Using enriched stable isotope technique to study Cu bioaccumulation and bioavailability in Corbicula fluminea from Taihu Lake,China

In this study, we measured trace metals (Cd, Cr, Cu, Ni, Pb, and Zn) in water and sediment from representative sites of Taihu Lake, with focus on the analysis of trace metal accumulation in Corbicula fluminea (bivalve). The results showed that the quality of water in Taihu Lake was generally good and the correlation was not found between Cu bioaccumulation in C. fluminea and the concentration in water and sediment. Thus, using the stable isotope tracer method, we studied Cu uptake from the water phase, the assimilation of Cu from the food phase, and the efflux of Cu in vivo by C. fluminea. The result revealed that this species exhibited a relatively lower efflux rate constant of Cu compared with other zoobenthos species. Using a simple bioenergetics-based kinetic model, Cu concentrations in the C. fluminea were calculated with the measured efflux rate. We put forward a novel method, which was taking the influence of biological kinetic on metal bioaccumulation into account to explain the field survey data.     

Experimental and modeling study of de novo formation of PCDD/PCDF on MSW fly ash

The effect of sulfur dioxide （SO2） on the formation of polychlorinated dibenzo-p-dioxins （PCDDs） and polychlorinated dibenzofurans （PCDFs） has been studied in an entrained-flow reactor （EFR） under simulated waste combustion conditions. A chlorination model based on conditional probability was employed to evaluate the homologue patterns of PCDDs and PCDFs. Results revealed that the presence of SO2 did not alter the formation pathway although SO2 suppressed PCDD/F formation. The prediction model of PCDF showed good agreement with the experimental data （R--0.95）, whereas the prediction for PCDDs did not correlate well with the experimental data. This may be explained because potential chlorination pathways play a significant role in PCDF formation, whereas PCDDs are mainly formed through condensation reactions. Furthermore, the result indicated that the steric hindrance during formation has more effects on PCDD than on PCDF due to the symmetric molecular structures of PCDDs.     

车载储氢瓶泄漏及车库内通风方式研究

为研究车库内燃料电池汽车氢气意外泄漏后的浓度分布情况,采用ANSYS软件,通过分析可燃性气体体积、水平方向和垂直方向氢气的扩散分布、不同泄漏位置氢气的扩散情况,研究6种不同通风方式对氢气意外泄漏扩散分布的影响,针对车库内氢气泄漏的特性,在通风方式上引入侧墙底部送风和侧墙顶部送风方式。研究结果表明：底部送风能显著加快氢气的扩散和排出。垂直高度上氢气浓度分布不均,侧墙顶部送风能使顶部堆积的氢气向下扩散,降低最大气体浓度;在墙角泄漏会由于墙壁的影响导致氢气堆积,对墙角局部通风尤为重要。研究结果可为氢燃料电池汽车专用车库的通风设计提供重要参考。     

沥青固化城市生活垃圾焚烧飞灰的实验研究

对利用沥青固化城市生活垃圾焚烧飞灰的处理效果进行了实验研究.探讨了沥青与飞灰以不同比例混合对飞灰重金属Pb,Cr,Cd,Ni,Cu,Zn固化效果的影响.并对沥青与飞灰的质量比(mAS mFA,其中AS代表沥青,FA代表飞灰)为0 2时作了进一步的研究,在此基础上加入不同比例的添加剂S和NaOH.结果表明,在沥青与飞灰的混合物中再加适当比例的添加剂,对飞灰的固化效果大大提高.     

煤粉炉联产贝利特-Q相水泥熟料及其水化性能试验

选用长广煤为试验煤种,分析纯CaO、MgO为添加剂,在两段多相反应实验台开展联产Q相水泥熟料试验.同时,对熟料样品矿物组成进行XRD、SEM和EDS分析,并对联产获得的Q相水泥熟料样品开展水化强度、膨胀性、安定性、凝结时间和水化性能等测试.结果表明,熟料样品矿物组成主要为2CaO·SiO2、Q相和3CaO·3Al2O3.CaSO4等;Q相水泥熟料样品砂浆试样各龄期抗压强度和抗折强度接近于32.5强度等级普通硅酸盐水泥标准,当Q相水泥熟料中掺加30%的硅酸盐水泥熟料时,其砂浆试样各龄期抗压强度和抗折强度达到32.5强度等级普通硅酸盐水泥标准要求;Q相水泥熟料样品膨胀性、安定性和凝结时间符合国家水泥相关标准;除2CaO·SiO2外,联产Q相水泥熟料水化3d就出现2CaO·Al2O3·8H2O、3CaO·Al2O3·3CaSO4·32H2O、xCaO·SiO2·yH2O和Al2O3·3H2O水化产物,且随着水化龄期的延长,2CaO·Al2O3·8H2O、3CaO·Al2O3·CaSO4·12H2O、3CaO·Al2O3·6H2O等水化产物逐渐增多,显示出良好的水化性能.     

尿素湿法烟气同时脱硫脱氮反应热力学分析

利用热力学原理计算出尿素湿法烟气同时脱硫脱氮、石灰湿法脱硫、亚硫酸铵湿法脱氮吸收反应达到平衡时SO2 和NOX的分压力 ,结果表明 :尿素作吸收剂湿法烟气同时脱硫脱氮是可行的 ,脱硫效果好于石膏法 ,脱氮效果好于亚硫酸铵法 ,而且几乎 1 0 0 %的最大限度地脱除烟气中的SO2 和NOX。     

脉冲电晕放电协同烟气脱硫脱硝试验研究

脉冲电晕放电对PM2.5具有一定的凝并作用,与直流静电除尘器相结合可以提高燃煤电厂烟气中粉尘的脱除效率.基于脉冲电晕放电还可以将烟气中的NO、SO2氧化成NO2、SO3等易吸收的物质成分,与传统的液相吸收洗涤技术相结合可提高NO、SO2的脱除效率.文中进行了脉冲电晕放电协同烟气脱硫脱硝的试验研究,研究了影响NO、SO2转化效率的主要因素.实验结果表明,提高脉冲峰值电压、脉冲频率、脉冲放电电极数目.延长停留时间.降低气体初始浓度有助于提高NO、SO2的转化效率;增加空气湿度可以显著提高SO2的转化效率.在本试验中,当NO、SO2初始浓度为150×10-6左右时,其相应的转化效率可以分别达到70%、90%.     

Effects and mechanisms of meta-sodium silicate amendments on lead uptake and accumulation by rice

The objectives of this research were to study the effects of Na₂SiO₃ application on the uptake, translocation, and accumulation of Pb in rice and to investigate the mechanisms of Pb immobilization by Na₂SiO₃ in paddy rice soils and rice plants. Pot experiments were conducted using a Cd-Pb-Zn-polluted soil and Oryza sativa L. ssp. indica cv. Donglian 5. L₃-edge X-ray absorption spectroscopy was used to identify Pb species in soils and roots. The results showed that the application of Na₂SiO₃ increased soil pH and available soil Si but decreased DTPA-extractable Pb in the soil. High dose of Na₂SiO₃ (12.5 g/kg) reduced the Pb level in brown rice as it inhibited Pb transfer from soil to rice grains, especially Pb transfer from the root to the stem. The Pb X-ray absorption near-edge spectroscopic analysis revealed that application of high dose of Na₂SiO₃ increased Pb-ferrihydrite and PbSiO₃ precipitates in the soil and in the root while it reduced Pb-humic acids (Pb-HAs) in the soil and Pb-pectin in the root. The decrease in Pb availability in the soil can be partly attributed to increase the precipitation of PbSiO₃ and the association of Pb²⁺ with Fe oxides in the soil. The inhibition of the root-to-stem translocation of Pb was partially due to the precipitation of PbSiO₃ on the root surfaces or inside the roots.     

甘河着生藻类群落结构及其与环境因子的关系

2018年8月(丰水期),在嫩江支流甘河,调查了19个点位的着生藻类群落结构和水环境特征。并运用聚类分析、Mcnaughton优势度分析和IBD(biological diatom index,硅藻生物指数)3种方法研究了甘河着生硅藻群落结构和优势种清洁状况,使用主成分分析、Spearman相关分析和冗余分析等统计分析方法研究了甘河着生硅藻群落和环境因子的响应关系。结果表明:甘河共鉴定出着生藻类90种(属),以硅藻门、绿藻门和蓝藻门为主,生物量丰富。丰水期甘河水生态环境质量状况较为健康,着生硅藻主要由清洁种构成,其中Achnanthidium minutissimum优势度0.48,为绝对优势种。聚类分析结果表明,甘河采样点位可分为3组;其中组1和组2点位主要位于甘河上、中游,上、中游水质、生境质量较好,健康程度较高,优势种均为清洁种,上游Achnanthidium minutissimum优势度达到了0.64;组3点位均位于甘河下游,下游人为干扰较强,健康程度较其余两组偏低,Nitzschia palea和Nitzschia paleaeformis等耐污种在组3的优势度较高。导致甘河着生硅藻群落清洁度由上游到下游逐渐变差的主要水环境因子为电导率、总磷和高锰酸盐指数,其中影响中游硅藻群落结构变化的主要水环境因子为高锰酸盐指数,影响下游硅藻群落结构变化的主要水环境因子为电导率和总磷。由此可见,着生硅藻群落可以较好的指示甘河流域水体有机污染程度和营养富集程度。     

城市污水处理厂污泥处理处置的政策分析

简要介绍了城市污水处理厂污泥处理处置技术，提出污泥产业发展政策的建议，指出土地利用是符合我国国情的污泥处置的方向之一：污泥处理技术主要有减量化、浓缩、脱水、消化、堆肥等；污泥处置技术主要有焚烧、填埋、土地利用、建材利用等。污泥处理处置应按照减量化、稳定化、无害化原则，鼓励污泥资源化综合利用。合理确定污水处理厂污泥处理处置设施的布局和设计规模；鼓励对污泥处理处置给与税、费优惠政策，明确将污泥处理处置的运营费用列入污水排污收费范围，建立科学的价格补偿机制；政府在污泥产业发展中起着较为重要的作用，主要体现为服务与监督，包括承诺、保障和协调三个方面。