污水厂二级处理出水的臭氧氧化特性及其动力学

研究了城市污水厂二级处理出水的臭氧氧化特性及其动力学规律。结果表明，臭氧氧化可以显著提高二级处理出水的可生化性，当臭氧投量为10mg／L、接触时间为2min时，可使其BDOC和TOC／UV254值分别提高约1倍；当接触时间为4min时，臭氧氧化对COD、TOC的去除率分别达到25．7％和16．5％，使UV254和色度分别降低了62．31％和79．25％，同时分子质量〈1ku的有机物所占比例由原来的52．9％升高到72．6％。当接触时间从2min延长到30min时，对NH3-N的去除率由1．3％增加到22．5％。拟合结果表明，在（0～1．6）、（1．6～16）和（16～30）min的时段内，臭氧氧化反应均为一级反应，但反应速率逐渐降低。     

臭氧-生物活性炭与单独活性炭工艺处理效果比较

为有效去除水中有机物,明确是否应在活性炭前投加臭氧,比较了臭氧-生物活性炭（O3-BAC）和单独活性炭（GAC）过滤对CODMn、UV254和TOC的去除效果以及两套系统对提高水质生物稳定性的作用.研究发现,O3-BAC对CODMn、UV254和TOC的平均去除率比GAC分别高10.3%、11.1%、7.1%,对AOC的去除率＞80%,出水AOC浓度为25.9～46.4μg乙酸碳/L,属生物稳定性水质;单独GAC柱对AOC的去除率在40%左右,出水AOC浓度为85.8～117.6μg乙酸碳/L,有时不能满足水质生物稳定性的要求.可见在活性炭前投加臭氧,可以强化活性炭对有机物的去除作用,延长活性炭的使用周期,增强活性炭滤池的生物降解能力.     

臭氧-生物活性炭工艺深度处理石化废水

研究了臭氧——生物活性炭(O3-BAC)工艺在石化废水深度处理中的效能，为应用提供一定的理论依据。试验结果表明，当O3的投加量为6mg/L、接触时间为30min、炭柱停留时间为30min时，O3-BAC工艺对比COD、油类、色度的去除率分别为69％、86％、88％，同时O3和BAC协同作用使O3-BAC的活性炭柱出水水质稳定，延长了活性炭的使用寿命。试验证明，O3-BAC工艺在石化废水深度处理中的应用是可行的。     

预臭氧化工艺处理高藻水的应用研究

以滦河水为处理对象,对天津市泰达自来水厂预臭氧化—紫外/氯联合消毒工艺的运行效果进行分析.分别对各处理单元出水中的藻类、叶绿素a、pH值、浊度、DOC和UV254进行测定,结果表明:整个工艺运行平稳,出水水质较好.原水经过预臭氧化处理后,藻类数量和叶绿素a浓度均有降低,预臭氧化单元对藻类和叶绿素a的平均去除率分别为38.26％和36.25％;整个工艺对藻类和叶绿素a的平均去除率分别可达75.55％和99.01％.此外,预臭氧化对原水的pH值及去除浊度、UV254和DOC也有一定的影响.预臭氧化可有效降低浊度和UV254值,但对去除DOC的影响不明显.     

Ru/Al2O3催化臭氧氧化降解邻苯二甲酸二甲酯活性研究

系统地考察了Ru/Al2O3催化剂对邻苯二甲酸二甲酯(DMP)溶液臭氧氧化过程的影响.结果表明Ru/Al2O3可以显著提高臭氧氧化的效果,反应120 min后对TOC的去除率可以由单独臭氧氧化的23.9%提高到71.6%.在试验考察的范围内,Ru的最佳负载量为0.1%;BET和XRD分析表明焙烧温度在600℃、催化剂粒径为0.5～1.0 mm时催化剂载体主要以γ-Al2O3形式存在,得到的催化剂具有较大的表面积、较多的表面活性位点,此时催化臭氧氧化的活性最高.通过单独臭氧氧化,单独臭氧氧化后再进行催化剂吸附,催化臭氧氧化的对比试验证明了Al2O3催化剂对体系TOC的去除主要是基于催化作用.     

两级生物处理组合工艺对有机物的去除效果

针对高氨氮、高有机物污染的原水水质特征,徐泾水厂示范工程采用了两级生物处理组合工艺.对该工艺去除有机物的效果进行了深入研究,结果显示:组合工艺处理高有机物污染原水的效果良好,对CODMn、DOC和UV254的去除率分别达到60.4％、54.2％和52.1％,出厂水的CODMn浓度基本达标.组合工艺对有机物的去除特性表现为:①生物预处理和BAC单元对0.5 ～1ku区间的小分子有机物的去除效果最好,前者对该区间DOC和UV254的去除率分别为61.9％和80.8％,后者的分别为43.7％和45.5％;②强化混凝沉淀单元对大分子质量有机物的去除效果显著,对＞30、(10 ～30)、(3～10)和(1～3) ku区间DOC的去除率依次为29.6％、42.4％、31.7％和81.5％,对相应区间UV254的去除率依次为22.1％、80.1％、54.8％和71.7％;③砂滤单元以去除大分子质量有机物为主,对＞30、(10 ～30)和(3～10) ku区间DOC的去除率分别为62.8％、81.8％和69.8％,对相应区间UV254的去除率分别为50.6％、69.7％和66.1％.与对DOC的去除特性不同,砂滤单元对小分子质量的UV254也有较好的去除效果,对0.5～1 ku和＜0.5 ku区间UV254的去除率分别为41.3％和26.6％.     

ZnO/O3工艺降解水中微量有机物的研究

以实验室制备的粉末氧化锌(ZnO)为催化剂,考察了ZnO/O3工艺去除水中有机物的效能.采用总有机碳(TOC)指标反映水中有机污染物的含量.结果表明:臭氧投量为1 mg/L、ZnO投量为300 mg/L时,反应60 min后ZnO-O3工艺对TOC的去除率为46%,比单独臭氧化提高了1倍;反应温度明显影响该工艺对有机物的降解效果,在水温为5,10,20和25 ℃时,TOC的去除率分别为17.5%,31.5%,45.9%和51.3%.臭氧浓度和催化剂投量的增加,可以提高TOC的氧化降解效率.     

O3/BAC工艺深度处理某工业园区废水的效果

开展了规模为36 m3/d的中试研究,考察了不同臭氧投加量下臭氧/生物活性炭(O3/BAC)工艺深度处理某印染制革工业园区污水厂生化处理出水的效果,探讨了作用机理.当臭氧投量为25 mg/L时对COD、色度、TOC、UV254的去除效果最佳,去除率分别为17.4％、54.3％、14.7％和47.5％.在生物活性炭挂膜启动期间,系统对COD的去除率先下降后上升,32 d后稳定在50％左右.在生物活性炭稳定运行期间,系统进水COD和色度平均值分别为100 mg/L和112.5倍,出水值则分别降至50 mg/L和5倍,达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)中的一级B标准.臭氧将大分子的有机物降解成小分子有机物后被生物活性炭吸附和氧化,同时产生部分微生物胞外分泌物及其代谢产物,TOC和UV254在分子质量＜1 ku区间的比例分别由进水的60.7％和58.8％增加至出水的66.8％和65.7％.     

亚硝酸盐氮对臭氧氧化有机物的影响研究

在臭氧氧化处理微污染原水的工艺中，臭氧对有机物的去除效果与水中还原性无机物的含量有关。通过试验考察了水中NO2^--N对臭氧氧化有机物的影响。结果表明，水中较高浓度的NO2^--N可消耗臭氧投加量的40％左右，并降低了臭氧对THMs前体物的去除率，也影响其提高水中可生物降解有机物浓度的能力；碱度的增加可增强NO2^--N对臭氧的竞争利用，降低臭氧对TOC和UV254的去除率。     

O3/BAC工艺应用于城市污水深度处理

为使再生水适合不同用途,对经过混凝沉淀和砂滤处理的再生水进行了臭氧-生物活性炭的深度处理.在臭氧消耗量和反应时间分别为5 mg/L和10 min,BAC空床停留时间(EBCT)为10 min的条件下,臭氧-生物活性炭工艺对CODMn、DOC、UV254和色度平均去除率为32.4%、29.2%、48.6%和80.1%,出水CODMn、DOC、UV254和色度的平均值分别为3.3 mg/L、4.0mg/L、0.05 cm-1和2.0倍;臭氧生物活性炭工艺出水SDI《4,从而满足了反渗透系统的进水要求.     

高级氧化技术对垃圾渗滤液的处理研究

介绍了高级氧化技术中的臭氧氧化法、Fenton法、湿式催化氧化法、超声波氧化法以及组合工艺处理垃圾渗滤液的研究进展,阐述了这些高级氧化技术的反应机理以及特点,并对高级氧化技术处理垃圾渗滤液研究方向进行了分析,对垃圾渗滤液的有效处理具有积极指导意义。     

Electrochemical sulfide oxidation from domestic wastewater using mixed metal-coated titanium electrodes

Hydrogen sulfide generation is a major issue in sewer management. A novel method based on electrochemical sulfide oxidation was recently shown to be highly effective for sulfide removal from synthetic and real sewage. Here, we compare the performance of five different mixed metal oxide (MMO) coated titanium electrode materials for the electrochemical removal of sulfide from domestic wastewater. All electrode materials performed similarly in terms of sulfide removal, removing 78 ± 5%, 77 ± 1%, 85 ± 4%, 84 ± 1%, and 83 ± 2% at a current density of 10 mA/cm² using Ta/Ir, Ru/Ir, Pt/Ir, SnO₂ and PbO₂, respectively. Elevated chloride concentrations, often observed in coastal areas, did not entail any significant difference in performance. Independent of the electrode material used, sulfide oxidation by in situ generated oxygen was the predominant reaction mechanism. Passivation of the electrode surface by deposition of elemental sulfur did not occur. However, scaling was observed in the cathode compartment. This study shows that all the MMO coated titanium electrode materials studied are suitable anodic materials for sulfide removal from wastewater. Ta/Ir and Pt/Ir coated titanium electrodes seem the most suitable electrodes since they possess the lowest overpotential for oxygen evolution, are stable at low chloride concentration and are already used in full scale applications.     

饮用水的臭氧氧化技术

通过介绍臭氧在饮用水处理中的应用，分析了臭氧处理系统的功能及其与污染物的反应机理。臭氧氧化技术与其他处理方法的联用在给水深度净化领域有十分广阔的应用前景。     

Wet peroxide oxidation of chlorophenols

This study evaluates the application of Wet Peroxide Oxidation (WPO) for the treatment of solutions containing 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP). These compounds are of special interest due to their high toxicity and low biodegradability. WPO is included in the Advanced Oxidation Processes, which are technologies based on an initial formation of hydroxyl radicals that further oxidize the organic matter. The influence of some operating conditions such as temperature, dosage of hydrogen peroxide and initial concentration of the chlorophenols was studied in absence of a catalyst. The results of this study prove that 4-CP and 2,4-DCP can be completely removed from wastewaters by means of WPO. Total Organic Carbon (TOC) and 4-CP removals of 72.3% and 100%, respectively, were achieved working at 100 degrees C with 2.5 mL of H(2)O(2) and an initial concentration of 500 ppm of 4-CP after 90 min of reaction. Under the same conditions but with an initial concentration of 500 ppm of 2,4-DCP a TOC removal of 59% and a complete removal of the target compound were achieved.     

Online titrimetric and off-gas analysis for examining nitrification processes in wastewater treatment

The two steps of nitrification, namely the oxidation of ammonia to nitrite and nitrite to nitrate, often need to be considered separately in process studies. For a detailed examination, it is desirable to monitor the two-step sequence using online measurements. In this paper, the use of online titrimetric and off-gas analysis (TOGA) methods for the examination of the process is presented. Using the known reaction stoichiometry, combination of the measured signals (rates of hydrogen ion production, oxygen uptake and carbon dioxide transfer) allows the determination of the three key process rates, namely the ammonia consumption rate, the nitrite accumulation rate and the nitrate production rate.Individual reaction rates determined with the TOGA sensor under a number of operation conditions are presented. The rates calculated directly from the measured signals are compared with those obtained from offline liquid sample analysis. Statistical analysis confirms that the results from the two approaches match well. This result could not have been guaranteed using alternative online methods.As a case study, the influences of pH and dissolved oxygen (DO) on nitrite accumulation are tested using the proposed method. It is shown that nitrite accumulation decreased with increasing DO and pH. Possible reasons for these observations are discussed.     

全流程生物氧化法处理微污染原水研究

许多水厂已经或正在准备采用生物接触氧化预处理（BCO）技术来提高水质，由于对生化处理缺乏深入了解及受传统预加氯处理的限制，现在已经运行的生化处理工艺并不能有效地去除有机污染物。在对预加氯与否所测得试验数据进行分析的基础上，提出了全流程生物氧化（EPBO）的处理工艺。     

氧化剂协同即时成膜型光催化反应器降解有机物

研究了“表观”即时成膜型UV／TiO2光催化反应器降解水中有机污染物的过程中,外加氧化剂与UV／TiO2体系之间的协同效应。在UV／TiO2体系中单独投加H2O2或O3可以提高光催化氧化有机污染物的速率和效率,同时投加H2O2和O3时则光催化氧化的协同作用更加显著,可大大缩短反应时间。不同反应体系的表观速率常数排序为：UV／H2O2／O3／TiO2〉UV／O3／TiO2〉UV／H2O2／TiO2〉UV／O3〉UV／H2O2〉UV／TiO2。     

Electrochemical treatment of spent solution after EDTA-based soil washing

The use of EDTA in soil washing technologies to remediate soils contaminated with toxic metals is prohibitive because of the large volumes of waste washing solution generated, which must be treated before disposal. Degradation of EDTA in the waste solution and the removal of Pb, Zn and Cd were investigated using electrochemical advanced oxidation processes (EAOP) with a boron-doped diamond anode (BDDA), graphite and iron anodes and a stainless-steel cathode. In addition to EAOP, the efficiency of electro-Fenton reactions, induced by the addition of H₂O₂ and the regulation of electrochemical systems to pH 3, was also investigated. Soil extraction with 15 mmol kg⁻¹ of soil EDTA yielded waste washing solution with 566 ± 1, 152 ± 1 and 5.5 ± 0.1 mg L⁻¹ of Pb, Zn and Cd, respectively. Treatments of the waste solution in pH unregulated electrochemical systems with a BDDA and graphite anode (current density 67 mA cm⁻²) were the most efficient and removed up to 98 ± 1, 96 ± 1, 99 ± 1% of Pb, Zn and Cd, respectively, by electrodeposition on the cathode and oxidatively degraded up to 99 ± 1% of chelant. In the electrochemical system with an Fe anode operated at pH 3, the chelant remained preserved in the treated solution, while metals were removed by electrodeposition. This separation opens up the possibility of a new EDTA recycling method from waste soil washing solution.     

Advanced oxidation processes for the degradation of microplastics from the environment: A review

Microplastic pollution has rapidly become one of the major global environmental concerns because of its low biodegradability rate and threat to biota. Although many treatment methods are reported, the advanced oxidation process (AOP) is recommended because of its capacity to completely mineralize organic pollutants into carbon dioxide and water. This review gathers published investigations on recent AOP techniques (UV/solar photolysis and photocatalysis (PC), UV/H₂O₂, Fenton reaction, sonolysis, heat-activated persulphate and peroxymonosulphate) tested for the degradation of microplastics from water and wastewater. The review lists 54 studies, by far the most comprehensive collection on the AOP-driven treatment of microplastics, and is also the first to explain the methods related to the ultrasonic degradation of microplastics. We found that all the reviewed AOP techniques achieved satisfying performance in the degradation of microplastics. This paper proposes recommendations for future research based on the review.     

Catalytic wet oxidation of phenol in a trickle bed reactor over a Pt/TiO2 catalyst

Catalytic wet oxidation of phenol was studied in a batch and a trickle bed reactor using 4.45% Pt/TiO2 catalyst in the temperature range 150-205 degrees C. Kinetic data were obtained from batch reactor studies and used to model the reaction kinetics for phenol disappearance and for total organic carbon disappearance. Trickle bed experiments were then performed to generate data from a heterogeneous flow reactor. Catalyst deactivation was observed in the trickle bed reactor, although the exact cause was not determined. Deactivation was observed to linearly increase with the cumulative amount of phenol that had passed over the catalyst bed. Trickle bed reactor modeling was performed using a three-phase heterogeneous model. Model parameters were determined from literature correlations, batch derived kinetic data, and trickle bed derived catalyst deactivation data. The model equations were solved using orthogonal collocations on finite elements. Trickle bed performance was successfully predicted using the batch derived kinetic model and the three-phase reactor model. Thus, using the kinetics determined from limited data in the batch mode, it is possible to predict continuous flow multiphase reactor performance.