干法腈纶生产废水脱氨氮研究

采用本实验室富集驯化的高效硝化细菌对生化处理后的干法腈纶生产废水进行了脱NH3-N研究,在连续运行装置中考察了DO和MLSS的变化特征,并研究了废水NH3-N负荷和COD负荷对脱NH3-N效果的影响.实验结果表明:该菌能适应干法腈纶生产废水中的难生物降解物质并有效去除废水中的NH3-N,启动期DO呈现"高-低-高"的变化,运行期污泥增长速率呈现"S"型变化;进水NH3-N负荷达到0.405 kg/(m3·d)时仍能维持出水P(NH3-N)在5 mg/L以下,进水COD负荷由0.126 kg/(m3·d)提高到0.975 kg/(m3·d)的过程中,NH3-N去除率始终高于96%.     

Modification of Fe–Mn mixed oxide COS removal sorbent by rare-earth oxides addition

In order to develop highly active sorbent for COS removal, Fe–Mn mixed oxides doped with CeO₂, La₂O₃ or Sm₂O₃ were studied. The effects of these promoters on the structural properties of Fe–Mn oxides were investigated by XRD, BET, TPR and TEM techniques. XRD results revealed that the degree of crystallinity of Fe–Mn oxide phase decreased due to the addition of rare-earth oxides. Doping with CeO₂, La₂O₃ or Sm₂O₃ led to an increase in BET surface area of the sample. TPR studies showed that the reactivity of the reduction of doped samples increased in the temperature range of 300–450 °C. In addition, the desulfurization test was performed at 325 °C with a gas hourly space velocity of 1000 h⁻¹. It was found that the addition of 3% La₂O₃ greatly improved the absorption sulfur capacity of the sorbent, while the sorbent doped 3% CeO₂ achieved a sufficiently high purifying degree before breakthrough.     

CO2 emission driving forces and corresponding mitigation strategies under low-carbon economy mode: evidence from China’s Beijing–Tianjin–Hebei region

On account of the background of China’s “new normal” characterized by slower economic growth, this paper analyses the low-carbon economy status quo in the Beijing–Tianjin–Hebei region and empirically investigates the relationship between carbon dioxide (CO₂) emissions and its various factors for China’s Beijing–Tianjin–Hebei region using panel data econometric technique. We find evidence of existence of Environmental Kuznets Curve. Results also show that economic scale, industrial structure, and urbanization rate are crucial factors to promote CO₂ emissions. However, technological progress, especially the domestic independent research and development, plays a key role in CO₂ emissions abatement. Next, we further analyze the correlation between each subregion and various factors according to Grey Relation Analysis. Thereby, our findings provide important implications for policymakers in air pollution control and CO₂ emissions reduction for this region.     

太原市土壤六六六和滴滴涕的暴露格局及健康风险

为研究六六六(HCHs)和滴滴涕(DDTs)在太原市不同功能区土壤中的暴露格局、来源以及对周围人群的健康风险,在太原市化工区、灌区、矿区、生态区周边荒地土壤中进行采样,分析测定了土壤中HCHs和DDTs含量,根据太原市人群实际情况的暴露参数和USEPA的部分参数,对土壤HCHs和DDTs的健康风险进行评价。结果表明:1)太原市表层土壤中HCHs的平均含量大小依次为化工区>灌区>矿区>生态区;DDTs平均含量的大小依次为化工区>灌区>矿区>生态区,仅6%的HCHs和3%的DDTs和的平均残留水平均高于我国土壤质量标准一级标准,但均不超过二级标准值;2)土壤中HCHs残留主要源于历史上林丹的使用,DDTs残留则来源于历史和新污染源的共同影响;3)太原市表层土壤HCHs和DDTs致癌风险大小为化工园区>矿区>灌区>生态区。非致癌风险大小为化工区>矿区>灌区>生态区。3种暴露途径的在不同功能区的健康风险贡献率大小均为经口摄入>呼吸吸入>皮肤接触;综合来看太原市表层土壤中的HCHs和DDTs并未对人类造成非致癌风险,但有一定的致癌风险。本文的研究结果可为太原市土壤质量评价和环境污染防治提供科学指导,并对太原市人群的健康风险防治提供依据。     

A dynamic modelling of nutrient metabolism in a cyclic activated sludge technology (CAST) for treating low carbon source wastewater

Environmental Science and Pollution Research - A new mathematical model incorporating biopolymer kinetics and the process of the simultaneous storage and growth are established for the treatment of...     

Spatial variation and toxicity assessment for heavy metals in sediments of intertidal zone in a typical subtropical estuary (Min River) of China

Environmental Science and Pollution Research - Sediment samples were collected in five marshes (C1, Phragmites australis marsh; C2, P. australis and Cyperus malaccensis marsh; C3, C. malaccensis...     

Removal of sulfamethoxazole and sulfapyridine by carbon nanotubes in fixed-bed columns

Sulfamethoxazole (SMX) and sulfapyridine (SPY), two representative sulfonamide antibiotics, have gained increasing attention because of the ecological risks these substances pose to plants, animals, and humans. This work systematically investigated the removal of SMX and SPY by carbon nanotubes (CNTs) in fixed-bed columns under a broad range of conditions including: CNT incorporation method, solution pH, bed depth, adsorbent dosage, adsorbate initial concentration, and flow rate. Fixed-bed experiments showed that pH is a key factor that affects the adsorption capacity of antibiotics to CNTs. The Bed Depth Service Time model describes well the relationship between service time and bed depth and can be used to design appropriate column parameters. During fixed-bed regeneration, small amounts of SMX (3%) and SPY (9%) were irreversibly bonded to the CNT/sand porous media, thus reducing the column capacity for subsequent reuse from 67.9 to 50.4 mg g^?1 for SMX and from 91.9 to 72.9 mg g^?1 for SPY. The reduced column capacity resulted from the decrease in available adsorption sites and resulting repulsion (i.e., blocking) of incoming antibiotics from those previously adsorbed. Findings from this study demonstrate that fixed-bed columns packed with CNTs can be efficiently used and regenerated to remove antibiotics from water.     

Sources of Fine Particulate Species in Ambient Air over Lake Champlain Basin,VT

Abstract

This study is a part of an ongoing investigation of the types and locations of emission sources that contribute fine particulate air contaminants to Underhill, VT. The air quality monitoring data used for this study are from the Interagency Monitoring of Protected Visual Environments network for the period of 2001–2003 for the Underhill site. The main source-receptor modeling techniques used are the positive matrix factorization (PMF) and potential source contribution function (PSCF). This new study is intended as a comparison to a previous study of the 1988–1995 Underhill data that successfully revealed a total of 11 types of emission sources with significant contributions to this rural site. This new study has identified a total of nine sources: nitrate-rich secondary aerosol, wood smoke, East Coast oil combustion, automobile emission, metal working, soil/dust, sulfur-rich aerosol type I, sulfur-rich aerosol type II, and sea salt/road salt. Furthermore, the mass contributions from the PMF identified sources that correspond with sampling days with either good or poor visibility were analyzed to seek possible correlations. It has been shown that sulfur-rich aerosol type I, nitrate aerosol, and automobile emission are the most important contributors to visibility degradation. Soil/dust and sea salt/road salt also have an added effect.     

A-O工艺污泥疏水比率与污泥活性的关系

通过A-O工艺对印染废水的降解处理,研究了不同污泥活性下微生物疏水比率和COD去除率的变化规律.结果表明,污泥活性指标ATP浓度与微生物疏水性之间存在一定关系,并对COD去除率产生一定的影响.缺氧污泥的活性指标ATP浓度在0.38～0.77 mg/L范围时,污泥微生物的疏水性最好且疏水比率最高值为84％,COD的去除率最高,为70.01％;好氧污泥的活性指标ATP浓度在0.86～2.17 mg/L范围时,污泥微生物的疏水性最好,疏水比率最高值为75％,COD的去除率最高为96.2％.     

改进的TLI指数法及其在巢湖营养状态评价中的应用

对巢湖2000—2008年的监测数据运用SPSS做统计分析,得出叶绿素a与总氮、总磷和透明度的相关系数。通过得出的权重结果,分析出与26个湖泊的差异性,构建了改进的综合营养状态指数(TLI)评价方法,并提出评价的4个步骤。以巢湖为例,运用该方法对湖泊的营养状态进行评价,且对巢湖的富营养化程度做了年际和年内变化的综合评价,评价结果显示各营养物指标的相关关系在近30年有了较大变化,巢湖的富营养化现象已日益严重,已从轻度富营养化状态转变为中度富营养化状态。