On–off control of aeration time in the simultaneous removal of ammonia and manganese using a biological aerated filter system

The biological aerated filter (BAF) system, a new alternative in drinking water treatment, was designed to remove NH₄⁺–N and Mn²⁺ simultaneously. This study aimed to control the aeration time in the BAF system for simultaneous NH₄⁺–N and Mn²⁺ removal to achieve the Malaysian effluent quality regulation for drinking water. The experiment was conducted under four strategies of S1, S2, S3 and S4. The results demonstrated that acceptable levels of NH₄⁺–N and Mn²⁺ were achieved over a 6 h aeration period (S1), producing effluent concentrations of 0.7 mg/L (93.2% removal) and 0.08 mg/L (79.6% removal), respectively. At the initial treatment of S1 and S2, the dissolved oxygen (DO) level rapidly increased until it reached a saturated concentration (6.8 mg/L DO) after 2 h period. Automatic on–off aeration time to maintain 3 mg/L DO set point (S4) resulted with a good effluent quality of NH₄⁺–N and Mn²⁺ compared with the 2 mg/L DO set point (S3) which did not meet the regulated standard limits. Through the automatic on–off aeration time, the saturated and excessive DO levels in the BAF system can be avoided consequently reduce the wastage of energy and electrical consumption for simultaneous NH₄⁺–N and Mn²⁺ removal from drinking water treatment.     

High-performance Si-Containing anode materials in lithium-ion batteries:A superstructure of Si@Co–NC composite works effectively

To mitigate the massive volume expansion of Si-based anode during the charge/discharge cycles, we synthesized a superstructure of Si@Co–NC composite via the carbonization of zeolite imidazolate frameworks incorporated with Si nanoparticles. The Si@Co–NC is comprised of Si-nanoparticle core and N-doped/Co-incorporated carbon shell, and there is void space between the core and the shell. When using as anode material for LIBs, Si@Co–NC displayed a super performance with a charge/discharge capacity of 191.6/191.4 mA h g-1 and a coulombic efficiency of 100.1％ at 1000 mA g-1 after 3000 cycles, and the capacity loss rate is 0.022％ per cycle only. The excellent electrochemical property of Si@Co–NC is because its electronic conductivity is enhanced by doping the carbon shell with N atoms and by incorporating with Co particles, and the pathway of lithium ions transmission is shortened by the hollow structure and abundant mesopores in the carbon shell. Also, the volume expansion of Si nanoparticles is well accommodated in the void space and suppressed by the carbon host matrix. This work shows that, through designing a superstructure for the anode materials, we can synergistically reduce the work function and introduce the confinement effect, thus significantly enhancing the anode materials' electrochemical performance in LIBs.     

Steel slag quality control for road construction aggregates and its environmental impact: case study of Vietnamese steel industry—leaching of heavy metals from steel-making slag

Environmental Science and Pollution Research - Steel slag is an industrial by product of steel manufacturing processes and has been widely utilized within civil and construction materials for road...     

Predictions for isomer distributions of toxic dioxins and furans in selected industrial combustion processes

Three thermodynamic databases of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) have been used to simulate the PCDD/F isomer distribution in industrial combustion processes. The three databases had been derived using the Group Additivity approach and two computational molecular modelling methods, Modified Neglect of Diatomic Overlap (MNDO) and Parametrized Model 3 (PM3), respectively. The predictions of the toxic PCDD/F isomer distributions using the three different databases have been compared with measured values from industrial processes. An excellent agreement between the predictions using the MNDO method and the measured data has been obtained. It is concluded that the PCDD/F isomer distributions within each group observed in these combustion processes may be thermodynamically controlled.     

页岩-钢渣组合填料湿地强化脱氮除磷研究

以城市污水A/O工艺出水为处理对象,运用页岩和钢渣物化除磷、调控进水碳氮比和氮素氧化性等技术手段,在中试规模上研究了页岩和钢渣组合填料湿地的脱氮除磷效能及影响因素.结果表明,当COD面积负荷率、TN面积负荷率、TP面积负荷率、HRT(水力停留时间)分别为6.5～20.7 g·(m²·d)^-1、2.57～8.22 g·(m²·d)^-1、0.41～1.32 g·(m²·d)^-1、0.5～1.6d时,①氨氮、亚硝态氮和硝态氮的去除率分别为85.8%、56.3%和18.6%,TN去除率为58.0%,TN面积负荷去除率为3.58g·(m²·d)^-1,TN反应动力学常数为0.31 m·d^-1,TN面积负荷去除率随进水TN负荷的增加而线性增加.②TP去除率为90.4%,TP面积负荷去除率为0.89 g·(m²·d)^-1,TP反应动力学常数为0.86 m.d^-1,TP面积负荷去除率随进水TP负荷的增加而线性增加.③水温、HRT、氮素组分、C/N等因素对湿地系统的脱氮除磷效率有显著影响.TN面积负荷去除率随HRT、COD/TN值的增加而幂函数增加.TN面积负荷去除率随水温(、NO₂^--N+NO₃^--N)/TN值的增加而呈指数函数增加.     

ZT15型矿用火箭弹处理 尖山铁矿2号溜井堵塞

在处理该矿溜井堵塞中,在常规方法无效的情况下改用ZT型矿用火箭弹进行处理,获得成功。较详细介绍了该弹的使用方法、主要技术参数和特点。     

如何编写环境影响报告书的总量控制篇章

总量控制是建设项目环境影响报告书的重要部分，但在实际编写过程中面临着一定的困难。本文针对实际工作中的问题，归纳，明确了总量控制的几个概念，对总量控制篇章的编写要点进行了探讨，并提出了相应的建议。     

上海崇明岛近三年PM_(2.5)浓度变化特征与气象条件的关系

利用2011年1月~2014年2月上海崇明岛地区颗粒物(PM_(2.5)、PM_(10))的连续监测资料,研究了PM_(2.5)总体分布、季节变化、日变化及浓度频率分布规律,初步分析了逆温、相对湿度、风向风速等气象要素对颗粒物浓度的影响。结果表明:2011~2013年该地区PM_(2.5)平均值分别为24.7,33.6和28.3μg/m~3,均低于PM2.5的年平均浓度限值35μg/m~3,细粒子污染程度较轻。PM_(2.5)浓度日变化幅度不大,呈微弱的单峰型分布,9∶00左右达到一天中的最大值,15∶00左右达到最小值。PM_(2.5)浓度的季节分布特征明显,呈现出冬季春季秋季夏季,一般情况下5月份PM_(2.5)月均浓度值最高,8月份浓度最低。PM_(2.5)日平均浓度有57.9%达到国家空气质量一级标准,有93.4%达到国家空气质量二级标准,超标率为6.6%。对PM_(2.5)与各气象要素进行分析后发现:PM_(2.5)质量浓度在逆温层结稳定、风速小、高湿以及近地面盛行西北到西风这样的静稳天气条件配合高空西北方向上的外来污染物输送,容易造成高浓度的PM_(2.5)污染。     

一次强沙尘暴事件路径后向追源的数值模拟研究

沙尘暴源地的确定技术,一直是沙尘暴空气浮尘浓度场长距离输送数值模拟的最困难的科学问题之一。传统方法通常是使用降尘区的采集样本进行化学成分分析来确定。然而,采样误差和化学成分在大气长距离输送过程中的不确定性,也使得这种方法的可操作性不强。本文使用拉格朗日后向追踪数值模拟的新方法,依据中国气象局(CMA)的气象观测数据及其预报资料对一次沙尘暴事件进行了数值模拟,结果表明∶2003年4月9日的沙尘暴的主要源地来源于吉尔班通古特沙漠。