废水处理生物出水中COD构成的解析——以焦化废水为例

以焦化废水为例,采用连续过滤及化学分析的方法考察了悬浮组分、胶体组分及溶解组分对生物出水残余COD的贡献,并结合紫外-可见光谱和GC/MS图谱定性解析各形态组分的有机构成特征,构建了一种废水生物出水COD构成解析的评价方法.实验结果显示,焦化废水生物处理出水中悬浮态和胶体态组分对残余COD的贡献分别占COD总量的25.9%—46.3%和18.7%—44.4%,建议优先考虑采用混凝沉淀工艺去除约35.0%—45.0%的COD,使处理出水基本能够达标排放;溶解组分的COD占COD总量的24.6%—40.7%,其中4.3%—15.8%的COD由硫化物、硫氰化物等还原性物质贡献,其余部分主要由链状烃类、酯类及醇类等溶解有机组分贡献,建议采用氧化或吸附工艺进行处理,以满足更高的出水水质要求.     

广州大气气溶胶总悬浮颗粒物（TSP）中的有机示踪化合物

为了解广州市气溶胶中有机示踪化合物的分布特征,采用N,O-双（三甲基硅烷基）三氟乙酰胺（BSTFA）衍生化预处理技术和GC/MS分析技术,于2002—2003年对广州市大气气溶胶中的有机示踪化合物进行了定性和定量分析.结果表明,脱水糖类、β-谷甾醇、脱氢松香酸主要来源于生物质燃烧;葡萄糖、果糖、蔗糖、海藻糖等主要来源于土壤的再悬浮;藿烷类、甾烷类化合物主要来源于化石燃料的燃烧;胆甾醇可以作为肉类烹饪等餐饮源的有机示踪物.广州市大气中所检测到的所有糖类化合物与植物蜡的浓度比值春、秋两季较高,这可能与春天是植物叶片扩张和耕耘播种的季节、秋天是果实成熟和农作物收割的季节有关.     

TRANSIENT STORAGE ASSESSMENTS OF DYE‐TRACER INJECTIONS IN RIVERS OF THE WILLAMETTE BASIN,OREGON1

ABSTRACT: Rhodamine WT dye‐tracer injections in rivers of the Willamette Basin yield concentration‐time curves with characteristically long recession times suggestive of active transient storage processes. The scale of drainage areas contributing to the stream reaches studied in the Willamette Basin ranges from 10 to 12,000 km². A transient storage assessment of the tracer studies has been completed using the U.S. Geological Survey's One‐dimensional Transport with Inflow and Storage (OTIS) model, which incorporates storage exchange and decay functions along with the traditional dispersion and advection transport equation. The analysis estimates solute transport of the dye. It identifies first‐order decay coefficients to be on the order of 10^?5/sec for the nonconservative Rhodamine W.T. On an individual subreach basis, the first‐order decay is slower (typically by an order of magnitude) than the transient storage process, indicating that nonconservative tracers may be used to evaluate transient storage in rivers. In the transient storage analysis, a dimensionless parameter (A_s/A) expresses the spatial extent of storage zone area relative to stream cross section. In certain reaches of Willamette Basin pool‐and‐riffle, gravel‐bed rivers, this parameter was as large as 0.5. A measure of the storage exchange flux was calculated for each stream subreach in the simulation analysis. This storage exchange is shown subjectively to be higher at higher stream discharges. Hyporheic linkage between streams and subsurface flows is the probable physical mechanism contributing to a significant part of this inferred active transient storage. Hyporheic linkages are further suggested by detailed measurements of river discharge with an Acoustic Doppler Current Profiler system delineating zones in two large rivers where water alternately enters and leaves the surface channels through gravel‐and‐cobble riverbeds. Measurements show patterns of hyporheic exchange that are highly variable in time and space.     

Real-time wet scavenging of major chemical constituents of aerosols and role of rain intensity in Indian region

Real-time simultaneous studies on chemical characteristics of rainwater and PM₁₀ aerosols were carried out to understand the scavenging of major chemical components in Indian region. The concentrations of Ca²⁺, NH₄⁺, SO₄²⁻ and NO₃⁻ were observed to be lower in the aerosol samples collected during rain as compared to before and after rain events. The most significant reduction was noticed for Ca²⁺ (74%) during rain which showed highest scavenging ratio (SR) and indicated that below-cloud scavenging is an effective removal process for Ca²⁺ in Indian region. Among non-sea salt components, Ca²⁺ had highest SR at Hyderabad indicating typical characteristics of crustal influence as abundance of calcium carbonate in soil dust has been reported in India. However, the levels of these major chemical components gradually got build-up in due course of time. After rain events, the levels of SO₄²⁻ aerosols were noticed to be substantially higher (more than double) within 24 h. In general, scavenging ratios for all components (except Ca²⁺, NH₄⁺ and K⁺) were higher over BOB as compared to Hyderabad. The maximum fall in aerosol levels (BR minus AR) was observed during continuous and low intensity rain events that did not allow building up of aerosol concentrations.     

南京市大气颗粒物春季污染的特征

采用大流量采样器,于2002年春季(3月)对南京市城区PM₁₀、PM_2.5(大气中粒径dp≤10或2.5mm的颗粒物)进行了研究测定,并对其水溶性组分及Ph值进行分析.结果表明,南京市大气颗粒物春季污染严重,PM₁₀超标率达83%.PM_2.5全部超标,超标倍数为1.8～4.9.PM_2.5的酸性明显强于PM₁₀. PM_2.5中水溶性组分占总量的24.4%,其中,阴离子约为8.0%,水溶性金属元素+NH₄⁺约为8.9%,TOC约为7.5%.这些水溶性组分对干、湿沉降的酸度影响较大,且主要以细颗粒的形态存在,其在大气中滞留时间较长,对人类的影响深远,应引起足够重视.     

伊犁河谷夏季PM2.5和PM10中水溶性无机离子浓度特征和形成机制

区域尺度大气颗粒物的同步观测与分析是制定大气污染防治策略的重要途径.为研究伊犁河谷城市群大气颗粒物和水溶性无机离子的空间分布特征,于2021年7月19~29日期间同步采集伊宁市和周边三县大气颗粒物样品,深入分析了PM_2.5和PM₁₀中9种水溶性无机离子（WSIIs）的空间分布特征、存在形式和影响因素,并对二次无机颗粒物的形成机制进行了探讨.结果表明,夏季伊犁河谷城市群ρ（PM_2.5）和ρ（PM₁₀）均值分别为（23±3）μg ·m^-3和（59±7）μg ·m^-3,伊宁市受本地工业源和移动源排放影响,导致其PM_2.5浓度在区域中最高;伊宁县受扬尘源和地形影响,使其PM₁₀浓度在区域中最高;而霍城县的良好扩散条件使其PM_2.5和PM₁₀浓度最低.PM_2.5和PM₁₀中WSIIs占比分别介于28.2%~29.9%和16.0%~20.2%之间.4种主要离子（SO₄^2-、NO₃^-、NH₄⁺和Ca²⁺）占到WSIIs的90%左右,在PM_2.5中浓度大小排序为：SO₄^2->Ca²⁺>NH₄⁺>NO₃^-,在PM₁₀中浓度大小排序为：SO₄^2->Ca²⁺>NO₃^->NH₄⁺;相关性研究结果显示4个城市SO₄^2-浓度相近主要是由区域输送所致,而Ca²⁺在PM_2.5和PM₁₀中占比高于国内大部分城市反映出伊犁河谷核心区城市受扬尘源的影响较大.PM_2.5和PM₁₀中n（NO₃^-）/n（SO₄^2-）分别为0.78和0.76,表明伊犁河谷受固定源影响大于移动源;4个城市n（NO₃^-）/n（SO₄^2-）的大小排序为：伊宁市>霍城县>伊宁县>察县,与各城市机动车保有量大小一致,反映出伊宁市受机动车等移动源的影响高于周边三县.二次组分主要以（NH₄）₂SO₄、NH₄HSO₄和NH₄NO₃的形式存在,各城市NH₄⁺与SO₄^2-反应后均有盈余,盈余的铵盐在伊宁市主要以NH₄NO₃存在,与伊宁市较高的NO₂浓度有关.夏季PM_2.5和PM₁₀中NOR变化幅度分别为0.03~0.10和0.03~0.16,受夏季高温影响导致NO₃^-二次转化较弱;SOR分别介于0.21~0.41和0.23~0.44之间,察县相对较高的湿度使其SOR较高,而霍城县受区域输送影响使其SOR高于伊宁市.形成机制表明：察县和伊宁市的SO₄^2-主要由非均相反应生成,伊宁县主要由均相反应产生,而霍城县SO₄^2-的形成机制较为复杂,受到均相反应和非均相反应的共同影响.     

2017年1月天津市区PM2.5化学组分特征及高时间分辨率来源解析研究

为了快速分析天津市区冬季以及重污染过程中PM_2.5的化学组成特征及来源,本研究于2017年1月利用在线监测仪器快速采集了天津市区环境受体中PM_2.5及其化学组分的小时数据,并通过PMF（positive matrix factorization,正定矩阵因子分解法）模型解析了天津市区2017年1月及重污染过程中PM_2.5的主要贡献源类,分析了重污染过程中排放源的变化趋势.结果表明：2017年1月天津市区PM_2.5浓度为6.0~449.0 μg·m^-3,平均值为153.3 μg·m^-3.NO₃^-、SO₄^2-、NH₄⁺是PM_2.5中水溶性离子的主要组分,三者之和占水溶性离子总量的88.3%.NH₄⁺与Cl^-、NO₃^-、SO₄^2-均表现出显著的正相关性（r=0.82,0.95,0.97;p<0.01）.NO₃^-和SO₄^2-（r=0.90;p<0.01）,Ca²⁺与Mg²⁺（r=0.65;p<0.01）均表现出显著的相关性,说明它们分别具有较高的同源性.OC和EC也是PM_2.5的重要组成部分,两者之和占PM_2.5质量浓度的20.4%.重污染过程中,PM_2.5及其主要离子的浓度显著的增加（p<0.01）,并存在较高的二次离子生成.PMF解析结果表明,二次源类是天津市区2017年1月PM_2.5的首要源类,分担率为38.1%,其次为机动车源（分担率为25.6%）、燃煤源（分担率17.1%）、扬尘（分担率10.1%）和生物质燃烧（分担率9.1%）.重污染过程中,二次源是PM_2.5的主要贡献源类,分担率达到39.3%;说明重污染期间存在显著的二次转化及二次粒子的积累过程.重污染发生演变过程中,二次源、机动车源和燃煤源对PM_2.5贡献表现出显著增加的趋势,而扬尘和生物质燃烧的贡献则没有显著增加.     

鼎湖山森林土壤种子库动态研究

在鼎湖山森林季风常绿阔叶林、针阔混交林、马尾松林林型中研究土壤种子库储量、多样性格局和生活型等。通过分析两层取土样，风干土壤样品，对样品进行筛选，过滤出种子，并进行种子分类鉴定，用土芯实验法检测土壤种子库的组成。结果表明，在4个取样地点的种子库中，上层种子的Shannon多样性指数和Simpson指数都明显高于下层。草本植物不仅是种类还是数量上都是这三种林型土壤种子库的主体成分，特别是在针叶林中，种子储量占有十分显著的优势地位，随着演替年龄的增长，草本植物在种子库储量中占的比例有所减少。另外，种子库中优势成分与取样地点地面植被相应层次的优势种存在较大差异，说明植物群落地上部分的发育与其它地下部分的土壤种子库的发育具有明显的不同步性，这一结果表明土壤种子库的内在潜力对森林更新及植物群落演替动态产生了重要影响。     

郑州市大气PM2.5的污染特征及源解析

为全面解析郑州市环境空气PM_2.5的化学特征及来源,按照城市功能分区的差异,在郑州市沿主导风向选择4个监测点位,采用大流量采样器分别在采暖季和非采暖季采集40个PM_2.5样品。监测数据表明,郑州市环境空气PM_2.5在采暖季和非采暖季的浓度范围均值高达197、173μg/m³,已属于严重污染;PM_2.5成分分析结果表明,Zn、Pb、Cu、Mn等是PM_2.5中的主要污染元素,其富集系数分别为110、94.9、10.9和5.0;主成分分析结果表明,建筑扬尘、土壤尘及道路扬尘、汽车尾气、煤炭燃烧是郑州市PM_2.5的主要来源,其累计贡献率超过90%。     

Amounts of non-fibrous components in recovered paper

Paper and board recycling is now a central issue in papermaking. Understanding of material flows, as a part of the total production chain, as well as, fibrous and non-fibrous component flows needs further clarification. These flows are studied at a European level, with special focus on Germany and Sweden. Non-fibrous components are discussed in terms of a material which hampers the processing of paper and board. Resource-efficiency improvements, in conjunction with economic benefits, are sought and recycling has been able to fulfil both of these. The main drivers to maximize the use of recovered paper in paper and board manufacturing, have been improved over the last decades. These drivers are cost, environmental image and good technical properties to be used as raw material.The increased recycling rate has reduced the quality of the collected paper, produced recycled paper, and replaced virgin pulp. Also, recycling as a process, like deinking, produces large amounts of waste material that has challenges to find proper utilization. These problem areas are addressed in this paper, too.One focus area in the analysis of statistical information is an estimation of the share of non-fibrous components and fibre volumes of paper in Europe (EU) for the year 2010.