Combined effects of titanium dioxide and humic acid on the bioaccumulation of cadmium in Zebrafish

The combined effects of titanium dioxide (TiO₂) nanoparticles and humic acid (HA) on the bioaccumulation of cadmium (Cd) in Zebrafish were investigated. Experimental data on the equilibrium Cd bioaccumulation suggest that only the dissolved Cd effectively contributed to Cd bioaccumulation in HA solutions whereas both the dissolved and TiO₂ associated Cd were accumulated in TiO₂ or the mixture of HA and TiO₂ solutions, due likely to the additional intestine uptake of the TiO₂-bound Cd. The equilibrium Cd bioaccumulation in the mixed system was comparable to that in the corresponding HA solutions, and significantly lower than that in the corresponding TiO₂ solutions (n = 3, p < 0.05). The presence of either HA or TiO₂ (5-20 mg L⁻¹) in water slightly increased the uptake rate constants of Cd bioaccumulation whereas combining HA and TiO₂ reduced the uptake rate constants.     

曝气强度对同时硝化反硝化（SND）脱氮过程中N2O排放的影响

为了控制污水脱氮中N2O排放,在不同曝气强度下研究了好氧硝化段同时硝化反硝化（SND）系统的N2O排放特性,并采用PCR—DGGE技术分析微生物群落特征。结果发现,随着曝气强度的增强,系统总氮去除率下降,但脱氮中N2O—N所占比例则上升,实验中从低到高3个曝气强度下,总氮去除率分别为80．01％、65．28％和58．62％,脱氮中N2O—N所占的比例为1．89％、7．84％和9．20％。PCR—DGGE分析显示,和低曝气强度下相比中、高曝气强度下系统微生物群落发生明显变化,但中曝气强度和高曝气强度下系统微生物群落表现出较高相似性。这表明,不同曝气强度下系统N2O排放受到氮素转化和微生物群落变化的影响。适宜曝气强度不仅提高总氮去除率,还可有效控制N2O排放。     

Historical Analysis of SO<Subscript>2</Subscript> Pollution Control Policies in China

Coal is not only an important energy source in China but also a major source of air pollution. Because of this, China’s national sulfur dioxide (SO₂) emissions have been the highest in the world for many years, and since the 1990s, the territory of China’s south and southwest has become the third largest acid-rain-prone region in the world. In order to control SO₂ emissions, the Chinese government has formulated and promulgated a series of policies and regulations, but it faces great difficulties in putting them into practice. In this retrospective look at the history of SO₂ control in China, we found that Chinese SO₂ control policies have become increasingly strict and rigid. We also found that the environmental policies and regulations are more effective when central officials consistently give environmental protection top priority. Achieving China’s environmental goals, however, has been made difficult by China’s economic growth. Part of this is due to the practice of environmental protection appearing in the form of an ideological “campaign” or “storm” that lacks effective economic measures. More recently, better enforcement of environmental laws and regulations has been achieved by adding environmental quality to the performance assessment metrics for leaders at all levels. To continue making advances, China needs to reinforce the economic and environmental assessments for pollution control projects and work harder to integrate economic measures into environmental protection. Nonetheless, China has a long way to go before economic growth and environmental protection are balanced.     

A/O-膜生物反应器和A~2O系统中有机物分子量分布的对比研究

采用凝胶过滤色谱(GPC)对A/O-膜生物反应器(A/O-MBR)和A2O系统中有机物分子量分布进行了对比研究.结果表明,A/O-MBR系统中由进水到好氧滤液的有机物分子量分布依次变宽,其趋势恰好与A2O系统相反;A/O-MBR好氧滤液的有机物分子量分布远宽于A2O好氧滤液.A/O-MBR好氧滤液中重均分子量(Mw)＞107 u的有机物占总有机物质量的3.4%,表明正是由于膜的截留作用导致这类大分子有机物在MBR中的累积,而无法像A2O系统一样随出水流走;A/O-MBR系统各段污泥混合液的胞外聚合物(EPS)的分子量分布较分散,说明A/O-MBR系统中微生物新陈代谢产物多,并在膜的截留作用下最终造成了这些产物在膜表面大量的沉积.     

改性火山岩滤料去除矿井水中铁锰离子影响因素研究

以改性火山岩滤料作为除铁除锰的滤料,通过对模拟矿井水的过滤试验,研究了滤速、pH值、滤层厚度及铁锰离子浓度对其除铁除锰效率的影响。结果表明：改性火山岩滤料能实现模拟矿井水中Mn²⁺的100%去除,效果明显优于未改性火山岩;最为合理的过滤滤速为7～8 m/h;除铁除锰的过程主要发生在滤层厚度为90 cm的上部滤层中;随着铁锰浓度的升高,改性火山岩滤料除铁的效率变化很小,除锰效率呈快速、线性降低;中性或偏碱性的环境有利于改性火山岩滤料充分发挥高效吸附去除能力。     

不同回流比对无植物垂直流人工湿地除氮效果的影响

通过内碳源前置反硝化脱氮工艺试验,比较了不同回流比对垂直流人工湿地除氮效果的影响。试验结果表明,TN去除率随着回流比增加而增加,NH⁺₄-N去除率则随着回流比的增加先降低后增加的趋势,两者去除率之和以回流比200％为最高,以回流比150％次之,以回流比100％为最低。从TN的去除率来看,回流比150％略高于回流比200％。     

大规模突发事件应急物资调度的过程模型

指出现有关于应急物资调度文献的不足,给出大规模突发事件的定义;结合我国近年来几起大规模突发事件总结出该事件的特征;分析大规模突发事件应急物资调度的特征,从应急物资的调度准备、调度实施、调度评估3个阶段进行设计并解释了大规模突发事件应急物资调度的全过程模型。该模型为大规模突发事件应急物资调度决策提供理论依据和方法指导,对当今的公共安全和社会稳定具有重要价值和现实意义。     

“博戈罗茨克”国际应急演练

时间：2009年5月19-22日 地方：俄罗斯联邦莫斯科州诺金斯克市179训练基地 行动：上合组织“博戈罗茨克”民防救灾演练 主题：实施破坏性地震救援和其他应急救灾行动     

影响侧沟式膜泥法一体化OCO工艺脱氮效率的因素研究

采用侧沟式膜泥法一体化OCO工艺处理模拟生活污水,考察了DO、HRT和C/N 3种影响因素对模拟生活污水脱氮的效果。研究结果表明：在好氧区DO为2 mg/L左右、HRT=12 h、C/N为7.5左右时,具有较理想的脱氮效果,TN去除率达到了80%;试验还表明本工艺具有较强的抗冲击负荷能力。     

染料废水生物膜中酶的作用特性与条件优化

通过对兼氧-好氧染料废水处理系统兼氧生物膜中脱氢酶、脂肪酶和酯酶的活性分析,研究了3种酶的作用特性以及最佳条件优化。试验结果表明,脱氢酶作为一种胞内酶,在出水水样中仍能检测到2.2%的活性存在;82.5%脂肪酶和79.9%的酯酶分布在生物膜中,这说明绝大多数脂肪酶和酯酶是与细胞相连或固定在细胞外多聚絮体基质中。0.4 mmol/L的抑制剂EDTA对脱氢酶活性有促进作用,而对脂肪酶和酯酶的抑制率分别达到59.8%和18.9%。正交试验结果表明,待测3种酶有最大活性的条件均为：温度为60℃,底物浓度为50 μmol/L,pH为8,在优化条件下待测酶活性可达常规作用条件的2.58～6.44倍。各因素对待测酶活性的影响强弱排序为：温度>底物浓度>pH。