Biodegradability of soil water soluble organic carbon extracted from seven di erent soils

Water soluble organic carbon (WSOC) is considered the most mobile and reactive soil carbon source and its characterization is an important issue for soil ecology study. A biodegradability test was set up to study WSOC extracted from 7 soils di erently managed. WSOC was extracted from soil with water (soil/water ratio of 1:2, W/V) for 30 min, and then tested for biodegradability by a liquid state respirometric test. Result obtained confirmed the finding that WSOC biodegradability depended on the both land use and management practice. These results suggested the biodegradability test as suitable method to characterize WSOC, and provided useful information to soil fertility.     

Characterization of organic matter in total suspended particles by thermodesorption and pyrolysis-gas chromatography-mass spectrometry

The organic matter in tropospheric aerosol plays an important role in atmospheric physical and chemical processes. The bulk of organic matter, representing a significant proportion of the total suspended particulate (TSP) mass, is bound to polymeric material whose structure and properties are largely unknown. Here we used thermodesorption gas chromatography/mass spectrometry (Td- GC/MS) to study organic compounds of low molecular mass and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) to characterize the chemical structure of macromolecules in TSP samples collected in di erent seasons from di erent sites in Guangzhou. n-Alkanes, fatty acids and nitriles were the predominant compounds in the thermodesorption products, whereas aromatics, fatty acids, nitriles and n-alkanes/alkenes were the major compounds in the pyrolysates. The results indicated that aromatics were main units in macromolecules. The fatty acids and nitriles formed from carboxylic ammonium salts were detected in both thermodesorption products and pyrolysates at a certain concentration, indicating the importance of these compounds in TSP formation. The TSP source mainly determined the occurrence of compounds in samples from urban, suburban and forest sites, whereas the TSP source and formation process maybe controlled the seasonal variation in compounds detected. High levels of nitriles in summer samples from suburban and forest sites coincide with the release of ammonium from the land and of fatty acids from vegetation at these sites.     

水解(酸化)工艺预处理难降解有机废水应用技术分析

本文对水解(酸化)工艺进行了原理分析,论述了该工艺的优缺点,以及对后续工艺的影响.分析论述了该工艺对几种典型的难降解有机废水的降解机理.认为水解(酸化)作为难降解有机废水的预处理工艺具有很高的推广应用价值.     

低分子量有机酸对岩源磷释放的实验研究

低分子量有机酸是微生物和植物根系分泌物中重要的组成部分.采用浸泡实验比较了4种常见低分子量有机酸(草酸、酒石酸、柠檬酸、苹果酸)对巢湖北岸东部富磷地层中岩源磷的释放量,并对浸提后的部分残渣进行磷的赋存形态分析.结果表明,当有机酸浓度小于5mmol·L-1时,柠檬酸的释磷量最大;大于5mmol·L-1时,草酸和酒石酸的释磷量最大,此时释磷量与有机酸的浓度具有一定的线性关系,其增加趋势远大于浓度小于5mmol·L-1时的增加趋势,而其中草酸和酒石酸又远大于柠檬酸和苹果酸.在有机酸溶液终止pH≥4时,有机酸溶液终止pH与释磷量有较好的线性关系.在50mmol·L-1相同浓度时,草酸对各赋存形态磷转化作用均最大,酒石酸次之.而4种酸对有机磷释放率最大,均高达97%以上,对闭蓄态磷的释放率最小.     

组合人工湿地对城镇污水处理厂尾水中有机物的去除特征研究

采用物理分级和三维荧光光谱法,研究了组合人工湿地对城镇污水处理厂尾水中不同形态有机物的去除特征.结果表明,组合人工湿地对污水处理厂尾水具有较好的深度处理效果,出水水质基本可以达到国家地表水环境质量标准(GB38382-2002)Ⅲ或Ⅳ类水标准.组合人工湿地处理系统对尾水中CODCr和BOD5总体去除率分别达到35.2%和44.3%,对尾水中总有机碳(TOC)、溶解性有机碳(DOC)、颗粒有机碳(POC)的平均去除率分别为46.9%、45.9%、48.3%.组合人工湿地系统不同单元对尾水中有机物的去除贡献率存在差异,其中,潜流湿地单元对尾水中CODCr和BOD5及其不同组分有机碳的去除效率较高.试验期间,由于藻类滋生,表流湿地单元出水中有机物含量波动较大,去除效果明显降低,藻类被打捞后,出水水质明显改善.三维荧光光谱分析结果显示,各个处理单元取样点的水样三维荧光光谱均出现4个明显的荧光峰.人工湿地各单元出水溶解性有机质(DOM)中,类蛋白和类腐殖酸物质含量较高,类富里酸物质含量较低.人工湿地对类蛋白和类腐殖酸物质有较强的去除作用.     

序批式颗粒污泥系统中磷的变化和去向分析

在实验室序批式活性污泥法(SBR)处理系统中以普通活性污泥为接种污泥,采用厌氧-好氧的运行方式提高系统的除磷效果.同时培养颗粒污泥,并对系统中磷的变化和去向进行分析.结果表明,整个试验共运行146 d,成熟颗粒污泥平均粒径为603μm,污泥体积指数(SVI)约为30 mL.g-1,COD去除率可达90%,磷的去除率可达95%左右.颗粒污泥系统除厌氧放磷和好氧聚磷以外,还存在明显的污泥颗粒积磷现象.磷的去除途径主要为:系统排泥(出水悬浮物和专门排泥)和污泥积磷.由厌氧末期颗粒污泥的X射线衍射(XRD)分析结果可知,化学沉淀是污泥积磷的一种重要方式,大量的金属离子会与磷形成无机盐沉积在污泥颗粒上.     

基于稳定同位素示踪的流域颗粒有机物质来源辨析

为有效控制流域水质污染,保证饮用水水源的水质安全,通过采集和测定流域内土壤、植物以及河流断面水体悬浮颗粒有机质(POM)在枯水期和丰水期的碳、氮稳定同位素值和C/N比值,对石头口门水库汇水流域水体POM的来源进行研究.结果表明,水体中POM主要来源于土壤有机质,其贡献为69.2%,藻类等大型水生生物和浮游植物的贡献分别为23.1%和7.7%.流域水体中POM的来源存在时空差异.丰水期,浮游植物和藻类等大型水生植物的贡献均为15.4%,而枯水期后者的贡献提高到了30.8%.水体POM主要来源于双阳河和饮马河下游的土壤有机质,说明该区域土壤侵蚀较重,易发生非点源污染;岔路河和饮马河上游支流小黄河,水体POM以浮游植物的贡献占主导,其贡献分别为86.3%和94.8%,这些区域侵蚀较弱,非点源污染发生的风险小;大中型水库区域的POM主要由藻类等大型水生植物贡献,表明悬浮颗粒物在进入水库后可能发生了明显沉积.     

中国表层土壤有机质空间分布模拟分析方法研究

气候变化背景下,对土壤有机碳的研究是目前大尺度上土壤性质研究的热点。基于第二次全国土壤普查5 374个典型土壤剖面数据,分析表层土壤有机质(20 cm)与环境因素的相关关系,利用多元回归模型和HASM模型结合的方法模拟中国国家尺度上表层土壤有机质含量的空间分布格局,探讨该方法的模拟误差,为国家尺度上有机碳的估算提供方法参考。研究结果表明,对350个检验点模拟结果的平均绝对误差和平均相对误差为15.61 g.kg-1和56.59%,与普通克里格法相比分别降低了1.61 g.kg-1和20.84%;对样点分布较少以及无样点的西北地区和台湾省的模拟结果也更符合实际情况。建模样点减少一半的情况下,模拟结果的平均绝对误差和平均相对误差仅分别增加了0.14 g.kg-1和1.07%。因此,论文方法可作为模拟国家尺度上有机质空间分布相对有效的方法,同时如何使模型解释更多的土壤有机质空间变异将是进一步提高模拟精度的关键。     

Gallic acid和SDS对黑麦草体内重金属亚细胞及形态分布的影响

通过盆栽试验,研究了投加螯合剂没食子酸gallic acid(5mmol·kg-1)与表面活性剂十二烷基磺酸钠SDS(1mmol·kg-1)对黑麦草(Lolium perenneL.)体内重金属亚细胞及形态分布的影响.结果表明,单独投加gallicacid增强了黑麦草对Cd、Pb的区室化作用及对Zn的细胞壁沉积作用;复合投加gallic acid和SDS增强了黑麦草对Cd的区室化作用和细胞壁沉积作用,以及对Zn的细胞壁沉积作用.单独投加gallic acid使黑麦草体内Cd、Zn总量分别增加了33.5%和6.0%,其中,惰性态Cd、Zn所占比例分别增加了6.2%、6.3%;复合投加gallic acid和SDS使黑麦草体内Cd总量增加了35.6%,Zn总量减少了1.1%,其中,惰性态Cd、Zn所占比例分别增加了7.2%、8.6%,增强了植物对Cd、Zn的螯合作用.各处理对Pb的亚细胞分布及形态无明显影响.     

Organic matter extracted from activated sludge with ammonium hydroxide and its characterization

In order to characterize the organic properties of waste activated sludge in a wastewater treatment plant,organic matter within sludge was extracted with NH 3 ·H 2 O preferentially,and subsequently fractionated into five fractions using XAD-8/XAD-4 resins.Up to a 63.8%-71.1% of organic matter within the sludge could be efficiently extracted by NH 3 ·H 2 O.Fractionation results showed that hydrophobic acid and hydrophilic fraction were two main components among the sludge organic matter (accounting for 32.2% and 48.0% of the bulk organic matter,respectively),whereas transphilic acid,hydrophobic neutral and transphilic neutral were quite low (accounting for 9.2%,5.8% and 4.8%,respectively).Despite that the extractant of NH 3 ·H 2 O showed a relatively higher extraction efficiency of the aromatic components,the relatively low aromaticity of the organic fractions implied that those non-aromatic components could also be effectively extracted,especially for neutral and hydrophilic fractions.In addition,acidic fractions contained more aromatic humic-like components,whereas the neutral fractions had a greater content of aromatic proteins and soluble microbial byproduct-like components.Extraction of sludge organics with NH 3 ·H 2 O and subsequential fractionation using XAD resins could be a novel method for further characterization of sludge organics.