Comparisons of Measured and Modelled Ozone Deposition to Forests in Northern Europe

The performance of a new dry deposition module, developedfor the European-scale mapping and modelling of ozone flux to vegetation, was tested against micrometeorological ozone and water vapour flux measurements. The measurement data are for twoconiferous (Scots pine in Finland, Norway spruce in Denmark) and one deciduous forest (mountain birch in Finland). On average, themodel performs well for the Scots pine forest, if local inputdata are used. The daytime deposition rates are somewhat over-predicted at the Danish site, especially in the afternoon. The mountain birch data indicate that the generic parameterisationof stomatal responses is not very representative of this northernspecies. The module was also tested by using modelled meteorological data that constitute the input for a photochemical transport model.     

采出水处理回用高通量膜法技术

针对某低渗透油田企业采出水,开展了现场膜处理小试实验,考察了采用膨化聚四氟乙烯(ePTFE)微滤膜工艺处理采出水达到回注标准的技术可行性,确定了膜前过滤介质及其最佳浓度,并就实际应用进行了工艺设计.采用膜前过滤介质,避免了采出水中的石油类物质对膜产生污堵等负面影响.膜前过滤介质为吸附性介质硅藻土与刚性颗粒介质碳酸钙复配...     

某核废液处理厂的火灾爆炸事故解析(Ⅱ) 氧化剂盐粒子的大小及微观结构对沥青固化物的固—液表面氧化还原反应特性的影响

就不同粒径及微观构造的氧化剂盐粒子制备的沥青固化物的氧化还原反应特性用高感度量热仪(C80微量量热仅)进行了测定.结果表明,当氧化剂盐粒子的微观构造基本相同时,随粒径的减小,制作的沥青固化物的反应开始温度向低温方向偏移,低温领域的发热量增大.当粒径的大小及其分布基本相同时,沥青固化物的氧化还原反应特性随粒子的微观构造的不同表现出较大的差异,由针状结晶构成的多孔状粒子制成的沥青固化物的反应开始温度低、低温领域的发热量较大.     

广州城市污泥中重金属的含量、排放通量及农用风险评价

分析了广州市中心城区5个主要的污水处理厂污泥的基本理化性质和7种重金属(Cr、Cu、Mn、Ni、Pb、Cd和Zn)在不同雨期的浓度变化,估算了广州市污水处理厂污泥重金属的年排放通量,并对其污泥农用做了潜在风险评价。结果表明,各污水厂污泥均达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)对重金属的排放要求,污泥的基本理化性质满足《城镇污水处理厂污泥处置农用泥质》(CJ/T309-2009)标准,沥滘、猎德、京溪和大坦沙污水厂的污泥重金属满足CJ/T309-2009要求,而西朗污水处理厂2013年12月采集的污泥中Cu和Cd未达标。通过估算,广州市污水处理厂污泥中Cr、Cu、Mn、Ni、Pb、Cd和Zn的年排放通量分别为16.1、18.8、90.3、5.9、7.9、0.2和48.3 t。通过Hakanson生态风险评估,污泥在农用过程中除西朗污水处理厂污泥重金属危害为中等风险,其他厂污泥属于低风险。     

城市污水处理厂甲烷的释放通量

通过对山东省济南市某城市污水处理厂所有处理单元的采样监测,分析研究了污水处理过程中CH4的释放通量。结果表明,该污水处理厂主要的CH4释放单元包括厌氧池、好氧池、缺氧池和二沉池,其中,厌氧池是最主要的CH4释放单元,释放量约占到全厂的50%。经测算,该污水处理厂每年释放CH4约12 600 kg,CH4的人均释放系数为31.5 g/(人.yr),每处理1 t污水释放CH4334.6 mg。COD浓度可能是影响厌氧池CH4产生和释放的重要因素,在实验监测范围内,高COD浓度可能会促进CH4的释放。     

基于改进混合遗传-支持向量机的CMF产水预测研究

将模拟退火思想和加速遗传特性相结合,改进选择策略和遗传算子,建立加速遗传模拟退火算法（AGSA）;基于支持向量机（SVM）的非线性回归和改进混合遗传算法的因子筛选,构造了支持向量机模型参数的自适应优化算法,提出连续微滤系统（CMF）产水预测模型;通过实测中试规模连续微滤系统产水量变化对模型进行验证,结果表明：该模型较好...     

膜生物反应器处理不同浓度生活污水的研究

通过对毛细管膜在不同浓度的污泥条件下 ,处理生活污水时膜污染情况的研究 ,考察了膜组件水通量随污泥浓度而变化的情况。结果表明 ,在操作压力为 0 .0 2 5MPa、膜面流速为 0 .8m s和温度为 30℃的条件下 ,污泥浓度增大 ,膜水通量随之下降 ,并与污泥浓度呈对数关系。同时 ,表明导致膜污染水通量下降的主要原因为泥饼阻力     

Net ecosystem CO2 exchange over a larch forest in Hokkaido, Japan

Larch forests are distributed extensively in the east Eurasian continent and are expected to play a significant role in the terrestrial ecosystem carbon cycling process. In view of the fact that studies on carbon exchange for this important biome have been very limited, we have initiated a long-term flux observation in a larch forest ecosystem in Hokkaido in northern Japan since 2000. The net ecosystem CO₂ exchange (NEE) showed large seasonal and diurnal variation. Generally, the larch forest ecosystem released CO₂ in nighttime and assimilated CO₂ in daytime during the growing season from May to October. The ecosystem started to become a net carbon sink in May, reaching a maximum carbon uptake as high as 186 g C m⁻² month⁻¹ in June. With the yellowing, senescing and leaf fall, the ecosystem turned into a carbon source in November. During the non-growing season, the larch forest ecosystem became a net source of CO₂, releasing an average of 16.7 g C m⁻² month⁻¹. Overall, the ecosystem sequestered 141–240 g C m⁻² yr⁻¹ in 2001. The NEE was significantly influenced by environmental factors. Respiration of the ecosystem, for example, was exponentially dependent on air temperature, while photosynthesis was related to the incident PAR in a manner consistent with the Michaelis–Menten model. Although the vapor pressure deficit (VPD) was scarcely higher than 15 hPa, the CO₂ uptake rate was also depressed when VPD surpassed 10 hPa.     

Gaseous mercury fluxes from the forest floor of the Adirondacks

The flux of gaseous elemental mercury (Hg⁰) from the forest floor of the Adirondack Mountains in New York (USA) was measured numerous times throughout 2005 and 2006 using a polycarbonate dynamic flux chamber (DFC). The Hg flux ranged between −2.5 and 27.2 ng m⁻² h⁻¹ and was positively correlated with temperature and solar radiation. The measured Hg emission flux was highest in spring, and summer, and lowest in winter. During leaf-off periods, the Hg emission flux was highly dependent on solar radiation and less dependent on temperature. During leaf-on periods, the Hg emission flux was fairly constant because the forest canopy was shading the forest floor. Two empirical models were developed to estimate yearly Hg⁰ emissions, one for the leaf-off period and one for the leaf-on period. Using the U.S. EPA's CASTNET meteorological data, the cumulative estimated emission flux was approx. 7.0 μg Hg⁰ m⁻² year⁻¹.