Satellite derived trends in NO2 over the major global hotspot regions during the past decade and their inter-comparison

We assessed satellite derived tropospheric NO₂ distribution on a global scale and identified the major NO₂ hotspot regions. Combined GOME and SCIAMACHY measurements for the period 1996-2006 have been used to compute the trends over these regions. Our analysis shows that tropospheric NO₂ column amounts have increased over the newly and rapidly developing regions like China (11 ± 2.6%/year), south Asia (1.76 ± 1.1%/year), Middle East (2.3 ± 1%/year) and South Africa (2.4 ± 2.2%/year). Tropospheric NO₂ column amounts show some decrease over the eastern US (−2 ± 1.5%/year) and Europe (0.9 ± 2.1%/year). We found that although tropospheric NO₂ column amounts decreased over the major developed regions in the past decade, the present tropospheric NO₂ column amounts over these regions are still significantly higher than those observed over newly and rapidly developing regions (except China). Tropospheric NO₂ column amounts show some decrease over South America and Central Africa, which are major biomass burning regions in the Southern Hemisphere.     

Effect of selected organic and inorganic snow and cloud components on the photochemical generation of nitrite by nitrate irradiation

The effect of selected organic and inorganic compounds, present in snow and cloudwater was studied. Photolysis of solutions of nitrate to nitrite was carried out in the laboratory using a UVB light source. The photolysis and other reactions were then modelled. It is shown that formate, formaldehyde, methanesulphonate, and chloride to a lesser extent, can increase the initial formation rate of nitrite. The effect, particularly significant for formate and formaldehyde, is unlikely to be caused by scavenging of hydroxyl radicals. The experimental data obtained in this work suggest that possible causes are the reduction of nitrogen dioxide and nitrate by radical species formed on photooxidation of the organic compounds. Hydroxyl scavenging by organic and inorganic compounds would not affect the initial formation rate of nitrite, but would protect it from oxidation, therefore, increasing the concentration values reached at long irradiation times. The described processes can be relevant to cloudwater and the quasi-liquid layer on the surface of ice and snow, considering that in the polar regions irradiated snow layers are important sources of nitrous acid to the atmosphere. Formate and (at a lesser extent) formaldehyde are the compounds that play the major role in the described processes of nitrite/nitrous acid photoformation by initial rate enhancement and hydroxyl scavenging.     

Integrated catalytic wet air oxidation and aerobic biological treatment in a municipal WWTP of a high-strength o-cresol wastewater

This study examines the feasibility of coupling a Catalytic Wet Air Oxidation (CWAO), with activated carbon (AC) as catalyst, and an aerobic biological treatment to treat a high-strength o-cresol wastewater. Two goals are pursued: (a) To determine the effect of the main AC/CWAO intermediates on the activated sludge of a municipal WasteWater Treatment Plant (WWTP) and (b) To demonstrate the feasibility of coupling the AC/CWAO effluent as a part of the influent of a municipal WWTP. In a previous study, a high-strength o-cresol wastewater was treated by AC/CWAO aiming to establish the distribution of intermediates and the biodegradability enhancement. In this work, the biodegradability, toxicity and inhibition of the most relevant intermediates detected in the AC/CWAO effluent were determined by respirometry. Also, the results of a pilot scale municipal WWTP study for an integrated AC/CWAO-aerobic biological treatment of this effluent are presented. The biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) of main AC/CWAO intermediates allowed the classification of the intermediates into readily biodegradable, inert or toxic/inhibitory compounds. This detailed study, allowed to understand the biodegradability enhancement exhibited by an AC/CWAO effluent and to achieve a successful strategy for coupling the AC/CWAO step with an aerobic biological treatment for a high-strength o-cresol wastewater. Using 30%, as COD, of AC/CWAO effluent in the inlet to the pilot scale WWTP, the integrated AC/CWAO-biological treatment achieved a 98% of total COD removal and, particularly, a 91% of AC/CWAO effluent COD removal without any undesirable effect on the biomass.     

Dioxin formation in pulp and paper mills of India

Samples of effluents, sludge, pulp, final products (paper) and soil were collected from the identified pulp and paper mills in India. The samples were analysed for 2,3,7,8-tetrachloro-dibenzo-p-dioxin (2,3,7,8-TCDD) and other dioxin congeners and precursors. Pulp and paper mills using chlorine for the bleaching process showed the presence of 2,3,7,8-TCDD in effluent samples. In the effluent and pulp samples from mills where chlorine dioxide was used as a bleaching agent, the 2,3,7,8-TCDD congener ranged from below the detection limit 0.05 to 0.12 ngL⁻¹/ngg⁻¹. The relative standard deviation of reproducibility and the percent recovery of 2,3,7,8-TCDD were 2.07 and 82.4% in pulp and 2.8 and 92% in effluent, respectively. The 1,3,6,8-TCDD was the only other major dioxin congener found in the treated and untreated effluent and sludge samples. However, dichlorobenzene, trichlorophenyl, and hexachlorobiphenyl were detected in all samples. The formation of dioxins can be minimised by replacing chlorine with chlorine dioxide in bleaching processes in pulp and paper mills.     

厌氧-好氧工艺处理制药废水的中试研究

将由厌氧折流板反应器(ABR)、移动床生物膜反应器(MBBR)和膜生物反应器(MBR)组合而成的厌氧-好氧工艺用于处理制药废水的中试研究.试验结果表明,当原水SS平均值为1000 mg/L,COD为10 000 mg/L,NH3-N为500 mg/L时,出水浊度、COD和NH3-N分别为3 NTU、500 mg/L以及10 mg/L以下,去除率分别为98%、95%和98%以上.     

排污申报数据审核的一般方法

排污申报登记工作具有数据量大、逻辑性强、专业要求高的特点,环保部门必须力求通过强化数据的审核来获得完整、准确的排污申报数据。     

区域污染物总量控制绩效评估技术及动态化管理建议与对策研究（二）

首次指出了物元分析隶属函数及运算模型在区域污染物总量控制动态化管理中的应用.研究成果是对扬州市的10年污染物总量控制系统性、宏观性的展开,丰富了区域污染物总量控制的理论体系,且进一步表明：该成果不仅为污染物总量控制进行动态化、规范化管理提供了科学的技术支撑,也为促进区域经济结构调整和增长方式的转变,实施循环经济的决策提供了保障.     

沭阳县水环境安全管理与污染防治对策探讨

在简要介绍沭阳县水环境概况后,着重分析了该县的水污染现状和主要的水环境问题,并针对性地提出了一些水环境安全管理和污染防治的建议,建立淮河流域水环境安全协调机制和沭阳水环境保护机制,完善水质监测,加强工业、农业和生活污染的防治,建立清污分流系统,并加强宣传教育等项工作.     

印染废水集中处理工程的实例分析

针对印染企业集中园区产生的综合废水复杂多变,必要选择合式的处理工艺,因此,以某印染企业集中园区的污水处理厂为例,采用厌氧＋好氧＋物化组合工艺,并对废水的脱色和可生化性的改善进行了试验研究,通过类比调查,优化工程设计参数;经工程实践证明,综合印染废水经该工艺处理后,能达到一级排放标准.     

VFAs、TOC及COD作为生物除磷能力指标的探讨

在实际生活污水的处理中,研究了通过A/O运行模式对生物除磷过程中磷的变化情况及在厌氧释磷过程中COD、TOC与VFAs变化之间的关系。结果表明,在厌氧释磷过程中VFAs的变化更能准确地反映系统内释磷进程,实际生活污水中能直接用于磷释放的有机物含量占COD的13.33%,并且释放1 mg P所需VFAs为1.401 mg,此值明显低于前期研究结果。通过对COD、TOC和VFAs 3种组分的分析,可将实际生活污水中的有机底物分为3类:易生物降解含碳有机物、难降解的含碳有机物和水中存在的无机性还原物质,含量分别占COD的13.33%、31.7%和54.97%,其中只有13.33%的含量对生物释磷有直接作用,并可对实际生活污水除磷有指导意义。