氧化亚铁硫杆菌对黄铜矿的生物氧化研究

针对矿区硫化矿氧化产生的酸性矿山废水(AMD)对生态环境造成严重影响的问题,以矿区常见的黄铜矿(CuFeS2)为研究对象,采用已筛选的氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,简称A.f菌)为实验菌株,探讨在A.f菌作用下黄铜矿的氧化过程。实验结果表明,A.f菌可显著促进黄铜矿的氧化,第18天有菌体系中的铜离子浓度是无菌体系中的5倍;同时细菌可促进溶液中Fe2+氧化为Fe3+,使氧化还原电位升高,从而对黄铜矿保持较高的氧化速率,并导致体系的pH值降低;还发现黄铜矿的氧化过程中可形成中间产物方黄铜矿(CuFe2S3),而细菌氧化还可产生硫磷化钴(CoPS),中间产物的形成并没有明显延缓黄铜矿的氧化速率;生物氧化可造成矿样表面侵蚀多坑,可能是细菌对黄铜矿的直接氧化作用造成的。由于黄铜矿的生物氧化明显控制其氧化进程,抑制黄铜矿的生物氧化对酸性矿山废水的源头治理具有十分重要的意义。     

硫酸盐还原菌包覆矿石控制酸性废水排放及碳源的优选研究

本研究基于实验室筛选、培养的硫酸盐还原菌(Sulfate-reducing bacteria,简称SRB)菌群,分别考察以麦芽糊精、污泥、乙醇、乳酸钠等为碳源时SRB的生长状况,同时模拟野外环境进行柱淋滤实验,分析在不同碳源作用下原位控制酸性矿山废水的效果.结果表明,采用这4种碳源时,SRB还原硫酸盐能力的大小依次为:...     

Response of Fish and Macroinvertebrate Bioassessment Indices to Water Chemistry in a Mined Appalachian Watershed

Multimetric indices based on fish and benthic macroinvertebrate assemblages are commonly used to assess the biological integrity of aquatic ecosystems. However, their response to specific stressors is rarely known. We quantified the response of a fish-based index (Mid-Atlantic Highlands Index of Biotic Integrity, MAH-IBI) and a benthic invertebrate-based index (West Virginia Stream Condition Index, WV-SCI) to acid mine drainage (AMD)-related stressors in 46 stream sites within the Cheat River watershed, West Virginia. We also identified specific stressor concentrations at which biological impairment was always or never observed. Water chemistry was extremely variable among tributaries of the Cheat River, and the WV-SCI was highly responsive across a range of AMD stressor levels. Furthermore, impairment to macroinvertebrate communities was observed at relatively low stressor concentrations, especially when compared to state water quality standards. In contrast to the WV-SCI, we found that the MAH-IBI was significantly less responsive to local water quality conditions. Low fish diversity was observed in several streams that possessed relatively good water quality. This pattern was especially pronounced in highly degraded subwatersheds, suggesting that regional conditions may have a strong influence on fish assemblages in this system. Our results indicate that biomonitoring programs in mined watersheds should include both benthic invertebrates, which are consistent indicators of local conditions, and fishes, which may be indicators of regional conditions. In addition, remediation programs must address the full suite of chemical constituents in AMD and focus on improving linkages among streams within drainage networks to ensure recovery of invertebrate and fish assemblages. Future research should identify the precise chemical conditions necessary to maintain biological integrity in mined Appalachian watersheds.     

Geochemical Characteristics of the Acid Mine Drainage in the Water System in the Vicinity of the Dogye Coal Mine in Korea

This study investigated geochemical characteristics of the acid mine drainage (AMD) discharged from the abandoned mine adits in the vicinity of the Dogye coal mine in Korea. Acid mine drainage discharged from Jeoncha pit adit of the Dogye coal mine, which is the main source of the AMD in the study area, had a pH value of 3.0 and concentrations of 2148mg SO₄ ^2– L^–1, 229mg Fe L^–1, 71mg A1 L^–1 and 11mg Mn L^–1. The reduction of some metal concentrations downstream from the discharge point could be explained on the basis of dilution and precipitation. The order of removal of metal ions downstream from the discharge point was Fe>A1, Cu>Zn, Mn. Acidity could be used as a good determining factor offering comprehensive and quantitative values for the polluting extent of acid mine drainage. The acidities existing in all acidic water samples in the Gunahan district originated primarily from mineral acidity, especially in the upper Nahan Creek from dissolved Fe and Al and in the middle and down Nahan Creek from dissolved Al. From the application of the WATEQ4F program, it was determined that predominant species of dissolved Fe in all water samples was Fe²⁺, and those of dissolved Al were AlSO₄ ⁺ and Al³⁺ except for IW2 sample which was associated with white precipitates. The species of dissolved Al in IW2 sample include also AlOH²⁺ and Al(OH)₂ ⁺. The saturation indices of goethite and haematite were positive in the water samples associated with ochrous precipitates (usually called Yellow Boy), therefore these solids might be precipitated. For the IW2 sample, the saturation indices of amorphous Al(OH)₃ and gibbsite were positive, so theoretically these solids might also be precipitated. By XRD analysis, it was found that goethite occurs in ochrous precipitates, and gibbsite in white precipitates.     

Untersuchungskonzept zur Charakterisierung toxischer Stoffe in belastetem Wasser

Zusammenfassung  Zur ?kotoxikologischen Beurteilung von belastetem Wasser werden h?ufig einfache Biotests eingesetzt. Nicht selten werden dabei toxische Effekte festgestellt. Es stellt sich dann die Frage nach den verantwortlichen Wasserinhalts-stoffen. Durch Festphasenextraktion (SPE) werden diese angereichert, gewonnen und dünnschichtchromatographisch unter Verwendung der automatisierten Mehrfachentwicklung aufgetrennt. Von der DC-Platte wird ein Streifen abgetrennt und darauf direkt die biologische Detektion mit Mikroorganismen (Bacillus subtilis, Leuchtbakterien) durchgeführt. Dadurch k?nnen toxische Banden erkannt werden, Auf dem DC-Plattenrest wird von der toxischen Bande mit einem DC-scanner ein UV-Spektrum aufgenommen, die entsprechende Bande herausgekratzt, der toxische Stoff eluiert und infrarotspektroskopisch untersucht. Durch Spektrenvergleich gelingt es meistens, den Stoff zu charakterisieren. In der vorliegenden Arbeit wird am Beispiel eines Zitzengummieluates das Analysenkonzept vorgestelit. Es zeigte sich, dass dieser Gummiartikel einen Vulkanisationsbeschleuniger (2-Mercaptobenzothiazol) freisetzt. Online-Publikation am: 21.12.1999     

Bioremediation of Acidic and Metalliferous Drainage (AMD) through organic carbon amendment by municipal sewage and green waste

Pit lakes (abandoned flooded mine pits) represent a potentially valuable water resource in hot arid regions. However, pit lake water is often characterised by low pH with high dissolved metal concentrations resulting from Acidic and Metalliferous Drainage (AMD). Addition of organic matter to pit lakes to enhance microbial sulphate reduction is a potential cost effective remediation strategy. However, cost and availability of suitable organic substrates are often limiting. Nevertheless, large quantities of sewage and green waste (organic garden waste) are often available at mine sites from nearby service towns. We treated AMD pit lake water (pH 2.4) from tropical, North Queensland, Australia, with primary-treated sewage sludge, green waste, and a mixture of sewage and green waste (1:1) in a controlled microcosm experiment (4.5 L). Treatments were assessed at two different rates of organic loading of 16:1 and 32:1 pit water:organic matter by mass. Combined green waste and sewage treatment was the optimal treatment with water pH increased to 5.5 in only 145 days with decreases of dissolved metal concentrations. Results indicated that green waste was a key component in the pH increase and concomitant heavy metal removal. Water quality remediation was primarily due to microbially-mediated sulphate reduction. The net result of this process was removal of sulphate and metal solutes to sediment mainly as monosulfides. During the treatment process NH(3) and H(2)S gases were produced, albeit at below concentrations of concern. Total coliforms were abundant in all green waste-treatments, however, faecal coliforms were absent from all treatments. This study demonstrates addition of low-grade organic materials has promise for bioremediation of acidic waters and warrants further experimental investigation into feasibility at higher scales of application such as pit lakes.     

以稻草和污泥为碳源硫酸盐还原菌处理酸性矿山排水

以污泥为硫酸盐还原菌(SRB)接种菌群,分别添加等量稻草和乙醇,研究了SRB以不同碳源处理酸性矿山排水(pH=2.5)的过程及不同碳源对硫酸盐还原和重金属去除的影响.结果表明,在无外加中和剂的情况下,污泥中的碱性物质可在反应开始的1 d内迅速中和酸性矿山排水的部分酸度,使反应体系pH值从2.5升至5.4～6.3,利于SRB的生长.污泥中含少量易被微生物分解的有机物,体系中仅含污泥时,SO24-还原率最低(65.9%).添加稻草可促进SO24-还原(79.2%),因为污泥中的水解菌加速稻草分解,为SRB提供相对充足的碳源.添加乙醇为对照试验的体系中SO24-还原率最高(97.9%).含污泥的反应体系Cu2+去除率均高于99%,SRB驯化前Cu2+的去除主要归因于污泥的吸附作用.以稻草和污泥为碳源可实现低成本酸性矿山排水处理,对矿山环境的原位修复有实际意义.     

AMD铁絮体改性生物炭对重金属吸附机理研究 ——以Pb(II)为例

以酸性矿山废水生成的铁絮体和秸秆生物炭为原料,采用化学改性和紫外辐射联用技术制备改性生物炭,并通过正交试验确定最佳改性条件,同时利用FTIR、SEM和BET等方法对吸附材料的形貌特征、孔隙结构及其表面化学性质进行表征.结果表明,通过改性使吸附材料比表面积增大,吸附位点增多,在25℃、pH为7时,吸附材料改性后比表面积为295.71 m²·g^-1,对Pb（II）的拟合吸附量可达278 mg·g^-1.改性材料对Pb（II）的吸附过程符合Langmuir吸附等温线模型和准二级动力学模型,主要为单分子层吸附,受化学吸附控制.     

AMD对岩溶区旱地土壤理化性质及土壤酶活性的影响

煤矿开采产生的酸性矿山废水（ AMD ）已导致周边土壤受到了严重的污染。以贵州典型的喀斯特地区旱地土壤为研究对象,通过添加不同污染浓度的AMD,模拟AMD持续污染下,岩溶区旱地土壤pH、Eh、EC、Fe、Mn、Cu、Zn、SO2-4以及脲酶、微生物量的变化情况,进而评价AMD持续污染对岩溶区旱地土壤的影响。结果表明：随着AMD污染程度的持续增加,土壤Mn、Zn及脲酶活性在较低污染程度下急剧升高,在较高污染程度下则又显著降低,其中土壤Zn、脲酶活性随AMD浓度增加达到极显著水平（ p﹤0.01）;土壤pH有明显下降趋势（ p﹤0.01）,总体维持在6.5以上的较高水平;土壤Eh、EC、Fe、Cu、SO2-4随AMD污染程度的增加呈显著、极显著的增大趋势（ p均﹤0.05）;土壤微生物量则随AMD污染程度的增加呈显著的降低趋势（ p﹤0.05）。综上表明,AMD的持续污染将对岩溶区煤矿周边的旱地土壤造成严重的影响。     

Application of artificial neural networks for classification of uranium distribution in the Central Rand goldfield,South Africa

Mine tailings generate significant environmental impacts and contribute to water pollution. The Central Rand goldfield, South Africa is replete with gold mine tailings which have contributed significantly to water pollution as a result of acid mine drainage (AMD). Water quality is affected by mine tailings and spillages, especially from active slimes dams, currently reprocessed tailings, as well as footprints left behind after reprocessing. The release and distribution of uranium from these sites was studied. Correlation matrices show a strong link between different variables as a result of AMD produced. Principal component analysis (PCA) was used to identify very influential variables which account for the pollution trends. Artificial neural networks (ANN) using the Kohonen algorithm were applied to visualise these trends and patterns in the distribution of uranium. High concentrations of this radionuclide were detected in streams in the vicinity of the tailings dumps, active slimes and reprocessing areas. The concentrations are reduced drastically in dams and wetlands as a result of precipitation and dilution effects.