基于污泥堆肥产物与余泥渣土制备的人工土壤的理化性质分析与评价

为实现污水厂污泥及余泥渣土的协同处理和资源化利用,以“两步法”制备人工土壤,考察不同配比条件对人工土壤理化性质的影响。结果表明：污水污泥与3种不同辅料 (玉米秸秆、菌菇渣、木屑) 配比后进行好氧堆肥,堆肥结束后腐熟度符合国家相关标准要求,将污泥堆肥产物和余泥渣土制备得到人工土壤,其理化性质与天然土壤类似。堆肥添加量能显著影响人工土壤水稳性团聚体、pH值、EC、有机质、总氮及有效磷含量,在人工土壤种植应用时,污泥+玉米秸秆的堆肥种植效果最好,采用改进的内罗梅综合指数法进行综合评价,综合考虑,污泥+玉米秸秆堆肥产物添加量为30%、余泥渣土添加量为70%和污泥+玉米秸秆堆肥产物添加量为50%、余泥渣土添加量为50%是最优质的人工土壤,污泥+木屑堆肥次之,污泥+菌菇渣堆肥效果最差。     

Organochlorine pesticides in soil profiles from Tianjin, China

Soil cores were collected from soils at five sites in Tianjin area for the determination of hexachlorocyclohexane isomers (HCHs, including alpha-HCH, beta-HCH, gamma-HCH and delta-HCH), dichlorodiphenyltrichloroethane and metabolites (DDXs, including p,p'-DDT, p,p'-DDE and p,p'-DDD) and total organic carbon (TOC). The levels and vertical distributions of HCHs and DDXs are studied. Results show that the application of pesticides in the past years was the major contributor of HCHs and DDXs accumulation in the sampling areas. Significant positive correlations were seen between the residual and application amounts of HCHs and DDXs. Wastewater irrigation did not bring a significant contribution of HCHs or DDXs into the soils. HCHs and DDXs concentrations peak at the surface and decline in soil profile with depth, while fluctuations were observed in the plow layers of some cultivated soils caused by frequent cultivation activities and batch irrigation. Positive correlations were observed between the contents of TOC and HCHs and DDTs. Although the amounts of HCHs application in all sampling sites are larger than DDXs, at surface and near surface layers of most sampling sites, the concentrations of summation operatorHCHs are lower than summation operatorDDXs. The composition of DDXs in the applied pesticides and sampled soils indicates that there is no recent DDT input at the sample areas.     

Quality assured measurements of animal building emissions: gas concentrations

Comprehensive field studies were initiated in 2002 to measure emissions of ammonia (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), methane (CH4), nonmethane hydrocarbons (NMHC), particulate matter <10 microm in diameter, and total suspended particulate from swine and poultry production buildings in the United States. This paper focuses on the quasicontinuous gas concentration measurement at multiple locations among paired barns in seven states. Documented principles, used in air pollution monitoring at industrial sources, were applied in developing quality assurance (QA) project plans for these studies. Air was sampled from multiple locations with each gas analyzed with one high quality commercial gas analyzer that was located in an environmentally controlled on-farm instrument shelter. A nominal 4 L/min gas sampling system was designed and constructed with Teflon wetted surfaces, bypass pumping, and sample line flow and pressure sensors. Three-way solenoids were used to automatically switch between multiple gas sampling lines with > or =10 min sampling intervals. Inside and outside gas sampling probes were between 10 and 115 m away from the analyzers. Analyzers used chemiluminescence, fluorescence, photoacoustic infrared, and photoionization detectors for NH3, H2S, CO2, CH4, and NMHC, respectively. Data were collected using personal computer-based data acquisition hardware and software. This paper discusses the methodology of gas concentration measurements and the unique challenges that livestock barns pose for achieving desired accuracy and precision, data representativeness, comparability and completeness, and instrument calibration and maintenance.     

气相分子仪测定水中的硫化物

用气相分子吸收光谱仪测定水中的硫化物，对其工作曲线、精密度等进行了试验，表明方法简便、快捷、精密度、准确度都较好，适用于各种水质硫化物的测定。     

常熟河网区水污染物总量控制研究

基于常熟河网原型调水实验和水功能区划，建立了感潮地区河网水量水质模型，对常熟河道水质降解系数及水环境容量进行了计算，并按照点源和面源对区域内污染源进行统计，在此基础上进行了常熟河网水污染物总量控制值和现状削减量的计算，为该地区的水污染防控提供了科学依据。     

超声去除垃圾渗滤液中的氨氮

采用超声辐照技术去除垃圾渗滤液中的氨氮.研究结果表明,超声辐照对垃圾渗滤液中的氨氮有很好的去除效果.渗滤液中氨氮超声去除的机理主要是氨氮以游离氨的形式在空化泡内发生高温热解反应,生成氮气和氢气而排出.     

新型沸石填料间歇硝化反应器的研究

介绍一种新型沸石填料 ,用于提高生物脱氮系统中硝化反应器的硝化性能。试验结果表明 ,应用了沸石填料的硝化反应器的硝化性能得到了显著提高 ,在脱氮效率和速率上 ,与普通生物载体硝化反应器相比具有明显的优势。硝化反应器连续运行 17d ,出水氨氮基本在 1mg/L以下 ,氨氮去除率在 97%以上。该系统停止运行 5 0d后再次启动 ,一周内硝化性能得以恢复     

Changes of copper speciation in maize rhizosphere soil

Chemical forms of copper in the rhizosphere and bulk soil of maize were investigated using rhizobox cultivation and sequential extraction techniques. The copper accumulations were also determined. The results demonstrated that there were continuous changes in copper fractionation within the maize rhizosphere. Initially, the amount of exchangeable copper increased before dropping below the initial level after 40 days or so. Carbonate associated copper followed a similar trend of change, but with a slower pace than the exchangeable copper. The increase in carbonate associated copper only become evident after 30 days, with the net loss occurring after 60 days. There were also initial increases in oxide bound copper as well as decreases in the organic matter associated copper, both followed by a turnover after 40-50 days. The accumulation of copper in the maize plant was found to be biomass dependent. The amount of accumulated copper absorbed in the plant material exceeded the initial quantity of the exchangeable copper in the soil, revealing a transformation from less bioavailable to more bioavailable fractions. During cultivation, decreases in redox potential and increases in pH, dissolved organic carbon (DOC), and microbial activity in the maize rhizosphere were observed. The change in copper speciation may result from root-induced changes in DOC, redox potential, and microbial activity in the rhizosphere.     

Ce掺杂纳米TiO2光催化剂的制备及降解甲醛的研究

介绍了溶胶-凝胶法制备Ce离子掺杂纳米TiO2的工艺流程.采用X射线衍射(XRD)、紫外可见分光光度法(UV-Vis)等方法表征了Ce掺杂TiO2的相组成、紫外可见漫反射率与掺杂量的关系.结果表明,掺杂的TiO2在520℃、650℃焙烧2 h呈锐钛矿结构,在520℃焙烧2 h的TiO2的晶粒尺寸大约为20 nm,而掺杂Ce后其晶粒尺寸均减小,大约为12nm.UV-Vis吸光度分析表明,掺Ce后吸收带边明显发生红移,但随着Ce掺杂浓度的增大,其对可见光的吸收影响不大.光催化降解反应表明,未掺杂Ce的TiO2反应2 h后对甲醛的没有降解作用,而Ce掺杂TiO2反应2 h后甲醛降解率达15%.     

The associations of air pollution exposure during pregnancy with fetal growth and anthropometric measurements at birth: a systematic review and meta-analysis

Environmental Science and Pollution Research - Fetal growth has been demonstrated to be an important predictor of perinatal and postnatal health. Although the effects of maternal exposure to air...