Assessing the “design paradox” with life cycle assessment: A case study of a municipal solid waste incineration plant

One of the most important processes in an integrated waste management system is incineration, which, among the different waste management disposal options still remains a critical waste treatment system. New dynamics and approaches have to be developed to embrace such a wide and complex topic, and better knowledge and assessment of incineration are strategically significant to define future environmental scenarios.Life cycle assessment (LCA), as a tool to optimise process-operating conditions and to support decision-making process, is often applied to investigate processes under design in various sectors, since choices made in the development phases can affect the future environmental profile. However, even if the greatest opportunity to improve a process from an environmental perspective is during the design phase, at the same time the knowledge is limited, in accordance with the so-called “design paradox”.Thus, in this context, this study used LCA methodology to quantitatively assess the extent to which the environmental impact of an incineration line reflects the environmental burdens perceived during the design phase. A comparative LCA was conducted at the design phase and under operating conditions at an Italian municipal solid waste incineration plant.The outcomes of the study indicated that for almost all of the categories analysed, the impacts associated with the process under design overestimated the impacts associated with the operating process, with the exception of climate change and water depletion. The results suggested that after the conduction of an LCA at the design phase of a process, an LCA of the operative conditions should be carried out to verify how much the over- or under-estimations affected the results.     

固体添加剂对污泥焚烧过程中重金属迁移行为的影响

利用高温固定管式炉研究了4种固体添加剂(CaO、Al2O3、粉煤灰和高岭土)对污泥焚烧过程中6种重金属(Pb、Cd、Cu、Cr、Ni、Zn)在底渣中的迁移行为与固化残留特征的影响.结果表明,污泥焚烧过程中4种固体添加剂(CaO、Al2O3、粉煤灰和高岭土)的加入有利于重金属固定并且残留在焚烧底渣中,并且随着固体添加剂添加比例的增多,重金属的残留率也逐渐增加.焚烧温度对固体添加剂吸附重金属的效果有很大影响,其中重金属自身熔点、沸点及重金属在污泥中的赋存形态是决定其挥发性的一个重要因素.不同固体添加剂对不同重金属迁移的抑制效果有很大差异,从控制重金属挥发角度来看,固体添加剂高岭土和CaO要优于其他固体添加剂.固体添加剂活性中心与重金属化合物分子的相互作用取决于这些活性位的分布及重金属的化学性质.     

The potential contribution of sustainable waste management to energy use and greenhouse gas emission reduction in the Netherlands

Future limitations on the availability of selected resources stress the need for increased material efficiency. In addition, in a climate-constrained world the impact of resource use on greenhouse gas emissions should be minimized. Waste management is key to achieve sustainable resource management. Ways to use resources more efficiently include prevention of waste, reuse of products and materials, and recycling of materials, while incineration and anaerobic digestion may recover part of the embodied energy of materials. This study used iWaste, a simulation model, to investigate the extent to which savings in energy consumption and CO₂ emissions can be achieved in the Netherlands through recycling of waste streams versus waste incineration, and to assess the extent to which this potential is reflected in the LAP2 (currently initiated policy). Three waste streams (i.e. household waste, bulky household waste, and construction and demolition waste) and three scenarios compare current policy to scenarios that focus on high-quality recycling (Recycling+) or incineration with increased efficiency (Incineration+). The results show that aiming for more and high-quality recycling can result in emission reductions of 2.3 MtCO₂ annually in the Netherlands compared to the reference situation in 2008. The main contributors to this reduction potential are found in optimizing the recycling of plastics (PET, PE and PP), textiles, paper, and organic waste. A scenario assuming a higher energy conversion efficiency of the incinerator treating the residual waste stream, achieves an emission reduction equivalent to only one third (0.7 MtCO₂/year) of the reduction achieved in the Recycling+ scenario. Furthermore, the results of the study show that currently initiated policy only partially realizes the full potential identified. A focus on highest quality use of recovered materials is essential to realize the full potential energy and CO₂ emission reduction identified for the Netherlands. Detailed economic and technical analyses of high quality recycling are recommended to further evaluate viable integrated waste management policies.     

废液焚烧处置控制系统的设计

介绍并分析了针对废液焚烧处置进行的控制系统（PID）的构成、设计和应用;结合焚烧处置系统的流程及技术要点,通过合理的设计,实现了稳定且功能全面的焚烧装置控制系统。     

石化废水污泥实用焚烧处置技术

介绍了石化废水污泥焚烧处理的工艺流程、主要影响因素,分析了该项技术的优缺点。     

青岛市剩余污泥处置现状分析及资源化利用

介绍了青岛市城市污水处理厂剩余污泥目前的产生情况及处置现状,对比分析了国内外先进的剩余污泥处置方法和技术。提出了适合青岛市剩余污泥资源化利用的途径和方法。剩余污泥既是污染物又是一种资源,污泥的处理、处置与资源化利用相结合才是其最好的出路。     

常州酸焦油的无害化焚烧处理方法探索

以一种典型的液态危险废弃物--常州酸焦油为研究对象,添加一定比例的电石渣混合以后,通过管式炉不同工况下的焚烧实验来研究烟气中污染物的排放特性.实验结果表明,二氧化硫的排放受焚烧温度影响很大,700℃以下未能检测到有SO2析出,800℃以上硫转化率曲线呈快速上升趋势,900℃时物料中约1/5的硫转化为气态,至1000%时,有一半的硫转化为气态.同时,增大空气流量会对SO2排放产生一定的正面影响.     

AHP法在医疗废物处置技术综合评价中的应用

为选择医疗废物安全处置技术方案,文章以杭州地区医疗废物安全处置技术为例,建立技术评价程序。采用层次分析法(AHP)尝试建立一个4层13指标4方案模型,从经济指标、环境指标、技术指标等角度对焚烧法、高温高压灭菌法、机械-化学消毒法和微波处理法等4种技术进行综合评价。计算结果表明焚烧法的权值最大,是医疗废物处置技术方案的首选;层次分析法可提供更为直观的医疗废物处置技术方案的选择信息,研究结果对医疗废物安全处置全过程管理有一定的参考价值。     

Influence of chlorine on methane oxidation

Experiments on CH4/Cl2/O2/N2 oxidation were conducted in an atmospheric pressure flow reactor to understand the influence of chlorine on hydrocarbon oxidation in hazardous waste incineration. The reaction temperature varied from 973 to 1273 K and the chlorine to hydrogen mole ratio (Cl/H) of the inlet mixture varied from 0 to 0.44. The species produced in the reaction were measured online with Fourier transform infrared spectroscopy (FT-IR). It was found that the destruction and removal e ciency of CH4 increased with Cl/H mole ratio. Increasing Cl/H favored COCl2 and CO formation and inhibited the CO oxidation process. As Cl/H approached 0.44, the concentrations of CH2Cl2 and CH3Cl first increased, and then declined. Reaction temperature greatly a ected the reaction system. Increasing temperatures raised the destruction removal e ciency of CH4 and decreased the concentrations of CH3Cl and CH2Cl2. With a certain ratio of Cl/H, the concentrations of CO and COCl2 first increased and then declined. The CO and COCl2 concentration peak was observed around 1100 K and 1023 K, respectively. When the reaction temperature exceeded 1273 K, carbon in CH4 was mostly converted to CO2. It could be concluded that the presence of chlorine enhanced the destruction of CH4, but resulted in the more toxic incomplete combustion products emission such as COCl2 when the reaction temperature was not high enough.     

不同垃圾焚烧设备中二英的排放特征和I-TEQ指示物的研究

分析了国内3种不同类型的垃圾焚烧设备中二英化合物的排放特征,不同PCDD/F单体与I-TEQ的相关性以及23478-PeCDF与I-TEQ的线性回归分析.得到了不同类型的垃圾焚烧设备中二英同系物的统计学分布特征.结果发现,生活垃圾、医疗垃圾和危废焚烧炉中二英（PCDD/F）同系物分布虽有一定差异,但变化不大,与生活垃圾焚烧炉和危废焚烧炉相比,医疗垃圾焚烧炉中二英同系物的分布稍有区别.在3种焚烧炉的烟道气中体积分数最大的是OCDD和1234678-HpCDF,分别为12.3％～23.0％和15.0％～19.7％;而对I-TEQ贡献最大的则是23478-PeCDF,体积分数为33.1％～34.5％,远远高于其它的PCDD/F单体.通过对不同的PCDD/F单体与I-TEQ的相关性分析发现：23478-PeCDF与I-TEQ的相关性最好,相关系数R²为0.93～0.98;而毒性最大的2378-TCDD与I-TEQ的相关性较差,R²为0.29～0.49;体积分数最大的OCDD与I-TEQ的相关性很差,R²为0.03～0.12;体积分数较大的1234678-HpCDF与I-TEQ也有较好的相关性,R²为0.62～0.87,但依然次于23478-PeCDF.通过23478-PeCDF与I-TEQ线性回归的结果发现：即使I-TEQ的浓度范围为5～6个数量级,23478-PeCDF与I-TEQ也表现出很好的线性关系,对于不同的垃圾焚烧设备,回归曲线斜率为在1.16～1.40之间,相关系数R²在0.94～0.97之间.