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Le HQ, Duong CC, Chang HM, Nguyen NC, Chien IC, Ngo HH, Chen SS. Innovative hyper-thermophilic aerobic submerged membrane distillation bioreactor for wastewater reclamation. CHEMOSPHERE 2024; 362:142743. [PMID: 38950740 DOI: 10.1016/j.chemosphere.2024.142743] [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: 04/10/2024] [Revised: 06/05/2024] [Accepted: 06/29/2024] [Indexed: 07/03/2024]
Abstract
For the first time, a hyper-thermophilic aerobic (>60 °C) bioreactor has been integrated with direct submerged membrane distillation (MD), highlighting its potential as an advanced wastewater treatment solution. The hyper-thermophilic aerobic bioreactor, operating up to 65 °C, is tailored for high organic removal, while MD efficiently produces clean water. Throughout the study, high removal rates of 99.5% for organic matter, 96.4% for ammonia, and 100% for phosphorus underscored the impressive adaptability of microorganisms to challenging hyper-thermophilic conditions and a successful combination with the MD process. Despite the extreme temperatures and substantial salinity accumulation reaching up to 12,532 μS/cm, the biomass of microorganisms increased by 1.6 times over a 92-day period, representing their remarkable resilience. The distillation flux ranged from 6.15 LMH to 8.25 LMH, benefiting from the temperature gradient in the hyper-thermophilic setting and the design of the tubular submerged MD membrane module. The system also excels in pH control, utilizing fewer alkali and nutritional resources than conventional systems. Meiothermus, Firmicutes, and Bacteroidetes, the three dominant species, played a crucial role, showcasing their significance in adapting to high salinity and decomposing organic matter.
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Affiliation(s)
- Huy Quang Le
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No.1, Sec. 3, Zhongxiao E. Rd, Taipei, 10608, Taiwan; Faculty of Chemistry and Environment, Dalat University, 01 Phu Dong Thien Vuong Street, Da Lat City, 66000, Viet Nam
| | - Chinh Cong Duong
- Southern Institute of Water Resources Research, 658 Vo Van Kiet Street, District 5, Ho Chi Minh City, 700000, Viet Nam
| | - Hau-Ming Chang
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No.1, Sec. 3, Zhongxiao E. Rd, Taipei, 10608, Taiwan
| | - Nguyen Cong Nguyen
- Faculty of Chemistry and Environment, Dalat University, 01 Phu Dong Thien Vuong Street, Da Lat City, 66000, Viet Nam
| | - I-Chieh Chien
- Department of Water Resources and Environmental Engineering, Tamkang University, New Taipei City, 251301, Taiwan
| | - Huu Hao Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Shiao-Shing Chen
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No.1, Sec. 3, Zhongxiao E. Rd, Taipei, 10608, Taiwan.
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2
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Liu Q, Li Y, Sun Y, Xie K, Zeng Q, Hao Y, Yang Q, Pu Y, Shi S, Gong Z. Deterioration of sludge characteristics and promotion of antibiotic resistance genes spread with the co-existing of polyvinylchloride microplastics and tetracycline in the sequencing batch reactor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167544. [PMID: 37797771 DOI: 10.1016/j.scitotenv.2023.167544] [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: 07/31/2023] [Revised: 09/11/2023] [Accepted: 09/30/2023] [Indexed: 10/07/2023]
Abstract
With the continuous increase in microplastics (MPs) and tetracycline (TC) entering wastewater treatment plants (WWTPs) along with sewage, the co-existence of MPs and TC in the biological treatment of wastewater has attracted extensive attention. This study investigated the effect of 1 mg/L polyvinyl chloride (PVC) MPs and 100 ng/L TC co-existing on sequencing batch reactors (SBRs) (S2) treating phenol wastewater in contrast to the control with TC alone (S1). The phenol removal efficiency was significantly inhibited by the co-existence of PVC MPs and TC. Sludge characteristics were also distinctively influenced. The decreased zone sludge velocity (ZSV) and increased sludge volume index (SVI) indicated that the combined effect of PVC MPs and TC deteriorated sludge settleability, which had positive and negative linear correlations with extracellular polymeric substances (EPS) content and the protein (PN)/polysaccharide (PS) ratio, respectively. Moreover, the decreased and increased relative abundances of potential phenol-degraders and antibiotic resistance gene (ARG) carriers may elucidate the inhibition of phenol removal and promotion of ARGs propagation with the co-occurrence of PVC MPs and TC. In addition, the enhanced potential ARGs hosts, loss of the EPS protective effect, and increased membrane permeability induced by reactive oxygen species (ROS) jointly promoted ARGs dissemination in the co-existence of PVC MPs and TC. Notably, the co-occurrence of ARGs and mobile genetic element (MGEs) indicated that the co-existence of PVC MPs and TC promoted the spread of some transposase-associated ARGs mediated by horizontal gene transfer (HGT).
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Affiliation(s)
- Qiangwei Liu
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China
| | - Yuxin Li
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China
| | - Yanan Sun
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China
| | - Kunpeng Xie
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China
| | - Qianzhi Zeng
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China
| | - Yiming Hao
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China
| | - Qing Yang
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China
| | - Yunhong Pu
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China
| | - Shengnan Shi
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China..
| | - Zheng Gong
- School of Life Sciences, Liaoning Normal University; Key Laboratory of Plant Biotechnology of Liaoning Province, Dalian, Liaoning 116081, PR China..
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3
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Xie Y, Zhu Y, Yang J, Zhang G, Tian S, Lian J, Dong S. Effect of ultrasound on the stability of partial nitrification: Under the interference of aeration rate. ULTRASONICS SONOCHEMISTRY 2023; 100:106642. [PMID: 37838531 PMCID: PMC10653954 DOI: 10.1016/j.ultsonch.2023.106642] [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: 03/12/2023] [Revised: 09/23/2023] [Accepted: 10/07/2023] [Indexed: 10/16/2023]
Abstract
The fluctuation of dissolved oxygen is one of the primary cause of disruptions to the consistent operation of partial nitrification, and the level of dissolved oxygen is mainly controlled by the aeration rate. This study investigated the influence of ultrasonic treatment on the stability of partial nitrification of activated sludge under different aeration conditions. After being treated with ultrasound (energy density = 0.20 W·mL-1, treatment time = 10 min), partial nitrification process operated stably for 67 days, with the nitrite accumulation rate above 83.89 %. The effluent contained 42.50 mg·L-1 of nitrite, much higher than the control reactor (0.30 mg·L-1). The gap between the specific ammonia and nitrite oxidation rates widened continuously as the aeration rate increased, and nitrite-oxidizing bacteria activity did not recover even under conditions with a very high oxygen content. Further analysis showed that ultrasonic treatment had obvious stripping effect on excess extracellular polymeric substances (EPS), especially loosely bound EPS and protein. Additionally, long-term ultrasonic treatment promoted the enrichment of Nitrosomonas and strongly inhibited Nitrotoga. Based on these findings, it appears that under conditions of high aeration rate, ultrasound effectively suppress the recovery of Nitrotoga activity and improve the stability of partial nitrification.
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Affiliation(s)
- Ying Xie
- Jiangxi Provincial Key Laboratory of Environmental Geotechnology and Engineering Disaster Control, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Yichun Zhu
- Jiangxi Provincial Key Laboratory of Environmental Geotechnology and Engineering Disaster Control, Jiangxi University of Science and Technology, Ganzhou 341000, China.
| | - Jieyuan Yang
- Jiangxi Provincial Key Laboratory of Environmental Geotechnology and Engineering Disaster Control, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Guangming Zhang
- School of Energy & Environmental Engineering, Hebei University of Technology, Tianjin 300401, China
| | - Shuai Tian
- Jiangxi Provincial Key Laboratory of Environmental Geotechnology and Engineering Disaster Control, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Junfeng Lian
- Jiangxi Provincial Key Laboratory of Environmental Geotechnology and Engineering Disaster Control, Jiangxi University of Science and Technology, Ganzhou 341000, China
| | - Shanyan Dong
- Jiangxi Provincial Key Laboratory of Environmental Geotechnology and Engineering Disaster Control, Jiangxi University of Science and Technology, Ganzhou 341000, China
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4
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Du Z, Zhao P, Fu Q, Wang Q, Hu A, Zhang W, Wang D. Biostimulants in dissolved organic matters recovered from anaerobic digestion sludge with alkali-hydrothermal treatment: Nontarget identification by ultrahigh-resolution mass spectrometry. ENVIRONMENT INTERNATIONAL 2023; 173:107813. [PMID: 36805157 DOI: 10.1016/j.envint.2023.107813] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Recovering high-value biomaterials from anaerobic digestion sludge (ADS) has attracted considerable attention. However, the molecular features and biological effects of abundant dissolved organic matters (DOMs) in ADS are still unclear, which limits the efficient recycling and application of these bioproducts. This study investigated the molecular composition and transformation of DOMs recovered from ADS through a mild-temperature alkali-hydrothermal treatment (AHT) with ultrahigh-resolution mass spectrometry and energy spectroscopy, and the fertilizing effects of DOMs were evaluated by rice hydroponics. The results indicated that AHT processes significantly promoted the solubilization and release of DOMs from ADS, where most of DOMs molecules remained unchanged and mainly consisted of N-containing compounds with 1-3 N atoms, featuring aromatic or N-heterocyclic rings. Furthermore, AHT processes at pH of 9-10 induced the hydrolysis of partial protein-like substances in DOMs, which was accompanied by formation of heterocyclic-N compounds. Under AHT at pH of 11-12, protein-like and heterocyclic-N substances were increasingly decomposed into amino-N compounds containing 1 or 5 N atoms, while numerous oxygenated aromatic substances with phytotoxicity were degraded and removed from DOMs. Rice hydroponic test verified that ADS-derived DOMs recovered by AHT process at pH of 12 exhibited the highest bioactivity for rice growth, which was attributed to the abundance of amino compounds and humic substances. This study proposed a novel process for the recovery of high-quality liquid organic fertilizer from ADS through AHT process, which can further enrich the technical options available for the safe utilization of sludge resources.
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Affiliation(s)
- Zhengliang Du
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Peipei Zhao
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Qinglong Fu
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Qiandi Wang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Aibin Hu
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Weijun Zhang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Dongsheng Wang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
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Sun X, Bian D, Wang F, Ai S, Liu W, Bian W, Liu W. Study on the inhibition of sludge bulking in A 2/O coupled system at low temperature by segmented inlet water mode. ENVIRONMENTAL TECHNOLOGY 2023; 44:853-863. [PMID: 34559585 DOI: 10.1080/09593330.2021.1985624] [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: 07/03/2021] [Accepted: 09/18/2021] [Indexed: 06/13/2023]
Abstract
This study aimed to propose a segmented influent method to inhibit sludge bulking. The sludge bulking phenomenon was observed in a A2/O coupled system treating municipal wastewater under low temperature (15 ± 0.5)°C. Adopting the segmented inlet water process, the distribution ratio of the inlet flow in the anaerobic zone and the aerobic zone were 2:1 and 1:1, the sludge bulking phenomenon was suppressed. The sludge loading rate (F/M) analysis showed that the F/M of the anaerobic zone with single-point inflow was only 0.15 kg COD·(kg MLSS·d)-1, which was prone to induce sludge bulking. However, the F/M concentration gradient of the system under segmented inlet water conditions was obvious, which could inhibit the sludge bulking caused by low F/M. The effluent removal results showed that the system had high removal rates of COD, NH4+-N, TN, and TP at a flow distribution ratio of 2:1, with average removal rates of 88.85% ± 2.94%, 91.26% ± 6.68%, 76.60% ± 5.60%, and 96.80% ± 2.17%, respectively. This study confirmed that the segment inlet method inhibited sludge bulking, while the flow distribution ratio of 2:1 also ensured efficient pollutant removal capacity of the system.
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Affiliation(s)
- Xuejian Sun
- Changchun Institute of Technology, Changchun, People's Republic of China
- Jilin Key Laboratory of Urban Sewage Treatment, Changchun, People's Republic of China
| | - Dejun Bian
- Changchun Institute of Technology, Changchun, People's Republic of China
- Jilin Key Laboratory of Urban Sewage Treatment, Changchun, People's Republic of China
| | - Fan Wang
- Changchun Institute of Technology, Changchun, People's Republic of China
- Jilin Key Laboratory of Urban Sewage Treatment, Changchun, People's Republic of China
| | - Shengshu Ai
- Changchun Institute of Technology, Changchun, People's Republic of China
- Jilin Key Laboratory of Urban Sewage Treatment, Changchun, People's Republic of China
| | - Wenai Liu
- Changchun Institute of Technology, Changchun, People's Republic of China
- Jilin Key Laboratory of Urban Sewage Treatment, Changchun, People's Republic of China
| | - Wei Bian
- Changchun Institute of Technology, Changchun, People's Republic of China
- Jilin Key Laboratory of Urban Sewage Treatment, Changchun, People's Republic of China
| | - Wanqi Liu
- Changchun Institute of Technology, Changchun, People's Republic of China
- Jilin Key Laboratory of Urban Sewage Treatment, Changchun, People's Republic of China
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6
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Figueroa A, Hadengue B, Leitão JP, Blumensaat F. A framework for modelling in-sewer thermal-hydraulic dynamic anomalies driven by stormwater runoff and seasonal effects. WATER RESEARCH 2023; 229:119492. [PMID: 36549185 DOI: 10.1016/j.watres.2022.119492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 11/27/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Rain-induced surface runoff and seasons lead to short- to medium-term anomalies in combined storm- and wastewater flows and temperatures, and influence treatment processes in wastewater resource recovery facilities (WRRF). Additionally, the implementation of decentralized heat recovery (HR) technologies for energy reuse in buildings affect energy-related processes across the urban water cycle and WRRFs heat inflows. However, quantitative insights on thermal-hydraulic dynamics in sewers at network scale and across different scales are very rare. To enhance the understanding of thermal-hydraulic dynamics and the water-energy nexus across the urban water cycle we present a modular framework that couples thermal-hydraulic processes: i) on the surface, ii) in the public sewer network, iii) in households (including in-building HR systems), and iv) in lateral connections. We validate the proposed framework using field measurements at full network scale, present modelling results of extended time periods to illustrate the effect of seasons and precipitation events simultaneously, and quantify the impact of decentralized HR devices on thermal-hydraulics. Simulation results suggest that the presented framework can predict temperature dynamics consistently all year long including short- to long-term variability of in-sewer temperature. The study provides quantitative evidence that the impact of household HR technologies on WRRF inflow heat budgets is reduced by approximately 20% during wet-weather periods in comparison to dry-weather conditions. The presented framework has potential to support multiple research initiatives that will improve the understanding of the water-energy nexus, pollutant dispersion and degradation, and support maintenance campaigns at network scale.
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Affiliation(s)
- Alejandro Figueroa
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland.
| | - Bruno Hadengue
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - João P Leitão
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Frank Blumensaat
- Landesdirektion Sachsen, Federal Ministry of Internal Affairs of Saxony, Dresden, Deutschland
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7
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Gao J, Li L, Yuan S, Chen S, Dong B. The neglected effects of polysaccharide transformation on sludge humification during anaerobic digestion with thermal hydrolysis pretreatment. WATER RESEARCH 2022; 226:119249. [PMID: 36323201 DOI: 10.1016/j.watres.2022.119249] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/03/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
Humus accumulation during sludge stabilization is attracting increasing attention because of its land use potential. This study investigated the effects of thermal hydrolysis pretreatment (THP) on sludge humification and the related regulatory mechanisms during anaerobic digestion (AD). The sludge subjected to AD with THP at 160 °C (AnD-160) exhibited 7.3% and 8.5% higher total extractable carbon (TEC) and humic acid carbon (HAC) concentrations than the unpretreated sludge, respectively, while the sludge subjected to AD with THP at 180 °C (AnD-180) exhibited 1.4% and 7.0% lower concentrations. Humification of AnD-160 and AnD-180 were enhanced and inhibited, respectively. THP influenced sludge humification during AD through both intracellular polyphenol synthesis and extracellular humus condensation pathways related to polysaccharide metabolism. The 160 °C-pretreated sludge exhibited higher polysaccharide availability (more soluble polysaccharides and reducing sugars) than the other samples and thus had more active intracellular polyphenol metabolism during AD. The polyphenol accumulation stimulated the synthesis of related condensation enzymes (polyphenol oxidase and quinone oxidoreductases), facilitating extracellular HA production during AD. However, THP at 180 °C resulted in the highest production of melanoidins with CO-C heterocycles through C = O and CH sites of polysaccharides (778.46 vs. 193.87 R.U. nm2-mL/g for the unpretreated sample). This heterocyclization decreased the polysaccharide availability and inhibited intracellular polyphenol synthesis, consequently inhibiting condensation enzymes supply and extracellular HA production during AD. Overall, this study highlights the crucial but neglected role of polysaccharides in sludge humification during AD: the availability of polysaccharides affected by their occurrence state and molecular structure could determine the humification, which can be regulated by THP at different temperature.
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Affiliation(s)
- Jun Gao
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Lei Li
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Shijie Yuan
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Sisi Chen
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Bin Dong
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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Modelling the performance of an integrated fixed-film activated sludge (IFAS) system: a systematic approach to automated calibration. Sci Rep 2022; 12:9416. [PMID: 35676437 PMCID: PMC9177546 DOI: 10.1038/s41598-022-13779-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/13/2022] [Indexed: 11/08/2022] Open
Abstract
IFAS systems are inherently complex due to the hybrid use of both suspended and attached bacterial colonies for the purpose of pollutant degradation as part of wastewater treatment. This poses challenges when attempting to represent these systems mathematically due to the vast number of parameters involved. Besides becoming convoluted, large effort will be incurred during model calibration. This paper demonstrates a systematic approach to calibration of an IFAS process model that incorporates two sensitivity analyses to identify influential parameters and detect collinearity from a subset of 68 kinetic and stoichiometric parameters, and the use of the Nelder–Mead optimization algorithm to estimate the required values of these parameters. The model considers the removal of three critical pollutants including biochemical oxygen demand (BOD), total nitrogen (TN) and total suspended solids (TSS). Results from the sensitivity analyses identified four parameters that were the primary influence on the model. The model was found to be most sensitive to the two stoichiometric parameters including aerobic heterotrophic yield on soluble substrate whose total effects were responsible for 92.4% of the model’s BOD output sensitivity and 92.8% of the model’s TSS output sensitivity. The anoxic heterotrophic yield on soluble substrate was observed to be responsible for 54.3% of the model’s TN output sensitivity. To a lesser extent the two kinetic parameters, aerobic heterotrophic decay rate and reduction factor for denitrification on nitrite, were responsible for only 8.0% and 13.1% of the model’s BOD and TN output sensitivities respectively. Parameter estimation identified the need for only minor adjustments to default values in order to achieve sufficient accuracy of simulation with deviation from observed data to be only ± 3.6 mg/L, ± 1.3 mg/L, and ± 9.5 mg/L for BOD, TN and TSS respectively. Validation showed the model was limited in its capacity to predict system behaviour under extreme dissolved oxygen stress.
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Melo A, Quintelas C, Ferreira EC, Mesquita DP. The Role of Extracellular Polymeric Substances in Micropollutant Removal. FRONTIERS IN CHEMICAL ENGINEERING 2022. [DOI: 10.3389/fceng.2022.778469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In biological wastewater treatment (WWT), microorganisms live and grow held together by a slime matrix comprised of extracellular polymeric substances (EPS), forming a three-dimensional microbial structure of aggregates (flocs or granules) and by chemical binding forces. Furthermore, microscopic observations showed that microbial cells within the flocs were cross linked with EPS, forming a network of polymers with pores and channels. The EPS are typically composed of organic substances such as polysaccharides (PS), proteins (PNs), humic acid substances (HAS), nucleic acids, and lipids. It has been established that EPS play an essential role in aggregate flocculation, settling, and dewatering. Moreover, in the presence of toxic substances, such as pharmaceutical compounds and pesticides, EPS form a protective layer for the aggregated biomass against environmental disturbances that might play an important role in the transport and transformation of micropollutants. Some researchers indicated that there is an increase in EPS concentration under toxic conditions, which can induce an increase in the size of microbial aggregates. In this contribution, we critically review the available information on the impact of micropollutants on microbial EPS production and the relationship between EPS and microbial aggregate structure. Also, a general definition, composition, and factors that affect EPS production are presented.
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10
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Hu D, Liu L, Liu W, Yu L, Dong J, Han F, Wang H, Chen Z, Ge H, Jiang B, Wang X, Cui Y, Zhang W, Zhang Y, Liu S, Zhao L. Improvement of sludge characteristics and mitigation of membrane fouling in the treatment of pesticide wastewater by electrochemical anaerobic membrane bioreactor. WATER RESEARCH 2022; 213:118153. [PMID: 35152135 DOI: 10.1016/j.watres.2022.118153] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/29/2021] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
Electrochemical anaerobic membrane bioreactor attracted attention due to stable treatment quality with low footprint, and draw solute has significant effect on the sludge characteristics and membrane fouling performance. In this pilot-scale study, an electrochemical anaerobic membrane bioreactor (E-AnMBR) was proposed for treating pesticide wastewater at different hydraulic retention times (HRTs), demonstrating that E-AnMBR was superior on improvement of sludge characteristics and mitigation of membrane fouling, compared with the conventional anaerobic membrane bioreactor (C-AnMBR). E-AnMBR reduced sludge yield by 41.2 ± 6.7% and the SVI was significantly decreased by 32.5±13.8%. The accumulation of VFA in E-AnMBR was slighter than that of C-AnMBR, and the minimum average VFA was 255±6 mg/L. The methane yield of E-AnMBR (0.22-0.29 L CH4/g CODremoved) was 1.2-1.4 times than that of C-AnMBR. The EPS contents in suspended and attached sludge of E-AnMBR were significantly reduced by 41.8 ± 3.3% and 77.4 ± 14.5% than that of C-AnMBR, respectively. These results suggested that E-AnMBR has lower sludge disposal pressure, higher stability and methane recovery potential. Not only that, E-AnMBR successfully reduced membrane resistance, delaying the fouling rate by 31.0-38.5%. Finally, the linear relationship between EPS characteristics and membrane pollution was determined.
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Affiliation(s)
- Dongxue Hu
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Lixue Liu
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Wenyu Liu
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Liqiang Yu
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Jian Dong
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Fei Han
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Hongcheng Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen, 518055, China.
| | - Zhaobo Chen
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China.
| | - Hui Ge
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Bei Jiang
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Xin Wang
- College of Environment Science and Engineering, Nankai Universty, 94 Weijin Road, Tianjin 300071, China
| | - Yubo Cui
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Wanjun Zhang
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Ying Zhang
- School of Resources and Environmental Science, Northeast Agricultural University, 59 Mucai Street, HarBin 150030, China
| | - Shuchen Liu
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
| | - Longmei Zhao
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian 116600, China; College of Environment and Resources, Dalian Minzu University, 18 Liaohe West Road, Dalian 116600, China
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11
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Dominic D, Baidurah S. Recent Developments in Biological Processing Technology for Palm Oil Mill Effluent Treatment-A Review. BIOLOGY 2022; 11:biology11040525. [PMID: 35453724 PMCID: PMC9031994 DOI: 10.3390/biology11040525] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary Palm oil mill effluent (POME) requires treatment prior to discharge to the environment. Biological processing technology is highly preferable due to its advantages of environmentally friendliness, cost effectiveness, and practicality. These methods utilized various designs and modifications of bioreactors fostering effective fermentation technology in the presence of fungi, bacteria, microalgae, and a consortium of microorganisms. This review highlights the recent biological processing technology for POME treatment as a resource utilization. Abstract POME is the most voluminous waste generated from palm oil milling activities. The discharge of POME into the environment without any treatment processing could inflict an undesirable hazard to humans and the environment due to its high amount of toxins, organic, and inorganic materials. The treatment of POME prior to discharge into the environment is utmost required to protect the liability for human health and the environment. Biological treatments are preferable due to eco-friendly attributes that are technically and economically feasible. The goal of this review article is to highlight the current state of development in the biological processing technologies for POME treatment. These biological processing technologies are conducted in the presence of fungi, bacteria, microalgae, and a consortium of microorganisms. Numerous microbes are listed to identify the most efficient strain by monitoring the BOD, COD, working volume of the reactor, and treatment time. The most effective processing technology for POME treatment uses an upflow anaerobic sludge blanket reactor with the COD value of 99%, hydraulic retention time of 7.2 days, and a working volume of 4.7 litres. Biological processing technologies are mooted as an efficient and sustainable management practice of POME waste.
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12
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Zhang M, Leung KT, Lin H, Liao B. Membrane fouling in a microalgal-bacterial membrane photobioreactor: Effects of P-availability controlled by N:P ratio. CHEMOSPHERE 2021; 282:131015. [PMID: 34090001 DOI: 10.1016/j.chemosphere.2021.131015] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/11/2021] [Accepted: 05/26/2021] [Indexed: 06/12/2023]
Abstract
Microalgal-bacterial membrane photobioreactor (MB-MPBR) is a promising technology to simultaneously remove organics and nutrients from wastewater. However, membrane fouling in MB-MPBR was seldom studied. In this study, potential effects of P-availability on biomass properties and membrane fouling in MB-MPBR were investigated. Under a nitrogen sufficient condition, a lower N:P ratio of 3.9:1 (P-rich) caused more severe membrane fouling. The dominant fouling mechanism was cake layer formation. Serial characterization showed a smaller particle size distribution (PSD), more free microalgae and significantly different surface composition of microalgal-bacterial flocs at N:P ratio of 3.9:1 compared with that of 9.7:1. The variations on PSD and surface composition were fully consistent with that of filtration resistance and thus considered as the primary contributors to the different fouling performance. The above results suggested that controlling microalgae/bacteria consortium in a good ratio by optimizing operating conditions is the key event for membrane fouling control in MB-MPBRs.
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Affiliation(s)
- Meijia Zhang
- Biotechnoloy Research Program, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada; Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada; Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada; College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, PR China
| | - Kam-Tin Leung
- Biotechnoloy Research Program, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada; Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada
| | - Hongjun Lin
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, PR China
| | - Baoqiang Liao
- Biotechnoloy Research Program, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada; Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada.
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13
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Melo A, Costa J, Quintelas C, Ferreira EC, Mesquita DP. Effect of ibuprofen on extracellular polymeric substances (EPS) production and composition, and assessment of microbial structure by quantitative image analysis. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 293:112852. [PMID: 34091137 DOI: 10.1016/j.jenvman.2021.112852] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/16/2021] [Accepted: 05/05/2021] [Indexed: 06/12/2023]
Abstract
A Sequencing Batch Reactor (SBR) with activated sludge was operated with synthetic wastewater containing ibuprofen (IBU) to investigate the biomass stress-responses under long-term IBU exposure. There were 3 different phases: phase I as the control without IBU for 56 days, phase II (40 days), and phase III (60 days) containing IBU at 10 and 5 mg L-1 each. The overall performance of the SBR as well as the extracellular polymeric substances (EPS) in terms of polysaccharides, proteins, and humic acid substances were estimated. Morphological parameters of microbial aggregates in the presence of IBU (phase II and phase III) were assessed by quantitative image analysis (QIA). Removal efficiencies of chemical oxygen demand (COD) and ammonium (NH4+) were significantly reduced by IBU. Loosely bound EPS (LB-EPS) decreased during phase II and phase III, and tightly bound EPS (TB-EPS) was slightly higher in phase II than phase I. TB-EPS proteins were greater in phase II, perhaps to protect microbial cells from IBU exposure. These findings provided insight into both activated sludge stress-responses and EPS composition under long-term IBU exposure. Spearman correlation showed that EPS and morphological parameters significantly affected sludge settleability and flocculation. QIA also proved to be a powerful technique in investigating dysfunctions in activated sludge under IBU exposure.
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Affiliation(s)
- António Melo
- CEB - Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Joana Costa
- CEB - Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Cristina Quintelas
- CEB - Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Eugénio C Ferreira
- CEB - Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Daniela P Mesquita
- CEB - Centre of Biological Engineering, Universidade Do Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
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14
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Banti DC, Mitrakas M, Samaras P. Membrane Fouling Controlled by Adjustment of Biological Treatment Parameters in Step-Aerating MBR. MEMBRANES 2021; 11:membranes11080553. [PMID: 34436316 PMCID: PMC8399131 DOI: 10.3390/membranes11080553] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 11/16/2022]
Abstract
A promising solution for membrane fouling reduction in membrane bioreactors (MBRs) could be the adjustment of operating parameters of the MBR, such as hydraulic retention time (HRT), food/microorganisms (F/M) loading and dissolved oxygen (DO) concentration, aiming to modify the sludge morphology to the direction of improvement of the membrane filtration. In this work, these parameters were investigated in a step-aerating pilot MBR that treated municipal wastewater, in order to control the filamentous population. When F/M loading in the first aeration tank (AT1) was ≤0.65 ± 0.2 g COD/g MLSS/d at 20 ± 3 °C, DO = 2.5 ± 0.1 mg/L and HRT = 1.6 h, the filamentous bacteria were controlled effectively at a moderate filament index of 1.5-3. The moderate population of filamentous bacteria improved the membrane performance, leading to low transmembrane pressure (TMP) at values ≤ 2 kPa for a great period, while at the control MBR the TMP gradually increased reaching 14 kPa. Soluble microbial products (SMP), were also maintained at low concentrations, contributing additionally to the reduction of ΤΜP. Finally, the step-aerating MBR process and the selected imposed operating conditions of HRT, F/M and DO improved the MBR performance in terms of fouling control, facilitating its future wider application.
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Affiliation(s)
- Dimitra C. Banti
- Laboratory of Technologies of Environmental Protection and Utilization of Food By-Products, Department of Food Science and Technology, International Hellenic University, GR-57400 Thessaloniki, Greece;
- Correspondence:
| | - Manassis Mitrakas
- Laboratory of Analytical Chemistry, Department of Chemical Engineering, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece;
| | - Petros Samaras
- Laboratory of Technologies of Environmental Protection and Utilization of Food By-Products, Department of Food Science and Technology, International Hellenic University, GR-57400 Thessaloniki, Greece;
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15
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Yang Y, Hu Y, Duan A, Wang XC, Hao Ngo H, Li YY. Characterization of preconcentrated domestic wastewater toward efficient bioenergy recovery: Applying size fractionation, chemical composition and biomethane potential assay. BIORESOURCE TECHNOLOGY 2021; 319:124144. [PMID: 32979595 DOI: 10.1016/j.biortech.2020.124144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/12/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Domestic wastewater (DWW) can be preconcentrated to facilitate energy recovery via anaerobic digestion (AD), following the concept of "carbon capture-anaerobic conversion-bioenergy utilization." Herein, real DWW and preconcentrated domestic wastewater (PDWW) were both subject to particle size fractionation (0.45-2000 μm). DWW is a type of low-strength wastewater (average COD of 440.26 mg/L), wherein 60% of the COD is attributed to the substances with particle size greater than 0.45 μm. Proteins, polysaccharides, and lipids are the major DWW components. PDWW with a high COD concentration of 2125.89 ± 273.71 mg/L was obtained by the dynamic membrane filtration (DMF) process. PDWW shows larger proportions of settleable and suspended fractions, and accounted for 63.4% and 33.8% of the particle size distribution, and 52.4% and 32.2% of the COD, respectively. The acceptable biomethane potential of 262.52 ± 11.86 mL CH4/g COD of PDWW indicates bioenergy recovery is feasible based on DWW preconcentration and AD.
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Affiliation(s)
- Yuan Yang
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, PR China
| | - Yisong Hu
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, PR China; Department of Civil and Environmental Engineering, Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
| | - Ao Duan
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, PR China
| | - Xiaochang C Wang
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; Key Lab of Environmental Engineering, Shaanxi Province, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, PR China
| | - Huu Hao Ngo
- International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, PR China; Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Yu-You Li
- Department of Civil and Environmental Engineering, Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
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16
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Yan X, Zheng S, Yang J, Ma J, Han Y, Feng J, Su X, Sun J. Effects of hydrodynamic shear stress on sludge properties, N 2O generation, and microbial community structure during activated sludge process. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 274:111215. [PMID: 32814212 DOI: 10.1016/j.jenvman.2020.111215] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/06/2020] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
Sludge properties are critical to the treatment performance and potentially correlate with nitrous oxide (N2O) generation during activated sludge processes. The hydrodynamic shear stress induced by aeration has a significant influence on sludge properties and is inevitable for wastewater treatment plants (WWTPs). In this study, the effects of aerobic induced hydrodynamic shear stress on sludge properties, N2O generation, and microbial community structure were investigated using three parallel sequencing batch reactors (SBRs) with identical dissolved oxygen (DO) concentrations. Results showed that with a shear stress increase from 1.5 × 10-2 N/m2 to 5.0 × 10-2 N/m2, the COD and NH4+-N removal rates were enhanced from 89.4% to 94.0% and from 93.9% to 98.0%, respectively, while the TN removal rate decreased from 66.0% to 56.5%. Settleability of the activated sludge flocs (ASFs) also increased with the enhancement of shear stress, due to variation in sludge properties including particle size, regularity, compactibility, and EPS (extracellular polymeric substances) composition. The increase in shear stress promoted oxygen diffusion within the ASFs and mitigated NO2--N accumulation, leading to a decrease in the N2O-N conversion rate from (4.8 ± 0.3)% to (2.2 ± 0.6)% (based on TN removal). Microbial analysis results showed that the functional bacteria involved in the biological nitrogen removal was closely related with shear stress. The increase in shear stress favored the enrichment of nitrite oxidizing bacteria (NOB) while suppressed the accumulation of ammonia-oxidizing bacteria (AOB) and denitrifying bacteria (DNB).
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Affiliation(s)
- Xu Yan
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China.
| | - Shikan Zheng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jie Yang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jiahui Ma
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Yunping Han
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Jinglan Feng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Xianfa Su
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jianhui Sun
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
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17
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High-Loaded Bioflocculation Membrane Reactor of Novel Structure for Organic Matter Recovery from Sewage: Effect of Dissolved Oxygen on Bioflocculation and Membrane Fouling. SUSTAINABILITY 2020. [DOI: 10.3390/su12187385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study, a new structure of high-load membrane bioreactor (HLB-MR) was used to treat urban sewage, and the effects of dissolved oxygen (DO) on biological flocculation and membrane pollution were researched. Parallel comparative experiments were used to investigate the concentration and recovery efficiency of organic matter, the bioflocculation effect, the content of extracellular polymer substance (EPS), the concentration of metal cations, membrane fouling status and microbial community structure in the reactors under the conditions of 1–2 and 6–8 mg/L. The flocculation efficiency of HLB-MR was 83% and 89% when DO was 1–2 and 6–8 mg/L, respectively. Under DO of 6–8 mg/L, the contents of bound and free EPS in the HLB-MR were 15.64 mg/gVSS and 8.71 mg/L, respectively. These values were significantly higher than those obtained when DO was 1–2 mg/L (11.83 mg/gVSS and 6.56 mg/L, respectively). Moreover, the concentrations of magnesium and aluminum in the concentrate of the HLB-MR were significantly higher when DO was 6–8 mg/L. Under higher DO concentration, there would be more EPS combined with metal cations, and thus fixed in the sludge substrate, the process of which promoted the bioflocculation. Changes in the transmembrane pressure (TMP) showed that the HLB-MR at a higher DO concentration suffered more serious membrane fouling. The species difference between the supernatant and precipitate was more significant under a higher DO concentration. The plankton species in the supernatant, e.g., norank_p__Saccharibacteria, norank_f__Neisseriaceae, and 12up, were likely to exacerbate membrane fouling. However, the species in the precipitate like Trichococcus, Ornithinibacter, and norank_f__Saprospiraceae may have a positive effect on bioflocculation.
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18
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Li ZH, Guo Y, Hang ZY, Zhang TY, Yu HQ. Simultaneous evaluation of bioactivity and settleability of activated sludge using fractal dimension as an intermediate variable. WATER RESEARCH 2020; 178:115834. [PMID: 32339865 DOI: 10.1016/j.watres.2020.115834] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 03/25/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
Bioactivity and settleability of activated sludge are essential for the operation of activated sludge systems in wastewater treatment. In this work, the fractal dimension of sludge image is proposed as a tool to evaluate these two factors. The specific endogenous respiration rate (SOURe) and the specific quasi-endogenous respiration rate (SOURq) are found to be more dependent on the 3D structure of sludge than the specific total respiration rate (SOURt). The relationship between the fractal structure and bioactivity suggests that the bioactivity governs the acceptable upper bound of the fractal dimension (Df), as at its theoretical maximum of 2.0, the non-porous compact flocs are predominant. The settleability or the biomass concentration determines the acceptable lower bound of Df, as at its theoretical minimum of 1.0, the free-swimming microbes are predominant. Our data reveal that the activated sludge has an acceptable fractal dimension Df in a range of 1.07-1.68. In practice, the fractal dimension should be controlled at a reasonable value as there is a trade-off between the bioactivity and physical structure to achieve better performance. A decrease or increase in the fractal dimension can serve as a signal for the change of the operational status, and this is further elucidated from the perspective of settling tanks using state point analysis. Compared with respirogram measurement, measuring fractal dimension is a complex process and its online implementation is challenging. Also, the measured value varies with the methods used. In addition, the difference in their theoretical values depends on the homogeneity of the sludge structure. Since the fractal dimension Df reflects both bioactivity and settleability of the sludge but is difficult to measure, in this work a relationship between Df and the easily measurable respirogram is established, and a method using the respirogram as a proxy of Df is proposed to control the bioactivity and settleability simultaneously. This respiration-based method is able to simultaneously control aeration and settling tanks, and could serve as an efficient tool for the management of wastewater treatment plants.
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Affiliation(s)
- Zhi-Hua Li
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Yao Guo
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Zhen-Yu Hang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Tian-Yu Zhang
- Department of Mathematical Sciences, Montana State University, Bozeman, MT, 59717-2400, USA
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, 230026, China.
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19
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Shen Y, Huang DM, Chen YP, Yan P, Gao X. New insight into filamentous sludge bulking during wastewater treatment: Surface characteristics and thermodynamics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 712:135795. [PMID: 31866048 DOI: 10.1016/j.scitotenv.2019.135795] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/22/2019] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
Although there have been many studies on filamentary bulking of activated sludge, it has been revealed that there is still a gap in the microscopic mechanism of filamentary bulking. In this study, the surface characteristics and thermodynamics of sludge floc were investigated to reveal the mechanism of filamentous sludge bulking. The results showed that the EPS content gradually decreased from 71.09 mg/g VSS to 40.00 mg/g VSS and the protein (PN) content of the EPS significantly decreased from 64.10 mg/g VSS to 35.85 mg/g VSS during sludge bulking. The variation in the EPS and its components led to a decrease in the relative hydrophobicity of sludge and an increase in surface negative charge; then, deterioration of the flocculation setteability of sludge flocs occurred. The electric double layer (WR) was the main force determining the aggregation of sludge during sludge bulking. The total energy of the interaction (WT) increased during sludge bulking, which led to an increase in the difficulty of sludge accumulation. This study is useful for understanding the filamentous bulking of sludge within an activated sludge process.
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Affiliation(s)
- Yu Shen
- National Research Base of Intelligent Manufacturing Service, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China; Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd., Chongqing 400067, China
| | - Dong-Mei Huang
- National Research Base of Intelligent Manufacturing Service, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China; Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd., Chongqing 400067, China
| | - You-Peng Chen
- 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.
| | - Xu Gao
- National Research Base of Intelligent Manufacturing Service, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China
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20
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Suresh A, Pan C, Ng WJ. Sodium azide inhibition of microbial activities and impact on sludge floc destabilization. CHEMOSPHERE 2020; 244:125452. [PMID: 31821925 DOI: 10.1016/j.chemosphere.2019.125452] [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: 06/26/2019] [Revised: 11/19/2019] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
Absence of sludge deflocculation under prolonged (24 h or longer) conditions with dissolved oxygen (DO) less than 0.5 mg L⁻1 was recently reported. The reduced aerobic microbial activity, was speculated, had been compensated by the activity of other bacterial (i.e. facultative) communities. To assess such a compensation mechanism and to better evaluate impact of overall microbial activity on the flocculation process, SBR sludge samples were inhibited by using sodium azide under various DO conditions. Sludge deflocculated only in the presence of sodium azide, regardless of DO conditions. This was linked to sodium azide's inhibitory effects on the microbes as indicated by the reduced ammonium and DOC removals. Extracellular potassium level in the mixed liquor of azide spiked samples also indicated simultaneous cell lysis. Fluorescence excitation emission matrix (FEEM) analysis of the extracted bound EPS and fluorescence quenching based interaction studies indicated sodium azide had interacted with the EPS components, and especially with the bound EPS proteins. The impact of such interactions on reduced floc stability needs consideration. This study confirmed the importance of overall microbial activity in the biological flocculation process and the role of bacterial communities, other than the aerobes, in mitigating deflocculation under low DO conditions.
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Affiliation(s)
- Akshaykumar Suresh
- Nanyang Environment & Water Research Institute, Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Chaozhi Pan
- Environmental Bio-innovations Group (EBiG), School of Civil and Environmental Engineering, Nanyang Technological University, N1-01a-29, 50 Nanyang Ave, 639798, Singapore
| | - Wun Jern Ng
- Environmental Bio-innovations Group (EBiG), School of Civil and Environmental Engineering, Nanyang Technological University, N1-01a-29, 50 Nanyang Ave, 639798, Singapore.
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21
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Feng Q, Ge R, Sun Y, Fang F, Luo J, Xue Z, Cao J, Li M. Revealing hydrodynamic effects on flocculation performance and surface properties of sludge by comparing aeration and stirring systems via computational fluid dynamics aided calculation. WATER RESEARCH 2020; 172:115500. [PMID: 31986396 DOI: 10.1016/j.watres.2020.115500] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 12/29/2019] [Accepted: 01/09/2020] [Indexed: 06/10/2023]
Abstract
The effects of aeration and stirring systems on the physical properties of sludge were analyzed using a computational fluid dynamics (CFD) model. The aims of this study were to (1) compare the effects of aeration and stirring on sludge properties using the same turbulent mixing intensity, and (2) to reveal the relationship between sludge properties and hydrodynamic indicators to determine how hydrodynamic conditions influence sludge flocculation. Mixing experiments with stirring and aeration were carried out in 2-L beakers with the average velocity gradient (G) set to 90, 190, or 280 s-1. The sludge flocculation performance, zeta potential, and Gibbs free energy (ΔG) were analyzed and the flow velocity, turbulence energy, turbulence dissipation rate, and Kolmogorov microscale were calculated as hydrodynamic parameters. The average flow velocity and the turbulence dissipation rate were obviously higher in the stirring system than in the aeration system at the same G. However, the turbulence energy and Kolmogorov microscale in the aeration system were much higher than those in the stirring system. Both the zeta potential and ΔG were lower in the aeration system than the stirring system. The zeta potential and ΔG results for the two systems suggest that aeration is more beneficial for sludge flocculation than stirring even though the sludge flocculation performance F/F0 in the stirring and aeration systems showed no obvious differences. Significant relationships between hydrodynamic parameters calculated based on the CFD model and average values of sludge properties in the stable phase showed that the Kolmogorov microscale, average flow velocity, and turbulence energy were appropriate hydrodynamic parameters for evaluating the flocculation performance F/F0, zeta potential, and ΔG, respectively.
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Affiliation(s)
- Qian Feng
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, No. 1 Xikang Road, Nanjing, 210098, China
| | - Ran Ge
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, No. 1 Xikang Road, Nanjing, 210098, China
| | - Yaqing Sun
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, No. 1 Xikang Road, Nanjing, 210098, China
| | - Fang Fang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, No. 1 Xikang Road, Nanjing, 210098, China
| | - Jingyang Luo
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, No. 1 Xikang Road, Nanjing, 210098, China
| | - Zhaoxia Xue
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, No. 1 Xikang Road, Nanjing, 210098, China
| | - Jiashun Cao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, No. 1 Xikang Road, Nanjing, 210098, China
| | - Ming Li
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, China.
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Feasibility and Carbon Footprint Analysis of Lime-Dried Sludge for Cement Production. SUSTAINABILITY 2020. [DOI: 10.3390/su12062500] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cement manufacturing and the treatment of sludge are considered both energy-intensive industries and major greenhouse gas (GHG) emitters. However, there are still few studies on comprehensive carbon footprint analysis for adding municipal sludge in the cement production. In this study, the lime-dried sludge blended with calcium oxide at the mass mixing ratio of 10% was utilized as raw material for the preparation of Portland cement. The chemical and physical properties of sludge were analyzed. A set of carbon footprint calculation methods of lime-drying treatment of sludge and reuse in cement kilns was then established to explore the feasibility of coprocessing lime-dried sludge in cement kilns. The results showed lime-dried sludge containing CaO, SiO2, Al2O3, and Fe2O3 was ideal for cement production as raw material. However, the water content of lime-dried sludge should be strictly limited. The lime-drying process presented the biggest carbon emission (962.1 kg CO2-eq/t sludge), accounting for 89.0% of total emissions. In the clinker-production phase, the lime-dried sludge as raw material substitute and energy source gained carbon credit of 578.8 and 214.2 kg CO2-eq/t sludge, respectively. The sludge used for producing cement clinker could reduce carbon emissions by 38.5% to 51.7%. The addition ratio of lime and stacking time in the sludge lime-drying process could greatly affect the carbon footprint of coprocessing lime-dried sludge in cement kiln.
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Improvements on activated sludge settling and flocculation using biomass-based fly ash as activator. Sci Rep 2019; 9:14590. [PMID: 31601839 PMCID: PMC6787012 DOI: 10.1038/s41598-019-50879-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/18/2019] [Indexed: 11/08/2022] Open
Abstract
Biomass-based fly ash and wastewater are undesired products of the pulping industry. Recently, the use of biomass-based fly ash as an adsorbent (i.e., a valued material) for constituents of wastewater effluents was reported. In this work, the settling performance and properties of activated sludge were studied in the presence of fly ash. Upon mixing, fly ash increased the zeta potential of the sludge from -31 mV to -28 mV, which was due to the release of cationic ions from fly ash in the sludge suspension. The sludge settling and its flocculation affinity were improved through the complexation of flocs and released cation ions from fly ash. The relationships between the protein/polysaccharide (PN/PS) ratio and the content of extracellular polymeric substances (EPS) as well as the ratio and the properties of the sludge flocs were determined. A correlation between the total loosely bound-EPS (LB-EPS) content and the effluent suspended solids (ESS) (Pearson's coefficient, rp = 0.83) was observed. The performance of sludge flocculation and settling were much more closely correlated with LB-EPS than with tightly bound EPS (TB-EPS). Scanning electron microscopy (SEM) analysis of sludge flocs before and after EPS extraction showed that the sludge flocs contained a large number of microorganisms, mainly Bacillus and Cocci. The amount of LB-EPS had an adverse influence on bioflocculation, effluent clarification and sludge settling affinity. The sludge properties had a moderate relationship with the PN/PS ratio of LB-EPS. Also, no correlation could be established between the ratio and the TB-EPS content.
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24
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The microbial community in filamentous bulking sludge with the ultra-low sludge loading and long sludge retention time in oxidation ditch. Sci Rep 2019; 9:13693. [PMID: 31548550 PMCID: PMC6757048 DOI: 10.1038/s41598-019-50086-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 08/31/2019] [Indexed: 12/20/2022] Open
Abstract
Sludge bulking is a major problem that restricts the development of the activated sludge process. The microbial community responsible for sludge bulking varies depending on water quality and operational conditions. This study analysed the microbial community of bulking sludge in oxidation ditch with ultra-low sludge loading and long sludge retention time using high-throughput sequencing. The study found that the relative abundance of bacterial genus Saprospiraceae_norank was the highest in bulking sludge, reaching 13.39-28.83%, followed by Comamonadaceae_unclassified, Ardenticatenia_norank and Tetrasphaera, with the relative abundance of 4.59-11.08%, 0.52-16.60% and 0.17-8.92% respectively. In contrast, the relative abundance of bacteria that easily caused sludge bulking including Microthrix (0.54-2.47%), Trichococcus (0.32-1.71%), Gordonia (0.14-1.28%), and Thiothrix (0.01-0.06%) were relatively low. Saprospiraceae_norank was predominant and induced sludge bulking in oxidation ditch. The relative abundance of fungal genus Trichosporon was the highest in bulking sludge, reaching 16.95-24.98%, while other fungal genera were Saccharomycetales_unclassified (5.59-14.55%), Ascomycota_norank (1.45-13.51%), Galactomyces (5.23-11.23%), and Debaryomyces (7.69-9.42%), whereas Trichosporon was the dominant fungal genus in bulking sludge. This study reported that excessive Saprospiraceae_norank can induce sludge bulking for the first time, which provides important knowledge to control sludge bulking.
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25
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Chen B, Yang Z, Pan J, Ren Y, Wu H, Wei C. Functional identification behind gravity-separated sludge in high concentration organic coking wastewater: Microbial aggregation, apoptosis-like decay and community. WATER RESEARCH 2019; 150:120-128. [PMID: 30508709 DOI: 10.1016/j.watres.2018.11.040] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 11/16/2018] [Accepted: 11/16/2018] [Indexed: 06/09/2023]
Abstract
Functional identification and elimination of activity-decayed sludge are helpful for improving the performance of biological treatment process. However, cell decay-associated changes in biological functions have not been explored for gravity-separated sludge. In this work, sludge flocs from the aerobic basin of a wastewater treatment plant treating high-concentration organic coking wastewater was fractionated according to settling velocity, i.e. sludge F (fast settling), sludge M (moderate settling) and sludge S (slow settling). Sludge volume index (SVI), mean floc size, dehydrogenase activity, specific oxygen uptake rate (SOUR), extracellular polymeric substances (EPS) content and aggregation interaction were investigated in the fractionated sludges. Apoptosis-like decayed cell distribution (ALDCD), a novel property of sludge, was proposed to describe sludge decay based on cell membrane variation. ALDCD of sludge F was 6.64% and 13.5% lower than sludge M and S, respectively. Microbial community and functional prediction revealed that sludge F exhibited the highest microbial potential for organic removal and sludge M had the highest potential for nitrogen metabolism while sludge S had the lowest potential for both. Our analysis suggests that the treatment efficiency might be enhanced by retaining compact sludge flocs while eliminating dispersive sludge flocs. This study also facilitates the identification and elimination of functional microbial groups from decayed sludge in wastewater treatment.
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Affiliation(s)
- Ben Chen
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Zhao Yang
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Jianxin Pan
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Yuan Ren
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou, 510006, PR China
| | - Haizhen Wu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, PR China
| | - Chaohai Wei
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou, 510006, PR China.
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26
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Efficient Culture of Rhodopseudomonas Palustris Using Landfill Leachate. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2018. [DOI: 10.22207/jpam.12.4.01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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27
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Vandekerckhove TGL, De Mulder C, Boon N, Vlaeminck SE. Temperature impact on sludge yield, settleability and kinetics of three heterotrophic conversions corroborates the prospect of thermophilic biological nitrogen removal. BIORESOURCE TECHNOLOGY 2018; 269:104-112. [PMID: 30153548 DOI: 10.1016/j.biortech.2018.08.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 06/08/2023]
Abstract
In specific municipal and industrial cases, thermophilic wastewater treatment (>45 °C) might bring cost advantages over commonly applied mesophilic processes (10-35 °C). To develop such a novel process, one needs sound parameters on kinetics, sludge yield and sludge settleability of three heterotrophic conversions: aerobic carbon removal, denitritation and denitrification. These features were evaluated in acetate-fed sequencing batch reactors (30, 40, 50 and 60 °C). Higher temperatures were accompanied by lower sludge production and maximum specific removal rates, resulting mainly from lower maximum growth rates. Thermophilic denitritation was demonstrated for the first time, with lower sludge production (18-26%), higher nitrogen removal rates (24-92%) and lower carbon requirement (40%) compared to denitrification. Acceptable settling of thermophilic aerobic (60 °C) and anoxic biomass (50 and 60 °C) was obtained. Overall, this parameter set may catalyze the establishment of thermophilic nitrogen removal, once nitritation and nitratation are characterized. Furthermore, waters with low COD/N ratio might benefit from thermophilic nitritation/denitritation.
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Affiliation(s)
- Tom G L Vandekerckhove
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | - Chaïm De Mulder
- BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | - Nico Boon
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | - Siegfried E Vlaeminck
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Gent, Belgium; Research Group of Sustainable Energy, Air and Water Technology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
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28
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Chen X, Si C, Fatehi P. Enhancement in biological treatment of pulping wastewater by fly ash. CHEMOSPHERE 2018; 210:1-9. [PMID: 29980067 DOI: 10.1016/j.chemosphere.2018.06.160] [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: 05/03/2018] [Revised: 06/20/2018] [Accepted: 06/26/2018] [Indexed: 05/26/2023]
Abstract
Sequential batch reactor (SBR) is a simple and flexible activated sludge process for industrial wastewater treatment. Also, biomass-based fly ash is a fairly plentiful and low-cost waste available in the pulp and paper industry. For treating wastewater of the pulping industry through a more efficient and economic approach, the integration of fly ash in the SBR process was investigated in this work. In this study, fly ash dosages of 0.2 wt% and 0.6 wt% were maintained in SBR1 and SBR2 systems, respectively, for treating the wastewater of the pulping industry. The findings indicated that adding fly ash to the bioreactors improved the settling and flocculation affinity of activated sludge without having any significant effect on the performance and the stability of the biological process. Lignin and color removals were 90.9% and 95% in SBR1 and 92.9% and 97.5% in SBR2, while the removals in the control reactor were 85.3% and 91.5%, respectively. The alkaline ions, such as Ca2+ and Mg2+, leached out from fly ash, which improved the sludge's properties, and this leaching reduced 22.1% and 40.5% of alkali consumptions in SBR1 and SBR2, respectively. The structure of sludge flocs in the reactors with and without fly ash was also studied. This technology is environmental friendly, cost-effective and suitable for a full-scale implementation in existing aerobic biological processes.
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Affiliation(s)
- Xiaoqian Chen
- Tianjin Key Laboratory of Pulp and Paper, Tianjin University of Science & Technology, Tianjin 300457, China; Chemical Engineering Department, Lakehead University, Thunder Bay, ON, Canada
| | - Chuanling Si
- Tianjin Key Laboratory of Pulp and Paper, Tianjin University of Science & Technology, Tianjin 300457, China.
| | - Pedram Fatehi
- Chemical Engineering Department, Lakehead University, Thunder Bay, ON, Canada.
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29
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Suresh A, Grygolowicz-Pawlak E, Pathak S, Poh LS, Abdul Majid MB, Dominiak D, Bugge TV, Gao X, Ng WJ. Understanding and optimization of the flocculation process in biological wastewater treatment processes: A review. CHEMOSPHERE 2018; 210:401-416. [PMID: 30015131 DOI: 10.1016/j.chemosphere.2018.07.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 06/21/2018] [Accepted: 07/05/2018] [Indexed: 05/19/2023]
Abstract
In the operation of biological wastewater treatment processes, fast sludge settling during liquid-solids disengagement is preferred as it affects effluent quality, treatment efficiency and plant operation economy. An important property of fast settling biological sludge is the ability to spontaneously form big and dense flocs (flocculation) that readily separates from water. Therefore, there had been much research to study the conditions that promote biological sludge flocculation. However, reported findings have often been inconsistent and this has possibly been due to the complex nature of the biological flocculation process. Thus, it has been challenging for wastewater treatment plant operators to extract practical information from the literature. The aim of this review is to summarize the current state of understanding of the factors that affect sludge flocculation so that evaluation of such information can be facilitated and strategize for intervention in the sludge flocculation and deflocculation process.
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Affiliation(s)
- Akshaykumar Suresh
- Nanyang Environment & Water Research Institute (NEWRI), Interdisciplinary Graduate School (IGS), Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798; Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Cleantech One #06-08, Singapore 637141
| | - Ewa Grygolowicz-Pawlak
- Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Cleantech One #06-08, Singapore 637141
| | - Santosh Pathak
- Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Cleantech One #06-08, Singapore 637141
| | - Leong Soon Poh
- Environmental Bio-innovations Group (EBiG), Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
| | - Maszenan Bin Abdul Majid
- Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Cleantech One #06-08, Singapore 637141
| | - Dominik Dominiak
- Grundfos Holding A/S, Poul Due Jensens Vej 7, DK-8850 Bjerringbro, Denmark
| | | | - Xin Gao
- Grundfos (Singapore) Pte Ltd, 25 Jalan Tukang, Singapore 619264
| | - Wun Jern Ng
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798; Environmental Bio-innovations Group (EBiG), Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.
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30
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Wang G, Wang Y, Liu L, Jin Y, Zhu N, Li X, Wang G, Chen G. Comprehensive assessment of microbial aggregation characteristics of activated sludge bioreactors using fuzzy clustering analysis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 162:296-303. [PMID: 30005402 DOI: 10.1016/j.ecoenv.2018.06.096] [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: 04/12/2018] [Revised: 06/14/2018] [Accepted: 06/30/2018] [Indexed: 06/08/2023]
Abstract
Understanding microbial aggregation dynamics in response to the often violent environmental fluctuations is important for activated sludge wastewater biotreatment practice, yet remains poorly understood. We investigated microbial aggregation process of an activated sludge reactor in response to various operating conditions of resource limitations, disinfectant and pH stresses, and quantified aggregation characteristics by employing a fuzzy clustering analysis (FCA) method. The results revealed that the FCA provided a means for comprehensive assessment of microbial aggregation dynamics of the bioreactor relying solely on simple parameter estimation. Proper disinfectant stress (of NaClO 1.00% or 2.00%) is a promising strategy to improve the comprehensive performance of microbial aggregation and sludge settleability. Nitrogen- (of C/N ratio > 40) and dissolved oxygen-limitations (of DO < 0.2 mg/L) had medium influence on the comprehensive performance of the activated sludge system, while little impacts for acidic and alkaline conditions. These quantitative estimations offer insights into the underlying bio-physicochemical processes of an activated sludge bioreactor in response to practical fluctuations that is often beyond typical assessment practice. In addition, it may represent a step towards uncoupling the complex biophysical interactions that is essential for optimized designing and proper engineering practice of biological wastewater treatment reactors.
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Affiliation(s)
- Gang Wang
- Department of Water & Soil Sciences, China Agricultural University, Beijing 100193, China
| | - Yan Wang
- Department of Water & Soil Sciences, China Agricultural University, Beijing 100193, China
| | - Li Liu
- Department of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yan Jin
- Department of Plant & Soil Sciences, University of Delaware, Newark, DE 19716, USA
| | - Ning Zhu
- Department of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Xing Li
- Department of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Guoqing Wang
- Nanjing Hydraulic Research Institute, Nanjing 210029, China
| | - Guowei Chen
- Department of Civil Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China.
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31
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Pang Q, Zhang R, Wen C, Han P. Fluid mud consolidation delayed by extracellular polymer substances. ENVIRONMENTAL TECHNOLOGY 2018; 39:2534-2541. [PMID: 28745138 DOI: 10.1080/09593330.2017.1360397] [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: 11/06/2016] [Accepted: 07/21/2017] [Indexed: 06/07/2023]
Abstract
A strain of bacterium identified as Burkholderia vietnamiensis was newly isolated and screened from mud deposited in a harbour basin. The effects of B. vietnamiensis on the fluid mud consolidation and the extracellular polymer substances (EPS) secreted by the microorganisms were examined in laboratory experiments. The experiments revealed the important characteristics of the EPS and their critical contents for nautical-depth applications. The self-weight consolidations in the settling and permeability regimes were best predicated by an exponential equation and a logarithmic equation, respectively. EPS cannot change the trend of sediment settling and consolidation, but its content is negatively correlated with the velocity of sediment consolidation. EPS with high polysaccharide/protein ratio is a potential reference to select bacteria for nautical-depth applications. The critical EPS content that would effectively extend the usage time of nautical depths was estimated as 2.34 g/l.
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Affiliation(s)
- Qixiu Pang
- a National Engineering Laboratory for Port Hydraulic Construction Technology, Key Laboratory of Engineering sediment of Ministry of Transport , Tianjin Research Institute of Water Transport Engineering , Tianjin , People's Republic of China
| | - Ruibo Zhang
- a National Engineering Laboratory for Port Hydraulic Construction Technology, Key Laboratory of Engineering sediment of Ministry of Transport , Tianjin Research Institute of Water Transport Engineering , Tianjin , People's Republic of China
| | - Chunpeng Wen
- a National Engineering Laboratory for Port Hydraulic Construction Technology, Key Laboratory of Engineering sediment of Ministry of Transport , Tianjin Research Institute of Water Transport Engineering , Tianjin , People's Republic of China
| | - Peipei Han
- b Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, College of Biotechnology , Tianjin University of Science and Technology , Tianjin , People's Republic of China
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32
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Qian H, Cheng Y, Yang C, Wu S, Zeng G, Xi J. Performance and biofilm characteristics of biotrickling filters for ethylbenzene removal in the presence of saponins. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:30021-30030. [PMID: 29177780 DOI: 10.1007/s11356-017-0776-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/15/2017] [Indexed: 06/07/2023]
Abstract
Saponins were applied to enhance ethylbenzene removal in biotrickling filters (BTFs), and comparison experiments were carried out to evaluate the effects of saponins on ethylbenzene removal and biofilm characteristics at various saponin concentrations. Results showed that the optimum concentration of saponins was 40 mg/L and a maximum removal efficiency (RE) of ethylbenzene reached 84.3%. When the inlet ethylbenzene concentration increased, ranging from 750 to 2300 mg/m3, the RE decreased from 92.1 to 60.8% and from 69.4 to 44.2% for BTF1 and BTF2 in which saponin was and was not added, respectively. The corresponding RE declined from 91.1 to 40.8% and from 71.5 to 35.8% with a decreased empty bed residence time ranging from 45 to 7.5 s. Additionally, significant differences existed between both BTFs not only in the contents of polysaccharide and proteins but also in the surface charge of biofilms, and the ratio of protein to polysaccharide increased with the increase of saponin concentration, which indicated the presumable effect of saponins on liquid-biofilm transfer rates of ethylbenzene. Mechanisms for the enhanced removal of hydrophobic volatile organic compounds at the presence of surfactants were also discussed.
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Affiliation(s)
- Hui Qian
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Yan Cheng
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Chunping Yang
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China.
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, Zhejiang, China.
| | - Shaohua Wu
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Guangming Zeng
- College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Jinying Xi
- School of Environment, Tsinghua University, Beijing, 100084, China.
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33
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Li X, Mei Q, Yan X, Dong B, Dai X, Yu L, Wang Y, Ding G, Yu F, Zhou J. Molecular characteristics of the refractory organic matter in the anaerobic and aerobic digestates of sewage sludge. RSC Adv 2018; 8:33138-33148. [PMID: 35548144 PMCID: PMC9086330 DOI: 10.1039/c8ra05009k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 09/12/2018] [Indexed: 11/21/2022] Open
Abstract
The chemical characteristics of the refractory organic matter in anaerobic and aerobic digestates are hardly known although they are significant for further improving the degradation of organic matter during sludge digestion. Thus, in this study, various techniques are used to analyze the molecular properties of the total organic matter in raw sludge and mesophilic anaerobic and aerobic digestates (AnD and AoD, respectively). The results show that AnD has lower organic matter content, but the maturity and aromatization of its organic matter are lower than those of AoD. The FTIR and XPS spectra show that AoD has higher proportions of protein-like and aromatic groups and lower percentages of polysaccharide-like materials and ammonia nitrogen compared with AnD. The solid-phase fluorescence spectra indicate that AoD has a higher content of fluorescence organic matter, but its biodegradability and chemical accessibility are lower than those of AnD. Pyrolysis GC/MS analysis shows that the digestates are enriched with more lignin-like and aromatic groups and contain lower oxycompounds compared with raw sludge, especially AoD. These findings provide new insights into the molecular characteristics of the refractory organic matter in anaerobic and aerobic digestates and also provide a possible strategy to further enhance the degradation of organic matter in sewage sludge. The chemical characteristics of the refractory organic matter in anaerobic and aerobic digestates are hardly known although they are significant for further improving the degradation of organic matter during sludge digestion.![]()
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Affiliation(s)
- Xiaowei Li
- School of Environmental and Chemical Engineering, Institute for the Conservation of Cultural Heritage, Shanghai University Shanghai 200444 People's Republic of China
| | - Qingqing Mei
- School of Environmental and Chemical Engineering, Institute for the Conservation of Cultural Heritage, Shanghai University Shanghai 200444 People's Republic of China
| | - Xiaofang Yan
- School of Environmental and Chemical Engineering, Institute for the Conservation of Cultural Heritage, Shanghai University Shanghai 200444 People's Republic of China
| | - Bin Dong
- State Key Laboratory of Pollution Control and Resources Reuse, National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University Shanghai 200092 People's Republic of China .,School of Civil Engineering and Architecture, Ningbo Institute of Technology, Zhejiang University Ningbo 315000 People's Republic of China
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resources Reuse, National Engineering Research Center for Urban Pollution Control, College of Environmental Science and Engineering, Tongji University Shanghai 200092 People's Republic of China .,Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092 People's Republic of China
| | - Liangliang Yu
- Yanjin Senior High School Shanghai 200122 P. R. China
| | - Yibo Wang
- Shanghai Key Lab of Bio-energy Crops, School of Life Sciences, Shanghai University Shanghai 200444 People's Republic of China
| | - Guoji Ding
- School of Environmental and Chemical Engineering, Institute for the Conservation of Cultural Heritage, Shanghai University Shanghai 200444 People's Republic of China
| | - Fang Yu
- School of Environmental and Chemical Engineering, Institute for the Conservation of Cultural Heritage, Shanghai University Shanghai 200444 People's Republic of China
| | - John Zhou
- School of Civil and Environmental Engineering, University of Technology Sydney 15 Broadway Sydney NSW 2007 Australia
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Zhang S, Sheng B, Lin W, Meng F. Day/night temperature differences (DNTD) trigger changes in nutrient removal and functional bacteria in membrane bioreactors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 636:1202-1210. [PMID: 29913582 DOI: 10.1016/j.scitotenv.2018.04.373] [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: 02/23/2018] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 06/08/2023]
Abstract
Temperature is a well-known environmental stress that influences both microbial metabolism and community structure in the biological wastewater treatment systems. In this study, responses of biological performance and sludge microbiota to the long-term day/night temperature differences (DNTD) were investigated in membrane bioreactors (MBRs). The results showed that the functional bacteria could sustained their ecological functions at low DNTD (20/30 °C), resulting in relatively stable performance with respect to nutrient removal. However, when the activated sludge was subjected to a high DNTD (17/33 °C), the effluent concentrations of COD, TN and TP were significantly higher in MBR-B than that in MBR-A. In addition, more severe membrane fouling occurred under the perturbation of high DNTD as revealed by the transmembrane pressure (TMP) profile, which was mainly attributed to the accumulation of extracellular polymeric substances (EPS). The results of 16S rRNA gene sequencing showed that DNTD showed negligible effect on the bacterial community structures. Nonetheless, the functional bacteria responded differently to DNTD, which were in accordance with the bioreactor performances. Specifically, Nitrospina (NOB) and Tetrasphaera (PAOs) appeared to be sensitive to both low and high DNTD. In contrast, a low DNTD showed marginal effects on the denitrifiers, while a high DNTD significantly decreased their abundances. More strikingly, filamentous bulking bacteria were found to be well-adapted to DNTD, indicating their tolerance to the daily temperature fluctuation. This study will advance our knowledge regarding the response of microbial ecology of activated sludge to daily temperature variations in full-scale MBRs.
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Affiliation(s)
- Shaoqing Zhang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, China
| | - Binbin Sheng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, China
| | - Wenting Lin
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, China
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, China.
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35
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Oliveira P, Alliet M, Coufort-Saudejaud C, Frances C. New insights in morphological analysis for managing activated sludge systems. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 77:2415-2425. [PMID: 29893730 DOI: 10.2166/wst.2018.189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In activated sludge (AS) process, the impact of the operational parameters on process efficiency is assumed to be correlated with the sludge properties. This study provides a better insight into these interactions by subjecting a laboratory-scale AS system to a sequence of operating condition modifications enabling typical situations of a wastewater treatment plant to be represented. Process performance was assessed and AS floc morphology (size, circularity, convexity, solidity and aspect ratio) was quantified by measuring 100,000 flocs per sample with an automated image analysis technique. Introducing 3D distributions, which combine morphological properties, allowed the identification of a filamentous bulking characterized by a floc population shift towards larger sizes and lower solidity and circularity values. Moreover, a washout phenomenon was characterized by smaller AS flocs and an increase in their solidity. Recycle ratio increase and COD:N ratio decrease both promoted a slight reduction of floc sizes and a constant evolution of circularity and convexity values. The analysis of the volume-based 3D distributions turned out to be a smart tool to combine size and shape data, allowing a deeper understanding of the dynamics of floc structure under process disturbances.
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Affiliation(s)
- Pedro Oliveira
- Université de Toulouse, Laboratoire de Génie Chimique, CNRS, 4, allée Émile Monso, Toulouse 31432, France
| | - Marion Alliet
- Université de Toulouse, Laboratoire de Génie Chimique, CNRS, 4, allée Émile Monso, Toulouse 31432, France
| | - Carole Coufort-Saudejaud
- Université de Toulouse, Laboratoire de Génie Chimique, CNRS, 4, allée Émile Monso, Toulouse 31432, France
| | - Christine Frances
- Université de Toulouse, Laboratoire de Génie Chimique, CNRS, 4, allée Émile Monso, Toulouse 31432, France
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36
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Biofouling control and sludge properties promotion through quorum quenching in membrane bioreactors at two aeration intensities. Biotechnol Lett 2018; 40:1067-1075. [DOI: 10.1007/s10529-018-2563-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 05/03/2018] [Indexed: 10/17/2022]
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37
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A low energy gravity-driven membrane bioreactor system for grey water treatment: Permeability and removal performance of organics. J Memb Sci 2017. [DOI: 10.1016/j.memsci.2017.08.037] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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38
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Chen X, Si C, Fatehi P. Impact of fly ash pretreatment on aerobic treatment of thermomechanical pulping spent liquor. Biotechnol Prog 2017; 34:370-378. [PMID: 29086486 DOI: 10.1002/btpr.2578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 08/24/2017] [Indexed: 11/08/2022]
Abstract
This study investigated the impact of biomass-based fly ash (FA) pretreatment on the biodegradability of a thermomechanical pulping spent liquor (TMPL) in an aerobic system. In this study, FA was mixed with TMPL under the conditions of 6 wt.% based on TMPL, 25°C and 10 h, which removed a part of recalcitrant organic materials and resulted in 68.0, 40.0, 60.1, 81.2 and 48.3% reductions in chemical oxygen demand (COD), biochemical oxygen demand (BOD), total organic carbon (TOC), lignin and sugar, respectively. FA-pretreated TMPL pressate (FA-TMPL) was biologically treated in an aerobic system of sequencing batch reactor (SBR). The performance of the biological treatment with and without FA pretreatment was studied in two parallel SBRs over three months. The combination of FA and biological treatments removed 97.3% of COD, 98.3% of BOD, 96.3% of lignin, 99.5% of sugar, and 98.1% of TOC. Without FA pretreatment, the biological system removed 87.3% of COD, 89% of BOD, 81.6% of lignin, 98.6% of sugars, and 90.5% of TOC. The results also confirmed that the settling ability of sludge, which was indicated as a sludge volume index, was reduced from 109.3 mL/g to 53.5 mL/g. In addition, the advantages of using FA pretreatment in aerobic systems were discussed in detail. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:370-378, 2018.
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Affiliation(s)
- Xiaoqian Chen
- Tianjin Key Laboratory of Pulp and Paper, Tianjin University of Science & Technology, Tianjin, 300457, China.,Chemical Engineering Department, Lakehead University, Thunder Bay, ON, Canada
| | - Chuanling Si
- Tianjin Key Laboratory of Pulp and Paper, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Pedram Fatehi
- Chemical Engineering Department, Lakehead University, Thunder Bay, ON, Canada
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39
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Ummalyma SB, Gnansounou E, Sukumaran RK, Sindhu R, Pandey A, Sahoo D. Bioflocculation: An alternative strategy for harvesting of microalgae - An overview. BIORESOURCE TECHNOLOGY 2017; 242:227-235. [PMID: 28314665 DOI: 10.1016/j.biortech.2017.02.097] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 02/20/2017] [Accepted: 02/22/2017] [Indexed: 05/05/2023]
Abstract
Microalgae based research has been extensively progressed for the production of value added products and biofuels. Potential application of microalgae for biofuel is recently gained more attention for possibilities of biodiesel and other high value metabolites. However, high cost of production of biomass associated with harvesting technologies is one of the major bottleneck for commercialization of algae based industrial product. Based on the operation economics, harvesting efficiency, technological possibilities, flocculation of algal biomass is a superior method for harvesting microalgae from the growth medium. In this article, latest trends of microalgal cell harvesting through flocculation are reviewed with emphasis on current progress and prospect in environmental friendly bio-based flocculation approach. Bio-flocculation based microalgae harvesting technologies is a promising strategy for low cost microalgal biomass production for various applications.
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Affiliation(s)
- Sabeela Beevi Ummalyma
- Institute of Bioresources and Sustainable Development (IBSD), Imphal 795001, Manipur, India.
| | - Edgard Gnansounou
- Ecole Polytechnique Federale de Lausanne, Institute of Urban and Regional Sciences, GC A3, Station 18, CH-1015 Lausanne, Switzerland
| | - Rajeev K Sukumaran
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695019, India
| | - Raveendran Sindhu
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695019, India
| | - Ashok Pandey
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695019, India; Center of Innovative and Applied Bioprocessing (CIAB), Mohali 160 071, India
| | - Dinabandhu Sahoo
- Institute of Bioresources and Sustainable Development (IBSD), Imphal 795001, Manipur, India
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40
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Manai I, Miladi B, El Mselmi A, Hamdi M, Bouallagui H. Improvement of activated sludge resistance to shock loading by fungal enzyme addition during textile wastewater treatment. ENVIRONMENTAL TECHNOLOGY 2017; 38:880-890. [PMID: 27456712 DOI: 10.1080/09593330.2016.1214623] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 07/15/2016] [Indexed: 06/06/2023]
Abstract
The effects of the additions of the fungal enzymatic extract were investigated in relation to the treatment of real textile wastewater (RTW) by the activated sludge process (ASP). The used enzyme cocktail was produced by a new isolated fungal Chaetomium globosum IMA1. The system that was operated with enzyme addition showed a better chemical oxygen demand (COD) removal efficiency (95%) compared to the control system (75%). In addition, the improvement of color removal (OD620) efficiencies was around 15%, when the newly consortium fungal enzymes was added. As the organic loading rate (OLR) increased from 0.33 g to 0.66 g COD L-1 d-1, a decrease in the performance of the two reactors was observed by monitoring the quality of treated effluents. However, the ASP working with enzyme addition showed a strong resistance to shock loadings and restored after few days compared to the control system, which was strongly inhibited. In fact, the enzyme addition improved the sludge volume index (SVI) and the activity of microorganisms. A high activity of laccase (300 U.L-1) enzyme was observed throughout the decolorization process in the improved system.
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Affiliation(s)
- Imène Manai
- a Lab Eco Tech Micro, INSAT , Université de Carthage , Tunis , Tunisia
| | - Baligh Miladi
- a Lab Eco Tech Micro, INSAT , Université de Carthage , Tunis , Tunisia
- b Laboratoire de Biologie Moléculaire, Ecole de Biologie Industrielle , Cergy , France
| | - Abdellatif El Mselmi
- b Laboratoire de Biologie Moléculaire, Ecole de Biologie Industrielle , Cergy , France
| | - Moktar Hamdi
- a Lab Eco Tech Micro, INSAT , Université de Carthage , Tunis , Tunisia
| | - Hassib Bouallagui
- a Lab Eco Tech Micro, INSAT , Université de Carthage , Tunis , Tunisia
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41
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Abstract
A thermophilic aerobic membrane reactor (TAMR) treating high-strength COD liquid wastes was submitted to an integrated investigation, with the aim of characterizing the biomass and its rheological behaviour. These processes are still scarcely adopted, also because the knowledge of their biology as well as of the physical-chemical properties of the sludge needs to be improved. In this paper, samples of mixed liquor were taken from a TAMR and submitted to fluorescent in situ hybridization for the identification and quantification of main bacterial groups. Measurements were also targeted at flocs features, filamentous bacteria, and microfauna, in order to characterize the sludge. The studied rheological properties were selected as they influence significantly the performances of membrane bioreactors (MBR) and, in particular, of the TAMR systems that operate under thermophilic conditions (i.e., around 50°C) with high MLSS concentrations (up to 200 gTS L−1). The proper description of the rheological behaviour of sludge represents a useful and fundamental aspect that allows characterizing the hydrodynamics of sludge suspension devoted to the optimization of the related processes. Therefore, in this study, the effects on the sludge rheology produced by the biomass concentration, pH, temperature, and aeration were analysed.
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42
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Ma SJ, Ding LL, Huang H, Geng JJ, Xu K, Zhang Y, Ren HQ. Effects of DO levels on surface force, cell membrane properties and microbial community dynamics of activated sludge. BIORESOURCE TECHNOLOGY 2016; 214:645-652. [PMID: 27187569 DOI: 10.1016/j.biortech.2016.04.132] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/26/2016] [Accepted: 04/28/2016] [Indexed: 06/05/2023]
Abstract
In this paper, we employ atomic force microscopy (AFM), fluorescence recovery after photobleaching (FRAP) technique, phospholipid fatty acids (PLFA) and MiSeq analysis to study the effects of traditional dissolved oxygen (DO) levels (0.71-1.32mg/L, 2.13-3.02mg/L and 4.31-5.16mg/L) on surface force, cell membrane properties and microbial community dynamics of activated sludge. Results showed that low DO level enhanced the surface force and roughness of activated sludge; the medium DO level decreased cell membrane fluidity by reducing the synthesis of branched fatty acids in the cell membrane; high DO level resulted in the highest protein content in the effluent by EEM scanning. Abundance of Micropruina, Zoogloea and Nakamurella increased and Paracoccus and Rudaea decreased with the increase of DO levels. RDA analysis suggested that saturated fatty acids (SFA), anteiso-fatty acids (AFA) and iso-fatty acids (IFA) were closely related to effluent quality as well as some genera.
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Affiliation(s)
- Si-Jia Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Li-Li Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hui Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Jin-Ju Geng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Ke Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Yan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hong-Qiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China.
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43
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Composition and aggregation of extracellular polymeric substances (EPS) in hyperhaline and municipal wastewater treatment plants. Sci Rep 2016; 6:26721. [PMID: 27220287 PMCID: PMC4879546 DOI: 10.1038/srep26721] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 05/05/2016] [Indexed: 11/08/2022] Open
Abstract
As important constituents of activated sludge flocs, extracellular polymeric substances (EPS) play significant roles in pollutants adsorption, the formation and maintenance of microbial aggregates, and the protection of microbes from external environmental stresses. In this work, EPS in activated sludge from a municipal wastewater treatment plant (M-WWTP) with anaerobic/anoxic/oxic (A(2)/O) process and a hyperhaline wastewater treatment plant (H-WWTP) with anaerobic/oxic (A/O) process were extracted by ultrasound method. The proteins and polysaccharides contents in EPS were determined by using a modified Lowry method and anthrone colorimetry respectively to analyze the detail differences in two types of WWTPs. Fourier transform-infrared spectroscopy and three-dimensional excitation-emission matrix fluorescence spectroscopy demonstrated proteins and polysaccharides were the dominant components of the two types of EPS, and the aromatic protein-like substances accounted for a larger proportion in EPS proteins. The results of the aggregation test indicated that EPS were good for the sludge aggregation, and the EPS in oxic sludge were more beneficial to sludge aggregation than that in anoxic sludge. Anoxic sludge EPS in H-WWTP showed a negligible effect on sludge aggregation. Comparative study on EPS of different tanks in the M-WWTP and H-WWTP was valuable for understanding the characteristics of EPS isolated from two typical wastewater treatment processes.
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44
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Xu RX, Li B, Zhang Y, Si L, Zhang XQ, Xie B. Response of biodegradation characteristics of unacclimated activated sludge to moderate pressure in a batch reactor. CHEMOSPHERE 2016; 148:41-46. [PMID: 26802261 DOI: 10.1016/j.chemosphere.2016.01.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 12/15/2015] [Accepted: 01/06/2016] [Indexed: 06/05/2023]
Abstract
This study was aimed to investigate the effect of moderate pressure on unacclimated activated sludge. Process of organic degradation, variation of carbon dioxide (CO2) concentration of off-gas and characteristics of extracellular polymeric substances (EPS) of activated sludge were analyzed using pressure-atmospheric comparative experiments in bench-scale batch reactors. It was found that moderate pressure increased the degradation rate more dramatically when the biological process ran under a higher organic load with much more oxygen demand, which illuminated that applications of the pressurized method to high concentration organic wastewaters would be more reasonable and practicable. High oxygen transfer impetus increased utilization of oxygen which not only promoted the biodegradation of organics in wastewater, but also led to more EPS consumption in activated sludge. CO2 concentration of off-gas was lower in the earlier stage due to CO2 being pressed into the liquid phase and converted into inorganic carbon (IC). More CO2 emission was observed during the pressurized aerobic process 160 min later. EPS in pressurized reactor was much lower, which may be an important way of sludge reduction by pressurized technology.
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Affiliation(s)
- Rui-Xiao Xu
- Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Bing Li
- Jiangsu Province Key Laboratory of Environmental Engineering, Nanjing 210000, China
| | - Yong Zhang
- Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Jiangsu Province Key Laboratory of Environmental Engineering, Nanjing 210000, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China.
| | - Ling Si
- Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Xian-Qiu Zhang
- Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Biao Xie
- Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023, China
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45
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Hao L, Liss SN, Liao BQ. Influence of COD:N ratio on sludge properties and their role in membrane fouling of a submerged membrane bioreactor. WATER RESEARCH 2016; 89:132-141. [PMID: 26657353 DOI: 10.1016/j.watres.2015.11.052] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/30/2015] [Accepted: 11/22/2015] [Indexed: 06/05/2023]
Abstract
The effect of COD:N ratio on sludge properties and their role in membrane fouling were examined using a well-controlled aerobic membrane bioreactor receiving a synthetic high strength wastewater containing glucose. Membrane performance was improved with an increase in the COD/N ratio (100:5-100:1.8) (i.e. reduced N dosage). Surface analysis of sludge by X-ray photoelectron spectroscopy (XPS) indicates significant differences in surface concentrations of elements C, O and N that were observed under different COD/N ratios, implying changes in the composition of extracellular polymeric substances (EPS). Fourier transform-infrared spectroscopy (FTIR) revealed a unique characteristic peak (CO bonds) at 1735 cm(-1) under nitrogen limitation conditions. Total EPS decreased with an increase in COD/N ratio, corresponding to a decrease in the proteins (PN) to carbohydrates (CH) ratio in EPS. There were no significant differences in the total soluble microbial products (SMPs) but the ratio of PN/CH in SMPs decreased with an increase in COD/N ratios. The results suggest that EPS and SMP composition and the presence of a small quantity of filamentous microorganisms played an important role in controlling membrane fouling.
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Affiliation(s)
- L Hao
- Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1, Canada
| | - S N Liss
- School of Environmental Studies and Department of Chemical Engineering, Queen's University, Kingston, ON K7L 3N6, Canada
| | - B Q Liao
- Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1, Canada.
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46
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Hong C, Wang Z, Xing Y, Li Y, Yang Q, Jia M, Feng L. Investigation of free radicals and carbon structures in chars generated from pyrolysis of antibiotic fermentation residue. RSC Adv 2016. [DOI: 10.1039/c6ra22192k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The aromatization level of AFR was enhanced sharply with the increase of pyrolysis temperature, and the free radicals in raw AFR samples gradually transformed into carbon free radicals on the aromatic structures in chars.
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Affiliation(s)
- Chen Hong
- School of Energy and Environmental Engineering
- University of Science and Technology Beijing
- Beijing 100083
- China
- Research Center for Eco-Environmental Sciences
| | - Zhiqiang Wang
- School of Energy and Environmental Engineering
- University of Science and Technology Beijing
- Beijing 100083
- China
| | - Yi Xing
- School of Energy and Environmental Engineering
- University of Science and Technology Beijing
- Beijing 100083
- China
- Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants
| | - Yifei Li
- School of Energy and Environmental Engineering
- University of Science and Technology Beijing
- Beijing 100083
- China
| | - Qiang Yang
- School of Energy and Environmental Engineering
- University of Science and Technology Beijing
- Beijing 100083
- China
| | - Mengmeng Jia
- School of Energy and Environmental Engineering
- University of Science and Technology Beijing
- Beijing 100083
- China
| | - Lihui Feng
- School of Energy and Environmental Engineering
- University of Science and Technology Beijing
- Beijing 100083
- China
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47
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Li X, Li Z, Dai X, Dong B, Tang Y. Micro-aerobic digestion of high-solid anaerobically digested sludge: further stabilization, microbial dynamics and phytotoxicity reduction. RSC Adv 2016. [DOI: 10.1039/c6ra11964f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Micro-aerobic digestion was firstly applied for further stabilization and phytotoxicity reduction of high-solid anaerobically digested sludge (ADS) in room temperature, mesophilic and thermophilic conditions.
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Affiliation(s)
- Xiaowei Li
- State Key Laboratory of Pollution Control and Resources Reuse
- National Engineering Research Center for Urban Pollution Control
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
| | - Zonghan Li
- State Key Laboratory of Pollution Control and Resources Reuse
- National Engineering Research Center for Urban Pollution Control
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resources Reuse
- National Engineering Research Center for Urban Pollution Control
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
| | - Bin Dong
- State Key Laboratory of Pollution Control and Resources Reuse
- National Engineering Research Center for Urban Pollution Control
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
| | - Yanfei Tang
- State Key Laboratory of Pollution Control and Resources Reuse
- National Engineering Research Center for Urban Pollution Control
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
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48
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Maceda-Veiga A, Webster G, Canals O, Salvadó H, Weightman AJ, Cable J. Chronic effects of temperature and nitrate pollution on Daphnia magna: Is this cladoceran suitable for widespread use as a tertiary treatment? WATER RESEARCH 2015; 83:141-152. [PMID: 26143271 DOI: 10.1016/j.watres.2015.06.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 05/11/2015] [Accepted: 06/21/2015] [Indexed: 06/04/2023]
Abstract
Effluent clarification and disinfection are major challenges in wastewater management. The cladoceran Daphnia magna has been proposed as a cost-effective and ecosystem-friendly option to clarify and disinfect secondary effluents, but its efficacy has not been fully tested under different sewage conditions. The present study explores the effects of temperature and nitrate on the efficacy of D. magna as a tertiary treatment at two different scales (individual assays and microcosms). Individual assays were employed to determine direct effects of temperature and/or nitrate on D. magna cultured in a suspension of organic matter. Using microcosms under the same environmental conditions, we explored the clearing efficacy of D. magna interacting with a natural microbial community. Individual assays revealed that D. magna mortality increased by 17% at 26 °C, 21% at >250 mg NO3(-)/l and by 60% at 26 °C and at >250 mg NO3(-)/l, and individuals displayed reduced body size, filtering rates and fecundity when compared to those at 21 °C and <40 mg NO3(-)/l. Improved performance under these conditions was also mirrored in the microcosms, with a higher density of D. magna (>100 ind/l) at 21 °C and <40 mg NO3(-)/l compared to the number (0-21 ind/l) at 26 °C and/or >250 mg NO3(-)/l. In the microcosms at 21 °C and <40 mg NO3(-)/l, turbidity and the density of bacteria, protists and micro-metazoa decreased in relation to those at 26 °C and/or >250 mg NO3(-)/l. Each treatment developed a unique and characteristic microbial assemblage, and D. magna was identified as the major driver of the community structure of protists and micro-metazoa. This enabled us to determine taxa vulnerability to D. magna grazing, and to re-define their tolerance thresholds for nitrate. In conclusion, this study increases our knowledge of how microbes respond to temperature and nitrate pollution, and highlights that D. magna efficacy as a tertiary treatment can be seriously compromised by variable environmental conditions.
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Affiliation(s)
| | - Gordon Webster
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Oriol Canals
- Laboratory of Protistology, Department of Animal Biology, Faculty of Biology, University of Barcelona, E-08028 Barcelona, Spain
| | - Humbert Salvadó
- Laboratory of Protistology, Department of Animal Biology, Faculty of Biology, University of Barcelona, E-08028 Barcelona, Spain
| | | | - Jo Cable
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
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49
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Wen Y, Zheng W, Yang Y, Cao A, Zhou Q. Influence of Al³⁺ addition on the flocculation and sedimentation of activated sludge: comparison of single and multiple dosing patterns. WATER RESEARCH 2015; 75:201-209. [PMID: 25770442 DOI: 10.1016/j.watres.2015.02.053] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 01/21/2015] [Accepted: 02/20/2015] [Indexed: 06/04/2023]
Abstract
In this study, the flocculation and sedimentation performance of activated sludge (AS) with single and multiple dosing of trivalent aluminum (Al(3+)) were studied. The AS samples were cultivated in sequencing batch reactors at 22 °C. The dosages of Al(3+) were 0.00, 0.125, 0.5, 1.0, and 1.5 meq/L for single dosing, and 0.1 meq/L for multiple dosing. Under single dosing conditions, as Al(3+) dosage increased, the zeta potential, total interaction energy, and effluent turbidity decreased, whereas the sludge volume index (SVI) increased, indicating that single Al(3+) dosing could enhance sludge flocculation, but deteriorate sedimentation. By comparison, adding an equal amount of Al(3+) through multiple dosing achieved a similar reduction in turbidity, but the zeta potential was higher, while the loosely bound extracellular polymeric substances (LB-EPS) content and SVI remarkably declined. Although the difference in the flocculation performances between the two dosing patterns was not significant, the underlying mechanisms were quite distinct: the interaction energy played a more important role under single dosing conditions, whereas multiple dosing was more effective in reducing the EPS content. Multiple dosing, which allows sufficient time for sludge restructuring and floc aggregation, could simultaneously optimize sludge flocculation and sedimentation.
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Affiliation(s)
- Yue Wen
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
| | - Wanlin Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Yundi Yang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor 48104, MI, USA
| | - Asheng Cao
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Municicpal Engineering Design Institute (Group) CO., LTD., Shanghai 200092, PR China
| | - Qi Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
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50
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Minardi ER, Chakraborty S, Calabrò V, Curcio S, Drioli E. Membrane applications for biogas production and purification processes: an overview on a smart alternative for process intensification. RSC Adv 2015. [DOI: 10.1039/c4ra11819g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Biogas is the result of a complex conversion process that takes place because of the metabolic activity of various types of bacteria.
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Affiliation(s)
- Eros Rosalbino Minardi
- Department of Informatics, Modeling, Electronics and Systems Engineering (D.I.M.E.S.)
- Laboratory of Transport Phenomena and Biotechnology
- University of Calabria
- Rende (CS)
- Italy
| | - Sudip Chakraborty
- Department of Informatics, Modeling, Electronics and Systems Engineering (D.I.M.E.S.)
- Laboratory of Transport Phenomena and Biotechnology
- University of Calabria
- Rende (CS)
- Italy
| | - Vincenza Calabrò
- Department of Informatics, Modeling, Electronics and Systems Engineering (D.I.M.E.S.)
- Laboratory of Transport Phenomena and Biotechnology
- University of Calabria
- Rende (CS)
- Italy
| | - Stefano Curcio
- Department of Informatics, Modeling, Electronics and Systems Engineering (D.I.M.E.S.)
- Laboratory of Transport Phenomena and Biotechnology
- University of Calabria
- Rende (CS)
- Italy
| | - Enrico Drioli
- Hanyang University
- WCU Energy Engineering Department
- Seoul
- South Korea
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