Procéadéa de solubilisation biologique des méataux dans les boues anaéarobies d'éapuration: Filtrabilitéa,neutralisation et teneurs en n et p des boues traitéaes

Biological solubilization of heavy metals in anaerobic sewage sludge was performed in a continuous reactor with two mean hydraulic residence times (0.5, 0.75 day). Following filtration of the processed sludge, the amount of solubilized Cu and Zn decreased from 92% and 94% to 78% and 77% respectively in the sludge. Most iron reprecipitates in filtered sludge. Processed sludge is easy to deshydrate. The filtrability index (r_0.5) of processed sludge is 38 times smaller than anaerobic sludge, without adding polymers. It was found that the values obtained for r_0.5 and inferior to 8 × 10¹² m/kg enable the sludge to be dehydrated in a plate filter press without adding polymers. Centrifugation can also be used. The content in nitrogen, phosphorus and hydrolysable phosphorus remain unchanged during processing. 47% of the ammonia is lost in the filtrate. The neutralization of processed sludge (pH = 7) and contaminated supernatant (pH = 10) require a small quantity of base. The selective precipitation of metals could allow the recovery of Cu in the generated metallic sludge. Finally, results show the preliminary feasability of the process. A pilot scale study could enable the scale-up of the process.     

Mechanism of bioleaching chalcopyrite by Acidithiobacillus ferrooxidans in agar-simulated extracellular polymeric substances media

The mechanism of leaching chalcopyrite by Acidithiobacillus ferrooxidans (A. ferrooxidans) in agar-simulated extracellular polymeric substances (EPS) media was investigated. The results indicate that bacterial EPS can release H+ and concentrate Fe3+; Fe2+ is movable between agar-simulated EPS phase and bulk solution phase, but it is difficult for Fe3+ to move due to its hydroxylation and EPS complex action; A. ferrooxidans first prefer Fe2+ as energy to metabolize compared with chalcopyrite, and a suitable ...     

脱氮硫杆菌的生态特性及其应用

介绍了脱氮硫杆菌的生态特性与适宜的生长条件。说明了脱氮硫杆菌在地球元素循环中的地位与作用。向浅层油藏中添加硝酸盐和磷酸盐，能够刺激其中的脱氮硫杆菌大量增殖，抑制H2S的生成，消除FeS造成的堵塞，减轻管材的腐蚀。以硫磺为电子供体，石灰石作碳源和平衡碱度，脱氮硫杆菌接种的反应器用来脱除饮用水和地下水中的硝酸盐，可获得98％以上的脱除率，但易引起SO4^2-和硬度超标，若将其与其它反硝化方法集成使用则可克服这一缺陷。用脱氮硫杆菌在碱性条件下脱除天然气中的H2S亦能获得良好的效果。     

高铁浓度下氧化亚铁硫杆菌的生长动力学

通过改变初始Fe2 浓度,对氧化亚铁硫杆菌生长过程中的代谢变化进行了研究。依据产物抑制的Monod方程,推导并建立了氧化亚铁硫杆菌在高铁浓度下的生长动力学方程。实验结果表明:随着Fe2 浓度的增加,底物抑制作用增加,导致细菌对底物的亲和力减小,Ks值增大。细菌比生长速率的实验值和模拟值之间的相关系数为0.97,表明该动力学方程能够较好地描述高铁浓度下氧化亚铁硫杆菌的生长情况。     

煤炭微生物脱硫的研究

经对能源条件、细菌接种量、氮素营奍、煤粉粒度、煤浆浓度和酸预浸洗煤样等影响煤炭微生物脱硫的因素进行研究,确定了最佳条件。在12天浸出时间内,煤炭总硫脱除率可达53.0%。     

一株浸矿细菌的分离及其对低品位硫化镍铜矿中镍的浸出

从云南某铜矿井下酸性污水中分离到嗜酸菌株ynxd-1,对其形态、生长特性、16 S rRNA基因序列及其对低品位硫化镍铜矿的摇瓶浸出效果进行了研究.结果表明:细菌细胞呈短杆状,革兰氏染色阴性,不产芽孢,最适pH值及生长温度分别为2.0和30℃.菌株ynxd-1在10%(W/V)矿浆浓度及30℃温度的条件下摇瓶培养浸出28 d,低品位硫化镍铜矿镍的浸出率为56.4%.16 S rRNA基因序列分析表明,菌株ynxd-1与嗜酸氧化亚铁硫杆菌的同源性达到99%,可以鉴定为嗜酸氧化亚铁硫杆菌菌株.     

Volume of extracellular polymeric substance coverage of individual Acidithiobacillus ferrooxidans bacterium measured by atomic force microscopy

The Acidithiobacillus ferrooxidans response to stress associated with the drying process is known to be the production of extracellular polymeric substance (EPS) coverage. Here, samples of A. ferrooxidans suspensions grown in 1.8 pH and 3.0 pH and dried on mica and silicon are shown to form a structure of isolated bacteria. Individual bacteria coverage patterns were imaged by atomic force microscopy (AFM) on hydrophobic (silicon) and hydrophilic (mica) substrates. A comparison of images of covered and uncovered bacteria establish the volume of individual EPS coverage. The EPS production for bacteria on hydrophobic substrates shows a substantial decrease (a factor of 30) in the EPS volume per bacterium when compared with the one on hydrophilic substrates. Shape and volume determination of EPS structures on bacteria as a function of hydrophobicity or hydrophilicity of the substrate may help to determine the functions of EPS on bacterial aggregates.     

脱硫菌培养条件及脱硫研究

介绍了pH值、培养时间和接种量对氧化亚铁硫杆菌生长的影响。测定该菌对煤炭脱硫效果的结果表明，在9K培养基初始pH=2、接种量15%的情况下，氧化亚铁硫杆菌生长5 d后浓度达108个/mL，10 d后黄铁矿脱除率达到52.29%,全硫脱除率达到37.75%。     

硫化叶菌对镍钼硫化矿的浸出作用

对金属硫叶菌浸出镍钼硫化矿进行了研究. 结果表明,有菌组镍的浸出率均在90%以上,而无菌组为77.64%;驯化菌比非驯化菌的浸出率高,前者镍和钼的浸出率分别为94.7%和70.2%,后者为93.1%和68.4%;pH为2时浸出效果最佳,镍浸出率达100%,钼浸出率为66.97%;粒径<0.048 mm和<0.077 mm的浸样镍浸出率均达到100%,钼浸出率分别为68.4%和64.5%;低矿浆浓度比高矿浆浓度的浸出率高,5 g/L矿浆镍和钼的浸出率分别达100%和87.29%;在无菌条件下,浸样添加0.5 g/L Fe3+和对照组的镍浸出率分别为92.8%和76.6%,钼浸出率为52.56%和49.34%;嗜热菌(金属硫叶菌)比常温菌(氧化亚铁硫杆菌)的浸出率高,前者镍钼浸出率分别为93.17%和73.52%,后者为67.34%和38.36%.