人工湿地基质中腐殖质的积累与分布特点

腐殖质来源于生物残体的降解,可参与多种污染物迁移转化,具有重要环境生态效应.本研究以常见的水平潜流和垂直流2种系统为研究对象,探讨了以无机基质为主构建的常规人工湿地中腐殖质的积累与分布特点.研究结果表明,随着污水处理运行,水平潜流和垂直流人工湿地中,大部分基质中腐殖质全碳量均有增加,水平潜流系统含量在1.7～ 18 g/kg,垂直流系统在1.9 ～7.5 g/kg;胡敏素是各系统腐殖质的主体组成,含量最高,水平潜流系统含量在1.55～17.22g/kg,垂直流系统在1.43 ～7.21 g/kg.腐殖质另外2种组分,富里酸和胡敏酸碳含量都比较低,水平潜流系统富里酸碳含量在0 ～0.68 g/kg,胡敏酸碳含量0.008 ～0.26g/kg;垂直流系统富里酸碳含量在0.015 ～0.38 g/kg,胡敏酸碳含量在0.05～0.15 g/kg,各系统中富里酸碳含量均高于胡敏酸碳含量;各系统中,根系基质腐殖质全碳及3种组分含量都显著高于非根际基质;不管是水平潜流还是垂直流,低水力负荷系统的比高水力负荷系统更高.     

高温堆肥与蚯蚓堆肥对城市污泥重金属形态的影响

采用高温堆肥和蚯蚓堆肥工艺，研究了城市污泥与锯末、粉煤灰或磷矿粉按不同比例混合堆肥前后重金属（Cu、Pb、Zn、Cd和As）交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态和残留态的变化。研究表明：高温堆肥和蚯蚓堆肥前后各试验污泥的重金属形态和含量呈现出不同的变化，都可以降低污泥中交换态Cu、Pb、Zn、Cd和As的含量；对于Cu和Pb，高温堆肥优于蚯蚓堆肥；对于Zn、Cd和As，蚯蚓堆肥优于高温堆肥。2种堆肥方式中，粉煤灰用量为10%的钝化效果优于20%，磷矿粉的钝化效果同粉煤灰一样。     

微生物生理群在猪粪秸秆高温堆肥碳氮转化中的作用

在自制的强制通风静态堆肥反应箱中,猪粪与秸秆以鲜重7∶1的比例进行了堆肥化实验,在堆制的23 d里根据堆温变化分阶段采集堆肥样品,利用MPN法测定了堆料中纤维素分解菌和氮素微生物生理群的数量变化,同时测定了相应的碳、氮含量。结果表明,纤维素分解菌在稳定腐熟阶段较多,对于后期有机碳的降解和腐殖质含量的增大起了很大的作用,在堆制的23 d里,腐殖质增加了2.4%。整个堆制过程中,氨化细菌的数量最大且与氨气释放浓度和铵态氮含量呈显著正相关,都在高温期增加,降温期后减少,氨化细菌的数量在高温期的增加率远高于降温期后的减少率,而铵态氮在高温期的增加率远低于在降温后期的减少率,铵态氮总体上减少了74.1%;亚硝化细菌数量与硝态氮呈正相关;反硝化细菌数量在降温期上升幅度较大,堆制结束时为堆制初期的13倍,且与堆肥中硝态氮含量呈正相关;硝态氮含量增加了87.5%;堆肥后期硝态氮的增加可能与堆肥中存在能进行硝化作用的反硝化细菌有关。固氮菌数量在堆制结束时达堆制初期的2.61倍,主要在降温期增加较多,对堆肥中有机氮的形成起很大作用。     

化学沥浸与硫化钠钝化联合处理猪粪中重金属

利用柠檬酸浸提猪粪中重金属,减少总量,再利用硫化钠钝化经柠檬酸浸提后的猪粪残渣,降低猪粪中剩余重金属的生物可利用性。柠檬酸浸提实验表明:0.2 mol·L-1柠檬酸与猪粪按固液比1:5混合,反应24 h,对猪粪中Cu、Zn、Mn的浸出率为18.10%、66.16%、43.85%;硫化钠投加量5%,钝化7 d,猪粪中离子交换态Cu、Zn、Mn的浓度由酸浸后的14.08、116、81.75 mg·kg~(-1)降为8.77、12.04、21.02 mg·kg~(-1),硫化钠对酸浸后猪粪中Cu、Zn的钝化率为52.00%、63.72%,猪粪残渣中离子交换态Mn所占全量的比例由对照组的30.22%降到7.77%;柠檬酸酸浸和硫化钠钝化对猪粪中Cu、Zn、Mn总处理效率为73.00%、61.44%、29.90%。重金属分离技术和钝化技术联合处理猪粪中重金属,可以有效减少猪粪中Cu、Zn、Mn的总量并降低其生物可利用性。     

污水处理中腐殖质的来源及其演变过程

污水中往往含有较多腐殖质和其前体物质,主要是动、植物残体以及它们被微生物分解后的有机质。腐殖质由胡敏酸(俗称腐殖酸)、富里酸和胡敏素组成,其分子结构主要以芳香环作为骨架,同时存在一定数量的多环环烷烃、含氮杂环,且在芳香环上还含有大量多种含氧官能团,包括羧基、酚羟基等。在污水处理过程中,沉砂池与初沉池可去除少量腐殖质;二级生物处理过程中微生物很难降解腐殖质,它们主要被活性污泥吸附而转移至污泥中;厌氧消化过程中,外源腐殖质沿程可能发生结构和形态变化,腐殖化程度会有所提高,同时还可能会有其前体物或细胞形成少量内源腐殖质生成。腐殖质结构中羧基、酚羟基等官能团会抑制厌氧水解过程,导致甲烷产率降低;原位金属离子可钝化腐殖质活性官能团,屏蔽其抑制水解作用。为此,需要研究污泥腐殖质在厌氧消化过程的演变规律,探知腐殖质化学与光谱特征,特别是羧基与酚羟基含量变化特征。     

有机与常规养殖生猪粪便重金属污染特征与农用风险评价

通过对中国有机与常规养殖场生猪粪便(以下简称猪粪)和饲料中的重金属Cr、As、Cd、Pb、Cu和Zn含量进行检测,对比分析了两种养殖模式下猪粪的重金属污染特征,估算猪粪安全农用年限。结果表明,有机和常规养殖场猪粪中Cr、As、Cd和Pb含量均未超标;常规养殖猪粪存在严重的Cu和Zn超标现象,样本超标率分别为100%和83%,而有机养殖猪粪中Cu和Zn样本超标率分别为22%和11%。除Cr外,常规饲料中重金属含量均高于有机饲料,Cu和Zn含量超标严重,且与猪粪Cu和Zn含量呈显著正相关关系(p0.05)。若依据施氮量400kg/(hm~2·a),则在连续施用常规养殖猪粪6～33、5～76a后,农田土壤Cu、Zn含量将分别超过《土壤环境质量标准》(GB 15618—1995)限值;而施用有机养殖猪粪的土壤则分别在24～163、18～136a后超过限值。     

污泥堆肥施用于草坪草栽培:Zn和Cu的分布特征简

为了探索污泥堆肥中重金属在土壤-植物系统中的积累与转移特性，通过温室盆栽实验，分析了污泥堆肥对草坪草高羊茅、黑麦草和白三叶生物量积累的情况，研究了污泥堆肥中Zn和Cu在植物和土壤中的分布特征。结果表明，污泥堆肥施用可以有效促进3种草坪草的积累生物量，在0~6 kg/m²的污泥堆肥施用量范围内，草坪草的生物量积累随着施用量的增加而提高。土壤中Zn和Cu的含量随污泥堆肥施加量的增加而增大，85%以上的Zn和Cu残留在土壤中。污泥堆肥中的Zn和Cu均可以被植物吸收，随着污泥堆肥施用量的增加，草坪草对Zn和Cu的吸收量增大，但当污泥堆肥施用量超过一定阈值时，草坪草吸收Zn和Cu不再增加，甚至减少；对于不同的草坪草，这一阈值有所不同。植物对Zn和Cu的吸收量只占土壤中Zn和Cu减少量的5%左右。根据生物富集系数（BCF）的计算结果推测，污泥堆肥的施用对土壤环境的影响大于对植物体内累积Zn和Cu的影响。     

腐殖质纳米颗粒对镉污染土壤的修复

外源腐殖质可改变土壤镉(Cd)的含量和状态。以风化煤为原料制备的不溶性胡敏酸为吸附剂,对比研究了其对冶炼厂周边污染土壤及人工模拟污染土壤中Cd的钝化效果。再以泥炭为原料,制备富里酸钾为主的水溶性腐殖酸钾为淋洗剂,用于活化、去除上述2种土壤中的Cd。结果表明,胡敏酸在砂质的人工模拟污染土壤中钝化效果更好,2%的剂量可使土壤中Ca Cl2提取态Cd的浓度(0.103 mg·L~(-1))降低19.7%。腐殖酸钾去除土壤Cd的效率随淋洗剂浓度增加而提高,在10 g·L~(-1)的浓度时,单次淋洗可去除高达38.1%的Cd。傅里叶变换红外光谱分析表明,腐殖质与Cd反应后形成了羧酸盐。因此,腐殖质纳米颗粒既可以钝化土壤中的Cd,也可以活化土壤中的Cd,从而达到修复Cd污染土壤的目的。其关键在于根据钝化或活化的目标,选择溶解度适当的腐殖质材料。     

鸡粪堆肥水溶性有机物转化特性研究

采用离子色谱和三维荧光光谱,分别对鸡粪堆肥不同阶段水溶性有机物(DOM)中典型小分子有机酸、磷酸和荧光有机物进行了研究。分析显示,所研究的7种酸(乙酸、琥珀酸、苹果酸、草酸、柠檬酸、酒石酸及磷酸)中,苹果酸的含量最高(1 000 mg/L),草酸的浓度最低(3 mg/L),琥珀酸和柠檬酸未检测到。随着堆肥的进行,各种酸的含量先上升而后下降,堆肥结束降至最低;堆肥过程样品所有荧光峰强度之和与COD达到显著相关(R=0.917,P0.05),类蛋白荧光峰强度与总荧光峰强度的比值不断降低,而类富里酸荧光峰强度与总荧光峰强度的比值不断上升。结果表明,堆肥过程小分子有机酸主要出现在堆肥中期;类蛋白荧光强度或类富里酸荧光强度与总荧光强度之比可以有效表征堆肥腐熟过程。     

多元统计分析研究不同物料堆肥富里酸紫外吸收光谱特性

应用紫外见光吸收光谱研究不同堆肥物料中富里酸(FA)的结构及腐殖化程度。采集9种不同物料的堆肥样本,分析FA紫外光谱特性,提取紫外特征参数并结合多元统计分析方法进行研究。结果表明:紫外特征参数之间相关性显著(E_2/E_4、E_(250)/E_(365)和E_(300)/E_(400)除外);选取相关性强的6个特征指标进行聚类分析和投影寻踪分析。2个结果基本一致,可根据腐殖化程度将9种不同来源堆肥样本由高到低分为4类:杂草,鸦粪、枯枝和猪粪,果蔬、秸秆和生活,沼渣和厨余。     

Co-composting of distillery wastes with animal manures: carbon and nitrogen transformations in the evaluation of compost stability

The aim of this work was to study the viability of recycling the solid wastes generated by the winery and distillery industry by means of co-composting with animal manures, as well as to evaluate the quality of the composts obtained. Two piles, using exhausted grape marc and cattle manure or poultry manure, respectively (at ratios, on a fresh weight basis, of 70:30), were composted by the Rutgers static pile composting system. Throughout the composting process, a number of parameters were monitored, such as pH, electrical conductivity, organic matter, water-soluble carbon, water-soluble polyphenols, different forms of nitrogen (organic nitrogen, ammonium and nitrate) and humification indices (humification ratio, humification index, percentage of humic acid-like C, polymerisation ratio and cation exchange capacity), as well as the germination index. Organic matter losses followed first-order kinetics equation in both piles, the highest organic matter mineralisation rate being observed with exhausted grape marc and cow manure. On the other hand, the mixture with the lowest C/N ratio, using exhausted grape marc and poultry manure, showed the highest initial ammonium contents, probably due to the higher and more labile N content of poultry manure. The increase in the cation exchange capacity revealed the organic matter humification during composting. In contrast, other humification parameters, such as the humification ratio and the humification index, did not show the expected evolution and, thus, could not be used to assess compost maturity. Composting produced a degradation of the phytotoxic compounds, such as polyphenols, to give composts without a phytotoxic character. Therefore, composting can be considered as an efficient treatment to recycle this type of wastes, due to composts presented a stable and humified organic matter and without phytotoxic effects, which makes them suitable for their agronomic use.     

Concentrations of monosaccharides in humic substances in the early stages of humification.

Deteriorated liquid packaging board (LPB) and biowaste compost are matrices, mainly consisting of cellulose, in the early stages of humification. Degradative studies on these matrices allow an examination of the role of carbohydrates in the synthesis of humic substances. Samples of different age were collected and divided by extraction into hot water extract (HWE), bitumen, humic acid (HA), fulvic acid (FA) and humin or residual fibre fractions. The following monosaccharides were identified in these fractions: L-arabinose, D-ribose, D-xylose, L-fucose, D-mannose, D-fructose, D-galactose, D-glucose, L-rhamnose and xylitol. The main component in all fractions was glucose. The concentrations of monosaccharides in humic acids (HAs) of LPB ranged from 67 to 503 mg/g of organic matter, and the concentrations in HAs of compost from 52 to 101 mg/g. As a general trend, the concentrations of monosaccharides decreased during LPB degradation and composting in all fractions. At the same time the relative amounts of D-xylose, D-mannose and D-galactose increased in HAs of compost samples.     

Co-composting of spent coffee ground with olive mill wastewater sludge and poultry manure and effect of Trametes versicolor inoculation on the compost maturity

The co-composting of spent coffee grounds, olive mill wastewater sludge and poultry manure was investigated on a semi-industrial scale. In order to reduce the toxicity of the phenolic fraction and to improve the degree of composting humification, composts were inoculated with the white-rot fungus Trametes versicolor in the early stages of the maturation phase.During composting, a range of physico-chemical parameters (temperature and both organic matter and C/N reduction), total organic carbon, total nitrogen, elemental composition, lignin degradation and spectroscopic characteristics of the humic acids (HAs) were determined; impacts of the composting process on germination index of Hordeum vulgare and Lactuca sativa were assessed. The coffee waste proved to be a highly compostable feedstock, resulting in mature final compost with a germination index of 120% in less than 5 months composting. In addition, inoculation with T. versicolor led to a greater degree of aromatization of HA than in the control pile. Moreover, in the inoculated mixture, lignin degradation was three times greater and HA increased by 30% (P < 0.05), compared to the control pile. In the T. versicolor inoculated mixture, the averages of C and N were significantly enhanced in the HA molecules (P < 0.05), by 26% and 22%, respectively. This improvement in the degree of humification was confirmed by the ratio of optical densities of HA solutions at 465 and 665 nm which was lower for HA from the treated mixture (4.5) than that from the control pile (5.4).     

The effect of pH, ion strength and reactant content on the complexation of Cu2+ by various natural organic ligands from water and soil in Hong Kong

The complexation constants for copper associated with different natural organic ligands, including dissolved organic carbon (DOC) extracted from water, water soluble organic carbon (WSOC), fulvic acid (FA) and humic acid (HA) from soil, were determined and then compared based on discrete single site model. Both ion-selective electrode (ISE) and anodic stripping voltammetry were used to determine the content of free copper ions, while the relative number of complexation sites was estimated using a fluorescence quenching (FQ) at the same time. ISE proved to be the most applicable technique when the concentration of copper was above 10(-7) moll(-1). The logk values for two WSOC sample sites (Song Ziyuan and Xin Niangtan) were 4.64 and 4.66; higher than both the DOC and HA values yet lower than the FA values, which were unusually high due to unavoidable pollution from the cation exchange resin used during the purification process. Binding affinities between the copper ions and the organic ligands obtained from streams in Yong Wei (DOC) and Song Ziyuan (WSOC) were influenced by pH, ion strength, and reactant concentration. Values for logk increased with increases in pH (ion strength of 0.1 N). At pH 4, the logk values decreased with increases in the supporting electrolyte concentration and total copper ion additions.     

Effects of humic substances on photodegradation of bensulfuron-methyl on dry soil surfaces

The photodegradation of the herbicide bensulfuron-methyl on dry soil surfaces in the presence and absence of humic substances was investigated under Xe lamp irradiation. A rapid rate of disappearance occurs in the humus-removed soil. The presence of humic acid (HA) and fulvic acid (FA) reduces degradation rates and has a quenching effect on the photodecomposition of bensulfuron-methyl. The quenching effect increases with increasing HA and FA concentration in soil. HA has a slightly greater ability to quenching the photolysis compared to FA. In addition, co-effects of HA and FA on quenching the photolysis are stronger than single effects of HA or FA.     

Effect of composting on characterization and leaching of copper, manganese, and zinc from swine manure.

This research was conducted to study the influence of composting on the concentrations, water solubility, and phase association of Cu, Mn, and Zn from swine (Sus domesticus) feces. Composting of separated swine manure was performed in two piles for 122 days. The metal concentrations increased rapidly during the first 49 days and leveled off thereafter. All metal concentrations increased approximately 2.7-fold in the final compost due to decomposition of organic matter. A sequential extraction protocol was used to evaluate the humification process and partition metals into water-soluble, exchangeable, organically complexed, organically bound, solid particulate, and residual fractions. Temporal changes in the water-soluble fractions of Cu, Mn, and Zn were reflected by water-soluble organic C concentrations, which rapidly increased to a maximum at Day 18 and declined thereafter. An increase in the humic acid/fulvic acid ratio in Na4P2O7 or NaOH extracts at various stages of composting represented the humification process. During composting, the major portions of Cu, Mn, and Zn were in the organically-bound, solid particulate, and organically complexed fractions, respectively. Metal distributions in different chemical fractions were generally independent of composting age and, thus, independent of respective total metal concentrations in the composts.     

INFLUENCE OF SOIL ORGANIC MATTER ON THE LEACHING OF POLYCYCLIC AROMATIC HYDROCARBONS IN SOIL

Polycyclic aromatic hydrocarbons (PAHs) are one of the main classes of contaminants in the terrestrial environment. Aside from total organic carbon, the ratio among the different organic matter fractions [dissolved organic matter, fulvic acid (FA), humic acid (HA) and humin] can also affect the mobility of these hydrocarbons in soils. In this study the effect of the whole organic carbon pool has been compared with that of HA and FA on the translocation of four PAHs (biphenyl, fluorene, phenanthrene and pyrene) in soil columns. Oxidized and untreated soil columns with and without HA or FA, were prepared, spilled with hydrocarbons and leached with a 0.01 M CaCl₂ solution. The influence of HA and FA on PAH translocation was investigated through determinations of the PAH contents and total organic carbon (TOC) in the layers of the columns. All molecules were moved vertically by the percolating solutions, their concentrations decreasing with depths. The non-oxidized soil tended to retain more PAHs (96%) than the oxidized one (60%), confirming that organic matter plays an important role in controlling PAH leaching. The whole organic matter pool reduced the translocation of pollutants downward the profile. The addition of HA enhanced this behaviour, by increasing the PAH retention in the top layers (7.55 mg and 4.00 mg in the top two layers, respectively) while FA increased their mobility (only 2.30 and 2.90 mg of PAHs were found in the top layers) and favoured leaching. In fact, in the presence of HA alone, the higher amounts of PAHs retained at the surface and the good correlation (r²=0.936) between TOC and hydrocarbon distribution can be attributed to a parallel distribution of PAHs and HA, while in the presence of FA, the higher mobility of PAHs can be attributed to the high mobility of the humic material, as expected by its extensive hydrophilic characteristics.     

Influence of soil organic matter on the leaching of polycyclic aromatic hydrocarbons in soil

Polycyclic aromatic hydrocarbons (PAHs) are one of the main classes of contaminants in the terrestrial environment. Aside from total organic carbon, the ratio among the different organic matter fractions [dissolved organic matter, fulvic acid (FA), humic acid (HA) and humin] can also affect the mobility of these hydrocarbons in soils. In this study the effect of the whole organic carbon pool has been compared with that of HA and FA on the translocation of four PAHs (biphenyl, fluorene, phenanthrene and pyrene) in soil columns. Oxidized and untreated soil columns with and without HA or FA, were prepared, spilled with hydrocarbons and leached with a 0.01 M CaCl2 solution. The influence of HA and FA on PAH translocation was investigated through determinations of the PAH contents and total organic carbon (TOC) in the layers of the columns. All molecules were moved vertically by the percolating solutions, their concentrations decreasing with depths. The nonoxidized soil tended to retain more PAHs (96%) than the oxidized one (60%), confirming that organic matter plays an important role in controlling PAH leaching. The whole organic matter pool reduced the translocation of pollutants downward the profile. The addition of HA enhanced this behaviour by increasing the PAH retention in the top layers (7.55 mg and 4.00 mg in the top two layers, respectively) while FA increased their mobility (only 2.30 and 2.90 mg of PAHs were found in the top layers) and favoured leaching. In fact, in the presence of HA alone, the higher amounts of PAHs retained at the surface and the good correlation (r2=0.936) between TOC and hydrocarbon distribution can be attributed to a parallel distribution of PAHs and HA, while in the presence of FA, the higher mobility of PAHs can be attributed to the high mobility of the humic material, as expected by its extensive hydrophilic characteristics.     

Investigation of organic matter dynamics during in-vessel composting of an aged coal-tar contaminated soil using fluorescence excitation-emission spectroscopy

In-vessel composting of an aged coal-tar contaminated soil from a manufactured gas plant site was investigated over 98days using laboratory-scale in-vessel composting reactors. The composting reactors were operated at 18 different operational conditions using a logistic three-factor factorial design with three temperatures (T=38, 55 and 70 degrees C), four soil to green waste ratios (S:GW; 0.6:1, 0.7:1, 0.8:1 and 0.9:1 on a dry weight basis) and three moisture contents (MC; 40%, 60% and 80%). Excitation-emission matrix (EEM) fluorescence spectroscopy was used to investigate organic matter dynamics in the composting mixture. The results of this investigation indicated that formation of humic substances can be monitored by fluorescence excitation-emission matrix, and provided evidence of progressive mineralization or humification of the composting mixture. Peak excitation wavelength shifts and peak fluorescence intensity can both be used as indicators to monitor the humification or maturation of compost. Finally, the fluorescence index can be applied to investigate the origin of humic substances and fulvic acids, and the humification or maturation of compost.     

Effect of organic amendments on the mobility of trace elements in phytoremediated techno-soils: role of the humic substances

The efficiency of aided phytostabilization using organic amendments such as ramial chipped wood (RCW) and composted sewage sludge (CSS) was studied on contaminated techno-soils, on nine experimental plots. The objective was to characterize the role of fulvic (FA) and humic acids (HA) on the mobilization of trace elements, specifically As, Cu, Mo, Pb and Zn. Results showed that the addition of CSS increased the total organic carbon and nitrogen content more than with RCW and as a result, the C/N ratio in the CSS soil was higher than in the RCW and non-amended (NE) soil, reflecting the high decomposition of soil organic matter in the CSS soil compared with the other soils. The RCW and CSS amendments increased the hydrogen index (HI) values and the oxygen index (OI) values compared with the NE soil, especially for the soil treated with CSS which contained more aliphatic than aromatic compounds. The addition of CSS to the techno-soil significantly increased the percentage of C _org associated with the HA fractions compared with the RCW and NE soils. The soil amended with CSS showed the highest E ₄/E ₆ ratio and the lowest E ₂/E ₃ ratio of FA. Zn and As were more abundant in the FA fraction than in the HA fraction, whereas Pb, Cu and Mo were more associated to HA than to FA in the treated and untreated soils, which may explain the difference in their mobility and availability.