Effect of bio-column composed of aged refuse on methane abatement – A novel configuration of biological oxidation in refuse landfill

An experimental bio-column composed of aged refuse was installed around the exhaust pipe as a new way to mitigate methane in refuse landfill.One of the objectives of this work was to assess the effect of aged refuse thickness in bio-column on reducing CH 4 emissions.Over the study period,methane oxidation was observed at various thicknesses,5 cm (small size),10 cm (middle size) and 15 cm (large size),representing one to three times of pipeline diameters.The middle and large size both showed over 90% methane conversion,and the highest methane conversion rate of above 95% occurred in the middle-size column cell.Michaelis-Menten equation addressed the methanotrophs diffusion in different layers of the bio-columns.Maximum methanotrophic activity (V max) measured at the three thicknesses ranged from 6.4 × 10 3 to 15.6 × 10 3 units,and the half-saturation value (K M) ranged from 0.85% to 1.67%.Both the highest V max and K M were observed at the middle-size of the bio-column,as well as the largest methanotrophs population,suggesting a significant efficiency of methane mitigation happened in the optimum zone with greatest affinity and methanotrophic bacteria activities.Therefore,bio-column is a potential style for methane abatement in landfill,and the aged refuse both naturally formed and artificially placed in the column plays a critical role in CH 4 emission.     

高效反硝化菌和包埋填料性能及微生物群落分析

为考察高效反硝化细菌及其包埋填料对低温、低底物浓度的适应性和恢复性,实验采用2个条件(适宜、不利)、3个阶段(D_1、D_2、D_3),探究二者的反硝化能力,即:将初始适宜条件下培养的高效反硝化细菌[300 mg·(L·h)~(-1)]置于不利条件下运行(D_1),反硝化性能稳定后将其包埋,仍置于不利条件下运行(D_2),90 d后恢复到适宜条件(D_3).结果表明分别经过17d和16 d的运行,反硝化细菌和包埋填料在D_1、D_2阶段的速率最终稳定在5.4 mg·(L·h)~(-1)、4.8 mg·(L·h)~(-1),说明细菌及其包埋填料能够适应低温、低底物的不利条件;在D_3阶段发现,经过12 d运行填料的反硝化速率就可达到300mg·(L·h)~(-1),表明其具有快速的自我恢复能力.利用扫描电镜分析包埋填料的内外结构,发现其内外结构均利于细菌生长代谢和传质.高通量测序分析结果表明,D_2阶段的优势菌属仍为具有反硝化功能的Pseudomonas、Thauera、Gelidibacter,因而证明了细菌在不利条件的适应性;D_3阶段包埋填料的优势菌属Thauera、Petrimonas、Pseudomonas,与初始适宜条件下培养的高效反硝化细菌的优势菌属完全相同,这也充分证明了细菌包埋填料具有良好的恢复能力.     

新型覆土材料的CH_4氧化能力与N_2O释放能力

在垃圾卫生填埋处理技术中,覆土材料的选择对处理成本和技术都至关重要.探究了新型覆土材料(矿化垃圾+牛粪+木屑)的CH4氧化能力,并进一步分析了温度、含水率、初始φ(CH4)和好氧厌氧等环境因素对CH4氧化能力的影响.结果表明:1新型覆土中矿化垃圾的填埋龄不同,其CH4氧化能力也有所差异,填埋龄较久的覆土B(10 a)、C(15 a)在培养时间内对CH4去除率和氧化速率均明显高于覆土A(5 a);2当温度为30℃、含水率为35%时,新型覆土的CH4氧化能力最高;3用米歇尔-门坦方程表征CH4降解的过程,R2(相关系数)为0.993,CH4氧化速率最大值为5.21μmol/(g·h),半速常数为5.48%;4厌氧环境中新型覆土具有CH4氧化能力,而厌氧环境中CH4去除率相对好氧环境更慢,培养20 d后,厌氧环境CH4去除率为83%;5当土壤孔隙含水率分别为46%、70%时,覆土干湿交替导致的N2O和CO2释放量远小于CH4氧化量,故N2O增温效应可忽略.由矿化垃圾+牛粪+木屑组成的新型覆土材料的CH4氧化速率最大值比现有覆土材料高1~2个数量级,其可应用于不同类型填埋场,特别是降雨较多的南方垃圾填埋场,可有效减缓垃圾填埋气CH4的释放影响.     

水力负荷对矿化垃圾反应器处理渗滤液效果的影响

构建3个微曝气(0.1 L/min)矿化垃圾反应器进行渗滤液处理,研究较长时期内不同水力负荷对矿化垃圾处理渗滤液效果的影响。结果表明:随着水力负荷的增加,反应器对渗滤液中有机污染物和氮污染物的降解能力降低。在试验运行稳定阶段,水力负荷为28,42,56 L/(m3·d)时,COD平均去除率分别为88%、66%、56%;NH+4-N平均去除率分别为94%、90%、71%;TN平均去除率分别为52%、50%、45%。当水力负荷42 L/(m3·d)时出现NO-2-N累积现象,且水力负荷越大NO-2-N累积越严重。建议微曝气矿化垃圾反应器处理渗滤液过程中水力负荷不宜大于42 L/(m3·d)。     

皖东张八岭、珠龙地区西冷岩组微古植物群初步研究

皖东张八岭、珠龙地区西冷岩组为一套浅海相变质火山－沉积岩系，岩性以细碧－石英角斑岩为特征，出露面积约占总面积的80％，视厚度为4616.51m。笔者等在1：5万区域地质填图中对这套变质岩系进行了生物地层工作．并采集了大量的微占植物样品，从中获得了丰富的微古植物化石。按化石组合特征将其分为两个组合：第一组合主要产于拂晓园艺场－朱郢剖面冷岩组下部层位，包括有33个属44个种，其中1个新属，2个新种，19个未定种，3个相似种；第二组合产于西冷岩织上部层位的罗士城、邱庄、西徐等地，包括30个属．34个种．其小1个新种、18个未定种、13个相似种的化石。西冷岩组微古植物群而貌与我国青白口系的微古植物面貌比较相似．与前苏联上里菲（850－1050Ma）、澳大利亚小部苦泉组微古植物面貌相似。因此，将西冷岩组的时代归为广义的青白口纪较为合适。     

城市垃圾产生量预测研究

通过对城市生活垃圾产生状况的分析，选取我国西部和东部的典型城市成都、上海进行研究。运用线性回归模型对两城市垃圾量进行预测，为城市建设规划和垃圾综合处理提供依据。     

返青前后草地早熟禾草坪根际微生物区系动态

根际是土壤-植物生态系统物质及能量交换的活跃界面,根际微生物不仅直接影响植物对水分、养分的吸收,而且也同时影响植物对不良环境的抵抗能力。利用选择性培养基对草地早熟禾(PoapratensisL.)返青前后根际与非根际的细菌、真菌以及放线菌类群进行分离测数,拟从根际及非根际土壤微生物区系动态变化方面来阐述草地早熟禾返青前后其根际微生态的变化规律。结果表明:(1)草地早熟禾草坪的返青后,根际及非根际细菌、真菌数量明显增加,但放线菌数量呈减少趋势;(2)无论返青前后或者根际以及非根际,细菌的数量都占整个土壤微生物量的绝大部分,细菌数量的变化代表了整个微生物类群数量的变化趋势,使得草地早熟禾返青后根际土壤由"真菌型"向"细菌型"转化;(3)返青前后,各微生物类群都表现出明显的根际效应。     

矿化垃圾和土壤淋滤系统处理分散型餐饮废水

随着我国旅游业的迅猛发展,分散型餐饮废水的产生量也逐年增多。分散型餐饮废水的不合理处理处置对旅游区的生态环境造成了严重污染。以矿化垃圾作为基质材料来处理分散型餐饮废水,并对比了矿化垃圾和土壤淋滤系统对分散型餐饮废水的处理效果。结果表明:餐饮废水经矿化垃圾反应床连续运行21 d后,出水COD和氨氮分别为42,3.8 mg/L,COD和氨氮的去除率可达92.6%和77%以上。与土壤淋滤系统相比,矿化垃圾反应床的处理效果更为理想。     

Characterization of drug and alcohol use among senior drivers fatally injured in U.S. motor vehicle collisions, 2008–2012

Objective: Adults 65 years of age and older comprise the fastest growing demographic in the United States. As substance use is projected to increase in this population, there is concern that more seniors will drive under the influence of impairing drugs. The purpose of this analysis was to characterize the drug and alcohol usage among senior drivers fatally injured (FI) in traffic collisions.

Methods: Data from the Fatality Analysis Reporting System were analyzed from 2008 to 2012. Commonly used classes and specific drugs were explored. Rates of drug use, multiple drugs, concomitant drug and alcohol use, and alcohol use alone were generated using Poisson regression with robust error variance estimation. Rates were compared to a reference population of FI middle-aged drivers (30 to 50 years old) using rate ratios.

Results: Drug use among FI senior drivers occurred in 20.0% of those tested. Among drug-positive FI senior drivers, narcotics and depressants were frequent. The prevalence of testing positive for any drug, multiple drugs, combined drug and alcohol, and alcohol use alone among FI seniors were 47% less (relative risk [RR] = 0.53, 95% confidence interval [CI], 0.47, 0.62), 59% less (RR = 0.41, 95% CI, 0.34, 0.51), 87% less (RR = 0.13, 95% CI, 0.09, 0.19), and 77% less (RR = 0.23, 95% CI, 0.19, 0.28), respectively, compared to FI middle-aged drivers.

Conclusions: Though overall drug use is less common among FI senior drivers relative to FI middle-aged drivers, driving under the influence of drugs may be a relevant traffic safety concern in a portion of this population.     

矿化垃圾柱吸附能力预测模型

建立数学模型对矿化垃圾柱的吸附能力进行理论预测。通过改变模型参数得到矿化垃圾柱的不同吸附穿透曲线，分析穿透曲线的变化规律，判定参数的优劣，确定垃圾柱吸附运行最优工况。为矿化垃圾柱的设计提供一定的理论依据。