以水质监测促水源保护

介绍了供水公司如何利用水质监测和自身优势条件促进水源保护工作，列举了11条促进水源保护的措施和经验。     

二氧化氯对水中锰离子去除的试验研究

通过氧化/混凝工艺静态模拟试验,考察了二氧化氯对水中锰离子去除的情况及其影响因素。试验表明,二氧化氯投加量、原水pH值、水中锰离子的初始浓度、预氧化时间和混凝剂投加量对除锰都有很大的影响。当原水锰离子质量浓度为5 mg/L时,氧化剂预氧最佳pH值为7~9,二氧化氯最佳投加量分别为10 mg/L,二氧化氯最佳预氧化时间分别为40 min,最佳混凝剂的投加量分别为2mg/L。二氧化氯对锰离子的去除率分别为90.8%     

Effect of Ozone Dosage for Removal of Model Compounds by Ozone/GAC Treatment

This research employed batch ozonation and GAC (granular activated carbon) column to investigate the effect of preozonation dosage on the subsequent GAC adsorption, in terms of the adsorption capabilities for small and large molecules.

For large target compounds like humic acid, the adsorption efficiency was improved with higher ozone dosages, whereas the combined effect of ozonation coupling with GAC for small model compounds seems to be negative. In addition, there is a selective adsorption between the chlorinated disinfection by-product (DBP) precursors and other non-precursors, and most of the non-precursors are less adsorbable than the precursors.     

Improvement in the Effectiveness of Ozonation of Drinking Water Through the Use of Hydrogen Peroxide

Addition of hydrogen peroxide to water during ozonation increases the rate of oxidation of organic compounds and ozone transfer. Coupling ozone with hydrogen peroxide can increase the efficiency of a drinking water treatment line, for example in removing THM precursors. To optimize this oxidation process, the quantity of hydrogen peroxide added and the point of injection must be carefully selected.     

The Combination of Ozone/Hydrogen Peroxide and Ozone/UV Radiation for Reduction of Trihalomethane Formation Potential in Surface Water

Applied ozone dosages of 20, 25, and 30 mg/L to lake water utilized by the city of Shreveport, LA produced no significant reductions in trihalomethane formation potentials (THMFP). However, the addition of 20 mg/L of hydrogen peroxide and/or 0.67 W/L of UV radiation (254 nm) in combination with ozone produced decreases in THMFP of over 60% in 60 minutes. Smaller THMFP decreases were seen with shorter contact times. The use of H₂O₂ and/or UV in combination with O₃ increased the percentage of applied ozone consumed by the lake water (i.e., enhanced the ozone mass transfer) five times over simple ozonation.     

Automation of a Plant Treating Water With Ozone

The particularly powerful means supplied by commercial microcomputers made it possible to build this two–stage ozonation plant designed to ensure the chemical demand in oxidizing agent ofthe water in a first step and the viricidal action of this oxidizing agent ina second step. This plant was designed with one single ozone production unit and for quite variable flows of water tobe treated. Now, because such means are available, it is impossible to separate the design of acomplex ozonation plant from that of its automatic control system in particular since one cannot be looking for an economical and reliable system without conducting an overall analysis of the problem.     

The Determination of Carbonyl Compounds in Ozonated Water by the PFBOA Method

PFBOA, O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine, is excellent as a derivatizing agent in the GC determination of carbonyl compounds in ozonated water samples. Surface and waste waters have been ozonated. The carbonyl ozonation by-products were identified as PFBOA derivatives by gas chromatography-mass spectrometry. The main by-products of ozonation identified were formaldehyde, glyoxal, methylglyoxal, and 13 other compounds. The characteristics of the first three compounds with respect to production and decomposition during ozonation are discussed.     

The Use Of High Concentration Ozone For Water Treatment

The use of high concentration ozone (HCO) in potable water treatment has been examined at laboratory scale with a gaseous concentration of 19% w/w. This has been compared with conventionally generated ozone at 1.5% w/w. The results of the study have shown that greater transfer efficiencies and higher ozone residuals are possible with HCO. In addition, faster rates of atrazine removal and significantly greater reductions in color and trihalomethane formation potential (THMFP) were observed with HCO.     

SPE—GC／MS法测定水中苯胺类化合物条件优化的研究

采用全自动固相萃取装置（SPE）代替传统的液液萃取前处理方式,通过不断优化固相萃取仪器条件,筛选各种类型的固相小柱,调节不同pH值的样品,增加有机改良剂等方式,使样品的加标回收率及重现性等得到了很大提高。使用气相色谱一质谱联用仪（GC／MS）代替气相色谱仪,使被测物质定性更加准确,也排除了一些杂质和仪器假阳性的干扰,为及时准确地分析检测地表水中的苯胺类物质提供了方法依据。     

A New Method for Determining Gas Phase Heat of Formation of Aromatic Energetic Compounds

A new correlation is introduced for desk calculation of gas phase heat of formation of aromatic energetic compounds that contain the elements of carbon, hydrogen, nitrogen and oxygen. Predicted gas phase heats of formation for 26 energetic compounds have a root mean square of deviation from experiment of 20.67 kJ/mol, which is in good agreement with respect to measured values of oxygen‐lean and oxygen‐rich aromatic energetic compounds.     

Removal of Aromatic Nitro Compounds from Water by Ozonation

Experimental studies were carried out on the removal of five species of aromatic nitro hydrocarbons by ozonation. Ultraviolet spectrograms with distinct absorption peaks were plotted for each of them. It has been found that the absorbances of aqueous solutions containing the single compounds mentioned above increase to different extents at the wave lengths ranging from 200 to 230 nanometers with increase of ozone dosages. This is ascribed to the nitrite ions splitting out of the benzene rings and being further oxidized to nitrate ions by ozonation.

It has been indicated that the removal of the five species of aromatic nitro compounds by ozonation can well be expressed mathematically by first order reaction equations. Besides, the reaction constants and half-life periods for various species of the tested nitro compounds were calculated at different temperatures and pH.

An ozonation effect index (OI) was developed in the study to express the degree of degradation of substrates by ozonation, by means of which the five aromatic nitro hydrocarbons were compared with each other and finally ranked in the following order from greatest to smallest degrees of degradation:

p-nitroaniline > nitrobenzene > p-dinitrobenzene > p-nitrotoluene > m-dinitrobenzene

It has also found that the CODm/M ratio increases with ozone doses. This means that some easily degradable intermediates are produced, and increase in concentration with increase of ozone dose in the ozonation process.

The mechanisms of removing the five aromatic nitro hydrocarbons are discussed from the viewpoint of orienting effects of substituent groups on the aromatic rings.     

石墨炉原子吸收光谱法检测尿铅含量

参考WS/T18-1996中尿铅测定方法,优化仪器的操作条件和样品处理方法提高检测的准确性,检测某厂18名职业工人接触的尿铅水平。采用PdCl2作为化学改进剂,无需消解,将尿样稀释后直接进样,方法试剂用量少,操作简便、快速、灵敏度高,对环境污染小,适宜大批样品的检测。     

Optimization of NOM Removal during Water Treatment

Abstract

The aim of this paper is to describe the removal efficiency of individual fractions of natural organic matter (NOM) and the aluminum transformation during treatment of two types of surface water with an increased concentration of NOM of various origins. The coagulation conditions (dose of destabilization reagent and reaction pH value) were optimized for the best NOM and aluminum removal. The results show that the NOM removal efficiency depends on the NOM character, using destabilizing reagents and reaction conditions. The optimized doses of destabilization reagents influence especially the removal of hydrophilic charged (CHA) and very hydrophobic acids (VHA) fractions during treatment of both types of raw water. In contrast to this, the removal of hydrophilic neutral (NEU) fraction is very low (? _NEU =0.13–0.22). The optimal destabilization reagent dosage is characterized by the lowest content of the total reactive aluminum concentration and relatively low concentration of dissolved organic aluminum.     

Ozonation of Humic Substances: Effects on Molecular Weight Distributions of Organic Carbon and Trihalomethane Formation Potential

Four different sources of humic substances were studied to determine the effects of ozonation on molecular weight-distributions, based on dissolved organic carbon (DOC) and trihalomethane formation potential (THMFP). Solutions of two soil-derived fulvic acids and a one soil-derived humic acid, as well as dissolved organic matter (DOM) associated with a natural water source were studied. Both gel permeation chromatography (GPC) and ultrafiltration (UF) were employed to define apparent molecular weight (AMW). Applied ozone doses ranged from 2.0 to 2.5 mg O₃/mg DOC. Overall samples of untreated and ozonated waters, as well as individual molecular weight fractions, were characterized according to DOC, UV absorbance, and THMFP. Ozonation resulted in a significant disappearance of higher AMW material with a corresponding increase in lower AMW material. Although little overall reduction in DOC concentration was observed, significant overall reductions in UV absorbance and THMFP levels were observed.     

基于GA-MLR方法的有机化合物热膨胀系数的QSPR研究

利用QSPR研究方法,结合遗传算法(Genetic Algorithm,GA)和多元线性回归(Multiple Linear Regression,MLR),建立了3635个有机化合物液相膨胀系数的QSPR模型。该模型包含6个描述符,对于训练集R2=0.833%,Q2=0.810%,RMSE和AARD分别是0.043%和1.02%,测试集的统计结果是R2=0.811,RMSE=0.061%,AARD=1.425%。这个模型对于包含大量有机化合物的数据集来说,是可靠并稳定的,具有较好的预测能力。     

Are the Results of Ozonation of Model Compounds at High Concentrations Transferable to the Conditions of Drinking Water Treatment With Ozone?

Organic compounds of the different classes of substances (isobarbituric acid, citraconic acid and o-chlorophenol) were ozonized while varying their initial concentrations (c = 10^-3 to 10^-5 mol/L) at pH 7. In the case of isobarbituric acid at 10-3 mol/L, formyloxaluric acid, oxaluric acid, and formic acid were identified. At an initial concentration of 10^-3 mol/L, alloxanic acid and oxalic acid were formed in addition to oxaluric acid and formic acid. In both cases, the rates of elimination are similar.After ozonation of citraconic acid (c = 10^-5 mol/L, pH 7), the following oxidation products were identified: glyoxylic, acetic, formic, oxalic, pyruvic, and hydroxypyruvic acids.     

一掺多回流程掺水参数优化

大庆油田某区块采用一掺多回的掺水集输流程,但在系统运行过程中,能耗大,运行费用高等问题日益凸显。为降低掺水系统能耗,针对一掺多回掺水集油流程,以掺水量、掺水温度为设计变量,系统运行费用最低为目标函数,压力、温度为约束条件,建立能耗关联模型。利用混合惩罚函数法和改进的共轭方向法对模型求解,得到掺水系统的最佳掺水温度与最佳掺水量。与优化前相比,一掺多回流程掺水系统年掺水量降低27 841 t,掺水温度降低5.5℃,每年可节约能耗费用6.95×105元。     

阴离子表面活性剂处理含铬工业废水

采用传统的铁盐作净水剂，用NaOH调节pH值在7．0左右，生成Fe（OH）3和Cr（OH）3沉淀，加入阴离子表面活性剂，利用沉降达到处理含铬废水的目的。治理结果：沉降速率快，去除率达99％，Cr^6 浓度远低于0.5mg/L。     

Removal of Organic Compounds Containing a Benzene Ring from Water by Adsorptive Micellar Flocculation

The removal of low-molecular-weight benzoic acid (benzoic acid, p-toluic acid, and salicylic acid)-derived and aniline (aniline, 4-chloroaniline, and 2,6-dimethylaniline)-derived organic compounds through adsorptive micellar flocculation (AMF) with anionic surfactants (sodium dodecyl sulfate, SDS) and aluminum sulfate was demonstrated. The interactions between SDS and the organic compounds were studied using ¹H nuclear magnetic resonance (NMR) spectroscopy. Batch AMF experiments were conducted to study the influence of several factors on target pollutant removal. For benzoic acid derivatives, the removal rate was improved by increasing the SDS and Al concentrations, while increases in the concentrations of the organic pollutant tended to decrease the removal rate. The highest removal efficiencies were observed with p-toluic acid (95.4%) > salicylic acid (84.5%) > benzoic acid (76.5%) under weakly acidic conditions due to the greater hydrophobicity of p-toluic acid and the complexation of the Al salts and the salicylic acid. The removal rates of the aniline derivatives were positively related to the SDS concentration and negatively related to the pH. At a pH of 3.0, the highest removal rates of aniline, 4-chloroaniline, and 2,6-dimethylaniline (91.3%, 98.0%, and 97.6%, respectively) were observed. For aniline compounds, charge neutralization between the SDS anions and aniline cations dominated the removal process. These findings provide new insights for the development of further applications of AMF for the removal of benzoic acid and aniline derivatives.     

高藻水的预氯化技术优化探讨

对预氯化过程中的投氯量、反应时间等反应条件的控制以及当原水中藻类数量、酚类物质含量特别高时,预氯化、粉末活性炭的联用等作了论述。认为如果能很好地控制预氯化的反应时间、投氯量,预氯化不会明显增加水厂出水中三致物质的量;预氯化与粉末活性炭联用时,两工艺之间应间隔适当的时间,以减轻氯对粉末活性炭吸附的影响。