Municipal solid waste conversion to energy

In recent years it has been recognised by an increasing number of nations that there is considerable energy potential within MSW. As a result many countries have established R,D& D programmes to examine methods of exploiting this potential. The IEA's MSW Conversion Activity was set up in 1986 to provide an infrastructure for sharing information and co-ordinating work in this area internationally. This Activity was extended in 1989 and currently a total of 9 nations participate in it.

To cope with the wide scope of the area (encompassing both biological and thermal processing of MSW) the Activity was divided into three subgroups or Expert Working Groups (EWGs). Each of these dealt with a distinct area of expertise:

1. •Downstream effects of source separation and screening of MSW

2. •Sampling and analytical protocols

3. •Landfill gas

In addition to these groups a central secretariat based at Harwell (UK) has provided guidance, established and administered databases of contacts and produced a series of national reports.

This paper describes the achievements of the Activity and discusses work proposed for the future.     

Fluorine analysis of nuclear waste glasses

A method for analyzing the fluorine content of glass using a microwave oven to digest the glass is presented. Analysis time and secondary waste generation are reduced using this method, without sacrificing accuracy.     

Anaerobic digestion of alkaline black liquor using an up-flow anaerobic sludge blanket reactor

The anaerobic digestion of alkaline black liquor from a cereal straw pulping mill was studied in batch (serum bottles) and continuous systems (up-flow anaerobic sludge blanket reactor—UASB). The batch digestion studies confirmed that lignin and related compounds (LRC) in the alkaline black liquor were the main inhibitory substances and could not be decomposed by anaerobic bacteria. At organic loading rates of 5–10 kg COD m^?3 day^?1, the UASB reactor achieved 50–60% COD removal efficiencies. Gas production was 2–3 dm³ per dm³ of alkaline black liquor. Two different sludge types were examined in the reactor: granular and cluster-like sludges. Sludge in a cluster, which involved many small granules and flocs, tended to form larger aggregates and possessed good settling ability.     

Mechanisms of Nausea and Vomiting: Current Knowledge and Recent Advances in Intracellular Emetic Signaling Systems

Nausea and vomiting are common gastrointestinal complaints that can be triggered by diverse emetic stimuli through central and/or peripheral nervous systems. Both nausea and vomiting are considered as defense mechanisms when threatening toxins/drugs/bacteria/viruses/fungi enter the body either via the enteral (e.g., the gastrointestinal tract) or parenteral routes, including the blood, skin, and respiratory systems. While vomiting is the act of forceful removal of gastrointestinal contents, nausea is believed to be a subjective sensation that is more difficult to study in nonhuman species. In this review, the authors discuss the anatomical structures, neurotransmitters/mediators, and corresponding receptors, as well as intracellular emetic signaling pathways involved in the processes of nausea and vomiting in diverse animal models as well as humans. While blockade of emetic receptors in the prevention of vomiting is fairly well understood, the potential of new classes of antiemetics altering postreceptor signal transduction mechanisms is currently evolving, which is also reviewed. Finally, future directions within the field will be discussed in terms of important questions that remain to be resolved and advances in technology that may help provide potential answers.     

氟硅酸钾滴定法测定粗制氟化钠中二氧化硅

采用硝酸-氢氟酸混合酸为消解溶剂,通过微波消解技术对粗制氟化钠进行快速消解,并用氟硅酸钾滴定法测定其二氧化硅含量。选择饱和氯化钾溶液替代固体氯化钾作为沉淀剂,考察了消解酸体系、饱和氯化钾溶液用量、沉淀温度、沉淀放置时间、共存元素干扰及指示剂选择等条件对测定结果的影响并进行优化。确定了最优测试条件：以8 mL硝酸+2 mL氢氟酸为消解溶剂,以8 mL饱和氯化钾溶液为沉淀剂,控制沉淀温度为20~25 ℃、沉淀放置时间为15 min,选择50 g/L氯化钾-50%乙醇溶液洗涤沉淀,采用溴麝香草酚蓝-酚红指示剂。该方法应用于回收粗制氟化钠中二氧化硅含量的测定可大幅度缩短分解试样的时间,有效降低检测成本,回收率为99.15%~100.63%,相对标准偏差（RSD,n=8）小于1%,与传统高温碱熔法测定结果相符,方法的准确度和精密度较好。     

伊利石在铝酸钠溶液中的反应脱硅过程研究

为了更清楚地了解伊利石在拜耳法溶出过程中的反应行为，本文对伊利石在合成铝酸钠溶液中的溶出动力学进行了研究，测得其活化能为114，73kJ/mol。并研究了溶液苛性碱浓度对伊利石的反应速率的影响；添加石灰可以有效的增加伊利石的反应率，提高脱硅效率。为拜耳法生产氧化铝的脱硅过程及防止结疤提供理论依据。     

城市污水处理厂污泥中温两相厌氧消化的研究

采用中温两相厌氧消化处理西安市污水处理厂污泥,结果表明,污泥可在较短的停留时间(296 h,产酸相30 h,产甲烷相266 h),较高的有机负荷(约2.65 kg VS/m3.d)下稳定运行,系统VS去除率38.87%,pH≈7.5,产气速率6.33 L/L.d,单位VS产气率3.00 L/g。与单相厌氧消化处理结果对比,两相厌氧消化系统的停留时间可减少一半,而污泥有机负荷提高2倍,且有机物的去除率大,处理效果好,稳定性高,抗冲击负荷能力强,产气性良好。     

微波消解法测定化学需氧量

探讨利用微波消解法代替回流加热，缩短了测定时间，并与标准法进行准确度比较。     

Coupling System for Food Wastes Anaerobic Digestion and Polyhydroxyalkanoates Production with Ralstonia eutropha

A new technology was developed to couple the anaerobic digestion of food wastes with production of polyhydroxyalkanoates (PHAs). Acetic, propionic, butyric and lactic acids were produced during food wastes anaerobic digestion and their concentrations reached 5.5, 1.8, 27.4 and 32.7 g/L, respectively under appropriate digestion conditions. The fermentative acids were transferred through a dialysis membrane to an air-lift reactor for PHA synthesis by Ralstonia eutropha. Dry cell concentration and PHA content reached 22.7 g/L and 72.6%, respectively. The obtained PHA was a copolymer of b-hydroxybutyrate (HB) and b-hydroxyvalerate (HV) with 2.8% (mole ratio) of HV units in polymer.     

水中重金属连续消解装置及性能研究

本研究设计了一种用于水体中重金属测定的连续消解装置,该消解装置可据水质特点调节消解温度、压力和流速。实际水样加标经消解后分析,8种金属离子(Cd、Pb、Cr、Cu、Zn、As、Fe和Mn)的平均回收率在93.1%~99.4%之间,RSD为3.3%~8.7%;通过对自来水、地下水、地表水和污水分别进行连续消解、微波消解和石墨消解,连续消解后溶液中8种金属元素浓度测定结果与微波消解和石墨消解无显著差异,且平行样相对误差不大于5%,表明本连续消解具有较高的准确度和精密度,适用于不同水体的消解分析要求。该连续消解装置可自由设定消解参数,实现自动化运行,通过与各类重金属在线监测仪器接口连接,有望实现监测过程中水样的自动化消解。