强化混凝去除水源水中三卤甲烷前体物的研究

通过小试试验，研究了通过调整混凝剂聚氯化铝的投加量进行强化混凝，对两种不同水质的水源水中TOC、UV254及三卤甲烷前体物。结果表明，强化混凝能有效提高对TOC、UV254及三卤甲烷前体物去除效果，对TOC的去除率分别达到52.11%和41.25%，对UV254的去除率分别达到29.23%和63.33%，对三卤甲烷前体物的去除率分别达到50.62%和44.75%。     

活性无烟煤滤料控制三卤甲烷生成的生产性试验研究

将自来水厂滤池石英砂滤料更换为活性无烟煤,对比了石英砂、活性无烟煤滤料过滤对水中有机物的去除效果,以及这两种滤料控制三卤甲烷生成的效果。结果表明,将石英砂滤料更换为活性无烟煤滤料,可将CODMn平均去除率由18%提高至46%,UV254平均去除率由6%提高至58%,从而降低THMs前体物含量,使得THMFP的平均去除率由9%提高至42%。     

臭氧活性炭工艺对三卤甲烷前体物的去除性能研究

通过两组试验对水厂臭氧活性炭深度处理工艺去除三卤甲烷前体物的性能进行了研究。结果表明:…臭氧活性炭工艺能有效去除TOC和UV254;对三卤甲烷前体物去除效果显著,去除率达40%以上;臭氧氧化对三卤甲烷前体物去除能力较小,活性炭滤池过滤去除效果显著。经臭氧活性炭工艺处理的水加氯消毒后三氯甲烷生成量较处理前可减少50%以上。臭氧活性炭工艺能有效降低消毒生成三卤甲烷的风险。     

不同的常规与深度处理水厂工艺对水质保障的应用研究

对比常规处理与臭氧-生物活性炭深度处理水厂的运行效果,通过生产试验研究两种工艺对有机物及消毒副产物的控制情况,试验结果表明:深度处理C水厂混凝沉淀效果较好,砂滤后出水浊度达到0.20NTU,混凝沉淀对浊度的去除率达到78.9%,炭滤池对浊度的去除效果有限。混凝沉淀对UV254的去除效果有限,去除率为11.7%~23.8%,砂滤池的去除率为19.0%~25.0%,深度处理C水厂生物活性炭滤池对UV254的去除效果较明显。混凝沉淀对溶解性的氨氮和亚硝态氮均无明显去除效果,经过砂滤后氨氮和亚硝态氮基本得到去除。混凝沉淀对CODMn的去除率约为14.1%,对TOC的去除率约为26.5%,石英砂过滤对CODMn的去除率约为31.0%,对TOC的去除率约为11.4%。常规加碱B水厂的去除效果优于常规A水厂,深度处理C水厂炭滤过程对CODMn的去除率约为43.9%,对TOC的去除率约为32.6%。加碱比不加碱的砂滤池对生成三卤甲烷的风险大大减低,经过臭氧-生物活性炭处理后可以进一步减低出厂水中消毒副产物浓度。     

纯氧曝气-活性无烟煤滤池的生物活性研究

以南方某自来水厂待滤水为对象,通过比较纯氧曝气-活性无烟煤滤池与石英砂滤池的出水水质及滤料的生物活性,研究不同滤料的生物活性对滤池去除效果的影响。试验结果表明,纯氧曝气-活性无烟煤滤池长期运行后,其滤料的物理吸附容量已基本饱和,对污染物的去除主要依赖于生物膜的降解和粘附絮凝作用。在8m/h左右的滤速下,纯氧曝气-活性无烟煤滤池对有机物及氨氮都有较高的去除效果,并能有效控制后续消毒工艺中三卤甲烷的生成,其中,TOC的去除率为28.7%,COD_(Mn)的去除率为33.9%,低浓度氨氮能够彻底去除,并且能够将三卤甲烷的生成量降低20.8%,显著提高水厂的出水水质。     

不同滤料去除、控制三卤甲烷效果的生产性试验研究

在水厂生产性试验的规模,对比研究了不同原水水质条件下,石英砂、活性炭、活性无烟煤这三种不同滤料过滤对TOC、UV254的去除率,以及控制三卤甲烷生成的效果。结果表明,活性炭、活性无烟煤过滤能在混凝-沉淀的基础上进一步降低TOC、UV254,并减小三卤甲烷生成潜能,而石英砂过滤对TOC、UV254基本无去除,对控制THMFP无明显效果。     

不同滤料过滤控制三氯乙醛生成的生产性试验研究

将自来水厂快滤池石英砂滤料更换为活性炭与活性无烟煤,对比这三种滤料过滤对水中有机物的去除效果,以及控制三氯乙醛生成的效果。生产性试验结果表明,活性炭、活性无烟煤过滤对有机物的去除效果明显好于石英砂滤池,TOC、CODMn、UV254去除率均为石英砂滤池的一倍以上。活性炭与活性无烟煤滤池出水的加氯消毒副产物三氯乙醛生成量均远小于石英砂滤池出水。三种滤料过滤后的出水浊度无明显差别,均在0.3NTU以下。     

预臭氧/生物滤池去除消毒副产物的前体物研究

采用预臭氧氧化技术与陶粒生物滤池组合工艺去除原水中消毒副产物的前体物，考察了三卤甲烷前体物和卤乙酸前体物的转化规律。试验结果表明：预臭氧氧化和生物过滤组合工艺对受污染黄河水中三卤甲烷前体物的去除效果不佳，可能会引起出水中前体物浓度的升高；该组合工艺对二氯乙酸前体物有一定的去除作用，对三氯乙酸前体物的去除效果显著。     

炭砂滤池与砂滤池在水厂实际运行过程中的比较研究

在水厂实际运行过程中,通过对炭砂滤池与砂滤池长期运行过程中的处理效果进行比较,研究两种滤池对浊度、CODMn、NH3-H、UV254、TOC、三卤甲烷类消毒副产物的去除效果。结果表明:运行期间炭砂滤池出水平均浊度达到0.17NTU,而砂滤池出水平均浊度为0.22NTU;在前2个月炭砂滤池对CODMn的去除率平均可达60%,随后去除效果有所下降,并稳定在50%左右,砂滤池的去除率稳定维持在20%左右;运行初期炭砂滤池对氨氮的去除效果与砂滤池差别不大,当待滤水的氨氮浓度高达1.57mg/L时,炭砂滤池出水氨氮浓度降至0.36mg/L,而砂滤池出水只能降至0.97mg/L;运行期间炭砂滤池对UV254的去除率先高后低,而砂滤池对UV254的去除率基本稳定在10%以下;当待滤水TOC均值为2.18mg/L,炭砂滤池对TOC平均去除率达到42.28%,而砂滤池对TOC平均去除率仅为16.81%;炭砂滤池过滤后出水中三卤甲烷平均去除率达到34.25%,而砂滤池的平均去除率仅有16.62%。     

生物活性炭与臭氧/活性炭工艺控制DBPs前体物比较

通过比较生物活性炭工艺和臭氧/活性炭工艺去除消毒副产物前体物的性能,分析了经两种工艺处理后生成消毒副产物的风险。结果表明:生物活性炭工艺和臭氧/活性炭工艺对TOC和UV254均有去除效果,但臭氧/活性炭工艺远优于生物活性炭工艺。生物活性炭工艺对三卤甲烷前体物的去除率可达25%以上,而臭氧/活性炭工艺的去除效果更为显著,去除率在40%以上,且以活性炭滤池去除为主。经加氯消毒后,臭氧/活性炭工艺出水三氯甲烷和三氯乙醛的生成量比生物活性炭工艺都有所降低。因此,臭氧/活性炭工艺相比于生物活性炭工艺更能有效降低生成消毒副产物的风险。     

Fate of N-nitrosodimethylamine, trihalomethane and haloacetic acid precursors in tertiary treatment including biofiltration

The presence of disinfection by-products (DBPs) such as trihalomethanes (THMs), haloacetic acids (HAAs) and N-nitrosamines in water is of great concern due to their adverse effects on human health. In this work, the removal of N-nitrosodimethylamine (NDMA), total THM and five HAA precursors from secondary effluent by biological activated carbon (BAC) is investigated at full and pilot scale. In the pilot plant two filter media, sand and granular activated carbon, are tested. In addition, we evaluate the influence of ozonation prior to BAC filtration on its performance. Among the bulk of NDMA precursors, the fate of four pharmaceuticals containing a dimethylamino moiety in the chemical structure are individually investigated. Both NDMA formation potential and each of the studied pharmaceuticals are dramatically reduced by the BAC even in the absence of main ozonation prior to the filtration. The low removal of NDMA precursors at the sand filtration in comparison to the removal of NDMA precursors at the BAC suggests that adsorption may play an important role on the removal of NDMA precursors by BAC. Contrary, the precursors for THM and HAA formation are reduced in both sand filtration and BAC indicating that the precursors for the formation of these DBPs are to some extent biodegradable.     

强化混凝-沉淀-砂滤工艺去除海水中藻类的试验研究

通过考察强化混凝中混凝剂种类及投加量、氧化性助凝剂种类及投加量、氧化时间、pH以及水力条件等因素对海水中Chl-a、CODMn去除效果的影响,确定了试验参数,并后续加入砂滤工艺考察其除藻效果.结果表明:在调节海水pH值为5～6,选用3 mg/L高锰酸钾预氧化30min后,投加混凝剂聚合氯化铝铁(PAFC)对Chl-a和CODMn均有较佳的去除效果.强化混凝-沉淀-砂滤工艺对Chl-a平均去除率可以达到80%以上,对CODMn去除率在50%左右,对浊度的去除率大干97%.     

不同净水工艺对含溴水体消毒副产物生成势的影响

以溴离子和有机物浓度不同的5个水厂原水和各工艺段出水为研究对象,考察了不同净水工艺对三卤甲烷(THMs)和卤乙酸(HAAs)这两类典型消毒副产物生成势和种类分布的影响。结果表明,仅采用常规处理工艺对THMs和HAAs生成势的控制效果不明显,而增设生物预处理和臭氧氧化预处理工艺能显著提高常规工艺对THMs和HAAs前体物的去除效果,臭氧/生物活性炭(O3/BAC)深度处理工艺能进一步去除THMs和HAAs的前体物。增设预处理和O3/BAC深度处理工艺,并采取砂滤池后置的净水工艺流程对THMs和HAAs生成势的控制效果最好。对于含溴水体,溴离子浓度越高,有机物中亲水性组分所占比例越高,经氯消毒后生成的溴代THMs和HAAs所占比例就越高。随着处理工艺流程的进行,THMs和HAAs的生成势逐渐降低,但是它们的溴结合因子逐渐增大,即毒性更大的溴代组分所占比例逐渐增大。     

DBPs removal in GAC filter-adsorber

A rapid sand filter and granular activated carbon filter-adsorber (GAC FA) were compared in terms of dissolved organic carbon (DOC) and disinfection by-products (DBPs) removal. A water treatment plant (WTP) that had a high ammonia concentration and DOC in raw water, which, in turn, led to a high concentration of DBPs because of a high dose of pre-chlorination, was investigated. To remove DBPs and DOC simultaneously, a conventional rapid sand filter had been retrofitted to a GAC FA at the Buyeo WTP in Korea. The overall removal efficiency of DBPs and DOC was higher in the GAC FA than in the sand filter, as expected. Breakthrough of trihalomethanes (THMs) was noticed after 3 months of GAC FA operation, and then removal of THMs was minimal (<10%). On the other hand, the removal efficiency of five haloacetic acids (HAA(5)) in the GAC FA was better than that of THMs, though adsorption of HAA(5) decreased rapidly after 3.5 months of GAC FA operation. And then, gradual improvement (>90%) in HAA(5) removal efficiency was again observed, which could be attributed to biodegradation. At the early stage of GAC FA operation, HAA(5) removal was largely due to physical adsorption, but later on biodegradation appeared to prevail. Biodegradation of HAA(5) was significantly influenced by water temperature. Similar turbidity removal was noticed in both filters, while better manganese removal was confirmed in the sand filter rather than in the GAC FA.     

强化常规工艺处理黄河原水的试验研究

天津在冬季、经长距离调用的黄河原水水质具有低温、低浊、微污染的特点，采用常规工艺处理时出水CODMn很难满足《城市供水水质标准》（CJ／T206-2005）的要求，为此开展了强化常规工艺的试验研究。结果表明，通过采取臭氧预氧化或高锰酸盐复合药剂（PPC）预氧化、高效絮凝刺HPAC强化混凝气浮、改性滤料强化过滤等措施，可显著改善常规工艺的出水水质，对有机物的去除率提高了10％以上，出水CODMn〈3mg／L。臭氧（或PPC）预氧化、HPAC混凝气浮、改性滤料过滤是改善常规工艺出水水质的有效手段。     

复合污染地下水的两级处理工艺中试研究

开展了石英砂+生物活性炭的两级处理工艺净化复合污染地下水的中试研究。结果表明,当石英砂滤料未成熟时,单级过滤对铁、锰的去除效果较好,但是对氨氮及CODMn的去除效果不理想;二级过滤工艺可以明显提高水中氨氮和CODMn的去除效果;滤料成熟后系统对铁、锰、氨氮及CODMn的平均去除率分别达到99.5%,99.9%,93.7%和34.5%。该处理工艺出水水质较好,抗水质冲击负荷能力强,且运行稳定性高。     

二次微絮凝强化过滤效果研究

为提高过滤效果,开展了二次微絮凝强化过滤实验研究,结果表明,采用阳离子聚丙烯酰胺作为微絮凝剂,可以明显改善过滤效果,PAM投量为0.01 mg/L,微絮凝时间为2 min条件下,出水浊度,CODMn,UV254的去除率增加了6.6%,5.6%和6.2%。滤池的水头损失增长规律与常规过滤工艺基本相同。初滤水浊度明显降低,相比于未进行二次微絮凝的滤池而言成熟期可以缩短为30 min～40 min左右。     

改性石英砂滤料强化过滤处理含藻水

采用改性石英硝滤料强化过滤处理含藻水的试验结果表明，与石英硝滤料相比，改性石英硝滤料对含藻水具有优良的处理效果；经混凝沉演后水中的余铝对藻类的去除有促进作用。     

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。     

Occurrence and control of nitrogenous disinfection by-products in drinking water--a review

The presence of nitrogenous disinfection by-products (N-DBPs), including nitrosamines, cyanogen halides, haloacetonitriles, haloacetamides and halonitromethanes, in drinking water is of concern due to their high genotoxicity and cytotoxicity compared with regulated DBPs. Occurrence of N-DBPs is likely to increase if water sources become impacted by wastewater and algae. Moreover, a shift from chlorination to chloramination, an option for water providers wanting to reduce regulated DBPs such as trihalomethanes (THMs) and haloacetic acids (HAAs), can also increase certain N-DBPs. This paper provides a critical review of the occurrence and control of N-DBPs. Data collated from surveys undertaken in the United States and Scotland were used to calculate that the sum of analysed halonitromethanes represented 3-4% of the mass of THMs on a median basis; with Pearson product moment correlation coefficients of 0.78 and 0.83 between formation of dihaloacetonitriles and that of THMs and HAAs respectively. The impact of water treatment processes on N-DBP formation is complex and variable. While coagulation and filtration are of moderate efficacy for the removal of N-DBP precursors, such as amino acids and amines, biofiltration, if used prior to disinfection, is particularly successful at removing cyanogen halide precursors. Oxidation before final disinfection can increase halonitromethane formation and decrease N-nitrosodimethylamine, and chloramination is likely to increase cyanogen halides and NDMA relative to chlorination.