南京市经济发展与环境污染关系的实证研究

根据南京市1991～2003年经济与环境数据，分析经济发展与环境污染的相互关系，建立了南京市经济增长与环境污染水平的计量模型，进而评价了南京市的环境保护政策。研究表明：作为一个重化工业城市，南京市自20世纪90年代以来，在经济高速发展的情况下，其环境恶化程度逐步得到遏制，部分环境指标与人均GDP演替轨迹呈现显著的环境库兹涅茨曲线特征。这主要归功于南京市政府近年来有效的环境政策和巨额的环境投资。     

分洪区洪灾保险工作初探

本文从洪水过程的随机特点及防洪工作的实际需要等各个方面出发,阐述了在分洪区实行洪灾保险的必要性,结合国内外已有的实践经验,分析了这一工作得以顺利开展的可能性。并在此基础上,提出了二种洪灾保险费用计算方法,实例计算结果表明,这些方法是基本可行的。     

狭长地下受限空间火灾分区形成的试验研究

通过狭长地下受限空间的火灾模拟试验,研究O#柴油在不同空间尺度形成的火灾分区现象.分析柴油燃烧时狭长地下受限空间火灾分区现象形成的判断依据、条件、时间,惰化区氧气耗量与空间容积的关系,惰化区氧气体积分数、烟气温度随时间的变化.结果表明.燃料量、空间尺度和燃烧表面积是影响狭长地下受限空间火灾分区形成的主要因素;分区现象形成的判断依据为惰化区氧气体积分数≤16%;分区现象形成的条件为火焰区容积热强度≥720 kW·m-3.这对地下受限空间火灾的防治和其性能化设计具有参考价值.     

Characteristics and recent trends of sulfur dioxide at urban, rural, and background sites in North China: Effectiveness of control measures

SO₂ measurements made in recent years at sites in Beijing and its surrounding areas are performed to study the variations and trends of surface SO₂ at different types of sites in Northern China. The overall average concentrations of SO₂ are (16.8 ± 13.1) ppb, (14.8 ± 9.4) ppb, and (7.5 ± 4.0) ppb at China Meteorological Administration (CMA, Beijing urban area), Gucheng (GCH, relatively polluted rural area, 110 km to the southwest of Beijing urban area), and Shangdianzi (SDZ, clean background area, 100 km to the northeast of Beijing urban area), respectively. The SO₂ levels in winter (heating season) are 4-6 folds higher than those in summer. There are highly significant correlations among the daily means of SO₂ at different sites, indicating regional characteristics of SO₂ pollution. Diurnal patterns of surface SO₂ at all sites have a common feature with a daytime peak, which is probably caused by the downward mixing and/or the advection transport of SO₂-richer air over the North China Plain. The concentrations of SO₂ at CMA and GCH show highly significant downward trends (-4.4 ppb/yr for CMA and -2.4 ppb/yr for GCH), while a less significant trend (-0.3 ppb/yr) is identified in the data from SDZ, reflecting the character of SDZ as a regional atmospheric background site in North China. The SO₂ concentrations of all three sites show a significant decrease from period before to after the control measures for the 2008 Olympic Games, suggesting that the SO₂ pollution control has long-term effectiveness and benefits. In the post-Olympics period, the mean concentrations of SO₂ at CMA, GCH, and SDZ are (14.3 ± 11.0) ppb, (12.1 ± 7.7) ppb, and (7.5 ± 4.0) ppb, respectively, with reductions of 26%, 36%, and 13%, respectively, compared to the levels before. Detailed analysis shows that the differences of temperature, relative humidity, wind speed, and wind direction were not the dominant factors for the significant differences of SO₂ between the pre-Olympics and post-Olympics periods. By extracting the data being more representative of local or regional characteristics, a reduction of up to 40% for SO₂ in polluted areas and a reduction of 20% for regional SO₂ are obtained for the effect of control measures implemented for the Olympic Games.     

Sewage sludge disintegration by high-pressure homogenization: A sludge disintegration model

High-pressure homogenization (HPH) technology was applied as a pretreatment to disintegrate sewage sludge. The effects of homogenization pressure, homogenization cycle number, and total solid content on sludge disintegration were investigated. The sludge disintegration degree (DDCOD), protein concentration, and polysaccharide concentration increased with the increase of homogenization pressure and homogenization cycle number, and decreased with the increase of sludge total solid (TS) content. The maximum DDCOD of 43.94% was achieved at 80 MPa with four homogenization cycles for a 9.58 g/L TS sludge sample. A HPH sludge disintegration model of DD_COD= kN^aP^b was established by multivariable linear regression to quantify the effects of homogenization parameters. The homogenization cycle exponent a and homogenization pressure exponent b were 0.4763 and 0.7324 respectively, showing that the effect of homogenization pressure (P) was more significant than that of homogenization cycle number (N). The value of the rate constant k decreased with the increase of sludge total solid content. The specific energy consumption increased with the increment of sludge disintegration efficiency. Lower specific energy consumption was required for higher total solid content sludge.     

Theoretical study on the reaction mechanism of ozone addition to the double bonds of keto-limonene

The reaction mechanism of ozone (O₃) addition to the double bonds of gas phase keto-limonene was investigated using ab initio methods. Two different possibilities for O₃ addition to the double bond were considered and two corresponding van derWaals complexes (Complex 1 and Complex 2) were found for 1-endo and 2-endo. The rate constants were calculated using the transition state theory at the CCSD(T)/6-31G(d) + CF//B3LYP/6-31G(d,p) level. The high-pressure limit of the total rate constant at 298 K was 3.51 × 10^-16 cm³/(molecule sec), which was in a good agreement with the experimental data.     

Degradation of polycyclic aromatic hydrocarbons by Pseudomonas sp. JM2 isolated from active sewage sludge of chemical plant

It is important to screen strains that can decompose polycyclic aromatic hydrocarbons (PAHs) completely and rapidly with good adaptability for bioremediation in a local area. A bacterial strain JM2, which uses phenanthrene as its sole carbon source, was isolated from the active sewage sludge from a chemical plant in Jilin, China and identified as Pseudomonas based on 16S rDNA gene sequence analysis. Although the optimal growth conditions were determined to be pH 6.0 and 37℃, JM2 showed a broad pH and temperature profile. At pH 4.5 and 9.3, JM2 could degrade more than 40% of fluorene and phenanthrene (50 mg/L each) within 4 days. In addition, when the temperature was as low as 4℃, JM2 could degrade up to 24% fluorene and 12% phenanthrene. This showed the potential for JM2 to be applied in bioremediation over winter or in cold regions. Moreover, a nutrient augmentation study showed that adding formate into media could promote PAH degradation, while the supplement of salicylate had an inhibitive effect. Furthermore, in a metabolic pathway study, salicylate, phthalic acid, and 9-fluorenone were detected during the degradation of fluorene or phenanthrene. In conclusion, Pseudomonas sp. JM2 is a high performance strain in the degradation of fluorene and phenanthrene under extreme pH and temperature conditions. It might be useful in the bioremediation of PAHs.     

极端嗜盐菌Halomonas elogata的分离鉴定及其降解偶氮染料活性兰BRF的条件优化研究

从新疆地区土壤中经驯化、分离纯化得到一株极端嗜盐菌,并对其形态特征、生理生化特性及16S rDNA同源性进行了检索比较,鉴定该菌株为伸长盐单胞菌(Halomonas elogata);其次,考察了不同因素对菌株降解偶氮染料--活性兰BRF的影响,比较了不同盐度条件下的降解率,并在30℃、5%盐度生长条件下采用单因素实验考察了该菌接菌量、染料初始浓度、初始pH等因素对活性兰BRF72h降解率的影响,采用正交试验L9(33)获得适宜的降解条件;最后,通过紫外-可见吸收光谱分析了降解产物.结果表明,该菌株耐盐范围为0～32%,最适生长盐度为5%～20%;在盐度为3%～25%条件下该菌株对活性兰BRF的降解率随着盐度的升高先升后降,5%盐度下的降解效果最佳;在30℃、5%盐度下适宜降解条件为:染料浓度100mg·L-1,pH=7,接菌量5%,72h的降解率为88.62%.紫外-可见光谱结果显示,降解产物的光谱与活性兰BRF的明显不同,可见光区的吸收峰消失,正己烷萃取液无紫外吸收,二氯甲烷萃取液出现两个紫外吸收峰,推测为芳胺类及杂环类等极性化合物;质谱分析证实,降解产物合苯甲基二胺、2,6-氨基苯酚等极性化合物.     

北方地区受污染河湖水体潜流湿地净化技术研究与工程应用

结合实验研究和工程应用实践,在湿地填料选择、水力负荷变化、植物特性、结构优化、越冬运行等方面,对我国北方地区潜流人工湿地设计、建设、运行管理中的关键技术问题开展了系统、深入研究.结果表明:石灰石、粗砂等脱氮除磷综合效果较好,且取材方便、价格便宜,应是人工湿地主选填料,钢渣、褐铁矿除磷效果良好、沸石的氨氮吸附能力强,可作为辅助材料;湿地植物对水质净化贡献约为5%～15%,其地上部分的生物量移除贡献不足5%,湿地植物对系统水力负荷维持、冬季保温、生态景观等还具有较大贡献;以植物保温为主,结合冰下取水、水位管理等可实现北方地区潜流湿地冬季正常运行;优化提出了竖向复合流湿地结构,具有节约用地、硝化-反硝化作用效果显著、抗淤堵等特点.研究成果已在工程实践中得到成功应用,对人工湿地在我国北方地区的推广应用具有重要借鉴意义.     

MBR活性污泥培养驯化过程中生物多样性研究

以MBR反应器启动调试阶段的活性污泥为主要研究对象,系统考察了传统活性污泥法(Conventional activated sludge,CAS)污泥接种至MBR反应器内污泥培养驯化过程中生物多样性情况及微生物群落结构的演变规律.同时,在传统污水污泥检测指标的基础上,对各阶段污泥中总细菌基因组DNA进行提取,应用PCR-DGGE分子生物学技术获得了相应的凝胶电泳图谱并进一步分析了菌群间的相似性.结果表明,以CAS污泥为接种污泥在MBR反应器内培养驯化过程中微生物的多样性变化突出,细菌群落结构演替明显,不同阶段菌群间的相似性说明了各阶段菌群的演变关系:污泥培养驯化是一个逐步有序的过程,微生物随反应器内不同时期及环境的变化而调整,逐渐演变成适应MBR工艺的群落结构.