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.     

厌氧胶快速渗补技术在汽车发动机上的应用

将金属铜易与过氧化物发生氧化还原反应生成游离基的原理应用于厌氧胶，开发了针时金属零件表面微孔进行局部渗补的实用技术。在相关技术可靠性和工艺可行性得以论证的前提下。将局部渗补技术成功地应用于渗补发动机泄漏缸盖，减少了废品损失，取得了良好的经济效益。     

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.     

五氯酚在厌氧生物体系中的降解及反馈作用

为探讨厌氧系统降解五氯酚(PCP)能力及PCP对厌氧系统的毒性影响,采用UASB反应器进行了PCP模拟污水连续流试验,考察了不同PCP浓度及负荷条件下系统对PCP和COD的降解去除规律,揭示了PCP对系统产酸相和产甲烷相影响状况.结果表明,在进水PCP含量从无到开始加入、PCP浓度提高以及PCP负荷提高3个冲击变化阶段,厌氧系统对PCP和COD的去除率均表现出先迅速降低后缓慢升高的变化趋势,运行稳定后PCP和COD的去除率分别达91.2%和83.5%以上.PCP对厌氧系统中微生物种群产生影响,使系统产酸菌由丁酸型菌群为主逐渐演替为丙酸型菌群为主,PCP对系统产甲烷菌活性产生明显抑制,甲烷产量由PCP加入前的12.1L/d降低至加入后的2.5L/d.     

污水处理厂污泥厌氧消化优化设计与运行探讨

对国内典型的污水处理厂污泥厌氧消化系统进行调研发现,厌氧消化系统的运行管理尚存在诸多问题。在总结白龙港污水处理厂污泥厌氧消化调试与运行管理经验的基础上,针对厌氧消化工艺存在的普遍性问题,提出了厌氧消化系统设计和运行管理方面的建议,以促进工艺设计优化,提高运行管理水平。     

快速测定化学需氧量的方法

利用分光光度法、微波密封消解法测定水样中的化学需氧量，并把测定的精密度、准确度与国标回流法相比较，结果证明：分光光度法、微波消解法是测定化学需氧量的快捷方法，具有省时、省试剂、工作效率高的特点。     

土壤样品的微波消解及其痕量铀的分析

对3个土壤样和2个放射性河床沉积物的国家标准物质进行了微波消解，又采用TOPO萃取和液体荧光法分析了样品中的铀含量，并将分析结果与国家标准方法GB11220．2-89的分析结果进行了比较。结果表明，微波消解法与国家标准方法一样，均不能实现土壤的全部消解，但与国家标准方法相比较，微波消解速度快，所需试剂量少，且易于实现定量控制，铀回收率高，分析精度高。对不溶物进行X射线能谱分析发现，其主要组成为铝、钛及过渡金属的氟化物或氧化物。同位素质谱分析表明，国家标准物质GBW08304中的^234U，^235U均比天然丰度低，另一个国家标准物质GBW08304a中铀的同位素分布与天然组成基本一致。     

低温拜耳法赤泥高温溶出行为

赤泥是氧化铝生产过程中排放的强碱性固体废物,尤其对于三水铝石矿低温拜耳法产生的赤泥,其中含有大量的Al₂O₃未被溶出,造成资源的极大浪费。以低温拜耳法赤泥为原料,通过高温溶出回收其中的Al₂O₃,系统研究了石灰添加量、循环母液苛碱浓度、溶出温度、固含、溶出时间对Al₂O₃溶出性能的影响规律,获得了溶出过程中物相转变机理和溶出动力学。结果表明：低温拜耳法赤泥高温溶出过程中,Al₂O₃溶出率随苛碱浓度、溶出温度、时间的增加而增加,随着石灰添加量和固含的增加而降低。推荐Al₂O₃的溶出条件为：固含500 g/L、苛碱浓度210 g/L、溶出温度270℃、溶出时间60 min、溶出过程不添加石灰,在此条件下Al₂O₃溶出率为50.36%,溶出液硅量指数为260。Al₂O₃溶出过程受内扩散控制...     

Having a Same Type IIS Enzyme’s Restriction Site on Guide RNA Sequence Does Not Affect Golden Gate (GG) Cloning and Subsequent CRISPR/Cas Mutagenesis

Golden gate/modular cloning facilitates faster and more efficient cloning by utilizing the unique features of the type IIS restriction enzymes. However, it is known that targeted insertion of DNA fragment(s) must not include internal type IIS restriction recognition sites. In the case of cloning CRISPR constructs by using golden gate (GG) cloning, this narrows down the scope of guide RNA (gRNA) picks because the selection of a good gRNA for successful genome editing requires some obligation of fulfillment, and it is unwanted if a good gRNA candidate cannot be picked only because it has an internal type IIS restriction recognition site. In this article, we have shown that the presence of a type IIS restriction recognition site in a gRNA does not affect cloning and subsequent genome editing. After each step of GG reactions, correct insertions of gRNAs were verified by colony color and restriction digestion and were further confirmed by sequencing. Finally, the final vector containing a Cas12a nuclease and four gRNAs was used for Agrobacterium-mediated citrus cell transformation. Sequencing of PCR amplicons flanking gRNA-2 showed a substitution (C to T) mutation in transgenic plants. The knowledge derived from this study could widen the scope of GG cloning, particularly of gRNAs selection for GG-mediated cloning into CRISPR vectors.