Insights into sludge granulation during anaerobic treatment of high-strength leachate via a full-scale IC reactor with external circulation system

In this study, a full-scale internal circulation(IC) reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste(MSW)incineration plant, in which anaerobic sludge granulation was intensively investigated. Results showed that the IC reactor achieved excellent treatment performance under high organic loading rates(OLR) of 21.06–25.16 kg chemical oxygen demand(COD)/(m3? day). The COD removal efficiency and biogas yield respectively reached 89.4%–93.4% and 0.42–0.50 m3/kg COD.The formation of extracellular polymeric substances(EPS) was closely associated with sludge granulation. Protein was the dominant component in sludge EPS, and its content was remarkably increased from 21.6 to 99.7 mg/g Volatile Suspended Solid(VSS) during the reactor operation. The sludge Zeta potential and hydrophobicity positively correlated with the protein/polysaccharide ratio in EPS, and they were respectively increased from-26.2 m V and 30.35% to-10.6 m V and 78.67%, which was beneficial to microbial aggregation. Three-dimensional fluorescence spectroscopy(3 D-EEM) and Fourier transform infrared spectroscopy(FT-IR)analysis further indicated the importance of protein-like EPS substances in the sludge granulation. Moreover, it was also found that the secondary structures of EPS proteins varied during the reactor operation.     

β-环糊精/环氧氯丙烷聚合物的制备及其对双酚S的吸附特性

BPS（双酚S）用途广泛,但存在水环境污染问题,容易引起类似于双酚A的雌激素反应,因此需要寻求高效的吸附剂从水溶液中将其脱除.在NaOH水溶液中,以环氧氯丙烷为交联剂,合成了β-CDP（β-环糊精/环氧氯丙烷聚合物）,用于吸附水溶液中的BPS.基于此,考察了吸附时间、pH、初始ρ（BPS）、β-CDP用量对吸附性能的影响以及β-CDP的再生性能,探讨了吸附动力学、等温吸附模型和吸附机理.结果表明:①在温度为298 K、pH为5.4、β-CDP用量为0.05 g、初始ρ（BPS）为100 mg/L、BPS溶液体积为50 mL、吸附时间为60 min的条件下,BPS吸附量为69.7 mg/g,吸附率为69.7%;②吸附动力学符合准二级动力学模型,表明化学吸附为速率控制步骤;③Langmuir吸附等温模型的成功拟合表明,吸附BPS在β-CDP表面上形成了单分子层覆盖;④β-CDP吸附BPS为放热过程,低温有利于吸附的进行;⑤与初始吸附量（69.7 mg/g）相比,β-CDP连续再生6次,BPS吸附量仍可达68.1 mg/g;⑥吸附机理是通过BPS的羟基与β-CDP形成氢键作为推动力,并借助β-CD（β-环糊精）空腔内部的疏水作用,使得BPS进入空腔形成包结物.研究显示,β-CDP对水溶液中的BPS具有良好的吸附性能,再生循环使用稳定性高,具有较高的性价比.      

DIDP通过线粒体-Caspase途径诱导昆明小鼠肝脏损伤的研究

为探究DIDP（Di-iso-decyl phthalate,邻苯二甲酸二异癸酯）对肝脏的影响及其可能的分子机制,以昆明小鼠为研究对象,选用Res（resveratrol,白藜芦醇）为抗氧化剂,分别设置对照组,0.15、1.5、15、150 mg/（kg·d）DIDP组,Res组,150 mg/（kg·d）DIDP+Res组,灌胃染毒9 d后,对小鼠肝脏切片进行HE染色观察,并检测ROS（reactive oxygen,活性氧）、GSH（glutathione,谷胱甘肽）、MDA（malondialdehyde,丙二醛）、Cyt-C（cytochromec,细胞色素C）、Caspase-3和血清中的ALT（alanine aminotransferase,丙氨酸氨基转移酶）含量.结果表明:与对照组相比,15、150 mg/（kg·d）DIDP组小鼠血清中ALT含量极显著上升（P < 0.01）;HE染色结果显示,15、150 mg/（kg·d）DIDP组小鼠出现肝细胞水肿、肝索紊乱、肝窦以及肝中央静脉扩张等现象;15、150 mg/（kg·d）DIDP组小鼠肝脏ROS含量显著上升（P < 0.05）,GSH含量显著下降（P < 0.05）,150 mg/（kg·d）DIDP组小鼠肝脏MDA含量极显著上升（P < 0.01）;1.5、15、150 mg/（kg·d）DIDP组小鼠肝脏中c（Cyt-C）极显著上升（P < 0.01）;15、150 mg/（kg·d）DIDP组小鼠肝脏中Caspase-3表达量极显著上升（P < 0.01）.DIDP染毒剂量的增加对肝脏的各种损伤程度呈上升趋势,Res可减轻上述DIDP对肝脏造成的各种损伤.研究显示,15、150 mg/（kg·d）DIDP可诱导肝脏组织氧化应激水平上升,进而造成线粒体损伤,导致细胞凋亡,造成肝功能受损,因此,线粒体-Caspase途径可能是DIDP诱导肝脏损伤的潜在机制之一.      

Are current Chinese national ambient air quality standards on 24-hour averages for particulate matter sufficient to protect public health?

With rapid economic development and urbanization in recent decades, China has experienced the worsening of ambient air quality. For better air quality management to protect human health, Chinese government revised national ambient air quality standards(NAAQS) for particulate matter(PM) in 2012(GB3095-2012). To assess the effectiveness of current NAAQS for PM on public health in Chinese population, we conducted a metaanalysis on published studies examining the mortality risk of short-term exposure to PM with aerodynamic diameters less than 10 and 2.5 μm(PM_(10) and PM_(2.5)) in China. The reported24-hour concentrations of PM_(10) and PM_(2.5) in studies ranged from 43.5 to 150.1 μg/m~3 and 37.5 to 176.7 μg/m~3. In the pooled excess, mortality risk estimates of short-term exposure to PM.In specific, per 10 μg/m~3 increase in PM_(10), we observed increases of 0.40%(95%CI: 0.33%,0.47%), 0.57%(95%CI: 0.44%, 0.70%) and 0.49%(95%CI: 0.40%, 0.58%) in total, respiratory and cardiovascular mortality, per 10 μg/m~3 increase in PM_(2.5), we observed increases of 0.51%(95%CI: 0.38%, 0.63%), 0.62%(95%CI: 0.52%, 0.73%) and 0.75%(95%CI: 0.54%, 0.95%) in total,respiratory and cardiovascular mortality. Finally, we derived 125 μg/m~3 for PM_(10) and 62.5 μg/m~3 for PM_(2.5) as 24-hour recommendation values based on the pooled estimates. Our results indicated that current Chinese NAAQS for PM could be sufficient in mitigating the excess mortality risk from short-term exposure to ambient PM. However, future research on longterm exposure cohort studies in Chinese population is also essential in revising annual averages for PM in Chinese NAAQS.     

Observation and analysis of atmospheric volatile organic compounds in a typical petrochemical area in Yangtze River Delta, China

Volatile organic compounds (VOCs) are a kind of important precursors for ozone photochemical formation. In this study, VOCs were measured from November 5th, 2013 to January 6th, 2014 at the Second Jinshan Industrial Area, Shanghai, China. The results showed that the measured VOCs were dominated by alkanes (41.8%), followed by aromatics (20.1%), alkenes (17.9%), and halo-hydrocarbons (12.5%). The daily trend of the VOC concentration showed a bimodal feature due to the rush-hour traffic in the morning and at nightfall. Based on the VOC concentration, a receptor model of Positive Matrix Factorization (PMF) coupled with the information related to VOC sources was applied to identify the major VOC emissions. The result showed five major VOC sources: solvent use and industrial processes were responsible for about 30% of the ambient VOCs, followed by rubber chemical industrial emissions (23%), refinery and petrochemical industrial emissions (21%), fuel evaporations (13%) and vehicular emissions (13%). The contribution of generalized industrial emissions was about 74% and significantly higher than that made by vehicle exhaust. Using a propylene-equivalent method, alkenes displayed the highest concentration, followed by aromatics and alkanes. Based on a maximum incremental reactivity (MIR) method, the average hourly ozone formation potential (OFP) of VOCs is 220.49?ppbv. The most significant source for ozone chemical formation was identified to be rubber chemical industrial emissions, following one by vehicular emission. The data shown herein may provide useful information to develop effective VOC pollution control strategies in industrialized area.     

Soot reduction by addition of dimethyl carbonate in normal and inverse ethylene diffusion flames: Nanostructural evidence

Oxygenated fuel represents an attractive alternative as an additive for reducing soot emissions.Dimethyl carbonate(DMC) is an oxygenated compound which is a good option to reduce soot,but the detailed characteristics of soot produced from combustion of hydrocarbon fuels blended with DMC are still lacking. The present research studied the nanostructure and reactivity of soot particles in ethylene/DMC normal and inverse diffusion flames. High resolution transmission electron microscopy(HRTEM), X-ray diffraction(XRD), and thermogravimetric analysis(TGA)were used to analyze the nanostructure and reactivity of soot. It was found that DMC addition was effective in decreasing the average weights of soot formed in flames. The results of HRTEM images showed that soot particles obtained with DMC addition showed liquid-like material and tight bonding, and exhibited more highly disorganized layers, which give it higher reactivity than soot obtained without DMC addition. Furthermore, HRTEM was used to analyze soot fringe characteristics consisting of fringe tortuosity, fringe length, and fringe separation. XRD was used to crosscheck the results for fringe separation, and was consistent with HRTEM results. In addition, the mass loss curve of TGA experiments showed that DMC addition could enhance the reactivity of soot particles.     

A comprehensive classification method for VOC emission sources to tackle air pollution based on VOC species reactivity and emission amounts

In China, volatile organic compound(VOC) control directives have been continuously released and implemented for important sources and regions to tackle air pollution. The corresponding control requirements were based on VOC emission amounts(EA), but never considered the significant differentiation of VOC species in terms of atmospheric chemical reactivity. This will adversely influence the effect of VOC reduction on air quality improvement. Therefore,this study attempted to develop a comprehensive classification method for typical VOC sources in the Beijing–Tianjin–Hebei region(BTH), by combining the VOC emission amounts with the chemical reactivities of VOC species. Firstly, we obtained the VOC chemical profiles by measuring 5 key sources in the BTH region and referencing another 10 key sources, and estimated the ozone formation potential(OFP) per ton VOC emission for these sources by using the maximum incremental reactivity(MIR) index as the characteristic of source reactivity(SR). Then, we applied the data normalization method to respectively convert EA and SR to normalized EA(NEA) and normalized SR(NSR) for various sources in the BTH region.Finally, the control index(CI) was calculated, and these sources were further classified into four grades based on the normalized CI(NCI). The study results showed that in the BTH region,furniture coating, automobile coating, and road vehicles are characterized by high NCI and need to be given more attention; however, the petro-chemical industry, which was designated as an important control source by air quality managers, has a lower NCI.     

Identifying water resources management strategies in adaptation to climate change under uncertainty

In this study, an integrated simulation-based allocation modeling system (ISAMS) is developed for identifying water resources management strategies in response to climate change. The ISAMS incorporates global climate models (GCMs), a semi-distributed land use-based runoff process (SLURP) model, and a multistage interval-stochastic programming (MISP) approach within a general framework. The ISAMS can not only handle uncertainties expressed as probability distributions and interval values but also reveal climate change impacts on water resources allocation under different projections of GCMs. The ISAMS is then applied to the Kaidu-kongque watershed with cold arid characteristics in the Tarim River Basin (the largest inland watershed basin in China) for demonstrating its efficiency. Results reveal that different climate change models corresponding to various projections (e.g., precipitation and temperature) would lead to changed water resources allocation patterns. Variations in water availability and demand due to uncertainties could result in different water allocation targets and shortages. A variety of decision alternatives about water allocations adaptive to climate change are generated under combinations of different global climate models and ecological water release plans. These findings indicate that understanding the uncertainties in water resources system, building adaptive methods for generating sustainable water allocation patterns, and taking actions for mitigating water shortage problems are key adaptation strategies responding to climate change.     

臭氧-生物活性炭对微污染原水中典型持久性有机物的去除效果

以长三角地区J市典型有机微污染水源P水厂为研究对象,考察了臭氧-生物活性炭深度处理工艺对微污染水源水中有机物的去除效果.结果表明,臭氧-生物活性炭深度处理使高锰酸盐指数、总有机碳(TOC)和UV254的平均去除率分别提升19. 2%、10. 4%和23. 0%.水厂原水中检出8种多环芳烃(polycyclic aromatic hydrocarbon,PAHs)、16种有机氯农药(organochlorine pesticides,OCPs)、5种卤乙酸(haloacetic acids,HAAs),其总浓度分别为53. 9~100. 0、6. 5~41. 8、2. 5×103~1. 1×104ng·L~(-1),臭氧-生物活性炭深度处理对多环芳烃和有机氯农药的平均去除率分别为32. 5%和25. 9%,比常规处理工艺出水的水质有显著提升.卤乙酸的去除率为33. 8%~87. 0%,主要通过常规处理工艺去除;臭氧-生物活性炭深度处理对氯代乙酸略有去除,溴代乙酸有少量生成.     

成渝城市群臭氧污染特征及影响因素分析

为研究成渝城市群O_3污染特征及其影响因素,对成渝城市群15个城市2015—2016年国控环境监测站点和国家气象台站数据进行了研究.结果表明,研究区域15个城市均存在不同程度的O_3超标现象.2015—2016年成渝城市群O_3污染形势愈发严峻,春末及夏季污染最为严重,且在7月达到O_3浓度峰值(118μg·m~(-3)),O_3污染空间分布呈片状,以资阳为中心的遂宁、眉山、成都等城市为O_3污染较为严重的区域.颗粒物、NO_2及CO均与O_3有显著相关性,其中,颗粒物与O_3浓度在冬季呈负相关,在夏季则表现为正相关.太阳辐射、气温、相对湿度及流场均是影响O_3浓度的重要因子,强辐射、高温及低湿易形成较高浓度的O_3,相对湿度对O_3浓度的影响呈先升后降的关系.