1
|
Krohn C, Jansriphibul K, Dias DA, Rees CA, Akker BVD, Boer JC, Plebanski M, Surapaneni A, O'Carroll D, Richard S, Batstone DJ, Ball AS. Dead in the water - Role of relic DNA and primer choice for targeted sequencing surveys of anaerobic sewage sludge intended for biological monitoring. Water Res 2024; 253:121354. [PMID: 38428359 DOI: 10.1016/j.watres.2024.121354] [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: 10/05/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/03/2024]
Abstract
DNA-based monitoring of microbial communities that are responsible for the performance of anaerobic digestion of sewage wastes has the potential to improve resource recoveries for wastewater treatment facilities. By treating sludge with propidium monoazide (PMA) prior to amplicon sequencing, this study explored how the presence of DNA from dead microbial biomass carried over with feed sludge may mislead process-relevant biomarkers, and whether primer choice impacts such assessments. Four common primers were selected for amplicon preparation, also to determine if universal primers have sufficient taxonomic or functional coverage for monitoring ecological performance; or whether two domain-specific primers for Bacteria and Archaea are necessary. Anaerobic sludges of three municipal continuously stirred-tank reactors in Victoria, Australia, were sampled at one time-point. A total of 240 amplicon libraries were sequenced on a Miseq using two universal and two domain-specific primer pairs. Untargeted metabolomics was chosen to complement biological interpretation of amplicon gene-based functional predictions. Diversity, taxonomy, phylogeny and functional potentials were systematically assessed using PICRUSt2, which can predict community wide pathway abundance. The two chosen universal primers provided similar diversity profiles of abundant Bacteria and Archaea, compared to the domain-specific primers. About 16 % of all detected prokaryotic genera covering 30 % of total abundances and 6 % of PICRUSt2-estimated pathway abundances were affected by PMA. This showed that dead biomass in the anaerobic digesters impacted DNA-based assessments, with implications for predicting active processes, such as methanogenesis, denitrification or the identification of organisms associated with biological foams. Hence, instead of running two sequencing runs with two different domain-specific primers, we propose conducting PMA-seq with universal primer pairs for routine performance monitoring. However, dead sludge biomass may have some predictive value. In principal component analysis the compositional variation of 239 sludge metabolites resembled that of 'dead-plus-alive' biomass, suggesting that dead organisms contributed to the potentially process-relevant sludge metabolome.
Collapse
Affiliation(s)
- Christian Krohn
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia.
| | - Kraiwut Jansriphibul
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia
| | - Daniel A Dias
- Centre for Advanced Sensory Science (CASS) Food Research Centre, School of Exercise and Nutrition Sciences, Deakin University, Melbourne Burwood Campus, 221 Burwood Highway, Burwood, Victoria 3125, Australia
| | - Catherine A Rees
- Melbourne Water Corporation, 990 La Trobe Street, Docklands, Victoria 3008, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, South Australia 5000, Australia
| | - Jennifer C Boer
- Cancer Aging and Vaccine Laboratory, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria 3083, Australia
| | - Magdalena Plebanski
- Cancer Aging and Vaccine Laboratory, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria 3083, Australia
| | - Aravind Surapaneni
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia; South East Water, 101 Wells Street, Frankston, Victoria 3199, Australia
| | - Denis O'Carroll
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Stuetz Richard
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Damien J Batstone
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia; Australian Centre for Water and Environmental Biotechnology (ACWEB), Gehrmann Building, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Andrew S Ball
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia
| |
Collapse
|
2
|
Krohn C, Khudur L, Dias DA, van den Akker B, Rees CA, Crosbie ND, Surapaneni A, O'Carroll DM, Stuetz RM, Batstone DJ, Ball AS. The role of microbial ecology in improving the performance of anaerobic digestion of sewage sludge. Front Microbiol 2022; 13:1079136. [PMID: 36590430 PMCID: PMC9801413 DOI: 10.3389/fmicb.2022.1079136] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
Abstract
The use of next-generation diagnostic tools to optimise the anaerobic digestion of municipal sewage sludge has the potential to increase renewable natural gas recovery, improve the reuse of biosolid fertilisers and help operators expand circular economies globally. This review aims to provide perspectives on the role of microbial ecology in improving digester performance in wastewater treatment plants, highlighting that a systems biology approach is fundamental for monitoring mesophilic anaerobic sewage sludge in continuously stirred reactor tanks. We further highlight the potential applications arising from investigations into sludge ecology. The principal limitation for improvements in methane recoveries or in process stability of anaerobic digestion, especially after pre-treatment or during co-digestion, are ecological knowledge gaps related to the front-end metabolism (hydrolysis and fermentation). Operational problems such as stable biological foaming are a key problem, for which ecological markers are a suitable approach. However, no biomarkers exist yet to assist in monitoring and management of clade-specific foaming potentials along with other risks, such as pollutants and pathogens. Fundamental ecological principles apply to anaerobic digestion, which presents opportunities to predict and manipulate reactor functions. The path ahead for mapping ecological markers on process endpoints and risk factors of anaerobic digestion will involve numerical ecology, an expanding field that employs metrics derived from alpha, beta, phylogenetic, taxonomic, and functional diversity, as well as from phenotypes or life strategies derived from genetic potentials. In contrast to addressing operational issues (as noted above), which are effectively addressed by whole population or individual biomarkers, broad improvement and optimisation of function will require enhancement of hydrolysis and acidogenic processes. This will require a discovery-based approach, which will involve integrative research involving the proteome and metabolome. This will utilise, but overcome current limitations of DNA-centric approaches, and likely have broad application outside the specific field of anaerobic digestion.
Collapse
Affiliation(s)
- Christian Krohn
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia,*Correspondence: Christian Krohn,
| | - Leadin Khudur
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia
| | - Daniel Anthony Dias
- School of Health and Biomedical Sciences, Discipline of Laboratory Medicine, STEM College, RMIT University, Bundoora, VIC, Australia
| | | | | | | | - Aravind Surapaneni
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia
| | - Denis M. O'Carroll
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Richard M. Stuetz
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Damien J. Batstone
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia,Australian Centre for Water and Environmental Biotechnology, Gehrmann Building, The University of Queensland, Brisbane, QLD, Australia
| | - Andrew S. Ball
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Bundoora, VIC, Australia
| |
Collapse
|
3
|
Li K, Duan H, Liu L, Qiu R, van den Akker B, Ni BJ, Chen T, Yin H, Yuan Z, Ye L. An Integrated First Principal and Deep Learning Approach for Modeling Nitrous Oxide Emissions from Wastewater Treatment Plants. Environ Sci Technol 2022; 56:2816-2826. [PMID: 35107268 DOI: 10.1021/acs.est.1c05020] [Citation(s) in RCA: 10] [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] [Indexed: 06/14/2023]
Abstract
Mathematical modeling plays a critical role toward the mitigation of nitrous oxide (N2O) emissions from wastewater treatment plants (WWTPs). In this work, we proposed a novel hybrid modeling approach by integrating the first principal model with deep learning techniques to predict N2O emissions. The hybrid model was successfully implemented and validated with the N2O emission data from a full-scale WWTP. This hybrid model is demonstrated to have higher accuracy for N2O emission modeling in the WWTP than the mechanistic model or pure deep learning model. Equally important, the hybrid model is more applicable than the pure deep learning model due to the lower requirement of data and the pure mechanistic model due to the less calibration requirement. This superior performance was due to the hybrid nature of the proposed model. It integrated the essential wastewater treatment knowledge as the first principal component and the less understood N2O production processes by the data-driven deep learning approach. The developed hybrid model was also successfully implemented under different circumstances for the prediction of N2O flux, which showed the generalizability of the model. The hybrid model also showed great potential to be applied for the N2O mitigation work. Nevertheless, the capability of the hybrid model in evaluating N2O mitigation strategies still requires validation with experiments. Going beyond N2O modeling in WWTP, the novel hybridization modeling concept can potentially be applied to other environmental systems.
Collapse
Affiliation(s)
- Kaili Li
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Haoran Duan
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Linfeng Liu
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ruihong Qiu
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, South Australia 5000, Australia
- School of Natural and Built Environments, University of South Australia, Adelaide, South Australia 5001, Australia
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5042, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Tong Chen
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Hongzhi Yin
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| |
Collapse
|
4
|
Thwaites BJ, Stuetz R, Short M, Reeve P, Alvarez-Gaitan JP, Dinesh N, Philips R, van den Akker B. Analysis of nitrous oxide emissions from aerobic granular sludge treating high saline municipal wastewater. Sci Total Environ 2021; 756:143653. [PMID: 33310220 DOI: 10.1016/j.scitotenv.2020.143653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 10/01/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 06/12/2023]
Abstract
Conventional activated sludge (CAS)-based wastewater treatment processes have the potential to emit high concentrations of nitrous oxide (N2O) during nitrification and denitrification, which can significantly impact the environmental performance and carbon footprint of wastewater treatment operations. While N2O emissions from CAS have been extensively studied, there is little knowledge of N2O emissions from aerobic granular sludge (AGS) which is now an increasingly popular secondary treatment alternative. The N2O emissions performance of AGS needs to be investigated to ensure that the positive benefits of AGS, such as increased capacity and stable nutrient removal, are not offset by higher emissions. This study quantified N2O emissions from a pilot-scale AGS reactor operated under a range of organic loading rates. A second CAS pilot plant was operated in parallel and under identical loading rates to allow for side-by-side comparison of N2O emissions from floc-based activated sludge. Under low loadings of <0.6 kg COD/m3/d the N2O emission factor from AGS and CAS were similar, at around 1.46 ± 0.1% g N2Oemitted/g ammonium loaded. A step increase in the organic loading rate increased N2O emissions from AGS more so than CAS which appeared to be attributed to the reactor feeding strategy that was required for AGS formation. The use of a separate anaerobic feeding phase which was followed by the aeration phase, resulted in extended periods of low dissolved oxygen (DO) concentrations combined with an initial high biomass ammonium loading rate, which favours N2O production and was exacerbated at higher organic loads. Conversely, the combined feeding plus aeration operation (aerobic feed) employed by the CAS system enabled a more even biomass ammonium loading rate and DO supply. This work has shown that while AGS has many operational benefits, the impacts that aeration profile, loading rate and feeding strategy have on N2O emissions must be considered.
Collapse
Affiliation(s)
- Benjamin J Thwaites
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Richard Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Michael Short
- Future Industries Institute, University of South Australia, Mawson Lakes 5095, South Australia, Australia
| | - Petra Reeve
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Juan-Pablo Alvarez-Gaitan
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Nirmala Dinesh
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Renae Philips
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia; Health and Environment Group, School of the Environment, Flinders University, Bedford Park, 5042, South Australia, Australia; School of Natural and Built Environments, University of South Australia, Mawson Lakes 5095, South Australia, Australia
| |
Collapse
|
5
|
Duan H, van den Akker B, Thwaites BJ, Peng L, Herman C, Pan Y, Ni BJ, Watt S, Yuan Z, Ye L. Mitigating nitrous oxide emissions at a full-scale wastewater treatment plant. Water Res 2020; 185:116196. [PMID: 32738601 DOI: 10.1016/j.watres.2020.116196] [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: 02/18/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 06/11/2023]
Abstract
Mitigation of nitrous oxide (N2O) emissions is of primary importance to meet the targets of reducing carbon footprints of wastewater treatment plants (WWTPs). Despite of a large amount of N2O mitigation studies conducted in laboratories, full-scale implementation of N2O mitigation is scarce, mainly due to uncertainties of mitigation effectiveness, validation of N2O mathematical model, risks to nutrient removal performance and additional costs. This study aims to address the uncertainties by investigating the quantification, development and implementation of N2O mitigation strategies at a full-scale sequencing batch reactor (SBR). To achieve this, N2O emission dynamics, nutrient removal performance and operation of the SBR were monitored to quantify N2O emissions, and identify the N2O generation mechanisms. N2O mitigation strategies centered on reducing dissolved oxygen (DO) levels were consequently proposed and evaluated using a multi-pathway N2O production mathematical model before implementation. The implemented mitigation strategy resulted in a 35% reduction in N2O emissions (from the emission factor of 0.89 ± 0.05 to 0.58 ± 0.06%), which was equivalent to annual reduction of 2.35 tonne of N2O from the studied WWTP. This could be mainly attributed to reductions in N2O generated via the NH2OH oxidation pathway due to the lowering of DO level. As the first reported mitigation strategy permanently implemented at a full scale WWTP, it showcased that the mitigation of N2O emissions at full-scale is feasible and that widely accepted N2O mitigation strategies developed in laboratory studies are also likely effective in full-scale plants. Furthermore, the close agreement between the validated and predicted N2O emission factors (0.58% vs 0.55%, respectively), showed that the N2O mathematical model is a useful tool to evaluate N2O mitigation strategies at full-scale. Importantly this work demonstrated that N2O mitigation does not necessarily require additional operational cost to meet reduction targets. In contrast, the N2O mitigation applied here reduced energy requirements for aeration by 20%. Equally important, long-term monitoring identified that N2O mitigation did not affect the nutrient removal performance of the plant. Finally, with the knowledge acquired in this study, a standard approach for mitigating N2O emissions from full-scale treatment plants was proposed.
Collapse
Affiliation(s)
- Haoran Duan
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia; School of Chemical Engineering, The University of Queensland, Brisbane, QLD, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, SA, Australia; School of Natural and Built Environments, University of South Australia, SA, Australia; College of Science and Engineering, Flinders University, SA, Australia
| | | | - Lai Peng
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Wuhan, Hubei, China
| | - Caroline Herman
- Adelaide Services Alliance (Allwater) - SUEZ Water, Adelaide, SA, Australia
| | - Yuting Pan
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Bing-Jie Ni
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Shane Watt
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD, Australia.
| |
Collapse
|
6
|
Yadav MK, Short MD, Gerber C, van den Akker B, Aryal R, Saint CP. Occurrence, removal and environmental risk of markers of five drugs of abuse in urban wastewater systems in South Australia. Environ Sci Pollut Res Int 2019; 26:33816-33826. [PMID: 29948683 DOI: 10.1007/s11356-018-2464-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 03/15/2018] [Accepted: 05/31/2018] [Indexed: 06/08/2023]
Abstract
The occurrence and fate of five drugs of abuse in raw influent and treated effluent wastewater were investigated over a period of 1 year in the Adelaide region of South Australia. Four wastewater treatment plants were chosen for this study and monitored for five drugs which included cocaine in the form of its metabolite benzoylecgonine (BE), methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA) and two opioids (codeine and morphine) during the period April 2016 to February 2017. Alongside concentrations in raw sewage, the levels of drugs in the treated effluent were assessed and removal efficiencies were calculated. Drug concentrations were measured by mixed-mode solid phase extraction and liquid chromatography coupled to a quadrupole mass spectrometer. Drug concentrations detected in the raw wastewater ranged from 7 to 6510 ng/L and < LOD to 4264 ng/L in treated effluent samples. Drug removal rates varied seasonally and spatially. The mass loads of drugs discharged into the environment were in descending order: codeine > methamphetamine > morphine > MDMA > BE. Results showed that all the targeted drugs were on average incompletely removed by wastewater treatment, with removal performance highest for morphine (94%) and lowest for MDMA (58%). A screening-level environmental risk assessment was subsequently performed for the drugs based on effluent wastewater concentrations. Based on calculated risk quotients, overall environmental risk for these compounds appears low, with codeine and methamphetamine likely to pose the greatest potential risk to receiving environments. Given the recognised limitations of current ecotoxicological models and risk assessment methods for these and other pharmaceutical drugs, the potential for environmental impacts associated with the continuous discharge of these compounds in wastewater effluents should not be overlooked.
Collapse
Affiliation(s)
- Meena K Yadav
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Michael D Short
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA, 5095, Australia
- Future Industries Institute, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Cobus Gerber
- School of Pharmacy and Medical Science, City East Campus, North Terrace, Playford Building, Level 4, Room 47, Adelaide, SA, 5000, Australia
| | - Ben van den Akker
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA, 5095, Australia
- Australian Water Quality Centre, SA Water, 250 Victoria Square, Adelaide SA 5000; GPO Box 1751, Adelaide, SA, 5001, Australia
| | - Rupak Aryal
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Christopher P Saint
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA, 5095, Australia.
- Future Industries Institute, University of South Australia, Mawson Lakes, SA, 5095, Australia.
- Division of Information Technology, Engineering and the Environment, University of South Australia, Mawson Lakes, SA, 5095, Australia.
| |
Collapse
|
7
|
Yadav MK, Short MD, Gerber C, Awad J, van den Akker B, Saint CP. Removal of emerging drugs of addiction by wastewater treatment and water recycling processes and impacts on effluent-associated environmental risk. Sci Total Environ 2019; 680:13-22. [PMID: 31100664 DOI: 10.1016/j.scitotenv.2019.05.068] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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: 03/11/2019] [Revised: 05/02/2019] [Accepted: 05/06/2019] [Indexed: 06/09/2023]
Abstract
Drugs of addiction, have been recognized as potential contaminants of concern to the environment. Effluent wastewater discharge is a major source of contamination to aquatic receiving environments. A year-long monitoring program was undertaken in Australia to characterise the fate of four emerging drugs of addiction: methamphetamine; MDMA; pharmaceutical opioids: codeine and morphine and a metabolite: benzoylecgonine in four wastewater treatment plants operating with different secondary treatment technologies: conventional activated sludge (CAS), membrane bioreactors (MBR), integrated fixed-film AS (IFAS) and sequencing batch reactor (SBR). The effect of subsequent tertiary treatment (coagulation/flocculation) on the removal efficiency was also assessed. Drugs were detected in influent and effluent samples (mean concentration ranged from 43-4777 and 17-1721 ng/L, respectively). Treated effluents had noticeably lower levels compared to raw influents. Removal efficiency of compounds depended on the secondary treatment employed, with IFAS and MBR performing the best with significant removal of compounds (≈90%) followed by CAS (54-96%) and lastly SBR (42-83%). Despite the low levels of drugs measured after the secondary treatment, near complete removal after tertiary treatment (≈99%) was recorded, which demonstrated the effectiveness of using the coagulation/flocculation process as an effective step for enhancing the removal efficiency. The levels of drugs were at a low level in the effluents released into the environment and used for recycling and all posed a low environmental risk in urban water courses based on the risk assessment. The information given here provides new and useful information to the water industry and regulators on the efficiency of drug removal in a range of wastewater treatment configurations.
Collapse
Affiliation(s)
- Meena K Yadav
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia
| | - Michael D Short
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia; Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia
| | - Cobus Gerber
- School of Pharmacy and Medical Science, City East Campus, Adelaide, SA 5000, Australia
| | - John Awad
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia
| | - Ben van den Akker
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia; SA Water Corporation, 250 Victoria Square, Adelaide, SA 5000, Australia
| | - Christopher P Saint
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia; Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia; Division of Information Technology, Engineering and the Environment, University of South Australia, Mawson Lakes, SA 5095, Australia.
| |
Collapse
|
8
|
Mai L, Lian Y, van den Akker B, Fallowfield HJ. Nitrification performance of high rate nitrifying trickling filters at low ammonia concentrations: does the aspect ratio matter? Environ Sci Pollut Res Int 2019; 26:20520-20529. [PMID: 31102227 DOI: 10.1007/s11356-019-05256-1] [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: 08/31/2018] [Accepted: 04/22/2019] [Indexed: 06/09/2023]
Abstract
Nitrifying trickling filters (NTFs) are often introduced to pre-treat waters before chlorination process, to reduce the ammonia-driven chlorine consumption in wastewater treatment. As a passive aerated system, the only power needed is to transport the water to the top of the filter for distribution. Thus, understanding the role of filter aspect ratio on ammonia oxidation might save energy cost. In the present study, a pilot-scale comparison NTF system was conducted on two filters with different aspect ratios (height/diameter) and the same specific surface area. The nitrification efficiencies of these two filters under relatively low influent ammonia-nitrogen concentrations (1.0-4.0 mg NH4-N L-1) were investigated. Results obtained from the present study indicated that the constructional aspect ratio of NTF showed no significant effect on nitrification performance of NTFs. Additionally, the operational parameters showed similar effects on nitrification in NTFs with different aspect ratios. Our findings could provide important information for the construction design of future NTFs.
Collapse
Affiliation(s)
- Lei Mai
- Department of Environmental Health, School of Environment, Flinders University, Bedford Park, SA, 5042, Australia.
- School of Environmental, Jinan University, Guangzhou, 511486, China.
| | - Yu Lian
- Department of Environmental Health, School of Environment, Flinders University, Bedford Park, SA, 5042, Australia
- School of Environmental Science and Technology, Hunan University, Yuelu District, Changsha, 410082, China
| | - Ben van den Akker
- Department of Environmental Health, School of Environment, Flinders University, Bedford Park, SA, 5042, Australia
- Australian Water Quality Centre, Adelaide, SA, 5001, Australia
| | - Howard J Fallowfield
- Department of Environmental Health, School of Environment, Flinders University, Bedford Park, SA, 5042, Australia.
| |
Collapse
|
9
|
Thwaites BJ, Short MD, Stuetz RM, Reeve PJ, Alvarez Gaitan JP, Dinesh N, van den Akker B. Comparing the performance of aerobic granular sludge versus conventional activated sludge for microbial log removal and effluent quality: Implications for water reuse. Water Res 2018; 145:442-452. [PMID: 30189399 DOI: 10.1016/j.watres.2018.08.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 05/10/2018] [Revised: 08/14/2018] [Accepted: 08/18/2018] [Indexed: 06/08/2023]
Abstract
The application of aerobic granular sludge (AGS) technology has increased in popularity, largely due to the smaller physical footprint, enhanced biological nutrient removal performance and ability to perform with a more stable operation when compared to conventional activated sludge (CAS) systems. To date, the ability of AGS to remove microbial pathogens such as; Escherichia coli, Giardia, and Cryptosporidium has not been reported. This study compared the log10 removal performance of commonly used pathogen surrogates (sulfite-reducing clostridia spores, f-RNA bacteriophage, E. coli and total coliforms) by AGS and CAS during the start-up phase, through to maturation. Results showed that AGS performed as well as CAS for the log10 removal performance of all microbial surrogates, except for spores which were removed more effectively by AGS most likely due to greater adherence of spores to the AGS biomass compared to CAS mixed liquor. Results suggest that AGS is capable of meeting or exceeding CAS-equivalent health-based targets for pathogen removal in the context of water recycling as well as not adversely affecting the secondary effluent water quality (suspended solids, turbidity and particle size) in terms of ultraviolet light transmissivity (254 nm). These findings confirmed for the first time that the adoption of AGS operation would not adversely impact downstream tertiary disinfection processes from altered water quality, nor would it require further pathogen treatment interventions in addition to what is already required for CAS systems.
Collapse
Affiliation(s)
- Benjamin J Thwaites
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Michael D Short
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia; Future Industries Institute, University of South Australia, Mawson Lakes, 5095, South Australia, Australia
| | - Richard M Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Petra J Reeve
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Juan-Pablo Alvarez Gaitan
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Nirmala Dinesh
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia; Health and Environment Group, School of the Environment, Flinders University, Bedford Park, 5042, South Australia, Australia; School of Natural and Built Environments, University of South Australia, Mawson Lakes, 5095, South Australia, Australia
| |
Collapse
|
10
|
Thwaites BJ, van den Akker B, Reeve PJ, Short MD, Dinesh N, Alvarez-Gaitan JP, Stuetz R. Ecology and performance of aerobic granular sludge treating high-saline municipal wastewater. Water Sci Technol 2018; 77:1107-1114. [PMID: 29488974 DOI: 10.2166/wst.2017.626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The successful development of aerobic granular sludge (AGS) for secondary wastewater treatment has been linked to a dedicated anaerobic feeding phase, which enables key microbes such as poly-phosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms to gain a competitive advantage over floc-forming organisms. The application of AGS to treat high-saline sewage and its subsequent impacts on microbial ecology, however, are less well understood. In this study, the impacts of high-saline sewage on AGS development, performance and ecology were investigated using molecular microbiology methods. Two feeding strategies were compared at pilot scale: a full (100%) anaerobic feed; and a partial (33%) anaerobic feed. The results were compared to a neighbouring full-scale conventional activated sludge (CAS) system (100% aerobic). We observed that AGS developed under decreased anaerobic contact showed a comparable formation, stability and nitrogen removal performance to the 100% anaerobically fed system. Analysis of the microbial ecology showed that the altered anaerobic contact had minimal effect on the abundances of the functional nitrifying and denitrifying bacteria and Archaea; however, there were notable ecological differences when comparing different sized granules. In contrast to previous work, a large enrichment in PAOs in AGS was not observed in high-saline wastewater, which coincided with poor observed phosphate removal performance. Instead, AGS exhibited a substantial enrichment in sulfide-oxidising bacteria, which was complemented by elemental analysis that identified the presence of elemental sulfur precipitation. The potential role for these organisms in AGS treating high-saline wastewater is discussed.
Collapse
Affiliation(s)
- Benjamin J Thwaites
- School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052, Australia E-mail:
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, South Australia 5000, Australia; School of Natural and Built Environments, University of South Australia, Mawson Lakes, South Australia 5095, Australia; Health and Environment Group, School of the Environment, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Petra J Reeve
- South Australian Water Corporation, Adelaide, South Australia 5000, Australia
| | - Michael D Short
- School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052, Australia E-mail: ; School of Natural and Built Environments, University of South Australia, Mawson Lakes, South Australia 5095, Australia; Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Nirmala Dinesh
- South Australian Water Corporation, Adelaide, South Australia 5000, Australia
| | | | - Richard Stuetz
- School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052, Australia E-mail:
| |
Collapse
|
11
|
Reeve PJ, Regel R, Le Moigne I, van den Akker B, Monis P, Dreyfus J, Beard H, Brehant A. Evaluating membrane performance in recycled water treatment plants for assets replacement strategy. Water Sci Technol 2017; 76:2941-2948. [PMID: 29210681 DOI: 10.2166/wst.2017.466] [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] [Indexed: 06/07/2023]
Abstract
Membranes are an important barrier used in recycled water treatment plants for pathogen removal. Understanding performance over operational life is important to inform membrane replacement. In this study, full scale virus challenge testing was conducted on newly commissioned membranes to validate virus log removal values for accreditation. After six years of operation, the membrane integrity was repeated to ensure compliance with the state regulatory health authority and gain an understanding of the asset's condition. Membrane performance was assessed using a combination of complementary tests including membrane autopsy and chemical tolerance testing to assess individual modules and selected membrane fibres, followed by a full scale virus challenge for whole of unit assessment. The results demonstrated that the aged membrane fibres were intact and had not been affected by long-term exposure to chlorine, which provides valuable information for membrane asset replacement strategies.
Collapse
Affiliation(s)
- Petra J Reeve
- South Australian Water Corporation, 250 Victoria Square, Adelaide SA 5000, Australia E-mail:
| | - Rudi Regel
- South Australian Water Corporation, 250 Victoria Square, Adelaide SA 5000, Australia E-mail:
| | | | - Ben van den Akker
- South Australian Water Corporation, 250 Victoria Square, Adelaide SA 5000, Australia E-mail:
| | - Paul Monis
- South Australian Water Corporation, 250 Victoria Square, Adelaide SA 5000, Australia E-mail:
| | - Jennifer Dreyfus
- Allwater, Adelaide Services Alliance, Adelaide SA 5000, Australia
| | - Helen Beard
- Allwater, Adelaide Services Alliance, Adelaide SA 5000, Australia
| | - Anne Brehant
- Suez, CIRSEE, 38 rue du président Wilson, 78230 Le Pecq, France
| |
Collapse
|
12
|
Yadav MK, Short MD, Aryal R, Gerber C, van den Akker B, Saint CP. Occurrence of illicit drugs in water and wastewater and their removal during wastewater treatment. Water Res 2017; 124:713-727. [PMID: 28843086 DOI: 10.1016/j.watres.2017.07.068] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [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: 04/15/2017] [Revised: 07/25/2017] [Accepted: 07/25/2017] [Indexed: 06/07/2023]
Abstract
This review critically evaluates the types and concentrations of key illicit drugs (cocaine, amphetamines, cannabinoids, opioids and their metabolites) found in wastewater, surface water and drinking water sources worldwide and what is known on the effectiveness of wastewater treatment in removing such compounds. It is also important to amass information on the trends in specific drug use as well as the sources of such compounds that enter the environment and we review current international knowledge on this. There are regional differences in the types and quantities of illicit drug consumption and this is reflected in the quantities detected in water. Generally, the levels of illicit drugs in wastewater effluents are lower than in raw influent, indicating that the majority of compounds can be at least partially removed by conventional treatment processes such as activated sludge or trickling filters. However, the literature also indicates that it is too simplistic to assume non-detection equates to drug removal and/or mitigation of associated risks, as there is evidence that some compounds may avoid detection via inadequate sampling and/or analysis protocols, or through conversion to transformation products. Partitioning of drugs from the water to the solids fraction (sludge/biosolids) may also simply shift the potential risk burden to a different environmental compartment and the review found no information on drug stability and persistence in biosolids. Generally speaking, activated sludge-type processes appear to offer better removal efficacy across a range of substances, but the lack of detail in many studies makes it difficult to comment on the most effective process configurations and operations. There is also a paucity of information on the removal effectiveness of alternative treatment processes. Research is also required on natural removal processes in both water and sediments that may over time facilitate further removal of these compounds in receiving environments.
Collapse
Affiliation(s)
- Meena K Yadav
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia.
| | - Michael D Short
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia; Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
| | - Rupak Aryal
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia.
| | - Cobus Gerber
- School of Pharmacy and Medical Science, City East Campus, North Terrace, Playford Building, Level 4, Room 47, Adelaide, SA 5000, Australia.
| | - Ben van den Akker
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia; Australian Water Quality Centre, SA Water, 250 Victoria Square, Adelaide SA 5000; GPO Box 1751, Adelaide SA 5001, Australia.
| | - Christopher P Saint
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia; Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
| |
Collapse
|
13
|
Carvajal G, Branch A, Sisson SA, Roser DJ, van den Akker B, Monis P, Reeve P, Keegan A, Regel R, Khan SJ. Virus removal by ultrafiltration: Understanding long-term performance change by application of Bayesian analysis. Water Res 2017; 122:269-279. [PMID: 28609730 DOI: 10.1016/j.watres.2017.05.057] [Citation(s) in RCA: 9] [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: 03/02/2017] [Revised: 05/01/2017] [Accepted: 05/28/2017] [Indexed: 05/24/2023]
Abstract
Ultrafiltration is an effective barrier to waterborne pathogens including viruses. Challenge testing is commonly used to test the inherent reliability of such systems. Performance validation seeks to demonstrate the adequate reliability of the treatment system. Appropriate and rigorous data analysis is an essential aspect of validation testing. In this study we used Bayesian analysis to assess the performance of a full-scale ultrafiltration system which was validated and revalidated after five years of operation. A hierarchical Bayesian model was used to analyse a number of similar ultrafiltration membrane skids working in parallel during the two validation periods. This approach enhanced our ability to obtain accurate estimations of performance variability, especially when the sample size of some system skids was limited. This methodology enabled the quantitative estimation of uncertainty in the performance parameters and generation of predictive distributions incorporating those uncertainties. The results indicated that there was a decrease in the mean skid performance after five years of operation of approximately 1 log reduction value (LRV). Interestingly, variability in the LRV also reduced, with standard deviations from the revalidation data being decreased by a mean 0.37 LRV compared with the original validation data. The model was also useful in comparing the operating performance of the various parallel skids within the same year. Evidence of differences was obtained in 2015 for one of the membrane skids. A hierarchical Bayesian analysis of validation data provides robust estimations of performance and the incorporation of probabilistic analysis which is increasingly important for comprehensive quantitative risk assessment purposes.
Collapse
Affiliation(s)
- Guido Carvajal
- UNSW Water Research Centre, School of Civil & Environmental Engineering, University of New South Wales, New South Wales, 2052, Australia.
| | - Amos Branch
- UNESCO Centre for Membrane Science and Technology, University of New South Wales, New South Wales, 2052, Australia.
| | - Scott A Sisson
- School of Mathematics & Statistics, University of New South Wales, New South Wales, 2052, Australia.
| | - David J Roser
- UNSW Water Research Centre, School of Civil & Environmental Engineering, University of New South Wales, New South Wales, 2052, Australia.
| | - Ben van den Akker
- Department of Environmental Health, School of Environment, Flinders University, Adelaide, South Australia, 5042, Australia; Australian Water Quality Centre, Adelaide, South Australia, 5000, Australia.
| | - Paul Monis
- South Australian Water Corporation, South Australia, 5000, Australia.
| | - Petra Reeve
- South Australian Water Corporation, South Australia, 5000, Australia.
| | - Alexandra Keegan
- South Australian Water Corporation, South Australia, 5000, Australia.
| | - Rudi Regel
- South Australian Water Corporation, South Australia, 5000, Australia.
| | - Stuart J Khan
- UNSW Water Research Centre, School of Civil & Environmental Engineering, University of New South Wales, New South Wales, 2052, Australia.
| |
Collapse
|
14
|
Thwaites BJ, Reeve P, Dinesh N, Short MD, van den Akker B. Comparison of an anaerobic feed and split anaerobic-aerobic feed on granular sludge development, performance and ecology. Chemosphere 2017; 172:408-417. [PMID: 28088532 DOI: 10.1016/j.chemosphere.2016.12.133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [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: 07/20/2016] [Revised: 12/23/2016] [Accepted: 12/27/2016] [Indexed: 06/06/2023]
Abstract
The retrofitting of existing wastewater sequencing batch reactors (SBRs) to select for rapid-settling aerobic granular sludge (AGS) over floc-based conventional activated sludge (CAS), could be a viable option to decrease reactor cycle time and increase hydraulic capacity. Successful CAS-to-AGS conversion has previously been shown to be highly dependent on having a dedicated anaerobic feed, which presents additional engineering challenges when retrofitting SBRs. In this study we compared the performance of a split anaerobic-aerobic (An-Aer) feed with that of a traditional dedicated anaerobic feed regarding AGS formation and stability, nitrogen removal performance and microbial ecology. Using pilot trials, we showed that AGS could be established and maintained when using a split An-Aer feed at low organic loading rates analogous to that of a parallel full-scale conventional SBR. Additionally, we showed that AGS start-up time and nitrogen removal performance were comparable under a split An-Aer feed and dedicated anaerobic feed. Microbial ecology characterisations based on whole-of-community 16S rRNA profiles and targeted analysis of functional genes specific for nitrifying and denitrifying microorganisms, showed that the two different feed strategies had only subtle impacts on both the overall community composition and functional ecology. A much greater divergence in microbial ecology was seen when comparing AGS with CAS. Data presented here will be of value to those planning to retrofit existing CAS-based SBRs to operate with AGS and demonstrates the viability of using a more cost-effective split An-Aer feed configuration over a dedicated anaerobic feed.
Collapse
Affiliation(s)
- Benjamin J Thwaites
- School of Civil and Environmental Engineering, University of New South Wales, Kensington, 2052, New South Wales, Australia; South Australian Water Corporation, Adelaide, 5000, South Australia, Australia.
| | - Petra Reeve
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Nirmala Dinesh
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Michael D Short
- School of Natural and Built Environments, University of South Australia, Mawson Lakes, 5095, South Australia, Australia; UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales, 2052, Australia; Future Industries Institute, University of South Australia, Mawson Lakes, 5095, South Australia, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia; School of Natural and Built Environments, University of South Australia, Mawson Lakes, 5095, South Australia, Australia; Health and Environment Group, School of the Environment, Flinders University, Bedford Park, 5042, South Australia, Australia
| |
Collapse
|
15
|
Mai L, van den Akker B, Du J, Kookana RS, Fallowfield H. Impact of exogenous organic carbon on the removal of chemicals of concern in the high rate nitrifying trickling filters. J Environ Manage 2016; 174:7-13. [PMID: 26989940 DOI: 10.1016/j.jenvman.2016.02.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 12/22/2015] [Revised: 02/26/2016] [Accepted: 02/29/2016] [Indexed: 06/05/2023]
Abstract
The application of fixed bed high rate nitrifying trickling filters (NTFs) for the removal of track organic chemicals of concern (CoC) is less well known than their application to nutrient removal in water treatment. Particularly, the effect of exogenous organic carbon substrate (sucrose) loading on the performance of NTFs is not well understood. A laboratory-scale NTF system was operated in recirculation mode, with the objective of removing ammonia and CoC simultaneously. The efficiency of a high rate NTF for removal both of low concentration of ammonia (5 mg NH4-N L(-1)) and different concentrations of CoC in the presence of an exogenous organic carbon substrate (30 mg total organic carbon (TOC) L(-1)) was investigated. In the presence of exogenous organic carbon, the results demonstrated that the high rate NTF was able to successfully remove most of the CoCs investigated, with the removal ranging from 20.2% to 87.54%. High removal efficiencies were observed for acetaminophen (87.54%), bisphenol A (86.60%), trimethoprim (86.24%) and 17α-ethynylestradiol (80.60%). It was followed by the medium removal efficiency for N, N-diethyl-m-toluamide (61.31%) and atrazine (56.90%). In contrast, the removal of caffeine (28.43%) and benzotriazole (20.20%) was poorer in the presence of exogenous organic carbon. The removal efficiency for CoC was also compared with the results obtained in our previous study in the absence of exogenous organic carbon. The results showed that the addition of exogenous organic carbon was able to improve the removal of some of the CoC. Significant TOC percentage removals (45.68%-84.43%) and ammonia removal rate (mean value of 0.44 mg NH4-N L(-1) h(-1)) were also achieved in this study. The findings from this study provide valuable information for optimising the efficiency of high rate NTF for the removal of ammonia, CoC and TOC.
Collapse
Affiliation(s)
- Lei Mai
- Department of Environmental Health, School of Environment, Flinders University, Adelaide, South Australia, 5042, Australia
| | - Ben van den Akker
- Department of Environmental Health, School of Environment, Flinders University, Adelaide, South Australia, 5042, Australia; Australian Water Quality Centre, Adelaide, South Australia, 5000, Australia
| | - Jun Du
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Land and Water, Waite Campus, Glen Osmond, South Australia, 5064, Australia
| | - Rai S Kookana
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Land and Water, Waite Campus, Glen Osmond, South Australia, 5064, Australia; University of Adelaide, Waite Campus, Glen Osmond, South Australia, 5064, Australia
| | - Howard Fallowfield
- Department of Environmental Health, School of Environment, Flinders University, Adelaide, South Australia, 5042, Australia.
| |
Collapse
|
16
|
Reeve PJ, Mouilleron I, Chuang HP, Thwaites B, Hyde K, Dinesh N, Krampe J, Lin TF, van den Akker B. Effect of feed starvation on side-stream anammox activity and key microbial populations. J Environ Manage 2016; 171:121-127. [PMID: 26861222 DOI: 10.1016/j.jenvman.2016.01.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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: 10/12/2015] [Revised: 01/25/2016] [Accepted: 01/28/2016] [Indexed: 06/05/2023]
Abstract
The anaerobic ammonium oxidation (anammox) process is widely acknowledged to be susceptible to a wide range of environmental factors given the slow growth rate of the anammox bacteria. Surprisingly there is limited experimental data regarding the susceptibility of the anammox process to feed starvations which may be encountered in full-scale applications. Therefore, a study was established to investigate the impact of feed starvations on nitritation and anammox activity in a demonstration-scale sequencing batch reactor. Three starvation periods were trialled, lasting one fortnight (15 d), one month (33 d) and two months (62 d). Regardless of the duration of the starvation period, assessment of the ammonia removal performance demonstrated nitritation and anammox activity were reinstated within one day of recovery operation. Characterisation of the community structure using 16S rRNA and functional genes specific for nitrogen-related microbes showed there was no clear impact or shift in the microbial populations between starvation and recovery phases.
Collapse
Affiliation(s)
- Petra J Reeve
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia.
| | | | - Hui-Ping Chuang
- Department of Environmental Engineering and Sustainable Environment Research Centre, National Cheng Kung University, Tainan, 70701, Taiwan
| | - Ben Thwaites
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Kylie Hyde
- Allwater JV, Adelaide, 5000, South Australia, Australia
| | - Nirmala Dinesh
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Joerg Krampe
- Institute for Water Quality, Resource and Waste Management, Vienna University of Technology, Karlsplatz, 1040, Vienna, Austria
| | - Tsair-Fuh Lin
- Department of Environmental Engineering and Sustainable Environment Research Centre, National Cheng Kung University, Tainan, 70701, Taiwan
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia; Health and Environment Group, School of the Environment, Flinders University, Bedford Park, 5042, South Australia, Australia; Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, Mawson Lakes, 5095, South Australia, Australia
| |
Collapse
|
17
|
Trinh T, van den Akker B, Coleman HM, Stuetz RM, Drewes JE, Le-Clech P, Khan SJ. Seasonal variations in fate and removal of trace organic chemical contaminants while operating a full-scale membrane bioreactor. Sci Total Environ 2016; 550:176-183. [PMID: 26815294 DOI: 10.1016/j.scitotenv.2015.12.083] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 10/16/2015] [Revised: 12/18/2015] [Accepted: 12/18/2015] [Indexed: 06/05/2023]
Abstract
Trace organic chemical (TrOC) contaminants are of concern for finished water from water recycling schemes because of their potential adverse environmental and public health effects. Understanding the impacts of seasonal variations on fate and removal of TrOCs is important for proper operation, risk assessment and management of treatment systems for water recycling such as membrane bioreactors (MBRs). Accordingly, this study investigated the fate and removal of a wide range of TrOCs through a full-scale MBR plant during summer and winter seasons. TrOCs included 12 steroidal hormones, 3 xeno-estrogens, 2 pesticides and 23 pharmaceuticals and personal care products. Seasonal differences in the mechanisms responsible for removing some of the TrOCs were evident. In particular the contribution of biotransformation and biomass adsorption to the overall removal of estrone, bisphenol A, 17β-estradiol and triclosan were consistently different between the two seasons. Substantially higher percentage removal via biotransformation was observed during the summer sampling period, which compensated for a reduction in removal attributed to biomass adsorption. The opposite was observed during winter, where the contribution of biotransformation to the overall removal of these TrOCs had decreased, which was offset by an improvement in biomass adsorption. The exact mechanisms responsible for this shift are unknown, however are likely to be temperature related as warmer temperatures can lower sorption efficiency, yet enhance biotransformation of these TrOCs.
Collapse
Affiliation(s)
- Trang Trinh
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, NSW, Australia; UNESCO Centre for Membrane Science and Technology, University of New South Wales, NSW, Australia
| | - Ben van den Akker
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, NSW, Australia
| | - Heather M Coleman
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, NSW, Australia; Nanotechnology and Integrated Bioengineering Centre, University of Ulster, Jordanstown, Northern Ireland, United Kingdom
| | - Richard M Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, NSW, Australia
| | - Jörg E Drewes
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, NSW, Australia; Chair of Urban Water Systems Engineering, Technical University of Munich, Garching/München, Germany
| | - Pierre Le-Clech
- UNESCO Centre for Membrane Science and Technology, University of New South Wales, NSW, Australia.
| | - Stuart J Khan
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, NSW, Australia
| |
Collapse
|
18
|
Pan Y, van den Akker B, Ye L, Ni BJ, Watts S, Reid K, Yuan Z. Unravelling the spatial variation of nitrous oxide emissions from a step-feed plug-flow full scale wastewater treatment plant. Sci Rep 2016; 6:20792. [PMID: 26852718 PMCID: PMC4745105 DOI: 10.1038/srep20792] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/12/2016] [Indexed: 11/09/2022] Open
Abstract
Plug-flow activated sludge reactors (ASR) that are step-feed with wastewater are widely adopted in wastewater treatment plants (WWTPs) due to their ability to maximise the use of the organic carbon in wastewater for denitrification. Nitrous oxide (N2O) emissions are expected to vary along these reactors due to pronounced spatial variations in both biomass and substrate concentrations. However, to date, no detailed studies have characterised the impact of the step-feed configuration on emission variability. Here we report on the results from a comprehensive online N2O monitoring campaign, which used multiple gas collection hoods to simultaneously measure emission along the length of a full-scale, step-fed, plug-flow ASR in Australia. The measured N2O fluxes exhibited strong spatial-temporal variation along the reactor path. The step-feed configuration had a substantial influence on the N2O emissions, where the N2O emission factors in sections following the first and second step feed were 0.68% ± 0.09% and 3.5% ± 0.49% of the nitrogen load applied to each section. The relatively high biomass-specific nitrogen loading rate in the second section of the reactor was most likely cause of the high emissions from this section.
Collapse
Affiliation(s)
- Yuting Pan
- Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia.,Department of Environmental Science and Engineering, School of Architecture and Environment, Sichuan University, Chengdu, Sichuan 610065, China
| | - Ben van den Akker
- Australian Water Quality Centre, Adelaide, 5000, South Australia, Australia.,Health and Environment Group, School of the Environment, Flinders University, Bedford Park, 5042, South Australia, Australia.,Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, Mawson Lakes, 5095, South Australia, Australia
| | - Liu Ye
- Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia.,School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane, QLD, 4072, Australia
| | - Bing-Jie Ni
- Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia
| | - Shane Watts
- Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia
| | - Katherine Reid
- Australian Water Quality Centre, Adelaide, 5000, South Australia, Australia
| | - Zhiguo Yuan
- Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia
| |
Collapse
|
19
|
Pan Y, Ye L, van den Akker B, Ganigué Pagès R, Musenze RS, Yuan Z. Sludge-Drying Lagoons: a Potential Significant Methane Source in Wastewater Treatment Plants. Environ Sci Technol 2016; 50:1368-1375. [PMID: 26642353 DOI: 10.1021/acs.est.5b04844] [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] [Indexed: 06/05/2023]
Abstract
"Sludge-drying lagoons" are a preferred sludge treatment and drying method in tropical and subtropical areas due to the low construction and operational costs. However, this method may be a potential significant source of methane (CH4) because some of the organic matter would be microbially metabolized under anaerobic conditions in the lagoon. The quantification of CH4 emissions from lagoons is difficult due to the expected temporal and spatial variations over a lagoon maturing cycle of several years. Sporadic ebullition of CH4, which cannot be easily quantified by conventional methods such as floating hoods, is also expected. In this study, a novel method based on mass balances was developed to estimate the CH4 emissions and was applied to a full-scale sludge-drying lagoon over a three year operational cycle. The results revealed that processes in a sludge-drying lagoon would emit 6.5 kg CO2-e per megaliter of treated sewage. This would represent a quarter to two-thirds of the overall greenhouse gas (GHG) emissions from wastewater-treatment plants (WWTPs). This work highlights the fact that sludge-drying lagoons are a significant source of CH4 that adds substantially to the overall GHG footprint of WWTPs despite being recognized as a cheap and energy-efficient means of drying sludge.
Collapse
Affiliation(s)
- Yuting Pan
- Department of Environmental Science and Engineering, School of Architecture and Environment, Sichuan University , Chengdu, Sichuan 610065, China
| | | | - Ben van den Akker
- Australian Water Quality Centre , Adelaide, 5000 South Australia, Australia
- Health and Environment Group, School of the Environment, Flinders University , Bedford Park, 5042 South Australia, Australia
- Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia , Mawson Lakes, 5095 South Australia, Australia
| | - Ramon Ganigué Pagès
- LEQUIA, Institute of the Environment, University of Girona , Girona, Catalonia, 17071 Spain
| | | | | |
Collapse
|
20
|
Ni BJ, Pan Y, van den Akker B, Ye L, Yuan Z. Full-Scale Modeling Explaining Large Spatial Variations of Nitrous Oxide Fluxes in a Step-Feed Plug-Flow Wastewater Treatment Reactor. Environ Sci Technol 2015; 49:9176-84. [PMID: 26153721 DOI: 10.1021/acs.est.5b02038] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nitrous oxide (N2O) emission data collected from wastewater treatment plants (WWTPs) show huge variations between plants and within one plant (both spatially and temporarily). Such variations and the relative contributions of various N2O production pathways are not fully understood. This study applied a previously established N2O model incorporating two currently known N2O production pathways by ammonia-oxidizing bacteria (AOB) (namely the AOB denitrification and the hydroxylamine pathways) and the N2O production pathway by heterotrophic denitrifiers to describe and provide insights into the large spatial variations of N2O fluxes in a step-feed full-scale activated sludge plant. The model was calibrated and validated by comparing simulation results with 40 days of N2O emission monitoring data as well as other water quality parameters from the plant. The model demonstrated that the relatively high biomass specific nitrogen loading rate in the Second Step of the reactor was responsible for the much higher N2O fluxes from this section. The results further revealed the AOB denitrification pathway decreased and the NH2OH oxidation pathway increased along the path of both Steps due to the increasing dissolved oxygen concentration. The overall N2O emission from this step-feed WWTP would be largely mitigated if 30% of the returned sludge were returned to the Second Step to reduce its biomass nitrogen loading rate.
Collapse
Affiliation(s)
- Bing-Jie Ni
- †Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Yuting Pan
- †Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Ben van den Akker
- ‡Australian Water Quality Centre, Adelaide, South Australia 5000, Australia
| | - Liu Ye
- †Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
- §School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Zhiguo Yuan
- †Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| |
Collapse
|
21
|
van den Akker B, Reid K, Middlemiss K, Krampe J. Evaluation of granular sludge for secondary treatment of saline municipal sewage. J Environ Manage 2015; 157:139-145. [PMID: 25897508 DOI: 10.1016/j.jenvman.2015.04.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [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: 01/05/2015] [Revised: 04/10/2015] [Accepted: 04/15/2015] [Indexed: 06/04/2023]
Abstract
This study examined the impact of chemical oxygen demand (COD) loading and dissolved oxygen (DO) concentration on the stability and performance of granular sludge treating high saline municipal sewage. Under high DO concentrations of 4.0-7.0 mg/L, and COD loading rates of 0.98 and 1.55 kg/m(3)/d, rapid settling granules were established within four weeks of start-up. Under the highest COD load, a reduction in DO lead to the rapid deterioration of the sludge volume index (SVI) and washout of granules due to prolific growth of the filament Thiothrix Type 021N. Conversely, when operated under a lower COD load, a reduction in DO concentration had no adverse impact on the stability of SVI and granules. A decrease in DO also improved nitrogen removal performance, where simultaneous removal of ammonium (98%), total nitrogen (86%) and BOD5 (98%) were achieved when median DO concentrations were between 1.0 and 1.5 mg/L. Phosphate removal was lower than expected, however the level of biological phosphate removal activity observed appeared sufficient to maintain granule stability, even under low DO concentrations. Nitrous oxide emissions were also characterised, which ranged between 2.3 and 6.8% of the total nitrogen load. Our results confirmed that granular sludge is a viable option for the treatment of saline sewage.
Collapse
Affiliation(s)
- Ben van den Akker
- Australian Water Quality Centre, SA Water Corporation, Adelaide, 5000 South Australia, Australia; Health and Environment Group, School of the Environment, Flinders University, Bedford Park, 5042 South Australia, Australia; Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, Mawson Lakes, 5095 South Australia, Australia.
| | - Katherine Reid
- Australian Water Quality Centre, SA Water Corporation, Adelaide, 5000 South Australia, Australia
| | - Kyra Middlemiss
- Australian Water Quality Centre, SA Water Corporation, Adelaide, 5000 South Australia, Australia
| | - Joerg Krampe
- Institute for Water Quality, Resource and Waste Management, Vienna University of Technology, Karlsplatz, 1040 Vienna, Austria
| |
Collapse
|
22
|
van den Akker B, Trinh T, Coleman HM, Stuetz RM, Le-Clech P, Khan SJ. Validation of a full-scale membrane bioreactor and the impact of membrane cleaning on the removal of microbial indicators. Bioresour Technol 2014; 155:432-437. [PMID: 24456851 DOI: 10.1016/j.biortech.2013.12.123] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [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: 11/20/2013] [Revised: 12/23/2013] [Accepted: 12/28/2013] [Indexed: 06/03/2023]
Abstract
The removal of microbial indicators through a full-scale membrane bioreactor (MBR) was characterised. The overall log reduction of Escherichia coli and total coliforms were in the range of 5.0-5.9log10 units, while the reduction of clostridia was marginally less at 4.9log10 units. Removal of bacteriophage was in excess of 4.6log10 units. The impact of membrane cleaning on the elimination of microbial indicators was also assessed since this had been identified by pilot-scale studies as a potential hazardous event. Membrane cleaning temporarily reduced the log removal values of E. coli and total coliforms each by 1log10 unit, but did not affect the removal of bacteriophage or clostridia. Very little research has previously examined the consequences of hazardous events on the performance of full-scale MBRs, and thus the findings presented here will facilitate improvements for the risk assessment and management of MBRs used in water recycling schemes.
Collapse
Affiliation(s)
- Ben van den Akker
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, NSW, Australia.
| | - Trang Trinh
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, NSW, Australia
| | - Heather M Coleman
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, NSW, Australia
| | - Richard M Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, NSW, Australia
| | - Pierre Le-Clech
- UNESCO Centre for Membrane Science and Technology, School of Chemical Engineering, The University of New South Wales, NSW, Australia
| | - Stuart J Khan
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, NSW, Australia
| |
Collapse
|
23
|
Whiley H, van den Akker B, Giglio S, Bentham R. The role of environmental reservoirs in human campylobacteriosis. Int J Environ Res Public Health 2013; 10:5886-907. [PMID: 24217177 PMCID: PMC3863877 DOI: 10.3390/ijerph10115886] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 10/16/2013] [Accepted: 10/28/2013] [Indexed: 11/17/2022]
Abstract
Campylobacteriosis is infection caused by the bacteria Campylobacter spp. and is considered a major public health concern. Campylobacter spp. have been identified as one of the most common causative agents of bacterial gastroenteritis. They are typically considered a foodborne pathogen and have been shown to colonise the intestinal mucosa of all food-producing animals. Much emphasis has been placed on controlling the foodborne pathway of exposure, particularly within the poultry industry, however, other environmental sources have been identified as important contributors to human infection. This paper aims to review the current literature on the sources of human exposure to Campylobacter spp. and will cover contaminated poultry, red meat, unpasteurised milk, unwashed fruit and vegetables, compost, wild bird faeces, sewage, surface water, ground water and drinking water. A comparison of current Campylobacter spp. identification methods from environmental samples is also presented. The review of literature suggests that there are multiple and diverse sources for Campylobacter infection. Many environmental sources result in direct human exposure but also in contamination of the food processing industry. This review provides useful information for risk assessment.
Collapse
Affiliation(s)
- Harriet Whiley
- Environmental Health, School of the Environment, Flinders University, P.O. Box 2100, Adelaide 5001, South Australia, Australia; E-Mail:
| | - Ben van den Akker
- School of Chemical Engineering, The University of Adelaide, Adelaide 5001, South Australia, Australia; E-Mail:
| | - Steven Giglio
- Healthscope Pathology, South Australia, 1 Goodwood Rd., Wayville 5034, South Australia, Australia; E-Mail:
| | - Richard Bentham
- Environmental Health, School of the Environment, Flinders University, P.O. Box 2100, Adelaide 5001, South Australia, Australia; E-Mail:
| |
Collapse
|
24
|
Short MD, Abell GCJ, Bodrossy L, van den Akker B. Application of a novel functional gene microarray to probe the functional ecology of ammonia oxidation in nitrifying activated sludge. PLoS One 2013; 8:e77139. [PMID: 24155925 PMCID: PMC3796556 DOI: 10.1371/journal.pone.0077139] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 08/30/2013] [Indexed: 11/30/2022] Open
Abstract
We report on the first study trialling a newly-developed, functional gene microarray (FGA) for characterising bacterial and archaeal ammonia oxidisers in activated sludge. Mixed liquor (ML) and media biofilm samples from a full-scale integrated fixed-film activated sludge (IFAS) plant were analysed with the FGA to profile the diversity and relative abundance of ammonia-oxidising archaea and bacteria (AOA and AOB respectively). FGA analyses of AOA and AOB communities revealed ubiquitous distribution of AOA across all samples – an important finding for these newly-discovered and poorly characterised organisms. Results also revealed striking differences in the functional ecology of attached versus suspended communities within the IFAS reactor. Quantitative assessment of AOB and AOA functional gene abundance revealed a dominance of AOB in the ML and approximately equal distribution of AOA and AOB in the media-attached biofilm. Subsequent correlations of functional gene abundance data with key water quality parameters suggested an important functional role for media-attached AOB in particular for IFAS reactor nitrification performance and indicate possible functional redundancy in some IFAS ammonia oxidiser communities. Results from this investigation demonstrate the capacity of the FGA to resolve subtle ecological shifts in key microbial communities in nitrifying activated sludge and indicate its value as a tool for better understanding the linkages between the ecology and performance of these engineered systems.
Collapse
Affiliation(s)
- Michael D. Short
- UNSW Water Research Centre, School of Civil and Environmental Engineering, the University of New South Wales, Kensington, New South Wales, Australia
- SA Water Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, Adelaide, South Australia, Australia
| | - Guy C. J. Abell
- CSIRO Marine and Atmospheric Research and Wealth from Oceans National Research Flagship, Hobart, Tasmania, Australia
- * E-mail:
| | - Levente Bodrossy
- CSIRO Marine and Atmospheric Research and Wealth from Oceans National Research Flagship, Hobart, Tasmania, Australia
| | - Ben van den Akker
- UNSW Water Research Centre, School of Civil and Environmental Engineering, the University of New South Wales, Kensington, New South Wales, Australia
| |
Collapse
|
25
|
Abstract
Despite routine monitoring and disinfection, treated swimming pools are frequently contaminated with the opportunistic pathogen Pseudomonas aeruginosa, which can represent a significant public health threat. This review was undertaken to identify the current understanding of risk factors associated with pool operation with respect to P. aeruginosa. The ecology and factors that promote growth of P. aeruginosa in the pool environment are complex and dynamic and so we applied a systematic risk assessment approach to integrate existing data, with the aim to improve pool management and safety. Sources of P. aeruginosa, types of infections, dose responses, routes of transmission, as well as the efficacy of current disinfectant treatments were reviewed. This review also highlights the critical knowledge gaps that are required for a more robust, quantitative risk assessment of P. aeruginosa. Quantitative risk management strategies have been successfully applied to drinking water systems and should similarly be amenable to developing a better understanding of the risk posed by P. aeruginosa in swimming pools.
Collapse
Affiliation(s)
- Scott A Rice
- The School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia.
| | | | | | | |
Collapse
|
26
|
van den Akker B, Holmes M, Pearce P, Cromar NJ, Fallowfield HJ. Structure of nitrifying biofilms in a high-rate trickling filter designed for potable water pre-treatment. Water Res 2011; 45:3489-3498. [PMID: 21543100 DOI: 10.1016/j.watres.2011.04.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 03/02/2011] [Accepted: 04/11/2011] [Indexed: 05/30/2023]
Abstract
This study examined the composition and structure of nitrifying biofilms sampled from a high-rate nitrifying trickling filter which was designed to pre-treat raw surface water for potable supply. The filter was operated under a range of feed water ammonia and organic carbon concentrations that mimicked the raw water quality of poorly protected catchments. The biofilm structure was examined using a combination of fluorescence in situ hybridisation and scanning electron microscopy. Biopolymers (carbohydrate and protein) were also measured. When the filter was operated under low organic loads, nitrifiers were abundant, representing the majority of microorganisms present. Uniquely, the study identified not only Nitrospira but also the less common Nitrobacter. Small increases in organic carbon promoted the rapid growth of filamentous heterotrophs, as well as the production of large amounts of polysaccharide. Stratification of nitrifiers and heterotrophs, and high polysaccharide were observed at all filter bed depths, which coincided with the impediment of nitrification throughout most of the filter bed. Observations presented here specifically linked biofilm structure with filter functionality, physically validating previous empirical modelling hypotheses regarding competitive interactions between autotrophic and heterotrophic bacteria in biofilms.
Collapse
Affiliation(s)
- Ben van den Akker
- Health and Environment Group, School of Environment, Flinders University, Bedford Park, South Australia 5042, Australia.
| | | | | | | | | |
Collapse
|
27
|
van den Akker B, Beard H, Kaeding U, Giglio S, Short MD. Exploring the relationship between viscous bulking and ammonia-oxidiser abundance in activated sludge: A comparison of conventional and IFAS systems. Water Res 2010; 44:2919-2929. [PMID: 20202664 DOI: 10.1016/j.watres.2010.02.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 02/01/2010] [Accepted: 02/10/2010] [Indexed: 05/28/2023]
Abstract
This study investigated the nature of viscous sludge bulking within a molasses-fed integrated fixed-film activated sludge (IFAS) and conventional activated sludge (AS) plant by routinely measuring the total carbohydrate and protein fractions of the mixed liquor (ML). The impacts of sludge settleability and plant performance on the relative abundance of ammonia-oxidising bacteria (AOB) (Nitrosomonas oligotropha-cluster) were also investigated using quantitative polymerase chain reaction (qPCR). Results showed that sludge volume index (SVI) correlated positively with the amount of ML total carbohydrate in both the IFAS and traditional AS plants, highlighting the influential role that ML polysaccharide concentration plays on sludge settleability in these reactors. Results also revealed a negative relationship between the AOB/total Bacteria ratio and SVI, demonstrating that a poor settling sludge generally coincided with periods of relatively low AOB abundance. The existence of these relationships suggests that readily available organic carbon (molasses) was likely to have been present in excess in these systems. Our qPCR results also showed that concentrations of both AOB and total Bacteria genomic copies detected within the ML of the IFAS and conventional AS plants were remarkably similar. For the IFAS system, results showed that the ML supported an equivalent number of AOB (per gram of biomass) to that detected on the plastic IFAS media carriers, suggesting that the suspended biomass fraction plays an equally important role in the overall nitrification performance of these systems. Interestingly, large observed variations in AOB and AOB/total Bacteria ratio measured within both the ML and IFAS media carriers had no measurable impact on the apparent nitrification performance of these systems; indicating the presence of some excess or 'reserve' nitrifying capacity above that which is required for effective plant performance. Results presented here also constitute the first known side-by-side comparison of the distribution of AOB in IFAS and conventional racetrack-like AS plants at the full-scale level.
Collapse
Affiliation(s)
- Ben van den Akker
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
| | | | | | | | | |
Collapse
|
28
|
Klein M, Brown L, van den Akker B, Peters GM, Stuetz RM, Roser DJ. Monitoring bacterial indicators and pathogens in cattle feedlot waste by real-time PCR. Water Res 2010; 44:1381-1388. [PMID: 19939430 DOI: 10.1016/j.watres.2009.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 11/10/2009] [Accepted: 11/10/2009] [Indexed: 05/28/2023]
Abstract
Quantitative microbial health risk assessment requires accurate enumeration of pathogens in hazard-containing matrices as part of the risk characterization process. As part of a risk management-oriented study of cattle feedlot waste contaminants, we investigated the utility of quantitative real-time PCR (qPCR) for surveying the microbial constituents of different faecal wastes. The abundance of Escherichia coli and enterococci were first estimated in five cattle feedlot waste types from five localities. Bacteria were quantified using two culture methods and compared to the number of genome copies detected by qPCR targeted at E. coli and Enterococcus faecalis. Bacterial numbers detected in the different wastes (fresh faeces, pen manure, aged manure, composted manure, carcass manure compost) ranged from 10-(7) to 10(2)g(-1) (dry weight). Both indicator groups were detected by qPCR with a comparable sensitivity to culture methods across this range. qPCR measurements of E. coli and E. faecalis correlated well with MPN and spread plate data. As a second comparison, we inoculated green fluorescent protein (GFP) labeled reference bacteria into manure samples. GFP labeled E. coli and Listeria monocytogenes were detected by qPCR in concentrations corresponding to between 18% and 71% of the initial bacterial numbers, compared to only 2.5-16% by plating. Our results supported our selection of qPCR as a fast, accurate and reliable system for surveying the presence and abundance of pathogens in cattle waste.
Collapse
Affiliation(s)
- Marcus Klein
- School of Civil and Environmental Engineering, UNSW Water Research Centre, University of New South Wales, NSW 2052, Australia.
| | | | | | | | | | | |
Collapse
|
29
|
van den Akker B, Holmes M, Cromar N, Fallowfield H. The impact of organic carbon on the performance of a high rate nitrifying trickling filter designed to pre-treat potable water. Water Sci Technol 2010; 61:1875-1883. [PMID: 20371947 DOI: 10.2166/wst.2010.358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The application of nitrifying trickling filters (NTFs) to potable water treatment is less well understood than their application to wastewater treatment, particularly regarding the effect of low ammonia substrate concentrations and organic carbon loading on filter performance. A large pilot-scale NTF was operated under conditions that simulated the raw water quality of poorly protected catchments typically found in SE Asia, with the objective of reducing the ammonia driven chlorine demand during disinfection. The efficacy of a high rate NTF to remove low concentrations of ammonia (0.5-5.0 mg NH(4)-N L(-1)) in the presence of high organic carbon (1-12 mg soluble biochemical oxygen demand (sBOD(5)) L(-1)) was investigated. Results demonstrated that 90 to 100% of nitrification was maintained only when the carbon load was less than 0.7 g sBOD(5) m(-2) d(-1) (<4 mg sBOD(5) L(-1)). Once the organic load was increased beyond 0.75 to 2.1 g sBOD(5) m(-2) d(-1) (4.5-12.1 mg sBOD(5) L(-1)), a linear decline in nitrification from 70 to 15% was observed within a timeframe of 8 to 10 d. The impact of high organic loads on the distribution of nitrification down the NTF was also investigated. Results confirmed that carbon loads greater than 0.95 g sBOD(5) m(-2) d(-1) (>5.5 mg sBOD(5) L(-1)), severely suppressed nitrification throughout the entire filter bed.
Collapse
Affiliation(s)
- Ben van den Akker
- Department of Environmental Health & Flinders Research Centre for Coastal and Catchment Environments, Flinders University, Bedford Park, South Australia 5042, Australia.
| | | | | | | |
Collapse
|
30
|
van den Akker B, Holmes M, Cromar N, Fallowfield H. Application of high rate nitrifying trickling filters for potable water treatment. Water Res 2008; 42:4514-4524. [PMID: 18752823 DOI: 10.1016/j.watres.2008.07.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 07/27/2008] [Accepted: 07/30/2008] [Indexed: 05/26/2023]
Abstract
The interference of ammonia with chlorination is a prevalent problem encountered by water treatment plants located throughout South East Asia. The efficacy of high rate, plastic-packed trickling filters as a pre-treatment process to remove low concentrations of ammonia from polluted surface water was investigated. This paper presents the findings from a series of pilot experiments, which were designed to investigate the effect of specific conditions-namely low ammonia feed concentrations (0.5-5.0 mg NH(4)-NL(-1)), variations in hydraulic surface load (72.5-145 m(3)m(-2)d(-1)) and high suspended solid loads (51+/-25 mgL(-1))-on filter nitrifying capacity. The distribution of nitrification activity throughout a trickling filter bed was also characterised. Results confirmed that high hydraulic rate trickling filters were able to operate successfully, under ammonia-N concentrations some 10- to 50-fold lower and at hydraulic loading rates 30-100 times greater than those of conventional wastewater applications. Mass transport limitations posed by low ammonia-N concentrations on overall filter performance were insignificant, where apparent nitrification rates (0.4-1.6 g NH(4)-Nm(-2)d(-1)), equivalent to that of wastewater filters were recorded. High inert suspended solid loadings had no adverse effect on nitrification. Results imply that implementation of high rate trickling filters at the front-end of a water treatment train would reduce the ammonia-related chlorine demand, thereby offering significant cost savings.
Collapse
Affiliation(s)
- Ben van den Akker
- Department of Environmental Health and Flinders Research Centre for Coastal and Catchment Environments, Flinders University, Bedford Park, South Australia, Australia.
| | | | | | | |
Collapse
|