凝剂对二级出水中总磷的去除效果,并确定其最合适的投加量。试验结果显示当二级处理水总磷为2～3 mg/L,出水总磷达到0.5 mg/L要求时,投加量:氯化铁聚氯化铝聚硫酸铁,即氯化铁的投加量最少;年投加混凝剂的费用:聚氯化铝氯化铁聚硫酸铁。综合考虑,最合适的混凝剂为聚氯化铝,其最合适的投加量为59 mg/L。     

气浮工艺处理南方微污染原水的混凝剂选择——以深圳水库为例

以深圳水库水为原水,选用聚合氯化铝(PAC)、硫酸铝和氯化铁作为气浮工艺的混凝剂进行分析处理,选择出适合深圳水库水的最理想混凝剂.试验结果表明:PAC、硫酸铝、氯化铁三者的最佳投药量分别为1.25、1.25、4mg/L;在各自的最佳投药量下,PAC对浊度、色度、CODMn的去除率都要优于硫酸铝、氯化铁,且使用PAC生成的浮渣量最少.因此选用PAC作为此气浮工艺的混凝剂进行后续研究.     

PDMDAAC复合PAC用于冬季低温低浊黄河水研究

阐述用有机阳离子高分子聚二甲基二烯丙基氯化铵(PDMDAAC)与无机混凝剂复合物对冬季低温低浊黄河水的脱浊处理研究过程。通过混凝烧杯实验,考察了药剂投加量及PAC与PDMDAAC的复合配比对低温低浊黄河水脱浊效果的影响。结果表明,对温度为8℃左右,浊度在50NTU以下的黄河水,PDMDAAC对PAC强化混凝脱浊效果明显,PAC与PDM-DAAC的复合配比越低,复合混凝剂脱浊效果越好。要达到6NTU的水厂沉淀出水余浊标准,PAC需1.3 mg/L左右的投加量,而脱浊效果较好的低复合配比药剂PAC投加量在1.0 mg/L左右,减少残余铝含量20%左右。     

利用正交试验优化再生水厂混凝沉淀运行参数

混凝沉淀的运行参数可以直接影响混凝沉淀的效果,针对某再生水厂的工艺特点与实际情况,通过L25(5)6正交试验确定了最佳搅拌强度和聚氯化铝(PAC)投药量范围,并利用生产性试验验证,得到优化的混凝沉淀运行参数。将优化结果应用于实际生产运行,混凝沉淀效果得到明显改善。     

载粉末活性炭过滤处理微污染原水的试验研究

载粉末活性炭(PAC)过滤集PAC吸附与过滤于一体,能够应用于微污染原水处理。配水试验结果表明:粒径为1.25-2.5mm,厚度为1000mm的聚苯乙烯滤料层能够用于载PAC过滤。影响过滤效果的主要因素为PAC载量和混凝剂投加量,当混凝剂T3010和聚氯化铝的投加量分别为0.09mg/L和2.5mg/L,PAC载量为2-3g/L滤料时,载PAC过滤处理浊度为20-40NTU的微污染原水的效果达到最佳,对CODMn和浊度都具有很好的去除效果。Z河水作为原水的试验结果表明:载PAC过滤对河水浊度、UV254、CODMn的去除率分别为97%-97.9%、50.9%-63.4%、68.5%-71.4%。     

给水厂混凝剂技术经济性验证流程重构及应用

在前期研究模糊综合评价方法的基础上建立了一套普适性的给水厂混凝剂评估验证流程方法,通过烧杯试验、中试优化评估混凝剂适用性及优选投加量,并结合技术经济性因素在实际水厂开展了规模化的验证,以期为水厂混凝剂的适用性筛选及其优化使用提供借鉴。烧杯试验采用标准流程对水厂常用的PAFC及PAC进行评价对比,中试阶段对烧杯试验所选投加量进行验证,生产验证主要是在经济投加量下,检测出水各项指标。结果显示:PAFC对目标水体的适用效果较好且优于PAC。烧杯及中试验证发现药剂的最佳投加量为4mg/L,但在生产验证阶段兼顾了技术经济性因素,确定最适投加量应为2mg/L。在此情况下,其出水浊度、TOC、COD_(Mn)以及UV_(254)的去除率分别达到了89.87%、7.5%、33.01%以及44.57%,絮体平均粒径达到了625μm,投药成本为0.07元/m~3。通过全流程评估验证综合评价:目标给水厂当前所用混凝剂以及投加量是相对科学合理的。     

不同混凝剂对深度脱水污泥水的预处理效果研究

在白龙港污水处理厂深度脱水污泥水水质特性分析的基础上,考察了聚氯化铝(PAC)、聚氯化铁(PFC)、阳离子型聚丙烯酰胺(cPAM)和阴离子型聚丙烯酰胺(aPAM)单独及复合投加对深度脱水污泥水预处理效果的影响。混凝剂主要去除深度脱水污泥水COD和总磷中的颗粒性部分,且各混凝剂的去除率无明显差异。与无机混凝剂PAC和PFC相比,有机混凝剂PAM更适合于深度脱水污泥水的混凝沉淀预处理。     

吹填泥浆的混凝沉降特性试验

为解决水力吹填泥浆自由沉降所需时间较长,退水排放会带走大量淤泥,以及吹填土地基自然固结时间长等问题,向泥水混合液分别投加聚合氯化铝(PAC)和聚丙烯酰胺(PAM),搅拌静置沉淀后测定混合液剩余浊度、剩余固体悬浮物质量浓度(SS)及泥水界面高度,考察其混凝沉降性能。试验结果表明,投加混凝剂能在一定程度上加速吹填泥浆的沉降分离,提高出水水质。随着PAC和PAM投加量的增加,混合液剩余浊度和剩余SS值均呈现先降低后升高的趋势,而泥水界面高度基本保持不变。当PAC投加量为360mg／L时,混合液剩余浊度和剩余SS达到最小值,分别为287.4和1.45g／L;当PAM投加量为2.8mg／L时,混合液剩余浊度和剩余SS最小,分别为752.7和2.83g／L。     

给水厂污泥减量化及性能改善研究

随着给水厂排泥水直排河道的方法不再可行,水处理过程中产生的污泥量和污泥性能将直接影响整个水厂的造价及运行费用。试验在水处理工艺流程相同的条件下,分别投加硫酸铝、氯化铁、聚铝(PAC)、聚铁(PFS)、聚铝铁(PAFC)、高效聚双酸铝铁(PAFCS)等不同混凝剂,以达到减少絮凝沉淀后排泥水的污泥量及改善排泥水的沉降和脱水性能的效果,并探讨了其作用机理。     

强化混凝技术处理南淝河污染水的效果

选用聚合氯化铁(PFC)、聚合硫酸铁(PFS)、聚合氯化铝(PAC)和聚合氯化铝铁(PAFC)作为混凝剂;选用阳离子型聚丙烯酰胺(CPAM)、阴离子型聚丙烯酰胺(APAM)和非离子型聚丙烯酰胺(NPAM)作为助凝剂,通过室内试验对比研究强化混凝技术中多种混凝剂单用及其和助凝剂联用对南淝河污染水的除浊和去污效果,并用于南淝河现场构建的混凝沉淀系统。结果表明,4种混凝剂单用时,PAFC对浊度、TP去除效果最优,对CODMn有良好的去除效果,且不影响原水的p H值,而PFC和PFS单用时可明显降低原水p H值,4种混凝剂单用时对TN均没有明显去除效果;PAFC与CPAM联用时对浊度的去除效果最佳,明显优于PAFC与APAM和NPAM联用和PAFC单用的效果;混凝剂与CPAM联用提高了其除浊和去除TP的能力,但不能明显改善其去除CODMn的效果,对原水p H和TN的影响与单用时相同。选取"PAFC+CPAM"作为南淝河示范工程的混凝剂和助凝剂,现场混凝沉淀出水水质稳定,浊度和TP的去除效果较好,去除率分别达到90%和80%,对CODMn的去除率约为52%,而对TN的去除效果有限,去除率约为22.4%。     

广东某市自来水厂投加PAM对出厂水效果影响研究

该文主要介绍了广东某市自来水厂加药系统同时投加聚合氯化铝(PAC)和聚丙烯酰胺(PAM)与单一投加聚合氯化铝(PAC)对水厂出水水质的影响效果,以出水浊度及耗氧量为评价指标,通过11、12月份的出水水质连续性检测,对比研究水厂增加了PAM投加后出厂水的影响效果,结果显示:在PAM投加量与原水的比例为0.15 ppm,PAC投加量与原水的比例为3 ppm的条件下,水厂出水效果较好,且运行成本较低。     

Application of chemical precipitation for piggery wastewater treatment.

Several series of experiments were conducted to investigate the treatment of piggery wastewater using chemical precipitation (CP) where various types of coagulants such as aluminium sulfate (Al2(SO4)3), poly aluminium chloride (PAC), ferric chloride (FeCl3), ferric sulfate (Fe2(SO4)3), ferrous sulfate (FeSO4) and ferrous chloride (FeCl2) were used. Throughout the experiments, CP was found to achieve high removal efficiencies for organic compounds and nutrients (nitrogen and phosphorus) from the piggery wastewater. Experimental results showed the optimal doses of FeCl3, Fe2(SO4)3, FeCl2 and FeSO4 was 2.0 g/L, while 0.31 g/L and 2.5 g/L were the optimum dose for PAC and Al2(SO4)3, respectively. The pH range 4-5 resulted in the best performance to all coagulants except FeCl2 and FeSO4, whose optimum pH were more than 6. Percentage removal efficiencies for COD were in the ranges of 70-80%, 90-95% for SS, 80-90% for organic-N and TP. Those removal efficiencies were achieved within 5 min of operation. Three times of repetition in CP resulted in higher removal efficiencies for COD, SS and colour up to 74%, 99% and 94% respectively, in which Al2(SO4)3 was used as the coagulant. Removal efficiencies of various water quality parameters in a continuously operated reactor were similar to those of the batch experiments. Biodegradable ratios (BOD5/COD) increased up to 65% after the application of CP.     

Impact of RO-desalted water on distribution water qualities.

A large-scale pilot distribution study was conducted to investigate the impacts of blending different source waters on distribution water qualities, with an emphasis on metal release (i.e. corrosion). The principal source waters investigated were conventionally treated ground water (G1), surface water processed by enhanced treatment (S1), and desalted seawater by reverse osmosis membranes (RO). Due to the nature of raw water quality and associated treatment processes, G1 water had high alkalinity, while S1 and RO sources were characterized as high sulfate and high chloride waters, respectively. The blending ratio of different treated waters determined the quality of finished waters. Iron release from aged cast iron pipes increased significantly when exposed to RO and S1 waters: that is, the greater iron release was experienced with alkalinity reduced below the background of G1 water. Copper release to drinking water, however, increased with increasing alkalinity and decreasing pH. Lead release, on the other hand, increased with increasing chloride and decreasing sulfate. The effect of pH and alkalinity on lead release was not clearly observed from pilot blending study. The flat and compact corrosion scales observed for lead surface exposed to S1 water may be attributable to lead concentration less than that of RO water blends.     

津河水体藻污染监测识别及无机混凝剂除藻效能研究

针对津河水体开展长达18个月的定点采样监测分析,对造成藻华现象的优势藻种进行了显微识别。结果表明,近两年津河水体总体为富营养化状态,其中每年7、8月份藻华暴发,呈现重富营养化特征,经观察鉴别属于微囊藻型蓝藻污染。以Chl-a、浊度及UV254为主要水质参数,探索投加无机混凝剂用于藻污染控制的可行性,并对4种混凝剂的藻污染控制效果进行了比较。结果表明,投加无机混凝剂控制津河藻污染效果显著(聚合氯化铝对Chl-a和浊度去除率分别高达89%和92%),相同实验环境下混凝净化效能依次为:PAC(聚合氯化铝)PFS(聚合硫酸铁)FC(三氯化铁)AS(硫酸铝)。     

改性沸石粉和聚氯化铝铁联用对藻类去除的研究

采用"改性沸石粉+聚氯化铝铁"联用的强化混凝方法,对水中藻类和浊度的去除进行了研究。考察了改性沸石粉和聚氯化铝铁(PAFC)投加量、药剂投加方式、混凝沉淀时间、pH等因素对除藻去浊效果的影响,并对比分析了强化混凝与预氯化除藻的效果及对三氯甲烷的影响。结果表明,"改性沸石粉+聚氯化铝铁"联用强化混凝方法的除藻去浊效果良好,明显优于单独投加PAFC;将改性沸石粉先于PAFC投加,在适宜的试验条件下,浊度和藻总量的去除率可分别达到85.78%和90.07%;采用强化混凝方法替代预氯化方法除藻,不仅可以提高藻类的去除率,而且不产生预氯化副产物三氯甲烷等"三致"化合物。     

聚硅酸氯化铝铁絮凝剂的合成及其特性

利用天津某钢厂的工业废料——盐酸酸洗废液、铁屑和含铝矿等为原料,合成了具有不同摩尔比的无机高分子絮凝剂聚硅酸氯化铝铁(简称PAFSC),采用Zeta电位测定法分析了产品在其水解溶液中的带电情况,并通过絮凝实验对絮凝剂的絮凝机理作了初步分析。通过处理模拟水样,与传统絮凝剂聚合氯化铝(PAC)作了对比实验,结果表明,在投加量相同的情况下,PAFSC具有较高的除浊能力,对开发研制高效、稳定、价廉的无机高分子絮凝剂提供依据。     

Size fractionation characterisation of removed organics in reverse osmosis concentrates by ferric chloride

Reverse osmosis membrane separation is the leading method for manufacturing potable purified water. It also produces a concentrate stream, namely reverse osmosis concentrates (ROC), with 10-20% of the water, and almost all other compounds. One method for further treating this stream is by coagulation with ferric chloride. This study evaluates removed organics in ROC treated with ferric chloride. Fractionation with ultrafiltration membranes allows separation of organics based on a nominal molecular weight. A stirred cell system was applied for serial fractionation to classify organic compounds into six groups of < 0.5 kDa, 0.5-1 kDa, 1-3 kDa, 3-5 kDa, 5-10 kDa and > 10 kDa. The study found that raw ROC is rich in low molecular weight compounds (< 1 kDa) with almost 50% of the organics. These compounds include soluble microbial products (SMPs) and smaller humic and fulvic acids as indicated by fluorescence scanning. Conversely, colour was mostly contributed by medium to large molecules of humic and fulvic acids (> 0.5 kDa). Organics and colour were reduced in all molecular groups at an optimum treatment dose 1.48 mM FeCl3 and a pH of 5. However, ferric seemed to effectively remove colour in all size ranges while residual nitrogen was found mostly in the < 1 kDa sizes. Further, the fluorescence indicated that larger humic and fulvic acids were removed with considerable SMPs remaining in the < 0.5 kDa.     

净水厂应对突发乙苯污染的应急处理中试研究

乙苯是净水厂原水突发水质污染的高风险物质之一.通过中试研究了应对原水突发乙苯污染的应急处理工艺.结果表明,常规工艺难以去除水中乙苯,向原水中投加粉末活性炭(PAC)与强化常规工艺联用可有效去除水中乙苯,保证处理后水质达到《生活饮用水卫生标准》(GB 5749-2006)要求;PAC与原水混合阶段是乙苯去除的主要阶段,去除率为78.9％～97.4％,强化常规工艺可进一步去除水中低浓度乙苯,颗粒活性炭滤柱作为安全余量,是水质安全保障的最后关口.基于中试结果,给出了应对原水突发乙苯污染时PAC对乙苯的吸附能力.