基于分区曝气工艺的单户型一体化乡村污水处理设备的性能评估

针对我国国情,应用分区曝气的原理开发了一款适用于乡村污水治理的单户型一体化污水处理设备。以常熟市某生活污水处理厂旋流沉砂池的进水为处理对象,对该设备的性能进行研究。结果表明,设备在水力停留时间(HRT)为10 h、曝气量为1.2 m3·h-1、回流比为1∶1时达到最佳工况点,出水COD、NH+4-N及SS达到1级A标准,TN达到1级B标准(GB 18918-2002)。研究发现,非曝气Ⅰ区内的填充介质有助于形成反应器内部的厌氧微环境,从而可以抑制回流液中的溶解氧对该区反硝化反应的不利影响。设备停运后的恢复能力与停运时间及环境温度等因素有关,而分区曝气工艺与固定床技术在设备停运恢复能力较弱时对出水水质有一定的缓冲作用。     

Vegetation phenology gradients along the west and east coasts of Greenland from 2001 to 2015

The objective of this paper is to characterize the spatiotemporal variations of vegetation phenology along latitudinal and altitudinal gradients in Greenland, and to examine local and regional climatic drivers. Time-series from the Moderate Resolution Imaging Spectroradiometer (MODIS) were analyzed to obtain various phenological metrics for the period 2001–2015. MODIS-derived land surface temperatures were corrected for the sampling biases caused by cloud cover. Results indicate significant differences between West and East Greenland, in terms of both observed phenology during the study period, as well as the climatic response. The date of the start of season (SOS) was significantly earlier (24 days), length of season longer (25 days), and time-integrated NDVI higher in West Greenland. The sea ice concentration during May was found to have a significant effect on the date of the SOS only in West Greenland, with the strongest linkage detected in mid-western parts of Greenland.     

低接种污泥量强化循环厌氧反应器(SCAR)处理生活污水

采用强化循环高效厌氧反应器(SCAR)处理生活污水研究反应器的启动过程和运行特性。在低接种污泥量、回流比R=0.5、HRT为16 h条件下经过65 d完成反应器启动,系统出水COD稳定在约80 mg·L^-1,VFA浓度约240 mg·L^-1,颗粒污泥性状良好,微生物活性增强。SCAR反应器对污染物的去除受水力停留时间和反应器外回流比影响,微生物生化反应时间和在反应器中的空间分布状态共同决定着反应器的运行效果。SCAR反应器脱氮作用明显,实验条件下反应器对总氮的去除主要是通过反硝化作用实现。     

荧光光谱与OUR联用表征内源呼吸过程

采用荧光光谱与耗氧速率（OUR）相结合的方法,探究了内源呼吸过程中微生物代谢状态变化的典型特征。结果表明,OUR变化率曲线中的拐点可以将内源呼吸划分为3个阶段。通过荧光光谱监测发现,在2~4 d时胞外聚合物（EPS）出现了突然增多的现象,疏松结合的胞外聚合物（LB-EPS）中峰A（Ex/Em=230 nm/（334~338）nm）、峰B（Ex/Em=（280~285）nm/（334~344）nm）的荧光强度分别升高了447%、128%,紧密结合的胞外聚合物（TB-EPS）中峰A、峰B的荧光强度分别升高了471%和128%,且COD的去除率在第4天达到最大为91.7%,表明位于此区域的微生物活性高、代谢状态好且污染物去除率高。LB-EPS和TB-EPS的荧光特性及OUR变化率可以指示内源呼吸3个不同阶段的变化,但TB-EPS对内源呼吸过程的划分更为准确,而OUR变化率在实际操作中更具有意义。     

铁镍改性膨润土对废水中有机污染物的吸附性能研究

以钠基膨润土为原料,制备了铁镍无机改性土和铁镍有机复合改性土,并应用于造纸废水的处理,探讨了改性土用量、废水pH值、搅拌时间等因素对COD去除率的影响,通过正交实验对实验条件进行了优化.结果表明：铁镍有机复合改性土和铁镍元机改性土对废水的处理效果明显好于原土;膨润土的用量、废水的pH对COD的去除率影响较大;对于铁镍无机改性土,吸附剂用量为12g/L,溶液pH=2,吸附时间为10 min时,对废水中COD的去除率为54.06%;对于铁镍有机复合改性土,吸附剂用量为14g/L,溶液pH=3,吸附时间为20 min时,对废水中COD的去除率为70.10%.     

纤维素废弃物水热处理制H2的研究进展

水热处理为纤维素废弃物资源化应用开辟了一条新的途径，文中就水热处理技术的特点、水热条件下纤维素的降解过程进行了介绍，并着重综述了纤维素废弃物水热制H2方面的研究进展，同时对纤维素及其废弃物的水热处理和资源化研究前景进行了展望。     

Sequential UV-biological degradation of chlorophenols

The sequential UV-biological degradation of a mixture of 4-chlorophenol (CP), 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP) was first tested with each pollutant supplied at an initial concentration of 50 mg l(-1). Under these conditions, the chlorophenols were photodegraded in the following order of removal rate: PCP>TCP>DCP>CP with only CP and DCP remaining after 40 h of irradiation. The remaining CP (41 mg l(-1)) and DCP (13 mg l(-1)) were then completely removed by biological treatment with an activated sludge mixed culture. Biodegradation did not occur in similar tests conducted with a non-irradiated mixture due to the high microbial toxicity of the solution. UV treatment lead to a significant reduction of the phytotoxicity to Lipedium sativum but no further reduction of phytotoxicity was observed after biological treatment. Evidence was found that the pollutants were partially photodegraded into toxic and non-biodegradable products. When the pollutants were tested individually (initial concentration of 50 mg l(-1)), PCP, TCP, DCP, 4-CP were photodegraded according to first order kinetic model (r2>99) with half-lives of 2.2, 3.3, 5.7, and 54 h, respectively. The photoproducts were subsequently biodegraded. This study illustrates the potential of UV as pre-treatment for biological treatment in order to remove toxicity and enhance the biodegradability of organic contaminants. However, it also shows that UV treatment must be carefully optimized to avoid the formation of toxic and/or recalcitrant photoproducts and results from studies conducted on single contaminants cannot be extrapolated to mixtures.     

负载型磷酸氧钒低温脱硝催化剂的制备及其抗硫抗水性能

针对目前低温脱硝催化剂抗硫抗水性较差的不足,以TiO2为载体负载活性组分V2O5,利用磷酸调控表面酸性,制备了磷酸氧钒催化剂VPO/TiO2,并实验研究了SO2和水蒸气对其脱硝活性的影响。结果表明：控制P与V的摩尔比为1/5,活性组分(VPO)负载量为10%,焙烧温度为400 ℃时,催化剂脱硝性能最好,180~400 ℃温度范围内脱硝率高于98%;反应温度为200 ℃,烟气中SO2体积分数为200×10-6~800×10-6和水蒸气体积分数为4%时,催化剂的活性无明显下降。添加磷酸能够促使催化剂表面生成VOPO4、(VO)2P2O7及V4+/V5+氧化还原电对,提高了催化剂的低温脱硝活性。磷酸可增强催化剂的表面酸性,减少了SO2的表面吸附及其与活性组分的反应。另外,催化剂表面以介孔为主,可提高未被水分子占据的活性位点量,FT-IR图谱显示抗硫抗水测试后的VPO/TiO2表面未发现有硫酸根生成,VPO/TiO2表现出较强的抗SO2和水蒸气毒化的性能。负载型磷酸氧钒催化剂具有较高的脱硝活性和较强的抗硫抗水性能。     

Analysis of halogenated polycyclic aromatic hydrocarbons in urban air, snow and automobile exhaust

Urban air, snow and automobile exhaust samples were extensively cleaned up by open column liquid chromatography. The appropriate fractions were analysed for halogenated polycyclic aromatic hydrocarbons (XPAH) by gas chromatography/negative chemical ionization mass spectrometry (GC/NCIMS). XPAH were found in all three sample types. A urban air sample was found to contain chlorinated pyrenes, fluoranthenes and benzopyrene and brominated pyrenes and fluoranthenes. Furthermore, the concentration of 1-chloropyrene in that air sample was estimated to be 10 pg/m³. XPAH were also found in snow samples taken in the vicinity of a motor-way. Ethylene dibromide and ethylene dichloride, are probably the source of the halogen atoms in the XPAH detected in car exhaust.     

乙二胺还原的氧化石墨烯对镉离子的动态吸附

以乙二胺(EDA)还原氧化石墨烯(GO)制得一种吸附剂材料,即还原态氧化石墨烯(RGO)。考察了动态条件下Cd2+溶液的初始浓度、流速及吸附床高度对穿透曲线的影响,同时利用Bed-Depth-Service Time(BDST)模型对吸附床高度与穿透时间的关系进行线性拟合分析,研究了RGO对Cd2+溶液的动态吸附性能。结果表明,RGO可以有效地去除水溶液中的Cd2+,随着吸附床高度的增加,离子的去除率增大,穿透时间延长;当溶液初始浓度增大时穿透时间缩短,离子的去除率减小;而溶液的流速加快,穿透时间和去除率都相应减小。吸附床高度与穿透时间的关系可用BDST模型较好地进行描述,预测新的操作条件下的穿透时间与实验值误差均小于5%。