新型复合多层滤料滤池处理微污染水的过滤技术研究

以内江市沱江受微污染源水为研究对象,比较三种生物活性滤料滤池(两种新型复合多层滤料滤池和瓷砂-石英砂双层滤料滤池)的挂膜情况和稳定运行期的处理效果.研究结果表明:包含惰性和活性滤料(由极性和非极性滤料复合而成)并在下部设有一定厚度的石英砂出水浊度保护区的新型复合多层滤料滤池在充氧条件下,对CODMn的去除率可达22.4%～29.2%,对氨氮的去除率可达57%～92%,其出水水质优于国家生活饮用水卫生标准,具有较好的处理效果.     

臭氧/复合滤料生物滤池深度处理饮用水试验研究

利用陶粒/颗粒活性炭组成新型复合滤料,同时结合臭氧氧化作用深度处理饮用水,考察了臭氧/复合滤料生物滤池深度处理饮用水的效果及有关参数对处理效果的影响.试验结果表明,该生物滤池对浊度、UV254、CODMn、 NO2--N的平均去除率分别为69.1%、43.2%、65.4%和75.8%,对NH4+-N的平均去除率可高达91.2%.随着空床接触时间的延长,对各污染物的去除率逐渐增大,综合对各指标的去除情况及经济因素,空床接触时间以15 min左右为宜.对污染物的去除主要集中在滤池上部,去除效果的变化趋势与溶解氧浓度沿滤料层的变化趋势基本一致.该生物滤池对污染物的去除效果与进水污染物浓度有关,经拟合,对CODMn和NH4+-N的去除率与进水CODMn浓度呈对数关系,当CODMn为0-20 mg/L时,随着进水CODMn浓度的增大,对CODMn的去除率逐渐增大,而对NH4+-N的去除率逐渐降低.     

复合生物活性滤料滤池的性能研究

采用由惰性和活性滤料 (由极性和非极性滤料复合而成 )复合构成的新型生物活性滤料滤池进行过滤试验。结果表明 ,该滤池对氨氮的去除率 >90 % ,对CODMn的去除率 >4 0 % ,使Ames试验致突变性降低约 1/ 3左右 ,其出水水质满足国家《生活饮用水卫生标准》(GB 5 74 9— 85 ) ,具有较好的处理效果。     

天然有机物对铁锰复合氧化膜去除氨氮的影响

利用中试系统和静态试验,以富里酸为对象,研究天然有机物对石英砂滤料表面负载的铁锰复合氧化膜去除地表水中氨氮的影响。中试结果表明,当富里酸浓度在0～10 mg/L时,富里酸对氨氮的去除没有明显影响,氨氮去除率均高于95. 2%;当富里酸浓度在10～20 mg/L时,氨氮去除率降至65. 4%,甚至出水氨氮超标。静态试验结果表明,氨氮降解过程符合一级反应动力学,相关系数R2 0. 9,ln(C_0/C_t)与反应时间t有很好的线性关系,随着富里酸浓度的增加,氨氮降解速率k_1值逐渐降低,其中空白的k_1值为0. 012 67 min~(-1),富里酸浓度为5、10和20 mg/L时k_1值分别为空白的78. 6%、63. 4%和57. 6%,即富里酸对氨氮的氧化过程有不利的影响。FTIR光谱分析结果证实了富里酸在铁锰复合氧化膜的表面吸附,且富里酸的羧基离子和铁锰复合氧化膜的表面羟基在吸附过程中起着重要作用。     

离子色谱法检测饮用水中的溴酸盐

目前农村很多联村水厂、自建设施供水厂以及瓶装纯净水厂以臭氧为消毒方式,自然水体中的溴元素很容易被臭氧氧化为溴酸盐,美国环保局和世卫组织把溴酸盐列为"可能的致癌物"。我国2007年7月1日开始实施的《生活饮用水卫生标准》(GB5749-2006)中将溴酸盐列为水质常规指标并规定限值为0.01mg/L。本实验采用的是《生活饮用水标准检验方法》(GB/T5750-2006.10)中推荐的离子色谱法—碳酸盐系统淋洗液,本实验采用ICS-1000型离子色谱仪,通过考察改变仪器条件(如:淋洗液浓度、流速、定量环容量等),分析实验结果,确定色谱条件为:Dionex Ionpac AS23分离柱和Ionpac AG23保护柱;SRS 3004-mm阴离子抑制器;淋洗液浓度为0.45mmol/L Na_2CO_3和0.08mmol/LNa HCO_3混合液;淋洗液流速为1.0m L/min;进样体积为1m L。方法检出限为0.005mg/L,检出限RSD7为3.52%,0.040mg/L的溴酸盐标准溶液RSD20为4.32%,实验检测的线性相关系数r0.999,加标回收率为90.0%~108.3%。该方法操作简单,灵敏度高,可连续自动检测等特点,可以满足国标要求。     

溴酸盐生成水平判断臭氧化工艺适用性

为利用溴酸盐生成水平判断臭氧化净水工艺在深圳地区的适用性,对该地区水库水中的溴离子浓度进行了调查,并在此基础上开展了预臭氧化和主臭氧化工艺的溴酸盐生成量研究。结果表明,水库水中的溴离子浓度为0~73μg/L(平均为22μg/L),在所调查的55座水库中,90%水库水的溴离子浓度<50μg/L;预臭氧化及主臭氧化工艺均不会使饮用水中的溴酸盐超标(25μg/L)。     

离子色谱法测定瓶装水中溴酸盐、氯酸盐和高氯酸盐

建立了离子色谱法同时测定瓶（桶）装饮用水中溴酸盐、氯酸盐和高氯酸盐的方法。选用Ionpac AS20阴离子分析柱，在线产生5～55 mmol/L KOH淋洗液，流速1.00 mL/min，柱温30℃，抑制器电流137 mA，进样体积500μL，电导检测器检测。应用该方法检测50份市售瓶（桶）装饮用水，结果表明，溴酸盐、氯酸盐和高氯酸盐在0.005～0.500 mg/L范围内线性良好，相关系数均大于0.999 0，测定结果精密度高（RSD<1.0%）；溴酸盐、氯酸盐和高氯酸盐的方法检出限分别为1.5、1.0、1.5μg/L；定量限分别为5.0、3.3、5.0μg/L；回收率分别为87.0%～101.5%、93.4%～118.0%和90.9%～114.0%。50份瓶（桶）装饮用水中，溴酸盐、氯酸盐和高氯酸盐检出率分别为40.0%、66.0%、14.0%，均未超标。该方法快速、灵敏、准确，适用于瓶（桶）装饮用水中溴酸盐、氯酸盐和高氯酸盐的同时检测。     

铁锰复合活性滤料去除冬季地表水中氨氮的效能

采用铁锰复合氧化物活性滤料滤池进行了低温高氨氮地表水处理试验研究,并与普通石英砂生物滤池进行对比。结果表明,铁锰复合氧化物活性滤料滤池对地表水中氨氮具有良好的去除效果,与普通石英砂生物滤池相比,在抗水力负荷、浓度负荷和反冲洗方面更有优势;当滤速分别为4、6、8 m/h时,铁锰复合氧化物活性滤料滤池对氨氮的平均去除率分别为97.2%、94.3%、93.5%,而相应条件下普通石英砂生物滤池对氨氮的平均去除率仅为84.1%、64.7%、58.0%;在滤速为8 m/h、滤层厚度为110 cm条件下,铁锰复合氧化物活性滤料滤池去除氨氮的最大浓度为2.30 mg/L,而普通石英砂生物滤池去除氨氮的最大浓度仅为1.50 mg/L;对浊度、有机物的去除,铁锰复合氧化物活性滤料滤池与普通石英砂生物滤池效果相当。     

臭氧/高锰酸盐控制臭氧氧化副产物

臭氧氧化过程中产生的一些副产物[如生物可同化有机碳(AOC)、溴酸盐和甲醛等]会影响供水水质安全性。采用臭氧/高锰酸盐复合氧化可在不同程度上提高对AOC的去除率,其合理的投量配比为高锰酸盐0.5mg/L 臭氧1.0mg/L,在该条件下两者的物质的量之比约为1∶8,对AOC的去除率可以提高20%～30%。复合氧化减少了溴酸盐的生成,在不同的臭氧投量情况下都可以取得20%左右的降幅。甲醛是一种典型的臭氧氧化副产物,单纯臭氧氧化后会导致甲醛浓度升高,而投加高锰酸盐可以降低这种趋势,即复合氧化可以有效地减少甲醛的生成。     

净水厂中全氟化合物分布特征及UV/SO_3~(2-)的去除机理

通过考察长江原水和南方某净水厂各单元处理工艺中5种全氟化合物(PFCs)的分布特征,分析了各单元对PFCs的去除效果,并探讨了UV/SO_3~(2-)光还原技术降解饮用水中PFCs的机理。长江原水经过净水厂处理后,总PFCs去除率为35.33%,其中混凝沉淀工艺对PFCs的去除率最高,臭氧和氯消毒工艺会造成PFCs的增加;采用波长为365 nm、功率为500 W的紫外灯激发SO_3~(2-)产生的水合电子能够降解水中的PFCs。当PFCs初始浓度为1 mg/L、SO_3~(2-)浓度为0.4 g/L、p H值为8.5时,5种PFCs的降解均符合一级反应动力学;PFDA降解的中间产物表明UV/SO_3~(2-)技术是通过逐步脱去CF2实现降解的。     

生物炭形成过程对溴酸盐和有机物的去除能力研究

含有溴离子的原水经臭氧氧化后会生成具有致癌性的溴酸盐，因此研究溴酸盐的控制对策成为饮用水处理领域的热点。通过模拟配水试验考察了新鲜活性炭向生物活性炭转化过程中对溴酸盐和有机物去除能力的变化。结果表明，活性炭滤池能有效去除溴酸盐，新炭在向生物活性炭转化的过程中滤池对溴酸盐的去除能力表现出逐渐减弱的趋势，待完全成为生物活性炭滤池后对溴酸盐的去除效果较差。不过，活性炭滤池和生物活性炭滤池对CODMn、UV254、致色有机物和CCl4都有较好的去除效果。     

Water quality factors affecting bromate reduction in biologically active carbon filters

Biological removal of the ozonation by-product, bromate, was demonstrated in biologically active carbon (BAC) filters. For example, with a 20-min EBCT, pH 7.5, and influent dissolved oxygen (DO) and nitrate concentrations 2.1 and 5.1 mg/l, respectively, 40% bromate removal was obtained with a 20 microg/l influent bromate concentration. In this study, DO, nitrate and sulfate concentrations, pH, and type of source water were evaluated for their effect on bromate removal in a BAC filter. Bromate removal decreased as the influent concentrations of DO and nitrate increased, but bromate removal was observed in the presence of measurable effluent concentrations of DO and nitrate. In contrast, bromate removal was not sensitive to the influent sulfate concentration, with only a slight reduction in bromate removal as the influent sulfate concentration was increased from 11.1 to 102.7 mg/l. Bromate reduction was better at lower pH values (6.8 and 7.2) than at higher pH values (7.5 and 8.2), suggesting that it may be possible to reduce bromate formation during ozonation and increase biological bromate reduction through pH control. Biological bromate removal in Lake Michigan water was very poor as compared to that in tapwater from a groundwater source. Bromate removal improved when sufficient organic electron donor was added to remove the nitrate and DO present in the Lake Michigan water, indicating that the poor biodegradability of the natural organic matter may have been limiting bromate removal in that water. Biological bromate removal was demonstrated to be a sustainable process under a variety of water quality conditions, and bromate removal can be improved by controlling key water quality parameters.     

Effect of medium-pressure UV irradiation on bromate concentrations in drinking water, a pilot-scale study

This study investigated the potential for bromate removal from drinking water on irradiation with medium-pressure UV lamps-a technique gaining considerable interest for drinking water disinfection. Waters from two different sources were spiked with 20microg/L of bromate and irradiated with UV fluences up to 718mJ/cm(2) utilizing a pilot-scale reactor (Calgon Carbon Corp.) at a flow of 76L/min (20 gallon/min). Essentially no removal was observed in one of the source waters. Limited bromate removal, up to 19%, was observed in the second source water at high UV fluences (696mJ/cm(2)) and a fluence-response relationship was clearly evident. All removals would be negligible at UV fluences anticipated for drinking water disinfection (< or =40mJ/cm(2)). Different water characteristics, in particular competitive absorption by nitrate and possibly DOC, were most likely responsible for the differences in bromate removal in the waters tested. The source water that did not show any removal had a higher nitrate concentration (4 vs. 0.1mg N/L) and also a higher DOC concentration (4.1 vs. 3.1mg C/L) than the other source water which showed 19% bromate removal.     

ZSM-5沸石削减臭氧氧化过程中的溴酸根生成量

分别采用超纯水、硼酸盐缓冲溶液和自来水配制含溴离子水,考察投加不同硅铝比的ZSM-5沸石对臭氧氧化过程中溴酸根生成量的削减效果及机理.结果表明,在三种不同介质中,ZSM-5沸石对溴酸根生成量的削减效果依次为:超纯水>硼酸盐缓冲溶液>自来水;硅铝比为300的ZSM-5沸石的削减效果最好,在硼酸盐缓冲溶液体系中,反应30min后可使溴酸根的生成量减少66%.硅铝比为300的ZSM-5沸石对溴离子和溴酸根均无明显的吸附作用,但可显著减少臭氧分解过程中的H_2O_2产量,这是其削减溴酸根生成量的主要原因.     

O3／BAC工艺中溴酸盐的控制

通过试验考察了活性炭、陶粒以及挂膜陶粒对溴酸盐的去除效果,分析了微生物对溴酸盐的降解作用。结果表明,在滤池以及生物活性炭滤池内成熟的微生物膜对溴酸盐有降解能力,溴酸盐去除量与水力接触时间的关系为9．16μg（L·h）。在活性炭（GAC）吸附以及微生物降解协同作用下,可以在不增加运行成本的基础上稳定、有效地控制溴酸盐。     

Biofiltration for removal of BOM and residual ammonia following control of bromate formation

Nitrification was developed within a biological filter to simultaneously remove biodegradable organic matter (BOM) and residual ammonia added to control bromate formation during the ozonation of drinking water. Testing was performed at pilot-scale using three filters containing sand and anthracite filter media. BOM formed during ozonation (e.g., assimilable organic carbon (396-572 microg/L), formaldehyde (11-20 microg/L), and oxalate (83-145 microg/L)) was up to 70% removed through biofiltration. Dechlorinated backwash water was required to develop the nitrifying bacteria needed to convert the residual ammonia (0.1-0.5 mg/L NH(3)-N) to nitrite and then to nitrate. Chlorinated backwash water resulted in biofiltration without nitrification. Deep-bed filtration (empty-bed contact time (EBCT) = 8.3 min) did not enhance the development of nitrification when compared with shallow-bed filtration (EBCT = 3.2 min). Variable filtration rates between 4.8 and 14.6 m/h (2 and 6 gpm/sf) had minimal impact on BOM removal. However, conversion of ammonia to nitrite was reduced by 60% when increasing the filtration rate from 4.8 to 14.6 m/h. The results provide drinking water utilities practicing ozonation with a cost-effective alternative to remove the residual ammonia added for bromate control.     

强化活性炭滤池过滤性能的试验研究

采用在活性炭滤池前端投加不同药剂的方法深度净化某水厂沉淀池出水,考察了不同滤池形式、聚合氯化铝(PAC)投加量和阳离子型聚丙烯酰胺(PAM)投加量对沉后水浊度的去除效果。结果表明,在下向流滤池前端投加0.3 mg/L的PAC和0.03 mg/L的PAM可以明显强化活性炭滤池的过滤效果,使出水浊度小于0.1 NTU;与砂滤池出水相比,活性炭滤池对浊度的去除率提高了16.6%,CODMn去除率提高了56%;相应的滤池水头损失增加较快,但仍可以满足运行周期不小于24 h的设计要求;滤后水中铝和溴酸盐含量均满足《生活饮用水卫生标准》(GB 5749—2006)要求。     

Ammoniacal bromamines: a review of their influence on bromate formation during ozonation

Ammonia can inhibit the formation of bromate in ozonated drinking water by reacting with free bromine (HOBr/OBr-), an intermediate in bromate formation, to form bromamines. Bromamines do not participate in bromate formation, however, they will decay due to autonomous decomposition and through reaction with ozone and hydroxyl radicals. The reaction with ozone controls the overall decay rate. This reaction also results in a net loss of ammonia from the system, leading to the possibility that all ammonia may be oxidized before the ozone residual in the water is eliminated, allowing bromate formation to resume. This paper presents a review of our understanding of bromamine chemistry and identifies areas that are not adequately understood, which may prevent an accurate estimation of ammonia's impact on bromate formation.     

臭氧消毒中溴酸盐的形成、检测与控制

用臭氧对含溴化物的饮用水进行消毒时会生成溴酸盐副产物，溴酸盐被国际癌症研究机构定为2B级（具有较高的致癌可能性）潜在致癌物。臭氧氧化溴化物生成溴酸盐要经过多步反应，控制溴酸盐生成的方法有加氨、降低pH值、投加活性炭、投加高锰酸盐和增加臭氧投加点的数量等。用臭氧消毒的最终目的是杀灭致病菌，因此如何找到臭氧、致病菌、溴酸盐消毒副产物之间的最佳平衡点还有待进一步研究。     

A method for preparing silica-containing iron(III) oxide adsorbents for arsenic removal

A method for preparing iron(III)-based binary oxide adsorbents in a granulated form for arsenic removal was studied. The key step in the method was the simultaneous generation of hydrous ferric oxide (FeOOH) sol and silica sol in situ in one reactor. This eventually led to the formation of Fe-Si complexes. The addition of silica enhanced the granulated adsorbent strength but reduced the arsenic adsorption capacity. An optimum Si/Fe molar ratio in the balance of adsorbent strength and arsenic adsorption capacity was found to be approximately 0.33. The effects of aging time, drying temperature and process pH on adsorbents were also evaluated in the study. X-ray diffraction analysis confirmed that the iron(III) oxide in the Fe-Si binary oxide adsorbents was amorphous, largely due to the retardation of the iron oxide crystallization by the presence of silicate species. The surface area of the Fe-Si adsorbents and the particle size of Fe-Si complexed suspensions were determined as well. The batch strength testing procedure introduced in this study can provide a simple and quick evaluation of granulate strength in a wet status. Generally, this developed method can prepare granulated Fe-Si binary oxide adsorbents for column adsorption of arsenic from water.