加油站地下储油罐压力管理系统的相关研究

在当前普遍采用的加油站真空辅助式第二阶段油气回收系统中,为了避免回收到地下储油罐中的油气再次通过P/V阀排空,必须对其中气相空间的压力实施有效控制。从国外的发展情况来看,地下储油罐的压力管理系统主要分为基于膜分离技术、基于弹性气囊和基于活性炭吸附三大类,其中膜法油气回收装置在国内已经得到了较多关注。首次系统介绍了气囊式压力管理系统的工作原理及其主要结构设计,具体包括管线布局、钢制压力容器壳体、位于容器顶部封头上的接口组件和全部位于容器内的气囊等;同时对另外一种可行方案进行了分析。     

C/N比和曝气量影响MBR同步硝化反硝化的研究

通过连续运行MBR研究了C/N比和曝气量对同步硝化反硝化的影响,结果表明,在环境温度13～23℃,MLSS为6.0～6.8 g/L,进水NH⁺₄-N浓度50 mg/L,曝气量0.5 m³/h,HRT为6 h实验条件下,总氮去除率随着进水C/N比的增加而增加,在C/N比为6∶1～8∶1时,TN去除率达到79%～89%,低的C/N比抑制反硝化,过高的C/N比增加了碳源补加的成本。改变反应曝气量,当C/N比为6∶1,曝气量为0.4 m³/h时,TN的去除率达到了最大值85%。曝气量过高或过低,TN去除率均下降。并对在不同曝气量下MBR 内的DO 值分布进行了初步研究。     

膜生物反应器处理微污染水源水的研究与应用现状

膜生物反应器及其组合工艺能实现水源水中微污染物的有效去除,是一种新型高效水处理工艺.总结了膜生物反应器处理微污染水源水的研究与应用现状、污染物去除效果和机制;在分析膜污染机制基础上归纳了膜污染控制和污染膜清洗方式,展望了膜生物反应器在给水领域应用需克服解决的技术难点.     

The sedimentation capabilities of hexadecyltrimethylammonium-modified montmorillonites

Natural montmorillonite was modified with a quaternary ammonium compound, hexadecyltrimethylammonium (HDTMA). The sedimentation capabilities of unmodified and modified montmorillonites were then investigated. The sedimentation velocity of modified montmorillonites increased if the amounts of adsorbed HDTMA were from 0.3 to 1.0 times the cation exchange capacitity (CEC). It also emerged that the sedimentation capability of modified montmorillonites was improved and that the variously CEC-modified montmorillonites had similar sedimentation capabilities after they had sorbed organic matter from oily wastewater. Thus, modified montmorillonites (especially 0.5 CEC treatment) had good sedimentation capabilities for sorbing organic substance and can act as carriers in wastewater biotreatment.     

SBR降解动力学研究

采用SBR工艺处理有机废水,在已有工艺条件下对生物降解动力学进行了研究,得出生物降解反应为一级反应。研究表明,用Monod公式能较好反映出有机物的降解规律,确定了其动力学参数V_max=14.6306 d^-1,K_s=83.2993 mg/L,得出SBR降解动力学模型为V=14.6306X·S/(83.2993+S)。利用以动力学为基础的动态模拟法优化SBR工艺,实验结果表明该方法合理可行,对SBR的设计与运行有一定的指导作用,可作为SBR反应器扩大实验和设计的依据。     

土壤重金属的植物污染化学研究进展

针对中国土壤重金属污染加剧的趋势,为改善土壤环境质量和保障农产品安全,提出了土壤重金属的植物污染化学研究领域.结合多年的研究工作,从土壤重金属的植物根际化学行为、土壤重金属的植物吸收与解毒机制和重金属污染土壤的植物-微生物交互作用等方面简要阐述了土壤-植物系统中重金属的分布、存在形态、迁移转化、累积及生物学效应和控制规律的研究进展,并对将来的植物污染化学理论研究提出了展望.     

人工浮床栽培7种植物在富营养化水体中的生长特性研究

本研究利用人工浮床在富营养化水体栽培了7种植物,成活率都在70%以上,2个月的生长期内生物的生长量都超过20kg鲜重/m2.浮床栽培芦苇的净化效果最好,每平方米的芦苇浮床可以使117.93 m3的水从V类水质净化为Ⅲ类水质(以总磷计),其次分别为荻、水稻、蕹菜、牛筋草、香蒲和美人蕉.对蕹菜和水稻植株的检测表明,分别作为蔬菜和青饲料完全符合国家有关卫生标准.     

Pollution characteristics of 23 veterinary antibiotics in livestock manure and manure-amended soils in Jiangsu province,China

The aim of this study was to investigate the pollution characteristics of typical veterinary antibiotics in manure and soil of livestock farms in Jiangsu province. This investigation employed solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A total of 53 manure and 50 amended soil samples from 16 livestock farms in Jiangsu province were collected for analysis. In the manure samples, the highest detected frequencies and concentrations were those of tetracyclines (TCs, 54.1 ± 5775.6 μgkg^?1), followed by fluoroquinolones (FQs, 8.4 ± 435.6 μgkg^?1), sulphonamides (SAs, 3.2 ± 5.2 μgkg^?1) and macrolides (MACs, 0.4 ± 110.5 μgkg^?1). Statistical analysis was used to illuminate the pollution characteristics of 23 veterinary antibiotics for various animal types and different regions in Jiangsu province. The results showed that the pollution level in cow manure was relatively lower compared with pig and chicken manure due to the relative restriction of medication. Furthermore, contamination was serious in amended soil from chicken farms. The pollution level in manure among different regions was higher to the south and north compared with the centre of the region. The same outcome was found for soil. Antibiotic residues in organic fertilizer were also investigated in this study. We found that although the detected concentration was lower in organic fertilizer than in fresh manure, detection frequencies (10–90%) were high, especially for roxithromycin (90%) in MACs (30–90%). This finding suggests attention should be paid to the pollution levels in organic fertilizer. This study is the first extensive investigation of the occurrence and distribution of many kinds of typical veterinary antibiotics in manure and soil from livestock farms of Jiangsu province. This investigation systematically assesses veterinary antibiotics usage and related emissions in southeast China.     

Variations of metal distribution in sewage sludge composting

In the study, the variations of heavy metal distributions (of Cu, Mn, Pb, and Zn) during the sewage sludge composting process were investigated by sequential extraction procedures. The total content of Cu and Zn in the composted mixture increased after the composting process. Mn and Zn were mainly found in mobile fractions (exchangeable fraction (F1), carbonate fraction (F2), and Fe/Mn oxide fraction (F3)). Cu and Pb were strongly associated with the stable fractions (organic matter/sulfides fraction (F4) and residual fraction (F5)). These five metal fractions were used to calculate the metal mobility (bioavailability) in the sewage sludge and composted mixture. The mobility (bioavailability) of Mn, Pb, and Zn (but not Cu) increased during the composting process. The metal mobility in the composted mixture ranked in the following order: Mn>Zn>Pb>Cu.     

Influence of clay minerals on the reduction of Cr6+ by citric acid

The influence of clay minerals on the reduction of Cr6+ by citric acid was investigated at pH values 4.0, 4.5 and 5.0 at 25 degrees C. The results indicate that montmorillonite and illite greatly accelerate the reduction reactions at pH 4.0 and 4.5, but their effects are dramatically reduced at pH 5.0. The role of clay minerals in accelerating the reactions is in the order: illite>montmorillonite>kaolinite, which has a positive correlation with the amount of Mn2+ adsorbed on the surfaces of these minerals. With light, Fe(3+) also significantly increases reaction rates. Ethylenediaminetetraacetic acid (EDTA) greatly suppresses the acceleration of the reduction reactions by these minerals, indicating that EDTA competes with citric acid for Mn2+. Thus, the formation of complexes between Mn(2+) and citric acid could be a prerequisite for the acceleration of the reductions of Cr6+ by clay minerals. In addition, there is no relationship between the specific surface area of clay minerals and the reduction rate of Cr6+ by citric acid.