臭氧组合工艺在水处理中的应用

在废水生化处理前进行臭氧预氧化,可以极大提高COD的去除率,降低UV254和色度,同时提高废水的可生化性,并且在使用和处理过程中的产物对环境污染很小,是一种极为有效的预处理方法。文章结合臭氧的性能特点,综述了臭氧预氧化组合工艺在水处理中的研究进展,总结了在应用方面存在的问题,并展望了臭氧预处理的研究方向。     

不同药剂化学氧化预处理焦化废水的比选

采用次氯酸钠、臭氧及芬顿试剂化学氧化法对焦化废水进行预处理,考察了3种药剂对焦化废水CODCr、氨氮的去除效果及废水可生化性的提高。结果表明,次氯酸钠氧化处理对焦化废水中氨氮的去除率较高,但对废水可生化性的提高不大;臭氧氧化处理对焦化废水中CODCr和氨氮的去除率均较低,但对废水的可生化性提高迅速,反应3 min后废水的可生化性即可由0.068提升到0.281;采用芬顿试剂氧化处理,在较佳条件下,废水的可生化性可达到0.445,但运行成本高。综合考虑,采用臭氧氧化预处理焦化废水更具优势。     

活性炭催化臭氧氧化工艺对焦化废水可生化性的改善

预氧化工艺常用来提高难降解工业废水的可生化性,其中以芬顿、臭氧应用最多。该文对这两种工艺提高煤化工行业焦化废水可生化性的性能做了对比,并提出了活性炭臭氧催化预氧化的改进工艺。试验表明单纯芬顿和臭氧预氧化并不能改善焦化废水的可生化性,而活性炭臭氧催化预氧化可以改善焦化废水的可生化性。经活性炭臭氧催化预氧化的焦化废水,BOD5/COD从0.16增加到0.24,COD去除率从72.5%提高到83.0%。     

金属协同臭氧催化氧化技术研究进展

金属协同臭氧催化氧化法是最近几年发展起来的一种新型高效的高级氧化技术。根据所使用的催化剂的形态不同,该技术可分为均相协同催化臭氧化与非均相协同催化臭氧化,具有高效,快捷,无二次污染等优点,在难生化有机废水预处理,生化尾水深度处理和有机废水削减处理等方面均取得了良好的效果。     

烟气脱硫含胺废水预处理技术

对有机胺法烟气脱硫装置运转过程中的碱性含胺废水处理技术进行了研究。考察了臭氧氧化技术、絮凝技术用于含胺废水处理的效果,结果表明:(1)臭氧氧化技术用于含胺废水预处理是合适的,臭氧能够将废水中难以生化降解的有机胺转化为可以生化处理的低分子物质,同时去除大部分COD。(2)经臭氧氧化处理后,废水中的有机胺完全降解,其中有机氮几乎完全转化为NO-3。(3)SE525和SE601絮凝剂在含胺废水中絮凝效果较好,絮凝时间短,可应用于碱性含胺废水预处理絮凝脱除颗粒物。(4)经臭氧氧化后的废水经中和、絮凝、沉降,可以送污水处理场,不会对现有污水处理系统产生影响。     

臭氧氧化法预处理焦化废水的试验研究

为了提高焦化废水的可生化性,对焦化废水进行了臭氧氧化预处理的试验研究.结果表明:当废水初始pH值为9,气水反应时间为3 min,臭氧投加量为30 mg/L时,废水m(BOD5)/m(CODCr)值由原水的0.068提高到0.281.臭氧用于焦化废水的预处理是可行的,有利于焦化废水的后续生化处理.     

臭氧氧化协同预处理/深度处理单元对医药废水污染物的去除效果研究

医药废水是一种浓度高、可生化性差的难降解废水。本研究医药废水采用“混凝气浮+臭氧氧化+水解酸化”的强化预处理处理方式,有效地促进了生物处理单元对COD的去除,COD平均去除率为86.8%,其次为TN、TP,用以改善可生化性较差的废水进水条件;深度处理中臭氧氧化能够将经生物处理单元处理后废水中残余有机物氧化,结合“砂滤”和“活性炭吸附”单元可以强化系统对COD的去除效果;预处理、深度处理中臭氧投加量分别达到60 g/m³、70 g/m³时,系统处理效果良好。     

电渗析离子交换膜污染控制措施研究

为了解决电渗析技术处理垃圾渗滤液MBR产水过程中的膜污染问题，采用电絮凝和臭氧氧化2种预处理方式对MBR产水进行预处理，考察2种预处理方式对离子交换膜污染的控制效果。研究结果表明，经过电絮凝预处理后的废水COD和吸光度分别降低26.1%、 14.5%，经过臭氧氧化预处理后的废水COD和吸光度分别降低28.0%、 87.8%，电絮凝和臭氧氧化预处理使得膜电阻比没有经过预处理时分别下降了7.74%和52.87%，臭氧氧化预处理对电渗析过程中膜污染现象的预防效果优于电絮凝技术；采用pH值为11的NaOH溶液可以有效地恢复离子交换膜的性能，清洗后的膜电阻和脱盐效率均可以恢复到初始状态。     

氧化预处理技术在农药废水处理中的应用研究进展

随着农药废水中难生物降解化合物的增加．常规的生化处理方法无法完全去除水巾的污染物。因此,有必要通过氧化方法对难生化降解的农药废水进行预处理,使废水中的难生化降解物质转化为易于生化处罢的小分子化合物。氧化预处理农药废水的技术包括：化学氧化（包括二氧化氯和臭氧氧化）、芬顿法、光催化氧化法和湿式氧化法（包括湿式氧化、催化湿式氧化、超临界催化湿式氧化和催化湿式过氧化）。重点介绍     

臭氧催化氧化技术在水处理中的应用

臭氧催化氧化技术室一种高级氧化技术,具有氧化效率高,对有机物的处理效果好,可提高生化性等特点。本文重点阐述了臭氧催化氧化技术在含油废水、工业废水、食品废水以及饮用水处理方面的应用,并指出了臭氧催化氧化技术存在的问题。     

Flocculation Effects of Ozone

There are numerous reports on coagulation/flocculation effects of preozonation, which cannot be interpreted by one single mechanism. About 7 basic processes are presently discussed. This paper presents results from drinking and wastewater treatment, indicating that preozonation effects can be explained with algae flocculation, with the destabilization of particles, and with polymerization of the dissolved organics. In view of the complexity of the systems, it is anticipated that several processes can be responsible, leading to an optimum ozone dosage.     

The Effects of Preozonation on the Biodegradability of Phenolic Solutions Using a New Gas-Inducing Reactor

To achieve effective COD removal, the combination of preozonation with biological treatment is necessary for phenolic wastewater treatments. Preozonation of 4-cresol, 2-chlorophenol and 4-nitrophenol solutions can be carried out with high ozone utilization rate using a new gas-inducing reactor. During the preozonation, the phenolic compounds can be completely decomposed with 100% ozone utilization rate. This new gas-inducing reactor is beneficial for the preozonation of phenolic solutions, comparing with a conventional gas-liquid reactor. The BOD₅ of preozonized phenolic solution is strongly related to both the degree of decomposition of phenolic compounds and the accumulation of intermediate products in aqueous solution. Based on the high ozone utilization rate, it is suggested that the optimal utilized ozone dose for 4-cresol, 2-chlorophenol and 4-nitrophenol can be chosen as 360, 350 and 400 mg/L, respectively. At those optimal utilized ozone doses, the ratio of BOD₅/COD of preozonized 4-cresol, 2-chlorophenol and 4-nitrophenol solutions increase to 0.33, 0.26 and 0.33, respectively.     

Impact of chemical oxidation on biological treatment of a primary municipal wastewater. 2. Effects of ozonation on kinetics of biological oxidation

Activated sludge biological oxidation of municipal wastewaters has been applied under different experimental conditions to observe the effect of preozonation on COD and process kinetics. In all cases, previous application of ozone allows significant improvement of COD level reduction during subsequent biological oxidation. Biomass concentration also exerts a positive influence on COD level reduction. Thus, 54 and 82% COD level reductions are achieved after biological oxidation without and with 30 minutes of preozonation. During the ozonation period, increase of pH from 2 to 9 leads to 15 to 24% COD level reductions, but biological oxidation should be followed at neutral pH since extreme conditions (pH 2 and 9) reduce considerably the biomass concentration and hence the yield of biodegradation. At the conditions investigated herein, there is an optimum ozone dose, 150 mg per liter of wastewater treated, that leads to the maximum COD level reduction in the combined process (chemical plus biological oxidation). Both single biological oxidation and combined with preozonation follows a Monod kinetic model assuming COD as the substrate of biomass. From kinetic results it is confirmed that a combination of chemical and biological oxidation leads to the highest maximum specific rates of COD consumption.     

Ozonation and Precipitation for Treatment of Bleachery Effluents from Pulp Mills

Results from precipitation of an oxygen/peroxide-bleachery effluent from pulp mills with and without preozonation are presented. Reductions in DOC levels by about 60% were achieved at the pH optimum of 5.5 at an AI/D0C ratio of 0.25 g/g. Increasing alum dosages did not improve the elimination. Ozonation at pH 2 reduced COD, DOC, UV and color levels, while under alkaline conditions an increase of color could be obtained. This effect, based on a polymerization of organics, could be improved at low ozone dosages, by reducing the ozone dosage rate, elevating the pH up to 11 and diluting the wastewater. However, the shift towards high and low molecular weight fractions indicated competing degradation reactions, which counteract a suggested improvement of precipitation by preozonation.     

焦化厂生化外排水的臭氧强化混凝实验研究

针对某焦化厂废水生化处理系统中混凝沉淀效果不佳,出水COD过高的问题,采用多因素的优化正交实验设计,对焦化生化出水进行了臭氧辅助混凝的实验研究,确定了该废水混凝沉淀最适宜的混凝剂、搅拌条件、投加剂量以及臭氧预处理时间等。研究表明,适当时间的臭氧预处理可以很好的强化混凝沉淀效果,提高废水中COD的去除率和降低色度。     

Biodergradability and GAC Adsorbability of Micropollutants by Preozonation

In order to evaluate the effect of preozonation on GAC adsorbability and biodegradability and to discuss the performance of BAC, three kinds of batch experiments have been conducted, using humic acid as the test substance. Conclusively, it is recognized that preozonation evidently improves the biodegradability of humic acid, but the equilibrium adsorption constant k, is not changed. However, the adsorption rate is greatly improved. Based on these results and continuous experiments, the characteristics of the removal mechanism of organics by a BAC filter and a GAC filter are compared.     

Impact of chemical oxidation on biological treatment of a primary municipal wastewater. 1. Effects on cod and biodegradability

Municipal wastewaters taken from a primary sedimentation tank were subjected to different chemical oxidation processes (ozonation or UV radiation alone or combined with hydrogen peroxide) to observe the evolution of COD and BOD/COD ratios. Ozonation of wastewater led to different increases of COD level reduction depending on pH and carbonate‐bicarbonate ion concentrations. Direct photolysis or hydrogen peroxide alone were found to be inappropriate technologies. On the other hand, advanced chemical oxidation, that is, oxidation with ozone or UV radiation combined with hydrogen peroxide, increased COD level reduction only when wastewater was previously decarbonated. Thus, elimination of carbonate‐bicarbonate ions, increase of pH and addition of hydrogen peroxide (10^‐3 M) yield increases COD level reduction rates. Finally, preozonation also allows improvement of wastewater biodegradability.     

Preozonation To Improve And Optimize Diatomaceous Earth Filtration

The benefits of preozonation before diatomaceous earth filtration have been demonstrated in a City of New York research program to develop design criteria for treatment of its 300 mgd Croton water supply. In the treatment of a supply where paniculate matter is predominantly of organic origin, preozonation provides two outstanding advantages that are not possible in diatomaceous earth filtration alone.     

The Preozonation of Phenolic Aqueous Solution and Its Effect on the Improvement of Coagulation Treatment

Phenolic solutions are difficult to treat with coagulation processes because phenol is well soluble in water. However, with suitable preozonation, the ozonized organic components can be removed more effectively by coagulation processes. In order to avoid excessive preozonation, a good control on the degree of preozonation is crucial for practical applications. The degree of preozonation of phenolic solution was evaluated by measuring the phenol decomposition rate, ADMI value and ozone outlet concentration during the ozonation. Three characteristic times were observed, namely (1) ADMI value reaches the peak value during preozonation, (2) the ozone outlet concentration starts increasing, and (3) the ADMI value reaches the discharge standard (500 value, EPA Taiwan). These characteristic times provide the useful means as real-time control parameters on the extent of preozonation. The results of HPLC and GPC show that phenol is almost completely decomposed after 43?min of preozonation. The major components after preozonation are oxalic acid and coupling compounds. The preozonized solution, containing phenol decomposition products, was then subjected to coagulation treatments. The coagulation behavior of preozonized solution is dependent on the extent of preozonation. Three types of coagulant were investigated, namely alum, ferric chloride (FeCl₃) and poly aluminum chloride (PAC). Both PAC and FeCl₃ are effective coagulants for COD removal. As an example, phenol solution (initial phenol concentration=300?mg/L, C _{O 3},i=20?mg/L) was preozonized for 50 minutes, followed by FeCl₃ coagulation treatment. After preozonation and coagulation processes, the total COD and ADMI removal rates are as high as 70% and 80%, respectively. Most of the coupling compounds and oxalic acid are removed by the coagulant.     

Ozone Assisted Biological Treatment Of Industrial Wastewaters Containing Biorefractory Compound

Ozone pretreatment studies of organic compounds that are difficult to biodegrade were conducted to evaluate the effects of ozonation on biodegradability of these compounds. Initial testing was conducted in batch activated sludge experiments with and without preozonation to evaluate the impacts of ozonation on the ultimate BOD/COD and ultimate BOD/TOC ratios of these compounds. Experimental results indicated wastewater preozonation to be an effective pretreatment step for some compounds, ineffective for other compounds and detrimental to biological treatment of still other compounds. These same compounds were then investigated in continuous flow, complete–mix activated sludge systems. Complete material balances, including influent, effluent, waste sludge and off–gas specific compound analyses, were conducted so that the actual fate of the compound could be determined. Removal mechanisms of the ozonated or unozonated compound were then determined to be biodegradation, stripping, or sorption to the biomass. Three compounds were investigated: acrylonitrile, 2,4 dinitrophenol, and 1,2 dichloropropane.