FeCl3和PAC对SBR工艺运行的影响研究

本文分别向两个按A/O方式运行的SBR反应器中投加一定量三氯化铁(FeCl_3·6H_2O)和聚合氯化铝(PAC),投加量为5mg/L、10mg/L、15mg/L、20mg/L,通过检测出水的TP、COD、NH_3-N、TN四项指标,对比四项指标的去除效果来考察FeCl_3和PAC这两种金属盐混凝剂对活性污泥系统处理生活污水的强化效果。结果表明,投加这两种混凝剂后反应的除磷果较好,投加量在20mg/L时,投加FeCl_3和PAC的系统对TP的平均去除率较空白组分别提高了55.6%和37%。对有机物的去除也有一定强化作用,对COD的平均去除率较空白组分别提高了40%和26.7%。但对氮处理效果提升不明显,出水NH_3-N和TN的浓度与空白对照组较为接近。     

聚合氯化铝在气浮工艺中的应用

采用阳离子助滤剂PAC代替阴离子助滤剂PAM的方法,解决了气浮处理的微气泡问题,提高了滤后水水质.通过小试和中试对两种助滤剂的助滤效果、药剂的安全性以及经济成本做了分析.与单独投加16 mg/L FeCl3相比,投加12.0 mg/L FeCl3和0.25 mg/L PAC能满足出水浊度的要求(＜0.3 NTU),且每千吨水药剂成本可节省4.20元.但投加助滤剂会降低滤池的运行周期.     

丹江口水库水低温低浊期混凝剂优选

针对低温低浊时期丹江口水库水,通过混凝沉淀烧杯试验,对水厂普遍使用的3种混凝剂三氯化铁（FeCl3）、聚合氯化铝（PAC）和硫酸铝（AS）的投加量与沉淀时间进行优选.结果表明,在试验范围内,FeCl3和PAC投加量与余浊有很强的负相关性,在投加量为12 mg/L时余浊最小,分别为0.38和0.30 NTU,明显优于AS;混凝剂投加量与UV254去除效果高度正相关,混凝剂对UV254去除作用强弱关系为PAC＞AS＞FeCl3,投加量为12 mg/L时去除率最高,分别为59％,57％和52％;投加FeCl3和PAC所形成的絮体沉淀速度快,在20～ 30 min时即可完全沉淀,而投加AS形成的絮体所需沉淀时间在40 min以上.最后在中试系统对最优混凝剂PAC投加量与浊度和UV254之间的关系进行了适应性检验,结果表明适应性良好.     

长江水源水质特点与混凝剂的选择研究

对比了长江水源和滦河水源的水质,对三氯化铁和聚合氯化铝的混凝过程进行了粒径分析。试验结果表明,长江水源的特点为低浊、低有机物,单独发挥PAC的电中和作用或FeCl3的卷扫网捕作用效果均较差。综合2种混凝剂的优势,采用先FeCl3后PAC的混合投加方式,能实现良好的混凝效果。     

强化混凝处理高藻水效果的研究

针对高藻期原水的特点,采用复配混凝剂并进行烧杯试验对复配混凝荆方案进行了优化,结果表明,无论聚合氯化铝(PAC)与FeCl3复配还是聚合氯化铝铁(PAFC)与FeCl3复配,混凝反应后的沉淀出水浊度都明显低于单独投加FeCl3,并且pH值能稳定在7.5以上.在总投加量相同的情况下,先投PAFC或PAC再投FeCl3的投药顺序最优;PAFC和FeCl3复配投加的最佳质量比为3:1,PAC和FeCl3复配投加的最佳质量比为1:2;投加间隔时间为5～20 s.采用复配混凝剂的水处理成本至少低于单独投加三氯化铁30%.     

高藻期引滦原水处理工艺的优化研究

针对偏碱性的高藻引滦原水,进行了预氧化除藻、混凝及助凝等工艺优化研究.结果表明,在预氧化接触时间为30 min的条件下,当Cl投量为0.5 mg/L、PAC投量为25 mg/L时,其除藻效果要明显好于ClO2和FeCl3,组合、Cl2和PAC组合及Cl2和FeCl3组合的,且再投加0.2mg/L的助凝剂HCA,则除藻效果会更好;ClO2对原水的pH可起到一定的调节作用,有利于提高后续的混凝效果,同时水中较高的余氯还可省去实际生产中滤前加氯消毒操作.因此采用ClO2作预氧化除藻剂、PAC作混凝剂、HCA作助凝剂比较适用于高藻期引滦原水的处理.     

混凝/微滤用于反渗透海水淡化的预处理

考察了混凝/微滤工艺用于反渗透海水淡化预处理的可行性,并通过调整FeCl3和粉末活性炭(PAC)投量来确定最佳运行条件。结果表明,当FeCl3投量为2.5mg/L(以Fe3 计)、PAC耗量为40mg/L时处理效果最好,出水浊度<0.1NTU,污泥淤塞指数SDI<1.5,CODMn平均去除率为24%,满足反渗透的进水水质要求。此外,混凝及PAC的吸附作用可使海水中粒径<0.22μm的颗粒物变大,从而被微滤膜截留,这是出水水质良好的保证。     

混凝-超滤组合工艺运行优化研究

采用混凝/浸没式超滤组合工艺对深圳某原水进行中试研究,从有机物去除和膜污染控制两方面对聚合氯化铝(PAC)投加量和膜池曝气强度进行了优化。结果表明,膜池气水比为12∶1,PAC投加量为0、3、4 mg/L时,Zeta电位绝对值逐渐减小,颗粒数和COD Mn去除效果增强,继续增加PAC投加量到5 mg/L,则Zeta电位绝对值增大,颗粒数和COD Mn去除效果变差。PAC投加量为4 mg/L,膜池气水比为(7.5∶1)、(9∶1)、(12∶1)时,Zeta电位绝对值逐渐减小,颗粒数和COD Mn去除效果逐渐增强,继续增大气水比到15∶1,则Zeta电位增大,颗粒数和COD Mn去除效果变差。PAC的投加和膜池曝气可减缓不可逆膜污染,增加PAC投加量可提高DOC去除率,降低单周期TMP增幅;提高曝气强度会降低DOC去除率,降低单周期TMP增幅。     

低温低浊水处理试验研究

以苏州护城河水为研究对象,比较了PAC、PAFC及PAC+PAM的组合投加方式对低温低浊水的处理效果。试验表明,PAC的试验效果略好与PAFC。当PAC的投加量为65mg/L时,水中浊度的去除率为71.71%。投加PAM可有效降低PAC的投药量,当PAC的投加量为33mg/L,PAM的投加量为0.5~1.0mg/L时,出水浊度稳定在2.50NTU左右。     

投加粉末活性炭对MBR中膜污染的影响

考察了投加粉末活性炭(PAC)对MBR中污泥混合液特性和膜污染的影响,并探讨了影响机理.结果表明,PAC的投加使污泥絮体平均粒径从53.25μm增至85.24 μm;混合液中的溶解性微生物代谢产物(SMP)含量与污泥比阻之间具有很好的正相关性,投加PAC可降低混合液中的SMP含量(平均值从87.17 mg/L降至65.54 mg/L),进而降低了污泥比阻值,减轻了膜孔堵塞程度,增加了膜的透过性,减缓了凝胶层污染速度,从而可有效减轻膜污染,延长膜组件的运行周期.     

微生物和化学絮凝剂复配形成絮体的分形特征

将微生物絮凝剂分别与无机絮凝剂AlCl3和FeCl3复配,考察了在不同配比条件下处理高浊度和低浊度水时所形成絮体的分形特征。结果表明,对于高浊水,当微生物絮凝剂与AlCl3的投量分别为10mL／L和2mL／L,或微生物絮凝剂与FeCl3的投量分别为10mL／L和0．5mL／L时,出水水质稳定且处理效果最优;处理低浊水时,若微生物絮凝剂与AlCl3复配则其最佳投量分别为5mL／L和1mL／L,若与FeCl3复配则其最佳投量分别为5mL／L和0．25mL／L。无论处理高浊水还是低浊水,处理效果及稳定性达最优时絮体的分形维数均在1．4-1．6之间。     

UV/Fenton法处理LCD清洗废水的后续工艺研究

简要评价了UV／Fenton法处理液晶显示屏清洗废水的效果，并对其出水的后续处理工艺做了进一步的研究。结果表明：UV／Fenton法能有效降解液晶显示屏清洗废水中的有机物，在合适的反应条件下，能使废水的COD由1468mg／L降至99mg／L，但出水的浊度和色度仍较高。将UV／Fenton法处理出水的pH值调至7左右，配合投加PAC和PAM，反应后静沉20—30min，出水浊度、色度和残余铁离子浓度均大大降低，达到了理想的出水效果。PAC、PAM的适宜投量分别约为10mg／L和0．4mg／L。     

富含高岭土的矿井水处理中存在的问题及应对措施

针对某煤矿富含高岭土的矿井水难以处理的问题,对絮凝剂PAM和PAC的选用及最佳投量进行了试验。结果表明:阳离子PAM的絮凝效果显著优于阴离子、非离子PAM的;原采用的普通型PAC配合PAM不能有效去除高岭土颗粒,而高效液体型PAC在投加量仅为普通型PAC的1/3的条件下,处理出水浊度可降至4.2～8.4 NTU。因此,实际工程确定选用阳离子PAM和高效液体型PAC药剂,投加量分别为0.25、50 mg/L,处理效果得到了显著提高,但反渗透进水SDI值仍常有超过3的情况出现。为此,在一级过滤泵前增加二次絮凝工艺(投加3～5 mg/L的PAC),保证反渗透进水SDI值稳定在3以下,达到了设计要求。     

Removal of organic matter from water by PAC/UF system

The laboratory-scale ultrafiltration (UF) experiments were conducted to determine the effect of the presence of powdered activated carbon (PAC) on the UF process performance, in terms of flux decline and the possibilities of membranes cleaning during backwashing. Poly(vinylidene fluoride) membranes formed by the phase inversion technique were used in the UF experiments. A model solution was prepared as a mixture of humic acids (HA) and phenol in concentration of 10 and 1 mg l(-1), respectively. Commercial powdered activated carbons CWZ 11 and CWZ 30 (Gryfskand Sp. z o. o., Hajnówka, Poland) were used as the adsorbents. PAC dosage was in the range of 10-100 mg PAC l(-1). The process was carried out in the cross-flow system. It was found that PAC addition to the distilled water leads to a small drop in the permeate flux, regardless of PAC dose and its type. Although PAC particles are too large to block the membrane pores inside, they deposit on the membrane surface and partially can plug the surface pores. The experimental results demonstrate that the backwashing process applied in combined PAC/UF system was especially effective when PAC dosages were <20mg PAC l(-1). However, a similar permeate flux was maintained for all carbon dosages used and reached the value of about 1 m3 m(-2) d(-1). Moreover, no further drop in the permeate flux for PAC addition to the solution containing foulants (HA) was observed. Effectiveness of the removal of HA and phenol from the model solutions was also investigated. In the PAC/UF system HA were removed in about 90%, whereas the complete removal of phenol was achieved for PAC dosage equal to 100 mg l(-1).     

Virus removal by iron coagulation-microfiltration

This study was undertaken to determine virus removal efficiency by iron coagulation followed by microfiltration (MF) in water treatment using the MS2 bacteriophage (25 nm diameter) as a tracer virus. Results from these bench-scale studies were used to propose a mechanism for virus removal by iron coagulation–MF. Ferric chloride was used as coagulant, and the dosages were 0, 2, 5, and 10 mg/L as Fe(III) with pH adjusted during mixing to 6.3, 7.3 and 8.3. In the absence of iron-coagulation and with less than 2 mg/L Fe, MF alone achieved less than a 0.5 log removal of MS2 virus. However, iron-coagulation pretreatment dramatically improved virus removal, especially in the 5–10 mg/L Fe dose range, ultimately achieving more than 4-log removal at pH 6.3 with 10-mg/L Fe dose. For the 5 and 10 mg/L Fe dosages, decreasing pH in the 8.3–6.3 range resulted in significantly greater virus removal. For 0 and 2 mg/L iron dosages, decreasing pH in the 8.3–6.3 range also improved virus removal, but to a lesser extent. The experimental data indicates negatively charged MS2 viruses first adsorbed onto the positively charged iron oxyhydroxide floc particles before being removed by MF. MS2 viruses were not inactivated in iron or aluminum coagulation as evidenced by the fact that their concentrations before and after coagulation, settling, and re-suspension of the coagulated sludge were not statistically different.     

粉末活性炭对马拉硫磷的吸附性能研究

以马拉硫磷作为突发性污染物,考察了粉末活性炭对其的吸附效果。试验结果表明,粉末活性炭对纯水和滤后水中的马拉硫磷均具有较好的去除效果,对前者的去除效果更为明显,去除率随活性炭投加量的增加而升高。当马拉硫磷浓度为1.25 mg/L,纯水、滤后水中的活性炭投加量分别为12.0和20 mg/L时,反应120 min后马拉硫磷剩余浓度均低于0.25 mg/L。对滤后水而言,药剂费用约为0.06～0.08元/m3。     

强化混凝工艺处理滦河低温低浊水的试验研究

结合现有的中试试验系统,开展了强化混凝工艺的试验研究,结果表明,在该水质期,混凝剂PAC对浊度和CODMn的去除效果较优于混凝剂FeCl3;然而在满足出水浊度和CODMn要求的情况下,每处理单位水体PAC混凝药剂费用远高于FeCl3;使用NaSiO3与FeCl3混合液作为混凝剂时,适当增大混合液中NaSiO3的比例有利于提高常规工艺处理效率。     

船厂二级生化出水的回用技术应用研究

通过小试模拟船厂二级生化出水的中置式混凝沉淀工艺运行过程,研究了PAC和PAM投加量对出水水质的影响。结果表明,PAC和PAM最佳投量分别为40和0.3 mg/L。根据小试结果进行中试投药,结果显示NaClO的最佳投量为10 mg/L、PAC和PAM最佳投量与小试一致;中试对COD的去除率要高于小试,且出水水质达到《城市污水再生利用城市杂用水水质》(GB/T18920—2002)与《城市污水再生利用景观环境用水水质》(GB/T 18921—2002)水质标准;除总氮外,中试出水其余指标均达到《地表水环境质量标准》(GB 3838—2002)的Ⅳ类水质要求,且部分指标达到Ⅰ类和Ⅲ类水质要求。回用水处理总价为0.65元/t,厂区自来水费为2.38元/t,中水回用装置流量按30 t/h来计,则企业每年可节约自来水量为26.3×104t,每年将节省45.5万元;同时还可以减排污水量为26.3×104t,削减COD量为10.52 t、NH3-N量为0.39 t、TP量为0.26 t。     

Chemical coupling of photocatalysis with flocculation and adsorption in the removal of organic matter

An experimental investigation was made to study the effects of chemical coupling of flocculation and adsorption with photocatalysis in treating persistent organic pollutants in wastewater. The photocatalysis alone showed initial reverse reaction when titanium oxide (TiO(2)) was used in catalysis. The effect of the pretreatment of adsorption with powdered activated carbon (PAC) on photocatalysis was studied. The results showed that PAC adsorption followed by photocatalysis was not effective in alleviating reverse reaction. On the other hand, when PAC and TiO(2) were added simultaneously, the reverse reaction was eliminated. Further, the organic removal was also improved by simultaneous PAC and TiO(2) additions. When flocculation with ferric chloride (FeCl(3)) was used as pretreatment, the organic removal efficiency was superior. The initial reverse reaction was also eliminated/minimized. However, inadequate doses of FeCl(3) (less than 30 mgl(-1)) resulted in initial reverse reaction and inferior DOC removal.