Mechanisms of allicin exposure for the sludge fermentation enhancement: Focusing on the fermentation processes and microbial metabolic traits

As a frequently used product with antimicrobial activity, consumed allicin might be discharged and concentrated in waste-activated sludge (WAS). However, the influence of allicin (as an exogenous pollutant) on WAS fermentation has not been clearly revealed. This study aimed to disclose the impacts of allicin on volatile fatty acid (VFA) generation during WAS fermentation. The results showed that the appropriate presence of allicin (10 mg/g TSS) significantly enhanced the VFA yield (1894 versus 575 mg COD/L in the control) with increased acetate proportion (24.3%). Further exploration found that allicin promoted WAS solubilization, hydrolysis and acidification simultaneously. Metagenomic analysis revealed that the key genes involved in extracellular hydrolysis metabolism (i.e., CAZymes), membrane transport (i.e., gtsA and ytfT), substrate metabolism (i.e., yhdR and pfkC) and fatty acid synthesis (i.e., accA and accD) were all highly expressed. Allicin also induced the bacteria to produce more signalling molecules and regulate cellular functions, thereby enhancing the microbial adaptive and regulatory capacity to the unfavourable environment. Moreover, the variations in fermentative microbes and their contributions to the upregulation of functional genes (i.e., ytfR, gltL, INV, iolD and pflD) for VFA generation were disclosed. Overall, the simultaneous stimulation of functional microbial abundances and metabolic activities contributed to VFA production in allicin-conditioned reactors.     

槽式太阳能热电站光污染问题分析

槽式太阳能热电站正常运行情况下会不可避免地产生光污染问题。本文分析了槽式太阳能热电站产生光污染的原因以及光污染对人和生态环境产生的影响。在槽式太阳能电站选址阶与运行阶段,分别提出了有效的光污染防治措施,为今后槽式太阳能热电站光污染防治提供了一定的参考依据。     

啶虫脒在甘蓝和土壤中的残留消解动态研究

采用田间试验及气相色谱检测方法,研究了啶虫脒在甘蓝(Brassica oleracea L.var.capitata L.)和土壤中的残留消解动态.结果表明,啶虫脒在甘蓝和土壤中消解较快.在甘蓝中半衰期为1.4～1.6 d,药后3d消解90%以上;在土壤中的半衰期为1.8～1.9 d,药后7 d消解90%以上.3%啶虫脒可湿性粉剂,45、22.5 g·hm-2,施药2次,药后3、5、7 d苹果和土壤中残留量均小于2 mg·kg-1.     

桂林市水环境问题分析与对策

本文分析了桂林市面临的缺水、水污染严重、水环境设施不足、水旱灾害加剧等水环境问题及原因，并探讨了解决问题的对策：对水资源的保护与开发实行统一规划和管理；保护水源林，提高林木覆盖率；采取适当的蓄水补水工程措施；提高环保投入，加强污染综合防治；节约用水大有潜力；合理布局，优化产业结构     

折弯机通用组合上模结构的改进和设计

通过对新、旧2种折弯机组合上模从工艺结构、受力分析、设计要点及调节使用等方面进行全面的比较和分析,提出一种新的、合理的上模结构——偏心销式分段有量度调节结构的折弯机组合上模.     

流域水资源标准体系风险分析与对策

为实施流域水资源有效保护,从技术管理层面分析流域水资源共享过程中标准体系的构成与作用。对现阶段实施的生活饮用水卫生标准、地表水环境质量标准和排水标准中涵盖的有机污染物进行对称性分析,指出标准体系中存在的技术风险以及生活污水和工业废水混排存在的管理风险。以松花江流域中某化工厂排水为实例进行有机污染物成份检测,发现了标准体系对污染物监控存在的疏漏。提出从人体健康角度完善排水和水环境质量标准,从流域水资源共享角度对排水和给水设施进行整体规划和布局,从水资源安全保障角度建立流域有机污染物优先控制名单。     

基于ERICA的生物辐射剂量评价

电离辐射防护不仅要保护人类而且要保护非人类生物,这是辐射防护概念的一个重大变化,也是生态保护的一大重要举措。本文概述了欧盟生物辐射剂量评价方法 FASSSET的框架体系结构、参考生物和剂量学模型。本文以某内陆核电厂为例,采用ERICA方法对该核电厂水生生物的辐射影响进行了预测计算。计算结果表明,该内陆核电厂2台百万千瓦级核电机组正常运行时对水生生物的辐射剂量率低于国际组织推荐的400μGy.h-1控制限值和ERICA的筛选剂量值10μGy.h-1。因此,该内陆核电厂不会对厂址附近水域水生生物造成不利影响。ERICA方法可作为中国现阶段开展生物辐射剂量评价的推荐方法。     

Source and deposition of polycyclic aromatic hydrocarbons to Shanghai, China

Despite recent efforts to investigate the distribution and fate of polycyclic aromatic hydrocarbons (PAHs) in air, water, and soil, very little is known about their temporal change in wet deposition. As a result of increased attention to public health, a large-scale survey on the deposition flux and distribution of PAH contamination in rainwater was urgently conducted in Shanghai, China. In this study, 163 rainwater samples were collected from six sites, and 15 PAH compounds were detected by the use of a simple solid phase microextraction (SPME) technique coupled with gas chromatography-mass spectrometry. The dominant PAH species monitored were naphthalene, phenanthrene, anthracene, and fluoranthene. The concentration of total PAHs per event was between 74 and 980 ng/L, with an average value of 481 ng/L, which is at the high end of worldwide figures. The annual deposition flux of PAHs in rainwater was estimated to be 4148 kg/yr in the Shanghai area, suggesting rainfall as a major possible pathway for removing PAHs from the atmosphere. Diagnostic analysis by the ratios of An/178 and Fl/Fl+Py suggested that combustion of grass, wood, and coal was the major contributor to PAHs in the Shanghai region. Back trajectory analysis also indicated that the pollutant sources could be from the southern part of China.     

锰电解行业铬钝化剂回收利用技术研究

以某电解锰工艺末端铬钝化废水为研究对象,采用氧化、除杂、反应制得成品,污水达标处理及回用的组合工艺,制备达到国家标准的中铬黄产品,以实现铬的回收利用。结果表明:对于H2O2氧化工艺,选用V(水样)/V(30%H2O2)为(600～1000):1;可采取加碱沉淀Mn的工艺去除杂质金属离子;铬酸铅的生成反应适宜温度为55～60℃,硝酸铅投加量为理论值的1.05倍～1.10倍;采取加石灰调pH、投加硫酸铝的方法可去除水样中剩余铅离子,V(上清液)/V(5%硫酸铝溶液)为1000～2000较合适;生产该产品基本上能够做到保本、微利,但具有显著的环境效益和社会效益。     

2013年成都地区一次秸秆焚烧特征及成因分析

2013年9月14~17日成都及周边地区出现了一次秸秆焚烧空气污染过程,成都、德阳受污染影响较严重,乐山、眉山影响相对较轻。基于空气污染指数API,结合雷达消光系数反演图、在线气团后向轨迹及探空斜温图分析本次空气污染过程,主要是由成都城区以南地区秸秆焚烧及区域边界层辐射逆温等不利扩散气象条件共同造成的。