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Cen X, Duan H, Hu Z, Huang X, Li J, Yuan Z, Zheng M. Multifaceted benefits of magnesium hydroxide dosing in sewer systems: Impacts on downstream wastewater treatment processes. Water Res 2023; 247:120788. [PMID: 37924683 DOI: 10.1016/j.watres.2023.120788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 11/06/2023]
Abstract
Magnesium hydroxide [Mg(OH)2] is a non-hazardous chemical widely applied in sewer systems for managing odour and corrosion. Despite its proven effectiveness in mitigating these issues, the impacts of dosing Mg(OH)2 in sewers on downstream wastewater treatment plants have not been comprehensively investigated. Through a one-year operation of laboratory-scale urban wastewater systems, including sewer reactors, sequencing batch reactors, and anaerobic sludge digesters, the findings indicated that Mg(OH)2 dosing in sewer systems had multifaceted benefits on downstream treatment processes. Compared to the control, the Mg(OH)2-dosed experimental system displayed elevated sewage pH (8.8±0.1vs 7.1±0.1), reduced sulfide concentration by 35.1%±4.9% (6.7±0.9mgSL-1), and lower methane concentration by 58.0%±4.9% (19.1±3.6mgCODL-1). Additionally, it increased alkalinity by 16.3%±2.2% (51.9±5.4mgCaCO3L-1), and volatile fatty acids concentration by 207.4%±22.2% (56.6±9.0mgCODL-1) in sewer effluent. While these changes offered limited advantages for downstream nitrogen removal in systems with sufficient alkalinity and carbon sources, significant improvements in ammonium oxidation rate and NOx reduction rate were observed in cases with limited alkalinity and carbon sources availability. Moreover, Mg(OH)2 dosing in upstream did not have any detrimental effects on anaerobic sludge digesters. Magnesium-phosphate precipitation led to a 31.7%±4.1% reduction in phosphate concertation in anaerobic digester sludge supernatant (56.1±10.4mgPL-1). The retention of magnesium in sludge increased settleability by 13.9%±1.6% and improved digested sludge dewaterability by 10.7%±5.3%. Consequently, the use of Mg(OH)2 dosing in sewers could potentially reduce downstream chemical demand and costs for carbon sources (e.g., acetate), pH adjustment and sludge dewatering.
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Affiliation(s)
- Xiaotong Cen
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, Brisbane, Queensland, Australia
| | - Haoran Duan
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, Brisbane, Queensland, Australia
| | - Zhetai Hu
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, Brisbane, Queensland, Australia
| | - Xin Huang
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, Brisbane, Queensland, Australia
| | - Jiaying Li
- Queensland Alliance for Environmental Health Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Zhiguo Yuan
- School of Energy and Environment, City University of Hong Kong, Hong Kong SAR, China
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, Brisbane, Queensland, Australia.
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2
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Cen X, Li J, Jiang G, Zheng M. A critical review of chemical uses in urban sewer systems. Water Res 2023; 240:120108. [PMID: 37257296 DOI: 10.1016/j.watres.2023.120108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/13/2023] [Accepted: 05/20/2023] [Indexed: 06/02/2023]
Abstract
Chemical dosing is the most used strategy for sulfide and methane abatement in urban sewer systems. Although conventional physicochemical methods, such as sulfide oxidation (e.g., oxygen/nitrate), precipitation (e.g., iron salts), and pH elevation (e.g., magnesium hydroxide/sodium hydroxide) have been used since the last century, the high chemical cost, large environmental footprint, and side-effects on downstream treatment processes demand a sustainable and cost-effective alternative to these approaches. In this paper, we aimed to review the currently used chemicals and significant progress made in sustainable sulfide and methane abatement technology, including 1) the use of bio-inhibitors, 2) in situ chemical production, and 3) an effective dosing strategy. To enhance the cost-effectiveness of chemical applications in urban sewer systems, two research directions have emerged: 1) online control and optimization of chemical dosing strategies and 2) integrated use of chemicals in urban sewer and wastewater treatment systems. The integration of these approaches offers considerable system-wide benefits; however, further development and comprehensive studies are required.
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Affiliation(s)
- Xiaotong Cen
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Jiuling Li
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Guangming Jiang
- School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia.
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Zhang L, Qiu YY, Sharma KR, Shi T, Song Y, Sun J, Liang Z, Yuan Z, Jiang F. Hydrogen sulfide control in sewer systems: A critical review of recent progress. Water Res 2023; 240:120046. [PMID: 37224665 DOI: 10.1016/j.watres.2023.120046] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 04/17/2023] [Accepted: 05/02/2023] [Indexed: 05/26/2023]
Abstract
In sewer systems where anaerobic conditions are present, sulfate-reducing bacteria reduce sulfate to hydrogen sulfide (H2S), leading to sewer corrosion and odor emission. Various sulfide/corrosion control strategies have been proposed, demonstrated, and optimized in the past decades. These included (1) chemical addition to sewage to reduce sulfide formation, to remove dissolved sulfide after its formation, or to reduce H2S emission from sewage to sewer air, (2) ventilation to reduce the H2S and humidity levels in sewer air, and (3) amendments of pipe materials/surfaces to retard corrosion. This work aims to comprehensively review both the commonly used sulfide control measures and the emerging technologies, and to shed light on their underlying mechanisms. The optimal use of the above-stated strategies is also analyzed and discussed in depth. The key knowledge gaps and major challenges associated with these control strategies are identified and strategies dealing with these gaps and challenges are recommended. Finally, we emphasize a holistic approach to sulfide control by managing sewer networks as an integral part of an urban water system.
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Affiliation(s)
- Liang Zhang
- Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Yan-Ying Qiu
- Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Keshab R Sharma
- Australian Centre for Water and Environmental Biotechnology (ACWEB), The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Tao Shi
- Australian Centre for Water and Environmental Biotechnology (ACWEB), The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Yarong Song
- Australian Centre for Water and Environmental Biotechnology (ACWEB), The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jianliang Sun
- School of Environment, South China Normal University, Guangzhou, China
| | - Zhensheng Liang
- Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology (ACWEB), The University of Queensland, St. Lucia, QLD 4072, Australia; School of Energy and Environment, City University of Hong Kong, Hong Kong, China.
| | - Feng Jiang
- Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China.
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Jia Y, Zheng F, Maier HR, Ostfeld A, Creaco E, Savic D, Langeveld J, Kapelan Z. Water quality modeling in sewer networks: Review and future research directions. Water Res 2021; 202:117419. [PMID: 34274902 DOI: 10.1016/j.watres.2021.117419] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/20/2021] [Accepted: 07/04/2021] [Indexed: 06/13/2023]
Abstract
Urban sewer networks (SNs) are increasingly facing water quality issues as a result of many challenges, such as population growth, urbanization and climate change. A promising way to addressing these issues is by developing and using water quality models. Many of these models have been developed in recent years to facilitate the management of SNs. Given the proliferation of different water quality models and the promise they have shown, it is timely to assess the state-of-the-art in this field, to identify potential challenges and suggest future research directions. In this review, model types, modeled quality parameters, modeling purpose, data availability, type of case studies and model performance evaluation are critically analyzed and discussed based on a review of 110 papers published between 2010 and 2019. The review identified that applications of empirical and kinetic models dominate those of data-driven models for addressing water quality issues. The majority of models are developed for prediction and process understanding using experimental or field sampled data. While many models have been applied to real problems, the corresponding prediction accuracies are overall moderate or, in some cases, low, especially when dealing with larger SNs. The review also identified the most common issues associated with water quality modeling of SNs and based on these proposed several future research directions. These include the identification of appropriate data resolutions for the development of different SN models, the need and opportunity to develop hybrid SN models and the improvement of SN model transferability.
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Affiliation(s)
- Yueyi Jia
- College of Civil Engineering and Architecture, Zhejiang University, China.
| | - Feifei Zheng
- College of Civil Engineering and Architecture, Anzhong Building, Zijingang Campus, Zhejiang University, Zhejiang University, A501, , 866 Yuhangtang Rd, Hangzhou 310058, China.
| | - Holger R Maier
- School of Civil, Environmental and Mining Engineering, The University of Adelaide, Australia.
| | - Avi Ostfeld
- Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
| | - Enrico Creaco
- Dipartimento di Ingegneria Civile e Architettura, University of Pavia, Via Ferrata 3 Pavia 27100, Italy; School of Civil, Environmental and Mining Engineering, The University of Adelaide, Australia.
| | - Dragan Savic
- KWR Water Research Institute, the Netherlands; Centre for Water Systems, University of Exeter, United Kingdom; Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Malaysia.
| | - Jeroen Langeveld
- Faculty of Civil Engineering and Geosciences, Delft University of Technology, the Netherlands.
| | - Zoran Kapelan
- Faculty of Civil Engineering and Geosciences, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, the Netherlands; Centre for Water Systems, University of Exeter, North Park Road, Exeter EX4 4QF, United Kingdom.
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5
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Kulandaivelu J, Shrestha S, Khan W, Dwyer J, Steward A, Bell L, Mcphee P, Smith P, Hu S, Yuan Z, Jiang G. Full-scale investigation of ferrous dosing in sewers and a wastewater treatment plant for multiple benefits. Chemosphere 2020; 250:126221. [PMID: 32114337 DOI: 10.1016/j.chemosphere.2020.126221] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 01/17/2020] [Accepted: 02/13/2020] [Indexed: 05/06/2023]
Abstract
This study demonstrates the full scale application of iron dosing in a metropolitan wastewater treatment plant (WWTP) and the upstream sewer system for multiple benefits. Two different dosing locations, i.e., the WWTP inlet works (Trial-1) and upstream sewer network (Trial-2) were tested in this study. Both dosing trials achieved multiple benefits such as sulfide control, phosphate removal and improved sludge dewaterability. During Trial-1, a sulfide reduction of >90% was achieved at high dosing rates (>19 kgFe ML-1) of ferrous chloride in the inlet works and in Trial-2 the in-sewer ferrous dosing had significant gas phase hydrogen sulfide (H2S) concentration reduction in the sewer network. The ferrous dosing enhanced the phosphate removal in the bioreactor up to 76% and 53 ± 2% during Trial-1 & 2, respectively. The iron ending up in the anaerobic sludge digester reduced the biogas H2S concentration by up to 36% and 45%, respectively. The dewaterability of the digested sludge was improved, with relative increases of 9.7% and 9.8%, respectively. The presence of primary clarifier showed limited impact on the downstream availability of iron for achieving the afore-mentioned multiple benefits. The iron dosing enhanced the total chemical oxygen demand removal in the primary clarifier reaching up to 49% at the high dose rates during Trial-1 and 42 ± 1% during Trial-2. This study demonstrated that multiple benefits could be achieved independent of the iron dosing location (i.e., at the WWTP inlet or in the network). Further, iron dosing at both locations enhances primary settling, beneficial for bioenergy recovery from wastewater.
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Affiliation(s)
| | - Sohan Shrestha
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Wakib Khan
- Queensland Urban Utilities, Brisbane, QLD, Australia
| | - Jason Dwyer
- Queensland Urban Utilities, Brisbane, QLD, Australia
| | - Alan Steward
- Queensland Urban Utilities, Brisbane, QLD, Australia
| | - Leo Bell
- Queensland Urban Utilities, Brisbane, QLD, Australia
| | - Paul Mcphee
- Queensland Urban Utilities, Brisbane, QLD, Australia
| | - Peter Smith
- Queensland Urban Utilities, Brisbane, QLD, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Guangming Jiang
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia; School of Civil, Mining & Environmental Engineering, University of Wollongong, Wollongong, NSW, Australia.
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6
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Yuan Z, Olsson G, Cardell-Oliver R, van Schagen K, Marchi A, Deletic A, Urich C, Rauch W, Liu Y, Jiang G. Sweating the assets - The role of instrumentation, control and automation in urban water systems. Water Res 2019; 155:381-402. [PMID: 30861379 DOI: 10.1016/j.watres.2019.02.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 02/16/2019] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
Instrumentation, control and automation (ICA) are currently applied throughout the urban water system at water treatment plants, in water distribution networks, in sewer networks, and at wastewater treatment plants. However, researchers and practitioners specialising in respective urban water sub-systems do not frequently interact, and in most cases to date the application of ICA has been achieved in silo. Here, we review start-of-the-art ICA throughout these sub-systems, and discuss the benefits achieved in terms of performance improvement, cost reduction, and more importantly, the enhanced capacity of the existing infrastructure to cope with increased service demand caused by population growth and continued urbanisation. We emphasise the importance of integrated control within each of the sub-systems, and also across the entire urban water system. System-wide ICA will have increasing importance with the growing complexity of the urban water environment in cities of the future.
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Affiliation(s)
- Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, QLD, 4072, Australia; CRC for Water Sensitive Cities, PO Box 8000, VIC, 3800, Australia.
| | - Gustaf Olsson
- Industrial Automation, IEA, Lund University, Sweden; CRC for Water Sensitive Cities, PO Box 8000, VIC, 3800, Australia.
| | - Rachel Cardell-Oliver
- School of Computer Science & Software Engineering, The University of Western Australia, WA, 6009, Australia; CRC for Water Sensitive Cities, PO Box 8000, VIC, 3800, Australia
| | - Kim van Schagen
- Royal HaskoningDHV, PO Box 1132, 3800 BC, Amersfoort, the Netherlands
| | - Angela Marchi
- School of Civil, Environmental and Mining Engineering, University of Adelaide, SA, 5005, Australia; CRC for Water Sensitive Cities, PO Box 8000, VIC, 3800, Australia
| | - Ana Deletic
- Civil Engineering Department, Monash Water for Liveability, Monash University, VIC, 3800, Australia; CRC for Water Sensitive Cities, PO Box 8000, VIC, 3800, Australia
| | - Christian Urich
- Civil Engineering Department, Monash Water for Liveability, Monash University, VIC, 3800, Australia; CRC for Water Sensitive Cities, PO Box 8000, VIC, 3800, Australia
| | - Wolfgang Rauch
- Institute of Infrastructure Engineering, University Innsbruck, A-6020, Innsbruck, Austria; CRC for Water Sensitive Cities, PO Box 8000, VIC, 3800, Australia
| | - Yanchen Liu
- School of Environment, Tsinghua University, 100083, Beijing, China
| | - Guangming Jiang
- Advanced Water Management Centre, The University of Queensland, QLD, 4072, Australia; School of Civil, Mining and Environmental Engineering, University of Wollongong, NSW, 2522, Australia
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Rebosura M, Salehin S, Pikaar I, Sun X, Keller J, Sharma K, Yuan Z. A comprehensive laboratory assessment of the effects of sewer-dosed iron salts on wastewater treatment processes. Water Res 2018; 146:109-117. [PMID: 30241044 DOI: 10.1016/j.watres.2018.09.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/04/2018] [Accepted: 09/05/2018] [Indexed: 05/06/2023]
Abstract
The effect of iron-dosing in the sewer system, on wastewater treatment processes, was investigated using laboratory-scale wastewater systems comprising sewers, wastewater treatment reactors, sludge thickeners, and anaerobic sludge digesters. Two systems, fed with real domestic wastewater, were operated for over a year. The experimental system received ferric chloride (FeCl3) dosing at 10 mgFe L-1 in the sewer reactor whereas the control system received none. Wastewater, sludge and biogas were extensively sampled, and analysed for relevant parameters. The FeCl3-dosed experimental system displayed a decreased sulfide concentration (by 4.3 ± 0.5 mgS L-1) in sewer effluent, decreased phosphate concentration (by 4.7 ± 0.5 mgP L-1) in biological treatment reactor effluent, and decreased hydrogen sulfide concentration in biogas (911.5 ± 189.9 ppm to 130.0 ± 5.9 ppm), as compared with the control system. The biological nitrogen removal performance of the treatment reactor, and biogas production in the anaerobic digester were not affected by FeCl3-dosing. Furthermore, the dewaterability of the anaerobically digested sludge was enhanced by 17.7 ± 1.0%. These findings demonstrate that iron-dosing to sewers can achieve multiple benefits including sulfide removal in sewers, phosphorus removal during wastewater treatment, and hydrogen sulfide (H2S) removal during biogas generation. Therefore, an integrated approach should be taken when considering iron salts usage in an urban wastewater system.
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Affiliation(s)
- Mario Rebosura
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Sirajus Salehin
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia; The School of Civil Engineering, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Ilje Pikaar
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia; The School of Civil Engineering, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Xiaoyan Sun
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Jürg Keller
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Keshab Sharma
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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Abstract
Sewer system is an important source of methane formation and emission. Although some models were developed to predict methane production in sewers, the impact of microorganism amount was indicated indirectly. Here, seven laboratory scale sewers with varied wall-shear stresses were established. The biofilm thickness, microorganism amount, DO distribution, microorganism community in the biofilms and methane production in the sewers were measured. Based on experimental data, an empirical model was developed to directly describe the relationship between methane production, microorganism amount and wall-shear stress. The results showed that DO concentration decreased significantly along the biofilm depth under varied wall-shear stress, and the DO reduction rate was positively related to the intensity of wall-shear stress. The dominant archaea species in mature biofilms were similar whereas the proportions showed remarkable differences. The abundance of Methanospirillum in biofilms cultured at 2.0 Pa wall-shear stress was 53.08% more than that at 1.29 Pa. The maximum methane production rate, 2.04 mg/L wastewater day, was obtained when the wall-shear stress kept at 1.45 Pa, which was 1.2-fold higher than the minimum in sewer at 0.5 Pa. The R2 value of the established model was 0.95, the difference between the measurement and simulation was in the rage of 1.5–13.0%.
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Abstract
The intestinal microbiota is an ecosystem susceptible to external perturbations such as dietary changes and antibiotic therapies. Mathematical models of microbial communities could be of great value in the rational design of microbiota-tailoring diets and therapies. Here, we discuss how advances in another field, engineering of microbial communities for wastewater treatment bioreactors, could inspire development of mechanistic mathematical models of the gut microbiota. We review the state of the art in bioreactor modeling and current efforts in modeling the intestinal microbiota. Mathematical modeling could benefit greatly from the deluge of data emerging from metagenomic studies, but data-driven approaches such as network inference that aim to predict microbiome dynamics without explicit mechanistic knowledge seem better suited to model these data. Finally, we discuss how the integration of microbiome shotgun sequencing and metabolic modeling approaches such as flux balance analysis may fulfill the promise of a mechanistic model.
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Affiliation(s)
- Vanni Bucci
- Department of Biology, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02747, USA.
| | - Joao B Xavier
- Program in Computational Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 460, New York, NY 10065, USA.
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Sharma K, Derlon N, Hu S, Yuan Z. Modeling the pH effect on sulfidogenesis in anaerobic sewer biofilm. Water Res 2014; 49:175-185. [PMID: 24326022 DOI: 10.1016/j.watres.2013.11.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 11/08/2013] [Accepted: 11/14/2013] [Indexed: 06/03/2023]
Abstract
Wastewater pH affects the transfer of H2S from liquid to gas and hence impacts on the extent of odour and corrosion. Sewage pH may change significantly in sewer networks due to, for example, the fermentation of organic compounds, particularly when the hydraulic retention time is long, the discharge of trade wastes that are organic-rich or with extreme pH, and the intentional addition of alkali to raise the sewage pH. Such a variation of pH is expected to affect sulfate reduction by sewer biofilms. In this work, experimental studies were carried out to reveal the detailed effects of pH on sulfidogenesis by anaerobic sewer biofilms developed in a laboratory sewer reactor fed with real sewage, and the potential causes for the inhibitory effects observed under both high and low pH conditions. The data clearly showed that the sewer biofilm had the highest sulfate reduction rate at around neutral pH (6.5-7.5), and the activity decreased when pH was higher or lower. The data also suggested that the inhibiting effect at a higher pH is likely due to the inhibitory effects of free ammonia, while at a lower pH it is more likely due to the pH itself. An inhibition model formulated based on the above hypotheses was able to adequately describe the measured sulfide production rates under different pH levels and different free ammonia concentrations, as well as data previously reported in literature. The calibrated model was used to simulate sulfide production in a sewer network receiving alkali dosage. The model adequately predicted sulfide production in the network, which could not be achieved with a model not considering the pH effect.
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Affiliation(s)
- Keshab Sharma
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
| | - Nicolas Derlon
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
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11
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Sudarjanto G, Gutierrez O, Ren G, Yuan Z. Laboratory assessment of bioproducts for sulphide and methane control in sewer systems. Sci Total Environ 2013; 443:429-437. [PMID: 23220133 DOI: 10.1016/j.scitotenv.2012.10.083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 10/21/2012] [Accepted: 10/22/2012] [Indexed: 06/01/2023]
Abstract
The effectiveness of three bioproducts (also known as biomaterials) for liquid-phase biological treatment (LPBT) of sewer biofilms to control detrimental build-up of sulphide (H(2)S) and methane (CH(4)) in sewers was tested in a laboratory system mimicking a rising/force main sewer pipe. Bioproduct A claims to disrupt cell-to-cell communication of sewer anaerobic biofilms while Bioproducts B and C claim to enhance sulphidotrophic (sulphide-oxidising) capacity of the sewer biofilm, to avoid sulphide accumulation. The results demonstrated that all three bioproducts tested had no or negligible impact on sulphide or methane control, as opposed to traditional sulphide-controlling chemicals widely used by the wastewater industry such as oxygen, nitrate, iron salts and magnesium hydroxide. Those had previously been demonstrated to be effective using the same laboratory system with the same testing protocol. The implications of the findings are discussed. It is concluded that field application/trials of these three bioproducts are not warranted. It is recommended that other bioproducts should be subject to similar rigorous tests prior to being taken up by the water industry for field trials/application.
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Affiliation(s)
- Gatut Sudarjanto
- Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, Australia.
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