TSLCDM长袋低压脉冲布袋除尘器及其应用

为了使电炉烟气治理过程中污染源的排放达到国家排放标准,提出一种TSLCDM长袋低压脉冲除尘器(简称TSLCDM除尘器)。通过对该除尘器结构、除尘原理以及不同工况下除尘效率和过滤阻力的分析,得到该除尘器的除尘效率>99.9%,压力损失<1200 Pa,最终排出的烟气含尘质量浓度约5.54 mg/m3,满足了国家的超低排放要求,以泉州某公司电炉项目除尘系统为研究对象,证明了该新型脉冲布袋除尘器在电炉烟气治理除尘系统的应用效果,具有很好的经济和环境效益。     

Diversity of antibiotic resistance genes and encoding ribosomal protection proteins gene in livestock waste polluted environment

The rapid development and increase of antibiotic resistance are global phenomena resulting from the extensive use of antibiotics in human clinics and animal feeding operations. Antibiotics can promote the occurrence of antibiotic resistance genes (ARGs), which can be transferred horizontally to humans and animals through water and the food chain. In this study, the presence and abundance of ARGs in livestock waste was monitored by quantitative PCR. A diverse set of bacteria and tetracycline resistance genes encoding ribosomal protection proteins (RPPs) from three livestock farms and a river were analyzed through denaturing gradient gel electrophoresis (DGGE). The abundance of sul(I) was 10³ to 10⁵ orders of magnitude higher than that of sul(II). Among 11 tet-ARGs, the most abundant was tet(O). The results regarding bacterial diversity indicated that the presence of antibiotics might have an evident impact on bacterial diversity at every site, particularly at the investigated swine producer. The effect of livestock waste on the bacterial diversity of soil was stronger than that of water. Furthermore, a sequencing analysis showed that tet(M) exhibited two genotypes, while the other RPPs-encoding genes exhibited at least three genotypes. This study showed that various ARGs and RPPs-encoding genes are particularly widespread among livestock.     

Abundance and removal of antibiotic resistance genes (ARGs) in the rearing environments of intensive shrimp aquaculture in South China

Although research regarding antibiotic resistance genes (ARGs) in aquaculture environments has gained increasing scientific interest, further studies are required to understand the abundances and removal mechanisms of ARGs during the entire rearing period of shrimp aquaculture. Thus, in this study, abundances, distributions and removal rates of ARGs in different environmental compartments of intensive shrimp farms in South China were investigated during the entire rearing period. The results indicated that sul1 and cmlA were the predominant ARGs in the water and sediment samples. Additionally, the total abundance of ARGs was higher in shrimp pond water than in the source water and farm effluent. Moreover, sediment samples indicated significantly higher ARG abundances than water samples from the shrimp ponds (P?<?0.05). Environmental factors were found to significantly affect the distribution of ARGs in shrimp rearing environments. Furthermore, stable ponds aided the removal of ARGs from shrimp pond water. This study accounted for temporal variations in ARG abundances as well as removal of ARGs in different environmental compartments during the entire shrimp rearing period. However, additional research is required to optimize the water treatment process for removal of ARGs from the aquaculture.     

基于BP神经网络的矿车运行时矿井摩擦阻力的预测*

为了快速有效地确定矿车等运输设备在巷道内运行时矿井摩擦阻力的变化情况,克服模拟软件计算量和现场实测工作量大的问题,以巷道风流速度、矿车运行速度、阻塞比、矿车长度4个矿车运行时巷道摩擦阻力的影响因素作为切入点,采用动网格技术模拟得到矿车在巷道内运行时有关矿井摩擦阻力的数据,以此为样本构建基于BP神经网络的矿井摩擦阻力预测模型,运用MATLAB软件进行网络训练,并将BP神经网络预测值与FLUENT模拟值进行对比。研究结果表明:BP神经网络结构比较简单,能以较快速度收敛,预测值与模拟值最大误差在7%以内,该神经网络模型用于求解矿车等运输设备在巷道内运行时摩擦阻力的变化情况是可行的。     

超声波联合PAM对污泥脱水性能的影响

以污泥脱水性能与沉降性能为指标,研究了超声波调理联合PAM对污泥脱水性能的影响。实验结果表明,单独使用超声波调理的最佳调理时间为20 s,此时污泥比阻为0.68×109s2/g;采用PAM对污泥进行调理时,在浓度为0.1%,投加量为100 mg/L时污泥比阻最小,为0.32×109s2/g;采用超声波与PAM联合调理时,利用正交试验得到最适合的组合条件为:调理时间20s、PAM投加量100 mg/L、浓度0.15%。     

树木水分胁迫和抗旱性机理研究进展

本文从植物对干旱胁迫的反应和抗旱指标、光合作用和蒸腾作用和水分利用效率等研究途径,以及人工采取的抗旱措施等方面阐述了森林植物的抗旱性机理研究现状,并提出了今后研究的重点方向。     

我国古代排水、排污设施的变化及发展

本文针对当前城镇主要环境问题之一——排水和污水处理问题,介绍了我国古代在城市排水和污水处理设施建设、管理和规划方面的丰富经验和杰出成就,回溯了从原始社会末期,早期城市雏形出现到城市排水、排污设施的发展、完善,使我们得到启迪,以便更好地解决城镇环境问题,做好排水、排污处理工作。     

广东肇庆奥陶系砂泥岩沉积环境的地球化学表征

以砂泥岩样品的常量/微量元素地球化学特征分析为主要手段,探讨广东肇庆地区奥陶纪沉积环境,为尚显薄弱的云开古陆北缘下古生界沉积学研究提供佐证。以"相当B含量"、Ga、K、Rb、V、Sc等元素组分及其比值为判别指标,分析研究区奥陶系碎屑岩沉积的古水体性质和古环境变化。结果表明,奥陶纪早-中期(缩尾岭群沉积期)海水明显淡化、富氧;奥陶纪晚期(三尖群沉积期)以半咸水-正常咸水为主,水体还原性增强。结合地层岩相特征,认为研究区在奥陶纪期间整体为云开古陆东北缘的滨-浅海,早期可能存在受淡水影响的海陆过渡环境,例如三角洲或河口湾,晚期由于海平面上升逐渐成为浅海陆棚。研究结果有助于进一步了解云开古陆周缘奥陶纪沉积演化,并为开展更为详细的沉积学研究提供参考。     

中心城区的生态安全格局构建研究

本文利用景观生态学的理论,采用最小累计阻力模型,评价深圳市福田区的景观生态安全格局.结果表明,福田区当前存在景观格局破碎、生态安全网络不完善、生态廊道孤立和生态流连接性差等问题.对此,本文提出优化生态节点、生态廊道和生态网络等措施,提出"一心、一轴、一环、三带、六区"的福田区生态安全格局规划,以满足城市发展的需要及保护城市生态系统的生态过程和基本服务功能.     

初始pH对厌氧环境下污泥中抗生素抗性基因行为特征的影响

污水处理厂产生大量的剩余污泥中含有丰富的抗性基因,给环境带来了潜在风险。以城市污水处理厂的剩余污泥为研究对象,在不同初始p H(对照组、初始p H=3、5、7、9、11)下观察厌氧条件下,8种抗生素浓度以及四环素类抗性基因(tet A、tet G、tet L、tet M、tet O、tet Q、tet W、tet X)、磺胺类抗性基因(sul I、sul II)和Ⅰ类整合子(int I 1)的行为特征。研究结果显示,初始p H对抗生素的降解影响较小,污泥中总抗生素的平均去除率为42%。对照组及初始p H为3、5、7、9、11下的总四环素类抗性基因分别削减0.65 log、0.96 log、0.75 log、0.62 log、0.86 log和0.98 log。不同四环素类抗性基因表现相似,在初始p H=3和初始p H=11下部分抗性基因削减较多,特别是tet A、tet G、tet L、tet O和tet X。2种磺胺类抗性基因均无削减,浓度平均上升0.18log。相关性分析显示,总抗性基因与TN、NH3-N、TP、SCOD(溶解性COD)均存在显著相关性(P0.05)。上述研究结果为污泥厌氧消化中抗生素抗性基因减量条件提供参考依据。