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North D, Bibby K. Comparison of viral concentration techniques for native fecal indicators and pathogens from wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167190. [PMID: 37741389 DOI: 10.1016/j.scitotenv.2023.167190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/12/2023] [Accepted: 09/16/2023] [Indexed: 09/25/2023]
Abstract
Viral pathogens are typically dilute in environmental waters, necessitating a concentration step prior to subsequent quantification or analysis. Historically, studies on viral concentration efficiency have been done by spiking known viruses into the sample; however, spike-in controls may not have the same behavior as "native" viruses exposed to environmental conditions. In this study, four concentration methods, including polyethylene glycol precipitation (PEG), skimmed milk flocculation (SMF), pH drop followed by filtration through a 0.45 μm filter (pH), and centrifugation using an Amicon filter (Amicon), were evaluated to concentrate native viral targets in wastewater. Viral targets included both indicators (crAssphage and pepper mild mottle virus) and pathogens (adenovirus, norovirus GII, human polyomavirus, and SARS-CoV-2) in addition to a bacterial marker (HF183). A non-native spike-in control was also added to compare native and spike-in recoveries. Recovery varied widely across targets and methods, ranging from 0.1 to 39.3 %. The Amicon method was the most broadly effective concentration for recovery efficiency. For the lowest-titer target, the PEG method resulted in the lowest number of non-detections, with 96.7 % positive detections for SARS-CoV-2, compared to 66.7 %, 80 %, and 76.7 % positive detections for SMF, pH, and Amicon, respectively. The non-native spike-ins chosen were only representative of a few native recovery trends, varying by both target and concentration method, and consistently under or over-estimated recovery. Overall, this study suggests the utility of including native targets in viral concentration evaluation and determining the efficiency of concentration methods for a specific target of interest.
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Affiliation(s)
- Devin North
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556, United States
| | - Kyle Bibby
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556, United States.
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Valdez FQ, Leite LDS, Zanetoni Filho JA, Tango MD, Daniel LA. Detection and removal of Giardia spp. cysts and Cryptosporidium spp. oocysts by anaerobic reactors in Brazil. ENVIRONMENTAL TECHNOLOGY 2022; 43:2059-2068. [PMID: 33334260 DOI: 10.1080/09593330.2020.1866083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
The discharge of raw wastewater into the environment can be a contamination source of Giardia spp. cysts and Cryptosporidium spp. oocysts. The UASB (Upflow Anaerobic Sludge Blanket) reactor is the most popular technology applied for wastewater treatment in Brazil, nevertheless there is little information concerning its capacity for (oo)cyst removal. In this context, this study investigated the occurrence and removal of Giardia spp. cysts and Cryptosporidium spp. oocysts by three different UASB reactors (i.e. Reactor A, B, and C) treating different wastewater types. In the wastewater influent, the concentration varied from 493.3 to 14,000 cysts·L-1 for Giardia spp. and from 'not detected' to 53.3 oocysts·L-1 for Cryptosporidium spp.. The (oo)cyst concentration increased after the anaerobic treatment in Reactors A and B, while Giardia spp. log-removal of 0.5 ± 0.2 was found in Reactor C. The increment in (oo)cyst concentration may happened due to the inefficacy for (oo)cyst removal by the specific UASB reactor and/or due to the reduction of matrix interference for reactor effluent samples in the detection method. The results suggest that hydraulic retention time (HRT) may be the key parameter for Giardia spp. removal by the UASB reactor. Furthermore, no parameter analysed (physical-chemical and indicator microorganisms) showed a common correlation with the (oo)cyst concentration in the three UASB reactors. Considering that official data of cryptosporidiosis and giardiasis cases are rarely reported in Brazil, monitoring Giardia spp. cysts and Cryptosporidium spp. oocysts in wastewater could be an alternative to estimate the occurrence of diseases in the served population.
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Affiliation(s)
- Fernanda Queiroz Valdez
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, São Carlos, Brazil
| | - Luan de Souza Leite
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, São Carlos, Brazil
| | - José Antônio Zanetoni Filho
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, São Carlos, Brazil
| | - Mariana Daniel Tango
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, São Carlos, Brazil
| | - Luiz Antonio Daniel
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, São Carlos, Brazil
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Medeiros RC, Sammarro Silva KJ, Daniel LA. Wastewater treatment performance in microbiological removal and (oo)cyst viability assessed comparatively to fluorescence decay. ENVIRONMENTAL TECHNOLOGY 2022; 43:962-970. [PMID: 32799634 DOI: 10.1080/09593330.2020.1811396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Municipal wastewater is a source of pathogenic protozoan (oo)cysts and may play a significant role in spreading waterborne diseases. This scenario becomes more critical as treated sewage from municipal wastewater treatment plants (WWTP) is discharged into springs, which are often used for water supply, irrigation, recreation and, further downstream, indirect potable reuse, quite common in Brazil. This study aimed to elucidate, regarding microbiological quality, the performance of a full-scale WWTP, consisting of preliminary treatment, upflow anaerobic sludge blanket (UASB) reactor, activated sludge system and ultraviolet (UV) radiation disinfection. Pathogenic protozoa (Giardia spp. cysts and Cryptosporidium spp. oocysts), as well as microbiological indicators (Escherichia coli and Clostridium perfringens), were evaluated in terms of their removal. In addition, (oo)cyst viability and fluorescence reduction were assessed. By using the data obtained from this research, the prevalence of infection estimated for the population served by the WWTP was between 7.4% and 14.8% for giardiasis, and between 0.055% and 0.11% for cryptosporidiosis.
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Affiliation(s)
- Raphael Corrêa Medeiros
- Department of Engineering and Environmental Technology, Federal University of Santa Maria - campus Frederico Westphalen, Rio Grande do Sul, Brazil
| | - Kamila Jessie Sammarro Silva
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, São Paulo, Brazil
| | - Luiz Antonio Daniel
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, São Paulo, Brazil
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4
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Kevill JL, Pellett C, Farkas K, Brown MR, Bassano I, Denise H, McDonald JE, Malham SK, Porter J, Warren J, Evens NP, Paterson S, Singer AC, Jones DL. A comparison of precipitation and filtration-based SARS-CoV-2 recovery methods and the influence of temperature, turbidity, and surfactant load in urban wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:151916. [PMID: 34826466 PMCID: PMC8610557 DOI: 10.1016/j.scitotenv.2021.151916] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/09/2021] [Accepted: 11/19/2021] [Indexed: 05/09/2023]
Abstract
Wastewater-based epidemiology (WBE) has become a complimentary surveillance tool during the SARS-CoV-2 pandemic. Viral concentration methods from wastewater are still being optimised and compared, whilst viral recovery under different wastewater characteristics and storage temperatures remains poorly understood. Using urban wastewater samples, we tested three viral concentration methods; polyethylene glycol precipitation (PEG), ammonium sulphate precipitation (AS), and CP select™ InnovaPrep® (IP) ultrafiltration. We found no major difference in SARS-CoV-2 and faecal indicator virus (crAssphage) recovery from wastewater samples (n = 46) using these methods, PEG slightly (albeit non-significantly), outperformed AS and IP for SARS-CoV-2 detection, as a higher genome copies per litre (gc/l) was recorded for a larger proportion of samples. Next generation sequencing of 8 paired samples revealed non-significant differences in the quality of data between AS and IP, though IP data quality was slightly better and less variable. A controlled experiment assessed the impact of wastewater suspended solids (turbidity; 0-400 NTU), surfactant load (0-200 mg/l), and storage temperature (5-20 °C) on viral recovery using the AS and IP methods. SARS-CoV-2 recoveries were >20% with AS and <10% with IP in turbid samples, whilst viral recoveries for samples with additional surfactant were between 0-18% for AS and 0-5% for IP. Turbidity and sample storage temperature combined had no significant effect on SARS-CoV-2 recovery (p > 0.05), whilst surfactant and storage temperature combined were significant negative correlates (p < 0.001 and p < 0.05, respectively). In conclusion, our results show that choice of methodology had small effect on viral recovery of SARS-CoV-2 and crAssphage in wastewater samples within this study. In contrast, sample turbidity, storage temperature, and surfactant load did affect viral recovery, highlighting the need for careful consideration of the viral concentration methodology used when working with wastewater samples.
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Affiliation(s)
- Jessica L Kevill
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK.
| | - Cameron Pellett
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Kata Farkas
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK; School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK
| | - Mathew R Brown
- Joint Biosecurity Centre, Department of Health and Social Care, London WC1B 4DA, UK; School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Irene Bassano
- Joint Biosecurity Centre, Department of Health and Social Care, London WC1B 4DA, UK; Department of Infectious Disease, Imperial College London, London SW7 2AZ, UK
| | - Hubert Denise
- Joint Biosecurity Centre, Department of Health and Social Care, London WC1B 4DA, UK
| | - James E McDonald
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Shelagh K Malham
- School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK
| | - Jonathan Porter
- Environment Agency National Laboratory Service, Exeter, Devon EX6 8PE, UK
| | - Jonathan Warren
- Environment Agency National Laboratory Service, Exeter, Devon EX6 8PE, UK
| | - Nicholas P Evens
- Environment Agency National Laboratory Service, Exeter, Devon EX6 8PE, UK
| | - Steve Paterson
- Centre of Genomics Research & NERC Environmental Omics Facility, University of Liverpool, Liverpool L69 7ZB, UK
| | | | - Davey L Jones
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK; Food Futures Institute, Murdoch University, 90 South Street, Murdoch, WA 6105, Australia
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Fava NDMN, Silva KJS, Snelling WJ, Ternan NG, Dooley JSG, Sabogal-Paz LP. Does each bead count? A reduced-cost approach for recovering waterborne protozoa from challenge water using immunomagnetic separation. JOURNAL OF WATER AND HEALTH 2021; 19:436-447. [PMID: 34152296 DOI: 10.2166/wh.2021.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Giardia duodenalis and Cryptosporidium spp. are two of the most prominent aetiological agents of waterborne diseases. Therefore, efficient and affordable methodologies for identifying and quantifying these parasites in water are increasingly necessary. USEPA Method 1623.1 is a widely used and validated protocol for detecting these parasites in water samples. It consists of a concentration step, followed by parasite purification and visualization by immunofluorescence microscopy. Although efficient, this method has a high cost particularly due to the immunomagnetic separation (IMS) step, which is most needed with complex and highly contaminated samples. Based on this, the present study aimed to determine whether it is possible to maintain the efficiency of Method 1623.1 while reducing the amount of beads per reaction, using as a matrix the challenge water recommended by the World Health Organization. As for Giardia cysts, a satisfactory recovery efficiency (RE) was obtained using 50% less IMS beads. This was evaluated both with a commercial cyst suspension (56.1% recovery) and an analytical quality assessment (47.5% recovery). Although RE rates obtained for Cryptosporidium parvum did not meet Method 1623.1 criteria in any of the experimental conditions tested, results presented in this paper indicated the relevance of the described adaptations, even in challenge water.
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Affiliation(s)
- Natália de Melo Nasser Fava
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, São Carlos, São Paulo 13566-590, Brazil E-mail:
| | - Kamila Jessie Sammarro Silva
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, São Carlos, São Paulo 13566-590, Brazil E-mail:
| | - William John Snelling
- Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Coleraine BT52 1SA, UK
| | - Nigel George Ternan
- Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Coleraine BT52 1SA, UK
| | - James Stephen Gerard Dooley
- Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Coleraine BT52 1SA, UK
| | - Lyda Patricia Sabogal-Paz
- Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, São Carlos, São Paulo 13566-590, Brazil E-mail:
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de Oliveira GL, Daniel LA. Removal of Giardia spp. cysts and Cryptosporididum spp. oocysts from anaerobic effluent by dissolved air flotation. ENVIRONMENTAL TECHNOLOGY 2021; 42:141-147. [PMID: 31136251 DOI: 10.1080/09593330.2019.1625447] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
Lab-scale studies were carried out to investigate the efficiency of dissolved air flotation (DAF) for the removal of Giardia spp. cysts and Cryptosporidium spp. oocysts from anaerobic effluent from the pilot UASB reactor. Raw wastewater, UASB and DAF effluent samples were collected weekly and protozoan (oo)cysts were concentrated using IMS followed by protozoa detection using immunofluorescense assay (IFA). The number of Cryptosporidium spp. oocysts in the raw wastewater was always lower than that of Giardia spp. cysts with 28-33 oocysts L-1 and 3177-4267 cysts L-1, respectively. Log10 removal of Giardia cysts utilising polyaluminium chloride (PACl) was higher than that with FeCl3, but no statistically significant difference between the two coagulants was observed. Cryptosporidium was absent in most of the treated effluent samples. The results indicate that DAF reached more than 2 log of cyst removal. In addition, the results demonstrated that these parasites are prevalent in the study area and E. coli and total coliforms were not good indicator microorganisms in terms of cyst and oocysts numbers.
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Affiliation(s)
- Gabriela Laila de Oliveira
- Hydraulic and Sanitation Department, São Carlos School of Engineering, University of São Paulo, São Paulo, Brazil
| | - Luiz Antonio Daniel
- Hydraulic and Sanitation Department, São Carlos School of Engineering, University of São Paulo, São Paulo, Brazil
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Shrestha R, Duwal R, Wagle S, Pokhrel S, Giri B, Neupane BB. A smartphone microscopic method for simultaneous detection of (oo)cysts of Cryptosporidium and Giardia. PLoS Negl Trop Dis 2020; 14:e0008560. [PMID: 32898180 PMCID: PMC7500626 DOI: 10.1371/journal.pntd.0008560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 09/18/2020] [Accepted: 07/04/2020] [Indexed: 01/09/2023] Open
Abstract
Background Food and water-borne illness caused by ingestion of (oo)cysts of Cryptosporidium and Giardia is one of the major health problems globally. Several methods are available to detect Giardia cyst and Cryptosporidium oocyst in food and water. Most of the available methods require a good laboratory facility and well-trained manpower and are therefore costly. There is a need of affordable and reliable method that can be easily implemented in resource limited settings. Methodology/Principle findings We developed a smartphone based microscopic assay method to screen (oo)cysts of Cryptosporidium and Giardia contamination of vegetable and water samples. The method consisting of a ball lens of 1 mm diameter, white LED as illumination source and Lugols's iodine staining provided magnification and contrast capable of distinguishing (oo)cysts of Cryptosporidium and Giardia. The analytical performance of the method was tested by spike recovery experiments. The spike recovery experiments performed on cabbage, carrot, cucumber, radish, tomatoes, and water resulted in 26.8±10.3, 40.1±8.5, 44.4±7.3, 47.6±11.3, 49.2 ±10.9, and 30.2±7.9% recovery for Cryptosporidium, respectively and 10.2±4.0, 14.1±7.3, 24.2±12.1, 23.2±13.7, 17.1±13.9, and 37.6±2.4% recovery for Giardia, respectively. The spike recovery results are comparable with data obtained using commercial brightfield and fluorescence microscope methods. Finally, we tested the smartphone microscope system for detecting (oo)cysts on 7 types of vegetable (n = 196) and river water (n = 18) samples. Forty-two percent vegetable and thirty-nine percent water samples were found to be contaminated with Cryptosporidium oocyst. Similarly, thirty-one percent vegetable and thirty-three percent water samples were contaminated with Giardia cyst. Conclusions The newly developed smartphone microscopic method showed comparable performance to commercial microscopic methods. The new method can be a low-cost and easy to implement alternative method for simultaneous detection of (oo)cysts in vegetable and water samples in resource limited settings. Food and water-borne illness arising from the consumption of contaminated food and water are serious health hazards globally. Cryptosporidium and Giardia are the major food and water‒borne parasites. The infection occurs mainly by (oo)cyst phase of the parasites. People in developing countries are more vulnerable to these parasites where infection is more likely underdiagnosed and underreported due to limited resources for detection. There is need of a method that is affordable and easy to implement. In this study, we developed and optimized a novel smartphone microscope method that can detect and quantify the (oo)cyst of the parasites in food and water samples. The developed method is easy to implement and affordable and provides similar performance to the other commercially available microscopic methods.
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Affiliation(s)
- Retina Shrestha
- Center for analytical sciences, Kathmandu Institute of Applied Sciences, Kathmandu, Nepal
| | - Rojina Duwal
- Center for analytical sciences, Kathmandu Institute of Applied Sciences, Kathmandu, Nepal
| | - Sajeev Wagle
- Center for analytical sciences, Kathmandu Institute of Applied Sciences, Kathmandu, Nepal
| | - Samiksha Pokhrel
- Center for analytical sciences, Kathmandu Institute of Applied Sciences, Kathmandu, Nepal
- Department of Environmental Science, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal
| | - Basant Giri
- Center for analytical sciences, Kathmandu Institute of Applied Sciences, Kathmandu, Nepal
- * E-mail: (BG); (BBN)
| | - Bhanu Bhakta Neupane
- Center for analytical sciences, Kathmandu Institute of Applied Sciences, Kathmandu, Nepal
- Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal
- * E-mail: (BG); (BBN)
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Medeiros RC, Daniel LA, de Oliveira GL, Hoffmann MT. Performance of a small-scale wastewater treatment plant for removal of pathogenic protozoa (oo)cysts and indicator microorganisms. ENVIRONMENTAL TECHNOLOGY 2019; 40:3492-3501. [PMID: 29813004 DOI: 10.1080/09593330.2018.1480063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/10/2018] [Indexed: 06/08/2023]
Abstract
The protozoa Giardia and Cryptosporidium are associated with numerous outbreaks of waterborne diseases worldwide. This study aimed to evaluate the concentration of Giardia spp. cysts, Cryptosporidium spp. oocysts, total coliforms, Escherichia coli and Clostridium perfringens in raw wastewater and their removals at UASB reactor, activated sludge system (operated conventionally and extended aeration) and slow sand filtration. Giardia spp. cysts were present in 100% and Cryptosporidium spp. oocysts in 31.4% of the analysed wastewater samples. The UASB reactor followed by activated sludge system obtained approximately 2.0 log of removal for total coliforms and E. coli, whereas for C. perfringens and Giardia spp. cysts, it obtained 1 log. There was a high percentage of (oo)cysts still viable after secondary treatment, therefore, the risk of contamination of water courses and, consequently, for public health is considerable. However, after tertiary filtration, no (oo)cysts were found in any of the filtered effluent samples, being a good option for future reuse. Seasonal variations did not affect the concentrations and removals of microorganisms observed. Lack of correlations of concentrations of indicator microorganisms and (oo)cysts raise caveats and doubts regarding the true microbiological quality when using only indicator microorganisms.
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Affiliation(s)
- Raphael Corrêa Medeiros
- Department of Engineering and Environmental Technology, Federal University of Santa Maria , Frederico Westphalen , Brazil
| | - Luiz Antonio Daniel
- Hydraulics and Sanitation Department, São Carlos School of Engineering, University of São Paulo , São Carlos - São Paulo , Brazil
| | - Gabriela Laila de Oliveira
- Hydraulics and Sanitation Department, São Carlos School of Engineering, University of São Paulo , São Carlos - São Paulo , Brazil
| | - Maria Teresa Hoffmann
- Hydraulics and Sanitation Department, São Carlos School of Engineering, University of São Paulo , São Carlos - São Paulo , Brazil
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Slompo NDM, Quartaroli L, Zeeman G, da Silva GHR, Daniel LA. Black water treatment by an upflow anaerobic sludge blanket (UASB) reactor: a pilot study. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2019; 80:1505-1511. [PMID: 31961813 DOI: 10.2166/wst.2019.402] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Decentralized sanitary wastewater treatment has become a viable and sustainable alternative, especially for developing countries and small communities. Besides, effluents may present variations in chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total nitrogen values. This study describes the feasibility of using a pilot upflow anaerobic sludge blanket (UASB) reactor to treat wastewater with different organic loads (COD), using black water (BW) and sanitary wastewater, in addition to its potential for preserving nutrients for later recovery and/or reuse. The UASB reactor was operated continuously for 95 weeks, with a hydraulic retention time of 3 days. In Phase 1, the reactor treated simulated BW and achieved 77% CODtotal removal. In Phase 2, treating only sanitary wastewater, the CODtotal removal efficiency was 60%. Phase 3 treated simulated BW again, and CODtotal removal efficiency was somewhat higher than in Phase 1, reaching 81%. In Phase 3, the removal of pathogens was also evaluated: the efficiency was 1.96 log for Escherichia coli and 2.13 log for total coliforms. The UASB reactor was able to withstand large variations in the organic loading rate (0.09-1.49 kg COD m-3 d-1), in continuous operation mode, maintaining a stable organic matter removal.
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Affiliation(s)
- Nathalie Dyane Miranda Slompo
- Department of Hydraulics and Sanitation, University of São Paulo (EESC-USP), 400 Trabalhador São Carlense Avenue, São Carlos, São Paulo 13566-590, Brazil E-mail:
| | - Larissa Quartaroli
- Department of Environmental and Civil Engineering, University of São Paulo State (FEB-UNESP), 14-01 'Engenheiro Luiz Edmundo Carrijo Coube' Avenue, Bauru, São Paulo 17033-360, Brazil
| | | | - Gustavo Henrique Ribeiro da Silva
- Department of Environmental and Civil Engineering, University of São Paulo State (FEB-UNESP), 14-01 'Engenheiro Luiz Edmundo Carrijo Coube' Avenue, Bauru, São Paulo 17033-360, Brazil
| | - Luiz Antonio Daniel
- Department of Hydraulics and Sanitation, University of São Paulo (EESC-USP), 400 Trabalhador São Carlense Avenue, São Carlos, São Paulo 13566-590, Brazil E-mail:
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Santos PRD, Daniel LA. Dissolved air flotation as a potential treatment process to remove Giardia cysts from anaerobically treated sewage. ENVIRONMENTAL TECHNOLOGY 2017; 38:2392-2399. [PMID: 27852162 DOI: 10.1080/09593330.2016.1262461] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 11/15/2016] [Indexed: 06/06/2023]
Abstract
Controlling Giardia cysts in sewage is an essential barrier for public health protection, reducing possible routes of protozoa transmission. The aim of this study was to evaluate the capability of dissolved air flotation (DAF), on a bench scale, to remove Giardia cysts from anaerobic effluent. Moreover, removals of indicator microorganisms and physical variables were also investigated. Flocculation conditions were studied, associating different flocculation times with different mean velocity gradients. DAF treatment achieved mean log removals in the range of 2.52-2.62 for Giardia cysts, depending on the flocculation condition. No statistical differences were observed among the flocculation conditions in terms of cyst removal. Low levels of turbidity and apparent color obtained from the treated effluent may indicate good treatment conditions for the DAF process in cyst removal. Indicator microorganisms were not able to predict the parasitological quality of the wastewater treated by flotation in terms of cyst concentrations. The DAF process provided an effective barrier to control cysts from sewage, which is an important parasite source.
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Affiliation(s)
- Priscila Ribeiro Dos Santos
- a Hydraulics and Sanitation Department , Engineering School of São Carlos, University of São Paulo , São Carlos - São Paulo , Brazil
| | - Luiz Antonio Daniel
- a Hydraulics and Sanitation Department , Engineering School of São Carlos, University of São Paulo , São Carlos - São Paulo , Brazil
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11
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Santos PRD, Daniel LA. Occurrence and removal of Giardia spp. cysts and Cryptosporidium spp. oocysts from a municipal wastewater treatment plant in Brazil. ENVIRONMENTAL TECHNOLOGY 2017; 38:1245-1254. [PMID: 27573723 DOI: 10.1080/09593330.2016.1223175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 08/07/2016] [Indexed: 06/06/2023]
Abstract
Sewage and sewage sludge have been recognized as potential sources of two important waterborne pathogenic protozoa: Giardia spp. and Cryptosporidium spp. Due to the lack of studies about the occurrence of these pathogens in sewage and sludge in Brazil, an investigation was conducted at various stages of a municipal wastewater treatment plant (WWTP) aiming to assess the occurrence of Giardia spp. cysts and Cryptosporidium spp. oocysts, their removal by the treatment processes, which are upflow anaerobic sludge blanket (UASB) reactor and dissolved air flotation process, and also the correlations between protozoa and indicator microorganisms. Significant quantities of cysts were detected in 100% of the analyzed wastewater samples, while oocysts were detected only in 39.0% of all wastewater samples. The overall removal of Giardia spp. cysts from the WWTP was on average 2.03 log, and the UASB reactor was more efficient than flotation. The sludge samples presented high quantities of (oo)cysts, implying the risks of contamination in the case of sludge reuse or inadequate disposal. Giardiasis prevalence was estimated between 2.21% and 6.7% for the population served by the WWTP, while cryptosporidiosis prevalence was much lower. Significant positive correlation was obtained only between cysts and Clostridium spores in anaerobic effluent.
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Affiliation(s)
- Priscila Ribeiro Dos Santos
- a Hydraulics and Sanitation Department, Engineering School of São Carlos , University of São Paulo , São Carlos - São Paulo , Brazil
| | - Luiz Antonio Daniel
- a Hydraulics and Sanitation Department, Engineering School of São Carlos , University of São Paulo , São Carlos - São Paulo , Brazil
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