Distinct community assembly processes underlie significant spatiotemporal dynamics of abundant and rare bacterioplankton in the Yangtze River

• Season and landform influenced spatiotemporal patterns of abundant and rare taxa. • Different stochastic processes dominated abundant and rare subcommunity assembly. • River flow and suspended solids regulated assembly processes of rare taxa. The rare microbial biosphere provides broad ecological services and resilience to various ecosystems. Nevertheless, the biogeographical patterns and assembly processes of rare bacterioplankton communities in large rivers remain uncertain. In this study, we investigated the biogeography and community assembly processes of abundant and rare bacterioplankton taxa in the Yangtze River (China) covering a distance of 4300 km. The results revealed similar spatiotemporal patterns of abundant taxa (AT) and rare taxa (RT) at both taxonomic and phylogenetic levels, and analysis of similarities revealed that RT was significantly influenced by season and landform than AT. Furthermore, RT correlated with more environmental factors than AT, whereas environmental and spatial factors explained a lower proportion of community shifts in RT than in AT. The steeper distance–decay slopes in AT indicated higher spatial turnover rates of abundant subcommunities than rare subcommunities. The null model revealed that both AT and RT were mainly governed by stochastic processes. However, dispersal limitation primarily governed the AT, whereas the undominated process accounted for a higher fraction of stochastic processes in RT. River flow and suspended solids mediated the balance between the stochastic and deterministic processes in RT. The spatiotemporal dynamics and assembly processes of total taxa were more similar as AT than RT. This study provides new insights into both significant spatiotemporal dynamics and inconsistent assembly processes of AT and RT in large rivers.     

高浓度难降解乳化废水湿式氧化动力学

以高浓度难降解乳化废水为处理对象,在2L高压间歇反应釜中,研究了温度对湿式氧化的影响和动力学特征。结果表明,升高温度不但促使反应向直接氧化成终产物方向偏移,也使中间产物加速氧化,使CODcr和TOC去除率显著提高,220℃时可分别达86．4％和79．5％;通用动力学模型能较好预测湿式氧化过程,并得到基于CODcr的表观活化能：有机物直接氧化成终产物为6．19kJ／mol;中间产物氧化成终产物为24．47kJ／mol。     

Occurrence and distribution of antibiotics in coastal water of the Bohai Bay, China: impacts of river discharge and aquaculture activities

The presence of 21 antibiotics in six different groups was investigated in coastal water of the Bohai Bay. Meantime, to illuminate the potential effects caused by the river discharge and aquaculture activities, wastewater from three breeding plants and surface water from six rivers flowing into the Bohai Bay were also analyzed for the selected antibiotics. The result revealed that measured antibiotics in the North Bobai Bay were generally higher than those in the South, highlighting the remarkable effects of high density of human activities on the exposure of antibiotics in environment. The antibiotics found in the six rivers were generally higher than those in the Bohai Bay reflecting the important antibiotics source of river discharge. This study reveals that the high consumption of some antibiotics in aquaculture activities may pose high ecological risk to the bay.     

3种草皮缓冲带对农田径流污染物的净化效果及其最佳宽度研究

通过对照试验,研究了百慕大、白花三叶草和高羊茅3种草皮缓冲带对农田径流污染物的净化效果.结果表明,空白对照带对径流水SS几乎没有去除效果,百慕大草皮缓冲带对径流水SS的去除率最高,达84%.其次为白花三叶草和高羊茅草皮缓冲带,对径流水SS的去除率分别为81%、73%;进水TN质量浓度在10 mg/L以内时,3种草皮缓冲带出水TN质量浓度都低于2mg/L,均达到<地表水环境质量标准>(GB 3838-2002)V类标准;进水TP质量浓度为0.54～1.50 mg/L时,3种草皮缓冲带出水TP质量浓度均为0.08～0.34 mg/L,也均低于GB 3838-2002V类标准规定的限值;3种草皮缓冲带径流水SS去除率和沿程距离具有显著的相关性,在径流水SS去除率为80%时.通过计算可知3种草皮缓冲带的最佳宽度为16.1～20.4 m.其中百慕大草皮缓冲带最低,为16.1 m.     

Fe/TiO2光催化降解水溶液中的4-氯苯酚

以TiO2-P25及FeC2O4为前驱物制备了Fe3 掺杂TiO2光催化剂--Fe/TiO2.X射线衍射结果表明,500 ℃煅烧温度下的Fe/TiO2主要是锐态矿晶型,当掺Fe3 量为0.5%(质量分数,下同)时,Fe3 以取代掺杂形式进入TiO2晶格,而当掺Fe3 量达5.0%时,则出现α-Fe2O3的特征衍射峰;900 ℃煅烧温度下的Fe/TiO2则均为金红石晶型,掺Fe3 量达2.0%～5.0%时,出现Fe2TiO5的特征衍射峰.4-氯苯酚的光催化实验结果表明,煅烧温度及Fe3 掺杂量对Fe/TiO2的光催化活性有显著影响,以煅烧温度500 ℃及掺Fe3 量0.5%的Fe/TiO2为光催化剂,反应80 min,4-氯苯酚的降解率达100%,总有机碳去除率约95%.     

浙江地质灾害发育类型和分布特征

从地形地貌、地质构造、岩土结构、水文气候及人类活动等方面简述了浙江地质灾害的发生背景,并进一步论述了浙江地质灾害的发育类型及时空分布特征。     

高放废物处置库中缓冲/回填材料膨胀特性研究进展

根据近年来国内外学者的研究成果,重点从缓冲/回填材料膨胀性试验方法、影响膨胀性的主要因素和膨胀机理等方面总结了该课题的研究现状及进展,得到如下认识:(1)在试验方法方面,根据加载条件可将膨胀率试验分为有荷和无荷两种形式,而膨胀力试验方法主要有三种,不同试验方法获得的膨胀力存在差别;(2)三向膨胀试验为研究缓冲/回填材料膨胀性各向异性提供了可行的途径,柔性边界试验可模拟更真实的膨胀环境;(3)影响缓冲/回填材料膨胀特性的主要因素包括矿物成分、孔隙溶液性质、干密度、初始含水率和添加剂性质等;(4)针对膨润土/添加剂混合物的膨胀性,学界基于膨润土含量、密度、孔隙比等参数提出了多种预测模型;(5)缓冲/回填材料的干密度和试样尺寸会影响其收缩特性。针对目前该课题的研究现状和不足,提出了今后的研究重点和方向,主要包括复杂耦合条件下的膨胀特性、三向膨胀试验与多边界条件试验、具体应用研究、收缩特性研究、添加剂与膨润土相互作用机制、大尺度长期室内模型试验和原位试验等。     

Performance and microbial community analysis of bioaugmented activated sludge for nitrogen-containing organic pollutants removal

Nitrogen-containing organic pollutants (quinoline, pyridine and indole) are widely distributed in coking wastewater, and bioaugmentation with specific microorganisms may enhance the removal of these recalcitrant pollutants. The bioaugmented system (group B) was constructed through inoculation of two aromatics-degrading bacteria, Comamonas sp. Z1 (quinoline degrader) and Acinetobacter sp. JW (indole degrader), into the activated sludge for treatment of quinoline, indole and pyridine, and the non-bioaugmented activated sludge was used as the control (group C). Both groups maintained high efficiencies (> 94%) for removal of nitrogen-containing organic pollutants and chemical oxygen demand (COD) during the long-term operation, and group B was highly effective at the starting period and the operation stage fed with raw wastewater. High-throughput sequencing analysis indicated that nitrogen-containing organic pollutants could shape the microbial community structure, and communities of bioaugmented group B were clearly separated from those of non-bioaugmented group C as observed in non-metric multidimensional scaling (NMDS) plot. Although the inoculants did not remain their dominance in group B, bioaugmentation could induce the formation of effective microbial community, and the indigenous microbes might play the key role in removal of nitrogen-containing organic pollutants, including Dokdonella, Comamonas and Pseudoxanthomonas. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis suggested that bioaugmentation could facilitate the enrichment of functional genes related to xenobiotics biodegradation and metabolism, probably leading to the improved performance in group B. This study indicated that bioaugmentation could promote the removal of nitrogen-containing organic pollutants, which should be an effective strategy for wastewater treatment.     

废溶剂油中二甲苯与醋酸丁酯的回收

以水作为共沸剂,采用间歇萃取精馏法从工业废溶剂油中回收二甲苯和醋酸丁酯,对预处理后的原料进行了萃取精馏。考察了油水比、分离温度、时间等操作参数对分离过程的影响。实验结果表明,在最佳的工艺条件下（回流比为5,V（油）：V（水）=1．5：1）,二甲苯和醋酸丁酯在馏出液中的质量分数均达到99％以上,二甲苯的回收率为84．14％以上,醋酸丁酯的回收率为99．43％。