光合细菌对铜绿微囊藻生长的抑制效应

为了探讨光合细菌对水华藻类的控制作用,在实验室条件下,通过菌藻共同培养,研究了沼泽红假单孢菌(Rhodopseudomonas palustras)、球形红细菌(Rhodobacter sphaeroides)及其混合培养物对铜绿微囊藻(Microcystis aeruginosa)生长的抑制效应.实验结果表明,光合细菌混合培养物对铜绿微囊藻抑藻作用最强,培养5 d时,铜绿微囊藻生物量降低率达58.9%,培养时间、培养温度、菌体投加量及培养基pH值等对光合细菌混合培养物的抑藻作用均有不同程度的影响.光合细菌混合培养物发挥抑藻作用的适宜条件为培养温度25℃,培养时间≤5 d,光合细菌投加量(V_(光合细菌菌悬液):V_(藻培养液)=1:80),藻培养基pH为8.0左右.     

Relationships of nitrous oxide fluxes with water quality parameters in free water surface constructed wetlands

The effects of chemical oxygen demand (COD) concentration in the influent on nitrous oxide (N₂O) emissions, together with the relationships between N₂O and water quality parameters in free water surface constructed wetlands, were investigated with laboratoryscale systems. N₂O emission and purification performance of wastewater were very strongly dependent on COD concentration in the influent, and the total N₂O emission in the system with middle COD influent concentration was the least. The relationships between N₂O and the chemical and physical water quality variables were studied by using principal component scores in multiple linear regression analysis to predict N₂O flux. The multiple linear regression model against principal components indicated that different water parameters affected N₂O flux with different COD concentrations in the influent, but nitrate nitrogen affected N₂O flux in all systems.     

生态系统健康分析指标体系构建

以生态学理论为基础,基于压力-状态-响应结构模型建立生态系统健康分析指标体系,首次引入水资源密度和空气污染指数两个指标,采用层次分析法确定各单因子指标权重,并用加权叠加法对生态系统健康进行综合分析。以网格作为基本分析单元,运用RS&GIS技术及统计学方法,建立系统化定量化的方法体系。并以山西省为案例,对其进行分析评价,为山西省生态环境保护提供科学依据。     

基于互相关算法的人员密集场所人群运动速度特征研究

研究人群密集场所的人群运动速度特征可以预测人群的运动趋势,在大型活动组织过程中可以对异常人群运动做出预警,避免过度的拥挤及踩踏事件的发生,保证大型群体性活动的安全顺利开展。利用国内某重要城市核心区公共场所人群运动的视频图像,通过互相关算法提取该场所人群的运动速度,并进一步比较通往景区的四条不同路径上人群运动速度的差异性,分析其人群运动特征。分析结果表明单向通道的人群运动速度较大且运动方向基本与通道的两侧边界平行,而双向通道中由于人群中阻尼效应的影响,人群运动速度的大小和方向都发生了不同程度的改变。分析结果可为核心区管理者进行大型群体性活动的组织、人群疏散与引导提供建议,进而为人群拥挤踩踏事故风险防控、拥挤踩踏事故专项应急预案制定及人群聚集活动安全方案编制提供理论支持。     

铝和锆改性沸石对太湖底泥-水系统中溶解性磷酸盐的固定作用

通过试验方法考察了2种不同底泥改良剂(铝和锆改性沸石)对太湖底泥-水系统中SRP(可溶解性磷酸盐)的固定作用. 改性沸石改良前后太湖底泥对水中较高浓度磷的吸附平衡数据可用Langmuir和Freundlich等温吸附方程进行描述,吸附动力学过程可用准二级动力学模型进行描述. 太湖底泥、铝和锆改性沸石改良太湖底泥的最大磷吸附量分别为395、613和1 009 mg/kg. 被改良太湖底泥中,铝改性沸石所吸附的磷主要以NaOH-rP(NaOH提取态磷)形态存在,锆改性沸石所吸附的磷主要以NaOH-rP和Res-P(残渣态磷)形态存在. 当水中初始ρ(SRP)很低时,太湖底泥和改性沸石改良太湖底泥均释放出磷,其中后者的释磷量较低. 改性沸石改良太湖底泥中的w(BAP)(BAP为生物有效磷)低于太湖底泥,w(liable-P)(liable-P为弱吸附态磷)也明显偏低. 铝改性沸石改良太湖底泥中的w(BD-P)(BD-P为氧化还原敏感态磷)与太湖底泥相比差异不显著,而锆改性沸石改良太湖底泥中的w(BD-P)明显低于太湖底泥. 可见,铝和锆改性沸石均可用于控制太湖底泥磷的释放,其中锆改性沸石的控制效果更好.      

Effects of Al3+ on pollutant removal and extracellular polymeric substances (EPS) under anaerobic,anoxic and oxic conditions

The highest removal efficiencies of COD and TN were achieved under 10 mg/L of Al³⁺. The highest TP removal efficiency occurred under 30 mg/L of Al³⁺. EPS, PS and PN concentrations increased with the addition of Al³⁺. Sludge properties significantly changed with the addition of Al³⁺. Aluminum ions produced by aluminum mining, electrolytic industry and aluminum-based coagulants can enter wastewater treatment plants and interact with activated sludge. They can subsequently contribute to the removal of suspended solids and affect activated sludge flocculation, as well as nitrogen and phosphorus removal. In this study, the effects of Al³⁺ on pollutant removal, sludge flocculation and the composition and structure of extracellular polymeric substances (EPS) were investigated under anaerobic, anoxic and oxic conditions. Results demonstrated that the highest chemical oxygen demand (COD) and total nitrogen (TN) removal efficiencies were detected for an Al³⁺ concentration of 10 mg/L. In addition, the maximal dehydrogenase activity and sludge flocculation were also observed at this level of Al³⁺. The highest removal efficiency of total phosphorus (TP) was achieved at an Al³⁺ concentration of 30 mg/L. The flocculability of sludge in the anoxic zone was consistently higher than that in the anaerobic and oxic zones. The addition of Al³⁺ promoted the secretion of EPS. Tryptophan-like fluorescence peaks were detected in each EPS layer in the absence of Al³⁺. At the Al³⁺ concentration of 10 mg/L, fulvic acid and tryptophan fluorescence peaks began to appear, while the majority of protein species and the highest microbial activity were also detected. Low Al³⁺ concentrations (<10 mg/L) could promote the removal efficiencies of COD and TN, yet excessive Al³⁺ levels (>10 mg/L) weakened microbial activity. Higher Al³⁺ concentrations (>30 mg/L) also inhibited the release of phosphorus in the anaerobic zone by reacting with PO₄^3-.     

烟草对砷的吸收累积特征及其健康风险研究

以福建省主栽烟草品种翠碧1号、K326和云烟87为材料,在外源砷添加量为0、10、20、40、70和100 mg·kg~(-1)的土壤中进行盆栽试验,探讨砷对烟草的毒害效应以及砷在土壤-烟草体系中的迁移累积特征,并对植烟土壤中砷的安全临界值进行计算。结果表明,在砷毒害下,烟草生长受到抑制,且烟草根系生长受抑制程度最强。随着砷添加量的增加,土壤中有效砷含量和烟草各部位砷含量均显著提高(P 0.05),砷在根系中的含量最高,在茎中的含量最低。砷处理下各部位间的转移系数表现为TF_((茎-叶)) TF_((土-根)) TF_((根-茎)),且外源砷的增加促进砷从茎到叶片中转移。38.28%～74.37%的砷富集在烟草根部,上部叶中砷的富集量最少(4.61%～11.7%),且所研究的3个烟草品种中翠碧1号对砷的富集能力最强。根据通过吸烟进入人体砷的限量以及土壤有效砷含量与烟草中部叶砷含量的回归模型,推算出翠碧1号、K326和云烟87的植烟土壤有效砷的安全临界值分别为14.17、14.31和11.86 mg·kg~(-1)(磷酸二氢钠浸提)。并将福建省植烟土壤有效砷的安全临界值拟定为11.86 mg·kg~(-1)(磷酸二氢钠浸提)。本研究结果为福建省烟草安全生产提供一定技术指导。     

The influence of slope collapse on water exchange between a pit lake and a heterogeneous aquifer

Slope collapse will reduce the water exchange. Slope collapse will affect the spatial distribution of the water exchange. Precipitation have the most impact on the dynamics of the water exchange. Due to the increase in open pit mining, pit lakes have become common surface water features, posing a potential risk to subsurface aquifer. In this study, a pit lake–groundwater interaction model is built based on the general program MODFLOW with the LAK3 package. For the first time, the effects of lake-slope collapse and aquifer heterogeneity on pit lake–groundwater interactions are analyzed by dividing the lake into six water exchange zones based on the aquifer lithology and groundwater level. Our investigation and simulations reveal a total water exchange from groundwater to the lake of 349000 m³/a without collapse of the pit lake slope, while the total net water exchange under slope collapse conditions is 248000 m³/a (i.e., a reduction of 1.40-fold). The monthly net water exchange per unit width from groundwater to the lake reaches the largest in April, shifting to negative values in zone IV from June to August and in zone V in June and July. Moreover, the monthly net water exchange per unit width decreases from north to south, and the direction and magnitude of water exchange are found to depend on the hydraulic gradients between the lake and groundwater and the hydraulic conductivity of the slope collapse.     

基于全生命周期管理的固体废物分类资源化利用研究

梳理我国固体废物资源化利用现状,剖析当前固体废物在处理机制、管理思路和方式、协同处置等方面问题,基于全生命周期理论、绿色循环及低碳发展思路和方法,开展固体废物分类资源化全生命周期优化管理,提出工业生产制造环节须开展绿色生态设计、推行清洁生产;流通消费环节须构建绿色供应链、倡导绿色消费生活方式;回收处置环节须探索新型商业模式、加大重点领域重点品种固体废物资源化科技创新。     

资源产业集聚对资源型城市经济增长的影响--基于夜间灯光数据的实证研究

在资源依赖背景下,发挥好资源产业集聚的正向作用,是资源型城市实现经济可持续增长的关键。基于2005—2017年山西省11个地级市面板数据,采用校正整合的夜间灯光数据度量城市经济增长,并运用系统广义矩估计法(SYS-GMM)检验了资源产业集聚对城市经济增长的影响。结果表明:资源产业集聚对资源型城市经济增长影响显著,呈“先上升,后下降”的倒“U”型关系,在资源产业集聚初期将推动城市经济增长,但过度集聚反而会抑制经济增长。