Energy implications of mechanical and mechanical–biological treatment compared to direct waste-to-energy

Primary energy savings potential is used to compare five residual municipal solid waste treatment systems, including configurations with mechanical (MT) and mechanical–biological (MBT) pre-treatment, which produce waste-derived fuels (RDF and SRF), biogas and/or recover additional materials for recycling, alongside a system based on conventional mass burn waste-to-energy and ash treatment. To examine the magnitude of potential savings we consider two energy efficiency levels (state-of-the-art and best available technology), the inclusion/exclusion of heat recovery (CHP vs. PP) and three different background end-use energy production systems (coal condensing electricity and natural gas heat, Nordic electricity mix and natural gas heat, and coal CHP energy quality allocation).The systems achieved net primary energy savings in a range between 34 and 140 MJ_primary/100 MJ_{input waste}, in the different scenario settings. The energy footprint of transportation needs, pre-treatment and reprocessing of recyclable materials was 3–9.5%, 1–18% and 1–8% respectively, relative to total energy savings. Mass combustion WtE achieved the highest savings in scenarios with CHP production, nonetheless, MBT-based systems had similarly high performance if SRF streams were co-combusted with coal. When RDF and SRF was only used in dedicated WtE plants, MBT-based systems totalled lower savings due to inherent system losses and additional energy costs. In scenarios without heat recovery, the biodrying MBS-based system achieved the highest savings, on the condition of SRF co-combustion. As a sensitivity scenario, alternative utilisation of SRF in cement kilns was modelled. It supported similar or higher net savings for all pre-treatment systems compared to mass combustion WtE, except when WtE CHP was possible in the first two background energy scenarios. Recovery of plastics for recycling before energy recovery increased net energy savings in most scenario variations, over those of full stream combustion. Sensitivity to assumptions regarding virgin plastic substitution was tested and was found to mostly favour plastic recovery.     

中国电子废物回收处理体系的生态效率分析

应用生态效率分析方法,以废弃台式电脑电源为例,对电子废物回收处理体系的2种不同策略进行模拟与比较,以探索适合我国国情的电子废物回收处理模式。其中环境效应的评价采用生命周期评价方法,经济价值采用生命周期成本分析方法。结果表明,以人力收集与人工拆解、元件再利用为特点的电子废物回收处理策略的生态效率要优于以机动车辆运输与破碎、分选处理相结合的策略。从生命周期阶段看,人力收集运输相比机动车辆收集运输模式,并不存在明显优势。但在处理处置阶段,人工拆解与元件再利用的模式生态效率更高。综合考虑,建议在收集运输阶段应鼓励发展高效合理的机动车辆收集运输模式,在处理处置阶段应更多支持人工拆解与元件再利用的模式。     

二元水循环模式下的水生态系统服务功能评价

在强人类活动干预下，流域水循环越来越呈现出“自然-人工”二元驱动结构，相应的水生态系统服务功能也呈现出明显的二元特征，这对其驱动机制和定量评价研究提出新的挑战。在深入分析流域二元水循环及水生态系统服务功能内涵的基础上，综合国内外研究现状，分析了当前研究中存在的不足；分析了自然水循环及其伴生过程和社会水循环过程对水生态系统服务功能的驱动机制，提出基于单过程单目标的四边形计算模式；基于二元水循环的多过程间多向反馈特征对水生态系统服务功能的交叉影响，构建了适用于河流、水库以及湿地等不同类型的水生态系统服务功能二元水循环评估指标体系；结合当前研究中存在的问题，提出需重点加强水生态系统服务功能评价方法以及驱动因子等方面的基础研究。     

北京市生活垃圾处理的环境影响评价

目前北京市生活垃圾产生量不断增加,处理设施能力日渐不足,生活垃圾管理正面临着减量化与资源化必然趋势。在未来5～10年内,堆肥处理、焚烧处理和综合处理等方式将取代卫生填埋成为北京市垃圾处理的主要方式。本研究采用生命周期评价的方法,对北京市4处垃圾处理设施采用的不同工艺（卫生填埋、好氧堆肥、焚烧处理和综合处理）的环境影响进行比较。评价结果表明4,种处理方式中填埋、堆肥、焚烧和综合处理的环境影响负荷分别为4.82×10-2、1.10×10-21、.31×10-1和2.31×10-2,焚烧处理的总环境影响潜值最大,填埋处理次之,综合处理再次,堆肥处理最小。4种处理方式的资源耗竭系数分别为-2.39×10-51、.11×10-5、-3.45×10-4和-1.04×10-6,焚烧处理的资源耗竭系数最小。     

Methodology of CO2 emission evaluation in the life cycle of office building façades

The construction industry is one of the greatest sources of pollution because of the high level of energy consumption during its life cycle. In addition to using energy while constructing a building, several systems also use power while the building is operating, especially the air-conditioning system. Energy consumption for this system is related, among other issues, to external air temperature and the required internal temperature of the building. The façades are elements which present the highest level of ambient heat transfer from the outside to the inside of tall buildings. Thus, the type of façade has an influence on energy consumption during the building life cycle and, consequently, contributes to buildings' CO₂ emissions, because these emissions are directly connected to energy consumption. Therefore, the aim is to help develop a methodology for evaluating CO₂ emissions generated during the life cycle of office building façades. The results, based on the parameters used in this study, show that façades using structural glazing and uncolored glass emit the most CO₂ throughout their life cycle, followed by brick façades covered with compound aluminum panels or ACM (Aluminum Composite Material), façades using structural glazing and reflective glass and brick façades with plaster coating. On the other hand, the typology of façade that emits less CO₂ is brickwork and mortar because its thermal barrier is better than structural glazing façade and materials used to produce this façade are better than brickwork and ACM. Finally, an uncertainty analysis was conducted to verify the accuracy of the results attained.     

户用沼气模式生命周期减排清单与环境效益分析

相对于传统农业活动,以沼气为纽带的生态农业生产具有清洁的能源生产和高度闭环的废物回收处置等明显优势,在全国范围内得到入户推广。本文综合考虑沼气工程建造、使用和综合利用等生命周期过程,分析了典型户用沼气池综合利用各阶段环境节能减排清单,并在此基础上评价其环境效益。结果表明,"猪-沼-稻-果"综合农业利用模式下单位沼气池节能减排效果明显,其中CO2、PM10、CH4和CO净减排量分别达3 060.700kg、19.820kg、12.960kg和75.590kg,总净节能达9 068.4MJ。其中,玉米秸秆、沼液沼渣的利用和燃煤替代对温室效应的减缓明显,畜禽粪便的利用和燃煤的替代减缓了环境酸化以及富营养化过程,而光化学氧化的减缓主要来自玉米秸秆的利用而减少的CO、VOC的排放,沼气工程对人体毒害的减缓主要是来自燃煤替代而减少的SO2和PM10排放。户用沼气利用对各种环境影响均有减缓作用,其中对光化学氧化、富营养化、环境酸化和温室效应的改善最为显著,对于降低能源耗竭、减缓对人体的毒性也起到了较好的作用。     

基于标签生命周期的射频识别系统安全和隐私风险研究

针对无线射频识别(RFID)技术应用的日益重要性和RFID系统的安全性现状,基于RFID技术机理,从安全和隐私风险的角度阐述RFID技术及其应用业务进程,并分析RFID技术所面临的主要安全和隐私危险问题。在此基础上,基于标签生命周期(RTLC)方法,详细分析标签在使用过程中所存在的安全漏洞和威胁性,信息资产的完整性和可用性,以及隐私情况。然后从实际应用的角度提出减轻安全和隐私风险的具体措施,以期为解决RFID应用中存在的各种安全和隐私问题提供帮助。分析表明,采用RTLC方法,并根据业务进程的不同阶段采取相应的安全措施可以降低或缓解RFID系统的安全和隐私风险。     

Effects of estrogen exposure in mussels, Mytilus edulis, at different stages of gametogenesis

Mytilus edulis were exposed to 17β-estradiol (E2) and the synthetic estrogens ethinyl estradiol (EE2) and estradiol benzoate (EB) for 10 days. Two exposures were performed to determine their effect on vitellogenin (VTG) and estrogen receptor 2 (ER2) mRNA expression at different stages of the reproductive cycle. Significant natural variation was not observed in VTG mRNA expression, though ER2 mRNA expression displayed significantly lower values during January, February and July compared with other times of the year. A significant increase in VTG and ER2 mRNA expression was observed in mussels exposed to estrogens at the early stage of gametogenesis. In contrast, mature mussels displayed no statistically significant change in the VTG or ER2 mRNA expression. The data presented suggests that the reproductive physiology of molluscs, in terms of VTG and ER2 mRNA expression, may be susceptible to damage by environmental estrogens at certain points in their gametogenesis process.     

Emission Inventories of Carbon-containing Greenhouse Gases in China and Technological Measures for Their Abatement

Abstract

The report summarizes surveys on carbon inventories and initiatives on sustainable carbon cycling taken by the Research Center for Eco-Environmental Sciences, where the authors work/worked. The first part of the report, which appeared in the preceding issue of this journal, deals with the concept of sustainable carbon cycling, the historic evolution of carbon cycling processes in China, carbon pool enhancement, value addition, carbon sequestration and carbon balance. This very paper, as the second part of the report, covers the results of carbon dynamics modeling, emission inventories of various carbon-containing greenhouse gases and their potential abatement measures.     

原尾蜥虎(Hemidactylus bowringii)雄性生殖周期的研究

对福州产的原尾蜥虎（Ｈｅｍｉｄａｃｔｙｌｕｓｂｏｗｒｉｎｇｉｉ） 雄性生殖周期的研究结果表明：１０ 月份精子发生开始新的周期性复生，精原细胞发育进入增殖期，中旬曲细精管除精原细胞外尚有较多的初级精母细胞；１１ 月初已有较多的精细胞，曲细精管管腔中开始出现少量的精子；１２ 月份，生精活动非常活跃，输精管始见有成熟的精子，１２ 月下旬进入冬眠期，成熟的精子释放到输精管中过冬，冬眠期间生精活动趋于停滞，表现为曲细精管管径和生精上皮厚度都有所下降；次年３ 月底４ 月初陆续出蛰，生精活动又恢复并逐渐增强，４、５ 月份精子发生相当活跃，６ 月份是精子发生的高峰期，也是交配繁殖的高峰期；原尾蜥虎一年只繁殖一次，繁殖期过后，７ ～９ 月份，生精活动逐渐减弱，曲细精管的管腔逐渐消失，初级、次级精母细胞、精细胞逐渐减少、退化，精子逐渐退化、消失，到９ 月下旬曲细精管和输精管都见不到精子，此时的曲细精管主要由精原细胞组成，一个周期到此结束．