Kinetics of microbial landfill methane oxidation in biofilters

A methane oxidizing biofilter system fitted to the passive venting system of a harbor sludge landfill in Germany was characterized with respect to the the methanotrophic population, methane oxidizing capacity, and reaction kinetics. Methanotrophic cell counts stabilized on a high level with 1.3 x 10(8) to 7.1 x 10(9) cells g dw(-1) about one year after first biofilter operation, and a maximum of 1.2 x 10(11) cells g dw(-1). Potential methane oxidizing activity varied between 5.3 and 10.7 microg h(-1) g dw(-1). Cell numbers correlated well with methane oxidation activities. Extrapolation of potential activities gave methane removal rates between 35 and 109 g CH4 h(-1) m(-3), calculated for 30 degrees C. Optimum temperature was 38 degrees C for freshly sampled biofilter material and 22 degrees C for a methanotrophic enrichment culture grown at 10 degrees C incubation temperature. Substrate kinetics revealed the presence of a low-affinity methane oxidizing community with a high Vmax of 1.78 micromol CH4 h(-1) g ww(-1) and a high K(M) of 15.1 microM. K(MO2) for methane oxidation was 58 microM. No substantial methane oxidizing activity was detected below 1.7-2.6 vol.-% O2 in the gaseous phase. Methane deprivation led to a decrease in methane oxidation activity within 5-9 weeks but could still be detected after 25 weeks of substrate deprivation and was fully restored within 3 weeks of continuous methane supply. Very high salt loads are leached from the novel biofilter material, expanded clay, yielding electric conductivity values of up to 15 mS cm(-1) in the leachate. Values > 6 mS cm(-1) were shown to depress methane consumption. Water retention characteristics of the material proved to be favourable for methane oxidizing systems with a gas permeable volume of 78% of bulk volume at field capacity water content. Correspondingly, no influence of water content on methane oxidation activity could be detected at water contents between 2.5 and 20 vol.-%.     

中国南部四背景地区春季大气碳质气溶胶特征与来源

春季分别同时在中国南方4个背景地区(海南尖峰岭、香港鹤嘴、浙江临安和云南腾冲)进行大气加密观测实验,并分析其大气中PM2.5质量浓度及其碳质颗粒组分(有机碳(OC)、元素碳(EC)和左旋葡聚糖).结果表明,各区域背景站点由于受不同污染源及传输过程影响而呈现出不同的特征:西南部腾冲站点与东部临安站点由于分别受到生物质燃烧和化石燃料燃烧等一次污染源的主导影响,而形成高OC、EC水平特征,且经受体示踪物方法估算腾冲站点受生物质燃烧对其OC的贡献均值可达到73%;尖峰岭站点由于二次污染及活跃的生物活动的共同作用,表现了高OC/EC比值及低碳质颗粒物浓度的特征,而鹤嘴站点则主要受海洋气团影响呈现出低碳质颗粒浓度与两两呈高度相关的特点,反映了其所在区域春季的背景特征.     

北京市大气气溶胶中糖类化合物的组成及来源

采用高效阴离子交换色谱-脉冲安培检测(HPAEC-PAD)分析方法,对北京城区PM2.5和PM10中糖类化合物进行定量分析.在北京大气气溶胶中共检出14种糖类化合物,分为脱水糖、糖和糖醇共3大类.脱水糖包括左旋葡聚糖、甘露聚糖和半乳聚糖;糖包括葡萄糖、果糖和海藻糖;糖醇包括阿拉伯糖醇、甘露糖醇、丙三醇、苏糖醇、2-甲基丁四醇(2-甲基苏糖醇和2-甲基赤藓糖醇)、木糖醇和肌醇.脱水糖来源于生物质燃烧,秋冬季节的浓度水平明显高于春夏;而来源于生物源排放的糖和糖醇,冬季浓度水平明显低于其它季节.PMF源解析结果表明,北京大气气溶胶中糖类化合物的来源主要可以分为6类,包括生物质燃烧、异戊二烯SOA、土壤悬浮、真菌孢子、花粉及丙三醇富集源.     

Levoglucosan and carbonaceous species in the background aerosol of coastal southeast China: case study on transport of biomass burning smoke from the Philippines

Introduction  

Levoglucosan and carbonaceous species in the background aerosol of coastal southeast China were measured at Jianfengling (JFL), a background mountain site in a National Reserve Park on Hainan Island, and at Hok Tsui (HT), a rural site on the southern coast of Hong Kong from April to May of 2004 during an intensive field study.     

Minerals policy in Europe: Some recent developments

The importance of a secured supply of raw materials for the European economy is evident. However, securing the supply of raw materials based on an appropriate EU minerals policy has been scarcely treated by the decision-makers in the last decades. Solely the impact of price development of international commodity markets in the last years induces a re-thinking of this field. The EU Raw Materials Initiative, which was published by the European Commission in November 2008, establishes an EU raw materials strategy including a list of actions.     

Temporal variation and impact of wood smoke pollution on a residential area in southern Germany

This paper is a continuation of our previous publication (Bari, M.A., Baumbach, G., Kuch, B., Scheffknecht, G., 2009. Wood smoke as a source of particle-phase organic compounds in residential areas. Atmospheric Environment 43, 4722–4732) and describes a detailed characterisation of different particle-phase wood smoke tracer compounds in order to find out the impact of wood-fired heating on ambient PM₁₀ pollution in a residential area near Stuttgart in southern Germany. The results from previous flue gas measurements help distinguishing different tracer compounds in ambient PM₁₀ samples. In the residential area, significant amounts of hardwood markers (syringaldehyde, acetosyringone, propionylsyringol, sinapylaldehyde) and low concentrations of softwood markers (vanillin, acetovanillone, coniferyldehyde, dehydroabietic acid, retene) were found in the ambient air. The general wood combustion markers Levoglucosan, mannosan and galactosan were detected in high concentrations in all particle-phase PM₁₀ samples. To find out the size distribution of ambient particles, cascade impactor measurements were carried out. It was found that more than 70% of particulate matter was in the particle diameter of less than 1 μm. Using emission ratio of levoglucosan to PM₁₀, it can be demonstrated that during winter months 59% of ambient PM₁₀ pollution could be attributed to residential wood-fired heating.