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Bessa VS, Moreira IS, Van Loosdrecht MCM, Castro PML. Biological removal processes in aerobic granular sludge exposed to diclofenac. ENVIRONMENTAL TECHNOLOGY 2022; 43:3295-3308. [PMID: 33902395 DOI: 10.1080/09593330.2021.1921048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 04/14/2021] [Indexed: 06/12/2023]
Abstract
Diclofenac is a worldwide consumed drug included in the watch list of substances to be monitored according to the European Union Water Framework Directive (Directive 2013/39/EU). Aerobic granular sludge sequencing batch reactors (AGS-SBR) are increasingly used for wastewater treatment but there is scant information on the fate and effect of micropollutants to nutrient removal processes. An AGS-SBR fed with synthetic wastewater containing diclofenac was bioaugmented with a diclofenac degrading bacterial strain and performance and microbial community dynamics was analysed. Chemical oxygen demand, phosphate and ammonia removal were not affected by the micropollutant at 0.03 mM (9.54 mg L-1). The AGS was able to retain the degrading strain, which was detected in the sludge throughout after augmentation. Nevertheless, besides some adsorption to the biomass, diclofenac was not degraded by the augmented sludge given the short operating cycles and even if batch degradation assays confirmed that the bioaugmented AGS was able to biodegrade the compound. The exposure to the pharmaceutical affected the microbial community of the sludge, separating the two first phases of reactor operation (acclimatization and granulation) from subsequent phases. The AGS was able to keep the bioaugmented strain and to maintain the main functions of nutrient removal even through the long exposure to the pharmaceutical, but combined strategies are needed to reduce the spread of micropollutants in the environment.
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Affiliation(s)
- Vânia S Bessa
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal
| | - Irina S Moreira
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal
| | | | - Paula M L Castro
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal
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Sun Y, Angelotti B, Brooks M, Wang ZW. Feast/famine ratio determined continuous flow aerobic granulation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 750:141467. [PMID: 32853933 DOI: 10.1016/j.scitotenv.2020.141467] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/01/2020] [Accepted: 08/02/2020] [Indexed: 06/11/2023]
Abstract
Plug flow reactors (PFRs) made of multiple completely stirred tank reactors (CSTRs) in series were used to cultivate aerobic granules in real domestic wastewater. Theoretically, changing the number of CSTR chambers in series will change the nature of plug flow, and thus alter the pattern of the feast/famine condition and impact the aerobic granulation progress. Therefore, PFRs were operated in 4-, 6-, and 8-chamber mode under the same gravity selection pressure (a critical settling velocity of 9.75 m h-1) and hydraulic retention time (6.5 h) until steady states were reached to evaluate the effect of the feast/famine condition on continuous flow aerobic granulation. The sludge particle size, circularity, settleability, specific gravity, zone settling velocity, and extracellular polymeric substance contents were analyzed to evaluate the role that a feast/famine regime plays in aerobic granulation. It was found that aerobic granulation failed whenever the feast/famine ratio was greater than 0.5. The results support a conclusion that the feast/famine condition is likely a prerequisite for continuous flow aerobic granulation.
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Affiliation(s)
- Yewei Sun
- Occoquan Laboratory, Department of Civil and Environmental Engineering, Virginia Tech, 9408 Prince William Street, Manassas, VA 20110, USA; Hazen and Sawyer, 4035 Ridge Top Road, Suite 500, Farfax, VA 22030, USA
| | - Bob Angelotti
- Upper Occoquan Service Authority, 14631 Compton Rd, Centreville, VA 20121, USA
| | - Matt Brooks
- Upper Occoquan Service Authority, 14631 Compton Rd, Centreville, VA 20121, USA
| | - Zhi-Wu Wang
- Occoquan Laboratory, Department of Civil and Environmental Engineering, Virginia Tech, 9408 Prince William Street, Manassas, VA 20110, USA.
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3
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Wang L, Zhan H, Wu G, Zeng Y. Effect of operational strategies on the rapid start-up of nitrogen removal aerobic granular system with dewatered sludge as inoculant. BIORESOURCE TECHNOLOGY 2020; 315:123816. [PMID: 32688252 DOI: 10.1016/j.biortech.2020.123816] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
In both sequencing batch reactors with dewatering sludge as inoculant, the strategies by step-feeding (R1) or step-feeding combined with low aeration (R2) were performed under alternating anoxic/aerobic condition to discover superior methods launching nitrogen removal aerobic granule system. Interestingly, two reactors accomplished granulation at day 0, two days later, possessed prominent settling performance (SVI < 45 ml/g. MLSS) and denitrifying ability (TIN > 80%). Thereinto, R2 had lower crushing rate, larger granules, higher biomass and better pollutant removal performance owing to low aeration and more filamentous bacteria on AGS surface. Moreover, effluent NH4+-N was used as indicator of excess filaments due to its quick response for the filaments. After effluent NH4+-N exceeded 5 mg/L, causative filaments Sphaerotilus were effectively inhibited and eliminated by enhancing pH value to 8.0 ± 0.2. As a result, this study provides a new insight into rapid start-up nitrogen removal granule system by promoting and limiting filaments in proper period.
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Affiliation(s)
- Lei Wang
- School of Civil Engineering, Southwest Jiaotong University, 610031 Chengdu, China; School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China.
| | - Hanhui Zhan
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China
| | - Gang Wu
- School of Life Science and Engineering, Southwest Jiaotong University, 610031 Chengdu, China
| | - Yong Zeng
- School of Civil Engineering, Southwest Jiaotong University, 610031 Chengdu, China
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4
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Ahmad JSM, Zhao Z, Zhang Z, Shimizu K, Utsumi M, Lei Z, Lee DJ, Tay JH. Algal-bacterial aerobic granule based continuous-flow reactor with effluent recirculation instead of air bubbling: Stability and energy consumption analysis. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2019.100215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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5
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Anand A, Sato M, Aoyagi H. Screening of Phosphate-accumulating Probiotics for Potential Use in Chronic Kidney Disorder. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2019. [DOI: 10.3136/fstr.25.89] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Ajeeta Anand
- Institute of Life Sciences and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba
| | - Mayuko Sato
- Institute of Life Sciences and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba
| | - Hideki Aoyagi
- Institute of Life Sciences and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba
- Faculty of Life and Environmental Sciences, University of Tsukuba
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6
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Ren X, Chen Y, Guo L, She Z, Gao M, Zhao Y, Shao M. The influence of Fe 2+, Fe 3+ and magnet powder (Fe 3O 4) on aerobic granulation and their mechanisms. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 164:1-11. [PMID: 30092387 DOI: 10.1016/j.ecoenv.2018.07.072] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 06/08/2023]
Abstract
This study aimed to develop an aerobic granular sludge and understand the granulation process of the multi-iron ions. Four sequencing batch reactors (SBRs) were applied to elucidate the effect of Fe2+, Fe3+ and Fe3O4 addition on aerobic granulation. The results confirmed that the start-up time of aerobic granulation with Fe3O4 addition (11 days) was notably less than that with Fe2+ (16 days) and Fe3+ (27 days) addition. Larger granules achieved with Fe3O4 addition with a sludge volume index (SVI30) of 28.50 mL/g and settling velocity of 49.68 m/h. Scanning electron microscope (SEM) analysis further revealed that the presence of mineral crystal in the granule core with Fe2+ and Fe3O4 addition accelerated the granule formation and maintained the stability of the structure. Extracellular polymeric substances (EPS) were studied using three-dimensional-excitation emission matrix (3D-EEM) fluorescence spectra technology to gain a comprehensive view of the interactions between EPS and Fe2+, Fe3+ and Fe3O4. Around 94.76% and 97.68% removal rate was noted for COD and ammonia in the granulation process. Finally, the dominant functional species involved in biological nutrients removal and granule formation were identified by high throughput sequencing technology to assess the effects of Fe2+, Fe3+ and Fe3O4 to granule at the molecular level.
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Affiliation(s)
- Xiaomin Ren
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yue Chen
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Liang Guo
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China; Key Laboratory of Marine Environmental and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China.
| | - Zonglian She
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Mengchun Gao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yangguo Zhao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Mengyu Shao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
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7
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He Q, Chen L, Zhang S, Wang L, Liang J, Xia W, Wang H, Zhou J. Simultaneous nitrification, denitrification and phosphorus removal in aerobic granular sequencing batch reactors with high aeration intensity: Impact of aeration time. BIORESOURCE TECHNOLOGY 2018; 263:214-222. [PMID: 29747098 DOI: 10.1016/j.biortech.2018.05.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 06/08/2023]
Abstract
A new operating approach by reducing the aeration time while keeping high intensity was evaluated for enhanced nutrients removal and maintenance of granular stability. Three aerobic granular sequencing batch reactors (SBR) performing simultaneous nitrification, denitrification and phosphorus removal (SNDPR) were run at different aeration time (120, 90, and 60 min). Aerobic granules could remain their integrity and stability over long-term operation under high aeration intensity and different time, and shorter aeration time favored the retention of biomass, better settleability, and more production of extracellular polymeric substances (EPS). Besides, efficient and stable reactor performance for carbon and phosphorus were achieved, especially, enhanced nitrogen removal was obtained due to reduction of aeration time. Further exploration revealed that the aeration time shaped the bacterial community in terms of diversity, composition, as well as the distribution of functional groups involving carbon, nitrogen and phosphorus removal.
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Affiliation(s)
- Qiulai He
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Li Chen
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Shujia Zhang
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Li Wang
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Jiawen Liang
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Wenhao Xia
- School of Civil Engineering, Wuhan University, Wuhan 430072, China
| | - Hongyu Wang
- School of Civil Engineering, Wuhan University, Wuhan 430072, China.
| | - Jinping Zhou
- College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China
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8
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Wang J, Zhang Z, Qian F, Shen Y, Qi Z, Ji X, Kajamisso EML. Rapid start-up of a nitritation granular reactor using activated sludge as inoculum at the influent organics/ammonium mass ratio of 2/1. BIORESOURCE TECHNOLOGY 2018; 256:170-177. [PMID: 29438917 DOI: 10.1016/j.biortech.2018.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 06/08/2023]
Abstract
Partial oxidation of ammonium to nitrite is a pre- and crucial step to achieve shortcut biological nitrogen removal from ammonium-rich wastewater. In the present study, a nitritation granular reactor using activated sludge as inoculum was started up in a sequencing batch reactor (SBR) at a fixed influent C/N ratio of 2:1. Variations in the reactor performance, functional bacteria activities, sludge morphology and bacterial community structure were investigated. Results showed the formation of compact granules was achieved in 55 days, and a stable nitrite accumulation rate of 0.68 kg N·m-3·d-1 was maintained in the following period. With a rapid growth of granular size, the total nitrogen removal by simultaneous nitritation/denitritation was progressively increased to 50%. In sludge granulation, the significant enrichment of r-strategist ammonium oxidizing bacteria (Nitrosomonas) was identified. Additionally, both high free ammonia concentration and extra nitrite competition by heterotrophic denitrifiers were critical to suppress nitrite oxidizing bacteria effectively.
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Affiliation(s)
- Jianfang Wang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Zeyu Zhang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Feiyue Qian
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China.
| | - Yaoliang Shen
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Zekun Qi
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Xiaoqing Ji
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Emma Marcello Lagu Kajamisso
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
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9
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Wilén BM, Liébana R, Persson F, Modin O, Hermansson M. The mechanisms of granulation of activated sludge in wastewater treatment, its optimization, and impact on effluent quality. Appl Microbiol Biotechnol 2018; 102:5005-5020. [PMID: 29705957 PMCID: PMC5960003 DOI: 10.1007/s00253-018-8990-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/14/2022]
Abstract
Granular activated sludge has gained increasing interest due to its potential in treating wastewater in a compact and efficient way. It is well-established that activated sludge can form granules under certain environmental conditions such as batch-wise operation with feast-famine feeding, high hydrodynamic shear forces, and short settling time which select for dense microbial aggregates. Aerobic granules with stable structure and functionality have been obtained with a range of different wastewaters seeded with different sources of sludge at different operational conditions, but the microbial communities developed differed substantially. In spite of this, granule instability occurs. In this review, the available literature on the mechanisms involved in granulation and how it affects the effluent quality is assessed with special attention given to the microbial interactions involved. To be able to optimize the process further, more knowledge is needed regarding the influence of microbial communities and their metabolism on granule stability and functionality. Studies performed at conditions similar to full-scale such as fluctuation in organic loading rate, hydrodynamic conditions, temperature, incoming particles, and feed water microorganisms need further investigations.
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Affiliation(s)
- Britt-Marie Wilén
- Division of Water Environment Technology, Department of Architecture and Civil and Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
| | - Raquel Liébana
- Division of Water Environment Technology, Department of Architecture and Civil and Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Frank Persson
- Division of Water Environment Technology, Department of Architecture and Civil and Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Oskar Modin
- Division of Water Environment Technology, Department of Architecture and Civil and Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Malte Hermansson
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-405 30, Gothenburg, Sweden
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10
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Franca RD, Pinheiro HM, van Loosdrecht MC, Lourenço ND. Stability of aerobic granules during long-term bioreactor operation. Biotechnol Adv 2018; 36:228-246. [DOI: 10.1016/j.biotechadv.2017.11.005] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/30/2017] [Accepted: 11/14/2017] [Indexed: 10/18/2022]
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11
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Hasebe Y, Meguro H, Kanai Y, Eguchi M, Osaka T, Tsuneda S. High-rate nitrification of electronic industry wastewater by using nitrifying granules. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2017; 76:3171-3180. [PMID: 29210703 DOI: 10.2166/wst.2017.431] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nitrifying granules have a high sedimentation property and an ability to maintain a large amount of nitrifying bacteria in a reaction tank. Our group has examined the formation process of nitrifying granules and achieved high-rate nitrification for an inorganic synthetic wastewater using these granules. In this research, a pilot-scale test plant with an 850-liter reaction tank was assembled in a semiconductor manufacturing factory in order to conduct a continuous water conduction test using real electronics industry wastewater. The aim was to observe the formation of nitrifying granules and determine the maximum ammonia removal rate. The average granule diameter formed during the experiment was 780 μm and the maximum ammonia removal rate was observed to be 1.5 kgN·m-3·day-1 at 20 °C, which is 2.5-5 times faster than traditional activated sludge methods. A fluorescence in situ hybridization analysis showed that β-proteobacterial ammonia oxidizing bacteria and the Nitrospira-like nitrite-oxidizing bacteria dominate the bacteria population in the granules, and their strong aggregation capacity might confer some benefits to the formation of these nitrifying granules.
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Affiliation(s)
- Yoshiaki Hasebe
- Organo Corp. R&D Center, Nishioonuma 4-4-1, Minami-ku, Sagamihara 252-0332, Japan E-mail:
| | - Hiroaki Meguro
- Organo Corp. R&D Center, Nishioonuma 4-4-1, Minami-ku, Sagamihara 252-0332, Japan E-mail:
| | - Yuuki Kanai
- Organo Corp. R&D Center, Nishioonuma 4-4-1, Minami-ku, Sagamihara 252-0332, Japan E-mail:
| | - Masahiro Eguchi
- Organo Corp. R&D Center, Nishioonuma 4-4-1, Minami-ku, Sagamihara 252-0332, Japan E-mail:
| | - Toshifumi Osaka
- Department of Life Science and Medical Bioscience, Waseda Univ., Wakamatsu-cho 2-2, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Satoshi Tsuneda
- Department of Life Science and Medical Bioscience, Waseda Univ., Wakamatsu-cho 2-2, Shinjuku-ku, Tokyo 162-8480, Japan
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12
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Ahmad JSM, Cai W, Zhao Z, Zhang Z, Shimizu K, Lei Z, Lee DJ. Stability of algal-bacterial granules in continuous-flow reactors to treat varying strength domestic wastewater. BIORESOURCE TECHNOLOGY 2017; 244:225-233. [PMID: 28779675 DOI: 10.1016/j.biortech.2017.07.134] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/21/2017] [Accepted: 07/23/2017] [Indexed: 06/07/2023]
Abstract
Stability of algal-bacterial granules was investigated in two continuous-flow systems to treat synthetic domestic wastewater using single (R1) and series (R2=R2-1+R2-2 with automatically internal recirculation) reactors by seeding 50% (w/w) algal-bacterial granules. Almost similar organics and phosphorus removal efficiencies were obtained from the two systems, with no significant difference found for each between the designed two operation stages. However, R2 exhibited superior performance on total nitrogen (TN) removal (76%). When double increased strength influent fed to R1, R1 achieved better denitrification with TN removal increased from 29% to 80%, possibly due to the increased influent organics concentration favored the denitrification process. Most importantly, the two systems well maintained their granular stability, and all granules became algal-bacterial ones with very little change detected in algae content in granules after 120days' operation. At last, the mechanisms were proposed regarding the formation and enhanced stability of new algal-bacterial granules in continuous-flow reactors.
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Affiliation(s)
- Johan Syafri Mahathir Ahmad
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan; Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jl. Grafika No. 2 Kampus UGM, Yogyakarta 55281, Indonesia
| | - Wei Cai
- College of Biological and Agricultural Engineering, Jilin University, Changchun 130022, China
| | - Ziwen Zhao
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Zhenya Zhang
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Kazuya Shimizu
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Zhongfang Lei
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
| | - Duu-Jong Lee
- Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan
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13
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Effects of Inoculum Type and Aeration Flowrate on the Performance of Aerobic Granular SBRs. Processes (Basel) 2017. [DOI: 10.3390/pr5030041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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14
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Liu YQ, Tay JH. Fast formation of aerobic granules by combining strong hydraulic selection pressure with overstressed organic loading rate. WATER RESEARCH 2015; 80:256-266. [PMID: 26005786 DOI: 10.1016/j.watres.2015.05.015] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 04/01/2015] [Accepted: 05/04/2015] [Indexed: 06/04/2023]
Abstract
The combined strong hydraulic selection pressure (HSP) with overstressed organic loading rate (OLR) as a fast granulation strategy was used to enhance aerobic granulation. To investigate the wide applicability of this strategy to different scenarios and its relevant mechanism, different settling times, different inoculums, different exchange ratios, different reactor configurations, and different shear force were used in this study. It was found that clear granules were formed within 24 h and steady state reached within three days when the fast granulation strategy was used in a lab-scale reactor seeded with well settled activated sludge (Reactor 2). However, granules appeared after 2-week operation and reached steady state after one month at the traditional step-wise decreased settling time from 20 to 2 min with OLR of 6 g COD/L·d (Reactor 1). With the fast granulation strategy, granules appeared within 24 h even with bulking sludge as seed to start up Reactor 3, but 6-day lag phase was observed compared with Reactor 2. Both Reactor 2 and Reactor 3 experienced sigmoidal growth curve in terms of biomass accumulation and granule size increase after granulation. In addition, the reproducible results in pilot-scale reactors (Reactor 5 and Reactor 6) with diameter of 20 cm and height/diameter ratio (H/D) of 4 further proved that reactor configuration and fluid flow pattern had no effect on the aerobic granulation when the fast granulation strategy was employed, but biomass accumulation experienced a short lag phase too in Reactor 5 and Reactor 6. Although overstressed OLR was favorable for fast granulation, it also led to the fluffy granules after around two-week operation. However, the stable 6-month operation of Reactor 3 demonstrated that the rapidly formed granules were able to maintain long-term stability by reducing OLR from 12 g COD/L·d to 6 g COD/L·d. A mechanism of fast granulation with the strategy of combined strong HSP and OLR was proposed to explain results and guide the operation with this fast strategy.
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Affiliation(s)
- Yong-Qiang Liu
- Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, United Kingdom.
| | - Joo-Hwa Tay
- Schulich School of Engine, University of Calgary, 2500 University Dr NW, Calgary, Alberta, T2N 1N4, Canada
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15
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Dahalan FA, Abdullah N, Yuzir A, Olsson G, Hamdzah M, Din MFM, Ahmad SA, Khalil KA, Anuar AN, Noor ZZ, Ujang Z. A proposed aerobic granules size development scheme for aerobic granulation process. BIORESOURCE TECHNOLOGY 2015; 181:291-296. [PMID: 25661308 DOI: 10.1016/j.biortech.2015.01.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 06/04/2023]
Abstract
Aerobic granulation is increasingly used in wastewater treatment due to its unique physical properties and microbial functionalities. Granule size defines the physical properties of granules based on biomass accumulation. This study aims to determine the profile of size development under two physicochemical conditions. Two identical bioreactors namely Rnp and Rp were operated under non-phototrophic and phototrophic conditions, respectively. An illustrative scheme was developed to comprehend the mechanism of size development that delineates the granular size throughout the granulation. Observations on granules' size variation have shown that activated sludge revolutionised into the form of aerobic granules through the increase of biomass concentration in bioreactors which also determined the changes of granule size. Both reactors demonstrated that size transformed in a similar trend when tested with and without illumination. Thus, different types of aerobic granules may increase in size in the same way as recommended in the aerobic granule size development scheme.
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Affiliation(s)
- Farrah Aini Dahalan
- The School of Environmental Engineering, Universiti Malaysia Perlis, Kompleks Pengajian Kejuruteraan Jejawi 3, 02600 Arau, Perlis, Malaysia; Institute of Environmental and Water Resource Management (IPASA), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru, Malaysia.
| | - Norhayati Abdullah
- Palm Oil Research Centre, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Malaysia
| | - Ali Yuzir
- Institute of Environmental and Water Resource Management (IPASA), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru, Malaysia
| | - Gustaf Olsson
- Department of Industrial Electrical Engineering and Automation, Lund University, S-22100 Lund, Sweden
| | - Myzairah Hamdzah
- Institute of Environmental and Water Resource Management (IPASA), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru, Malaysia
| | - Mohd Fadhil Mohd Din
- Institute of Environmental and Water Resource Management (IPASA), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru, Malaysia
| | - Siti Aqlima Ahmad
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Khalilah Abdul Khalil
- Department of Biomolecular Sciences, Faculty of Applied Sciences, Universiti Teknologi MARA, 40150 Sec. 2, Shah Alam, Selangor, Malaysia
| | - Aznah Nor Anuar
- Institute of Environmental and Water Resource Management (IPASA), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru, Malaysia
| | - Zainura Zainon Noor
- Institute of Environmental and Water Resource Management (IPASA), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru, Malaysia
| | - Zaini Ujang
- Institute of Environmental and Water Resource Management (IPASA), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru, Malaysia
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16
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Chen FY, Liu YQ, Tay JH, Ning P. Rapid formation of nitrifying granules treating high-strength ammonium wastewater in a sequencing batch reactor. Appl Microbiol Biotechnol 2015; 99:4445-52. [PMID: 25573473 DOI: 10.1007/s00253-014-6363-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 12/22/2014] [Accepted: 12/24/2014] [Indexed: 11/26/2022]
Abstract
Short initial settling time and rapidly increased ammonium nitrogen loading were employed to cultivate nitrifying granular sludge treating inorganic wastewater with 1000 mg/L ammonium nitrogen. It was found that the nitrifying granule-dominant sludge was formed in a sequencing batch reactor (SBR) with influent ammonium concentration increased from 200 to 1000 mg N/L within 55 days. During the following 155-day operation period, nitrifying granules exhibited good performance with an ammonium removal efficiency of 99%. In the meantime, sludge volume index (SVI) decreased from 92 to 15 mL/g and the mean size of the nitrifying granules increased from 106 to 369 μm. Mixed liquor suspended solids (MLSS) decreased from the initial 6.4 to around 3 g/L during the granulation period and increased to over 10 g/L at the end of the operation. The long-term stability of nitrifying granules and the reactor performance were not negatively affected by inhibition from free ammonia (FA) and free nitrous acid (FNA) in this study. This makes the granule sludge technology promising in treating high-strength ammonium wastewater in practice.
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Affiliation(s)
- Fang-Yuan Chen
- College of Environmental Science and Engineering, Kunming University of Science and Technology, 282 Xuefu Road, 650093, Kunming, People's Republic of China
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17
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Long B, Yang CZ, Pu WH, Yang JK, Shi YF, Wang J, Bai J, Zhou XY, Jiang GS, Li CY, Liu FB. The stability of aerobic granular sludge treating municipal sludge deep dewatering filtrate in a bench scale sequencing batch reactor. BIORESOURCE TECHNOLOGY 2014; 169:244-250. [PMID: 25058300 DOI: 10.1016/j.biortech.2014.06.094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 06/27/2014] [Accepted: 06/27/2014] [Indexed: 06/03/2023]
Abstract
Inoculated with mature aerobic granular sludge in a sequencing batch reactor, gradually increasing the proportion of municipal sludge deep dewatering filtrate in influent, aerobic granular sludge was domesticated after 84 days and maintained its structure during the operation. The domesticated AGS was yellowish-brown, dense and irregular spherical shape, average size was 1.49 mm, water content and specific density were 98.13% and 1.0114, the SVI and settling velocity were 40 ml/g and 46.5m/h. After 38 days, NO3(-)-N accumulated obviously in the reactor as lack of carbon sources. When adding 1-3g solid CH3COONa at 4.5 and 5.5h of each cycle from the 57th day, the removal rate of TN rose to above 90% after 20 days, where effective COD removal and denitrification were realized in a single bioreactor. Finally, the removal rates of COD, TP, TN and NH4(+)-N were higher than 95%, 88%, 96% and 99%.
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Affiliation(s)
- Bei Long
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China
| | - Chang-Zhu Yang
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China.
| | - Wen-Hong Pu
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China
| | - Jia-Kuan Yang
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China.
| | - Ya-Fei Shi
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China
| | - Jing Wang
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China
| | - Jun Bai
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China
| | - Xuan-Yue Zhou
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China
| | - Guo-Sheng Jiang
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China
| | - Chun-Yang Li
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China
| | - Fu-Biao Liu
- College of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan 430074, PR China
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18
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Di Bella G, Torregrossa M. Simultaneous nitrogen and organic carbon removal in aerobic granular sludge reactors operated with high dissolved oxygen concentration. BIORESOURCE TECHNOLOGY 2013; 142:706-713. [PMID: 23751809 DOI: 10.1016/j.biortech.2013.05.060] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/14/2013] [Accepted: 05/16/2013] [Indexed: 06/02/2023]
Abstract
Simultaneous nitrification and denitrification (SND) together with organic removal in granules is usually carried out without Dissolved Oxygen (DO) concentration control, at "low DO" (with a DO<30-50% of the saturation value, about 3-4 mg/L) to promote anoxic conditions within the aggregates. These conditions can sometimes be in detrimental of the stability of the granules itself due to a lack of shear force. In this work, the authors achieved SND without oxygen control with big sized granules. More specifically, the paper presents a experimentation focused on the analysis of two Sequencing Batch Reactors (SBRs), in bench scale, working with different aerobic sludge granules, in terms of granule size, and high DO concentration, (with concentration varying from anoxic conditions, about DO ∼0 mg/L, to values close to those of saturation, >7-8 mg/L, during feast and famine conditions respectively). In particular, different strategies of cultivation and several organic and nitrogen loading rate have been applied, in order to evaluate the efficiencies in SND process without dissolved oxygen control. The results show that, even under conditions of high DO concentration, nitrogen and organic matter can be simultaneously removed, with efficiency >90%. Nevertheless, the biological conditions in the inner layer of the granule may change significantly between small and big granules, during the feast and famine periods. From point of view of granule stability, it is also interesting that with a particle size greater than 1.5mm, after the cultivation start-up, the granules are presented stable for a long period (about 100 days) and, despite the variations of operational conditions, the granules breaking was always negligible.
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Affiliation(s)
- Gaetano Di Bella
- Facoltà di Ingengeria e Architettura, Università degli Studi di Enna "Kore", Cittadella Universitaria, 94100 Enna, Italy.
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19
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Val del Río A, Morales N, Figueroa M, Mosquera-Corral A, Campos JL, Méndez R. Effects of the cycle distribution on the performance of SBRs with aerobic granular biomass. ENVIRONMENTAL TECHNOLOGY 2013; 34:1463-1472. [PMID: 24191480 DOI: 10.1080/09593330.2012.753470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The aerobic granular systems are mainly sequencing batch reactors where the biomass is submitted to feast-famine regimes to promote its aggregation in the form of granules. In these systems, different cycle distributions can be applied for the simultaneous removal of organic matter, nitrogen and phosphorus. In this work two strategies were followed in order to evaluate the effects of the cycle distribution. In the first experiment, the length of the operational cycle was decreased in order to maximize the treatment capacity and consequently the famine/feast ratio was also decreased. In the second experiment, an initial anoxic phase was implemented to improve nitrogen removal efficiency. The results obtained showed that to reduce the famine/feast ratio from 10 to 5 was possible by increasing the treated organic and nitrogen loading rates in the system to 33%, without affecting the removal efficiencies of organic matter (97%) and nitrogen (64%) and producing a slight detriment of the granules characteristics. On the other hand, the implementation of an anoxic phase of 30 min previous to the aerobic one with a pulse-fed mode increased the nitrogen removal of pig manure from 20 to 60%, while the cycle configuration comprising a continuous feeding simultaneous with an anoxic phase of 60 min did not enhance the nitrogen removal and even worsen the ammonia oxidation.
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Affiliation(s)
- A Val del Río
- Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, Santiago de Compostela, Spain.
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20
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Liu YQ, Tay JH. The competition between flocculent sludge and aerobic granules during the long-term operation period of granular sludge sequencing batch reactor. ENVIRONMENTAL TECHNOLOGY 2012; 33:2619-2626. [PMID: 23437662 DOI: 10.1080/09593330.2012.673011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The long-term operational stability of aerobic granular sludge reactor was investigated in this study. It was found that the fraction of flocculent sludge fluctuated from 5 to 35%, even with a settling time of less than 5 minutes and manual discharge of flocculent sludge during a steady state of more than 400 days. Although the microbial community structure of flocculent sludge was similar to that of granular sludge co-existing in the reactor, the specific growth rate, the observed biomass yield and the specific oxygen consumption rate of flocculent sludge were much higher than those of granular sludge with identical microbial community structures. Therefore, the presence offlocculent sludge in the granular sludge reactor is mainly because of the kinetic superiority of flocculent sludge over granular sludge, rather than microbial competition. Increasing mass transfer in the feast period or discharging excess flocculent sludge could enhance the growth of granular sludge and improve the stability of the long-term operation of the granular sludge reactor.
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Affiliation(s)
- Yong-Qiang Liu
- Institute of Environmental Science and Engineering, Nanyang Technological University, Singapore.
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21
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ORP slope and feast–famine strategy as the basis of the control of a granular sequencing batch reactor treating winery wastewater. Biochem Eng J 2012. [DOI: 10.1016/j.bej.2012.08.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Liu YQ, Moy B, Kong YH, Tay JH. Formation, physical characteristics and microbial community structure of aerobic granules in a pilot-scale sequencing batch reactor for real wastewater treatment. Enzyme Microb Technol 2010; 46:520-5. [DOI: 10.1016/j.enzmictec.2010.02.001] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 02/01/2010] [Accepted: 02/01/2010] [Indexed: 10/19/2022]
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23
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Biomass granulation in an aerobic:anaerobic-enhanced biological phosphorus removal process in a sequencing batch reactor with varying pH. J Ind Microbiol Biotechnol 2009; 36:885-93. [DOI: 10.1007/s10295-009-0566-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Accepted: 03/16/2009] [Indexed: 10/20/2022]
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24
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Li Y, Liu Y, Shen L, Chen F. DO diffusion profile in aerobic granule and its microbiological implications. Enzyme Microb Technol 2008. [DOI: 10.1016/j.enzmictec.2008.04.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Liu YQ, Wu WW, Tay JH, Wang JL. Formation and long-term stability of nitrifying granules in a sequencing batch reactor. BIORESOURCE TECHNOLOGY 2008; 99:3919-22. [PMID: 17826990 DOI: 10.1016/j.biortech.2007.07.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 07/18/2007] [Accepted: 07/18/2007] [Indexed: 05/17/2023]
Abstract
The formation and long-term stability of nitrifying granules in a sequencing batch reactor was investigated in this study. The results showed that nitrifying granules with a size of 240 microm and SVI of 40 ml g(-1) were formed on day 21 at a settling time of 10 min. Maintaining settling time at 15 min from day 57 to 183 did not affect the physical characteristics of sludge and the fraction of suspended floc in the sludge. In addition, nitrifying granules could tolerate the fluctuations of nitrogen loading rate from 0.72 to 1.8 g l(-1)d(-1) during 2 months without the change of physical characteristics. However, it was observed that complete nitrification to nitrate and partial nitrification to nitrite by sludge converted each other corresponding to the change of the influent NH4+-N concentration. Thus, an appropriate method is needed to maintain a stable complete nitrification or partial nitrification under the conditions with changing influent NH4+-N concentrations and nitrogen loading rates.
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Affiliation(s)
- Yong-Qiang Liu
- Institute of Environmental Science and Engineering, Nanyang Technological University, 18 Nanyang Drive, Singapore 637723, Singapore.
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26
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Liu YQ, Tay JH. Influence of starvation time on formation and stability of aerobic granules in sequencing batch reactors. BIORESOURCE TECHNOLOGY 2008; 99:980-5. [PMID: 17462886 DOI: 10.1016/j.biortech.2007.03.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 03/07/2007] [Accepted: 03/07/2007] [Indexed: 05/15/2023]
Abstract
Three sequencing batch reactors, R1, R2 and R3, with a 1.5-h, 4-h and 8-h cycle time, respectively, were used to cultivate aerobic granules with the same synthetic wastewater containing 1000 mg l(-1) COD. As the initial COD concentrations in the cycles were the same, three different cycle times led to three different starvation times in repeated cycles of the three reactors. It was found that 63 cycles were needed to form granules with the longest starvation time in R3 while it took 256 cycles in R1 with the shortest starvation time. However, as far as the formation time was concerned, granules were formed on day 16 with 1.5-h cycle time while on day 21 with 8-h cycle time, which indicated that a shorter cycle time with a shorter starvation time speeded up the granulation. This was mainly due to the stronger hydraulic selection pressure at shorter cycle time. However, it was found that granules formed with cycle time of 1.5h were unstable. Fluffy granules with poor settling ability were observed in R1 in the 4th month, which led to the collapse of R1 after 160-day of operation. Granules in R2 and R3 showed good stability during the long-term operation. Therefore, a reasonable starvation time was necessary to maintain the long-term stability of aerobic granules.
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Affiliation(s)
- Yong-Qiang Liu
- Environmental Engineering Research Centre, School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
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27
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Han Z, Wu W, Ding Y, Zhu J, Chen Y. Optimization of main factors associated with nitrogen removal in hybrid sludge sequencing batch reactor with step-feeding of swine wastewater. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2008; 43:161-170. [PMID: 18172808 DOI: 10.1080/10934520701781533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
To attain a high nitrogen removal efficiency and good sludge settleability in a step-fed sequencing batch reactor (SFSBR) treating swine wastewater, L(9)(3(4)) orthogonal experiments were carried out to optimize main factors associated with nitrogen removal, namely, the influent C/N ratio, feeding volume ratio, nitrogen loading rate and aeration intensity. Results showed that nitrogen loading rate contributed most for the build-up of NO(2)(-)-N, NO(3)(-)-N and NH(4)(+)-N in the effluent, while aeration intensity was the most important factor for net nitrogen removal efficiency based on the initial and final nitrogen concentrations in the SFSBR cycle. Additionally, the periodic starvation created by stepwise feeding was the major inducing force for granulation in the SFBSR process and the influent C/N ratio had a profound influence on sludge settleability and granular sludge stability in terms of sludge volume index (SVI) and the fraction of granular sludge with diameter over 0.5 mm (f(0.5 mm)), respectively. Considering the most and secondary important control factor for individual response index, the optimal operating condition for nitrogen removal of SFSBR treating swine wastewater was determined as A(3)B(3)C(1)D(2), i.e., influent C/N ratio 7.0 mg COD/mg NH(4)(+)-N, feeding volume ratio 3:1, nitrogen loading rate 0.026 g NH(4)(+)-N/gVSS . d and aeration intensity 4.2 L/m(3) . s, respectively. Under the optimal operating conditions, inorganic nitrogen concentration in the effluent, net nitrogen removal efficiency, SVI and f(0.5 mm) reached 21 mg/L, 72 %, 40.7 mL/g and 4.3 %, respectively.
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Affiliation(s)
- Zhiying Han
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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28
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Kim IS, Kim SM, Jang A. Characterization of aerobic granules by microbial density at different COD loading rates. BIORESOURCE TECHNOLOGY 2008; 99:18-25. [PMID: 17306977 DOI: 10.1016/j.biortech.2006.11.058] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 11/25/2006] [Accepted: 11/29/2006] [Indexed: 05/14/2023]
Abstract
Aerobic granules were cultivated under temporal alternating aerobic and anoxic conditions without the presence of a carrier material in a sequencing batch reactor (SBR) with a high column height/column diameter ratio. The reactor was operated for 6h per cycle (aerobic: 4.75 h, anoxic: 1.25 h). To determine a new parameter for the definition of aerobic granules, a protocol of 4,6-diamidino-2-phenylindole hydrochloride staining and fluorescence image processing was developed. The d(tm) analysis showed that the increase in the chemical oxygen demand (COD) loading rate promoted no more growth of the aerobic granules. It was inconsistent with the results of the analysis of the sludge volume index (SVI) value but matched well with the results of the COD and nitrogen removal of the SBR and the particle size distribution by LS-PSA. The optimum COD loading rate for aerobic granulation in the SBR was 2.52 kg/m(3)d. When d(tm) was correlated with the biomass concentration and the SVI value during the period of granule formation, d(tm) could be used as a more sensitive and accurate parameter for classifying aerobic granules and optimizing the operational conditions for aerobic granulation processes.
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Affiliation(s)
- In S Kim
- Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju, Republic of Korea.
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29
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Zhu L, Xu X, Luo W, Cao D, Yang Y. Formation and microbial community analysis of chloroanilines-degrading aerobic granules in the sequencing airlift bioreactor. J Appl Microbiol 2007; 104:152-60. [PMID: 17887986 DOI: 10.1111/j.1365-2672.2007.03548.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS This paper investigates a selection-based acclimation strategy for improving the performance and stability of aerobic granules at a high chloroanilines loading. METHODS AND RESULTS The experiments were conducted in a sequencing airlift bioreactor (SABR) to develop aerobic granules fed with chloroanilines (ClA). The evolution of aerobic granulation was monitored using image analysis and scanning electron microscopy, and PCR-DGGE analysis of microbial community was performed. The sludge granulation was apparently developed by decreased settling time and gradual increased ClA loading to 0.8 kg m(-3) day(-1). A steady-state performance of the granular SABR was reached at last, as evidenced by biomass concentration of 6.3 g l(-1) and constant ClA removal efficiency of 99.9%. The mature granules had a mean size of 1.55 mm, minimal settling velocity of 68.4 m h(-1), specific ClA degradation rate of 0.181 g gVSS(-1) day(-1). Phylogenetic analysis of aerobic ClA-degrading granules confirmed the dominance of beta-, gamma-Proteobacteria and Flavobacteria. CONCLUSIONS The chosen operating strategy involving step increase in ClA loading and enhancement of major selection pressures was successful in cultivating the aerobic ClA-degrading granules. SIGNIFICANCE AND IMPACT OF THE STUDY This research could be helpful for improving the stability of aerobic granules via optimizing operating conditions and developing economic feasible full-scale granular bioreactor.
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Affiliation(s)
- L Zhu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, China
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30
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Liu YQ, Tay JH. Influence of cycle time on kinetic behaviors of steady-state aerobic granules in sequencing batch reactors. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2007.04.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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31
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Liu YQ, Wu WW, Tay JH, Wang JL. Starvation is not a prerequisite for the formation of aerobic granules. Appl Microbiol Biotechnol 2007; 76:211-6. [PMID: 17457542 DOI: 10.1007/s00253-007-0979-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 03/27/2007] [Accepted: 03/28/2007] [Indexed: 10/23/2022]
Abstract
Activated sludge with sludge volume index (SVI)(30) of 77 ml g(-1) and SVI(30) of 433 ml g(-1) was inoculated to start up reactors R1 and R2, respectively. In both R1 and R2, cycle time of 1 h and the influent chemical oxygen demand (COD) concentrations of 1,000 mg l(-1) were employed. Initial settling time of 2 min resulted in the loss of a substantial amount of biomass as wash-out and high effluent COD concentrations within the first week of operation. This implied that there was no starvation phase in each cycle of R1 and R2 during the first week of operation. However, aerobic granules with a size above 400 mum formed by day 7. Thus, it was concluded that starvation was not a prerequisite for the formation of aerobic granules. When cycle time was 1 h, the instability of aerobic granules was observed. When cycle time was prolonged to 1.5 h and granular sludge of 200 ml was used to start up reactor R3, the reactor R3 reached steady state within 1 week. SVI, size, and the morphology of granular sludge in R3 remained stable during the 47-day operation, which indicated that prolonged starvation time had positive effects on the stability of aerobic granules.
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Affiliation(s)
- Yong-Qiang Liu
- Environmental Engineering Research Centre, School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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