Reaction mechanism of arsenic capture by a calcium-based sorbent during the combustion of arsenic-contaminated biomass: A pilot-scale experience

Pilot-scale combustion is required to treat arsenic-enriched biomass in China. CaO addition to arsenic-enriched biomass reduces arsenic emission. CaO captures arsenic via chemical adsorption to form Ca₃(AsO₄)₂. Large quantities of contaminated biomass due to phytoremediation were disposed through combustion in low-income rural regions of China. This process provided a solution to reduce waste volume and disposal cost. Pilot-scale combustion trials were conducted for in site disposal at phytoremediation sites. The reaction mechanism of arsenic capture during pilot-scale combustion should be determined to control the arsenic emission in flue gas. This study investigated three Pteris vittata L. biomass with a disposal capacity of 600 kg/d and different arsenic concentrations from three sites in China. The arsenic concentration in flue gas was greater than that of the national standard in the trial with no emission control, and the arsenic concentration in biomass was 486 mg/kg. CaO addition notably reduced arsenic emission in flue gas, and absorption was efficient when CaO was mixed with biomass at 10% of the total weight. For the trial with 10% CaO addition, arsenic recovery from ash reached 76%, which is an ~8-fold increase compared with the control. Synchrotron radiation analysis confirmed that calcium arsenate is the dominant reaction product.     

Source attribution for mercury deposition with an updated atmospheric mercury emission inventory in the Pearl River Delta Region,China

Estimated anthropogenic Hg emission was 11.9 tons in Pearl River Delta for 2014. Quantifying contributions of emission sources helps to provide control strategies. More attentions should be paid to Hg deposition around the large point sources. Power plant, industrial source and waste incinerator were priorities for control. A coordinated regional Hg emission control was important for controlling pollution. We used CMAQ-Hg to simulate mercury pollution and identify main sources in the Pearl River Delta (PRD) with updated local emission inventory and latest regional and global emissions. The total anthropogenic mercury emissions in the PRD for 2014 were 11,939.6 kg. Power plants and industrial boilers were dominant sectors, responsible for 29.4 and 22.7%. We first compared model predictions and observations and the results showed a good performance. Then five scenarios with power plants (PP), municipal solid waste incineration (MSWI), industrial point sources (IP), natural sources (NAT), and boundary conditions (BCs) zeroed out separately were simulated and compared with the base case. BCs was responsible for over 30% of annual average mercury concentration and total deposition while NAT contributed around 15%. Among the anthropogenic sources, IP (22.9%) was dominant with a contribution over 20.0% and PP (18.9%) and MSWI (11.2%) ranked second and third. Results also showed that power plants were the most important emission sources in the central PRD, where the ultra-low emission for thermal power units need to be strengthened. In the northern and western PRD, cement and metal productions were priorities for mercury control. The fast growth of municipal solid waste incineration were also a key factor in the core areas. In addition, a coordinated regional mercury emission control was important for effectively controlling pollution. In the future, mercury emissions will decrease as control measures are strengthened, more attention should be paid to mercury deposition around the large point sources as high levels of pollution are observed.     

苏北里下河地区湿地资源可持续利用的思考

以里下河地区湿地资源利用为例 ,剖析湿地资源开发过程中带来的相关环境问题 ,包括 :湿地面积缩小 ,自然灾害濒发 ;区内环境状况日趋恶化 ,生产与生活性污染严重 ;湿地功能日益衰退 ;湿地农业生产效益下降 ,农民的生产投入明显不足。此外 ,还探讨湿地生态系统可持续利用对策 ,具体有 :建立湿地可持续利用新的评价指标与标准 ,建立预警分析系统 ,以现代湿地生态工程技术为指导 ,全面提高湿地利用的社会、经济、环境综合效益     

“W型低NOx环保燃烧器”特点及应用状况

“W型低NOx环保燃烧器”采用先进的复合多级混合式雾化技术，强化喷射、混合和扩散，燃烧充分从而控制NOx生成。     

重庆市实施大气二氧化硫污染物排放标准影响研究

通过应用箱工模型，模拟研究了实施排放标准对大气环境质量的影响，分析讨论了实施２排放标准的技术经济可行性。得出如下结论：（１）重庆市实施大气二氧化硫污染物排放标准能基本满足在气环境质量减级标准的要求。（２）实施标准所需二氧化硫治理静态投资费用总额计２６．３６９亿元。（３）实施标准减少环境污染损失６．４４０亿元。     

Seasonal variations of monoterpene emissions from coniferous trees of different ages in Korea

Seasonal variations of emission rates and compositions from coniferous species were measured under controlled conditions using a vegetation enclosure method. Total emission rates and compositions of monoterpene compounds from young and adult trees in different seasons were compared.

It was found that the total emission rates and the components of monoterpene varied significantly with tree species, age, and season. Total emissions from C. japonica and P. koraiensis were higher for older trees than for younger trees; however, significantly higher emissions were found from younger trees for C. obtusa. Higher monoterpene emission rates from each plant were found in spring and summer compared with autumn and winter emissions.     

Examination of dioxin fluxes recorded in dated aquatic-sediment cores in the Kanto region of Japan using multivariate data analysis

Past dioxin (coplanar polychlorinated biphenyl (Co-PCB), 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin (PCDD) and 2,3,7,8-substituted polychlorinated dibenzofuran (PCDF)) fluxes recorded in dated aquatic-sediment cores were analyzed using principal component analysis (PCA). The data set consisted of samples from four cores collected from the Kanto region of Japan. Time trends and spatial differences in the dioxin flux were examined, and the potential relationship to emission sources was investigated. Twenty-five compounds and 58 core slices, corresponding to the later half of the 20th century, were subjected to the analysis. The PCA of both log-transformed and maximum-value-standardized data successfully divided the dioxin compounds into a small number of groups, and three similar clusters of Co-PCBs, PCDDs and penta- to hepta-CDFs were identified. PCB formulations used in the past are judged to have been responsible for the major part of the Co-PCB flux recorded in the sediment cores. However, the relationship to emission sources needs further investigation. It is suggested that most 2,3,7,8-substituted PCDDs and PCDFs are different from Co-PCBs in their emission sources or movements in the environment. The subcore clusters obtained from the PCA of log-transformed data show that the cores from different sampling areas exhibited distinct dioxin fluxes and compositions. Common time trends among the cores were more effectively summarized by the PCA of maximum-value-standardized data focusing on relative time trends. PC scores show that recently the flux of each dioxin compound in the four cores has been generally declining after having reached a peak.     

排污收费对企业污染控制技术创新激励作用的研究

运用模型方法研究了排污收费和行政手段对企业污染控制技术创新的激励作用,为环境管理政策应用提供了理论依据。结果表明,无论对创新企业还是模拟企业,在“技术创新－创新扩散－最优啮合反应”的技术创新过程中,排污收费更能刺激企业的污染控制技术创新行为。     

日本二噁英减排控制的历程、经验与启示

二噁英减排控制是《关于持久性有机污染物的斯德哥尔摩公约》的重要任务,是履行公约义务的难点.对日本二噁英减排控制20年来的实践历程进行了回顾和分析,总结出了其协调管理机制设立、法律法规标准建立、监测能力建设以及宣传教育等八个方面的成功经验,对中国二噁英减排控制工作有重要的借鉴意义.     

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.