饮用水臭氧应用安全性研究

对预臭氧、臭氧—生物活性炭等技术与常规水处理工艺联用中有机物去除效果、消毒副产物THMFP的消除等进行了研究。结果表明:采用适量臭氧(如1mg/L)预氧化,可有效提高混凝过程中有机物去除率;THMFP从常规处理的116μg/L降至78μg/L(1mg/LO3)。与预臭氧强化混凝联用的臭氧—生物活性炭工艺能进一步降低DOC和THMFP。研究发现:溴酸盐随着臭氧含量呈现起伏变化,溴酸盐相关前驱物不易分离去除。两次臭氧投加(预臭氧和主臭氧)均导致溴酸盐、AOC和甲醛升高;其含量可分别在后续的混凝过滤及生物活性炭过程中得到控制,仅AOC含量较原水和常规工艺出水有所升高。     

东太湖水源臭氧-活性炭工艺消毒副产物的生成规律与控制

对以东太湖水为水源的臭氧—活性炭处理工艺和常规处理工艺净水厂的消毒副产物生成情况进行了一年的检测,研究了臭氧—活性炭和常规处理工艺各处理单元对消毒副产物生成势的作用情况。结果表明,臭氧—活性炭和常规处理工艺的出厂水中均含有三卤甲烷、卤乙酸、卤乙腈等消毒副产物;与常规处理工艺相比,臭氧—活性炭处理工艺出水中的消毒副产物种类少、总量低,但三溴甲烷、二溴乙酸的生成量高;臭氧氧化能使消毒副产物生成势提高,砂滤工艺对消毒副产物生成势的去除效果稳定,混凝—沉淀工艺比其他工艺单元对消毒副产物生成势的去除效果好,活性炭工艺在夏季对消毒副产物生成势的处理效果比其他季节好。     

饮用水预臭氧化技术的进展

预臭氧化主要用于脱色除臭、去除藻类和藻毒素、控制氯化消毒副产物、初步去除或转化污染物、助凝等 ,对水质的改善程度取决于原水水质和臭氧化条件 ,预臭氧化同时产生一定的醛类、溴酸盐等有害副产物。综述了原水预臭氧化技术的几个热点问题。     

组合工艺控制有机物及消毒副产物前体物的特性研究

通过XAD-8树脂将水中有机物分成疏水性、亲水性两部分,对传统常规处理工艺(混凝气浮、过滤)和深度处理工艺(臭氧氧化、生物活性炭)出水的DOC,UV254THMFP,HAAFP指标以及疏水、亲水有机物去除率进行了检测分析。结果表明,生物活性炭(BAC)单元工艺能同时去除疏水性和亲水性两种有机物,且两者去除率均为最高。其次去除效果较好的是传统的常规工艺。臭氧工艺具有将天然的疏水性有机物氧化成可生化降解的亲水性小分子有机物的特点,在预臭氧+常规以及O3-BAC组合工艺中,起到了强化去除有机物和消毒副产物前体物的效果。     

活性炭结合超滤及纳滤工艺深度处理饮用水的中试研究

金门岛内水库的富营养化程度严重,藻类所产生的臭味物质、有机碳及消毒副产物的浓度非常高,影响岛内民众健康.研究利用活性炭结合超滤及纳滤工艺,将甲基异莰醇-2、土臭素处理嗅阈值以下,将不可挥发溶解性有机炭(NPDOC)从6.4 mg/L降至0.2 mg/L;三卤甲烷生成势(THMFP)和卤乙酸生成势(HAAFP)可分别从489μg/L和656μg/L去除至38μg/L及17.6 μg/L,去除率分别为92%及97%.中试结果表明,各检测项目均符合台湾地区饮用水标准.由32位金门县自来水厂员工测试3种水的适饮性,其中经活性炭结合超滤及纳滤组合工艺处理后的水样水质为多数测试人员所接受.     

常规工艺中消毒副产物季节变化研究

对某给水厂进行了一个水文年的月度监测,重点分析了各工艺段出水的三卤甲烷和卤乙酸浓度变化。结果表明,对消毒副产物控制起关键作用的工艺是预氯化(混凝)、过滤和消毒。预氯化工艺是一个很大的健康隐患,必须严格控制。在过滤工艺中同时存在消毒副产物的生成和去除两种作用,对三卤甲烷的去除率明显较高,而卤乙酸在过滤前后变化不大。在清水池消毒过程中游离氯会与消毒副产物前体物继续反应生成消毒副产物。     

微絮凝-大梯度磁滤工艺对消毒副产物前驱物控制的研究

以珠江水为原水,利用微絮凝-大梯度磁滤工艺对水中消毒副产物前驱物进行处理,研究工艺的磁场强度和磁滤速度的变化对消毒副产物生成势(THMFP)和UV_(254)的去除效果影响。研究发现,去除THMFP以去除三氯甲烷生成势为主;THMFP的去除效率随着磁场强度的升高或滤速的降低而升高,在磁场强度为0.23T时达到最高为47.83%,磁滤速度为6~8m/h时,去除率稳定在46%左右;UV_(254)的去除效果受滤速的影响较大,滤速从6 m/h提高到16 m/h时,去除率从57.56%下降到39.58%,而磁场强度的变化对UV_(254)的去除效率影响较小,去除率稳定在46.0%~50.7%。     

MIEX(R)树脂联合混凝工艺去除消毒副产物效能研究

以强碱性阴离子吸附树脂——MIEX~?树脂为吸附剂,研究了该树脂联合混凝工艺(下称组合工艺)对原水中有机物及氯代消毒副产物生成势(DBPs FP)的去除效果。吸附动力学试验拟合结果表明,MIEX~?树脂吸附过程更符合Elovich吸附动力学模型,R~2大于0.99;与常规混凝工艺相比,组合工艺可以提高10%～20%的消毒副产物生成势(三卤甲烷生成势THMs FP、三氯乙醛生成势CH FP、可吸附有机卤素生成势AOX FP)去除率。有机物分子质量分级结果表明,组合工艺对MW5 000的有机物去除效果最好,而DBPs前驱物的分子质量主要集中在MW1 000和MW5 000。组合工艺对于控制DBPs FP有较好的效果,对生产具有实际意义。     

给水预臭氧化与预氯化对比试验研究

通过常规给水处理工艺预臭氧化和预氯化对比试验,研究了预臭氧化工艺对水中浊度、氮氮和CODMn的去除效果,对三卤甲烷生成的影响,及其致突变活性的变化。结果表明预臭氧化工艺沉淀池和滤池出水浊度均低于预氯化工艺,其对有机物的去除效果明显优于预氯化工艺,对CODMn的总去除率达53.4%,并能有效去除原水中大量的三卤甲烷前体物,而在致突变活性方面预臭氧化工艺滤后水更安全可靠。同时试验得到在原水CODMn为5-6 mg/L条件下臭氧最佳投加量为1-1.2 mg/L。     

常规工艺对消毒副产物及前体物的去除

以西南某市L水厂为测试对象 ,研究了常规水处理工艺过程对消毒副产物及其前体物的去除特性 ,并且提出了控制饮用水中消毒副产物的几点对策。研究结果表明 :常规水处理对三卤甲烷前体物 (THMsFP)和卤乙酸前体物 (HAAsFP)具有很好的去除效果 ,去除率分别为 50 %以上、4 3%～ 6 4 % ,但对卤乙酸和三卤甲烷却无去除作用 ;预氯化是生成出厂水中THMs、HAAs的主要原因。     

Natural Organic Matter and Disinfection By-products Formation Potential in Water Treatment

The performance of a conventional sequence (pre-ozonation, coagulation/ flocculation/ sedimentation, filtration, disinfection) and two non-conventional sequences (pre-ozonation, nanofiltration; and pre-ozonation, coagulation/ flocculation/ sedimentation, nanofiltration) on the removal of natural organic matter (NOM) and disinfection by-products (DBPs) formation potential was evaluated. Raw and treated waters were characterized in terms of molecular weight, which includes the amount of NOM removed and the qualitative changes in the NOM characteristics (molecular weight and hydrophobicity) since they could be directly related with the DBPs formation. The results demonstrate that, for the type of raw water analysed (hydrophilic with low dissolved organic carbon content, 0.99 L/(mg.m) and 1.31 mg DOC/L), both treatment sequences remove larger molecular weight compounds (>1,900 g/mol). Treated waters have the dominant fractions in the smaller molecular size fractions (<750 g/mol). However, the sequences with nanofiltration have a higher percentage of low molecular weight compounds removed (between 430 and 250 g/mol), when compared with conventional sequence, thus the water from nanofiltration sequences will have lower DBPs formation potential. The removal of the smallest molecular size fractions can be enhanced by optimising the water treatment process and the quality of water will improve relating with DBPs formation.     

臭氧与活性炭深度处理微污染原水试验研究

采用"预臭氧氧化 常规处理 GAC/O3-BAC深度处理"工艺针对南方某市微污染原水进行中试研究.结果表明:预臭氧能明显提高浊度、有机物和THMFP的去除效果,在此条件下常规出水浊度平均值＜O.1 NTU,与无预处理相比,CODMn去除率提高17.52%,氯消毒后CHCl3浓度降低86.4%;O3-BAC工艺对有机物、CHCl3的去除效果和吸附寿命均优于GAC工艺,但生物膜的脱落会影响浊度的去除效果;随着炭床厚度增加,GAC滤池中,CODMn呈线性降低,而BAC滤池中,上部500～1 000 mm厚度内,CODMn快速降低并稳定在一定的水平上.     

Effect of peracetic acid, ultraviolet radiation, nanofiltration-chlorine in the disinfection of a non conventional source of water (Tula Valley).

Water supply for human consumption requires certain quality that reduces health risks to consumers. In this sense, the process of disinfection plays an important role in the elimination of pathogenic microorganisms. Even though chlorination is the most applied process based on its effectiveness and cost, its application is being questioned considering the formation of disinfection by-products (DBPs). Therefore, alternative disinfectants are being evaluated and some treatment processes have been proposed to remove DBPs precursors (organic matter. This paper reports the results of disinfection of a non conventional source of water (aquifer recharged unintentionally with raw wastewater) with peracetic acid (PAA) and ultraviolet radiation (UV) as well as nanofiltration (NF) followed by chlorination to produce safe drinking water. The results showed that a dose of 2 mg/L PAA was needed to eliminate total and faecal coliforms. For UV light, a dose of 12.40 mWs/cm2 reduced total and faecal coliforms below the detection limit. On the other hand, chlorine demand of water before NF was 1.1-1.3 mg/L with a trihalomethane formation potential (THMFP) of 118.62 microg/L, in contrast with chlorination after NF where the demand was 0.5 mg/L and THMFP of 17.64 microg/L. The recommended scheme is nanofiltration + chlorination.     

石灰法处理甲醛废水的试验研究

采用石灰法处理甲醛废水,取得了良好的效果。结果表明:石灰法能有效降低甲醛废水中的甲醛浓度。在合适的反应条件下,降解甲醛浓度为2001.5mg/L、CODCr为3019mg/L的甲醛废水,反应90min后,能使甲醛和CODCr的去除率分别达99.93%和5.58%。石灰投加量、反应温度、水样pH、水样起始甲醛浓度对最终处理效果都有一定程度的影响。     

微砂增效结团絮凝技术处理低浊高藻水的中试研究

针对西安市汤峪水库夏季水质特点和处理要求,提出并采用微砂增效结团絮凝工艺对该原水处理进行中试研究.微砂增效结团絮凝技术是将微砂增效与结团絮凝有机组合的新型水处理工艺.试验结果表明,利用微砂增效结团絮凝技术处理汤峪水库低浊高藻水是切实可行的,系统具有运行稳定性高、出水水质好等特点,且处理效率明显高于采用回流污泥的增效澄清技术.微砂增效结团絮凝工艺能够有效降低出水浊度和CODMn;当微砂投量0.5 g/L时的过程控制参数为PAC投量15mg/L,PAM投量0.4 mg/L,机械搅拌转速8 r/min,上升流速达35 m/h时,藻类去除率可达80％,CODMn去除率达40％,浊度可控制在1.5 NTU以下.     

Correlations between surrogate nitrogenous organic precursors and C-, N-DBP formation

Nitrosamines have been emerging as disinfection byproducts in drinking water using source water impacted with domestic wastewaters. Nitrogenous organic compounds are suggested as precursors of nitrosamines, but many of them have not been identified. This study investigated the correlations between nine selected nitrogenous organic compounds with different characteristics and corresponding disinfection by-product formation potentials (nitrosamines, trihalomethanes (THMs), and haloacetic acids (HAAs)) from their reactions with free chlorine, chlorine dioxide and monochloramine. Besides dimethylamine, the well-known precursor of nitrosamines, 3-(N,N-dimethyloctylammonio)propanesulfonate (3-N,N-DAPSIS) inner salt and benzyldimethyltetradecylamine (benzalkonium chloride, BKC) were suggested as important nitrosamine precursors. 3-N,N-DAPSIS could form about 1,000 ng/L of N-nitrosodimethylamine (NDMA) and more than 1,000 μg/L of THMs. More than 150,000 ng/L of NDMA were observed when BKC was treated with monochloramine, and high levels of THMs (up to 2,700 μg/L) were also yielded. As expected, free chlorine produced higher levels of THMs and HAAs, and chlorine dioxide generated minor levels of traditional DBPs. Nitrosamines were mainly formed when the precursors were treated with monochloramine.     

Effect of ozone on disinfection by-product formation of algae

The presence of algae in a drinking water source can have a significant impact on the treatment of that water. Algae and their extracellular organic matter can be precursors for disinfection by-product (DBP) formation which is of concern for treatment plants that employ pre-chlorination. This research examined the DBP formation of suspensions of Scenedesmus quadricauda a green alga, and the effect of ozonation on that formation. Trihalomethane formation potential (THMFP) was found to increase by 10% to 3090 when preozonation was applied versus non-ozonated samples. A slight increase in haloacedc acid (HAA) formation was also observed in the ozonated samples. Ozonation caused an increase in the dissolved organic carbon content of the algal suspension, thereby increasing the concentration of precursors. The alkalinity of the water did not significantly affect the formation potential of either THMs or HAAs.