微波消解-原子吸收光谱法间接测定垃圾中的硫含量

建立了用微波消解技术处理样品,原子吸收光谱法间接测定城市生活垃圾中硫含量的分析方法。优化了微波消解及原子吸收仪器的最佳操作条件。方法可用于城市生活垃圾中硫的测定,相对标准偏差小于2.5%,回收率为95.3%～101.7%。     

垃圾要正确分类

对于大多数市民不了解垃圾如何进行分类，有关环保专家建议，培养市民环保意识，从正确分类垃圾做起。环保专家对城市生活垃圾按源头分类方法归类如下：     

废弃纸尿裤的处理和回收利用研究进展

随着生活水平提高和老龄化的加剧,一次性纸尿裤使用量大幅上升,目前已成为继厨房垃圾和塑料之外的第三大生活固体垃圾,因此,废弃纸尿裤的处理和回收是一个重要课题.虽然国外已有一些关于废弃纸尿裤的回收处理案例,但我国在废弃纸尿裤回收处理方面的研究报道不多.因此,本文在介绍了废弃纸尿裤处理的现状、纸尿裤的结构组成的基础上,综述了...     

城市生活垃圾典型有机组分混合热解特性的研究

利用自行设计的较大物量(约10 g)的热重分析装置对城市生活垃圾典型有机组分（纸屑、木屑、织物、塑料、橡胶、厨余）的混合热解特性进行了实验研究，并用最小二乘法计算得到由若干平行反应组成的热解反应动力学模型，实验结果与模型计算结果吻合较好。在此基础上对城市生活垃圾典型有机组分混合热解中的交互影响和非线性规律进行了分析。结果表明，城市生活垃圾典型有机组分混合热解动力学模型由2个～4个平行反应组成；混合热解中有反应发生合并的现象；热效应和组分比例对混合物综合热解特性有显著影响。     

TGA技术研究城市生活垃圾燃烧特性

采用TGA（热解重量分析法）技术,考察了山西省晋城市区生活垃圾不同组分的着火及燃烧特性,实验室出了原生垃圾中不同组分（包括废塑料类,废纸类,废弃织物类,植物类,厨余类和细粒类）垃圾的TG／DTG曲线,着火温度及其它燃烧特征参数,通过对TG／DTG曲线,着火温度及燃烧特征参数的分析,首次提出了一种在TGA技术中确定着火温度的新方法,给出上述不同垃圾组分的开始热分解温度,着火温度,燃尽温度以及平均燃烧速率等重要参数,并对各种垃圾的着火及燃烧特性进行了对比研究,为垃圾焚烧工业化应用提供了基础数据。     

美国约翰霍普金斯大学化学系教学实验室访学见闻

介绍了对美国约翰霍普金斯大学化学系教学实验室访问学习见闻。通过访问学习,发现其系统全面的实验室安全教育方式、行之有效的实验室安全管理措施、实验室垃圾与生活垃圾的分类处理办法及网络辅助实验教学模式、注重学生课堂实验笔记的实验课成绩评定方式等方面,都值得我们学习和借鉴。     

《恶臭的评价与分析》

该书全面地介绍了恶臭评价理论、暴露评价的数学模式及此模式在城市垃圾和污水风险管理中的应用，讨论了恶臭治理原理．并详细论述了畜牧业恶臭物质的资源化问题。书中比较完整地描述了恶臭的嗅觉测定、仪器分析方法及恶臭污染源调查的采样布点技术，以及恶臭的风险管理和污染控制。     

城市生活垃圾焚烧体系化学热力学平衡分析

采用化学热力学平衡分析方法，分析城市生活垃圾焚烧体系污染物的排放特性。主要计算了聚氯乙烯（PVC）及典型城市垃圾焚烧过程氯元素的化学平衡组成及其浓度，同时研究了脱氯剂对PVC及垃圾中氯转化的影响。计算结果表明，PVC热态反应的主要产物是HCl气体，在加入脱氯剂后温度低于600℃时，脱氯剂对HCl的脱除作用很明显；城市生活垃圾热解和燃烧过程中在温度超过600 ℃，垃圾中的有机氯和无机氯都将转化为HCl气体，而此时脱氯剂失去效果。由计算结果得到控制HCl生成，消除二口恶英污染物的生成反应工艺条件。     

PVC塑料流化床气化试验研究

为开发城市生活垃圾低污染流化床气化与旋风燃烧熔融技术,研究了垃圾中广泛存在的PVC塑料在流化床内的气化特性与污染物生成机理。不同温度和过量空气系数下进行了流化床PVC气化试验,分析了不同工况对PVC中Cl转化为HCl的影响。实验结果表明,反应高于600 ℃、过量空气系数大约0.4时,Cl转化为HCl的选择性达到95％以上;气化效率达到22％～25％,气化气热值达到2 000 kJ/m3～2 300 kJ/m3。反应高于700 ℃,PVC流化床气化生烟量明显减少,过量空气系数0.6时,生烟量减少到PVC质量的10％左右。提出的HCl析出与生烟机理较好地解释了试验结果,为城市生活垃圾气化熔融技术提供了相关基础数据与污染物生成及控制方法。     

城市生活垃圾灰渣的熔融和黏温特性研究

城市生活垃圾灰渣的熔融及黏温特性对其固定床熔渣气化炉的优化设计和操作具有重要指导意义。本文分析了上海老港垃圾(LG)和扬州成型垃圾(YZ)的灰成分特征,利用高温热台显微镜、X射线衍射仪(XRD)及FactSage模拟探究了垃圾灰的熔融机制,同时结合高温黏度计、扫描电镜-能谱分析仪(SEM-EDS)和XRD分析晶体矿物质生成对灰渣黏度变化的影响。结果表明,两种生活垃圾灰的硅铝比均较高,但铝钙含量差异较大。YZ灰流动温度比LG灰约高150℃,与LG灰中形成易低温共熔的硅灰石,而YZ灰在高温下仍存在石英及尖晶石有关。两种灰渣的熔融均符合“熔融-溶解”机制,且随温度升高均经历收缩、熔融和扩散过程。两条黏温曲线均呈现玻璃渣的特征,但YZ灰的黏度增长较快,与其降温过程产生长条状钙长石晶体有关。以YZ为气化原料需较高的排渣温度,而LG灰的熔融特性和黏温特性均较好,应用此原料气化炉可操作温度范围大。     

Characteristics of gaseous product from municipal solid waste gasification with hot blast furnace slag

Possibility of combustible gas production from municipal solid waste (MSW) using hot blast furnace (BF) slag has been studied. The objective of this work is to generate combustible gas from MSW using heated BF slag. In this experiment, the thermal stability of the MSW was analyzed by thermogravimetric analysis, and effects of temperature, gasifying agent (air, N2, steam) and BF slag on the gas products were investigated at 600-900 ℃. The thermogravimetric analysis indicates that the weight loss of MSW includes four stages: evaporation of the moisture, combustion of volatile materials, burning of carbon residue and burnout of ash. The contents of the combustible gas increase with increasing temperature, and the lower calorific value (LCV) increases rapidly at 600-900 ℃. It is found that volume fraction of CO, H2 and CH4 at different atmospheres increases in the order N2相似文献   

垃圾催化燃烧的热重分析研究

采用热重分析,结合机理分析的方法,探讨了不同催化剂对垃圾焚烧过程中着火性能和燃尽性能的影响。结果表明,催化剂对垃圾着火性能的提高主要是催化剂促进了垃圾中挥发性有机物的释放,使着火点提前;催化剂对垃圾燃尽性能的提高,主要作用机理是催化剂充当氧的载体,促进氧转移。提出了表征着火性能和燃尽性能的两个物理参数,并根据两个参数对催化剂进行排序和比较。催化剂影响着火性能大小进行排序：K2CO3> MnO2 > Na2CO3> CuO > MgO > TiO2 > Al2O3 > Fe2O3 > BaCO3> CaO;催化剂影响垃圾燃尽性能大小排序：Na2CO3>MgO> MnO2> K2CO3> BaCO3> CaO> Al2O3> CuO> Fe2O3> TiO2。     

城市生活垃圾的燃烧特性

选取城市生活垃圾中的九种典型级分进行热重特性试验，根据热失重曲线得出反应动力力学参数及反应速率控制方程，提出燃烧指数表征垃圾的燃烧特性。研究结果表明，垃圾中不同的组分的燃烧特性判别很大，不同的垃圾控制燃烧反应的过程是不同的，废塑料，废纸和废棉布类符合两段燃烧模型，且低温段的动力学参数Ｅ和Ａ远大于高温段，其余六处组分可用一段模型来描述，计算得出的失重关系式能较好地反映垃圾燃烧的失重过程，挥 分高的垃     

Thermostability of Selected Enzymes in Organic Wastes and in their Humic Extract

The objective of this study was to evaluate the thermostability up to 70 degrees C for 1 h of selected enzymes present in fresh and composted sewage sludge (SS and SSC) or municipal solid wastes (MSW and MSWC) and their humic extract. After a thermal treatment at 70 degrees C, no beta-glucosidase activity in any humic extract was detected, whereas in SS, SSC, MSW, and MSWC, it was respectively, 35%, 68%, 17%, and 12% compared to thermally untreated samples. By contrast, o-diphenol oxidase activity was even stimulated by thermal treatment in SS samples, but in the humic extracts, this activity decreased by 75-81%. Urease activity in all humic extracts decreased by 70% or more just at 40 degrees C, whereas for organic wastes, this decrease was observed after treatment at 70 degrees C. Alkaline phosphatase (AP) activity was affected by thermal treatment only in MSW and MSWC. In humic extracts, AP activity decreased gradually to zero except for the MSW extract, where 45% activity was retained after treatment at 70 degrees C. In general, thermostability of enzymes in humic extracts was lower than the materials they were extracted from.     

Conversion of municipal solid waste into carboxylic acids by anaerobic countercurrent fermentation: effect of using intermediate lime treatment

Municipal solid waste (MSW) and sewage sludge (SS) were combined and anaerobically converted into carboxylate salts by using a mixed culture of acid-forming microorganisms. MSW is an energy source and SS is a source of nutrients. In this study, MSW and SS were combined, so they complemented each other. Four fermentors were arranged in series for a countercurrent fermentation process. In this process, the solids and liquid were transferred in opposite directions, with the addition of fresh biomass to fermentor 1 and fresh liquid media to fermentor 4. An intermediate lime treatment of solids exiting fermentor 3 before entering fermentor 4 was applied to improve the product acid concentration from the untreated MSW/SS fermentations. All fermentations were performed under anaerobic conditions at 40 degrees C. Calcium carbonate was added to neutralize the carboxylic acids and to control the pH. Iodoform was used as a methanogen inhibitor. Carboxylic acid concentration and gas composition were determined by gas chromatography. Substrate conversion was measured by volatile solids loss, and carboxylic acid productivity was calculated as the function of the total carboxylic acids produced, the amount of liquid in all fermentors, and time. The addition of intermediate lime treatment increased product concentration and conversion by approx 30 and 15%, respectively. The highest carboxylic acid concentrations for untreated MSW/SS fermentations with and without intermediate lime treatment were 22.2 and 17.7 g of carboxylic acid/L of liquid, respectively. These results confirm that adding a treatment step between fermentor 3 and fermentor 4 will increase the digestibility and acid productivity of the fermentation.     

Conversion of municipal solid waste into carboxylic acids by anaerobic countercurrent fermentation

Municipal solid waste (MSW) and sewage sludge (SS) were combined and anaerobically converted into carboxylate salts by using a mixed culture of acid-forming microorganisms. MSW is an energy source and SS is a source of nutrients. In this study, MSW and SS were combined, so they complemented each other. Four fermentors were arranged in series for a countercurrent fermentation process. In this process, the solids and liquid were transferred in opposite directions, with the addition of fresh biomass to fermentor 1 and fresh liquid media to fermentor 4. An intermediate lime treatment of solids exiting fermentor 3 before entering fermentor 4 was applied to improve the product acid concentration from the untreated MSW/SS fermentations. All fermentations were performed under anaerobic conditions at 40°C. Calcium carbonate was added to neutralize the carboxylic acids and to control the pH. Iodoform was used as a methanogen inhibitor. Carboxylic acid concentration and gas composition were determined by gas chromatography. Substrate conversion was measured by volatile solids loss, and carboxylic acid productivity was calculated as the function of the total carboxylic acids produced, the amount of liquid in all fermentors, and time. The addition of intermediate lime treatment increased product concentration and conversion by approx 30 and 15%, respectively. The highest carboxylic acid concentrations for untreated MSW/SS fermentations with and without intermediate lime treatment were 22.2 and 17.7 g of carboxylic acid/L of liquid, respectively. These results confirm that adding a treatment step between fermentor 3 and fermentor 4 will increase the digestibility and acid productivity of the fermentation.     

An evaluation of the modified BCR sequential extraction procedure to assess the potential mobility of copper and zinc in MSW

Copper and zinc were determined in municipal solid waste (MSW) samples with different deposit ages from Tianziling landfill site. The pseudototal metal contents of the MSW samples were determined following an aqua regia digestion. Operational speciation was performed using the modified BCR sequential extraction procedure. Analyses were carried out by AAS. Agreement between most of triplicate samples was acceptable. The amount of copper and zinc extracted in the sequential procedure (i.e. Step 1, Step 2, Step 3, residual) did not generally agree well with pseudototal digestion. Various MSW samples contained significant different levels of copper and zinc, but these were with different potential migrations. For example, 49.88%-76.34% of copper existed in five MSW samples was present as oxidable fraction while ~ 40% of zinc was present as acid soluble fraction. The study illustrates the feasibility and importance of modified BCR sequential extraction procedure used as evaluation method when assessing the potential mobility of heavy metal in MSW landfill.     

Cellulase Hydrolysis of Unsorted MSW

A recent development in waste management and engineering has shown that the cellulase can be used for the liquefaction of organic fractions in household waste. The focus of this study was to optimize the enzyme hydrolysis of thermally treated municipal solid waste (MSW) by the addition of surfactant. Concurrently, the enzyme performance was analysed on pure cellulose in a solution of MSW wastewater. Results showed no effect of surfactant addition to the hydrolysis media as measured by viscosity and particle size distribution. MSW treatment wastewater was found to contain a high amount of calcium, potassium, sodium, chloride and others that may affect cellulolytic enzymes. Cellulase performance showed no effect of adding the metal ion-chelating agent EDTA to the solution. The cellulases were stable, tolerated and functioned in the presence of several contaminants.     

城市生活垃圾与煤矸石混烧特性及其HCl排放特性研究

利用热重分析仪对城市生活垃圾与煤矸石单独及混合燃烧特性进行了研究,并采用高温管式炉燃烧装置考察了PVC、NaCl及MSW与煤矸石混烧过程中HCl的排放规律。结果表明,在煤矸石中掺烧部分MSW可有效改善煤矸石的燃烧特性,尤其是脱挥发分和着火特性。综合考虑燃烧特性变化,建议MSW掺混比例为20%。PVC与NaCl掺混比较低时,煤矸石可抑制PVC燃烧过程中HCl的析出,会显著促进NaCl中HCl的析出;当掺混比增大时,上述作用逐渐减弱。MSW与煤矸石混烧时,会促进HCl的析出,增大烟气中HCl的浓度。当掺混比为10%时,HCl排放浓度达到56.22 mg/m~3,已超过中国国家标准,必须采取相应脱氯措施。     

Analytical pyrolysis of re-circulated leachates: Towards an improved municipal waste treatment

The harmless removal of municipal solid waste (MSW) requires the biodegradation of organic matter to decrease the risk of gaseous emissions and leaching of contaminants. We studied the re-circulation of leachates from an aerobic treated MSW in a lysimeter and compared these results with a similar laboratory study using small-scale reactors. The reduction of total organic C and biological and chemical oxygen demands provided clear evidence for the biodegradation of organic matter in MSW after 12 months of leachate re-circulation. Curie-point pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and pyrolysis-field ionization mass spectrometry (Py-FIMS) revealed that the biodegradation was more efficient in the large-scale lysimeter than in the laboratory reactors. Different from the laboratory experiments, carbohydrates and N-containing compounds were decomposed almost completely after 2 months. Furthermore, temperature-resolved Py-FIMS showed that leachate re-circulation led to a higher thermal stability of the residual, non-decomposed organic matter. In summary, the two analytical pyrolysis methods proved that the re-circulation of leachates through MSW promoted organic matter biodegradation and offers an improved aerobic waste treatment technology.