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661.
Alkhafaji R. Abood Jianguo Bao Jiangkun Du Dan Zheng Ye Luo 《Waste management (New York, N.Y.)》2014,34(2):439-447
This study describes the complete treatment of non-biodegradable landfill leachate by combined treatment processes. The processes consist of agitation as a novel stripping method used to overcome the ammonia toxicity regarding aerobic microorganisms. The NH3-N removal ratio was 93.9% obtained at pH 11.5 and a gradient velocity (G) 150 s?1 within a five-hour agitation time. By poly ferric sulphate (PFS) coagulation followed the agitation process; chemical oxygen demand (COD) and biological oxygen demand (BOD5) were removed at 70.6% and 49.4%, respectively at an optimum dose of 1200 mg L?1 at pH 5.0. The biodegradable ratio BOD5/COD was improved from 0.18 to 0.31 during pretreatment step by agitation and PFS coagulation. Thereafter, the effluent was diluted with sewage at a different ratio before it was subjected to sequencing batch reactor (SBR) treatment. Up to 93.3% BOD5, 95.5% COD and 98.1% NH3-N removal were achieved by SBR operated under anoxic–aerobic–anoxic conditions. The filtration process was carried out using sand and carbon as a dual filter media as polishing process. The final effluent concentration of COD, BOD5, suspended solid (SS), NH3-N and total organic carbon (TOC) were 72.4 mg L?1, 22.8 mg L?1, 24.2 mg L?1, 18.4 mg L?1 and 50.8 mg L?1 respectively, which met the discharge standard. The results indicated that a combined process of agitation-coagulation-SBR and filtration effectively eliminated pollutant loading from landfill leachate. 相似文献
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664.
Observed levels and trends of gaseous SO2 and HNO3 at Mt. Waliguan, China: Results from 1997 to 2009
Long-term measurements of SO2 and HNO3,particularly those from the background sites,are rarely reported.We present for the first time the long-term measurements of SO2 and HNO3 at Waliguan(WLG),the only global baseline station in the back-land of the Eurasian Continent.The concentrations of SO2 and HNO3 were observed at WLG from 1997 to 2009.The observed annual mean concentrations of SO2 and HNO3 at WLG were 1.28±0.41 and 0.22±0.19μg/m3,respectively.The HNO3 concentrations were much higher in warmer seasons than in colder seasons,while the SO2 concentrations showed a nearly reversed seasonal pattern.In most months,the concentration of HNO3 was significantly correlated with that of SO2,suggesting that some common factors influence the variations of both gases and the precursors of HNO3 may partially be from the SO2-emitting sources.The SO2 concentration had a very significant(P < 0.0001) decreasing trend(-0.2μg/(m3·yr)) in 1997-2002,but a significant(P < 0.05) increasing trend(+0.06 μg/(m 3 ·yr)) in 2003-2009.The HNO3 concentration showed no statistically significant trend during 1997-2009.While the decrease of SO2 in 1997-2002 agrees with the trend of global SO2 emissions,the increase in 2003-2009 is not consistent with the decreasing trends in many other regions over the world.Trajectory analysis suggests that the airmasses from the northern Qinghai-Tibetan Plateau and the Takla Makan Desert regions contributed significantly to the increasing trends of SO2 and HNO3 at WLG in 2003-2009,with a rate of +0.13μg/(m3·yr) and +0.007μg/(m3·yr),respectively. 相似文献
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针对废弃线路板机械破碎分离产物中贵金属分布特征不明确的现状,以废弃手机和电脑主板为原材料,研究了分离产物中银(Ag)、钯(Pd)的分布规律。结果表明,经机械破碎分离后,Ag在手机和电脑主板金属分离物中的分配率为98.3%、97.6%,在非金属分离物中的分布为1.68%、2.45%,Pd在2类主板的金属分离物中的分配率均为100%。不同破碎颗粒中,Ag在手机主板金属分离物小颗粒(0.12 mm<Ф<0.85 mm)与大颗粒(Ф>0.85 mm)中的分配率为71.7%、26.6%,电脑主板相应为62.7%、34.7%;Pd在手机主板金属分离物2类颗粒中为52.6%、47.5%,电脑主板相应为44.8%、55.2%。在机械破碎过程中,板卡的外层铜箔容易成为小颗粒,而内层铜箔大部分形成大颗粒。物料平衡研究显示,Ag、Pd的回收率分别为96.5%~97.1%、97.3%~98.4%。 相似文献
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将适应性环境管理的模式应用于深圳第26届世界大学生夏季运动会生态环境保障工作,对生态环境保障总目标层层分解落实,由第三方评估机构对任务逐项跟踪管理,定期评估各部门绩效,根据外部条件和内部因素的变化对工作方案和阶段性目标进行动态调整,最大限度地降低了环境管理工作的不确定性。经过六个月的实践应用,大运赛事期间深圳市生态环境保障工作取得了十分显著的成效。 相似文献
669.
利用2018年广东省环珠江口气候环境与空气质量变化野外科学观测研究站70 m气象塔上涡动协方差系统连续观测资料,对不同大气稳定度条件下近地面层相干结构的统计特征及其对湍流通量相似性的影响进行了初步研究.结果表明:(1)无量纲风速标准差(稳定、不稳定)和气温标准差(不稳定)遵循莫宁-奥布霍夫相似理论;(2)湍流速度(u、v、w)谱、温度(T)谱、CO2和H2O浓度谱在惯性副区均满足-2/3定律.w-T协谱、垂直速度(w)与标量(CO2、H2O)浓度的协谱(w-CO2、w-H2O)在惯性副区遵循-4/3定律;(3)不稳定条件下,热力湍流对H2O和CO2标量具有很好的输送作用,而以动量通量输送为代表的机械作用在弱不稳定条件下对H2O和CO2的输送效果最好;(4)上冲和下扫运动对湍流通量输送起主导作用,且随湍涡尺度的变化略有差异,湍流通量输送对大气层结的依赖性较弱. 相似文献
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Weigang Wang Chao Peng Chenjuan Deng Ting Lei Jun Zheng Jun Zhao Dongbin Wang Zhijun Wu Lin Wang Yan Chen Mingyuan Liu Jingkun Jiang Anpei Ye Maofa Ge 《环境科学学报(英文版)》2023,123(1):183-202
Atmospheric nanoparticles are crucial components contributing to fine particulate matter(PM2.5), and therefore have significant effects on visibility, climate, and human health. Due to the unique role of atmospheric nanoparticles during the evolution process from gas-phase molecules to larger particles, a number of sophisticated experimental techniques have been developed and employed for online monitoring and characterization of the physical and chemical properties of atmospheric nanoparticles,... 相似文献