Characterization of the archaeal community fouling a membrane bioreactor

Biofilmformation, one of the primary causes of biofouling, results in reducedmembrane flux or increased transmembrane pressure and thus represents a major impediment to the wider implementation of membrane bioreactor (MBR) technologies for water purification. Most studies have focused on the role of bacteria in membrane fouling as they are the most dominant and best studied organisms present in the MBR. In contrast, there is limited information on the role of the archaeal community in biofilm formation in MBRs. This study investigated the composition of the archaeal community during the process of biofouling in an MBR. The archaeal community was observed to have lower richness and diversity in the biofilmthan the sludge during the establishment of biofilms at low transmembrane pressure (TMP). Clustering of the communities based on the Bray-Curtis similarity matrix indicated that a subset of the sludge archaeal community formed the initial biofilms. The archaeal community in the biofilm was mainly composed of Thermoprotei, Thermoplasmata, Thermococci, Methanopyri, Methanomicrobia and Halobacteria. Among them, the Thermoprotei and Thermoplasmata were present at higher relative proportions in the biofilms than they were in the sludge. Additionally, the Thermoprotei, Thermoplasmata and Thermococci were the dominant organisms detected in the initial biofilms at low TMP, while as the TMP increased, the Methanopyri, Methanomicrobia, Aciduliprofundum and Halobacteria were present at higher abundances in the biofilms at high TMP.     

建筑施工扬尘特征与监控指标

建筑施工活动引起的扬尘是我国城市空气颗粒物污染的重要来源,选择天津市一处典型的建筑施工工地作为研究对象,分施工阶段对环境空气PM10、尘源样品和降尘等进行了系统监测实验,得到了建筑扬尘的成分谱(元素、离子和碳组分)和尘源样品的粒径分布.结果表明,建筑施工扬尘的污染特点和化学组成特征与具体施工阶段、施工操作和建筑材料等密切相关.通过采集工地周边的降尘,发现利用降尘可以作为工地扬尘的监控指标.     

贵州省旱地黄壤Zn和有机质的空间异质性特征

探究黄壤Zn和有机质的空间分布特征及其变异规律,分析环境因子对黄壤Zn和有机质空间分异的影响,对贵州省山地复杂环境下土壤资源的科学管理和可持续利用具有重要意义.基于130914个野外采样点,综合运用多种地统计学与传统统计学的方法,分析了贵州省旱地黄壤Zn和有机质的空间变异特征及其驱动因子.结果表明：①贵州省旱地黄壤Zn的平均含量略低于全国土壤Zn的平均含量（100 mg·kg^-1）,处于中等水平,而有机质含量则较为丰富;变异系数表明两者均属于中等程度的空间变异.②黄壤Zn和有机质均存在显著的空间自相关性,呈聚集分布,其中以Zn的Moran''s I指数更大、自相关程度更强;两个养分的最优理论模型均为指数模型,且块基比均介于25%~50%,具有中等程度的空间相关性,但结构性因素的作用更大;有机质的分形维数较Zn要高,其空间格局更复杂,对尺度的依赖性大.③Zn的高值区主要集中在西部和西北部地区,低值区多位于东南部和南部地区;有机质高值区沿西北东南带斜线分布,而低值区则沿东北西南方向与高值区呈现交叉分布的格局.④空间自相关分析和方差分析表明,选取的7个环境因子均对黄壤Zn和有机质的空间变异具有不同程度的影响,其中,高程和NDVI与两者的相关性更强.     

黄河三角洲湿地研究进展

从湿地研究内容和研究方法两方面,回顾了近10年来黄河三角洲湿地研究的成果。在这10年间,黄河三角洲湿地研究的内容和范围明显拓宽,主要研究内容包括湿地修复、湿地评价、湿地管理等。研究方法日趋先进成熟,模型模拟、遥感动态监测及3S等新技术和方法得到广泛应用。文章在分析黄河三角洲湿地的研究现状和特点的基础上,对未来研究趋势和热点进行了展望,认为未来黄河三角洲湿地的研究重点应在湿地演化机制与恢复、湿地对环境变化的响应与反馈、湿地动态监测、湿地保护技术等方面。     

水动力条件对藻类影响的研究进展

水动力过程是影响水体富营养化状态和水华爆发的重要因素,水动力因素对藻类影响的研究对于富营养化水体藻类控制具有重要意义。归纳分析近年来关于流速、流态对藻类生长和种类变化的研究报道;就水动力条件对藻类的影响及其作用机理等详细地进行了文献综述。水动力条件对藻类生长的影响分为流速和流态两个方面,不论是单一藻种还是混合藻类,低流速、小扰动有利于藻类的生长和聚集,流速增大则导致Chla浓度先递增后递减,不同藻类的临界流速并不相同;藻类生长随着湍流程度的增加而逐渐受到抑制,抑制作用与水流流态（层流、过渡流、湍流）无明显相关关系,水体流态的变化造成水流剪应力的变化,藻类种类的差异导致其对水流剪应力的响应变化。水动力条件变化引起的藻类种群结构变化,主要表现为水体混合加剧导致优势种群的转换。水动力条件对藻类影响的作用原理主要是引起了光强的改变、细胞长度的变化、营养盐运送及捕食行为变化等。综观当前的研究成果,水动力能否真正阻止藻类细胞的生长或聚集,影响藻类生长或种类变化的扰动的最低水平以及水动力对藻类影响的作用机理是这一领域未来研究的重点所在。     

Investigating the impact of air pollution on AMI and COPD hospital admissions in the coastal city of Qingdao,China

• The impact of air pollution on AMI/COPD hospital admissions were examined. • Significant connection was found between air pollutants and AMI/COPD in Qingdao. • Nonlinearity exists between air pollution and AMI/COPD hospital admissions. Air pollution has been widely associated with adverse effects on the respiratory and cardiovascular systems. We investigated the relationship between acute myocardial infarction (AMI), chronic obstructive pulmonary disease (COPD) and air pollution exposure in the coastal city of Qingdao, China. Air pollution in this region is characterized by inland and oceanic transportation sources in addition to local emission. We examined the influence of PM_2.5, PM₁₀, NO₂, SO₂, CO and O₃ concentrations on hospital admissions for AMI and COPD from October 1, 2014, to September 30, 2018, in Qingdao using a Poisson generalized additive model (GAM). We found that PM_2.5, PM₁₀, NO₂, SO₂ and CO exhibited a significant short-term (lag 1 day) association with AMI in the single-pollutant model among older adults (>65 years old) and females, especially during the cold season (October to March). In contrast, only NO₂ and SO₂ had clear cumulative lag associations with COPD admission for females and those over 65 years old at lag 01 and lag 03, respectively. In the two-pollutant model, the exposure-response relationship fitted by the two-pollutant model did not change significantly. Our findings indicated that there is an inflection point between the concentration of certain air pollutants and the hospital admissions of AMI and COPD even under the linear assumption, indicative of the benefits of reducing air pollution vary with pollution levels. This study has important implications for the development of policy for air pollution control in Qingdao and the public health benefits of reducing air pollution levels.     

人工湿地中试系统基质中藻类组成的研究

从2003年3月到2004年2月，在水力负荷为600mm／d的条件下研究了人工湿地中试系统（medium scale plot，MSP）基质中藻类的组成．结果表明，栅藻、小球藻、盘星藻、空星藻、纤维藻、舟行藻、小环藻、平裂藻和颤藻属的一些种类在下行池基质各层不同季节均有出现，下行池表层藻类较丰；上行池基质中不同季节的藻类组成中念珠藻和鱼腥藻均为固氮种类，菱板藻、舟行藻和卵形藻属的一些种类在上行池表层出现较多，上行池藻类组成较下行池少．本实验探讨了在人工湿地基质中存在的藻类组成，为湿地除藻机理和评估系统的稳定性提供参考．图1表2参10     

高固体条件下黑水添加对厨余垃圾厌氧发酵的影响

为探究高固体条件下黑水添加对厨余垃圾厌氧发酵性能的影响,设置了不同黑水添加比例以及不同接种比的发酵实验。结果表明,实验初期各组均出现了快速酸化,调节pH至7.3~7.5并添加缓冲剂后,产甲烷过程逐步恢复正常;添加了黑水的混合发酵实验组的累计甲烷产量相比厨余垃圾单独发酵实验组提升不大,而黑水的添加比例较高时,由于氨抑制作用,造成产甲烷量下降了46.7%;接种比由1下降至0.5时,混合比为3∶1和厨余垃圾单独发酵的实验组累计甲烷产量分别下降了73.2%和38.3%,平均甲烷含量分别下降了47.7%和13.0%。说明高固体、低接种比条件下,加入黑水不能有效改善厨余垃圾的厌氧发酵反应。该研究结果可为高负荷条件下厨余垃圾与黑水2种高浓度家庭有机废物流的资源化处理提供理论参考。     

曝气生物滤池与地下渗滤系统工艺脱氮除磷

以生活污水为研究对象,考查了曝气生物滤池和地下渗滤系统组合工艺脱氮除磷的性能。工艺运行过程中,曝气生物滤池只考虑COD和氨氮的去除,把总氮和总磷的去除分离到地下渗滤系统中。实验结果表明,曝气生物滤池和地下渗滤系统组合工艺有良好的脱氮除磷能力。滤速为0.6 m·h-1,气水比为5：1,反冲洗周期为7 d时,曝气生物滤池达到最佳运行状态,对COD、氨氮、TN、TP的去除率分别达到85.3%、83.5%、30%、56%。为了提高TN、TP的去除率,地下渗滤系统采用间歇的方式运行,每个周期连续进水12 h,放空12 h,进水为曝气生物滤池出水,水力负荷为5 cm·h-1,对COD、氨氮、TN、TP的去除率分别达到41.3%、62.8%、81.3%、82%。     

生物塘-人工湿地工艺去除农田灌溉水中镉污染的效果

通过野外大田试验,探讨了生物塘-人工湿地工艺去除农田灌溉水中Cd污染的效果,并进一步分析了水力停留时间对Cd净化效果的影响及净化效果的日变化规律。结果表明:试验区灌溉水中全量Cd平均浓度为13.92 μg/L,是GB 5084—2005《农田灌溉水质标准》中Cd浓度限值的1.39倍,且以溶解态Cd为主,约占77.8%;经生物塘-人工湿地工艺处理后全量Cd平均去除率为42.0%,出水达标天数率为85.2%;组合工艺的Cd去除率随水力停留时间的延长呈先升高后降低趋势,最佳停留时间约为19 h;生物塘和人工湿地的Cd去除率日变化规律均呈早晚低、中午高的单峰曲线,Cd最大去除率出现在13:00左右。