常规混凝沉淀工艺对阴离子表面活性剂的去除研究

随着阴离子表面活性剂(LAS)在民用和工业上的广泛应用,由此带来的水污染问题也日益加剧,对供水安全造成了很大威胁。针对目前大部分水厂仍采用混凝沉淀常规水处理工艺,考察了常规混凝沉淀工艺对LAS的去除效果。以Al2(SO4)3,PAC,FeCl3,PFS为混凝剂,非离子PAM为助凝剂进行了试验,结果表明混凝沉淀对LAS有一定的去除效果,而且有机物和LAS的去除有一定相关关系。但浊度与LAS的去除相关性较差。试验条件下对于LAS去除最佳混凝方案是投加量为40 mg/L的FeCl3。相同水质条件下铁盐混凝剂在除浊、除有机物和除LAS方面优于铝盐混凝剂。pH和水温对LAS的去除有一定影响,较低的pH和较高的水温均有利于LAS的去除。     

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。     

采用活性炭强化常规处理原水突发油类污染的研究

中试研究表明,常规处理(混凝—沉淀—过滤)可以将含油约为10mg/L的原水处理达标,并且除油率不受混凝剂投加量的影响。油污染浓度为7.2～18mg/L的原水经混凝沉淀去除的效率基本相同。20mg/L的油污染仅通过常规处理无法达标,需采用投加粉末活性炭(PAC)的强化混凝或颗粒活性炭(GAC)的强化过滤,即投加40mg/L的PAC,或在过滤阶段铺40cmGAC层的炭砂滤柱。KMnO4和Cl2的预氧化对除油效果无影响。     

模拟突发汞污染原水应急处理试验研究

采用烧杯试验考察了常规混凝、预加石灰乳混凝以及硫化钠沉淀联合强化混凝对模拟突发性汞污染原水中汞的去除效果。通过硫化钠投加量、pH、2种混凝剂和3种助凝剂及其投加量对除汞效果的影响试验,优化了硫化钠沉淀联合强化混凝法除汞。结果表明,常规混凝汞去除率为23.5%～31.8%;预加石灰乳混凝的汞去除率为32.8%～79.8%;硫化钠沉淀联合强化混凝的除汞效果最好,平均去除率大于90%。硫化钠的最佳投量比为1∶2(Hg2 ∶Na2S.9H2O),在过量200%以下出水硫离子均不超标。pH在8以上可确保硫化钠充分发挥作用。PAC最佳投加量为20mg/L,PAM最佳投加量为0.1mg/L。为期30天规模为4m3/h的中试验证了优化后的硫化钠沉淀联合强化混凝应急处理方法对不同汞污染程度的原水的除汞效果与小试基本一致。用硫化钠沉淀联合强化混凝应急除汞,在汞超标100倍以下,过滤出水可达标,在汞超标60倍以下,沉淀出水可达标。处理费用为0.02588元/m3。     

南水北调滤后水残余铝的影响因素试验研究

为控制残余铝浓度,以南水北调水为原水,研究混凝剂种类及投加量、助凝剂投加比例、pH值调节方式及pH值、沉淀时间等因素对滤后水中残余铝的影响。从除浊效果、UV254去除效果及滤后水残余铝浓度3个方面进行了试验研究,结果表明:混凝剂为聚合氯化铝(PAC)、最佳投加量为25 mg/L、助凝剂为活化硅酸、混凝剂与助凝剂投加比例为5∶1、原水pH值为7.5、沉淀时间为30min时,浊度和UV254均有较好的去除效果,同时可控制残余铝浓度远低于国标规定的浓度限值(0.2 mg/L)。     

混凝-气浮除藻工艺中混凝剂的选择

通过对比聚氯化铝、硫酸铝、聚硫酸铁和氯化铁的混凝—气浮处理效果,选择最合适的混凝剂进行后续研究。试验结果表明:对于藻密度1.6×10~(10)个/L左右的铜绿微囊藻原水,经处理后取得相近的出水效果时,聚合混凝剂比无机盐混凝剂投药量少很多,聚氯化铝比硫酸铝的用量减少70%以上,聚硫酸铁比氯化铁用量减少30%以上;对于铜绿微囊藻原水,铁系混凝剂对浊度、TOC的去除效果优于铝系混凝剂;铝系混凝剂对色度、藻密度的去除优于铁系混凝剂。     

复合混凝法处理高炉煤气洗涤水试验

以包钢高炉煤气洗涤水处理系统为研究对象,通过静态混凝沉淀试验,确定复合混凝剂最佳配比为聚合硫酸铁10 mg/L、聚丙烯酰胺0.1 mg/L、石灰25～250 mg/L(调节pH值为8.5左右).处理后,出水清澈透明、浊度低,絮体大而密实、沉降速度快,水质能够达到回用水水质指标要求.     

沉淀-气浮组合工艺处理低浊高藻水试验研究

针对北方地区地表水夏天高藻冬天低温低浊的水质特点,采用沉淀-气浮组合工艺进行了低浊高藻水净水效果的中试研究。通过试验,首先确定了混凝剂PAFC投加量4.5mg/L、进水流量0.6m~3/h和回流比8%的试验条件。在此试验条件下,沉淀-气浮组合工艺的平均出水浊度为0.75NTU,去除率达95.2%;出水的颗粒数总量4 800个/mL,去除率达95.9%,且对不同粒径区间颗粒数去除效果基本一致;出水COD_(Mn)为3.95mg/L,去除率为41.3%,出水藻类数量270万~900万个/L,去除率达96%;臭味物质2-MIB和GSM的含量均小于6×10~(-6) mg/L,低于国标参考值。试验结果表明,沉淀-气浮组合工艺对浊度、颗粒数、藻类、臭味物质等去除率较高,对CODMn有一定的去除效果,低浊高藻水适合采用沉淀-气浮组合工艺进行处理。     

含腐殖酸低浊原水的改性凹土强化混凝效果分析和参数确定

研究了改性凹土联合聚氯化铝强化混凝耦合去除浊度和腐殖酸的效果。试验原水条件为腐殖酸浓度10mg/L,浊度为(30±1)NTU。采用静态混凝搅拌试验,考察了聚氯化铝和改性凹土的混凝沉淀时间、复配投加量、pH、投加顺序、搅拌速率等工艺参数对腐殖酸和浊度耦合去除效果的影响。结果表明,在强化混凝中,当聚氯化铝投加量为15mg/L,改性凹土投加量为30mg/L,沉淀时间30min,pH=7时,腐殖酸和浊度的同步去除率分别达到95.5%和96.8%,对比单投加聚氯化铝混凝工艺,聚氯化铝投加量可降低25%,并减少沉降时间。     

Fenton氧化深度处理柠檬酸生产废水

采用Fenton氧化深度处理柠檬酸废水通过正交试验和单因素轮换试验,分析pH、H_2O_2投加量、反应时间、H_2O_2/FeSO_4四个主要因素对COD_(Cr)去除效果的影响。试验结果表明影响效果从大到小依次为pHH_2O_2/FeSO_4反应时间H_2O_2投加量,单因素试验确定最佳的反应条件为:pH为3.5、反应时间为2 h、30%H_2O_2投加量0.9 mL/L,FeSO_4用量为223.4 mg/L,此条件下COD_(Cr)去除率达到约75%。氧化去除COD_(Cr)过程符合准一级反应,表观速率常数0.012 9 min~(-1),设计连续流全混反应器中停留时间为2 h。在最佳药剂投加量下,中试连续运行出水COD_(Cr)40 mg/L,实际出水COD_(Cr)与理论拟合值接近。     

地下水除铁除锰水厂铁泥处理试验研究

通过试验,探讨了地下水除铁除锰水厂内铁泥的沉淀、脱水性能及其影响因素。结果表明,随着含固率的降低,铁泥沉淀速度提高;投加絮凝剂后,铁泥成层沉淀速度显著增加,并且在一定范围内,随着絮凝剂投加量的增加而增加;有机高分子絮凝剂CPF的助沉效果明显优于无机高分子絮凝剂PAC;随着pH的提高,铁泥沉淀效率降低,当pH为9.57时,铁泥基本上不沉淀;温度越低, 铁泥沉淀速度越慢;投加高分子絮凝剂,降低pH,可改善铁泥的脱水性能。     

石灰软化法处理地下水源水硬度试验研究

采用石灰软化法处理某地下水源水硬度,结果表明,当石灰投加量为220mg/L,pH为8.7～8.9时,可使原水硬度和碱度分别由300mg/L和250mg/L降至115mg/L和80mg/L以下,去除率分别为61.7%和68%,沉淀和过滤对硬度去除效果影响不大;投加石灰后出水浊度明显升高,投加PAC(聚氯化铝)40mg/L,并与常规工艺联用,可使出水浊度稳定降低至0.15～0.65NTU;试验证明"石灰+PAC+常规工艺"能有效去除水中硬度和浊度,出水煮沸后不再生成沉淀和悬浮物,符合现行《生活饮用水卫生标准》(GB 5749—2006)和用户使用要求,石灰软化法药耗成本估算为0.246元/m3。     

Fenton试剂处理选矿废水的试验研究

研究用Fenton试剂处理含苯胺黑药(二苯胺基二硫代磷酸)模拟废水和实际选矿废水,分别考查了反应初始pH值、Fe2+浓度及H2O2用量对COD去除率的影响。结果表明:氧化时间为10 min,反应初始pH值为4,ρ(Fe2+)=1.83 g/L,ρ(H2O2)=5.55 g/L,模拟废水苯胺黑药的质量浓度为300 mg/L时,COD去除率达到83.6%;对于实际废水,当ρ(Fe2+)=50mg/L,pH值=3.5,ρ(H2O2)=1800mg/L时,出水ρ(COD)从1000mg/L降到32 mg/L,COD去除率为96.8%,达到废水排放标准,药剂成本估计为每处理1 m3废水需要费用18元。     

Fenton氧化法深度处理制革废水生化出水试验研究

采用Fenton氧化法深度处理以制革废水为主的园区生化处理出水,试验表明:影响Fenton氧化的因素从大到小依次为H2O2投加量、Fe2+浓度、pH、反应时间。当进水CODCr平均为116.6mg/L时,在H2O2投加量50mmol/L、Fe2+投加量10mmol/L、pH为3、反应时间60min的最佳条件下,出水CODCr平均为31.7mg/L;在H2O2投加量25mmol/L、Fe2+投加量7.5mmol/L、pH为5、反应时间40min的经济运行条件下,出水CODCr平均为46.6mg/L。经济条件下的运行成本比最佳条件下的运行成本可节约2.3元/m3。     

Arsenic removal by ferric-chloride coagulation--effect of phosphate, bicarbonate and silicate

Jar tests with synthetic water were carried out in order to investigate the effect of phosphate, bicarbonate and silicate on arsenic removal efficiency by in-situ formed ferric hydroxide. Above 12 mg C/L inorganic carbon concentration, the adverse effect of bicarbonate was definite, and resulted in higher remaining arsenic concentration. At all pH values (7.5-7.8) and coagulant dosages (0.84-3.00 mg/L Fe) tested, the negative effect of phosphate on arsenic removal was also evident. In the presence of silicate small ferric-hydroxide colloids were formed, which were able to go through the 0.45 microm pore-size membrane. Compared to silicate-free systems, 2.5-3.5 times higher coagulant dose was needed to achieve the target arsenic concentration in the presence of 14-23 mg/L Si. At higher pH values the adverse effect of silicate was even more significant. All data were merged and multiple linear regression analysis was carried out in order to build up a robust model to predict the residual arsenic concentration if the raw water contains 50-60 microg/L initial arsenic concentration. The estimation was based on the following variables: PO4-P concentration, final pH, Si concentration, Fe(III) dose. The most important influencing factors proved to be the silicate concentration and applied coagulant dosage.     

Fenton试剂和氧化镁联合处理化学实验室排水

利用Fenton试剂和氧化镁联合处理化学实验室排水,探讨联合处理的最佳工艺条件。结果表明:在pH值为5时,加入15g/L过氧化氢和2g/L硫酸亚铁搅拌反应30min,废水的COD去除率达82.1%,经二级处理后排水中的COD去除率达96.4%;加入15g/L氧化镁后废水中的重金属离子去除率达到99.8%。     

微絮凝超滤对微污染源水中氨氮去除的试验研究

采用微絮凝超滤工艺对微污染水中氨氮的去除进行了试验研究。结果表明,该工艺能有效地去除水中的氨氮,验证了有机物含量对氨氮去除的影响,同时得出了采用铝盐和铁盐混凝剂的最佳投加量为2.5 mg/L,最佳pH值为5.5~6.0。     

Phosphorus removal from synthetic and municipal wastewater using spent alum sludge.

In the present study, phosphorus removal was studied using as coagulant spent alum sludge from a water treatment plant of EYDAP (Athens Water Supply and Sewerage Company) and compared to alum (Al2(SO4)3.18H2O), iron chloride (FeCl3.7H2O), iron sulfate (Fe2(S04).10H2O) and calcium hydroxide (Ca(OH)2) at a constant pH (equal to 6).The comparison was based on their efficiency to remove phosphorus in synthetic wastewater consisting of 10 mg/L P as potassium dihydrogen phosphate and 50 mg/L N as ammonium chloride, The experiments were carried out using a jar-test apparatus and the measurements were performed according to the Standard Methods for the Examination of Water and Wastewater. Pure alum, iron chloride and iron sulfate were much more efficient in phosphorus removal than the spent alum sludge but in the case of calcium hydroxide, phosphorus removal was very low in pH = 6. Specifically, orthophosphate were totally removed by alum using 15 mg/L as Al, by alum sludge using 75 mg/L as Al and by FeCl3.7H2O or Fe2(SO4).10H2O using 30 mg/L of Fe while in the case of calcium hydroxide P removal was actually zero. pH measurements showed that the uptake of phosphates is associated to the release of OH ions in the solution and that the end of P uptake is accompanied by the stabilization of pH. Finally this spent alum sludge was tested on municipal wastewater and proved to be effective as apart from phosphorus it was shown to remove turbidity and COD.     

Treatment of oilfield wastewater by Fenton's process.

A combination of coagulation and Fenton's process was used for the removal of total oxygen carbon (TOC) from oilfield wastewater. Compared with aluminium sulfate, ferric coagulant had better TOC removal efficiency at the same mass dosage. In Fenton's process, the effect of H2O2 and Fe2+ dose on the removal of TOC was studied. The optimum conditions required for TOC removal were an Fe3+ concentration of 40-50 mg/L, an H2O2 dose of 50 mmol/L and an Fe2+ concentration of 1.0 mmol/L. GC-MS chromatographic analysis indicated that most of the alkyl hydrocarbons of carbon numbers < 21 were removed in the first minute of Fenton's process mainly through adsorption. Alkyl hydrocarbons and phenols were oxidized almost completely following 120 min of treatment. The pathway of newly formed intermediates in Fenton's process was proposed on the basis of the GC/MS chromatogram.     

Fenton试剂在微波条件下处理稻壳热解发电含酚废水的试验

采取试验手段,研究在微波条件下用Fenton试剂处理含酚废水的效果,探讨H2O2质量浓度、FeSO4质量浓度、pH值、反应时间和微波功率等因素对稻壳热解发电废水中COD、挥发酚及色度去除率的影响,并进行不同条件下Fenton反应的对比试验。结果表明,在微波条件下,Fenton试剂能快速降解含酚废水,处理后水样的COD去除率超过73%,挥发酚去除率超过99%,色度去除率接近50%。该含酚废水的最佳处理条件是:H2O2质量浓度为1500 mg/L,FeSO4质量浓度为100 mg/L,pH值为3,反应时间为10 min,微波功率为400 W。