城市生活垃圾和污水处理厂剩余污泥混合发酵的原料配比优化研究

以城市生活垃圾和污水处理厂的剩余污泥为混合原料,研究了混合原料的不同配比对厌氧发酵过程及产气的影响。结果表明:城市生活垃圾与剩余污泥以挥发性固体(VS)质量比为2∶1混合后,厌氧发酵效果最好,累计产气量最高,达到8 721mL,发酵后的总固体(TS)、VS、COD去除率分别达43.65%、35.98%、47.88%;各实验组在发酵过程中的pH、氨氮浓度和碱度均在合理范围内,未对厌氧发酵反应造成影响;以适当配比的城市生活垃圾和剩余污泥为混合原料,进行中温联合厌氧发酵是可行的,联合厌氧发酵可以弥补单一原料的缺陷,在一定程度上改善厌氧发酵效果。     

水泥窑处置生活垃圾过程中的TOC排放

随着水泥窑协同处置生活垃圾、污泥和危废等技术的推广应用,相关环保控制要求也不断提高,处置过程烟道气中总有机碳(total organic carbon,TOC)含量高低,也逐渐成为人们关注和控制的目标。为了消除人们的疑虑,将未经发酵的筛下(厨余)物直接加入低温烘干粉磨的水泥生料磨系统中,经实验检测分析和工程现场测试实践证明,在控制一定添加量的情况下,该过程中各环节TOC含量非但不会增加,反而有所降低,其降幅高达40%。     

城市生活垃圾中纤维素含量测定方法优化

对传统硫酸法进行改进,建立适用于城市生活垃圾纤维素含量的测定方法。以脂肪抽提时间、硫酸浓度、水解反应温度、水解反应时间、稀释硫酸浓度、回流时间为考察因素进行6因素5水平正交实验。结果表明,测定纤维素含量的最佳条件为：脂肪抽提时间4h、硫酸浓度70％、水解反应温度30℃、水解反应时间5h、稀释硫酸浓度5％、回流时间3h。优化后纤维素测定条件RSD均小于1．69％,平均回收率98．76％,表明该方法的精度高,可靠行强。     

3AMBR工艺处理城市污水节能降耗的中试实验

为探索 MBR 污水厂切实可行的节能途径,构建了处理规模为1 m3·h-1的3AMBR（anoxic-anaerobic-anoxic membrane bio-reactor）工艺中试实验系统,以曝气量、回流比及进水方式等参数为研究对象,优选了4套方案,进行了超过200 d的现场实验。实验期间,各方案出水水质良好,优化方案的脱氮效率提高明显。当减少曝气,使好氧池在低溶氧（DO-1）状态下运行,仍可保证系统出水的稳定达标排放;提高膜池液向好氧池的回流,使膜池的富余溶解氧得到了利用,达到了部分或完全替代曝气的效果,且获得了更好的脱氮能力;多点进水（比例为2∶2∶1）降低了系统前端的污染负荷,合理分配了碳源,使系统对含氮污染物等的去除能力提高,虽然总体能耗无显著变化,但处理能力的增强明显提升了能效。     

生活垃圾处理的低碳化研究进展

在“碳中和”背景下,对国内外生活垃圾处理低碳化发展的现状及研究进展进行了回顾与研究。分析了生活垃圾填埋、焚烧、堆肥处理等过程中的温室气体排放问题,并对碳排放的主要核算方法及工具进行了综述。结合“无废城市”、循环经济等先进理念,对我国生活垃圾低碳化治理的政策法规和技术路径进行了梳理。为准确核证垃圾处理过程的碳排量,应建立符合我国实际的碳排放监测、报告、核查标准体系。宜采取减量化、资源化和系统化的管理策略与技术手段,提高资源、能源的回收利用率,以促进减污降碳协同增效。各地应充分考虑其经济发展水平、垃圾产量组分和处理利用能力等,通过全生命周期的经济、社会与生态环境等多目标综合分析,采取优化组合的分类处理技术路线。     

Classification and comparison of municipal solid waste based on thermochemical characteristics

Municipal solid waste (MSW) has been normally sorted into six categories, namely, food residue, wood waste, paper, textiles, plastics, and rubber. In each category, materials could be classified further into subgroups. Based on proximate and ultimate analysis and heating value, statistical methods such as analysis of variance (ANOVA) and cluster analysis were applied to analyze the characteristics of MSW in every subgroup and to try to distinguish their relative properties. The chemical characteristics analysis of MSW showed that polyethylene (PE), polypropylene (PP), and polystyrene (PS) had the highest volatile matter content, with almost no ash and fixed carbon, while polyethylene terephthalate (PET) had high carbon content but low hydrogen content. Bones and vegetables had the highest ash content, while nutshells and rubber had the highest fixed carbon content. Paper and starch food had the highest oxygen content, and wool and bones had the highest nitrogen and sulfur content. Polyvinyl chloride (PVC) had the highest chlorine content at about 55%. PE, PP, and PS had the highest heating value, followed by chemical products such as rubber and chemical fiber. Conversely, paper, vegetables and bones had the lowest heating value. The results of cluster analysis of MSW components showed that fruit peel, weeds, wood, bamboo, leaves and nutshells could be classified as the lignocellulose category; starch food, cotton, toilet paper, printing paper and cardboard could be classified as the glucose monomer category; wood and chemical fiber could be classified as the high nitrogen and sulfur category; and PE, PP, and PS could be cluster as the polyolefin category.

Implications: The yield of municipal solid waste (MSW) is constantly increasing and waste to energy (WTE) has been used extensively all over the world. During the processes of incineration, pyrolysis, or gasification, the impact of physical and chemical properties of MSW is of great significance. However, the traditional classification of MSW is too general to provide more detailed information in many investigations. It is necessary to perform the investigation of characteristics of combustible MSW to distinguish different categories of MSW and find out their subclassification.     

垃圾渗滤液物化处理研究

采用物化处理方法对垃圾渗滤液进行处理,反应时间为1 h,进水的pH为7,出水的pH调至12,澄清后的pH调节到7～8,试验结果表明,COD的浓度从7452 mg/L降低到67 mg/L,去除率达到99.1%;TN的浓度从1055 mg/L降低到637 mg/L,去除率达到40%;TP的浓度从13.2 mg/L降低到未检出,去除率达到100%;色度从2048倍降低到1倍;除TN以外,COD、TP和色度均可达到国家规定的排放标准.     

城市生活垃圾与园林废弃物的共热解特性

为实现城市生活垃圾减量化、无害化和资源化,采用热重分析天平和实验室固定床热解反应器进行城市生活垃圾（MSW）与园林废弃物共热解实验,研究了不同热解终温、松树枝和柳树枝添加比例对热解产物产率影响,并利用气质联用色谱分析仪（GC-MS）对热解油进行表征分析。实验结果表明：MSW、松树枝和柳树枝的热解过程均可以分为3个阶段,主要包括脱水、热解、炭化;MSW、松树枝和柳树枝单独热解时最大失重速率分别出现在321.48、358.23和377.83℃;MSW与松树枝共热解DTG曲线在热解反应第2阶段有2个析出峰,分别在342.32℃和471.48℃,比MSW单独热解时,失重率增加了7.29%。当城市生活垃圾与松树枝、柳树枝的添加量分别为3：1时,热解液体产物产率明显升高,热解油中醇类、羧酸类、醛类等含氧有机物的含量降低,热值增加,热解油中氧含量降低,且松树枝对共热解焦油的脱氧效果更为显著,热解油品质得到提升。     

Prediction for energy content of Taiwan municipal solid waste using multilayer perceptron neural networks

In the past decade, the treatment amount of municipal solid waste (MSW) by incineration has increased significantly in Taiwan. By year 2008, approximately 70% of the total MSW generated will be incinerated. The energy content (usually expressed by lower heating value [LHV]) of MSW is an important parameter for the selection of incinerator capacity. In this work, wastes from 55 sampling sites, including villages, towns, cities, and remote islands in the Taiwan area, were sampled and analyzed once a season from April 2002 to March 2003 to determine the waste characteristics. The LHV of MSW in Taiwan was predicted by the multilayer perceptron (MLP) neural networks model using the input parameters of elemental analysis and dry- or wet-base physical compositions. Although all three of the models predicted LHV values rather accurately, the elemental analysis model provided the most accurate prediction of LHV values. Additionally, the wet-base physical composition model was the easiest and most economical. Therefore, the waste treatment operators can choose the more appropriate analysis method considering situations themselves, such as time, equipment, technology, and cost.     

Greenhouse gas emission potential of the municipal solid waste disposal sites in Thailand

Open dumping and landfilling are the prevalent solid waste disposal practices in Thailand. Surveys on the disposal sites revealed the presence of 95 landfills and 330 open dumps. Methane emission potential at these sites was estimated by three methods. Results of the Intergovernmental Panel on Climate Change (IPCC) method, Landfill Gas Emission model (LandGEM), and closed flux chamber technique were compared. The methane emission potential of 366 Gg/yr using the IPCC method was higher than the estimations of the LandGEM and closed flux chamber method of 115 Gg/yr and 103 Gg/yr, respectively. An understanding of the methane emission potential initiated the analysis of upgrading the open dumps into landfills, adding landfills to meet the future needs and utilization of landfill gases. Upgrading the open dumps to landfills increased the methane emission rates and their utilization potential. Approximately 20 additional landfills may be required to meet future demands. Landfill gas (LFG) utilization appears to be feasible in the large-scale landfills.     

市政污泥与生活垃圾混烧技术验证

对市政污泥与生活垃圾混烧进行了验证研究。结果表明,与生活垃圾单独焚烧相比,污泥与生活垃圾混烧后烟气中NOx、CO和HCl的浓度没有出现明显变化,而SO2浓度出现了下降（从82～93mg／m3下降至41～70mg／m3）;Hg、Pb、Sn、Cr和Zn的浓度均表现为不同程度的上升,但仍然符合GB[g485;二恶英从0．0087μgTEQ／m3降至O．0047μgTEQ／m3。掺烧半干污泥比例为10％、12％和15％时,吨物质的发电量分别为311．8kWh／t、306．7kWh／t和296．1kwh／t。混烧污泥在一定程度上降低了系统的发电量,因此建议混烧污泥的比例不应大于15％。测算的污泥混烧成本约209元／t（80％含水率）。     

市政污泥与生活垃圾混烧技术验证简

对市政污泥与生活垃圾混烧进行了验证研究。结果表明,与生活垃圾单独焚烧相比,污泥与生活垃圾混烧后烟气中NO_x、CO和HCl的浓度没有出现明显变化,而SO₂浓度出现了下降（从82~93 mg/m³下降至41~70 mg/m³）;Hg、Pb、Sn、Cr和Zn的浓度均表现为不同程度的上升,但仍然符合GB18485;二恶英从0.0087 ng TEQ/m³降至0.0047 ng TEQ/m³。掺烧半干污泥比例为10%、12%和15%时,吨物质的发电量分别为311.8 kWh/t、306.7 kWh/t和296.1 kWh/t。混烧污泥在一定程度上降低了系统的发电量,因此建议混烧污泥的比例不应大于15%。测算的污泥混烧成本约209元/t（80%含水率）。     

生活垃圾堆肥工艺条件及其反应动力学研究

为了改善堆肥微环境 ,提高生活垃圾堆肥速率 ,研究堆肥工艺条件及其反应动力学是非常必要的。通过控制堆肥工艺条件 ,如初始温度、含水率、C/N比及堆料颗粒大小 ,研究生活垃圾堆肥过程中生物、化学及物理因素的变化。试验结果表明 ,生活垃圾堆肥反应符合一级反应动力学 ;合理控制堆肥初始反应条件 ,能明显提高堆肥效率。     

城市生活垃圾降解率分析研究

针对城市生活垃圾降解率研究不足的现状,结合室内物理模拟实验,对垃圾温度和垃圾降解率的变化规律进行分析研究。研究结果表明,填埋初期垃圾填埋体温度升高较快,服从三次曲线变化规律;温度对垃圾降解率有重要的影响,单一温度下垃圾降解率随时间变化近似符合微生物生长曲线;不同温度下,温度高,垃圾降解率快,试验证明41.00、45.00℃垃圾降解率最快,垃圾降解率相差不大,可以认为温度高于41.00℃时垃圾降解率可以按照41.00℃时垃圾降解率计算。     

产物循环对生活垃圾好氧生物处理过程的影响

为研究产物循环对生活垃圾好氧生物处理过程中水分去除的影响,进行了不同的产物循环接种比例(30%、10%、无接种)的好氧生物处理实验.结果表明,产物循环接种可提高垃圾中各生物化学组分(总糖、脂类、蛋白质和木质纤维素类)及有机物总体的降解率;接种 30% 和 10% 产物组的有机物降解率分别为 70%和 65%,高于无接种组的 63%;接种组的高温(50℃以上)维持时间亦明显延长.产物循环接种对提高水分去除具有不确定性,接种率 30%、10%和无接种时,相应的水分去除率分别为 60%、61%和 62%,单位重量原料的水分去除量为 0.401、0.428和 0.421 kg/kg,产物最终含水率为 60%、59%和55%.     

Formation and emission status of PCDDs/PCDFs in municipal solid waste incinerators in Korea

This study was carried out to examine the formation and the emission status of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs) in the flue gases of commercial-scale municipal solid waste (MSW) incinerators, and thus to provide the engineering data for the reduction of PCDDs/PCDFs emitted from MSW incinerators. The formation concentrations of the PCDDs/PCDFs generated at the outlet of waste heat boilers (WHB) were in the range of 1.18-29.61 ng-TEQ/N m3 (average 5.75 ng-TEQ/N m3), while the emission concentrations at the stacks were in the range of 0.026-4.548 ng-TEQ/N m3 (average 0.924 ng-TEQ/N m3). Two major 2,3,7,8-substituted congeners were 2,3,4,7,8-PeCDF and 2,3,4,6,7,8-HxCDF, and their concentrations were up to 50% and 64% of total TEQ values at the outlet of WHB and the stack, respectively. From the results of multi-regression analysis, the formation concentration of PCDDs/PCDFs could be predicted as follows with the correlation factor of r2 = 0.962: PCDDs/PCDFs (ng-TEQ/N m3) = 3.036 (Cl) + 0.094 (T1) - 0.472 (Combustibles) + 0.059 (CO) - 0.039 (THC) - 3.366 (H) + 22.157, where T1 (degrees C) is the temperature at the outlet of the WHB. Cl, Combustibles and H are given as percentages and the others are in parts per million.     

电化学氧化法深度处理垃圾焚烧发电厂沥滤液生化出水

垃圾焚烧发电厂的沥滤液经生化处理后,COD和色度等仍然较高,达不到排放标准,必须进一步进行深度处理。采用自制的箱式四通道电化学反应器对垃圾焚烧发电厂沥滤液生化出水进行深度处理,研究了主要工艺参数——电流密度、表观流速、初始Cl^-浓度、比电极面积等因素对COD和色度去除效果的影响。适宜处理条件为：电流密度20 mA/cm²,反应器内表观流速2.92 cm/s,初始Cl^-浓度4 732 mg/L、比电极面积43.4 m²/m³。在此条件下处理废水10 min,色度就能达到排放要求,处理2 h,COD也能达到排放要求。考察反应器的能耗发现,电化学处理的能耗随电化学处理时间的延长呈不断增大的趋势。     

SBR法处理垃圾填埋场新鲜渗滤液的实验研究

采用SBR渐减曝气工艺处理模拟城市生活垃圾填埋场新鲜渗滤液,实验研究了反应器运行条件与出水水质的关系及有机碳的转移规律。研究结果表明新鲜渗滤液经24h曝气处理后,出水COD浓度约为500mg/L,BOD5/COD降为014左右;出水COD浓度与容积负荷无明显相关性;COD去除率与容积负荷呈正比,并在容积负荷为50kgCOD/m3·d时达到最高,约95%;去除的有机碳气相转化率与容积负荷呈正比,在容积负荷为50kgCOD/m3·d时,有机碳气相转化率接近100%;该系统最高容积负荷为50kgCOD/m3·d,相应的污泥浓度(以混合液悬浮性挥发固体(MLVSS)计)为712g/L。     

Remedial strategies for municipal solid waste management in China

The purpose of this investigation is to evaluate the current status and to identify the problems of municipal solid waste (MSW) management in China to determine appropriate remedial strategies. This is the second of two papers proposed on this topic. Major problems or difficulties identified in MSW management in China include MSW land, air, and water pollution, commingled collection, poor administration, shortage of funds, lack of facilities, and problems of training and public awareness. In order to solve these problems and to improve MSW management in China, remedial strategies in three areas are recommended: institutional reform, technology development, and legislation and administrative improvement. The primary principle involved in institutional reform is unifying legislative responsibilities into one body and developing a market mechanism for handling MSW. Composting, landfills, and incineration should be equally developed in accordance with China's needs. The feasibility of developing technology to handle MSW in China is discussed. Also recommended is the establishment of sound regulatory systems, including a service fee system, a source separation system, and a training program. China is presently undergoing economic and institutional reform at the national and local levels. Results of this study will provide useful information on MSW management in China.     

Subregion districting analysis for municipal solid waste collection privatization

Privatization of municipal solid waste (MSW) collection can improve service quality and reduce cost. To reduce the risk of an incapable company serving an entire collection area and to establish a competitive market, a large collection area should be divided into two or more subregions, with each subregion served by a different company. The MSW subregion districting is generally done manually, based on the planner's intuition. Major drawbacks of a manual approach include the creation of a districting plan with poor road network integrity for which it is difficult to design an efficient collection route. The other drawbacks are difficulty in finding the optimal districting plan and the lack of a way to consistently measure the differences among subregions to avoid unfair competition. To determine an MSW collection subregion districting plan, this study presents a mixed-integer optimization model that incorporates factors such as compactness, road network integrity, collection cost, and regional proximity. Two cases are presented to demonstrate the applicability of the proposed model. In both cases, districting plans with good road network integrity and regional proximity have been generated successfully.