Investigation of the accumulation of ash,heavy metals,and polycyclic aromatic hydrocarbons to assess the stability of lysis–cryptic growth sludge reduction in sequencing batch reactor

The accumulation of ash, heavy metals, and polycyclic aromatic hydrocarbons (collectively called potential accumulating substances, PAS) was evaluated to ascertain the stability of lysis–cryptic growth sludge reduction process (LSRP) for municipal sludge treatment. One sequencing batch reactor (SBR) incorporated with homogenization was run to test the LSRP and another SBR as a control. The continuous monitoring results for 2 months showed that the ash and heavy metals slightly increased, and the polycyclic aromatic hydrocarbons decreased by 18.0%, indicating that there may be negligible accumulations during the LSRP. Their accumulations met pattern I, as demonstrated by statistical analysis, proving no PAS accumulation for LSRP. This was further confirmed by sludge activity and system performance. Moreover, the mechanism for no PAS accumulation was discussed. It was concluded that the LSRP was stable with no worries about PAS accumulation under the operational conditions.     

Lead,zinc and copper accumulation and tolerance in populations of Paspalum distichum and Cynodon dactylon

Both Fankou and Lechang lead/zinc (Pb/Zn) mine tailings located at Guangdong Province contained high levels of total and DTPA-extractable Pb, Zn and Cu. Paspalum distichum and Cynodon dactylon were dominant species colonized naturally on the tailings. Lead, zinc and copper accumulation and tolerance of different populations of the two grasses growing on the tailings were investigated. Tillers of these populations including those from an uncontaminated area were subjected to the following concentrations: 5, 10, 20, 30 and 40 mg l(-1) Pb, 2.5, 5, 10, 20 and 30 mg (l-1) Zn, or 0.25, 0.50, 1 and 2 mg l(-1) Cu for 14 days, respectively, then tolerance index (TI) and EC50 (the concentrations of metals in solutions which reduce 50% of normal root growth) were calculated. The results indicated that both Lechang and Fankou populations of the two grasses showed a greater tolerance to the three metals than those growing on the uncontaminated area, which suggested that co-tolerant ecotypes have evolved in the two grasses. P. distichum collected from Fankou tailings had the highest tolerance to Cu while Lechang population the highest tolerance to Pb and Zn among the tested populations, and tolerance levels in P. distichum were related to metal concentrations in the plants. P. distichum had a better growth performance than C. dactylon when both of them were grown on the tailings sites. Tolerant populations of these species would serve as potential candidates for re-vegetation of wastelands contaminated with Pb, Zn and Cu.     

微生物法和微生物生态法的评价和选用

微生物法和微生物生态法作为生物治理方案的两大类型，已日益受到环保工作者的重视。这两种类型的治理方法各有特点，各有利弊。如何选择使用？主要取决于污染场所中污染形成的时间长短、污染程度、污染物浓度、污染物中是否含有污水、是否需要快速治理等。应明确指出的是，采用生物治理法虽可在多种情况下大大降低污染物的浓度，但从长远来看，还不能单纯依靠降低污染物的排放浓度，而是应从低浓度污染物对人和环境产生的长期影响着眼，制定出一套治理标准，这样才能准确评价生物治理技术在环境保护中所起的真正作用。     

负载型Mn-Co/TiO2催化剂的制备及其低温NH3选择催化还原NO

采用浸渍法制备了一系列以成型TiO2为载体的Mn-Co/TiO2低温SCR催化剂,研究分析了活性组分担载量、Mn含量、焙烧温度、焙烧时间等制备参数和进口NO浓度、空速、O2体积分数、NH3/N2摩尔比等操作条件对催化剂脱硝反应活性的影响.结果表明:活性组分担载量为30%,Mn/(Mn+Co)摩尔比为80%,在500℃下焙烧6 h得到的Mn-Co/TiO2催化剂具有较高的NO转化率;在进口NO浓度为600×10-6、O2体积分数6%、空速10000 h-1、150℃条件下,NO脱除率接近100%.     

兰州市大气颗粒物多环芳烃的恒能量同步荧光光谱特征研究

通过传统单波长激发/发射荧光光谱法与恒能量同步荧光光谱法进行对比,对大气颗粒物中多环芳烃(PAHs)进行了定性定量分析,采用恒能量同步荧光光谱法在不同能量差下建立了15种典型PAHs成分的恒能量同步荧光法的标准谱库.在各PAHs在最佳能量差下进行定量分析,结果表明,除苊荧光信号响应较差外,其余PAHs的LOD和LOQ分别为0.0580～3.18、0.232～12.7 ng·mL~(-1).15种PAHs的空白和一定浓度下的加标回收率范围在82.8%～120.0%,相对标准偏差范围在0.51%～5.87%之间,以恒能量同步荧光光谱进行了兰州地区大气颗粒物中15种PAHs分布特征分析.     

线板排布对静电除尘性能影响的数值模拟

为揭示电极排布对线板式电除尘器除尘性能的影响规律,基于电晕电场模型、k-ε湍流模型、Lawless电荷累积模型,建立了电除尘多物理场模拟模型,并通过改变极板间距和极线间距,分析了电场电势、风速、颗粒运动轨迹、除尘效率的变化特征。结果表明：极板间距增大降低了电势变化速率,极线间距减小导致放电极电势分布由点式转为条状,极线周围电势影响程度增强;增加极板间距或极线间距,均能减小流场内涡流范围,提高流速分布的均匀性;极板间距或极线间距减小,颗粒轨迹偏移的角度增大,除尘效率随之升高,且颗粒在电场停留的时间缩短;除尘效率与颗粒粒径呈正相关,除尘效率与极板间距或极线间距呈负相关。模拟得到的优化工况为：当极线间距为180 mm、极板间距为200 mm时,电除尘器对粒径为2.5 μm的颗粒除尘效率为98.6%。本研究通过构建新的模拟模型应用于线板式电除尘器的工况优化中,可为电除尘器结构优化设计和性能提升提供参考。     

臭氧预处理制备PVDF接枝SSS离子交换膜

为了降低离子交换膜的制膜费用,同时为后期微生物燃料电池中的应用提供依据和参考,实验研究了用臭氧预处理过氧化苯甲酰（BPO）引发条件制备聚偏氟乙烯（PVDF）接枝对苯乙烯磺酸钠（SSS）聚合物（PVDF-g-SSS）。傅里叶红外分光光度计（FT-IR）确认了产物的化学组成,用溶剂挥发法制得离子交换膜（PS膜）。通过X射线衍射仪（XRD）和X射线光电子能谱仪（XPS）分析了膜的结晶形态及膜面元素组成,并考察SSS单体用量对膜的离子交换容量、电导率及亲水性等性质的影响。结果表明：接枝反应对PVDF晶型影响较小,PS膜表面有S元素生成;臭氧处理后PVDF易与SSS发生接枝聚合反应,且离子交换容量与SSS单体用量成较好的线性关系,当PVDF/SSS的配比为1：5,PVDF-g-SSS占铸膜液含量的5%时,PS膜的最高离子交换容量可达2.5 mmol·g-1,电导率可达0.046 s·cm-1。     

铁盐与铝盐对腈纶废水生化出水混凝特性的对比

针对腈纶废水生化单元出水,对比研究了Al2(SO4)3和Fe2(SO4)3在不同絮凝剂投量和pH时的混凝处理效果,并利用紫外-可见分光光度法(UV-Vis)、三维荧光光谱(EEM)、凝胶渗透色谱(HPSEC)等对混凝特性进行了初步探讨。研究显示,2种混凝剂在投量为63.5 mg/L时可获得30%以上的COD去除率,且最佳pH为中性附近。当投量小于32 mg/L时,Al2(SO4)3较Fe2(SO4)3具有更高的COD去除率,进一步增大混凝剂的投量很难提高Al2(SO4)3对COD的去除率,而Fe2(SO4)3则在有限范围内能持续提高COD去除率。EEM光谱分析显示,与Al2(SO4)3相比,Fe2(SO4)3对有机物具有更广的处理范围和更好的去除效果。HPSEC分析表明,Fe2(SO4)3相对于Al2(SO4)3在去除重均分子量为2 776、1 856和1 325 Da的有机物组分方面具有优势。铁盐或铝盐混凝是深度净化腈纶废水生化单元出水的可行方案之一。     

根表铁膜对凤眼莲吸收环丙沙星的影响

为探讨铁离子不同浓度处理下水生植物根表铁膜形成及其对环丙沙星(ciprofloxacin,CIP)吸收的影响,采用室内模拟试验,分析0.1 mg·L-1 CIP胁迫下不同浓度铁离子(0、10、20、50、100和150 mg·L-1)对凤眼莲根系生理生化及CIP富集量的影响.结果 表明,不同浓度铁离子对凤眼莲根系孔隙度...     

建筑小区雨水径流的土壤渗透净化

讨论了建筑小区雨水径流的污染性、土壤渗透对小区径流的净化作用及土壤的渗透能力，提出了建筑小区雨水径流土壤渗透的工程实施方案。