硫酸盐还原菌的生长因子的探讨

对厌氧处理硫酸盐废水过程中硫酸盐还原菌的生态学进行了综述,详细介绍了硫酸盐还原菌的生理特性、所利用的碳源、氮源的种类,以及影响SRB对废水中硫酸根还原作用的多种因子,如pH值、温度、氧化还原电位等各种因素,并阐明硫酸盐还原菌是一类多样性群体,对硫酸盐废水处理有重要的意义。     

单质铁强化生物还原法处理硫酸盐废水

为提高生物法处理酸性硫酸盐废水的效果,采用间歇试验对生物还原体系的特性进行了研究,重点考察了加入单质铁(Fe0)对硫酸盐还原反应的强化作用.结果表明,pH＞6.5的中性偏酸环境最适合硫酸盐还原菌(SRB)的生长代谢,降低pH值会抑制反应的进行,且初始pH值越低则抑制作用越强.Fe0对硫酸盐还原过程有强化作用,可使体系承受更大的酸性负荷,并明显缩短了反应延迟期,但是对硫酸盐的还原反应速度、最终去除量和还原率几乎没有影响.废水pH值随着硫酸盐还原反应的进行而提高,经过SRB处理后最终可达7.0以上.加入Fe0的体系进行硫酸盐还原反应所消耗的COD较少,△COD/△SO2-4 为0.91～0.98.     

硫酸盐还原菌处理高浓硫酸盐废水

采用硫酸盐还原菌(SRB)在厌氧序批式反应器(ASBR)中处理高浓度硫酸盐废水。对钛白粉生产废水的试验显示，SO4^2-的去除率可达到83．5％，达到了国家排放标准(250mg／L)。COD／SO4^2-值对SO4^2-的去除率有较大影响，比值为2～3时去除效果最佳。在试验装置的设计中采用了气循环与水循环并用的方法，以防止H2S气体对SRB的毒害并起到搅拌作用。     

连续流完全混合生物膜法处理硫酸盐废水

采用连续流搅拌槽式反应器(CSTR)处理硫酸盐废水,20d反应器即启动成功。研究结果表明,不调节进水碱度时反应系统可在pH值为5.4～5.7内运行,但抗酸度冲击能力较差;调节进水碱度时系统可在pH值为6.2～6.9间稳定运行,抗酸度冲击能力较强。COD/SO2-4>2.7时反应系统属于电子受体限制型体系,COD/SO2-4<2.7时属于电子供体限制型体系,增加电子受体限制型系统中的硫酸盐浓度和增加电子供体限制型系统中的COD浓度都可提高系统的还原效能。当HRT>5.2h时,硫酸盐还原菌(SRB)可充分利用酸化产生的乙醇。在保证硫酸根去除率≥80%时,SO2-4/(m3·d)。4负荷最高可达7.58kgSO2-     

ABR处理高浓度硫酸盐有机废水的性能

以人工配制的高浓度硫酸盐有机废水作为原水，研究了厌氧折流板反应器（ABR）处理高浓度硫酸盐有机废水的性能。结果表明，在温度为（33．2±0．1）℃、HRT为20～24h以及进水COD、硫酸盐浓度分别为5000和300～1500mg／L的条件下，ABR处理高浓度硫酸盐有机废水的效果较好，对COD的去除率可达90％以上，SO4^2-的还原率稳定在96％。COD／SO4^2-值是影响SRB与MPB竞争关系的重要指标，对COD去除率和SO4^2-还原率都有很大的影响。启动方式对厌氧反应器处理含硫酸盐废水的性能有很大的影响，低硫酸盐负荷启动方式会使MPB取得初始相对优势，SO4^2-还原对厌氧处理过程影响较小。     

UASB/曝气沉淀/IC反应器处理高浓度硫酸盐有机废水

在赤霉素生产过程中产生的高浓度硫酸盐有机废水,处理难度较大。采用UASB／曝气沉影IC反应器工艺处理该废水,UASB中的硫酸盐还原菌将硫酸根还原为硫化物,曝气池中的脱硫杆菌则将硫化物氧化为单质硫,并在沉淀池中去除,IC反应器去除COD。系统稳定运行后,对硫酸盐的去除率〉90％,对COD的去除率〉80％。     

油气田硫酸盐还原菌控制技术应用探讨

在油气田开采、集输和气田水回注系统中,存在着各种微生物群体,包括硫酸盐还原菌、铁细菌以及其他微生物。其中,危害性最大的微生物就是硫酸盐还原菌(SRB)。通过对重庆气矿目前站场SRB分布统计分析,结合站场气田水处理工艺及油套管腐蚀状况,经分析对比现有多种生物腐蚀控制技术,推荐LEMUPZ-H物理法杀菌技术。现场应用表明,该工艺能有效杀灭和抑制气田水中SRB,对站场排污、气田水转输及回注系统均能起到较好的保护作用,是一种经济有效的应对SRB腐蚀的控制保护措施。     

塔中油田硫酸盐还原菌恶性繁殖机理分析＊

硫酸盐还原菌等的恶性繁殖使油田生产管线设施腐蚀破坏、结垢堵塞,注入地层后对油层造成伤害。研究发现,塔中油田联合站水体可检测SRB菌数高达2.5×104个/mL,注水管垢含FeS高达29.8％,属硫酸盐还原菌恶性繁殖代谢产物。塔中油田水系统各主要环节中硫酸盐还原菌和硫化氢含量与油田水处理工艺特点密切相关,其中塔中油田联合站完全密闭的水处理压力流程是造成该站硫酸盐还原菌恶性繁殖的主要原因。实验表明,前端适度曝氧、添加H2O2等氧化性杀菌剂和300 mg/L冲击式加药等都是抑制硫酸盐还原菌的有效方法。     

生物膜氨氧化及对硫酸盐还原的影响

利用好氧生物转盘进行了生物膜脱氨的试验,测定了生物膜内硫酸盐还原与硝酸盐还原及DO之间的关系。结果表明:在进水NH4 -N为40 mg/L、HRT为5.49 h时,氨氧化率>85%;采用分段进水,合理利用碳源,有利于自养菌繁殖,从而促进硝化作用;由于受水力冲刷等作用的影响,在生物膜内DO扩散深度可达350μm左右(大于在污泥基团的扩散深度),只有在低DO的层面上才出现NO3--N的反硝化;在含有NO3--N的系统内,生物膜内硫酸盐还原作用减弱,表明硫酸盐还原与反硝化是相互影响的,这一结果对富含硫酸盐的有机废水生物脱氮处理有一定的参考价值。     

温度对硫酸盐还原菌(SRB)处理煤矿废水实验研究

基于SRB法处理煤矿酸性废水成本低,无二次污染的事实,通过采用实验室静态模拟的方法考察了不同温度对硫酸盐还原菌处理煤矿酸性废水的效果,以期有效治理采煤废水污染,保护生态环境。     

Long term competition between sulfate-reducing and methane-producing bacteria for acetate in anaerobic biofilm

A long term competition between sulfate-reducing bacteria (SRB) and methane-producing bacteria (MPB) for acetate was investigated using a laboratory scale anaerobic fluidized bed. When the synthetic wastewater composed of acetate and sulfate was fed at a low organic loading rate, averages of the remaining acetate and sulfate concentrations were 1.7 mg Cl⁻¹ and 78.5 mg l⁻¹, respectively. During several months of this acetate limited operation the methane production rate as well as the microbial mass of MPB declined gradually, whereas the amount of reduced sulfate along with the microbial mass of SRB increased, which apparently indicates that SRB out-compete MPB in the biofilm at lower acetate concentrations. On the other hand, MPB were able to form a biofilm faster than SRB at higher acetate concentrations presumably due to MPB's higher ability to adhere carrier surfaces compared with SRB. Kinetic constants for both species in the biofilm were determined and compared with those reported for pure MPB and SRB cultures. Based on the kinetic mechanism of this competition, operational conditions which would support methanogenesis by suppressing sulfate reduction were identified.     

High rate sulfate reduction at pH 6 in a pH-auxostat submerged membrane bioreactor fed with formate

Many industrial waste and process waters contain high concentrations of sulfate, which can be removed by sulfate-reducing bacteria (SRB). This paper reports on mesophilic (30 degrees C) sulfate reduction at pH 6 with formate as electron donor in a membrane bioreactor with a pH-auxostat dosing system. A mixed microbial community from full-scale industrial wastewater treatment bioreactors operated at pH 7 was used as inoculum. The pH-auxostat enabled the bacteria to convert sulfate at a volumetric activity of 302 mmol sulfate reduced per liter per day and a specific activity of 110 mmol sulfate reduced per gram volatile suspended solids per day. Biomass grew in 15 days from 0.2 to 4 g volatile suspended solids per liter. This study shows that it is possible to reduce sulfate at pH 6 with formate as electron donor at a high volumetric and specific activity with inocula from full-scale industrial wastewater treatment bioreactors operated at neutral pH. The combination of a membrane bioreactor and a pH-auxostat is a useful research tool to study processes with unknown growth rates at maximum activities.     

Impact of nitrate addition on biofilm properties and activities in rising main sewers

Anaerobic sewer biofilm is a composite of many different microbial populations, including sulfate reducing bacteria (SRB), methanogens and heterotrophic bacteria. Nitrate addition to sewers in an attempt to control hydrogen sulfide concentrations affects the behaviour of these populations, which in turn impacts on wastewater characteristics. Experiments were carried out on a laboratory reactor system simulating a rising main to determine the impact of nitrate addition on the microbial activities of anaerobic sewer biofilm. Nitrate was added to the start of the rising main during sewage pump cycles at a concentration of 30 mg-N L⁻¹ for over 5 months. While it reduced sulfide levels at the outlet of the system by 66%, nitrate was not toxic or inhibitory to SRB activity and did not affect the dominant SRB populations in the biofilm. Long-term nitrate addition in fact stimulated additional SRB activity in downstream biofilm. Nitrate addition also stimulated the activity of nitrate reducing, sulfide oxidizing bacteria that appeared to be primarily responsible for the prevention of sulfide build up in the wastewater in the presence of nitrate. A short adaptation period of three to four nitrate exposure events (approximately 10 h) was required to stimulate biological sulfide oxidation, beyond which no sulfide accumulation was observed under anoxic conditions. Nitrate addition effectively controlled methane concentrations in the wastewater. The nitrate uptake rate of the biofilm increased with repeated exposure to nitrate, which in turn increased the consumption of biodegradable COD in the wastewater. These results provide a comprehensive understanding of the impact of nitrate addition on wastewater composition and sewer biofilm microbial activities, which will facilitate optimization of nitrate dosing for effective sulfide control in rising main sewers.     

Sulfidogenic fluidized-bed treatment of metal-containing wastewater at 8 and 65 degrees C temperatures is limited by acetate oxidation

Acetate utilization in sulfidogenic fluidized-bed reactors (FBRs) was investigated for the treatment of iron containing wastewater at low (8 degrees C) and high (65 degrees C) temperatures. The FBRs operated at low and high temperatures were inoculated with cultures of sulfate-reducing bacteria (SRB) originally enriched from arctic and hot mining environments, respectively. Acetate was not utilized as a carbon and electron source for SRB at 8 degrees C. With ethanol, hydrogen sulfide was produced from ethanol to acetate oxidation, which precipitated the iron. Then, several attempts were made to obtain acetate oxidation at 8 degrees C. Inoculation of two different low temperature enrichments and operating the FBR for a long period of time (321 days) did not result in enrichment of acetate oxidizing SRB. Due to the absence of acetate oxidation at 8 degrees C, external alkalinity addition was required to keep the pH neutral. At 65 degrees C, average acetate and sulfate removals were 52+/-12% and 24+/-8% at 670 mg/Ld acetate and 1500 mg/Ld sulfate loadings, respectively. The produced alkalinity from acetate oxidation increased the pH from 6.4 to around 7.5 and electron flow to sulfate reduction averaged 65%. Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA genes showed quite stable SRB community at 8 degrees C, whereas, at 65 degrees C SRB community was dynamic. In the FBRs, Desulfomicrobium apsheronum and Desulfosporosinus sp. at 8 degrees C and Desulfotomaculum sp. at 65 degrees C were detected.     

ABR处理糖蜜酒精模拟废水的启动试验

为避免糖蜜酒精废水厌氧处理中硫酸盐还原菌(SRB)对产甲烷菌(MPB)的基质竞争性抑制,并消除硫化物对MPB的毒性作用,在30℃下,利用厌氧折流板反应器(ABR)对糖蜜酒精模拟废水进行了历时92d的启动试验。结果表明,采用低COD和低SO42-负荷启动,是ABR反应器成功启动的关键;成功启动后,各隔室出现明显的相分离(产酸还原硫酸盐相和生成硫单质产甲烷相)特征,说明在微氧/厌氧环境中,酸化菌(AB)可与SRB共存,无色硫细菌(CSB)可与MPB共存;在反应器的第4隔室生成大量单质硫颗粒,可以达到回收利用单质硫的目的。可见,采用ABR处理糖蜜酒精废水是完全可行的。     

Evaluation of oxygen injection as a means of controlling sulfide production in a sewer system

Oxygen injection is often used to control biogenic production of hydrogen sulfide in sewers. Experiments were carried out on a laboratory system mimicking a rising main to investigate the impact of oxygen injection on anaerobic sewer biofilm activities. Oxygen injection (15-25 mg O₂/L per pump event) to the inlet of the system decreased the overall sulfide discharge levels by 65%. Oxygen was an effective chemical and biological oxidant of sulfide but did not cause a cessation in sulfide production, which continued in the deeper layers of the biofilm irrespective of the oxygen concentration in the bulk. Sulfide accumulation resumed instantaneously on depletion of the oxygen. Oxygen did not exhibit any toxic effect on sulfate reducing bacteria (SRB) in the biofilm. It further stimulated SRB growth and increased SRB activity in downstream biofilms due to increased availability of sulfate at these locations as the result of oxic conditions upstream. The oxygen uptake rate of the system increased with repeated exposure to oxygen, with concomitant consumption of organic carbon in the wastewater. These results suggest that optimization of oxygen injection is necessary for maximum effectiveness in controlling sulfide concentrations in sewers.     

Nitrate stimulation of indigenous nitrate-reducing, sulfide-oxidising bacterial community in wastewater anaerobic biofilms

The role of the nitrate-reducing, sulfide-oxidising bacteria (NR-SOB) in the nitrate-mediated inhibition of sulfide net production by anaerobic wastewater biofilms was analyzed in two experimental bioreactors, continuously fed with the primary effluent of a wastewater treatment plant, one used as control (BRC) and the other one supplemented with nitrate (BRN). This study integrated information from H(2)S and pH microelectrodes, RNA-based molecular techniques, and the time course of biofilm growth and bioreactors water phase. Biofilms were a net source of sulfide for the water phase (2.01 micromol S(2-)(tot)m(-2)s(-1)) in the absence of nitrate dosing. Nitrate addition effectively led to the cessation of sulfide release from biofilms despite which a low rate of net sulfate reduction activity (0.26 micromol S(2-)(tot)m(-2)s(-1)) persisted at a deep layer within the biofilm. Indigenous NR-SOB including Thiomicrospira denitrificans, Arcobacter sp., and Thiobacillus denitrificans were stimulated by nitrate addition resulting in the elimination of most sulfide from the biofilms. Active sulfate reducing bacteria (SRB) represented comparable fractions of total metabolically active bacteria in the libraries obtained from BRN and BRC. However, we detected changes in the taxonomic composition of the SRB community suggesting its adaptation to a higher level of NR-SOB activity in the presence of nitrate.     

Microbial sulfate reduction under sequentially acidic conditions in an upflow anaerobic packed bed bioreactor

The aim of this study was to operate an upflow anaerobic packed bed reactor (UAPB) containing sulfate reducing bacteria (SRB) under acidic conditions similar to those found in acid mine drainage (AMD). The UAPB was filled with sand and operated under continuous flow at progressively lower pH and was shown to be capable of supporting sulfate reduction at pH values of 6.0, 5.0, 4.5, 4.0 and 3.5 in a synthetic medium containing 53.5 mmol l(-1) lactate. Sulfate reduction rates of 553-1,052 mmol m(-3) d(-1) were obtained when the influent solution pH was progressively lowered from pH 6.0 to 4.0, under an optimal flow rate of 2.61 ml min(-1). When the influent pH was further lowered to pH 3.5, sulfate reduction was substantially reduced with only about 1% sulfate removed at a rate of 3.35 mmol m(-3) d(-1) after 20 days of operation. However, viable SRB were recovered from the column, indicating that the SRB population was capable of surviving and metabolizing at low levels even at pH 3.5 conditions for at least 20 days. The changes in conductivity in the SRB column did not always occur with changes in pH and redox potential, suggesting that conductivity measurements may be more sensitive to SRB activity and could be used as an additional tool for monitoring SRB activity. The bioreactor containing SRB was able to reduce sulfate and generate alkalinity even when challenged with influent as low as pH 3.5, indicating that such treatment systems have potential for bioremediating highly acidic, sulfate contaminated waste waters.