臭氧预氧化处理葡萄酒废水

葡萄酒废水的季节性波动常造成生化处理系统不稳定,使传统的生化处理工艺难以满足新的污水排放标准的要求。研究了臭氧预处理工艺对葡萄酒废水的处理效果及主要控制参数,结果表明,单独的臭氧预氧化对COD几乎无去除效果,但对色度的去除可达到90%;采用O3/H2O2组合工艺可使COD的去除率提高4倍。经臭氧预处理的出水再采用SBR进行好氧处理时,出水COD能降至80 mg/L以下,COD的降解速度及程度都高于未经臭氧处理的稀释原水。高效液相色谱(HPLC)分析显示,经臭氧处理后,除麦芽糖成分被完全去除外,其他各种成分的数量变化不大;GC/MS对废水中多酚类有机物的分析显示,臭氧预处理可将大量难降解的多酚类有机物分解,从而有助于后续生化处理的出水达到更高的污水排放标准。     

Atmospheric Deposition and Ozone Levels in Swiss Forests: Are Critical Values Exceeded?

Air pollution affects forest health through atmospheric deposition of acidic and nitrogen compounds and elevated levels of tropospheric ozone (O₃). In 1985, a monitoring network was established across Europe and various research efforts have since been undertaken to define critical values. We measured atmospheric deposition of acidity and nitrogen as well as ambient levels of O₃ on 12, 13, and 14 plots, respectively, in the framework of the Swiss Long-Term Forest Ecosystem Research (LWF) in the period from 1995 to 2002. We estimated the critical loads of acidity and of nitrogen, using the steady state mass balance approach, and calculated the critical O₃ levels using the AOT40 approach. The deposition of acidity exceeded the critical loads on 2 plots and almost reached them on 4 plots. The median of the measured molar ratio of base nutrient cations to total dissolved aluminium (Bc/Al) in the soil solution was higher than the critical value of 1 for all depths, and also at the plots with an exceedance of the critical load of acidity. For nitrogen, critical loads were exceeded on 8 plots and deposition likely represents a long-term ecological risk on 3 to 10 plots. For O₃, exceedance of critical levels was recorded on 12 plots, and led to the development of typical O₃-induced visible injury on trees and shrubs, but not for all plots due to (1) the site specific composition of O₃ sensitive and tolerant plant species, and (2) the influence of microclimatic site conditions on the stomatal behaviour, i.e., O₃ uptake.     

Seasonal differences and within-canopy variations of antioxidants in mature spruce (Picea abies) trees under elevated ozone in a free-air exposure system

The effect of free-air ozone fumigation and crown position on antioxidants were determined in old-growth spruce (Picea abies) trees in the seasonal course of two consecutive years (2003 and 2004). Levels of total ascorbate and its redox state in the apoplastic washing fluid (AWF) were increased under double ambient ozone concentrations (2xO3), whilst ascorbate concentrations in needle extracts were unchanged. Concentrations of apoplastic and symplastic ascorbate were significantly higher in 2003 compared to 2004 indicating a combined effect of the drought conditions in 2003 with enhanced ozone exposure. Elevated ozone had only weak effects on total glutathione levels in needle extracts, phloem exudates and xylem saps. Total and oxidised glutathione concentrations were higher in 2004 compared to 2003 and seemed to be more affected by enhanced ozone influx in the more humid year 2004 compared to the combined effect of elevated ozone and drought in 2003 as observed for ascorbate.     

Background ozone levels of air entering the west coast of the US and assessment of longer-term changes

An analysis of surface ozone measurements at a west coast site in northern California (Trinidad Head) demonstrates that this location is well situated to sample air entering the west coast of the US from the Pacific Ocean. During the seasonal maximum in the spring, this location regularly observes hourly average ozone mixing ratios 50 ppbv in air that is uninfluenced by the North American continent. Mean daytime values in the spring exceed 40 ppbv. A location in southern California (Channel Islands National Park) demonstrates many of the characteristics during the spring as Trinidad Head in terms of air flow patterns and ozone amounts suggesting that background levels of ozone entering southern California from the Pacific Ocean are similar to those in northern California. Two inland locations (Yreka and Lassen Volcanic National Park) in northern California with surface ozone data records of 20 years or more are more difficult to interpret because of possible influences of local or regional changes. They show differing results for the long-term trend during the spring. The 10-year ozone vertical profile measurements obtained with weekly ozonesondes at Trinidad Head show no significant longer-term change in tropospheric ozone.     

臭氧降解有机污染物的反应机理及影响因素

论述了臭氧氧化有机污染物的反应机理,探讨了臭氧氧化反应的主要影响因素,及臭氧氧化反应器的材质要求,并对臭氧氧化技术在实践中的应用提出了基本的设计思路。     

Tree and stand growth of mature Norway spruce and European beech under long-term ozone fumigation

In a 50- to 70-year-old mixed stand of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) in Germany, tree cohorts have been exposed to double ambient ozone (2×O₃) from 2000 through 2007 and can be compared with trees in the same stand under the ambient ozone regime (1×O₃). Annual diameter growth, allocation pattern, stem form, and stem volume were quantified at the individual tree and stand level. Ozone fumigation induced a shift in the resource allocation into height growth at the expense of diameter growth. This change in allometry leads to rather cone-shaped stem forms and reduced stem stability in the case of spruce, and even neiloidal stem shapes in the case of beech. Neglect of such ozone-induced changes in stem shape may lead to a flawed estimation of volume growth. On the stand level, 2×O₃ caused, on average, a decrease of 10.2 m³ ha⁻¹ yr⁻¹ in European beech.     

MCR—O_3—BAC组合工艺在工业园区污水处理厂提标改造中的运用研究

以膜混凝反应器(MCR)—O3—生物活性炭(BAC)组合工艺作为出水提标改造工艺,在浙江某工业园区污水处理厂进行了现场试验,考察了组合工艺对有机物和色度的去除情况,并验证了膜过滤(MCR工艺段)在组合工艺中的作用。结果表明,MCR工艺段对COD和色度均有不同程度的去除,去除效果均与进水SS浓度有关;MCR—O3—BAC组合工艺运行中,COD去除率最高的是在BAC工艺段,稳定运行阶段(70~90d左右,下同)最终出水COD基本不超过50mg/L,色度去除率最高的主要是在O3工艺段,去除率达到37.5%~68.8%,稳定运行阶段最终出水色度小于30倍,均符合《城镇污水处理厂污染物排放标准》(GB18918—2002)一级A标准;通过定期的清洗维护,MCR系统中膜可以在35L/(m2·h)的通量下稳定运行,维护性清洗周期为20~30d;MCR工艺段的引入可以显著减少O3的消耗量。     

畜禽养殖废水生物处理剩余污泥臭氧减量过程中的重金属释放

采用臭氧氧化污泥减量法对畜禽养殖废水SBR中的剩余污泥进行处理。当臭氧反应时间控制在30min时,污泥的溶解比例在30％左右（以MLSS计）。上清液中一定量的SCOD溶出可为生物处理单元提供充足的碳源,同时在上清液中,TN、TP及水相重金属浓度增加有限,臭氧氧化后的污泥液回流污水处理系统后造成的N、P处理负荷较小,重金属对污泥微生物的活性抑制风险较低。若继续延长臭氧的反应时间,上清液SCOD、TN、TP以及重金属cu、Pb的释放速率明显增加,同时上清液的C／N降低,臭氧化后的污泥液回流反而不利于生物单元的脱氮处理。综合考虑TN、TP及水相重金属浓度增加的危害性,臭氧反应时间应控制在30min,臭氧实际投加量应为123．1mg O3／gSS。     

通风、过氧乙酸和臭氧氧化降低室内空气微生物

为了防止室内空气微生物导致的传染病发生 ,对某校园室内的空气进行通风、过氧乙酸和臭氧灭菌降低微生物的实验研究结果表明 ,通风可以有效地降低室内微生物的浓度 ,是最为经济和易行的措施 ;过氧乙酸灭菌效果好 ,持续时间较长 ,可在不易实施通风情况下采用过氧乙酸灭菌 ;臭氧具有迅速杀菌的效果 ,使用时要与人保持一定距离 ,最好超出 1m。本研究为合理实施改善室内空气卫生环境提供了参考数据 ,3种降低室内空气微生物的方法各有其效和特点 ,使用时应根据具体情况选定     

长江三角洲夏季一次典型臭氧污染过程的模拟

利用WRF/Chem空气质量模式对长江三角洲夏季一次典型臭氧(O3)污染过程的时空分布特征和物理化学机制进行了数值模拟研究.结果表明,模式能够合理地再现这次长江三角洲夏季典型O3污染过程的时空分布特征和演变规律.2013年8月10~18日,长江三角洲主要受副热带高压影响,晴天、高温和小风的气象条件有利于光化学污染的形成.模拟结果表明,长江三角洲地区气象场、地理位置、区域输送和化学生成都对O3的时空分布有影响.敏感性实验表明,上海O3浓度在海洋性气流影响下较低,但上海排放源对长江三角洲O3浓度时空分布的影响较为显著;南京近地面高浓度O3主要贡献为化学生成(烯烃和芳香烃)和高层O3的垂直输送,杭州和苏州近地面高浓度O3主要来源于物理过程.在O3生成速率最大时(11~13h)对O3前体物减排,对长江三角洲15:00的O3峰值浓度影响较为明显.