白腐真菌处理灰法造纸黑液废水的研究

研究了不同白腐真菌菌株对灰法造黑液废水的处理,考察了黑液废水浓度和碳氮源添加量对黑液脱色及COD去除率的影响。研究表明,变色栓菌（Trametes verscolor)对黑液废水的处理效果最好,其COD去除率为64．25％,脱色率为47．31％,用自选的白腐真菌AH28－2菌株处理未经稀释的黑液废水,分别添加0．2％纤维二维糖和0．02％天冬酰胺,COD去除率达62．45％和68．60％,研究发现锰过氧化物酶（MnP)和木素过氧化物酶（LiP)对COD去除率有直接影响,MnP/LiP酶活力值越高,处理效果越好。     

人工湿地处理造纸废水后细菌群落结构变化

人工湿地通过模拟自然湿地的生态系统,能够实现污染物的去除,是一种高效经济的污水处理手段,但是对人工湿地处理后污水中细菌群落的研究较少。采集了造纸厂排污口和人工湿地出水口的水样,检测了溶解氧、pH值和盐度等水质指标,对主要污染物的含量进行了测定和分析,并利用DGGE技术对细菌群落的变化进行了研究。结果表明:(1)造纸污水经人工湿地处理后水质有明显提高;(2)人工湿地处理后细菌群落结构发生变化,优势菌由γ变形菌和衣原体变为α变形菌,而且微生物多样性指数Shannon-Wiener's降低;(3)人工湿地处理前污水中存在着大量致病微生物和降解微生物,处理后以环境友好的固氮菌和少量致病菌为主。研究结果揭示了人工湿地不仅可以去除造纸废水中的污染物,改善水质而且可以大大减少向环境中排放的致病微生物,防止由致病微生物引起的生态灾难的发生,为将来人工湿地应用于工业污水处理和微生物生态安全评估提供有效可靠的依据。     

EMBR技术处理工业园区综合废水试验研究

国内工业园区排放的综合废水中会产生复合污染且污染物具有多样性,致使目前常用的废水处理工艺难以达到国家废水处理的标准。本研究在膜生物反应器的基础上构建了电场-膜生物反应器,研究了电流密度和冲击负荷对COD_(cr)、氨氮和TN的影响。发现了电流密度对电场-膜生物反应器去除COD_(cr)效率没影响,而对TN去除率有很大的影响,冲击负荷对氨氮的去除效率没有影响。经过63 d连续运行,中试试验结果显示:电场-膜生物反应器的耦合对解决工业园区综合废水处理的难题有明显的效果,出水水质基本达到《城镇污水处理厂污染物排放标准》(GB18918-2002)的一级B标准。     

几种混凝剂用于处理制浆造纸综合废水的性能试验

利用烧杯混凝试验,通过改变pH值、药剂投加量等方法开展了一系列混凝试验,比较了一种新型聚合混凝剂硫酸铝聚合氯化铝对以木浆为主的制浆造纸厂的综合废水的处理效果.结果表明,在最佳pH值和投药量条件下,新型聚合混凝剂的处理效果最好.当pH为8.29,药剂投加量为175mg·L^-1时,即使不投加CPAM,处理后的废水COD_Cr去除率为87.4%,浊度去除率为96.4%,色度去除率为89.5%;出水COD_Cr和色度分别为90mg·L^-1左右和约32倍,均达到了广东省《水污染物排放限值》(DB4426-2001)第二时段的一级标准.     

微藻废水生物处理技术研究进展

微藻因生长速率快、细胞脂质含量高及具有生物隔离二氧化碳能力,已作为新一代生物质能源受到广泛关注.然而,投入大量淡水资源并需在生长期间持续提供营养物质已成为规模化培育微藻的主要障碍.将微藻培育系统与废水处理相结合是经济可行的污水资源化方案.基于微藻生长期间对氮磷等营养物质的利用机制,本文综述了微藻在各类废水生物处理过程中的应用情况,着重分析了其对废水中有机与无机化合物、重金属以及病原体的去除或抑制能力.同时,考察了废水初始营养物浓度、光照、温度、pH与盐度以及气体交换量等环境因素对微藻生长代谢的影响.此外,结合微藻规模化应用所面临的问题,对微藻废水处理技术的应用前景及发展方向进行了展望,旨在为水生态系统的建设与管理提供参考.     

味精废水综合处理的研究

提出了利用味精废水培养苏云金芽孢杆菌进而生产Bt生物农药的新的味精废水处理方法.对苏云金芽孢杆菌在味精废水中培养的培养基优化和深层培养条件及深层培养过程各参数的变化规律等进行了较为系统的研究,提出了进行工业化试验的培养工艺.     

水产养殖废水的危害及处理技术

目前,我国的水产养殖行业发展迅速,但养殖过程中缺乏科学的规范指导,因而会产生大量养殖废水。排放未经处理的水产养殖废水,不仅会破坏生态平衡,还会影响水产品的质量,甚至危害人们的生命健康。因此,为了解决水产养殖废水的问题,实现可持续发展,处理水产养殖废水的技术便应运而生。文章总结了物理法、生物法和物理化学法处理水产养殖废水的利弊,得知物理法和化学法具有成本花费高、再利用程度低等不足。生物法则具有周期短、危害小、花费少、可循环利用等优点,可为养殖户提供理论参考。     

生物垃圾处理过程中渗滤液混凝处理的实验研究

通过对混凝剂(PAS)用量、酸度、温度对垃圾处理过程中渗滤液混凝效果影响的研究,结果表明:用聚合硫酸铝进行混凝处理时,对渗滤液的氨氮处理效果不佳,对CODcr和浊度处理效果甚佳.根据三因素三水平的正交实验,得出处理过程中三个因素对CODcr去除率影响的主次关系为:pH＞聚合硫酸铝的用量＞温度.验证试验结果表明:混凝剂加入量15mL(10%)、pH为6.7、温度为50℃时为最优化工艺条件,CODcr去除率达到76.2%.     

电解法处理罗丹明B废水的研究

在阳极为Ti/RuO_2,阴极为泡沫镍,Na_2SO_4以及少量NaCl为电解质的条件下,对罗丹明B的电化学脱色效果进行了研究,探讨了外加电压、反应时间对罗丹明B脱色的影响。研究结果表明,电解含20 mg/L罗丹明B溶液,在Na_2SO_4浓度为0.1 mg/L、NaCl浓度为12 mg/300 mL的条件下,外加电压为8 V、降解40 min时电解效果最理想,高达99.2%。     

从源头防治制浆造纸废水污染的新策略

制浆造纸工业废水对环境造成了严重污染。本文概述了微生物生物技术在防治造纸污染中的应用,同时着重介绍了木质素生物合成途径与转基因植物降低造纸原料木质素含量的研究进展,对我国发展从源头防治制浆造纸污染的策略提出了建议     

Contact Angle Measurement and Cell Hydrophobicity of Granular Sludge from Upflow Anaerobic Sludge Bed Reactors

The contact angle, which is generally used to evaluate the hydrophobicities of pure bacterial strains and solid surfaces, was used to study mixed cell cultures of bacteria involved in anaerobic digestion. Previously published data and data from this study showed that most acidogens are hydrophilic (contact angle, <45(deg)) but most of the acetogens and methanogens isolated from granular sludge are hydrophobic (contact angle, >45(deg)). The hydrophobicities of mixtures of hydrophilic and hydrophobic cells were found to be linearly correlated with the cell mixing ratio. The hydrophobicities of cells present in effluents from upflow anaerobic sludge bed reactors which were treating different types of substrates were different depending on the reactor conditions. When the reactor liquid had a high surface tension, cells sloughing off from sludge granules, as well as cells present on the outer surfaces of the granules, were hydrophobic. Short-term batch enrichment cultures revealed that proteins selected for highly hydrophilic cells. Long-term in-reactor enrichment cultures revealed that sugars selected for hydrophilic acidogens on the surfaces of the granules, while fatty acids tended to enrich for hydrophobic methanogens. When linear alkylbenzenesulfonate was added, the cells on the surfaces of granules became more hydrophilic. Control tests performed with pure cultures revealed that there was no change in the surface properties due to linear alkylbenzenesulfonate; hence, the changes in the wash-out observed probably reflect changes in the species composition of the microbial association. A surface layer with moderate hydrophobicity, a middle layer with extremely high hydrophobicity, and a core with high hydrophobicity could be distinguished in the grey granules which we studied.     

Start-up criteria for a Upflow Anaerobic Sludge Blanket (UASB) reactor

A laboratory scale Upflow Anaerobic Sludge Blanket (UASB) reactor study was done with spentwash (distillery effluent) as substrate. The start-up studies revealed that the recirculation of biogas, produced during the initial stages, under low organic loading rates helps in mixing as well as partial supplementation of carbon dioxide for excess hydrogen in the reactor. The gas composition before and after recirculation, the volatile acids profile and the solids variation along the reactor height before and after recirculation were studied. The process efficiency and methane content increases substantially after recirculation of biogas and the microscopic examination of the sludge during the experiment indicates that the granules mainly composed of long multicellular filaments of rod shaped organisms, presumably methanothrix soehngenii.     

Microbial and Physicochemical Characteristics of Compact Anaerobic Ammonium-Oxidizing Granules in an Upflow Anaerobic Sludge Blanket Reactor

Anaerobic ammonium oxidation (anammox) is a promising new process to treat high-strength nitrogenous wastewater. Due to the low growth rate of anaerobic ammonium-oxidizing bacteria, efficient biomass retention is essential for reactor operation. Therefore, we studied the settling ability and community composition of the anaerobic ammonium-oxidizing granules, which were cultivated in an upflow anaerobic sludge blanket (UASB) reactor seeded with aerobic granules. With this seed, the start-up period was less than 160 days at a NH₄⁺-N removal efficiency of 94% and a loading rate of 0.064 kg N per kg volatile suspended solids per day. The formed granules were bright red and had a high settling velocity (41 to 79 m h⁻¹). Cells and extracellular polymeric substances were evenly distributed over the anaerobic ammonium-oxidizing granules. The high percentage of anaerobic ammonium-oxidizing bacteria in the granules could be visualized by fluorescent in situ hybridization and electron microscopy. The copy numbers of 16S rRNA genes of anaerobic ammonium-oxidizing bacteria in the granules were determined to be 4.6 × 10⁸ copies ml⁻¹. The results of this study could be used for a better design, shorter start-up time, and more stable operation of anammox systems for the treatment of nitrogen-rich wastewaters.The anaerobic ammonia oxidation (anammox) process is a recently discovered biological nitrogen removal technology in which ammonia is oxidized to nitrogen gas with nitrite as the electron acceptor (5, 29, 32). In contrast to heterotrophic denitrification (6, 26), the anammox process does not require external electron donors (e.g., methanol) due to their chemolithoautotrophic lifestyle. Furthermore, if this process is combined with a partial nitrification step, only half of the ammonium needs to be nitrified to nitrite, which together with the remaining ammonium can subsequently be converted into nitrogen through the anammox process. This reduces the oxygen demand of the system and leads to further reduction in operational costs (27).The anaerobic ammonium-oxidizing bacteria (anammox bacteria) have a low growth rate (18), with a doubling time at best estimated as 7 to 11 days (18, 28). The yield of the anammox bacteria has been determined to be 0.066 mol C biomass mol⁻¹ ammonium consumed, and the maximum ammonium consumption rate is ∼45 nmol mg⁻¹ protein min⁻¹ (18). Given the low growth rate and low yield, very efficient biomass retention is essential to retain the anammox bacteria within the reactor systems during cultivation (19). The enrichment of anammox bacteria from a mixed inoculum requires the optimization of conditions favorable for the anammox bacteria and generally takes 200 to 300 days (5, 6, 27). Thus, conditions that would reduce the start-up time of anammox reactors would positively effect the implementation of the process. Several sources of inocula, such as activated sludge (4), nitrifying activated sludge (27), and anaerobic sludge (6), have been used for the start-up of anammox reactors with start-up times of as long as 1,000 days (27).Aerobic granules have been reported to have high microbial diversity (31) and compact structure with very good settling properties resulting in an efficient means of biomass retention. These properties, including interspecies competition and mass transfer, result in the stratification of microbial species with anoxic pockets in the interior of the granules that may be suitable to harbor anammox bacteria. Therefore, the main objective of this study was to investigate the feasibility of start-up of the anammox process by seeding the reactor with aerobic granular sludge by using an upflow anaerobic sludge blanket (UASB) reactor. After the successful start-up and the formation of anammox granules, the structure and physicochemical properties of the anammox granules and the reactor performance were characterized. Microbial community analysis revealed that the dominant anammox species was related to a species of anammox bacteria present in anammox biofilms.     

Granulation and Sludge Bed Stability in Upflow Anaerobic Sludge Bed Reactors in Relation to Surface Thermodynamics

Adhesion of bacteria involved in anaerobic consortia was investigated in upflow anaerobic sludge bed reactors and was related to surface thermodynamics. The adhesion of hydrophilic cells appeared to be enhanced at a low liquid surface tension ((gamma)(infLV)), while the adhesion of hydrophobic cells was favored at a high (gamma)(infLV). Growth in protein-rich growth media resulted in low granular biomass yields; addition of polycations, such as poly-l-lysine and chitosan, increased the (gamma)(infLV) and the granular biomass yield. On the basis of the results of activity tests and microbial counts with wash-out cells, we identified two types of structured granules that were related to the influence of (gamma)(infLV). In one type of granules, hydrophilic acidogens surrounded a more hydrophobic methanogenic association. These granules were selected at a low (gamma)(infLV) provided that carbohydrates were available as substrates. The other type of granules was selected at a high (gamma)(infLV); hydrophobic cells (i.e., methanogens) were predominant throughout these granules. The granules which had acidogens as solid-phase emulsifiers around a methanogenic association appeared to allow more stable reactor performance. Decreasing the (gamma)(infLV) in the reactor by adding trace amounts of a surfactant also increased reactor stability.     

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria.     

Improved Dechlorinating Performance of Upflow Anaerobic Sludge Blanket Reactors by Incorporation of Dehalospirillum multivorans into Granular Sludge

Dechlorination of tetrachloroethene, also known as perchloroethylene (PCE), was investigated in an upflow anaerobic sludge blanket (UASB) reactor after incorporation of the strictly anaerobic, reductively dechlorinating bacterium Dehalospirillum multivorans into granular sludge. This reactor was compared to the reference 1 (R1) reactor, where the granules were autoclaved to remove all dechlorinating abilities before inoculation, and to the reference 2 (R2) reactor, containing only living granular sludge. All three reactors were fed mineral medium containing 3 to 57 μM PCE, 2 mM formate, and 0.5 mM acetate and were operated under sterile conditions. In the test reactor, an average of 93% (mole/mole) of the effluent chloroethenes was dichloroethene (DCE), compared to 99% (mole/mole) in the R1 reactor. The R2 reactor, with no inoculation, produced only trichloroethene (TCE), averaging 43% (mole/mole) of the effluent chloroethenes. No dechlorination of PCE was observed in an abiotic control consisting of sterile granules without inoculum. During continuous operation with stepwise-reduced hydraulic retention times (HRTs), both the test reactor and the R1 reactor showed conversion of PCE to DCE, even at HRTs much lower than the reciprocal maximum specific growth rate of D. multivorans, indicating that this bacterium was immobilized in the living and autoclaved granular sludge. In contrast, the R2 reactor, with no inoculation of D. multivorans, only converted PCE to TCE under the same conditions. Immobilization could be confirmed by using fluorescein-labeled antibody probes raised against D. multivorans. In granules obtained from the R1 reactor, D. multivorans grew mainly in microcolonies located in the centers of the granules, while in the test reactor, the bacterium mainly covered the surfaces of granules.     

Anaerobic Granular Sludge Bioreactor Technology

Anaerobic digestion is a mature wastewater treatment technology, with worldwide application. The predominantly applied bioreactor designs, such as the upflow anaerobic sludge blanket and expanded granular sludge bed, are based on the spontaneous formation of granular sludge. Despite the exploitation of granular reactors at full-scale for more than two decades, the mechanisms of granulation are not completely understood and numerous theories have been put forward to describe the process from a biological, ecological and engineering point of view. New technological opportunities are emerging for anaerobic digestion, aided by an improved understanding of microbiological and environmental factors affecting the formation and activity of anaerobic granular sludge.     

Degradation of Methanethiol by Methylotrophic Methanogenic Archaea in a Lab-Scale Upflow Anaerobic Sludge Blanket Reactor

In a lab-scale upflow anaerobic sludge blanket reactor inoculated with granular sludge from a full-scale wastewater treatment plant treating paper mill wastewater, methanethiol (MT) was degraded at 30°C to H₂S, CO₂, and CH₄. At a hydraulic retention time of 9 h, a maximum influent concentration of 6 mM MT was applied, corresponding to a volumetric loading rate of 16.5 mmol liter⁻¹ day⁻¹. The archaeal community within the reactor was characterized by anaerobic culturing and denaturing gradient gel electrophoresis analysis, cloning, and sequencing of 16S rRNA genes and quantitative PCR. Initially, MT-fermenting methanogenic archaea related to members of the genus Methanolobus were enriched in the reactor. Later, they were outcompeted by Methanomethylovorans hollandica, which was detected in aggregates but not inside the granules that originated from the inoculum, the microbial composition of which remained fairly unchanged. Possibly other species within the Methanosarcinacaea also contributed to the fermentation of MT, but they were not enriched by serial dilution in liquid media. The archaeal community within the granules, which was dominated by Methanobacterium beijingense, did not change substantially during the reactor operation. Some of the species related to Methanomethylovorans hollandica were enriched by serial dilutions, but their growth rates were very low. Interestingly, the enrichments could be sustained only in the presence of MT and did not utilize any of the other typical substrates for methylotrophic methanogens, such as methanol, methyl amine, or dimethylsulfide.     

Methanogenesis in an Upflow Anaerobic Sludge Blanket Reactor at pH 6 on an Acetate-Propionate Mixture

High-rate anaerobic digestion can be applied in upflow anaerobic sludge blanket reactors for the treatment of various wastewaters. In upflow anaerobic sludge blanket reactors, sludge retention time is increased by a natural immobilization mechanism (viz. the formation of a granular type of sludge). When this sludge is cultivated on acid-containing wastewater, the granules mainly consist of an acetoclastic methanogen resembling Methanothrix soehngenii. This organism grows either in rods or in long filaments. Attempts to cultivate a stable sludge consisting predominantly of Methanosarcina sp. on an acetate-propionate mixture as substrate by lowering the pH from 7.5 during the start-up to approximately 6 failed. After 140 days of continuous operation of the reactor a filamentous organism resembling Methanothrix soehngenii prevailed in the sludge. The specific methanogenic activity of this sludge on acetate-propionate was optimal at pH 6.6 to 6.8 and 7.0 to 7.2, respectively.     

Phenotypic Properties and Microbial Diversity of Methanogenic Granules from a Full-Scale Upflow Anaerobic Sludge Bed Reactor Treating Brewery Wastewater

Methanogenic granules from an anaerobic bioreactor that treated wastewater of a beer brewery consisted of different morphological types of granules. In this study, the microbial compositions of the different granules were analyzed by molecular microbiological techniques: cloning, denaturing gradient gel electrophoresis and fluorescent in situ hybridization (FISH), and scanning and transmission electron microscopy. We propose here that the different types of granules reflect the different stages in the life cycle of granules. Young granules were small, black, and compact and harbored active cells. Gray granules were the most abundant granules. These granules have a multilayer structure with channels and void areas. The core was composed of dead or starving cells with low activity. The brown granules, which were the largest granules, showed a loose and amorphous structure with big channels that resulted in fractured zones and corresponded to the older granules. Firmicutes (as determined by FISH) and Nitrospira and Deferribacteres (as determined by cloning and sequencing) were the predominant Bacteria. Remarkably, Firmicutes could not be detected in the brown granules. The methanogenic Archaea identified were Methanosaeta concilii (70 to 90% by FISH and cloning), Methanosarcina mazei, and Methanospirillum spp. The phenotypic appearance of the granules reflected the physiological condition of the granules. This may be valuable to easily select appropriate seed sludges to start up other reactors.