生活垃圾焚烧飞灰固化体力学及重金属浸出特性

以苏州七子山生活垃圾焚烧厂产生的飞灰为研究对象,采用水泥作为固化剂,研究水泥飞灰固化体的应力应变特征及重金属浸出特性,并探讨了水泥飞灰配合比、养护时间等关键性因素对这些特性的影响。实验结果表明:较养护3 d的样品,其余养护时间的样品强度平均增长了约96.2%,而其破坏应变平均减小了56%。随着水泥含量和养护时间的增加,飞灰固化体的强度上升,而其破坏应变减小,该趋势主要归因于钙矾石(AFt)的形成促进了飞灰固化体强度的发展。较飞灰原样,飞灰固化体的重金属浸出浓度随着水泥含量、养护时间的增加而降低了38%~99%,重金属的迁移被限制,主要归因于水化硅酸钙(C—S—H)和钙矾石(AFt)的形成,以及飞灰和水泥水化反应创造的强碱性环境。     

污染场地固化/稳定化修复的评价方法与标准

固化/稳定化技术是一项在欧美等国家的污染场地修复中广泛应用的技术.在分析固化/稳定化修复效果常用的浸出试验方法和物理评价方法以及相对应的评价标准的基础上,发现我国固化/稳定化修复效果的评价方法仅有少量振荡浸出试验的方法,还缺少动态浸出试验的评价方法;浸出毒性测试普遍采用硫酸硝酸法浸出评估,忽略了As、Cr(Ⅵ)等含氧阴离子在中性至弱碱性pH下溶解度达到最大的情况;固化/稳定化修复效果的评价标准则主要借鉴固废毒性鉴别与管理方法,但该方法未规定污染土壤资源化再利用时的评价依据;另外,污染土壤和固体废物的自身特性也有一定的差异.提出了基于我国国情的污染土壤固化/稳定化浸出测试和评价标准体系:当污染土壤固化/稳定化后采用卫生填埋或一般工业固体废物贮存、处置场处置时,可参考固体废物填埋处置时的评价方法与标准;当污染土壤固化/稳定化后原址填埋时,则应增加绕流浸出方法或穿透浸出试验方法,其评价标准可参考GB/T 14848—1993《地下水质量标准》或根据关注点浓度的要求进行风险评估推算确定;当污染土壤固化/稳定化后再利用时,需根据再利用的具体情景选择相应的评价方法与标准.      

Assessment of nitrogen leaching from arable land in large river basins: Part II: regionalisation using fuzzy rule based modelling

This study deals with fuzzy rule based modelling of nitrogen (N)-leaching from arable land. Main purpose is the elaboration of a method, which allows dynamical regionalisation of results from process-based models for large regions and can be efficiently included in metamodels or decision support systems for rapid integrated assessment of water resources. The paper is the second part of a two-part paper. In the first paper the distributed ecohydrological model SWIM had been applied to calculate and analyse nitrogen dynamics in arable soils for a set of representative natural and management conditions in the Saale River basin (Ecol. Model. (in press)). Here, in the second paper the results from those simulation experiments are used to define, train and validate fuzzy rule systems for the estimation of N-leaching. Nine fuzzy rule systems, specific for nine soil classes, were created from the simulation experiments, representing the conditions for the whole Saale River basin. The fuzzy rule systems operate on monthly time steps and consist of 15 rules and seven input variables each, which are compiled from time series of precipitation, percolation and evapotranspiration as well as from information about fertilizer and crop specific nitrogen uptake. Simulated annealing as a non-linear discrete optimisation method is used for automatic rule assessment. Validation of the fuzzy rule systems, carried out by split sampling of 30-year simulation period, shows satisfactory performance on an annual basis and good performance on the long-term basis with average correlation between SWIM-simulated and fuzzy rule-estimated N-leaching values of 0.78 and 0.94, respectively.     

上海青紫泥土壤氮素淋溶及其对水环境影响研究

农田氮素淋失受多方面因素的影响，其淋失研究有多种方法，利用渗漏池，在上海青浦农田水利试验站进行青紫泥土壤氮素的淋溶模拟试验，以探讨不同水肥管理方式下的淹水稻田中，氮素的迁移，转化机制及其对水环境的影响，研究结果表明：淹水稻田中氮素淋失的基本形态为硝态氮（NO3^-,N)，在下渗水流的驱动下，NH4＋－N也能渗漏到一定的深度，对地下水环境形成威胁，但不如NO3－N显著；不同处理的剖面中NO3－－N和NH4＋－N浓度均表现出随深度增加逐渐降低的趋势，每次施肥后，不同处理剖面中的NO3＿N浓度均表现为短期内迅速上升，后期逐渐下降的趋势，其中NH4＋－N浓度与NO3－－N的消长规律相似，但表现出峰值超前且变幅远大于NO3－－N浓度的特征；氮素的淋失主要发生在当年的6－8月份之间，此期与降雨高频期的重叠加剧了对水环境的污染，采用节水节肥的管理模式，不仅能保护产量，还能减少灌溉量，大大降低施用氮肥对地下水污染的威胁。     

失效锂离子电池有机物真空脱除和浸出研究

文章采用真空蒸发热处理的方法脱除废弃失效的锂离子电池中的有机物,加热温度为220~500℃,真空炉内压力150Pa,恒温处理时间1h。除有机物被脱除外,当处理温度为280℃时形成了CoO和Li2CO3。温度升高至350℃时,主要的物相为LiCoO2、CoO、Co3O4和Co,以及少量Li2CO3。在超声场中将电极材料与铝、铜箔集流体分离,然后分别用含亚硫酸钠的硫酸溶液和氨性溶液处理电极材料。当用含亚硫酸钠的硫酸溶液浸出经280℃脱除有机物的电极材料时,钴元素基本被浸出。而用氨性溶液浸出经350℃脱除有机物的电极材料时,钴元素的浸出率很低。为了提高钴的浸出率,真空热处理的温度应介于280~350℃之间。     

GIS based ArcPRZM-3 model for bentazon leaching towards groundwater

Groundwater contamination due to pesticide applications on agricultural lands is of great environmental concern. The mathematical models help to understand the mechanism of pesticide leaching in soils towards groundwater. We developed a user-friendly model called ArcPRZM-3 by integrating widely used Pesticide Root Zone Model version 3 (PRZM-3) using Visual Basic and Geographic Information System (GIS) based Avenue programming. ArcPRZM-3 could be used to simulate pesticide leaching towards groundwater with user-friendly input interfaces coupled with databases of crops, soils and pesticides. The outputs from ArcPRZM-3 could be visualized in user-friendly formats of tables, charts and maps. In this study we evaluated ArcPRZM-3 model by simulating bentazon leaching in soil towards groundwater. ArcPRZM-3 was applied to 37 sites in Woodru County, Arkansas, USA to observe the daily average dissolved bentazon concentration for soybean, sorghum and rice at a depth of 1.8 m for a period of two years. Nineteen ranks of bentazon leaching potential were obtained using ArcPRZM-3 for all sites having di erent soil and crop combinations. ArcPRZM-3 simulation results for bentazon were compatible with the field monitored data in term of relative ranking and trend, although some uncertainties exist. This study indicated that macropore flow mechanism would be important in analyzing the e ect of irrigation on groundwater contamination due to pesticides. Overall, ArcPRZM-3 could be used to simulate pesticide leaching towards groundwater more e ciently and e ectively as compared to PRZM-3.     

高尔夫球场果岭土壤硝酸盐氮淋洗的模拟试验研究

通过对高尔夫球场施用化肥后的降雨过程进行模拟淋滤试验,测试了不同施肥量、降雨强度及植被密度条件下硝酸盐的淋失浓度,并借助SAS9．0软件对测试数据进行了统计分析。结果表明,在降雨总量相同的条件下,淋滤出的硝酸盐氮受植被密度和施肥量的影响较大,而降雨强度则元显著影响;在暴雨-稀草-高肥时的硝酸盐氮淋出量最多,而中雨-密草-低肥淋出量最少。土壤中硝酸盐氮含量与淋滤液中硝酸盐氮的淋失量规律吻合,即硝酸盐氮淋失量大时,土壤中的硝酸盐氮含量低;而硝酸盐氮淋失量小时,土壤中的硝酸盐氮含量高。     

城市生活垃圾的生物工程堆肥化利用

在建立节约型社会、发展循环经济时代,通过对城市生活垃圾3种处理方法的比较得出,以堆肥方式通过生物工程技术对城市生活垃圾进行科学合理处置,是达到城市生活垃圾无害化、资源化、减量化、规模化处理的最佳选择。     

无铅焊料合金中重金属元素浸出行为的研究

选用Sn.3.5Ag-0.5Cu、Sn-3.5Ag、Sn-0.5Cu无铅焊料合金及它们与Cu的钎焊接头,研究了它们在典型的酸性、碱性和盐溶液中的重金属元素的浸出规律.结果表明,焊料合金中的主要浸出元素Sn在酸性或碱性溶液中的浸出量都不是太多,而在NaCl盐溶液中浸出量增大2个数量级.制备成钎焊接头后,在酸性环境中,Sn-3.5Ag和Sn.0.5Cu钎焊接头中Sn的浸出量增加1个数量级以上,而在NaOH碱性环境中.Sn-3.5Ag-0.5Cu钎焊接头中Sn的浸出量相对较高.该结果对电子垃圾填埋环境选择及相关决策提供了参考.     

有机-无机肥配施对紫色土坡耕地氮素淋失的影响

通过坡地渗漏小区定位试验,研究总施氮量相同情况下,施肥方式对紫色土坡耕地氮素淋失的影响.结果表明,有机-无机肥配施会影响紫色土硝酸盐向下累积过程,显著降低紫色土坡耕地硝酸盐累积量.渗漏液中硝态氮含量在0.15～46.99mg·L-1之间,占总氮含量的66.4%～96.3%;总氮淋失量在(4.05±0.37)～(37.82±0.86)kg.hm-2之间,占当季施氮量的2.7%～25.2%.在维持总施氮量相同的条件下,与常规氮磷钾施肥相比,农家肥、秸秆与化肥配合施用的渗漏液总氮含量分别降低了71.0%、61.4%,总氮淋失量分别降低了48.1%、31.6%.这表明有机-无机肥配施能显著降低紫色土坡耕地氮素淋失量,对有效控制紫色土区浅层地下水硝酸盐污染具有重要作用.