Aging activity of DDE in dissimilar rice soils in a greenhouse experiment

A green-house study was conducted in late 2005 to investigate the aging behavior of p,p'-DDE in two types of soil, Hydragric Anthrosols (An) and Hydragric Acrisols (Ac), according to the World Reference Base (WRB) [FAO/ISRIC/ISSS. 1998. World reference base for soil resources. World soil resources reports, Rome. p. 87]. Paddy rice and dry rice were grown in submerged paddy soils and non-submerged upland soils, respectively. The concentration of extractable p,p'-DDE in fresh DDE-spiked soils was 746.2ngg(-1). During the first few weeks of the experiment, the extractability of p,p'-DDE became increasingly low as the aging period prolonged. However, certain amount of p,p'-DDE that had been captured by soil minerals and organic matter (OM) could be released and became extractable in the later period. The extractability of p,p'-DDE in submerged soils was significantly lower than that in non-submerged soil, because flooding could increase the binding of pollutants to soil particles. The plantation of both dry rice and paddy rice slowed down the aging process of p,p'-DDE. After one month's growth of rice, p,p'-DDE bound to soil particles was released and became extractable. The OM and silt content of An are higher than that of Ac, resulting in more bound residues and relative lower extractability of p,p'-DDE in An. In addition, the extractability of p,p'-DDE could be reduced by the addition of rice straw to soils.     

Characterizing effects of uncertainties in MSW composting process through a coupled fuzzy vertex and factorial-analysis approach

A coupled fuzzy vertex and factorial-analysis approach was developed in this study for systematically characterizing effects of uncertainties in a municipal solid waste composting process. A comprehensive composting process model was also embedded into the system framework and used to address substrate decomposition and biomass growth, as well as the interactions between moisture contents, temperatures, and oxygen concentrations. The applicability of the proposed method was verified through a custom-made pilot-scale composting system. Results from fuzzy simulation indicated that the fuzzy vertex method could effectively communicate implicit knowledge into dynamic simulations and thus provide valuable information for enhancing composting process control under uncertainty. The factorial analysis was effective in quantifying the proportion to which the uncertainty of each single or interactive effect of model parameters contributes to the overall uncertainty of the system outcomes. Thus, sensitive parameters that may lead to errors or unreasonable predictions can be determined. The proposed study system could not only be used in characterizing combined effects of uncertainties for composting processes, but was also applicable to many other environmental modelling systems.     

江苏省一次典型沙尘污染过程分析

2021年4月16日至4月18日江苏省经历了一次受沙尘影响的重污染过程.本次过程沙源地为蒙古国中南部及中国内蒙古中西部地区,在蒙古气旋后部西北大风影响下,沙尘气团自西北向东南影响了中国多个省市和地区.江苏省自16日起逐渐受到沙尘过程影响,苏北城市ρ(PM10)从凌晨开始迅速升高,浓度最高达569μg/m3,空气质量达严...     

Comparison of quartz sand, anthracite, shale and biological ceramsite for adsorptive removal of phosphorus from aqueous solution

The choice of substrates with high phosphorus adsorption capacity is vital for sustainable phosphorus removal from waste water in constructed wetlands. In this study, four substrates were used： quartz sand, anthracite, shale and biological ceramsite. These substrate samples were characterized by X- ray diffractometry and scanning electron microscopy studies for their mineral components （chemical components） and surface characteristics. The dynamic experimental results revealed the following ranking order for total phosphorus （TP） removal efficiency： anthracite 〉 biological ceramsite 〉 shale 〉 quartz sand. The adsorptive removal capacities for TP using anthracite, biological ceramsite, shale and quartz sand were 85.87, 81.44, 59.65, and 55.98 mg/kg, respectively. Phosphorus desorption was also studied to analyze the substrates＇ adsorption efficiency in wastewater treatment as well as the substrates＇ ability to be reused for treatment. It was noted that the removal performance for the different forms of phosphorus was dependent on the nature of the substrate and the adsorption mechanism. A comparative analysis showed that the removal of particulate phosphorus was much easier using shale. Whereas anthracite had the highest soluble reactive phosphorus （SRP） adsorptive capacity, biological ceramsite had the highest dissolved organic phosphorus （DOP） removal capacity. Phosphorus removal by shale and biological ceramsite was mainly through chemical adsorption, precipitation or biological adsorption. On the other hand, phosphorus removal through physical adsorption （electrostatic attraction or ion exchange） was dominant in anthracite and quartz sand.     

树脂基纳米零价铁复合材料的制备及其去除重金属铅Pb(Ⅱ)的性能研究

凭借着优越的还原活性,纳米零价铁在环境污染治理和修复领域应用广泛。通过将纳米零价铁(n ZVI)颗粒负载到大孔阴离子和阳离子交换树脂上,成功制备出2种树脂基纳米零价铁复合材料。研究了2种复合材料及其载体对水溶液中Pb(Ⅱ)的去除性能,考察了不同载体功能基团对复合材料去除Pb(Ⅱ)性能的影响。结果表明:以大孔阴离子交换树脂为载体的D001-Fe0复合材料因具有离子交换和化学还原双重作用,对Pb(Ⅱ)的去除效率高、速率快。     

Promoting effect of vanadium on catalytic activity of Pt/Ce–Zr–O diesel oxidation catalysts

A series of Pt–V/Ce–Zr–O diesel oxidation catalysts was prepared using the impregnation method. The catalytic activity and sulfur resistance of Pt–V/Ce–Zr–O were investigated in the presence of simulated diesel exhaust. The effect of vanadium on the structure and redox properties of the catalysts was also investigated using the Brunauer–Emmett–Teller method,X-ray diffraction, H2temperature-programmed reduction, CO temperature-programmed desorption, X-ray photoelectron spectroscopy, and Energy Dispersive Spectroscopy. Results showed that the Pt particles were well dispersed on the Ce–Zr–O carrier through the vanadium isolation effect, which significantly improved the oxidation activity toward CO and hydrocarbons. An electron-withdrawing phenomenon occurred from V to Pt, resulting in an increase in the metallic nature of platinum, which was beneficial to hydrocarbon molecular activation.     

污水集中处理厂污水中金属(重金属)的分布

系统地建立集中污水处理装置是环境管理和污染治理的发展方向之一，在工业发达国家已相当普及，本文分析了美国和加拿大污水集中处理厂原污水和常用治理流程各工序中金属（重金属）的分布情况。结果表明，由于地理，气候，人口，特别是工业分布的影响，原污水中金属含量会有较大变化，因为变化范围大且超过排放标准2－10倍（按均值计），在设计和评价时应予化重点考虑的几种金属为：Cd,Cu,Cr,Pb,Ni和Zn，经典型的沉淀－活性污泥工艺处理后，金属除去率大于80％，可以满足排放要求。     

CALPUFF模型在大气环境容量测算中的应用研究

本研究利用CALPUFF空气质量扩散模式模拟了凉山州2007年气象场和s02浓度场,通过现状监测结果与模拟结果的比较评述了模型的适用性;并根据西昌市现状污染源和虚拟污染源情况,通过CALPUFF模拟建立大气污染物传递矩阵,结合线性优化模型测算了西昌市大气环境容量。     

物种多样性对植物生长与土壤镉污染修复的影响

土壤重金属污染是当今最为突出的环境问题之一,其中,重金属镉(Cd)已成为我国受污染土壤中最主要的无机污染物之一.植物修复法是去除土壤重金属的重要方法,研究表明,植物物种多样性的增加能促进生态系统功能.那么在Cd污染土壤中,植物物种多样性对植物生长和Cd污染修复会有怎样的影响,其内在机理是怎样的并不清楚.基于此,本研究选择6种本地常见草本植物(荆芥、鸡眼草、短叶水蜈蚣、牛筋草、鸭跖草和细风轮菜),通过室内控制实验研究不同植物物种多样性(1-,2-,3-,6-物种)对植物生长与土壤Cd污染修复的影响.结果表明:植物物种多样性的增加显著促进植物地下生物量和总生物量的积累,并对植物根系形态(根总长、根总表面积、根尖总数与根平均直径)和叶绿素荧光参数(PSII最大光能转化效率F_v/F_m和PSII潜在活性F_v/F_0)有显著的促进作用;植物物种多样性的增加能显著提高植物地上、地下及总Cd含量(积累量)和富集系数;植物物种多样性的增加对植物生长、根系形态指标及Cd的富集具有显著的净效应,且以互补效应为主.本研究选取的是对环境条件要求不高、生长周期短的本地草本植物,可为利用本地常见短世代周期植物进行土壤重金属污染修复提供理论依据.     

废弃采石场作为一般工业固体废物填埋场址探析

从城市工业固体废物消纳和废弃采石场作为填埋处置场地的角度出发,对利用废弃采石场作为第Ⅰ类一般工业固体废物填埋场场址条件进行探讨,通过广州市地区实例说明利用废弃采石场选址作为第Ⅰ类一般工业固废填埋场址的可用性,这对未来废弃采石场的综合利用具有一定的借鉴意义。