Copper leaching of MSWI bottom ash co-disposed with refuse: Effect of short-term accelerated weathering

Co-disposal of refuse with municipal solid waste incinerator (MSWI) bottom ash (IBA) either multi-layered as landfill cover or mixed with refuse could pose additional risk to the environment because of enhanced leaching of heavy metals, especially Cu. This study applied short-term accelerated weathering to IBA, and monitored the mineralogical and chemical properties of IBA during the weathering process. Cu extractability of the weathered IBA was then evaluated using standard leaching protocols (i.e. SPLP and TCLP) and co-disposal leaching procedure. The results showed that weathering had little or no beneficial effect on Cu leaching in SPLP and TCLP, which can be explained by the adsorption and complexation of Cu with DOM. However, the Cu leaching of weathered IBA was reduced significantly when situated in fresh simulated landfill leachate. This was attributed to weakening Cu complexation with fulvic acid or hydrophilic fractions and/or intensifying Cu absorption to neoformed hydr(oxide) minerals in weathered IBA. The amount of total leaching Cu and Cu in free or labile complex fraction (the fraction with the highest mobility and bio-toxicity) of the 408-h weathered IBA were remarkably decreased by 86.3% and 97.6% in the 15-day co-disposal leaching test. Accelerated weathering of IBA may be an effective pretreatment method to decrease Cu leaching prior to its co-disposal with refuse.     

野鸭湖湿地挺水植物磷素截留量动态变化分析

野鸭湖湿地位于官厅水库上游,在截留养分、预防水库水体富营养化方面发挥着重要作用.通过野鸭湖湿地中4种优势挺水植物(茭白、扁秆藨草、香蒲、芦苇)的分布区域研究,分析了植物生物量及养分元素磷含量随季节的动态变化特征,得到了研究区域内4种挺水植物对磷素截留总量的动态变化.结果表明,研究区域内4种优势挺水植物地上部分磷含量为茭白>香蒲>扁秆藨草>芦苇;地下部分磷含量呈现茭白>扁秆藨草>香蒲>芦苇的分布特点;4种植物的地上部分和地下部分磷含量均随生长季节而降低;4种植物的单位面积磷素蓄积能力存在明显差异,表现为茭白>香蒲>扁秆藨草>芦苇的规律,其单位面积蓄积峰值依次为4910、4140、2190和1390g.m-2;研究区域内挺水植物磷素蓄积总量在夏季达到峰值2210.8kg,最小值出现在冬季,为1263.5kg;区域内上、中、下游挺水植物的磷素截留总量依次递减.     

“固化赤泥-人工膜”复合防渗材料研究

赤泥本身具有良好的防渗性能,加入石灰作为激发剂,更可提高其防渗性。根据《土工合成材料测试手册》和GB/T 50123—1999《土工试验方法标准》进行渗透试验,结果表明:室内试验在赤泥中加入8%石灰,并夹一层人工防渗膜形成的复合防渗材料,在固化28 d后,其渗透系数可达(7.3～7.4)×10-9 cm/s。在工业试验中,夹入不同厚度和质地的人工防渗膜的石灰(8%)固化赤泥,渗透系数可达到6.32×10-9～1.89×10-7 cm/s。研究成果在中原某铝厂赤泥堆场防渗工程中得到了应用。     

玻璃熔窑烟气脱硝技术探讨

结合玻璃熔窑烟气排放的特点,阐述了国内外玻璃熔窑烟气脱硝技术,湿法脱硝、选择性催化还原法(SCR)、选择性非催化还原法(SNCR)及其优缺点。探讨了SCR脱硝技术在玻璃熔窑烟气脱硝的运用,并给出了工程实例,最后提出了一些建议。     

2016~2018年采暖季太行山沿线城市PM2.5污染特征分析

对2016年、2017年采暖季太行山沿线传输通道城市大气中PM_2.5的OC、EC和水溶性离子进行分析,并利用特征组分比值和元素富集因子变化研究该传输通道的污染特征.结果表明,2017年采暖季通道整体较2016年同期空气质量改善良好,PM_2.5浓度由2016年的171.86μg/m³下降为123.90μg/m³.太行山中部城市2017年采暖季较2016年同期PM_2.5浓度下降显著,2a采暖季SNA离子（SO^2-,NO₃^-,NH₄⁺ 3种离子总称）浓度与占比呈现"北低南高",加之SNA/EC比值"北低南高",表明南部城市二次无机生成较为严重.而OC、EC浓度与占比呈现"北高南低",Cl^-/K⁺比值和元素Zn、Ba的富集因子北部均高于南部,表明北部城市可能受燃煤和机动车源等一次排放影响较大;各城市2017年采暖季SO₂、NO₂、CO浓度有所下降,且均呈现"北高南低"趋势,进一步表明北部城市一次排放较为严重.     

Temporal variability of visibility and its parameterizations in Ningbo, China

Simultaneous and continuous measurements of visibility, meteorological parameters and air pollutants were carried out at a suburban site in Ningbo from June 1, 2013 to May 31,2015. The characteristics of visibility and their relationships with air pollutants and meteorological factors were investigated using multiple statistical methods. Daily visibility ranged from 0.6 to 34.1 km, with a mean value of 11.8 km. During the 2-year experiment,43.4% of daily visibility was found to be less than 10.0 km and only 9.2% was greater than 20.0 km. Visibility was lower in winter with a frequency of 53.4% in the range of 0.0–5.0 km.Annual visibility had an obvious diurnal variation, with the lowest and highest visibility being 7.5 km at approximately 06:00 local time and 15.6 km at approximately 14:00 local time, respectively. Multiple correspondence analysis(MCA) indicated that the different ranges of visibility were significantly affected by different levels of pollutants and meteorological conditions. Based on the analyses, visibility was found to be an exponential function of PM_(2.5) concentrations within a certain range of relative humidity. Thus, nonlinear models combining multiple linear regressions with exponential regression were subsequently developed using the data collected from June 2014 to May 2015, and the data from June 2013 to May 2014 was used to evaluate the performance of the model. It was demonstrated that the derived models can quantitatively describe the relationships between visibility, air quality and meteorological parameters in Ningbo.     

黄土丘陵沟壑区生态风险时空动态及其风险分区—以陕西省米脂县为例

目前,黄土丘陵沟壑区等生态脆弱区生态风险评估已成为地理学与生态学应对生态系统管理的研究热点之一。以黄土丘陵沟壑区米脂县为研究区,构建“风险概率—敏感性—损失度”（PSI）的三维评价框架,并以子流域为评价单元进行数据整合,分析了米脂县2009-2015年准则层与综合生态风险的时空分异及其重心转移,并基于风险主导因子给出米脂县风险防范分区及降险对策。结果如下：（1）2009-2015年风险概率分别为49.93%、52.92%,有上升趋势;生境敏感性分别为0.61、0.60,下降了1.6%,生境质量趋好;损失度分别为0.42、0.46,损失度增加。（2）生态风险呈现中间高南北低的空间分布;研究期间生态风险值分别为0.14、0.15,风险有所升高;风险重心向西南转移跃入银州川道且风险演化主体方向为西北—东南走向。（3）风险预警区、生态恢复区、预警恢复兼顾区、自然调控区面积占比分别为7.53%、6.57%、23.86%、62.04%。基于风险主导因子的风险防范分区可有效进行风险消解,促进区域生境的可持续。     

硅铝比对分子筛吸附氨氮性能的影响

基于X射线荧光光谱法确定的4种ZSM5分子筛硅铝比,分析了不同硅铝比分子筛吸附氨氮性能的差异,结合扫描电镜、X射线衍射分析结果,从分子筛的骨架组成、表面形貌和晶体结构角度,考察了硅铝比对分子筛吸附氨氮性能的影响机制;并探讨了分子筛骨架脱硅对其吸附性能的改善作用,为分子筛应用于污水厂尾水深度脱氮提供技术参考.结果表明,不同硅铝比分子筛的表面形貌、晶体结构与吸附氨氮性能具有显著差异：随着分子筛硅铝比增加,其结晶度下降、晶粒形态逐渐模糊、吸附容量降低;当实际硅铝比由35增大至237时,氨氮平衡吸附量由5.65mg/g降至0.41mg/g,由Langmuir吸附等温式确定的饱和吸附量由6.5963mg/g下降至0.4430mg/g.分子筛吸附过程符合准二级动力学模型,吸附速率受离子交换化学吸附作用机理控制,随着硅铝比升高分子筛的离子交换容量下降,其吸附速率降低.分子筛骨架脱硅能够显著改善其氨氮吸附性能,硅铝比为35的分子筛经碱蚀脱硅处理后,其氨氮平衡吸附量提高81.6%,该方法为改善分子筛吸附性能提供了一种有效的技术途径.