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Kriswantoro JA, Chu CY, Chang TR, Pai HJ, Chang CK, Chiu YP. Comparison of thermal alkaline pretreatment and zinc acetate-catalyzed methanolysis (MtOH-ZnOAc) for anaerobic digestion of bioplastic waste. BIORESOURCE TECHNOLOGY 2023; 377:128959. [PMID: 36965583 DOI: 10.1016/j.biortech.2023.128959] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/20/2023] [Accepted: 03/22/2023] [Indexed: 06/18/2023]
Abstract
The aim of this work was to study the effect of thermal alkaline pretreatment and zinc acetate-catalyzed methanolysis (MtOH-ZnOAc) in biogas production from bioplastic in anaerobic digestion. The pretreated bioplastic with MtOH-ZnOAc performs efficient solubilization and produced 205.7 ± 6.9 mL/g CODadded, which is higher than thermal alkaline degradation. The mesophilic condition produces more than 79% higher biogas compared with the thermophilic condition with the diluted pretreated bioplastic by 30 times. The kinetic study was well fit the experimental data and showed the correlation between cumulative biogas, production rate, and lag phase with mono- and two-stage system in batch fermentation. The two-stage system produced 315.6 ± 7.7 mL/g CODadded which was higher 67.2 ± 2.02 than the mono-stage system. Methanosaetaceae predominates among the Archaea, which are primarily responsible for methanogenesis, showing a contribution to a higher biogas production rate.
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Affiliation(s)
- Jayen Aris Kriswantoro
- Ph.D. Program of Mechanical and Aeronautical Engineering, Feng Chia University, Taiwan; Institute of Green Products, Feng Chia University, Taiwan; School of Life Sciences and Technology, Institut Teknologi Bandung (ITB), Indonesia
| | - Chen-Yeon Chu
- Ph.D. Program of Mechanical and Aeronautical Engineering, Feng Chia University, Taiwan; Institute of Green Products, Feng Chia University, Taiwan; Institute of Atmospheric Pollution Research (IIA), CNR, Italy.
| | - Ting-Rui Chang
- Institute of Green Products, Feng Chia University, Taiwan; Department of Mechanical and Computer-Aided Engineering, Feng Chia University, Taiwan
| | - Hao-Jen Pai
- Institute of Green Products, Feng Chia University, Taiwan; Department of Mechanical and Computer-Aided Engineering, Feng Chia University, Taiwan
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2
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Huang H, Ekama G, Deng YF, Chen GH, Wu D. Identifying the mechanisms of sludge reduction in the sulfidogenic oxic-settling anaerobic (SOSA) process: Side-stream sulfidogenesis-intensified sludge decay and mainstream extended aeration. WATER RESEARCH 2021; 189:116608. [PMID: 33189974 DOI: 10.1016/j.watres.2020.116608] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/03/2020] [Accepted: 11/05/2020] [Indexed: 06/11/2023]
Abstract
An energy-/cost-efficient and environment-friendly in-situ sludge reduction process, called the sulfidogenic oxic-settling anaerobic (SOSA) was developed recently. However, the underpinning mechanism of sludge reduction by the SOSA process remains elusive. This paper investigated the possible mechanisms of sludge reduction through biomass cultivation in three lab-scale experimental systems: one anoxic-oxic CAS process with a long sludge retention time (SRT) and extended aeration (EAO) process, and two EAO-based in-situ sludge reduction processes, i.e., the conventional oxic-settling anaerobic (COSA) process and the new SOSA process. These three comparative biosystems were operated with identical influent and reactor configurations as well as the same biomass concentrations and SRTs (approximately 5 g/L and 46 days, respectively), and the sludge interchange ratios (between the CAS and side-stream reactors) in COSA and SOSA were both 10% per day. Three systems all achieved high organic (>93%) and total nitrogen (TN) (>74%) removal efficiencies. SOSA produced 29% and 20% less sludge than EAO and COSA, respectively, simultaneously consumed 14% and 8% more oxygen than EAO and COSA, indicating that the sludge reduction in SOSA was not only caused by EAO-based aerobic digestion in the mainstream and conventional anaerobic reactions in the side-stream, but more importantly due to the bioaugmentation of sulfidogenesis. The roles of sulfidogenesis were further studied in batch tests, and the key findings were as follows: i) the SOSA biomass had a faster endogenous decay rate (0.097 d-1) than that of the COSA biomass (0.045 d-1), and ii) sulfidogenesis accelerated anaerobic solubilization, hydrolysis, acidogenesis and acetogenesis by 2.3 - 3.1 times, 6 - 22 %, 22 - 60% and 6 - 22%, respectively. Overall, the mechanisms of sludge reduction in SOSA were unraveled in this study which will help promote its full-scale application in future.
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Affiliation(s)
- Hao Huang
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China; Wastewater Technology Lab, Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology, Guangdong, China
| | - George Ekama
- Water Research Group, Department of Civil Engineering, University of Cape Town, Cape Town, South Africa
| | - Yang-Fan Deng
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China; Wastewater Technology Lab, Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology, Guangdong, China
| | - Guang-Hao Chen
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China; Wastewater Technology Lab, Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology, Guangdong, China
| | - Di Wu
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China; Wastewater Technology Lab, Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology, Guangdong, China.
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3
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Sun LP, Lin YJ, Shi CY, Wang SQ, Luo WX, Wang M. Effects of interchange ratio on sludge reduction and microbial community structures in an anaerobic/anoxic/oxic process with combined anaerobic side-stream reactor. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 81:1250-1263. [PMID: 32597411 DOI: 10.2166/wst.2020.223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Oxic-settling-anaerobic (OSA) process is effective in minimizing sludge production, by inserting an anaerobic side-stream reactor (ASSR) in the recycling bypass. Interchange ratio (IR), the quantity ratio of sludge entering the ASSR to the sludge in the main stream reactors, is one of the most important parameters for OSA process. In the present study, a laboratory-scale anaerobic/anoxic/oxic (A2/O) process combined with an ASSR (A2/O-ASSR) was operated for 366 days in parallel with a conventional A2/O process to investigate the effects of IR on sludge reduction. IR was assigned values of 5%, 8%, 10%, and 15%, and the A2/O-ASSR process achieved 14.0%, 16.0%, 24.1%, and 13.7% of sludge reduction, respectively. At the optimum IR of 10%, high through-put sequencing analysis showed that the microbes responsible for pollutant removal and ubiquitous in wastewater treatment remained predominant in the two systems, and slow-growing microbes related to hydrolysis, nitrogen and phosphorus removal increased in the A2/O-ASSR process, which probably played a key role in sludge reduction. 40.6-58.6% of sludge reduction was caused by sludge decay in the ASSR. The tiny amount of extracellular polymeric substance released in the A2/O-ASSR process was subthreshold to cause remarkable sludge reduction.
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Affiliation(s)
- L P Sun
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China E-mail: ; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, China
| | - Y J Lin
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China E-mail:
| | - C Y Shi
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China E-mail:
| | - S Q Wang
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China E-mail: ; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, China
| | - W X Luo
- Foshan Water Group, Guangdong, Foshan, 528000, China
| | - M Wang
- Guangzhou Yuekang Environmental Engineering Co., Ltd, Guangdong, Guangzhou 510275, China
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4
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Guo JS, Fang F, Yan P, Chen YP. Sludge reduction based on microbial metabolism for sustainable wastewater treatment. BIORESOURCE TECHNOLOGY 2020; 297:122506. [PMID: 31812600 DOI: 10.1016/j.biortech.2019.122506] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/21/2019] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
Sludge reduction via microbial metabolism does not require extra energy and resource inputs and thus merits attention as an alternative approach for sustainable wastewater treatment. This review presents a summary and analysis of the existing literatures on sludge reduction based on microbial metabolism, as well as interprets these sludge reduction mechanisms using bacterial thermodynamics and stoichiometry. Future efforts should be directed toward using advanced analytical techniques to further reveal sludge reduction mechanisms. The feasibility of coupling sludge reduction and nutrient removal by microorganism metabolism needs to be further evaluated to minimize the effect of sludge reduction on nutrient removal. A comprehensive life cycle assessment of sludge reduction strategies is recommended to effectively confirm their sustainability. Full-scale research is needed to verify the results obtained from bench- and pilot-scale experiments. This review presents the future opportunities and challenges for sludge reduction based on microbial metabolism in the excess sludge disposal.
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Affiliation(s)
- Jin-Song Guo
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Fang Fang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Peng Yan
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
| | - You-Peng Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
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5
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Huang H, Ekama GA, Biswal BK, Dai J, Jiang F, Chen GH, Wu D. A new sulfidogenic oxic-settling anaerobic (SOSA) process: The effects of sulfur-cycle bioaugmentation on the operational performance, sludge properties and microbial communities. WATER RESEARCH 2019; 162:30-42. [PMID: 31254884 DOI: 10.1016/j.watres.2019.06.051] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 05/05/2023]
Abstract
In-situ sludge reduction can be achieved by inserting an anaerobic side-stream reactor in the sludge return line of the conventional activated sludge (CAS) process. This modified oxic-settling-anaerobic (OSA) process can reduce sludge production by 30-50% through feast-fast alternating conditions. This paper proposes a new bioprocess called the sulfidogenic oxic-settling anaerobic (SOSA) process with OSA configuration and the addition of sulfate in side-stream reactor. The new bioprocess augments the conventional anaerobic/anoxic/aerobic feast-fast bioconversions with sulfur biochemical transformations (i.e. sulfate reduction and sulfur-oxidizing autotrophic denitrification). A lab-scale SOSA process was operated for 260 days in parallel with the anoxic/oxic (AO) CAS process and the conventional OSA process as control systems. Based on the experimental results, the feasibility of the new SOSA process was evaluated, and the effects of sulfur bioaugmentation on the effluent quality, sludge reduction, sludge physico-chemical properties and microbial communities were examined. The SOSA process i) removed 98% of the organics (chemical oxygen demand, COD) and 99% of the ammonia present with a lower observed sludge yield (0.204 g TSS/g CODremoved) than those of the OSA and AO processes (0.292 and 0.473 g TSS/g CODremoved respectively), ii) denitrified 18% and 6% more nitrogen to dinitrogen gas than did the CAS and OSA processes respectively, iii) produced sludge with improved settleability and dewaterability, iv) encouraged sludge decomposition with greater destruction of extracellular polymeric substances and v) enriched sulfur-cycle related and hydrolytic/fermentative bacteria. The possible mechanisms of sulfur augmentation and limitations of the present study are also discussed.
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Affiliation(s)
- Hao Huang
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong; HKUST Shenzhen Research Institute, Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology, Guangdong, China
| | - George A Ekama
- Water Research Group, Department of Civil Engineering, University of Cape Town, Cape Town, South Africa
| | - Basanta K Biswal
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong
| | - Ji Dai
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong
| | - Feng Jiang
- Guangdong Provincial Engineering Technology Research Center for Wastewater Management and Treatment, School of Chemistry & Environment, South China Normal University, Guangdong, China
| | - Guang-Hao Chen
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong; HKUST Shenzhen Research Institute, Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology, Guangdong, China
| | - Di Wu
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong; HKUST Shenzhen Research Institute, Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology, Guangdong, China.
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6
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Karlikanovaite-Balikci A, Yagci N. Evaluation of sludge reduction in an oxic-settling-anoxic system operated with step feeding regime for nutrient removal and fed with real domestic wastewater. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 243:385-392. [PMID: 31103684 DOI: 10.1016/j.jenvman.2019.05.042] [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: 12/24/2018] [Revised: 05/01/2019] [Accepted: 05/10/2019] [Indexed: 06/09/2023]
Abstract
In the present study, the effect of sludge age was evaluated for simultaneous sludge reduction and nitrogen removal in an oxic-settling-anoxic (OSA) system fed with real domestic wastewater. Three laboratory-scale systems utilizing aerobic and anoxic zones and step feeding regime were operated for sludge age of 13, 17 and 20 days in the main reactors. A significant influence of sludge age on the sludge reduction was observed compared to conventional activated sludge systems (CAS). The greater corresponding sludge reduction was achieved as 58% operated at interchange ratio of 7.7% (1/13) in the side-stream reactor, while others revealed 37% and 35%, where interchange ratios were 5.9 (1/17) and 5.0% (1/20), respectively. In both CAS and OSA systems, high removal efficiencies of organic matter and nitrogen were achieved using real domestic wastewater. The results indicate that intermittently aerated OSA systems could accomplish less sludge production and higher nitrogen removal (up to 85%) simultaneously. Thus, it is suggested that interchange ratio of around 8% is more optimized level, which is a little lower than that of proposed and applied in most studies in the literature, which would possibly be more cost-effective.
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Affiliation(s)
- Agne Karlikanovaite-Balikci
- Faculty of Civil Engineering, Environmental Engineering Department, Istanbul Technical University, 34469, Istanbul, Turkey.
| | - Nevin Yagci
- Faculty of Civil Engineering, Environmental Engineering Department, Istanbul Technical University, 34469, Istanbul, Turkey.
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7
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Hossain MI, Paparini A, Cord-Ruwisch R. Direct oxygen uptake from air by novel glycogen accumulating organism dominated biofilm minimizes excess sludge production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 640-641:80-88. [PMID: 29857323 DOI: 10.1016/j.scitotenv.2018.05.292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/23/2018] [Accepted: 05/23/2018] [Indexed: 06/08/2023]
Abstract
The cost associated with treatment and disposal of excess sludge produced is one of the greatest operational expenses in wastewater treatment plants. In this study, we quantify and explain greatly reduced excess sludge production in the novel glycogen accumulating organism (GAO) dominated drained biofilm system previously shown to be capable of extremely energy efficient removal of organic carbon (biological oxygen demand or BOD) from wastewater. The average excess sludge production rate was 0.05 g VSS g-1 BOD (acetate) removed, which is about 9-times lower than that of comparative studies using the same acetate based synthetic wastewater. The substantially lower sludge yield was attributed to a number of features such as the high oxygen consumption facilitated by direct oxygen uptake from air, high biomass content (21.41 g VSS L-1 of reactor), the predominance of the GAO (Candidatus competibacter) with a low growth yield and the overwhelming presence of the predatory protozoa (Tetramitus) in the biofilm. Overall, the combination of low-energy requirement for air supply (no compressed air supply) and the low excess sludge production rate, could make this novel "GAO drained biofilm" process one of the most economical ways of biological organic carbon removal from wastewater.
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Affiliation(s)
- Md Iqbal Hossain
- School of Engineering and Information Technology, Murdoch University, 90 South Street, Murdoch 6150, Western Australia, Australia
| | - Andrea Paparini
- School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch 6150, Western Australia, Australia
| | - Ralf Cord-Ruwisch
- School of Engineering and Information Technology, Murdoch University, 90 South Street, Murdoch 6150, Western Australia, Australia.
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8
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Na JH, Nam DH, Ko BG, Lee CY, Kang KH. Reduced sludge production in a membrane bioreactor by uncoupling metabolism and its effect on phosphorus accumulation in the biomass. ENVIRONMENTAL TECHNOLOGY 2017; 38:3007-3015. [PMID: 28110608 DOI: 10.1080/09593330.2017.1285964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 01/18/2017] [Indexed: 06/06/2023]
Abstract
UNLABELLED Due to its limited recycling or reuse, treatment and disposal of excess waste activated sludge has been a major challenge. As a preemptive method, therefore, uncoupling metabolism for reduced sludge production has been investigated recently. In this study, we operated a pilot-scale A2O-membrane bioreactor (MBR) system incorporating an anaerobic sludge holding tank (SHT) in a sludge recycling line to induce uncoupling metabolism, and investigated sludge production and treatment efficiency. After operation for ≥1 year, the Yobs value was estimated to be 0.041 g mixed liquor suspended solid (MLSS)/g chemical oxygen demand with 198.7 days of solids retention time (SRT). This Yobs value was markedly lower than those reported previously. Since MBR can be operated with a relatively high MLSS and prolonged SRT, the greatest reduction was achieved by combination with uncoupling metabolism. Phosphate fractionation experiments of the MLSS from the pilot MBR suggested the total phosphate content of microorganisms was 47.0 mg P/g mixed liquor volatile suspended solid; 83% higher than that of the activated sludge process and 49% higher than that of the conventional A2O process. Of the increased phosphate contents, that of the acid-insoluble polyphosphate (AISP) fraction was greatest, suggesting that growth inhibition by uncoupling metabolism stimulates AISP synthesis, which can be utilized under growth-limiting conditions. ABBREVIATIONS AISP: acid-insoluble polyphosphate; ASP: acid-soluble polyphosphate; BNR: biological nutrients removal; EPS: extracellular polymeric substance; LMH: L/m2 h; MBR: membrane bioreactor; OST: oxic-settling-anaerobic; PAO: phosphate accumulation organism; PCA: perchloric acid; SBR: sequencing batch reactor; SHT: sludge holding tank; SRT: solids retention time; TN: total nitrogen; TP: total phosphate; WAS: waste activated sludge.
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Affiliation(s)
- Ji-Hun Na
- a Technology R&D Institute, Daelim Industrial Co., Ltd. , Seoul , Korea
- b Department of Environmental Engineering , University of Seoul , Seoul , Korea
| | - Duck-Hyun Nam
- a Technology R&D Institute, Daelim Industrial Co., Ltd. , Seoul , Korea
| | - Byeong-Gon Ko
- a Technology R&D Institute, Daelim Industrial Co., Ltd. , Seoul , Korea
- c Department of Civil Engineering , The University of Suwon , Suwon , Gyeonggi-do , Korea
| | - Chae-Young Lee
- c Department of Civil Engineering , The University of Suwon , Suwon , Gyeonggi-do , Korea
| | - Ki-Hoon Kang
- a Technology R&D Institute, Daelim Industrial Co., Ltd. , Seoul , Korea
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9
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Yan P, Guo JS, Wang J, Ji FY, Zhang CC, Chen YP, Shen Y. Enhanced excess sludge hydrolysis and acidification in an activated sludge side-stream reactor process with single-stage sludge alkaline treatment: a pilot scale study. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:22761-22770. [PMID: 27562811 DOI: 10.1007/s11356-016-7490-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 08/17/2016] [Indexed: 06/06/2023]
Abstract
A pilot-scale side-stream reactor process with single-stage sludge alkaline treatment was employed to systematically investigate characteristics of excess sludge hydrolysis and acidification with alkaline treatment and evaluate feasibility of recovering a carbon source (C-source) from excess sludge to enhance nutrient removal at ambient temperature. The resulting C-source and volatile fatty acid specific yields reached 349.19 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) d-1 and 121.3 mg COD/g VSS d-1, respectively, the process had excellent C-source recovery potential. The propionic-to-acetic acid ratio of the recovered C-source was 3.0 times that in the influent, which beneficially enhanced biological phosphorus removal. Large populations and varieties of hydrolytic acid producing bacteria cooperated with alkaline treatment to accelerate sludge hydrolysis and acidification. Physicochemical characteristics indicated that recovered C-source was derived primarily from extracellular polymeric substances hydrolysis rather than from cells disruption during alkaline treatment. This study showed that excess sludge as carbon source was successfully recycled by alkaline treatment in the process.
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Affiliation(s)
- Peng Yan
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China
- Key Laboratory of Reservoir Aquatic Environment, Chinese Academy of Science, Chongqing, 400714, China
| | - Jin-Song Guo
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China
- Key Laboratory of Reservoir Aquatic Environment, Chinese Academy of Science, Chongqing, 400714, China
| | - Jing Wang
- Chongqing Jianzhu College, Chongqing, 400072, China
| | - Fang-Ying Ji
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing, 400045, China
| | - Cheng-Cheng Zhang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing, 400045, China
| | - You-Peng Chen
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
- Key Laboratory of Reservoir Aquatic Environment, Chinese Academy of Science, Chongqing, 400714, China.
| | - Yu Shen
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
- Key Laboratory of Reservoir Aquatic Environment, Chinese Academy of Science, Chongqing, 400714, China.
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10
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Zhang AN, Mao Y, Zhang T. Development of Quantitative Real-time PCR Assays for Different Clades of "Candidatus Accumulibacter". Sci Rep 2016; 6:23993. [PMID: 27142574 PMCID: PMC4855135 DOI: 10.1038/srep23993] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 03/18/2016] [Indexed: 11/27/2022] Open
Abstract
We designed novel quantitative real-time polymerase chain reaction (qPCR) primers for the polyphosphate kinase 1 (ppk1) gene, targeting eight individual “Candidatus Accumulibacter” (referred to as Accumulibacter) clades. An evaluation of primer sets was conducted regarding the coverage, specificity, and PCR efficiency. (i) All primer sets were designed to cover all available sequences of the target clade. (ii) The phylogenetic analysis of the sequences retrieved from the qPCR products by each primer set demonstrated a high level of specificity. (iii) All calibration curves presented high PCR efficiencies in the range of 85–112% (R2 = 0.962–0.998). In addition, the possible interference of non-target amplicons was individually examined using the qPCR assay for 13 Accumulibacter clades, which were either undetected or showed negligible detection. With the primers designed by other research groups, a highly selective and sensitive qPCR-based method was developed to quantify all Accumulibacter clades, with the exception of Clade IE, in one assay, which enables more comprehensive insights into the community dynamics. The applicability to environmental samples was demonstrated by profiling the Accumulibacter clades in activated sludge samples of nine full-scale wastewater treatment plants.
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Affiliation(s)
- An Ni Zhang
- Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Yanping Mao
- Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Tong Zhang
- Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
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11
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Yang S, Guo W, Chen Y, Peng S, Du J, Zheng H, Feng X, Ren N. Simultaneous in-situ sludge reduction and nutrient removal in an A(2)MO-M system: Performances, mechanisms, and modeling with an extended ASM2d model. WATER RESEARCH 2016; 88:524-537. [PMID: 26524657 DOI: 10.1016/j.watres.2015.09.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 08/05/2015] [Accepted: 09/28/2015] [Indexed: 06/05/2023]
Abstract
Among the existing in-situ sludge reduction processes, the oxic-settling-anaerobic (OSA) process is of particular interest because it has shown significant sludge reduction with several advantages. However, an ideal process for practical application must simultaneously incorporate effluent quality with sludge reduction. In this study, an improved OSA system, the stage-aerated anaerobic, anoxic, micro-aerobic, and oxic system combining a micro-aerobic starvation tank (abbreviated as A(2)MO-M system) was developed. Compared with OSA3# (hydraulic retention time (HRT) of 12 h), the A(2)MO-M2# system with optimized HRT of 9 h yielded almost 16.3% less sludge. The average total nitrogen (87.3%) and total phosphorus (91.9%) removal efficiencies in A(2)MO-M2# were 20.6 and 42.2% higher than those in OSA3#. Investigation of the mechanisms of sludge reduction revealed that, except for the main factors of energy uncoupling metabolism (16.7%) and sludge decay (21.2%), enrichment of slow-growing bacteria and lysis-cryptic growth metabolism analyzed by high-throughput 454 pyrosequencing were shown to contribute to sludge reduction in the A(2)MO-M system. On the basis of effluent organic matters (EfOM) measurements, soluble microbial products (SMP) were the major components in EfOM; and different reduction-oxidation (redox) potentials controlled in the OSA and A(2)MO-M systems led to different SMP formation mechanisms. To explore the mechanism and kinetics of SMP formation under different redox potentials, three new components (SUAP, SBAP, and XEPS) were integrated in an extended ASM2d model. Experimental and modeling results revealed that biomass-associated products (BAP) supported a substantial population of SMP that were quite sensitive to different redox potentials. The extended ASM2d model further illustrated that more BAP produced in the alternating anaerobic and aerobic conditions in the OSA system adversely affected its effluent quality.
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Affiliation(s)
- Shanshan Yang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
| | - Yidi Chen
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Simai Peng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Juanshan Du
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Heshan Zheng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Xiaochi Feng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China.
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Habermacher J, Benetti AD, Derlon N, Morgenroth E. The effect of different aeration conditions in activated sludge--Side-stream system on sludge production, sludge degradation rates, active biomass and extracellular polymeric substances. WATER RESEARCH 2015; 85:46-56. [PMID: 26295938 DOI: 10.1016/j.watres.2015.08.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 07/16/2015] [Accepted: 08/01/2015] [Indexed: 06/04/2023]
Abstract
On-site minimization of excess sludge production is a relevant strategy for the operation of small-scale and decentralized wastewater treatment plants. In the study, we evaluated the potential of activated sludge systems equipped with side-stream reactors (SSRs). This study especially focused on how the sequential exposure of sludge to different aeration conditions in the side-stream reactors influences the overall degradation of sludge and of its specific fractions (active biomass, extracellular polymeric substances (EPS), EPS proteins, EPS carbohydrates). We found that increasing the solid retention time from 25 to 40 and 80 days enhanced sludge degradation for all aeration conditions tested in the side-stream reactor. Also, the highest specific degradation rate and in turn the lowest sludge production were achieved when maintaining aerobic conditions in the side-stream reactors. The different sludge fractions in terms of active biomass (quantified based on adenosine tri-phosphate (ATP) measurements), EPS proteins and EPS carbohydrates were quantified before and after passage through the SSR. The relative amounts of active biomass and EPS to volatile suspended solids (VSS) did not changed when exposed to different aeration conditions in the SSRs, which indicates that long SRT and starvation in the SSRs did not promote the degradation of a specific sludge fraction. Overall, our study helps to better understand mechanisms of enhanced sludge degradation in systems operated at long SRTs.
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Affiliation(s)
- Jonathan Habermacher
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland; Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Antonio Domingues Benetti
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland; Universidade Federal do Rio Grande do Sul, CNPq, Av. Bento Goncalves 9500, Porto Alegre, Brazil
| | - Nicolas Derlon
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland; Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland.
| | - Eberhard Morgenroth
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland; Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
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Huang P, Goel R. Response of a sludge-minimizing lab-scale BNR reactor when the operation is changed to real primary effluent from synthetic wastewater. WATER RESEARCH 2015; 81:301-310. [PMID: 26086148 DOI: 10.1016/j.watres.2015.04.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 04/21/2015] [Accepted: 04/23/2015] [Indexed: 06/04/2023]
Abstract
The activated sludge process is the most widely used treatment method for municipal wastewater. However, the excessive amount of biomass generated during the process is a major drawback. Earlier studies using the activated sludge process running in a biomass fasting and feasting mode demonstrated both nutrient removal and a minimization of biomass production. However, these studies were conducted using synthetic wastewater. In this study, we report findings from a lab-scale sludge-minimizing biological nutrient removing (BNR) reactor when its operation was changed from synthetic to real wastewater (primary effluent). Two lab-scale sequencing batch reactors, one in sludge minimization mode (hereafter called modified-SBR), and the other in conventional activated sludge mode (referred as control-SBR), were operated for more than 300 days. Both reactors were started and operated with synthetic feed. Gradually the feed to both reactors was changed to 100% primary effluent collected from a local full-scale wastewater treatment plant. Irrespective of the feed composition, more than 98% NH3-N removal was recorded in both SBRs. However, while 89% of the total dissolved phosphorus was removed from the 100% synthetic feed, only 80% of the total dissolved phosphorus was removed from the 100% primary effluent in both SBRs. The overall observed sludge reduction in the modified-SBR as compared to the control-SBR also decreased from 65% to 39% when the feed was changed from 100% synthetic to 100% primary effluent. The specific oxygen uptake rate for the modified-SBR was 80% higher than that for the control-SBR when the SBRs were fed with primary effluent wastewater. The modified-SBR showed a greater diversity of ammonia-oxidizing bacteria (AOBs) with synthetic wastewater as well as during the transition period than the control-SBR. Yet when the reactors were running on 100% real wastewater, only Nitrosomonas europaea/eutropha were identified in both SBRs. The nitrite-oxidizing bacterial community and the polyphosphate accumulating organisms (PAOs) responded in a similar way in both SBRs.
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Affiliation(s)
- Pei Huang
- Department of Civil & Environmental Engineering, University of Utah, Salt Lake City, United States
| | - Ramesh Goel
- Department of Civil & Environmental Engineering, University of Utah, Salt Lake City, United States.
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