Drivers of microbial beta-diversity in wastewater treatment plants in China

As one of the most well-documented biogeographic patterns, the distance-decay relationship provides insights into the underlying mechanisms driving biodiversity distribution. Although wastewater treatment plants (WWTPs) are well-controlled engineered ecosystems, this pattern has been seen among microbial communities in activated sludge (AS). However, little is known about the relative importance of environmental heterogeneity and dispersal limitation in shaping AS microbial community across China; especially they are related to spatial scale and organism types. Here, we assessed the distance-decay relationship based on different spatial scales and microbial phylogenetic groups by analyzing 132 activated sludge (AS) samples across China comprising 3,379,200 16S rRNA sequences. Our results indicated that the drivers of distance-decay pattern in China were scale-dependent. Microbial biogeographic patterns in WWTPs were mainly driven by dispersal limitation at both local and national scales. In contrast, conductivity, SRT, and pH played dominant roles in shaping AS microbial community compositions at the regional scale. Turnover rates and the drivers of beta-diversity also varied with microorganism populations. Moreover, a quantitative relationship between dispersal limitation ratio and AS microbial turnover rate was generated. Collectively, these results highlighted the importance of considering multiple spatial scales and micro-organism types for understanding microbial biogeography in WWTPs and provided new insights into predicting variations in AS community structure in response to environmental disturbance.     

低温环境下人工湿地植物组配对养殖废水的处理效果研究

强化低温环境下人工湿地的污水处理能力,对于促进人工湿地的应用推广具有重要的意义。本研究利用绿狐尾藻(Myriophyllum aquaticum)和菖蒲(Acorus calamus L.)两种湿地植物,在室外低温环境下(＜15℃),研究人工湿地植物组配对不同负荷养殖废水的处理效应及关键影响因素。结果表明,在不种、单种和不同顺序混种绿狐尾藻(M.aquaticum)和菖蒲(A.calamus L.)处理下,菖蒲+绿狐尾藻组合湿地(AM)对TN、TP和COD去除率均为最高,在低负荷和高负荷环境下平均去除率分别为74.2%、71.3%、83.0%和67.3%、81.9%、75.3%。相较于空白对照和植物单种的湿地系统,植物混种系统的DO较高,且AM处理在低负荷和高负荷环境下均能保持较高的C∶N。根据Pearson相关性以及PCA分析,DO与TN、NH⁺₄-N去除率显著相关(P<0.05),C∶N与COD去除关联性最好。可见,菖蒲+绿狐尾藻植物组合可能通过改善DO和C∶N等湿地微环境条件来增强湿地对污染物的去除,能够作为低温环境下强化湿地对污染物去除的一种有效措施。     

Assessing the “design paradox” with life cycle assessment: A case study of a municipal solid waste incineration plant

One of the most important processes in an integrated waste management system is incineration, which, among the different waste management disposal options still remains a critical waste treatment system. New dynamics and approaches have to be developed to embrace such a wide and complex topic, and better knowledge and assessment of incineration are strategically significant to define future environmental scenarios.Life cycle assessment (LCA), as a tool to optimise process-operating conditions and to support decision-making process, is often applied to investigate processes under design in various sectors, since choices made in the development phases can affect the future environmental profile. However, even if the greatest opportunity to improve a process from an environmental perspective is during the design phase, at the same time the knowledge is limited, in accordance with the so-called “design paradox”.Thus, in this context, this study used LCA methodology to quantitatively assess the extent to which the environmental impact of an incineration line reflects the environmental burdens perceived during the design phase. A comparative LCA was conducted at the design phase and under operating conditions at an Italian municipal solid waste incineration plant.The outcomes of the study indicated that for almost all of the categories analysed, the impacts associated with the process under design overestimated the impacts associated with the operating process, with the exception of climate change and water depletion. The results suggested that after the conduction of an LCA at the design phase of a process, an LCA of the operative conditions should be carried out to verify how much the over- or under-estimations affected the results.     

银纳米颗粒对黄菖蒲早期生长和生理特征的影响

N-AgNPs（银纳米颗粒）暴露对湿地植物的生长发育有重要影响,而N-AgNPs对大型湿地植物黄菖蒲（Iris pseudacorus）的影响尚不清楚.选取湿地植物黄菖蒲为受试物种,采用室内土培法分析柠檬酸钠包覆的N-AgNPs对黄菖蒲早期生长和生理特征的影响.结果表明:①不同ρ（N-AgNPs）〔分别为0、5、10、15、20 mg/L,依次记为N0（对照）、N5、N10、N15、N20〕处理和作用时间均会影响黄菖蒲生长和生物量积累.培养初期（0~14 d）,N5、N10处理会抑制黄菖蒲生长,而N15、N20处理会促进黄菖蒲生长;培养后期（14~35 d）,不同ρ（N-AgNPs）处理均抑制黄菖蒲生长.整个培养期内（0~35 d）,N5、N10处理均抑制黄菖蒲地上、地下生物量积累,而N20处理会促进黄菖蒲地上、地下生物量积累.②不同ρ（N-AgNPs）处理均降低了黄菖蒲叶绿素含量,提高了PSⅡ（光系统Ⅱ）反应中心的光能转换效率,降低了光氧化损伤的发生率;N5、N10、N15处理下黄菖蒲叶片PSⅡ功能反应中心的开放度降低、光合电子传递速率（ETR）变慢;N5和N20处理下黄菖蒲叶片光合电子传递活性（qP）增大,而N10和N15处理下光合电子传递活性降低.③各ρ（N-AgNPs）处理均显著降低了黄菖蒲叶片中的丙二醛含量,膜脂过氧化作用减弱;同时,增加了黄菖蒲叶片中w（脯氨酸）,对黄菖蒲产生较强的胁迫.研究显示,随着培养浓度的增加,ρ（N-AgNPs）对黄菖蒲生物量累积的影响由抑制作用变为促进作用;各ρ（N-AgNPs）处理均会降低黄菖蒲的叶绿素含量、增加w（脯氨酸）,对黄菖蒲的生长产生胁迫.      

施用污泥堆肥品对土壤和植物总汞及甲基汞的影响

采用田间试验,分别施加两种不同的污泥堆肥品(含生物质炭和不含生物质炭),研究污泥堆肥土地利用过程土壤及植物总汞和甲基汞变化情况、迁移转化特征和植物富集能力.结果表明,施加污泥堆肥品会引起土壤总汞和甲基汞含量升高,但总汞含量低于国家土壤环境质量二级标准.生物质炭堆肥品可能促进土壤汞的甲基化,但不同处理土壤甲基汞/总汞(Me Hg/THg)比值较低.植物成熟后不同处理植物总汞含量明显低于幼苗期,而甲基汞含量均高于幼苗期.施加两种堆肥品对植物富集总汞没有明显差异,但对甲基汞富集影响显著.施加生物质炭堆肥品的土壤甲基汞含量明显高于施加无生物质炭堆肥品的土壤,而植物甲基汞含量则相反.生物质炭的加入可能有利于土壤甲基汞形成,但不利于甲基汞的迁移,抑制植物对土壤甲基汞的富集.植物对甲基汞的富集能力较强(富集系数为1.24~14.63),需关注长期施肥带来的土壤环境汞生态风险.     

微曝气强化生态浮床去除水中Cu~(2+)效果研究

构建一种改进型微曝气强化生态浮床污水静态模拟实验平台,利用该平台研究了3种水生植物黄菖蒲、西伯利亚鸢尾和水竹对水中Cu~(2+)的去除能力及富集特征;同时探究了不同曝气量下,黄菖蒲微曝气生态浮床对水中Cu~(2+)的去除效果。结果表明:在实验条件下,3种水生植物对水中Cu~(2+)的去除能力依次为黄菖蒲>西伯利亚鸢尾>水竹;当曝气量为7.5 L/min时,黄菖蒲微曝气生态浮床对水中Cu~(2+)的去除效果最好;3种植物的不同部位对重金属Cu~(2+)的吸收富集能力均表现为根部最强。     

2015年中国城镇污水处理厂达标排放评估

基于2015年3364座中国城镇污水处理厂在线监测数据(小时级),借鉴欧盟排放标准达标评估方法,分析了不同维度条件下,城镇污水处理厂污染物排放达标率情况(日均值)。结果表明:按污水厂污染物全年日均值95%保证率,2015年全国城镇污水处理厂化学需氧量(COD)、氨氮(NH_3-N)排放达标率分别为94%、80%。从省份来看,天津、江西、河南、四川和山东COD达标率均为100%,天津、山东、江苏NH_3-N达标率分别为100%、95%和95%;从处理厂排入水体的类型来看,排入Ⅳ类、Ⅴ类水体的排口达标率较高,达到了97%以上。中国在线监测污水处理厂处理工艺主要为氧化沟、A~2/O、SBR,从污水处理工艺的达标率来看,氧化沟、A~2/O等工艺处理COD、NH_3-N效果较好。     

硫碳比对芦苇碳源-硫耦合表面流湿地脱氮的影响

针对农田退水中NO₃--N占比高、碳氮比低的问题,提出PS-SFW（Phragmites australis and sulfur combined surface flow constructed wetland,芦苇碳源-硫耦合表面流人工湿地）,对其强化农田退水脱氮的可行性进行了研究,并与SFW₀（无芦苇碳源-硫填充的常规表面流湿地）进行对比,重点研究了HRT（水力停留时间）为3、2、4 d条件下S/C（质量比,分别为0.32、0.56）对PS-SFW脱氮效能的影响.结果表明,HRT为3 d（第29~40天）时,PS-SFW_0.32（S/C比为0.32）、PS-SFW_0.56（S/C比为0.56）和SFW₀的w（NO₃--N）分别为55.9%±11.0%、66.0%±10.0%和7.0%±3.0%,w（TN）分别为36.9%±1.0%、40.3%±3.0%和4.5%±2.0%,PS-SFW_0.56对TN和NO₃--N去除效能高于PS-SFW_0.32,远高于SFW₀;HRT为4 d时（第41~81天）及HRT为3 d（第130~149天）时,PS-SFW_0.32、PS-SFW_0.56、SFW₀的w（NO₃--N）为66.3%±5.0%、90.5%±4.0%、14.4±4.0%和53.4%±3.0%、62.9%±10.0%、48.5%±5.0%,w（TN）为55.5%±5.0%、75.4%±5.0%、14.4%±3.0%和48.8%±2.0%、57.5%±6.0%、44.1%±5.0%,PS-SFW_0.56对NO₃--N和TN的去除效能均优于PS-SFW_0.32,并且优于SFW₀.HRT为2 d（第82~129天）时,PS-SFW_0.32、PS-SFW_0.56、SFW₀的w（NO₃--N）为47.7%±7.0%、46.6%±6.0%和26.8%±4.0%,w（TN）为37%±6.0%、36.6%±6.0%和24.0%±3.0%,PS-SFW_0.32、PS-SFW_0.56对氮的去除效能接近,但仍优于SFW₀.研究显示,PS-SFW运行条件应优选S/C为0.56、HRT为4 d.      

日本污水处理厂的监测探讨

探讨了日本滋贺县湖南中部净化中心化验室水质分析管理、在线仪表管理、监测数据分析利用和相关监测试验.介绍了化验室水质分析项目,常用水质分析仪器的维护管理,工艺在线仪表监测管理,以及常用在线仪表的维护管理等内容.揭示了溶解氧、氧化还原电位、五日生化需氧量污泥负荷、污泥龄、好氧污泥龄和PAC添加量等监测数据的综合分析利用有助于提高脱氮除磷效率和节约运行成本.指出相关监测试验是提升运行管理水平的重要手段.     

集中式污水厂重金属排放限值及其控制进展研究

介绍了中国集中式污水厂污水处理现状,主要包括污水厂进出水监测指标和进出水水质指标设计不足,重金属处理效果不明显;同时对国外污水处理现状以及重金属排放限值进行比较,探讨了中国污水处理厂污水中重金属排放限值及控制的问题,污水中重金属处理工艺未设计,进出水水质指标未将重金属指标纳入设计中,重金属排放限值远高于发达国家限值.结合现状分析,提出加强污水处理厂重金属源头控制与排放限值监管的相关建议,以确保排放水体的环境安全.