Memory effect on the dioxin emissions from municipal waste incinerator in Taiwan

Evaluation of the dioxin removal efficiency of the air pollution control device (APCD) at an existing municipal waste incinerator (MWI) located in Taiwan is conducted via stack sampling and analysis. The MWI investigated is equipped with cyclones, dry lime scrubbing systems and fabric filters as APCDs. Results indicate that the patterns of dioxin isomers at APCDs' inlet and stack are similar. During the first year of carbon injection, the concentrations of emitted dioxin decreased greatly. The dioxin removal efficiency increased from 26.9% to 96.6% after injecting 115 kg/day activated carbon (AC). At the second year, the dioxin removal efficiency reaches 98.7% after injecting the same rate of AC continuously. The lower efficiency achieved with activated carbon injection (ACI) during the first year can be attributed to the memory effect, i.e. the dioxin or precursor desorbs slowly to the flue gas and increases the dioxin concentration at stack, resulting in a lower dioxin removal efficiency than expected.     

城市生活垃圾焚烧炉渣工程性质研究

本实验研究了上海市××垃圾焚烧发电厂炉渣工程性质,测试了原状炉渣及经几种规格方孔筛过筛后炉渣的粒径分布、物理组分、有机质含量、含水率、密度、吸水率和坚固性等指标。实验结果显示 :原状炉渣粒径分布均匀,含有一些大颗粒,物理组分复杂、强度高、坚固性好 ;与天然石料相比,含水率和吸水率高、密度小 ;过筛后炉渣的工程性质优于原状炉渣。同时讨论了生活垃圾焚烧炉渣用作公路基层集料的技术可行性,确定采用 2 6 5mm方孔筛过筛可以作为炉渣用作公路基层集料时的一种预处理方法     

Metal binding capacity of soft acid,organic‐rich waters

Organic carbon from one stream and two ponds in South Carolina was fractionated into five nominal molecular diameter fractions by ultrafiltration. The concentrations associated with and binding capacity for Ca, Cd, Cu and Pb were determined for each fraction. The distribution of organic carbon among ultrafilter fractions varied from water to water, with the largest percentage occurring in the smaller fractions. Calcium was associated with each of the fractions isolated from each of the three waters, indicating Ca is bound to organics in all fractions, however, more than 99% of the Ca which passed the smallest ultrafilter was removed by cationic exchange resin. Each fraction bound more Ca than Cd, Cu or Pb except in a few cases where Pb binding was greater. All of the organic fractions had their Ca++ binding sites saturated. Calcium was not an effective competitive ion against Cd, Cu or Pb for organic binding sites. The total Cu binding capacity was less than that of Ca or Pb but similar to that of Cd. Naturally occurring organics bound more Pb than Cd or Cu but less than Ca. Saturation of Cu binding sites was less than 20% in most ultrafilter fractions except that with a nominal molecular weight of between 10,000 and 300,000 where the percent of saturation was as much as 60%. Approximately 50% of the Cu was removed onto anionic exchange resin in two waters while more than 90% was removed from water with a high organic content. Percent saturation of Cd and Pb binding sites ranged from 0.091% to 5.4% and 0.059% to 1.5%, respectively. All ions tested effectively competed with Cd, Cu or Pb for some but not all binding sites, indicating that organic binding sites were heterogeneous. A generalized order of metal‐organic stabilities based on competition for binding sites is Al>Cd>Pb>Cu>Ni = Mg=Zn = Mn>Ca. Both Cd+2 and Al+3 effectively out competed Pb++ and Cd and Pb out competed Cu for most organic binding sites.     

Fates and partitioning of heavy metals in municipal solid waste incineration process

The fate and partitioning of heavy metals (including Hg, Cd, Pb, Zn, As, Cr, Ni, and Cu) from MSW incinerators located in Taiwan were determined. Results of stack sampling indicate that most Hg and As (more than 80%) exists in the gas phase while other metals partition differently among bottom ash, fly ash, and flue gases. Removal efficiencies of existing air pollution control devices for Hg and As are lower (about 70%) than other metals. Bottom ash contains higher concentration of Cd compared with European incinerators. In addition, strong enrichment of Cd on fly ash particles is observed.     

Possible Use of Ash Residues for the Construction of Artificial Reefs at Sea

Utilization of ash residues, including coal ash, oil ash, and municipal solid waste combustion ash, for the construction of artificial reefs at sea has been investigated by many researchers throughout the world for nearly 20 years. Both laboratory and field studies have shown that an artificial reef made of stabillized ash-concrete (SAC) has had no adverse effect on the marine environment. Indeed, published studies have shown that fish counts increase around SAC reefs owing to an abundance of colonizing organisms and to protection provided by cavities within the reef structures. However, public and regulatory resistance to the use of SAC for artificial reef construction at sea is still very strong in certain countries due to concern for possible negative environmental impacts, primarily in the area of bioaccumulation of elements or compounds originating from the ash component of SAC.

In this paper, technological feasibility of using ash residues for artificial reef construction is presented, based on the available 20 years of scientific data, including engineering workability, physical integrity, chemical leaching potential and biological effects. More important, we also identify conceptual barriers for the acceptance of using SAC for the construction of ocean reefs and suggest approaches to overcome these barriers.     

水泥窑共处置废白土的环境效益分析

以废白土为研究对象,应用生命周期评价法(LCA)对水泥窑共处置和焚烧炉处置系统3个类别的环境影响[人类健康(HH)、生态系统质量(EQ)和资源(R)]进行研究和对比分析.结果表明,水泥窑共处置废白土有利于环境的可持续发展,焚烧炉处置对环境的影响较大.水泥窑共处置和焚烧炉处置功能单位废白土的总环境负荷分别为-1.03,0.273Pt,前者的环境负荷比后者减少了477%,相应各指标的减少率为:HH 413%, EQ 479%, R 36.9%. EQ在2种处置方式的LCA中均为最敏感的影响指标.水泥窑系统中,避免了贡献率占97%以上的矿山开采阶段的环境影响,是降低整个系统环境影响的关键环节;焚烧炉系统中,电力消耗是造成环境破坏的重要阶段,对各影响指标都有很高的贡献率.二 、苯、重金属的排放是水泥窑共处置废白土的主要影响因子;粉尘和重金属排放对焚烧处置系统的影响较大.     

炉排型城市生活垃圾焚烧炉排气中二(口恶)(口英)污染状况及存在问题

选择四种规模不同的炉排型生活垃圾焚烧炉,分别对其排放烟气中的二(口恶)(口英)进行测定,从不同炉排型垃圾焚烧炉二(口恶)(口英)的排放现状并结合实际调查结果表明,不同炉型的生活垃圾焚烧炉存在一些共性问题,尚需加强垃圾焚烧的炉前、炉中及烟气处理各个环节的运行管理.     

医疗废物焚烧炉周边环境介质中二噁英的浓度、同系物分布与来源分析

采用高分辨气相色谱/高分辨质谱仪(HRGC/HRMS)测定了我国西北某医疗废物焚烧炉排放烟气及周边环境空气、土壤和植物样品中2,3,7,8-PCDD/Fs含量和组成,并对周边环境中二噁英来源进行了初步解析.监测结果表明烟气中二噁英毒性当量浓度(以I-TEQ计)均值为184 ng·m-3,远超医疗废物焚烧废气排放标准限值(0.5 ng·m-3),环境空气、土壤和植物样本中二噁英毒性当量浓度均值分别为7.30 pg·m-3、52.5 pg·g-1、146 pg·g-1,均处于较高的污染水平.污染源下风向上的环境空气样品中二噁英浓度明显高于上风向上样品中的浓度,下风向样品中的浓度随与污染源距离的增加呈现先升高后降低的趋势,最高浓度的样本距污染源700 m左右.烟气样品2,3,7,8-PCDD/Fs同类物单体质量浓度(毒性当量)分布特征与主导风下方向空气、土壤、植物样本中的具有较强的相似性.样本二噁英浓度空间分布特征、同类物分布特征及主成分分析数据均表明,该区域环境中二噁英主要来源于医疗废物焚烧烟气排放.     

北京市某垃圾焚烧厂周边大气二(口恶)英污染特征及暴露风险

2014年4月至2015年1月对北京市某生活垃圾焚烧发电厂周边6 km范围内7个采样点采集环境空气,应用高分辨气相色谱-高分辨质谱（HRGC-HRMS）联用技术对二英（PCDD/Fs）浓度水平进行监测并对其组成特征及时空特征进行了分析.结果表明该生活垃圾焚烧发电厂周边环境空气中PCDD/Fs质量浓度的变化范围为8.9~140 pg·m^-3,毒性当量（TEQ）变化范围为0.11~1.8 pg·m^-3,其中秋季霾天4个采样点和冬季全部采样点超出日本环境空气质量标准限值（TEQ：0.6 pg·m^-3）.1,2,3,4,6,7,8-HpCDF和OCDD是四季空气中PCDD/Fs质量浓度的主要贡献单体,年平均贡献率分别为20.5%和14.0%,而2,3,4,7,8-PeCDF是总TEQ贡献最大的单体,年平均贡献率为43.3%.空间分布特征表现为各采样点浓度水平与距污染源距离远近没有显著相关性;季节变化特征表现为冬季值显著高于其他季节,分析可能与冬季燃煤采暖及大气扩散条件差导致的大气颗粒物污染较重有关,与各季采样时段内大气PM₁₀和PM_2.5的平均浓度水平呈正相关相一致.样品中二英同族体及异构体分布指纹谱图与该焚烧设施排放烟气存在差别,主成分分析（PCA）源解析结论与指纹谱图特征分析结论一致.二英呼吸暴露剂量估算结果表明该区域人群呼吸暴露风险总体处于较为安全的水平[0.060~0.224 pg·（kg·d）^-1],但仍需关注大气颗粒物重污染天气发生时的呼吸暴露风险.     

浅谈石油化工废物的焚烧处理技术

介绍了焚烧系统在石化废物处理设计中的几个关键组成部分，并对常用的焚烧炉炉型的特点和适应性进行了分析。