An investigation of anthraquinone dye biodegradation by immobilized Aspergillus flavus in fluidized bed bioreactor

Purpose

Biodegradation and biodecolorization of Drimarene blue K₂RL (anthraquinone) dye by a fungal isolate Aspergillus flavus SA2 was studied in lab-scale immobilized fluidized bed bioreactor (FBR) system.

Method

Fungus was immobilized on 0.2-mm sand particles. The reactor operation was carried out at room temperature and pH?5.0 in continuous flow mode with increasing concentrations (50, 100, 150, 200, 300, 500?mg?l^?1) of dye in simulated textile effluent on the 1st, 2nd, 5th, 8th, 11th, and 14th days. The reactors were run on fill, react, settle, and draw mode, with hydraulic retention time (HRT) of 24?C72?h. Total run time for reactor operation was 17?days.

Results

The average overall biological oxygen demand (BOD), chemical oxygen demand (COD), and color removal in the FBR system were up to 85.57%, 84.70%, and 71.3%, respectively, with 50-mg?l^?1 initial dye concentration and HRT of 24?h. Reductions in BOD and COD levels along with color removal proved that the mechanism of biodecolorization and biodegradation occurred simultaneously. HPLC and LC?CMS analysis identified phthalic acid, benzoic acid, 1, 4-dihydroxyanthraquinone, 2,3-dihydro-9,10-dihydroxy-1,4-anthracenedione, and catechol as degradation products of Drimarene blue K₂RL dye. Phytotoxicity analysis of bioreactor treatments provided evidence for the production of less toxic metabolites in comparison to the parent dye.

Conclusion

The present fluidized bed bioreactor setup with indigenously isolated fungal strain in its immobilized form is efficiently able to convert the parent toxic dye into less toxic by-products.     

Influence of the organic loading rate on the performance and the granular sludge characteristics of an EGSB reactor used for treating traditional Chinese medicine wastewater

The effects of the organic loading rate (OLR) on the performance and the granular sludge characteristics of an expanded granular sludge bed (EGSB) reactor used for treating real traditional Chinese medicine (TCM) wastewater were investigated. Over 90 % of the COD removal by the EGSB reactor was observed at the OLRs of 4 to 13 kg COD/(m³ day). However, increasing the OLR to 20 kg COD/(m³ day) by reducing the hydraulic retention time (HRT 6 h) reduced the COD removal efficiency to 78 %. The volatile fatty acid (VFA) concentration was 512.22 mg/L, resulting in an accumulation of VFAs, and propionic acid was the main acidification product, accounting for 66.51 % of the total VFAs. When the OLR increased from 10 to 20 kg COD/(m³ day), the average size of the granule sludge decreased from 469 to 258 μm. There was an obvious reduction in the concentration of Ca²⁺ and Mg²⁺ in the granular sludge. The visible humic acid-like peak was identified in the three-dimensional excitation-emission matrix (EEM) fluorescence spectra of the soluble microbial products (SMPs). The fatty acid bond, amide II bond, amide III bond, and C–H bond bending were also observed in the Fourier transform infrared (FTIR) spectra of the SMPs. Methanobacterium formicicum, Methanococcus, and Bacteria populations exhibited significant shifts, and these changes were accompanied by an increase in VFA production. The results indicated that a short HRT and high OLR in the EGSB reactor caused the accumulation of polysaccharides, protein, and VFAs, thereby inhibiting the activity of methanogenic bacteria and causing granular sludge corruption.     

UASB反应器降解活性染料废水的特性

中温（35±1）℃条件下,采用上流式厌氧污泥床（upflowanaerobicsludgebed,简称UASB）反应器处理了含蒽醌类-活性艳蓝（c．I．ReactiveBlue5,简称K—GR）或偶氮类-活性艳红（C．I．ReactiveRed20,简称KD-8B;C．I．ReactiveRed2,简称X-3B）模拟染料废水,重点研究了回流比对染料脱色率和COD去除率的影响,在最佳回流比的条件下,探讨HRT（hydraulicretentiontime）对脱色的影响和不同结构染料的脱色效果,并初步分析了脱色机理。结果表明,适宜的回流比有利于提高系统的脱色率;控制回流比和HRT分别为2和24h,当模拟废水中染料的浓度为100mg／L时,COD去除率和脱色率分别为90％～96％和85％～92％;蒽醌和偶氮类染料的脱色是通过偶氮键和葸醌共轭结构的断裂来实现的。     

Removal of organic compounds during treating printing and dyeing wastewater of different process units

Wastewater in Shaoxing wastewater treatment plant (SWWTP) is composed of more than 90% dyeing and printing wastewater with high pH and sulfate. Through a combination process of anaerobic acidogenic [hydraulic retention time (HRT) of 15h], aerobic (HRT of 20h) and flocculation-precipitation, the total COD removal efficiency was up to 91%. But COD removal efficiency in anaerobic acidogenic unit was only 4%. As a comparison, the COD removal efficiency was up to 35% in the pilot-scale upflow anaerobic sludge bed (UASB) reactor (HRT of 15h). GC-MS analysis showed that the response abundance of these wastewater samples decreased with their removal of COD. A main component of the raw influent was long-chain n-alkanes. The final effluent of SWWTP had only four types of alkanes. After anaerobic unit at SWWTP, the mass percentage of total alkanes to total organic compounds was slightly decreased while its categories increased. But in the UASB, alkanes categories could be removed by 75%. Caffeine as a chemical marker could be detected only in the effluent of the aerobic process. Quantitative analysis was given. These results demonstrated that GC-MS analysis could provide an insight to the measurement of organic compounds removal.     

Simultaneous nitrification and denitrification of municipal wastewater in aerobic membrane bioreactors.

Simultaneous nitrification-denitrification (SND) of municipal wastewater was investigated in a laboratory-scale membrane bioreactor (MBR) operated at two different hydraulic retention times (HRTs), 0.5 and 1 day, dissolved oxygen 3.0 to 0.5 mg/L, and solids retention time (SRT) between 28 and 120 days. The organic loading rate (OLR) (0.11 to 0.64 kg chemical oxygen demand [COD]/m3/d) and influent soluble COD (SCOD)/ total Kjeldahl nitrogen (TKN) ratio (5 to 19) were varied by the addition of glucose. The ammonia-nitrogen and TKN removals were over 97%, and total nitrogen removal was approximately 89% in the MBR. The maximum specific nitrification rates (98 mg N/d/g VSS) and specific denitrification rates (81 mg N/d/g VSS) occurred at an SCOD/TKN ratio of 9.1. The optimum conditions for maximum total nitrogen removal by SND in a single reactor MBR have been found to be low dissolved oxygen (< 0.6 mg/L) and high OLR (approximately 0.64 kg COD/m3/d) at an HRT of 0.5 day and SRT of approximately 85 days.     

生物膜反应器连续处理餐饮废水

用生物膜反应器连续处理餐水能有效降低废水中的ＢＯＤ及ＣＯＤ浓度。研究了水力停留时间对有机物去除率的影响,结果表明当水力停留时间大于７．８ｈ时,废水的ＣＯＤ,ＢＯＤ及ＴＳＳ的去除率均高于９０％。实验操作时,水力停留时间应略大于５．７ｈ。     

铁屑法处理活性染料废水的实验研究

研究了反应时间、染料浓度、进水pH以及不同的废铸铁屑投加量的条件下，废铸铁屑内电解法处理模拟印染废水的脱色能力。并采用铁屑滤床强化厌氧一好氧膜生物反应器（A／OMBR）处理含活性染料的模拟废水。研究结果表明，铁屑对模拟印染废水的最佳脱色时间为12min，酸性条件下铁屑的脱色率优于碱性条件．随铁屑投加量的增加，系统对印染废水的脱色率提高，铁屑滤床强化A／OMBR处理可以提高组合工艺出水色度和COD的去除率。     

混凝辅助电化学法处理橙黄G染料废水

以石墨板为阳极,研究了电化学氧化法对橙黄G染料废水的降解效果。比较了在NaCl、Na2 SO4以及NaCl与FeSO4·7H2O组合的支持电解质体系中的处理效果,同时考察了电压、初始pH、电解质浓度、电极间距和电解时间等因素对废水中橙黄G脱色率及COD去除率的影响。研究结果表明,橙黄G的脱色主要是活性氯的氧化作用,橙黄G分子的矿化可能主要是电解过程中产生的·OH的作用,FeSO4·7H2O的加入增加了混凝作用,使得处理效果进一步提高。最佳脱色条件下橙黄G脱色率和COD的去除率分别为97．6％和56．3％,B／C（BOD／COD）由0．09提高至0．41,可生化性有较大改善,并且随着降解时间的增加,COD去除率逐渐升高。此结果表明,橙黄G废水COD的去除相对于脱色存在滞后性。     

缺氧-好氧生物滤池中高效菌对活性红KN-3B的降解特性

为了研究高效脱色菌在缺氧好氧生物滤池（A/O biofilter）中对偶氮染料的降解特性,以活性红KN-3B（C.I. reactive red 180）为降解对象,缺氧生物滤池以火山碎石为填料,接种高效脱色菌CK3柯氏柠檬酸杆菌启动,好氧生物滤池以牡蛎壳为填料,接种污水处理厂活性污泥启动。试验考察了不同工况下缺氧-好氧生物滤池对色度和COD的去除效果,结果表明：生物滤池中微生物对偶氮染料活性红KN-3B的脱色和对COD降解的最适pH条件为弱酸性;缺氧滤池中高效菌对色度的去除需要外加碳源,且增加外加碳源有助于脱色率的提高;该高效菌为耐盐菌,当进水NaCl浓度达30 g/L时,色度去除率仍可达93%以上;当染料负荷达500 mg/L时,脱色率仍可达95%。通过紫外-可见扫描图谱分析初步推断CK-3柯氏柠檬酸杆菌对偶氮染料活性红KN-3B的脱色主要是生物降解作用。     

Assessment of sewage sludge bioremediation at different hydraulic retention times using mixed fungal inoculation by liquid-state bioconversion

Sustainable, environmental friendly, and safe disposal of sewage treatment plant (STP) sludge is a global expectation. Bioremediation performance was examined at different hydraulic retention times (HRT) in 3–10 days and organic loading rates (OLR) at 0.66–7.81 g chemical oxygen demand (COD) per liter per day, with mixed filamentous fungal (Aspergillus niger and Penicillium corylophilum) inoculation by liquid-state bioconversion (LSB) technique as a continuous process in large-scale bioreactor. Encouraging results were monitored in treated sludge by LSB continuous process. The highest removal of total suspended solid (TSS), turbidity, and COD were achieved at 98, 99, and 93 %, respectively, at 10 days HRT compared to control. The minimum volatile suspended solid/suspended solid implies the quality of water, which was recorded 0.59 at 10 days and 0.72 at 3 days of HRT. In treated supernatant with 88 % protein removal at 10 days of HRT indicates a higher magnitude of purification of treated sludge. The specific resistance to filtration (SRF) quantifies the performance of dewaterability; it was recorded minimum 0.049 × 10¹² m kg^?1 at 10 days of HRT, which was equivalent to 97 % decrease of SRF. The lower OLR and higher HRT directly influenced the bioremediation and dewaterability of STP sludge in LSB process. The obtained findings imply encouraging message in continuing treatment of STP sludge, i.e., bioremediation of wastewater for environmental friendly disposal in near future.     

AFB-SBR工艺处理蓝皮制革工业废水

采用厌氧流化床(AFB)-序批式反应器(SBR)工艺处理蓝皮制革工业废水。分别考察了水力停留时间(HRT)、容积负荷对厌氧流化床以及曝气时间、污泥浓度、溶解氧浓度对SBR反应器处理效果的影响。试验结果表明,AFB将实验废水的BOD_5/COD(B/C)值由0.19～0.26提高至0.35～0.42,有效提高了其可生化性;在进水COD浓度为1 700～1 890 mg/L、HRT为1 d、容积负荷为1.792 kg COD/(m~3·d)时,COD去除率达65.2%～68.5%,且具有良好的抗冲击负荷能力。SBR在进水COD浓度为628～712 mg/L、污泥浓度为2.9 g/L、曝气时间为10 h、溶解氧浓度为2 mg/L工况下,COD去除率达87.6%,NH_3-N去除率达93.6%,处理后出水水质符合污水综合排放标准(GB 8978-1996)中的一级标准要求。     

混凝-催化氧化-水解酸化-生物接触氧化法处理染料废水的中试研究

采用混凝-催化氧化-水解酸化-生物接触氧化法处理高浓度难降解分散染料废水.比较分析了O_3、UV/TiO_2/O_3,UV/O_3/H_2O_23种高级氧化法的处理效果.结果表明,UV/TiO_2/O_3对废水COD和色度有较高的去除率.可明显改善废水的可生化性,废水的BOD_5/COD由0.05～0.07升高至0.42～0.46.在混凝沉淀单元HRT为1.5 h.催化氧化单元(UV/TiO_2/O_3)HRT为3.0 h,水解酸化HRT为10.0 h,生物接触氧化HRT为10.0 h的最佳条件下,该组合工艺对废水COD和色度总的去除率分别可达95.0%、99.5%.     

UASB反应器处理链霉素废水启动及运行性能

采用上流式厌氧污泥床(UASB)反应器处理链霉素生产废水,研究了中温条件下反应器启动和稳定运行中废水处理性能及厌氧污泥颗粒化过程。结果表明,通过逐步提高链霉素废水进水比例和负荷,可以实现UASB反应器的启动和稳定运行,并对高浓度链霉素实际废水具有良好的处理性能,COD去除率稳定在80%以上,COD去除负荷达7.2 kg/(m3·d),CH4产生量达到6.2 L/d。UASB反应器启动运行过程中,链霉素废水对污泥活性具有抑制影响,造成短期反应器运行性能明显下降,而后很快恢复。同时高负荷链霉素废水造成甲烷产率降低。污泥性状变化显著,污泥形态逐渐转变为颗粒态,污泥粒径增大,出现大量0.5~1.0 mm颗粒污泥,污泥VSS/SS比值升高,污泥沉降性明显增强,比产甲烷活性显著升高,表明污泥开始实现颗粒化。     

外循环式UASB反应器处理槟榔废水

在中温（35±2℃）条件下,利用外循环式UASB反应器处理中高有机浓度的槟榔加工废水,并着重探讨了水力停留时间（HRT）对厌氧消化的影响。研究表明,当反应器稳定运行,水力停留时间为1 d,进水COD浓度5 000 mg/L左右,容积负荷在2.53-5.25 kg COD/（m3·d）时,COD去除率在38%以上,出水COD〈3 000 mg/L,平均产气率为0.41 m3/kg COD;若水力停留时间延长至4 d,容积负荷为1.26-1.30 kg COD/（m3·d）,COD去除率可以达到79%,出水COD〈1 200 mg/L,出水可生化性下降,BOD5/COD平均为0.28,实验取得了良好的处理效果,为利用厌氧技术处理槟榔加工废水提供了设计依据。     

内循环(IC)厌氧反应器处理糖蜜酒精废水的研究

糖蜜酒精废水由于含有高浓度的COD和硫酸盐,一般厌氧反应器无法有效处理.研究了IC反应器处理糖蜜酒精废水的效果.考察其COD及硫酸盐的去除率、沼气的产量和组分等.结果表明,反应器对于COD为5000～10 000 mg/L的中、高浓度废水去除效果良好,当COD在20 000～30 000 mg/L时,在适应了1～2个停留时间后,去除效果达到稳定,去除率在90%左右.实验中最高容积负荷提升至40 kg COD/m3·d左右.本研究中所用的糖蜜酒精废水的COD/SO24-的平均值为61.9,未对反应器的处理效果及产气量产生影响.     

Biological treatment of dye wastewaters using an anaerobic-oxic system

Three dye solutions, namely, C.I. Acid Yellow 17, C.I. Basic Blue 3, and C.I. Basic Red 2, were treated in an upflow anaerobic sludge blanket (UASB) reactor followed by a semi-continuous aerobic activated sludge tank. When hydraulic retention time was about 12 hours, no significant color removal was observed in the aerobic stage. In the anaerobic stage, Acid Yellow 17, Basic Blue 3, and Basic Red 2 were removed by 20%, 72%, and 78%, respectively. To treat wastewater from a dye manufacturing factory with COD concentration of 1200 mg/l and Color of 500 degree (dilution factor), an UASB reactor (4.5 liters) and an activated sludge tank (5 liters, adjustable), COD and color were removed by more than 83% and 90% at a COD loading rate of 5.3 kg COD/m³-day in the anaerobic stage, and at the hydraulic retention time of 6-10 hours for the anaerobic stage and 6.5 for the aerobic stage. The anaerobic stage of the A/O system removes both color and COD. In addition, it also improves biodegradability of dyes for further aerobic treatment.     

Critical effect of hydrogen peroxide concentration in photochemical oxidative degradation of C.I. Acid Red 27 (AR27)

The photochemical decolorization of C.I. Acid Red 27 (AR27), an anionic monoazo dye, was studied in the UV/H2O2 process by using a batch reactor with a UV-C lamp emitting at 254 nm (30 W). The decolorization rate follows pseudo-first order kinetic with respect to the AR27 concentration. The results indicate that the apparent reaction rate constant in the UV/H2O2 process is a function of H2O2 concentration. In this work, a mathematical relation between the apparent reaction rate constant of the AR27 removal and used H2O2 was established. The applied amount of H2O2 was performed in two forms: (i) the light fraction absorbed by H2O2 in 254 nm, (ii) the initial concentration ratio of H2O2 to AR27. The results obtained from this mathematical model are in good agreement with experimental results.     

笼状填料式厌氧折流反应器处理啤酒废水

以ABR反应器为基础,采用笼状填料,增加了缺氧与好氧段,设计了新型的ABR;以啤酒废水为处理对象,考察了新型反应器的启动过程,研究了新型反应器对废水COD的去除效果,分析了HRT、有机容积负荷对COD去除的影响,探讨了新型反应器处理过程中的pH变化及其原因,阐述了笼状填料截留和微生物的附着生长是出水SS较低的原因,出水氨氮浓度较低是增设的缺氧段和好氧段共同作用的结果。实验结果表明,其COD去除效率达96%,有机容积负荷约0.647～1.745 kg/(m3.d);当进水量为50 L/d时,其出水水质达到啤酒废水排放标准。     

厌氧滤池处理纺织印染废水的中试研究

对厌氧滤池反应器处理难降解印染废水进行中试研究。结果表明,厌氧滤池反应器水力停留时间(HRT)在8.1～14.6 h之间,进水COD浓度波动较大(500～1 000 mg/L)时,对COD平均去除率为20%。印染废水的BOD5/COD由0.23提高到0.35,废水可生化性明显改善。印染废水中硫酸根浓度略有下降,去除浓度为70 mg/L左右。厌氧滤池进出水颜色明显变化,由紫红色变为蓝黑色,紫外可见光谱分析表明废水中的有机物结构发生变化。     

Performance evaluation of sequencing batch reactor for beverage industrial wastewater treatment

Attempts were made in this study to examine the effectiveness of sequencing batch reactor (SBR) for the treatment of beverage industrial wastewater. The SBR was operated at three different organic loading rates (OLRs): 2, 1.7 and 1.1 kg COD/m3 d. Results of continuous long-term operation showed that by decreasing OLR from 2 to 1.7 kg COD/m3 day, the removal efficiency was increased from 95.5 to 99.3% for COD, from 95.3 to 98.1% for BOD and from 87 to 97.7% for TSS. While further decreasing of the OLR to 1.1 kg COD/m3 day, there is no significant adverse effect on organics removal. Also, residual total nitrogen (TN) concentration decreased by decreasing the OLR. However, increasing the OLRs exerted a slightly negative effect on the removal of total phosphorous. On the other hand, the experimental data indicated that the substrate utilization kinetic followed Monod's kinetics model approximately. The maximum specific substrate utilization rate (micro(max), half velocity coefficient (Ks), growth yield coefficient (Y) and decay coefficient (Kd) were 2.94 d(-1), 15.22 mg/L, 0.2384 g VSS/g COD and 0.2019 h(-1), respectively.