醋渣和糠醛渣对赤泥中金属稳定性的影响

赤泥中和是实现堆场植被复垦的必要途径,而醋渣和糠醛渣是赤泥降碱和改良效果较好的2种生物质材料.针对赤泥碱性降低过程中理化性质的改变,根据MEP(多级提取程序)毒性溶出以及BCR形态分级试验,对醋渣和糠醛渣对赤泥中金属行为的影响进行了研究.结果表明:添加20%的醋渣和糠醛渣后,赤泥pH从10.60分别降至9.61和8.96,w(TOC)从8.04 g/kg分别增至35.11和38.62 g/kg,赤泥比表面积从10.18 m2/g分别降至7.36和8.57 m2/g,CEC(阳离子交换量)从106.28 cmol/kg分别增至127.19和161.59 cmol/kg;赤泥中Mo的最低浸出浓度为0.37 mg/L,超过GB/T 14848—1993《地下水质量标准》中Mo的Ⅲ类标准限值(0.1 mg/L);醋渣和糠醛渣可有效抑制赤泥中Al、V、Pb的浸出,但却可促进Cu、Mn、Ni和Mo的浸出,四者的最高浸出浓度分别可达64.45、17.64、12.09 μg/L和29.37 mg/L;醋渣和糠醛渣的添加可导致Al、V和Pb向稳定性较高的残渣态转化,Ni则向稳定性较低的酸可提取态转化.研究显示,糠醛渣比醋渣有更强的中和能力,对赤泥中金属稳定性影响较小.赤泥中金属元素具有潜在的长期浸出性且环境风险较高.      

赤泥碱性调控研究进展

赤泥是氧化铝工业生产过程产生的强碱性固体废弃物,资源化利用难、环境风险高,严重制约了氧化铝行业的可持续发展.赤泥土壤化是实现规模化处置赤泥的一种可行方法,而碱性调控则是赤泥土壤化的关键环节.论文在综述氧化铝生产过程碱性物质形成过程的基础上,从可溶性碱和化学结合碱角度分析了赤泥碱性物质的赋存状态,阐述了国内外化学调碱法和生物调碱法的研究进展和碱性转化机制,剖析了赤泥碱性调控方面存在的问题,提出了赤泥碱性调控研究的发展方向.这将为赤泥规模化处置和堆场生态重建、保障氧化铝工业的健康发展提供科学参考.     

Improvements on physical conditions of bauxite residue following application of organic materials

Soil formation and ecological rehabilitation is the most promising strategy to eliminate environmental risks of bauxite residue disposal areas. Its poor physical structure is nevertheless a major limitation to plant growth. Organic materials were demonstrated as effective ameliorants to improve the physical conditions of bauxite residue. In this study, three different organic materials including straw (5% W/W), humic acid (5% W/W), and humic acid-acrylamide polymer (0.2% and 0.4%, W/W) were selected to evaluate their effects on physical conditions of bauxite residue pretreated by phosphogypsum following a 120-day incubation experiment. The proportion of 2-1 mm macro-aggregates, mean weight diameter (MWD) and geometric mean diameter (GWD) increased following organic materials addition, which indicated that organic materials could enhance aggregate stability. Compared with straw, and humic acid, humic acid-acrylamide polymer application had improved effects on the formation of water-stable aggregates in the residues. Furthermore, organic materials increased the total porosity, total pore volume and average pore diameter, and reduced the micropore content according to nitrogen gas adsorption (NA) and mercury intrusion porosimetry (MIP) analysis, whilst enhancing water retention of the residues based on water characteristic curves. Compared with traditional organic wastes, humic acid-acrylamide polymer could be regarded as a candidate according to the comprehensive consideration of the additive amount and the effects on physical conditions of bauxite residue. These findings could provide a novel application to both Ca-contained acid solid waste and high-molecular polymers on ecological rehabilitation at disposal areas.     

Effect of amendments on the leaching behavior of alkaline anions and metal ions in bauxite residue

A column leaching experiment was used to investigate the efficacy of amendments on their ability to remove alkaline anions and metal ions from bauxite residue leachates. Treatments included, simulated acid rain(AR), phosphogypsum + vermicompost(PVC), phosphogypsum +vermicompost + simulated acid rain(PVA), and biosolids + microorganisms(BSM) together with controls(CK). Results indicated that amendment could effectively reduce the leachate pH and EC values, neutralize OH~-, CO_3~(2-), HCO_3~-, and water soluble alkali, and suppress arsenic(As)content. Correlation analysis revealed significant linear correlations with pH and concentrations of OH~-, CO_3~(2-), HCO_3~-, water-soluble alkali, and metal ions. BSM treatment showed optimum results with neutralizing anions(OH~-, CO_3~(2-), and HCO_3~-), water soluble alkali, and removal of metal ions(Al, As, B, Mo, V, and Na), which was attributed to neutralization from the generation of small molecular organic acids and organic matter during microbial metabolism. BSM treatment reduced alkaline anions and metal ions based on neutralization reactions in bauxite residue leachate, which reduced the potential pollution effects from leachates on the soil surrounding bauxite residue disposal areas.     

Variation on leaching behavior of caustic compounds in bauxite residue during dealkalization process

Bauxite residue, a byproduct of alumina manufacture, is a serious environmental pollutant due to its high leaching contents of metals and caustic compounds. Four typical anions of CO₃^2?, HCO₃^?, Al(OH)₄^? and OH^? (represented caustic compounds) and metal ions (As, B, Mo and V) were selected to assess their leaching behavior under dealkalization process with different conditions including liquid/solid ratio (L/S ratio), temperature and leaching time. The results revealed that washing process could remove the soluble composition in bauxite residue effectively. The leaching concentrations of typical anions in bauxite residue decreased as follows: c(CO₃^2?) > c(HCO₃^?) > c[Al(OH)₄^?] > c(OH^?). L/S ratio had a more significant effect on leaching behavior of OH^?, whilst the leaching concentration of Al(OH)₄^? varied larger underleaching temperature and time treatment. Under the optimal leaching, the total alkaline, soluble Na concentrations, exchangeable Ca concentrations were 79.52, 68.93, and 136.0 mmol/L, respectively, whilst the soluble and exchangeable content of As, B, Mo and V in bauxite residue changed slightly. However, it should be noted that water leaching has released metal ions such as As, B, Mo and V in bauxite residue to the surrounding environment. The semiquantitative analysis of XRD revealed that water leaching increased the content of gismondine from 2.4% to 6.4%. The SEM images demonstrated the dissolution of caustic compounds on bauxite residue surface. The correlation analysis indicated that CO₃^2? and HCO₃^? could effectively reflect the alkalinity of bauxite residue, and may be regarded as critical dealkalization indicators to evaluate alkalinity removal in bauxite residue.     

菌渣改良淤泥固化土及其促进黑麦草的生长

针对淤泥固化土板结程度高,养分不足等缺陷,采用菌渣辅以MgSO₄,通过物理掺和的方式改良固化土,用于园林绿化利用。通过对菌渣改良土的物理性状特性和养分含量分析、黑麦草种子发芽实验和盆栽实验,探究了菌渣掺量和粒径对淤泥固化土改良的影响。结果表明:淤泥固化土掺入40 g/kg的5~10 mm菌渣和0.2 g/kg MgSO₄后改良效果最佳,黑麦草株高增加了32.3%,干重提高了126.7%。菌渣的疏松多孔可改善土壤孔隙结构、降低土壤容重、提升土壤保水性;MgSO₄补充了缺失的有效镁和有效硫;菌渣自身的营养物质提升了土壤有机质、水解性氮、有效磷、速效钾等养分含量,进而提高土壤保肥能力。菌渣可作为土壤改良剂实现淤泥固化土的低成本改良利用。     

黄河源区斑块化退化高寒草甸土壤微生物多样性对长期封育的响应

为了明确黄河源区斑块化退化高寒草甸土壤细菌和真菌群落对长期封育的响应特征,通过对土壤理化性质分析和高通量测序技术,对1年期(E1)、短期(E4)和长期(E10)围栏封育下土壤pH、含水量、养分和微生物群落组成及多样性进行分析.结果表明,E1封育显著降低土壤pH,而长短期封育均显著提高土壤pH,长期封育能显著提高土壤含水量和全氮含量,短期封育能显著提高土壤速效磷含量.长期封育能显著提高细菌变形菌门(Proteobacteria)和真菌子囊菌门(Ascomycota)相对丰度,短期封育能显著提高细菌酸杆菌门(Acidobacteriota)相对丰度,但长短期封育均使真菌担子菌门(Basidiomycota)相对丰度下降;随着封育年限的延长,细菌的Chao1和Shannon多样性指数呈增加趋势,长短期封育无显著差异,真菌的Chao1指数逐渐增加,Shannon多样性指数先增加后减小,长短期封育无显著差异.冗余分析(RDA)表明,围栏封育主要通过改变土壤pH和含水量来改变微生物群落组成和结构.因此,E4短期封育能明显改善斑块化退化高寒草甸的土壤理化性质和微生物多样性,无需进行长期封育,否则会造...     

Is the availability of different nutrients a critical factor for the impact of bacteria on subterraneous carbon budgets?

Bacteria thriving in underground systems, such as karsts, adapt to use a variety of nutrients. Most of these nutrients derive from superficial processes. This study shows that bacteria are able to differentially induce carbonate precipitation or dissolution depending on the availability of nutrients for growth. Different bacterial strains isolated from caves, representing the most common components of these microbial communities, were cultured with different carbon and nitrogen sources (e.g., acetate, glucose, peptone, humic acids) and induced changes in pH were measured during growth. Carbonate can either precipitate or dissolve during bacterial growth. The induction of carbonate precipitates or their dissolution as a function of consumption of specific carbon sources revealed the existence of an active nutrient cycling process in karsts and links nutrients and environmental conditions to the existence of a highly significant carbon sink in subterraneous environments.     

铜尾矿库坝面土壤微生物群落动态的驱动因子

随机过程和确定性过程对群落动态的影响机制及重要性是群落生态学研究的中心课题,也是目前群落生态学最具争议的问题.微生物群落在生态系统物质循环和能量流动过程中发挥着重要作用,对其结构动态的研究不仅为阐明群落构建机制提供重要的数据支持,而且为预测环境胁迫条件下微生物群落结构的动态提供理论依据.本研究通过Illumina MiSeq测序的方法,分析了中条山十八河尾矿库坝面不同恢复阶段细菌和真菌群落结构特征.结果表明,研究区尾矿坝不同恢复年限土壤理化性质发生梯度变化,植物群落结构呈现一定的演替趋势,植物群落多样性与土壤养分显著相关,而与土壤重金属含量无相关性.不同恢复年限的土壤微生物群落结构具有显著差异,其中优势细菌主要有变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、厚壁菌门（Firmicutes）、酸杆菌门（Acidobacteria）;优势真菌主要有子囊菌门（Ascomycota）、担子菌门（Basidiomycota）、接合菌门（Zygomycota）.微生物群落组成主要受到土壤养分和重金属含量的影响,而植物多样性对微生物群落结构的影响不明显,表明在局域小尺度环境胁迫条件下,土壤环境因子是微生物群落结构动态变化的主要驱动力.     

土壤微生物群落对玉米根茬和茎叶残体碳的利用特征

以沈阳农业大学连续29a棕壤长期定位施肥试验为基础,以¹³C标记的玉米植株为试验试材,采用田间原位培养方法和磷脂脂肪酸-稳定同位素示踪联用（PLFA-SIP）技术,研究土壤不同粒级团聚体中微生物群落对残体碳的同化状况,及土壤有机碳的固定这一关键生物地球化学过程.结果表明：植物残体添加显著增加了全土及各粒级团聚体中各微生物群落PLFAs含量,其中以真菌PLFAs含量增幅最高,细菌中以革兰氏阴性菌含量增幅最高;但不同残体类型并未对全土中各群落PLFAs含量产生显著影响.茎叶碳与根茬碳的矿化率无显著差异;根茬碳对总PLFAs碳库的贡献是茎叶碳的3.9倍,说明根茬碳更有利于通过微生物合成的方式贡献于土壤有机碳库.残体碳占不同微生物群落PLFAs碳库的比例以真菌最高,表明真菌对植物残体碳具有最强的同化能力;而残体碳对PLFAs的贡献在革兰氏阳性菌和革兰氏阴性菌之间却差异不大.残体碳含量、PLFAs含量和残体碳占微生物PLFAs碳库的比例均在较小粒级的团聚体中（0.25~1mm和<0.25mm）更高,而细菌/真菌比在较大粒级团聚体（>2mm和1~2mm）中更高,说明较小粒级团聚体已经成为微生物对残体进行同化固定的主要位点.植物残体在土壤中的腐解过程与残体类型、土壤团聚体组成和微生物群落密切相关.     

深圳市餐饮垃圾收运处置规划研究

文章对深圳市餐饮垃圾单独收运处置进行了规划研究,规划年限2006-2020年.通过对深圳市餐饮垃圾的产生、收运处置现状及存在的问题分析,提出了餐饮垃圾的收运模式以及采用厌氧消化制沼气的处置方式.此外,还提出了深圳市餐饮垃圾的管理建设思路.     

Bacterial succession in epiphytic biofilms and deciduous layer sediments during Hydrilla verticillata decay: A field investigation

Submersed macrophytes decay is an important natural process and has important role in mass and energy flow in aquatic ecosystems. However, little is known about the dynamical changes in nutrients release and bacterial community during submersed macrophyte decay in natural environment. In this study, a field observation was conducted in a wetland dominated with Hydrilla verticillata for 36 days. Increase of H₂O₂ and malondialdehyde (MDA) content and decrease of soluble proteins concentration were detected in leaves during H. verticillata decay. Meanwhile, ammonium-N, soluble microbial products (SMP) and TOC concentration increased in overlying water. According to bacterial 16S rRNA Illumina sequencing analysis, the Shannon values were lower in epiphytic biofilms than deciduous layer sediments. The relative abundances of Proteobacteria, Cyanobacteria and Actinobacteria were higher in epiphytic biofilms than in deciduous layer sediments (P < 0.05). Co-occurrence network analyses showed that a total of 578 and 845 pairs of correlations (|r| > 0.6) were identified from 122 and 112 genera in epiphytic biofilms and deciduous layer sediments, respectively. According to co-occurrence patterns, eight hubs were mainly from phyla Proteobacteria, Acidobacteria and Parcubacteria in epiphytic biofilms; while 37 hubs from the 14 phyla (Proteobacteria, Bacteroidetes, Acidobacteria, Chloroflexi, et al.) were detected in deciduous layer sediments. Our results indicate that bacterial community in deciduous layer sediments was more susceptible than in epiphytic biofilms during decay process. These data highlight the role of microbial community in deciduous layer sediments on nutrients removal during H. verticillata decay and will provide useful information for wetland management.     

微生物发酵菌和生物质炭及蘑菇渣对污泥堆肥效果的影响

为解决污泥的处理处置难题,实现污泥减量化、无害化和资源化,在污泥中添加蘑菇渣、微生物发酵菌和生物质炭等辅料,进行共堆肥试验,设置T1（不添加辅料）、T2（添加30%的园林枯枝）、T3（添加20%的园林枯枝、9.9%的蘑菇渣和0.1%的微生物发酵菌）、T4（添加20%的园林枯枝和10%的生物质炭）,以及T5（添加20%的园林枯枝、4.9%的蘑菇渣、0.1%的微生物发酵菌和5%的酸化生物质炭）5个好氧堆肥处理,考察各处理堆肥过程中温度变化、肥料的理化特性以及GI（发芽指数）.结果显示:①T5处理的效果最好,堆肥至第3天,堆体温度达到70.5℃,并且温度不低于50℃的时间达到19 d. ②T5处理肥料的w（TKN）（TKN为总凯氏氮）、w（TP）和w（TK）均最高,分别达到3.88、0.64和1.10 g/kg,远高于其他4个处理;产品的GI随堆肥时间的延长逐渐增长,达到183%. ③T5处理的NH₃排放最少,氮元素流失最低,能最大程度的转化成固化无机氮;残渣态重金属含量最高,不易浸出到环境中进入生态系统,生物毒性低.研究显示,蘑菇渣、微生物发酵菌和生物质炭能够促进污泥的腐熟,减少二次污染的产生,产品质量较好.      

Accelerated alkalinity regulation and long-term dry-wet aging durability for bauxite residue remediated with biomass pyrolysis

Biomass fermentation provides a potential route toward the ecological disposal for the bauxite residue（BR） with high alkalinity issues. However, how to accelerate the remediation of the alkaline problem with a long-term durability is still a big challenge. Herein, we investigated the acceleration of the decomposition of straw toward organic acid species via a pyrolysis strategy as well as the pH stability during long-term dry-wet aging for the treated BR. The pH of pyrolytic BR at 300 °C is stab...     

土壤微生物群落对玉米根茬和茎叶残体碳的利用特征

以沈阳农业大学连续29a棕壤长期定位施肥试验为基础,以¹³C标记的玉米植株为试验试材,采用田间原位培养方法和磷脂脂肪酸-稳定同位素示踪联用（PLFA-SIP）技术,研究土壤不同粒级团聚体中微生物群落对残体碳的同化状况,及土壤有机碳的固定这一关键生物地球化学过程.结果表明：植物残体添加显著增加了全土及各粒级团聚体中各微生物群落PLFAs含量,其中以真菌PLFAs含量增幅最高,细菌中以革兰氏阴性菌含量增幅最高;但不同残体类型并未对全土中各群落PLFAs含量产生显著影响.茎叶碳与根茬碳的矿化率无显著差异;根茬碳对总PLFAs碳库的贡献是茎叶碳的3.9倍,说明根茬碳更有利于通过微生物合成的方式贡献于土壤有机碳库.残体碳占不同微生物群落PLFAs碳库的比例以真菌最高,表明真菌对植物残体碳具有最强的同化能力;而残体碳对PLFAs的贡献在革兰氏阳性菌和革兰氏阴性菌之间却差异不大.残体碳含量、PLFAs含量和残体碳占微生物PLFAs碳库的比例均在较小粒级的团聚体中（0.25~1mm和<0.25mm）更高,而细菌/真菌比在较大粒级团聚体（>2mm和1~2mm）中更高,说明较小粒级团聚体已经成为微生物对残体进行同化固定的主要位点.植物残体在土壤中的腐解过程与残体类型、土壤团聚体组成和微生物群落密切相关.     

喀斯特地区典型风化剖面重金属超标程度及元素迁移特征研究

我国西南喀斯特地区是著名的重金属元素地球化学异常区。除了人类活动所导致的土壤污染问题以外,地质背景很可能是造成土壤重金属超标的重要因素。为了弄清岩石风化和成土过程中重金属的释放规律及其环境效应,本次研究以贵州省罗甸县典型的碳酸盐岩和碎屑岩风化剖面为载体,采用实地调查、地球化学测试分析等手段,结合质量平衡系数的计算方法对研究剖面的重金属元素超标程度及元素迁移规律展开调查。研究结果表明:碳酸盐岩比泥质岩具有更高的重金属元素释放潜能,其风化和成土过程向环境中释放重金属的量与风化壳的发育程度有关。研究区石灰土剖面重金属元素超标程度严重,且以Cd和As的超标程度最大。地带性黄壤中Cr、Ni元素的富集很可能与剖面发育过程中铁氧化物的沉淀富集有关。综合分析认为岩性不同所导致的风化速率的差异很可能是造成碳酸盐岩和泥质岩剖面重金属淋失程度差异的主要原因。而且,重金属元素在风化剖面中的迁移规律受元素自身地球化学性质、母岩类型和风化壳发育程度等多重因素控制。     

矿区土壤中砷污染对微生物群落的影响研究

采用梯度培养和PCR-DGGE技术,对大柳塔矿区矸石山及周边土壤的砷含量及其对土壤微生物群落的影响进行了研究,并通过测序研究了土壤微生物群落的结构。结果表明,矸石山及其周边自然表土的含水量较少,且十分相近;全磷和有机质含量普遍较高,p H呈中偏碱性;不同风化程度矸石山土壤砷含量对土壤微生物群落有显著的影响,不同砷污染负荷土壤中微生物群落的丰度存在差异;矸石山复垦年限不同,土壤理化性质会发生变化;土壤中砷含量的增高,对植物生长起关键作用的Gemmatimonas(甲烷单毛菌属)等微生物群落受到不同程度的抑制;Proteobacterium(变形菌门)具有较强的耐砷性;矸石山土壤特有的理化性质可为GASP-WA2W2_F11等微生物群落的演替创造了条件。     

山西兴县铝土岩的地球化学特征

研究了山西省兴县铝土岩中的主要元素和微士元素的富集规律及与下伏基岩的关系，认为该铝土岩是由下伏碳酸盐岩和页岩风化而形成的。     

广西某赤泥堆场周边土壤重金属污染风险

为考察广西典型赤泥堆场周边农田土壤重金属污染环境风险,采集194个表层土壤样品,运用内梅罗综合指数法、Harkanson潜在生态危害指数法分析重金属污染状况,利用空间插值法、主成分分析法等对8种重金属元素进行源解析.结果表明,除V、Cu,其他元素的平均含量均超过广西区背景值,Cr、Ni、Zn、As、Pb、Co平均含量超过广西区土壤背景值倍数,分别为1.69、1.35、2.45、11.83、4.17、1.95,其中As为首要污染物;农田土壤呈现出"中度"生态风险,As的贡献率高达68%.8种重金属空间分布特征整体有一定相似之处,均在赤泥库东北方向和西南方向浓度较高,而在东南方向整体浓度较低,并非下风向的西北方向,仅Cr在西北角出现明显富集,可能受到赤泥库影响.农田重金属污染源不同,As污染主要受人为因素影响,V、Ni、Cu、Zn、Pb、Co主要受到自然成土母质的影响,Cr同时受到成土母质和人为因素的影响.     

Characterization of bacterial community dynamics in a full-scale drinking water treatment plant

Understanding the spatial and temporal dynamics of microbial communities in drinking water systems is vital to securing the microbial safety of drinking water. The objective of this study was to comprehensively characterize the dynamics of microbial biomass and bacterial communities at each step of a full-scale drinking water treatment plant in Beijing, China. Both bulk water and biofilm samples on granular activated carbon (GAC) were collected over 9 months. The proportion of cultivable cells decreased during the treatment processes, and this proportion was higher in warm season than cool season, suggesting that treatment processes and water temperature probably had considerable impact on the R2A cultivability of total bacteria. 16s rRNA gene based 454 pyrosequencing analysis of the bacterial community revealed that Proteobacteria predominated in all samples. The GAC biofilm harbored a distinct population with a much higher relative abundance of Acidobacteria than water samples. Principle coordinate analysis and one-way analysis of similarity indicated that the dynamics of the microbial communities in bulk water and biofilm samples were better explained by the treatment processes rather than by sampling time, and distinctive changes of the microbial communities in water occurred after GAC filtration. Furthermore, 20 distinct OTUs contributing most to the dissimilarity among samples of different sampling locations and 6 persistent OTUs present in the entire treatment process flow were identified. Overall, our findings demonstrate the significant effects that treatment processes have on the microbial biomass and community fluctuation and provide implications for further targeted investigation on particular bacteria populations.