Continuous CO2 capture and MSWI fly ash stabilization, utilizing novel dynamic equipment

Novel dynamic equipment with gas in and out continuously was developed to study the capture capacity of CO₂. Municipal solid waste incineration (MSWI) fly ash has a high capture rate of CO₂ in CO₂-rich gas. Fly ash can sequester pure CO₂ rapidly, and its capacity is 16.3 g CO₂/100 g fly ash with no water added and 21.4 g CO₂/100 g fly ash with 20% water added. For simulated incineration gas containing 12% CO₂, the capture rate decreased and the capacity was 13.2 g CO₂/100 g fly ash with no water added and 18.5 g CO₂/100 g fly ash with 20% water added. After accelerated carbonation, the C and O contents increased, indicating CO₂ capture in the fly ash; CO₂ combines with Ca(OH)₂ to form CaCO₃, which increased the CaCO₃ content from 12.5 to 54.3%. The leaching of Pb markedly decreased from 24.48 to 0.111 mg/L.     

Effective rates of heavy metal release from alkaline wastes--quantified by column outflow experiments and inverse simulations

Column outflow experiments operated at steady state flow conditions do not allow the identification of rate limited release processes. This requires an alternative experimental methodology. In this study, the aim was to apply such a methodology in order to identify and quantify effective release rates of heavy metals from granular wastes. Column experiments were conducted with demolition waste and municipal waste incineration (MSWI) bottom ash using different flow velocities and multiple flow interruptions. The effluent was analyzed for heavy metals, DOC, electrical conductivity and pH. The breakthrough-curves were inversely modeled with a numerical code based on the advection–dispersion equation with first order mass-transfer and nonlinear interaction terms. Chromium, Copper, Nickel and Arsenic are usually released under non-equilibrium conditions. DOC might play a role as carrier for those trace metals. By inverse simulations, generally good model fits are derived. Although some parameters are correlated and some model deficiencies can be revealed, we are able to deduce physically reasonable release-mass-transfer time scales. Applying forward simulations, the parameter space with equifinal parameter sets was delineated. The results demonstrate that the presented experimental design is capable of identifying and quantifying non-equilibrium conditions. They show also that the possibility of rate limited release must not be neglected in release and transport studies involving inorganic contaminants.     

生活垃圾焚烧飞灰加速碳酸化深度除氯与水洗除氯对比研究

选取了国内两个典型垃圾焚烧厂飞灰,在对飞灰基本理化特性进行分析的基础上,对比了水洗、加气水洗（通CO₂）、加气水洗+加碳酸盐水洗3种预处理方法的脱氯效果.结果表明,2种飞灰中氯含量均较高,分别达16.95%和20.52%.水洗预处理后氯的最高去除率分别达87.54%和90.12%.升高水洗温度对氯的去除贡献不明显.加气水洗可显著提高氯的去除率,2种飞灰氯的去除率分别达93.69%和99.19%,脱氯效果明显高于水洗脱氯.加气水洗虽提高了氯盐的去除率,但液相中依然残留有高浓度钙离子.在加气水洗的基础上,向反应体系中加入碳酸盐,可有效降低溶解性钙离子含量.通过对预处理飞灰进行XRD矿物相分析,发现加气碳酸化水洗较纯水洗过程去除了更多的难溶性氯盐,且处理后飞灰组分以碳酸钙和硫酸钙为主.采用《水泥化学分析方法（GB/T176-2017）》对加气水洗后飞灰进行测定,其氯含量低于1%,满足《生活垃圾焚烧飞灰污染控制技术规范（HJ1134-2020）》中资源化利用标准.     

添加剂对垃圾焚烧飞灰熔融特性的影响

研究制备了1种具有多重作用效果的飞灰熔融复合型添加剂,并选用上海和福州2种典型飞灰,利用荧光光谱仪和电感耦合等离子体质谱仪等仪器,分析了添加剂对飞灰熔融过程中的挥发率,流动温度,重金属固定率以及熔融渣的重金属浸出特性的影响.结果表明,添加10%添加剂可以将飞灰的流动温度降低150℃左右,挥发率降低10%～20%,重金属Cu和Pb的固定率提高了10%～20%,对重金属Zn的固定率可提高近40%;同时,采用我国毒性浸出方法和美国EPA的TCLP方法,分析测试熔融渣中重金属浸出量,结果证实几种重金属的浸出浓度均低于相应的标准限值.     

利用层次分析法探讨生活垃圾焚烧设施二噁英类排放的影响因素

基于焚烧过程中二噁英类(PCDD/Fs)的生成机理,深入探讨生活垃圾焚烧设施二噁英类生成及排放的诸多影响因素,并依据层次分析法(AHP)原理,从焚烧设施的技术水平、运行状况、管理水平3个影响因素着手建立递阶层次结构模型.分别对模型中的各个影响因素进行定性和半定量化处理,最终实现对生活垃圾焚烧设施二噁英类生成及排放影响因...     

湿法预处理对垃圾焚烧飞灰中重金属的形态及风险影响研究

以某典型城市生活垃圾焚烧飞灰为研究对象,采用X射线荧光光谱仪（XRF）、X射线衍射仪（XRD）和电感耦合等离子体光谱仪（ICP）测定了焚烧飞灰的主要成分、矿物学组成和重金属含量,探讨了湿法预处理工艺对飞灰的化学组成、矿物学形态、化学形态及风险水平的影响.结果表明,飞灰的主要化学组成为O、Ca、Cl、Na、K等,占飞灰总质量的93.54％,其次含有0.04％ ～0.68％的Zn、Pb、Cu、Cr等微量重金属元素;经过湿法预处理,飞灰中可溶性氯盐具有较好的去除效果,且几乎所有重金属元素的不稳定形态（弱酸提取态和可还原态）比例都有一定程度的减少,有效降低了重金属的毒性、生物有效性及环境风险水平.本研究有助于降低焚烧飞灰的环境风险和探寻其资源化的有效途径.     

添加垃圾焚烧飞灰冷固小球的工业烧结实验

将垃圾焚烧飞灰添加进烧结冷固球团配料进行造球,对冷固小球的成分及强度进行分析,结果表明,添加垃圾焚烧飞灰冷固小球化学组成稳定,重金属浸出毒性远低于危险废物鉴别标准,落下强度较基准期略微降低,但符合运输、贮存的要求.并对添加了飞灰的冷固小球对其后续烧结、冶炼工序的影响进行分析,结果表明,用添加飞灰的冷固小球进行烧结所得烧结矿的转鼓强度、落下强度及常规化学成分较基准期没有太大变化,添加飞灰进行造球、烧结,对其后续冶炼工序的顺行几乎没有影响,所带来的额外的环境污染微乎其微.     

MSWI BA treated with Advanced Dry Recovery: a field scale study on materials’ leaching properties

In many European countries, the environmental properties of waste-derived aggregates are mostly assessed based on laboratory leaching tests such as the standardised percolation tests CEN/TS/14405, ISO/TS 21268-3, or DIN 19528. These tests are conducted under specified conditions, which are similar yet somewhat different from realistic field conditions. Therefore, this study aimed to investigate the leaching properties of ADR (Advanced Dry Recovery) recovered MSWI BA in the field in order to understand more about its environmental impacts in actual civil engineering structures. Two field scale studies (a lysimeter and a larger interim storage field study) were constructed and the leachate quality was investigated. These results were then complemented with the results of previously conducted laboratory leaching tests using a liquid to solid ratio (L kg^?1) comparison. The results demonstrated that the leaching behaviours of many potentially harmful substances, such as chloride, copper and antimony, was similar despite the study scale. In addition, this study illustrated the importance of investigating the leaching properties of waste-derived aggregates on a larger scale, even though the uncertainties in such studies may not be easily controlled.     

Recovery of copper from small grain size fractions of municipal solid waste incineration bottom ash by means of density separation

Small grain size fractions of municipal solid waste incineration (MSWI) bottom ash (BA) contain elemental and chemically bonded metals in appreciable amounts, especially copper. Investigations with a centrifugal concentrator were carried out using samples, which had been treated with different impact devices. Partly the impacts of single devices were visible in outlines, but mostly the surfaces of the metals were still covered with mineral residues. To generate copper rich fractions, parameters of the separation process should ensure mass yields <2%, best between 0.5 and 1%. The density of the concentrates is then generally >3.2 g/cm³. Best results were achieved with material from a special treatment train which is adapted to grain sizes <2 mm. Reliable copper contents between 20 and 40% (single runs >50%) could be realised. However, considering the required mass yields, referred to this subset only 150–170 g copper would be recovered from 1 Mg MSWI BA. Furthermore, this copper is only in parts present in elemental form. A dependable added value of such treatment step seems to be given only, if that enables a recycling of the mineral aggregates (tailings) in parallel to avoid landfill costs.     

生活垃圾焚烧厂周边环境空气中PCDD/Fs含量及分布特征

对我国某工业区生活垃圾焚烧厂周边5km范围内14个采样点环境空气中四氯~八氯代二 英(2,3,7,8-PCDD/Fs)含量及其组成特征进行了分析.结果表明该垃圾焚烧厂周边环境空气PCDD/Fs浓度的变化范围为1.74~15.2pg/m3(0.156~1.44pg I-TEQ/m3),均值为4.60pg/m3(0.426pg I-TEQ/m3),其中3个点位接近或超出日本环境空气质量标准限值(0.6pg I-TEQ/m3),表明某些区域处于一个较高的污染水平;最大浓度点位于焚烧设施下风方向1.3km处,与AERMOD预测的最大落地浓度位置一致.1,2,3,4,6,7,8-HpCDF和OCDD是空气中二 英质量浓度主要贡献因子,而2,3,4,7,8-PeCDF是毒性当量浓度的主要贡献因子.样品中二 英同族物分布的指纹特征显示出可能受MSWI源影响点位与非MSWI影响(或受此源影响较小)点位的区别.主成分分析(PCA)源解析结论与空间分布以及指纹特征分析结论基本一致,且更具体地判断MSWI的影响点位,在一定程度上说明了此方法的可靠性.二 英呼吸暴露剂量估算结果表明该区域人群二 英呼吸暴露风险总体处于较为安全的水平.