污泥中重金属的生物淋滤

生物淋滤法(Bioleaching)是指利用自然界中一些微生物(硫细菌)的直接作用或其代谢产物的间接作用,产生氧化、还原、络合、吸附或溶解反应,将固相中某些不溶性成分(如重金属、硫及其他金属)分离浸提出来的技术.在生物淋滤中,嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,A.f)和嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans,A.f)被用作有效的淋滤载体[1].这种嗜酸性的化能自养型细菌以大气中的CO2为碳源,以无机物铁或硫为能源来维持生长,不需要提供外来的碳源和电子供体.另外,由于pH值很低,抑制了其他细菌的生长,所以在实际的操作过程中不需要严格的无菌条件.氧化亚铁硫杆菌和氧化硫硫杆菌去除重金属适宜于污水处理厂的开放系统,采用土著嗜酸性氧化亚铁硫杆菌(A.f)和氧化硫硫杆菌(A.f)进行重金属去除.也就是说,处理什么地方的污泥,就在什么地方分离A.f和A.t,这样分离的微生物在生物淋滤过程中能发挥较好的作用.这也是微生物在自然界生长繁殖的特点之一. 本期介绍了王聪、宋存江等[2]从剩余活性污泥中分离得到两株土著硫杆菌,对两株菌进行了分类鉴定,确定二者分别为嗜酸性氧化亚铁硫杆菌杆(Acidithiobacillus ferrooxidans,A.f)和嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans,A.t),将二者的单菌和混合菌分别接种于剩余活性污泥中,进行了为期9 d的生物淋滤,对淋滤过程中的pH变化、氧化还原电位(ORP)以及重金属含量进行了检测.结果表明,生物淋滤9 d的混合菌对于As、Cr、Cu、Ni和Zn的去除效果最好,去除率分别达到了96.09%、93.47%、98.32%、97.88%和98.60%.混合菌生物淋滤对于Cd和Pb的去除率在第6天之后迅速下降,但是A.t单菌淋滤保持较高的去除率,此结果为进一步的应用打下了良好的基础.     

柠檬酸、草酸和乙酸对污泥中镉、铅、铜和锌的去除效果

研究了柠檬酸、草酸和乙酸对污泥中Cd、Pb、Cu和Zn等重金属的去除效果,并分析了污泥中重金属的形态变化和生物有效性.结果表明,随着反应时间和酸浓度的增加,污泥中重金属（Cu除外）的去除率也相应增加.污泥加入柠檬酸溶液反应7 h即可去除污泥中52.0%的Pb和74.2％的Zn, 24 h后可去除76.0%的Pb和92.5%的Zn,草酸和乙酸对重金属的去除率较低.柠檬酸去除的Pb和Zn主要以稳定态存在,并导致污泥中不稳定态重金属的比例上升,其中可交换态重金属浓度有不同程度的增加.虽然有机酸对Cd和Cu的去除率较低,但反应后可交换态Cd和Cu的浓度仍有小幅增加.     

柠檬酸、草酸和乙酸对污泥中镉、铅、铜和锌的去除效果

研究了柠檬酸、草酸和乙酸对污泥中Cd、Pb、Cu和Zn等重金属的去除效果,并分析了污泥中重金属的形态变化和生物有效性.结果表明,随着反应时间和酸浓度的增加,污泥中重金属（Cu除外）的去除率也相应增加.污泥加入柠檬酸溶液反应7h即可去除污泥中52.0%的Pb和74.2%的Zn,24h后可去除76.0%的Pb和92.5%的Zn,草酸和乙酸对重金属的去除率较低.柠檬酸去除的Pb和Zn主要以稳定态存在,并导致污泥中不稳定态重金属的比例上升,其中可交换态重金属浓度有不同程度的增加.虽然有机酸对Cd和Cu的去除率较低,但反应后可交换态Cd和Cu的浓度仍有小幅增加.     

异养微生物在金属生物淋滤技术中的应用

生物淋滤技术主要应用于低品位矿石金属选矿、煤气脱硫、废弃物中金属回收和污染介质中金属离子毒性的去除等方面。作为生物淋滤技术中的主体微生物之一,异养微生物可通过其产生的酸性代谢物还原、酸化及络合,提取或者溶解非硫化矿、固体废弃物、污水污泥及土壤中的金属,有助于解决目前的资源短缺问题,还可对污染环境治理提供技术支持,具有重要的理论意义和实践价值。应用于异养微生物淋滤技术中的常见微生物包括细菌(以假单胞菌为主)和真菌(以曲霉菌和青霉菌应用最为广泛)。淋滤过程涉及酸解、络合、还原及碱化等。目前,异养微生物淋滤技术主要应用于生物冶金、固体废弃物处理、污水处理和污染土壤修复等。本文分析了异养微生物金属淋滤过程中的问题,并提出了未来研究的发展方向。     

治理重金属污染河流底泥的生物淋滤技术

治理重金属污染河流底泥的生物技术是指利用生物体来消除或降低重金属毒性的方法,包括微生物修复、植物修复和植物.微生物联合修复,具有成本低、去除效率高、脱毒后污泥脱水性能好等优点,近年来在国际上备受关注.本文介绍了近10年来生物技术在治理重金属污染河流底泥方面的研究成果,着重介绍了日益受关注的生物淋滤技术,从微生物学、分子生物学和生物表面活性剂等方面的发展作了详细描述,展望了生物修复在河流底泥重金属污染应用中的前景.     

一株黑曲霉的筛选及其对河道底泥重金属的生物淋滤去除

生物淋滤,特别是异养生物淋滤,是最有前景的污染介质重金属绿色消减方式,但在污染底泥的处理中还没有得到广泛应用。本研究采集沈阳细河疏浚底泥,并从中筛选得到高效淋滤丝状真菌SY1,经形态学及ITS r DNA基因序列分析鉴定为黑曲霉,命名为Aspergillus niger SY1,测定了其生长特性,采用摇瓶培养法去除污染底泥中重金属的效果。结果表明:细河底泥受到重金属Cd污染最为严重,含量为33.3 mg·kg~(-1),且以生物可利用态为主;SY1最适合的温度为25～35℃,最适合初始pH值为6.0～7.0;该菌株生长代谢过程中产生葡萄糖酸和草酸,最高分别达14.7和6.4 g·L~(-1)。在最优条件下(底泥浓度为20g·L~(-1)、糖浓度为100 g·L~(-1)、孢子浓度为2×10~7个·m L~(-1)),经过SY1 8天的淋滤,底泥中Cd、Pb、Cu和Zn淋出率分别为93.5%、11.4%、62.3%和68.2%。因此,SY1是比较有潜力的重金属底泥淋滤菌株,可用于重金属污染疏浚底泥的淋滤修复。     

底物种类和浓度对污泥重金属生物淋滤效果的影响

以生污泥为材料,研究单质硫(浓度分别为5、10、20 g/L)、FeSO4?7H2O (浓度分别为10、20 g/L）和硫代硫酸钠（浓度分别为10、20 g/L）三种底物的不同浓度对污泥中Zn、Cu、Pb、Cd、Cr和Ni六种重金属生物淋滤效果的影响。结果表明：单质硫的致酸性最好,第4天pH值就达到2.0左右,Zn、Cu、Pb、Cr和Ni的滤出量最大（原污泥Cd未检出）,并以底物投放浓度在10～20 g/L为佳。FeSO4?7H2O的致酸性和重金属滤出量较单质硫弱。硫代硫酸钠在浓度10 g/L时,致酸性和重金属的滤出量介于单质硫和FeSO4?7H2O之间,但浓度20 g/L时滤液呈碱性,重金属难于滤出甚至不滤出。     

生物淋滤法去除污泥中的重金属

本研究从剩余活性污泥中分离得到两株土著硫杆菌。对两株菌进行了分类鉴定。确立二者分别为嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans, A. f)和嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans, A. t)。将二者的单菌和混合菌分别接种于剩余活性污泥中, 进行了为期9 d的生物淋滤, 对淋滤过程中的pH变化、氧化还原电位(ORP)以及重金属含量进行了检测。结果表明, 生物淋滤9 d混合菌对于As、Cr、Cu、Ni和Zn的去除效果最好; 去除率分别达到了96.09%、93.47%、98.32%、97.88%和98.60%。对于Cd和Pb混合菌生物淋滤的去除率在第6天之后迅速下降, 但是A. t单菌淋滤保持较高的去除率。     

剩余活性污泥完全资源化利用微生物集成技术

剩余活性污泥完全资源化利用微生物集成技术包括: 使用土著PHA合成菌回注法驯化并发酵活性污泥, 生产生物降解材料聚羟基脂肪酸酯(PHA); 采用土著嗜酸性氧化亚铁硫杆菌和氧化硫硫杆菌进行生物淋滤, 去除重金属; 以解磷菌和解钾菌为菌种, 进行固态发酵, 生产生物菌肥。结果表明, 500 L中试PHA占挥发性悬浮固体的20%以上; 重金属含量达到国家排放要求; 生物菌肥中活菌数大于1×108 个/g以上。实现了剩余活性污泥的近零排放。     

氧化硫硫杆菌和氧化亚铁硫杆菌的混合培养及其在MFC生物浸出中的应用初探

通过向9K培养基中添加单质硫和Fe SO_4·7H_2O两种能源物质,从好氧膜生物反应器(Membrane Bio-Reactor,MBR)污泥中分离富集氧化硫硫杆菌(Thiobacillus thiooxidans,T.t)和氧化亚铁硫杆菌(Thiobacillus ferrooxidans,T.f)的混合母液。采用以磁黄铁矿为能源物质的培养基对富集微生物进一步驯化培养后,将其接种在双室微生物燃料电池(Microbial Fuel Cell,MFC)反应器阳极室进行生物浸矿,从反应器产电和电化学分析两方面探究其运行性能。结果表明,富集微生物在磁黄铁矿培养基中培养18 d后,菌液中p H降低至0.98±0.01,Fe~(3+)、SO_4~(2-)浓度分别达到(138.6±10.06)mmol/L、(133.26±2.28)mmol/L;MFC反应器峰值电压达到(126.67±7.02)m V,最大功率密度75.88 m W/m~2。     

Effects of different sewage sludge applications on heavy metal accumulation,growth and yield of spinach (Spinacia oleracea L.)

In this study, we present the response of spinach to different amendment rates of sewage sludge (0, 10, 20, 30, 40 and 50 g kg^?1) in a greenhouse pot experiment, where plant growth, biomass and heavy metal uptake were measured. The results showed that sewage sludge application increased soil electric conductivity (EC), organic matter, chromium and zinc concentrations and decreased soil pH. All heavy metal concentrations of the sewage sludge were below the permissible limits for land application of sewage sludge recommended by the Council of the European Communities. Biomass and all growth parameters (except the shoot/root ratio) of spinach showed a positive response to sewage sludge applications up to 40 g kg^?1 compared to the control soil. Increasing the sewage sludge amendment rate caused an increase in all heavy metal concentrations (except lead) in spinach root and shoot. However, all heavy metal concentrations (except chromium and iron) were in the normal range and did not reach the phytotoxic levels. The spinach was characterized by a bioaccumulation factor <1.0 for all heavy metals. The translocation factor (TF) varied among the heavy metals as well as among the sewage sludge amendment rates. Spinach translocation mechanisms clearly restricted heavy metal transport to the edible parts (shoot) because the TFs for all heavy metals (except zinc) were <1.0. In conclusion, sewage sludge used in the present study can be considered for use as a fertilizer in spinach production systems in Saudi Arabia, and the results can serve as a management method for sewage sludge.     

城市污泥农用对植物-土壤系统的影响

城市污泥的合理处置是目前资源与环境科学研究领域中的重要课题之一.城市污泥因富含大量的有机质和有效营养成分,对农业土壤肥力、土壤物理结构和农业生产均有一定的积极促进作用,使得污泥农用成为可能.但城市污泥中含有的重金属、有机污染物等有害物质尤其是重金属,成为污泥农用处置的瓶颈.为提高我国城市污泥的农业资源化利用效率和减少污染物造成的负面效应,本文就国内外施用城市污泥对植物-土壤互作系统的影响及过程进行了综述,为进一步提高污泥利用效率提供理论依据和科学指导.     

Heavy Metal Phytotoxicity to Radish (Raphanus sativus L.) in a Digested Sludge-amended Gangetic Alluvium

A limiting factor in land application of sewage sludge is the resultant heavy metal accumulation in soils followed by biomagnification in the food chain, posing a potential hazard to animal and human health. In view of this fact, pot experiments were conducted to evaluate the effect of digested sludge application to soil on phytotoxicity of heavy metals such as Cd, Cr, Ni, and Pb to radish (Raphanus sativus L.) plants. Increasing sludge levels resulted in increased levels of DTPA-extractable heavy metals in the soil. Cadmium was the dominant metal extracted by DTPA followed by Ni, Pb, and Cr. The extractability of metals by DTPA tended to decrease from the first to the second crop. Dry matter yield of radish increased significantly as a function of increasing sludge treatments. Soil application of sludge raised the concentration of one or more heavy metals in plants. Shoots contained higher concentrations of Cd, Cr, and Ni than the roots of radish plants. Shoot concentrations of Cd, Cr, Ni, and Pb were within the tolerance levels of this crop at all rates of sludge application. Shoot as well as root concentration of Cd was above 0.5 mg kg^?1, considered toxic for human and animal consumption. The levels of DTPA-extractable Cd and Ni were less correlated while those of Cr and Pb were more correlated with their respective shoot and root contents. The results emphasize that accumulation of potentially toxic heavy metals in soil and their build-up in vegetable crops should not be ignored when sludge is applied as an amendment to land.     

污水污泥土地投放重金属的环境效应研究进展

本文综述了污水污泥土地投放中重金属的环境效应研究方面的进展,重点就污水污泥土地投放中对植物生长的影响、对土壤微生物、土壤酶及昆虫生长的影响、重金属向地下水中的迁移情况、重金属在土壤中的生物活性变化及其影响因素、污水污泥土地投放后重金属的长期变化及土壤修复剂对重金属毒性的控制等方面的研究进展进行综述。     

Phytoextraction of heavy metals from municipal sewage sludge by Rosa multiflora and Sida hermaphrodita

The aim of the study was to evaluate the efficacy of the multiflora rose var. “Jatar” (Rosa multiflora Thunb. ex Murray) and the Virginia fanpetals (Sida hermaphrodita Rusby) to phytoextract heavy metals from municipal sewage sludge. The 6-year field experiment involved four levels of fertilization with sewage sludge at doses of 0, 10, 20, 40, and 60 Mg DM (Dry Mass) sludge ha^?1. The increasing doses of sewage sludge were found to significantly increase the yield of multiflora rose and Virginia fanpetals biomass. They also significantly increased the content of heavy metals in these plants. The highest uptake of heavy metals by the multiflora rose and Virginia fanpetals crops was recorded at the fertilization dose of 60 Mg DM ? ha^?1. Our investigations show that the Virginia fanpetals was more efficient in the phytoextraction of Cr, Ni, Cu, Zn, and Cd from the sewage sludge than the multiflora rose, due to the greater yields and higher heavy metal uptake by the former plant. In turn, the multiflora rose phytoextracted greater amounts of Pb from the sewage sludge. The analyses indicate that the Virginia fanpetals can be used for phytoremediation (phytoextraction) of heavy metals contained in sewage sludge.     

构树的污泥适应性及养分和重金属吸收累积特征

构树是我国重要速生经济树种,具有适应性强、生物量大和重金属富集能力强等优点,而污泥中含有大量养分和重金属,在污泥中种植构树有望同时实现污泥生态修复和构树资源生产。本研究通过盆栽试验,分析在对照(赤红壤)、50%污泥(污泥、赤红壤混合基质,重量比各50%)和100%污泥基质中构树生长及不同部位(根、茎、叶)养分和重金属吸收累积特征,并通过主成分分析和隶属度函数对吸收累积能力进行综合评价。结果表明: 构树在50%和100%污泥中均可正常生长且株高、生物量显著高于对照,在100%污泥中长势最好,质量指数(1.02)分别是对照和50%污泥处理的4.3和2.4倍。50%和100%污泥处理构树各部位N含量和茎P含量显著高于对照,100%污泥处理构树茎、叶K含量显著低于对照。构树对Cu、Zn、Pb、Cd、Ni的吸收部位以根为主,根系重金属含量与污泥比例呈正相关,叶Pb、Cd含量符合《饲料卫生标准》(GB 13078—2017)。构树对Cd的吸收累积效果好于其他重金属元素。与对照相比,50%和100%污泥处理构树根部Zn、Pb、Cd滞留率显著提高(57.8%~85.8%),100%污泥处理构树根部Cu、Ni滞留率显著提高(67.5%和74.8%)。污泥处理全株养分和重金属累积量均显著大于对照,其中100%污泥处理显著大于50%污泥处理。与50%污泥处理相比,100%污泥处理构树各部位及全株养分和重金属累积量大幅提高。不同处理下构树污泥适应性和元素吸收累积的综合评价得分为100%污泥(0.848)>50%污泥(0.344)>对照(0.080)。构树对污泥具有良好的适应性,在纯污泥中能够正常生长并具有较强的吸收累积养分和重金属能力,可在修复污泥的同时进行构树资源生产。     

城市污泥土地利用研究

通过培养试验、盆栽试验和田间试验系统地研究了污泥的组分特征、性质及其农地和城市园林绿化地利用对作物或绿化灌木、土壤肥力及其环境的影响,结果表明,污泥富含有机质和氮磷养分,且养分当季有效性介于化肥农家肥之间。施用污泥将明显提高土壤肥力,表现改善土壤物理性质;增加土壤肥机质和氮磷水平,并增加土壤生物活性,因此施用污泥的处理作物产量较高,并有利于后茬作物的稳健生长。但污泥施用也存在重金属、病原物等污染     

施用污泥对小白菜生长及其迁转重金属的影响

采用盆栽方式,以厦门市筼筜污水处理厂的污泥作为有机肥种植小白菜,探讨污泥施用对小白菜生长和产量的影响及重金属在小白菜-土壤间的迁移转化和积累情况.结果表明:污泥中氮、磷、钾和有机质含量丰富,重金属含量均低于国家农用污泥中污染物控制标准;适宜的污泥施用量可促进小白菜的生长,污泥用量为5%时,小白菜长势最好,生物量最大;污...     

两种污泥连续施用对潮土重金属含量及酶活性的影响

采用盆栽土培试验,研究了工业污泥(化工厂底泥)及城市污水处理厂剩余污泥中重金属存在的形态与含量,以及两种污泥连续施用对潮土重金属含量及酶活性的影响。结果表明,两种污泥中的重金属主要是以非交换态存在,城市污水处理厂剩余污泥中总的重金属含量比工业污泥低,而重金属的有效性比工业污泥高;污泥的施用能增加潮土中脲酶的活性,多酚氧化酶及中性磷酸酶的活性与污泥的施用量有一定相关性,并与土壤中交换态Zn、Cu含量呈一定负相关,土壤多酚氧化酶及过氧化氢酶活性可作为土壤中重金属Zn污染的指示指标;污泥的施用有提高潮土中交换态Cu、Zn及Pb含量的趋势。     

Effects of Municipal Sewage Sludge Doses on the Chlorophyll Contents and Heavy Metal Concentration of Sugar Beet (Beta vulgaris var. saccharifera)

The present study was conducted to assess the suitability of sewage sludge amendment (SSA) in soil for Beta vulgaris var. saccharifera (sugar beet) by evaluating the heavy metal accumulation and physiological responses of plants grown at a 10%, 25%, and 50% sewage sludge amendment rate. The sewage sludge amendment was modified by the physicochemical properties of soil, thus increasing the availability of heavy metals in the soil and consequently increasing accumulation in plant parts. Cd, Pb, Ni, and Cu concentrations in roots were significantly higher in plants grown at 25% as compared to 50% SSA; however, Cr and Zn concentration was higher at 50% than 25% SSA. The concentrations of heavy metal showed a trend of Zn > Ni > Cu > Cr > Pb > Cd in roots and Zn > Cu > Ni > Cr > Pb > Cd in leaves. The only instance in which the chlorophyll content did not increase after the sewage sludge treatments was 50%. There were approximately 1.12-fold differences between the control and 50% sewage sludge application for chlorophyll content. The sewage sludge amendment led to a significant increase in Pb, Cr, Cd, Cu, Zn, and Ni concentrations of the soil. The heavy metal accumulation in the soil after the treatments did not exceed the limits for the land application of sewage sludge recommended by the US Environmental Protection Agency (US EPA). The increased concentration of heavy metals in the soil due to the sewage sludge amendment led to increases in heavy metal uptake and the leaf and root concentrations of Ni, Zn, Cd, Cu, Cr, Pb, and Zn in plants as compared to those grown on unamended soil. More accumulation occurred in roots and leaves than in shoots for most of the heavy metals. The concentrations of Cd, Cr, and Pb were more than the permissible limits of national standards in the edible portion of sugar beet grown on different sewage sludge amendment ratios. The study concludes that the sewage sludge amendment in the soil for growing sugar beet may not be a good option due to risk of contamination of Cr, Pb, and Cd.