利用城市垃圾焚烧飞灰制备微晶玻璃的研究

利用上海御桥垃圾焚烧厂的焚烧飞灰为主要原料,通过添加SiO2、Al2O3、NaOH组分在实验室研制成功了以硅灰石(wollastonite)为主晶相的微晶玻璃.该体系微晶玻璃制备的最佳工艺条件为:熔融温度1500℃、熔融时间1 h,核化温度为920℃,核化时间1.5 h,晶化温度为1150～1180℃,晶化时间为2 h.研究结果表明,硅灰石为主晶相的微晶玻璃对Pb、Cr和Cd重金属具有很强的稳定束缚能力.     

垃圾焚烧发电厂周边土壤多溴联苯醚污染特征及来源解析

为了分析市政垃圾焚烧发电厂PBDEs(polybrominated diphenyl ethers,多溴联苯醚)排放对周边环境的影响,于2012年8—9月,在哈尔滨2座市政垃圾焚烧发电厂周边共采集20个表层(0~10 cm)土壤样品,分析土壤中PBDEs的污染特征及其来源. 结果表明:垃圾焚烧发电厂周边土壤中w(∑₁₂PBDEs)(12种PBDEs的质量分数之和)为5.32~169 ng/g(以干质量计,下同),平均值为62.9 ng/g;PBDEs的主要组分为BDE-209,w(BDE-209)为5.18~169 ng/g,占w(∑₁₂PBDEs)的95%以上;w(∑₁₂PBDEs)显著高于2006年哈尔滨市区污染土壤值,二者相差1~2个数量级. 由于垃圾处理年限和处理量差异较大,垃圾焚烧发电厂A周边土壤中w(PBDEs)显著高于垃圾焚烧发电厂B. 与国内其他用地类型污染土壤相比,垃圾焚烧发电厂周边土壤中PBDEs处于中度污染水平. 主成分分析结果显示,PBDEs主要来源于商用十溴联苯醚及其降解物和商用五溴联苯醚.      

城市生活垃圾堆肥厂臭气的产生及防控技术进展

阐述了城市生活垃圾堆肥厂臭气的产生、成分及其危害,认为垃圾堆肥厂臭气成分概括来讲主要分为硫化物、胺类、挥发性脂肪酸、酮类以及醛类,但详细、完整的臭气成分还有待于今后进一步研究。对于臭气的防止及其控制技术,进行了总结。堆肥臭气主要防止措施包括在堆肥结构、通气方式、外加改良物质等方面进行的优化与控制。着重介绍了四种生物除臭法,即生物过滤法、生物洗涤法、生物滴滤法和曝气式生物除臭法的各自特点和技术进展。最后认为由于垃圾堆肥恶臭成分的多样性,单一的处理方法往往效果有限,两种或两种以上的方法联用具有较好的发展前景。     

我国填埋渗滤液产量影响因素分析及估算方法构建

在综述已有研究结果的基础上,构建了适合我国国情的渗滤液产量估算方法,根据来源将渗滤液概化为降水和垃圾自产水2部分.采用HELP模型获得31个典型城市气候特征下的渗出系数取值;按照产生原理,垃圾自产水分为压缩产水和降解产水,分别建立估算公式并给出田间持水率和组分降解率的取值建议.应用此方法,估算了10个城市的填埋渗滤液产生量.发现在填埋40a内,垃圾自产水占渗滤液总量的52%~82%,说明垃圾自产水的贡献不可忽视.我国不同地区的降水渗出系数和生活垃圾性质差异,使得填埋渗滤液产量具有显著的地域差异性,在选择渗滤液处理方式时应因地制宜.     

城市生活垃圾资源化途径之一--垃圾焚烧发电

文章通过垃圾焚烧发电工程实例,介绍了垃圾焚烧发电的原理、特点以及较好的经济效益、环境效益和社会效益,阐述了垃圾焚烧发电是符合循环经济模式,对当前解决垃圾处理问题的必要性.     

Estimating source strengths of HCl and SO2 emissions in the flue gas from waste incineration

HCl and SO_2 emission is one of the major concerns related to municipal solid waste incinerator(MSWI). In this study, a material flow analysis model was developed to estimate the HCl and SO_2 concentrations in the MSWI flue gases(FGs), and their concentrations in the full-scale MSWI were monitored. The calculated concentrations of HCl and SO_2 in the FG were 770–1300 mg/Nm~3 and 150–640 mg/Nm~3, respectively, in close agreement with the monitored values. More than 99% of Cl and 92% of S from the FG were captured into solid residues by the air pollution control(APC) systems. Moreover, since only 48.4%–67.5% of Cl and 21.3%–53.4% of S were transferred to the FG from the municipal solid waste(MSW), it was more reliable to estimate the source strengths and release amounts of HCl and SO_2 in the FG based on the amounts of Cl and S in the APC residues(AR) and exhaust gas rather than in the MSW. This simple method is easily applicable and the estimated results could provide scientific basis for the appropriate design and operation of the APC systems as well as corrosion control of heat recovery systems.     

Seasonal variation of municipal solid waste generation and composition in four East European cities

The quality of recyclable and residual municipal solid waste (MSW) is, among other factors, strongly influenced by the seasonal variation in MSW composition. However, a relatively marginal amount of published data on seasonal MSW composition especially in East European countries do not provide sufficient information on this phenomenon. This study provides results from municipal waste composition research campaigns conducted during the period of 2009–2011 in four cities of Eastern European countries (Lithuania, Russia, Ukraine and Georgia). The median monthly MSW generation values ranged from 18.70 in Kutaisi (Georgia) to 38.31 kg capita⁻¹ month⁻¹ in Kaunas (Lithuania). The quantitative estimation of seasonal variation was performed by fitting the collected data to time series forecasting models, such as non-parametric seasonal exponential smoothing, Winters additive, and Winters multiplicative methods.     

Techno-economic analysis and environmental impact assessment of energy recovery from Municipal Solid Waste (MSW) in Brazil

Due to the lack of appropriate policies in the last decades, 60% of Brazilian cities still dump their waste in non-regulated landfills (the remaining ones dump their trash in regulated landfills), which represent a serious environmental and social problem. The key objective of this study is to compare, from a techno-economic and environmental point of view, different alternatives to the energy recovery from the Municipal Solid Waste (MSW) generated in Brazilian cities. The environmental analysis was carried out using current data collected in Betim, a 450,000 inhabitants city that currently produces 200 tonnes of MSW/day. Four scenarios were designed, whose environmental behaviour were studied applying the Life Cycle Assessment (LCA) methodology, in accordance with the ISO 14040 and ISO 14044 standards. The results show the landfill systems as the worst waste management option and that a significant environmental savings is achieved when a wasted energy recovery is done. The best option, which presented the best performance based on considered indicators, is the direct combustion of waste as fuel for electricity generation. The study also includes a techno-economical evaluation of the options, using a developed computer simulation tool. The economic indicators of an MSW energy recovery project were calculated. The selected methodology allows to calculate the energy content of the MSW and the CH₄ generated by the landfill, the costs and incomes associated with the energy recovery, the sales of electricity and carbon credits from the Clean Development Mechanism (CDM). The studies were based on urban centres of 100,000, 500,000 and 1,000,000 inhabitants, using the MSW characteristics of the metropolitan region of Belo Horizonte. Two alternatives to recovering waste energy were analyzed: a landfill that used landfill biogas to generate electricity through generator modules and a Waste-to-Energy (WtE) facility also with electricity generation. The results show that power generation projects using landfill biogas in Brazil strongly depend on the existence of a market for emissions reduction credits. The WtE plant projects, due to its high installation, Operation and Maintenance (O&M) costs, are highly dependent on MSW treatment fees. And they still rely on an increase of three times the city taxes to become attractive.