Isolation and characterization of two novel psychrotrophic decabromodiphenyl ether-degrading bacteria from river sediments

Decabromodiphenyl ether (BDE-209) is a brominated flame retardant and a priority contaminant. Currently, little information is available about its significance in the environment, specifically about its susceptibility to aerobic biotransformation at low temperature. In this work, five phylogenetically diverse BDE-209-degrading bacterial strains were isolated from river sediments of northern China. These strains were distributed among four different genera—Acinetobacter, Pseudomonas, Bacillus and Staphylococcus. All five isolates were capable of growing on BDE-209, among which two isolates show better growth. By detailed morphological, physiological, and biochemical characteristics and 16S rDNA sequence analysis, the two strains were identified and named as Staphylococcus haemolyticus LY1 and Bacillus pumilus LY2. The two bacteria can grow in mineral salt medium containing BDE-209 substrate across the temperatures ranging from 2.5 to 35 °C, with an optimum temperature of 25 °C which could be considered as psychrotrophs accordingly. The degradation experiment showed that more than 70.6 and 85.5 % of 0.5 mg/L BDE-209 were degraded and the highest mineralization efficiencies of 29.8 and 39.2 % were achieved for 0.5 mg/L BDE-209 by S. haemolyticus LY1 and B. pumilus LY2, respectively. To the best of our knowledge, this is the first demonstration for the biodegradation of BDE-209 by two psychrotrophic bacteria isolated from environment.     

青藏铁路沿线热喀斯特湖易发程度的区划评价

随着全球气候的持续转暖,青藏铁路沿线热喀斯特湖数量正在逐年增多、面积逐年增大。湖塘的形成虽然具有一定的随机性特点,但其发生的区域性和重复性特点是热喀斯特湖分布与出现的总体规律。在野外系统勘测调查的基础上,依据工程地质类比原则,结合专家打分、层次分析、信息量、统计量等模型方法,对区域内湖塘产生与发展起一定主导作用的历史因素(灾点密度、灾面密度)和基本地质环境因素(冻土类型、年均地温、植被覆盖度、土质类型、地形坡度)基于ArcGIS平台进行综合分析评价,得出楚玛尔河至风火山段青藏铁路沿线热喀斯特湖易发程度的空间分布。结果表明,占研究区总面积47.97%的高易发区占据了湖塘总数量的87.94%、总面积的91.15%,主要分布在楚玛尔河高平原、北麓河盆地和可可西里山间盆地;中易发、低易发、非易发三个区占据了研究区总面积的52.03%,却仅分布了占总数量12.06%、面积8.85%的热喀斯特湖,主要分布于可可西里山区、风火山山区及河谷地区,与2011年9月份野外考察的热喀斯特湖实际的空间分布状况保持了较好的一致性。     

Species- and tissue-specific accumulation of Dechlorane Plus in three terrestrial passerine bird species from the Pearl River Delta, South China

Little data is available on the bioaccumulation of Dechlorane Plus (DP) in terrestrial organisms. Three terrestrial passerine bird species, light-vented bulbul, long-tailed shrike, and oriental magpie-robin, were collected from rural and urban sites in the Pearl River Delta to analyze for the presence of DP and its dechlorinated products in muscle and liver tissues. The relationships between trophic level and concentration and isomeric composition of DP in birds were also investigated based on stable nitrogen isotope analysis. DP levels had a wide range from 3.9 to 930 ng g⁻¹ lipid weight (lw) in muscle and from 7.0 to 1300 ng g⁻¹ lw in liver. Anti-Cl₁₁-DP and syn-Cl₁₁-DP, two dechlorinated products of DP, were also detected in bird samples with concentrations ranged between not detected (nd)-41 and nd-7.6 ng g⁻¹ lw, respectively. DP preferentially accumulated in liver rather than in muscle for all three bird species. Birds had significantly higher concentrations of DP in urban sites than in rural sites (mean, 300 vs 73 ng g⁻¹ lw). The fractions of anti-DP (f_anti) were higher in birds collected in rural sites than in urban sites. Significant positive correlation between DP levels and δ¹⁵N values but significant negative correlation between f_anti and δ¹⁵N values were found for birds in both urban and rural sites, indicating that trophic level of birds play an important role in determining DP level and isomeric profile.     

分散式污水再生水回用工程的经济性分析

分散式污水再生回用工程是为缓解水危机及改善水环境而进行投资建设的准公益性项目,具有较大外部效益。为准确评价该类项目的经济性,把环境会计理论应用到项目的经济评价中,使得项目的经济效益得以体现。通过对西安某高校分散式污水再生回用工程分析,表明对分散式污水再生回用项目进行投资建设不仅可以改善水环境,又可以获得较好的经济效益。随着可持续发展战略及循环理论的深入贯彻,人们对改善环境的支付意愿的提升将进一步提升该类项目的经济性。     

西安市高新技术产业开发区向生态工业园区的转变经验

生态工业园是继经济技术开发区和高新技术开发区后的第三代工业园区,是实施循环经济的三个领域之一。本文介绍了西安市高新技术产业开发区向生态工业园区转变模式与实施步骤,并总结实践经验。     

酸碱联合调节剩余污泥对有机质的释放和脱水性能的影响

为了研究酸碱联合调节剩余污泥水解酸化过程中溶解性蛋白质(SPN)和溶解性碳水化合物(SPS)的释放规律以及对脱水性能的影响,采用3个反应器,其中,1#为先酸(pH 3.0)后碱(pH 10.0)、3#为先碱(pH 10.0)后酸(pH 3.0)的两段控制方式(每段8 d),同时以2#pH不调作为对比实验。结果表明,3个反应器中SPN和SPS的释放情况是调节为碱性>酸性>空白,在相同的控制阶段,SPN的释放量明显高于SPS的释放量;SPN和SPS的最大释放量出现在1#的碱性阶段(后8 d),SPN在碱性阶段的第2天达到最大释放量(883.618 mg/L),SPS在碱性阶段的第8天达到最大释放量(165.922 mg/L)。1#在实验的整个过程中比阻值较低,说明先酸后碱调节方式更利于污泥脱水;在调节为碱性第4天时污泥比阻(SRF)达到最小值(0.342×1013m/kg),处于中难度脱水范围内。与2#相比,3#中的SRF虽稍有改善,但始终处于难脱水范围内。     

基于响应面法的污泥快速固化效能综合影响简

针对现有污泥固化技术存在的固化养护时间长、低温条件下固化效能低等问题。研究提出污泥快速（3 d）固化技术,采用响应曲面分析方法,重点考察了石灰、组分A、硅酸盐水泥、粉煤灰和温度等5因素对固化效能的综合影响,研究结果表明,石灰、组分A、硅酸盐水泥、粉煤灰和养护温度等因素对3 d固化体的无侧限抗压强度和含水率的线性效应显著,石灰和组分A、石灰和养护温度对无侧限抗压强度的交互影响显著,石灰和粉煤灰、组分A和养护温度、硅酸盐水泥和粉煤灰对含水率的交互影响显著;得出了5因素对固化体3 d无侧限抗压强度和含水率影响的定量模型,可对污泥快速固化进行优化和预测;并利用XRD和SED对污泥固化块的化学成分和微观结构进行了分析。     

活性污泥法处理炼油碱渣废水

采用活性污泥法对某炼油厂预处理后的碱渣废水进行了处理。以目标废水为碳源对活性污泥进行了成功驯化,然后用驯化后的活性污泥对炼油碱渣废水进行净化处理,以降低其COD(化学需要氧量)值。实验结果表明,活性污泥生化处理对炼油碱渣废水的COD值具有较高的降低作用。在水力停留时间为24 h的条件下,COD的平均去除率可达76%,容积负荷为0.7 kg COD/(m3·d)左右,运行10 d后,COD总去除率可达74%左右,出水水质达到国家三级排放标准(GB 8978-1996)。     

微波辅助Cu(Ⅱ)-Fenton体系催化氧化处理对硝基苯酚废水

为了拓宽Fenton反应pH范围,提高降解效率、减少药剂用量,向Fenton体系中添加辅助催化剂Cu(Ⅱ),并对微波辅助催化氧化对硝基苯酚(PNP)模拟废水工艺进行了研究。提出微波辐照-放置处理工艺,并与普通全过程微波处理工艺进行了比较。结果表明,该体系处理工艺将Fenton反应最佳pH范围由2.0~3.5拓宽到2.0~5.5;在pH=5.0时,对于100 mg/L的PNP溶液,当[Cu2+]=0.8 mg/L、[Fe2+]=3.0 mg/L、[H2O2]=0.2 g/L,微波功率250 W,辐照2.0 min、放置4.0 min,PNP去除率可达98%以上;辅助催化剂Cu2+的加入增强了氧化效果,同时节约药品20%以上。通过对比实验发现,Cu2+与Fe2+发生了某种作用机制,联合促进了体系中·OH的生成。该反应体系不仅将传统Fenton反应体系狭窄的pH值范围延伸到接近中性的区域5.0~5.5,又可在短时间内使PNP去除率达到98%以上。