间歇曝气潜流人工湿地的污水脱氮效果

采用间歇曝气运行方式,提升潜流人工湿地生活污水处理系统中的溶解氧浓度,强化脱氮效果。结果表明,间歇曝气运行方式有效提高了湿地内部溶解氧水平,曝气时溶解氧浓度可达6~9 mg/L,停止曝气后,溶解氧浓度迅速下降至0.5 mg/L以下,在湿地内部营造了一种交替的好氧和缺氧环境,分别促进好氧硝化和缺氧反硝化作用。在水力停留时间为3 d的情况下,间歇曝气潜流人工湿地系统对氨氮、总氮和COD的去除率分别可达到98.0%、87.6%和96.3%,较常规潜流人工湿地系统分别提高了74.1%、56.4%和18.1%,实现了氨氮、总氮和COD的同步高效去除。     

Total nitrogen and community turnover determine phosphorus use efficiency of phytoplankton along nutrient gradients in plateau lakes

Numerous studies support that biodiversity predict most to ecosystem functioning, but whether other factors display a more significant direct impact on ecosystem functioning than biodiversity remains to be studied. We investigated 398 samples of the phytoplankton phosphorus resource use efficiency (RUE_P = chlorophyll-a concentration/dissolved phosphate) across two seasons in nine plateau lakes in Yunnan Province, China. We identified the main contributors to phytoplankton RUE_P and analyzed their potential influences on RUE_P at different lake trophic states. The results showed that total nitrogen (TN) contributed the most to RUE_P among the nine lakes, whereas community turnover (measured as community dissimilarity) explained the most to RUE_P variation across the two seasons. Moreover, TN also influenced RUE_P by affecting biodiversity. Species richness (SR), functional attribute diversity (FAD2), and dendrogram-based functional diversity (FDc) were positively correlated with RUE_P in both seasons, while evenness was negatively correlated with RUE_P at the end of the rainy season. We also found that the effects of biodiversity and turnover on RUE_P depended on the lake trophic states. SR and FAD2 were positively correlated with RUE_P in all three trophic states. Evenness showed a negative correlation with RUE_P at the eutrophic and oligotrophic levels, but a positive correlation at the mesotrophic level. Turnover had a negative influence on RUE_P at the eutrophic level, but a positive influence at the mesotrophic and oligotrophic levels. Overall, our results suggested that multiple factors and nutrient states need to be considered when the ecosystem functioning predictors and the biodiversity-ecosystem functioning relationships are investigated.     

Evidence on the causes of the rising levels of CODMn along the middle route of the South-to-North Diversion Project in China: The role of algal dissolved organic matter

As the biggest inter-basin water transfer scheme in the world,the South-to-North Water Diversion Project（SNWD） was designed to alleviate the water crisis in North China.The main channel of the middle route of the SNWD is of great concern in terms of the drinking water quality.In this study,we tested the hypothesis that the dissolved organic matter（DOM） derived from the planktonic algae causes the rising levels of COD_Mn along the middle route by monitoring data on water quality（2015-20...     

Hybrid zeolite-based ion-exchange and sulfur oxidizing denitrification for advanced slaughterhouse wastewater treatment

The discharge of slau ghterhouse wastewater（SWW） is incre asing and its wastewater has to be treated thoroughly to avoid the eutrophication.The hybrid zeolite-based ion-exchange and sulfur autotrophic denitrification（IX-AD） process was developed to advanced treat SWW after traditional secondary biological process.Compared with traditional sulfur oxidizing denitrification（SOD）,this study found that IX-AD column showed:（1） stronger ability to resist NO₃^-pollution load,（2） low...     

镍基催化剂对污泥微波热解制生物气效能的影响

为实现污水污泥减量化、无害化及资源化的目标,在微波热解污水污泥基础上,进行了镍基催化剂对制取生物气效能影响的研究。采用元素分析对污泥元素进行检测,气/质联用分析(GC-MS)和气相色谱(GC)对热解生物气的组成和含量进行测定。实验结果表明,镍基催化剂的添加对微波热解污水污泥制取生物气有较大促进作用。5%添加量与800℃热解终温条件下具有最佳催化效果:生物气中H2、CO产量最大,H2产量由29 g/kg增加到35.8 g/kg,提升23.4%,CO产量由302.7 g/kg增加到383.3 g/kg,提升26.6%;同时催化剂还能提高热能利用效率,降低热解终温,即5%添加量在700℃热解终温时可达到空白800℃时的产气效果;镍基催化剂主要在500~600℃时发挥催化作用,加快了H2和CO的释放。微波热解污泥制取的生物气具有产量大、富含H2与CO等优点,可推动污水污泥的资源化进程。     

A method to extract algae toxin of microcystin-LR

A simple and low-cost method to obtain cyanobacterial toxin microcystin-LR(MC-LR) was developed. A new strain of Microcystis aeruginosa,named DC-1, producing microcystin-LR but not microcystin-RR, was separated from the field blooming algae samples of Dianchi Lake.in southwest of China. Following three times‘freeze and thaw treatment, the cultivated DC-cells were extracted with 40% methanol in water.The extract was centrifuged and the supernatant applied to a Hydrophilic-Lipophilic Balance(HLB) SPE cartridge.Eluted impuries with a certain gradient from 30% to 50% methanol in water, MC-LR was finally eluted from the HLB cartridge with 60%.may be used in adsorption and biodegradation experiments instead of using expensive standard reagents.     

T-2毒素的毒性效应及致毒机制研究进展

T-2毒素是由多种镰刀菌产生的单端孢霉烯族化合物中毒性较强的一种毒素,广泛存在于谷物和谷类食品中.经食物连续摄入T-2毒素会对人类和动物的健康造成潜在危害.目前,T-2毒素对人和动物健康的影响受到了社会的广泛关注,已成为毒理学领域研究的热点课题之一.在综述了T-2毒素的生物转化、代谢途径及其毒理学效应与机制基础上,对现...     

生理毒代动力学模型及其在有机污染物水生生态毒理研究中的应用

人类生产和生活使用各种人工合成的化学品,种类和数量急剧增长,对生态系统和人体健康造成了极大威胁。因此,亟需采用高效的方法对数量巨大的化合物进行毒性评价。对生理毒代动力学(PBTK)模型的建立过程及其在污染物生态毒理研究中的应用进行了综述。PBTK模型,又称生理药代动力学(PBPK)模型,是利用生理学和解剖学等原理,将生物体简化为用血流连接的肝、肾和脂肪等各组织器官房室,模拟化合物在生物体内的吸收、分布、代谢和排泄过程。模型参数包括生理参数和生化参数2个部分,可用MATLAB等软件进行模拟。模型已应用于数百余种有机污染物在鱼体等水生生物体的毒代动力学模拟。已有模拟结果能够预测化合物在生物体内的有效剂量,对化合物毒性进行评估,并可用于不同物种、不同剂量和不同暴露途径间的外推,有力推进了污染物生态毒理研究工作的开展。     

集成DEMATEL-ISM的古建筑火灾致因因素评价

为深入了解古建筑火灾事故致因因素,提高古建筑消防安全管理水平,基于事故致因理论,采用德尔菲法从人员、古建筑消防系统、古建筑防火能力、安全管理与环境五个方面确定18个古建筑火灾致因因素,并建立古建筑火灾事故评价指标体系。同时运用实验室决策分析法(DEMATEL)构建矩阵对古建筑火灾致因因素进行分析。一方面,通过原因度定量结果对古建筑火灾致因因素的属性进行分类,确定其属于火灾原因因素还是结果因素;另一方面,通过中心度指标评价古建筑火灾各个致因因素的重要程度。进而利用解释结构模型(ISM)将致因因素进行层级划分,构建5层3阶的多级递阶模型,分析致因因素间的耦合和交互关系。结果表明,古建筑火灾事故的发生是近邻原因、过渡原因及本质原因共同作用的结果,并针对这三方面确定古建筑火灾事故重点管控方向。同时,在古建筑消防安全管理中,应重点关注中心度较大的致因因素。     

中国主粮作物生物炭产量效应的Meta分析

为定量评估生物炭对主粮作物产量的影响,收集了公开发表的116篇相关文献,共866对数据,采用Meta分析法定量分析了生物炭对我国主粮作物产量的影响及其影响因子,同时构建结构方程模型(SEM)进一步解释了因子间的交互关系.结果表明,与不施用生物炭相比,生物炭施用后可改善主粮田土壤理化性质,提高主粮作物产量,平均增产率为8.77%.其中,当生物炭pH为7～8时,平均增产率最大,可达26.49%;其C/N<60时,平均增产率为13.73%,显著高于C/N≥60的平均增产率.将生物炭施入酸性或中性土壤中,更能发挥其增产效应.当施炭量为10～20 t·hm^-2时,小麦和玉米的平均增产率最大;施炭量为15～25 t·hm^-2时,水稻平均增产率最大.但是,不同施炭水平的水稻增产率相近,可考虑损失部分产量,适当减施以兼顾经济效益.此外,生物炭增产效应会随施用年限增加而不断减弱,一般3 a后增产不显著.SEM表明生物炭施用量不仅直接影响主粮作物产量,还通过改善土壤肥力间接影响主粮作物产量,而生物炭C/N和pH仅通过改善土壤肥力影响主粮作物产量.因此,今后...