用累托石吸附处理含铁(Ⅲ)废水

用累托石作吸附剂处理有色金属厂冶炼过程中产生的含Fe(Ⅲ)废水。在废水pH为7．5～8．5、反应时间为30min、累托石投加量为12g／L的条件下,Fe(Ⅲ)质量浓度可由5mg／t．降到0．08mg／L,Fe(Ⅲ)的去除率最高为98．4％,外排废水符合GB8978--1996一级标准。对Fe(Ⅲ)进行等温吸附实验,其等温吸附曲线符合Langmuir模型,其吸附机理主要是吸附作用和沉淀作用。     

硫酸锰废渣浸出毒性及淋溶特性研究

长沙市兴镇13家硫酸锰厂的生产废渣使当地的生态环境造受到了严重破坏。本文在废渣浸出毒性实验、渣柱淋滤实验以及废渣的全分析基础上,全面地研究了废渣的组成、浸出毒性大小以及在当地酸沉降条件下的淋滤特征,为其安全处置提供了理论基础。研究证明,废渣中重金属种类多、含量高,尤其是锰,高达138800mg/kg。渣的浸出毒性虽未达到国家规定的危险废物鉴别标准,但远超过了《污水综合排放标准》,其衰减可用负指数方程来描述。在酸雨淋溶下,渣中的锰离子会在短时期内大量释放后,维持在一相对较低水平长期释放,对环境威胁巨大。     

厌氧折流板反应器处理生活污水的运行特性

以厌氧消化污泥作为厌氧折流板反应器ABR的接种污泥,研究恒温(35℃)条件下ABR处理生活污水的启动和运行特性。实验结果表明,ABR反应器仅用了39 d就完成初次启动,COD去除率一直稳定在60%左右。在以后运行的5个阶段里,即当水力停留时间为4~10 h,容积负荷为1.17~2.9 kg COD/m3.d,反应器对COD的平均去除率基本稳定在70.49%~80.2%;并且当HRT=7 h,VRL=1.612 kg COD/m3.d时,反应器对COD的去除率平均高达80.2%,平均COD出水低于100 mg/L。在实验过程中(除启动阶段外),反应器出水碱度均远远大于进水碱度,VFA均在1.5 mmol/L以下。     

双齿许水蚤(Pseudodiaptomus dubia)对亚热带虾池Cu和Zn的富集

重金属污染是对虾养殖环境主要污染现象之一,查明重金属在环境中的迁移规律对养殖水质调控和对虾健康养殖具有重要意义.本文采用火焰原子吸收分光光度计测定在不同暴露时间下双齿许水蚤(Pseudodiaptomusdubia)对Cu和Zn的富集量,研究了双齿许水蚤对Cu和Zn富集动力学,并探讨了温度和盐度对其富集的影响.结果表明:双齿许水蚤对Cu和Zn的富集过程均经历了快速、慢速和平衡3个阶段,实验24h达到富集平衡;双齿许水蚤对Cu和Zn的富集动力学参数k1(Cu)=0.077＜k1(zn)=0272,BCF(cu)=0.344＜BCFZn)=2.252,双齿许水蚤对Zn的富集速率和富集能力均大于Cu.温度对双齿许水蚤Cu和Zn富集的影响显著(p＜0.05),最适温度范围为15 ～30℃;盐度对双齿许水蚤Zn富集的影响极显著(p＜0.01),而对Cu富集的影响不显著(p＞0.05),对Cu和Zn适宜的富集盐度范围为10 ～35.这些研究结果说明,双齿许水蚤对Cu和Zn均具有较强的富集能力,在对虾养殖期间,应通过循环过滤设施去除受到重金属污染池塘中的浮游动物,减少幼虾对其摄食和虾体中重金属的积累量,从而降低食品安全隐患.     

The theory behind,and the challenges of,conserving nature's stage in a time of rapid change

Most conservation planning to date has focused on protecting today's biodiversity with the assumption that it will be tomorrow's biodiversity. However, modern climate change has already resulted in distributional shifts of some species and is projected to result in many more shifts in the coming decades. As species redistribute and biotic communities reorganize, conservation plans based on current patterns of biodiversity may fail to adequately protect species in the future. One approach for addressing this issue is to focus on conserving a range of abiotic conditions in the conservation‐planning process. By doing so, it may be possible to conserve an abiotically diverse “stage” upon which evolution will play out and support many actors (biodiversity). We reviewed the fundamental underpinnings of the concept of conserving the abiotic stage, starting with the early observations of von Humboldt, who mapped the concordance of abiotic conditions and vegetation, and progressing to the concept of the ecological niche. We discuss challenges posed by issues of spatial and temporal scale, the role of biotic drivers of species distributions, and latitudinal and topographic variation in relationships between climate and landform. For example, abiotic conditions are not static, but change through time—albeit at different and often relatively slow rates. In some places, biotic interactions play a substantial role in structuring patterns of biodiversity, meaning that patterns of biodiversity may be less tightly linked to the abiotic stage. Furthermore, abiotic drivers of biodiversity can change with latitude and topographic position, meaning that the abiotic stage may need to be defined differently in different places. We conclude that protecting a diversity of abiotic conditions will likely best conserve biodiversity into the future in places where abiotic drivers of species distributions are strong relative to biotic drivers, where the diversity of abiotic settings will be conserved through time, and where connectivity allows for movement among areas providing different abiotic conditions.