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Wang S, Li Y, Xiao K, Huang X. Fluorescence excitation-emission matrix as a novel indicator of assimilable organic carbon in wastewater: Implication from a coal chemical wastewater study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 804:150144. [PMID: 34517310 DOI: 10.1016/j.scitotenv.2021.150144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/18/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
Assimilable organic carbon (AOC) is recognized as an important parameter to evaluate the biostability of water. Studies have been carried out to investigate the easier and faster AOC detection methods in recent years. In our study, the relationship between AOC and excitation-emission matrix (EEM) was investigated through analysis of wastewater from a coal chemical industrial corporation, including biochemical effluent, ultrafiltration effluent, and reverse osmosis concentrate. Considering the influence of water sample properties on AOC distribution, these water samples were fractionated according to their hydrophilicity and acid/base properties. Neutrals and hydrophobic acids were major components of total organic carbon and AOC concentration of these fractions was measured. EEM spectra of water samples were divided into five regions according to fluorescence peaks. Distribution of fluorescence region integration (FRI) of water samples was also calculated, as well as other fluorescence parameters. Statistical analysis showed that the concentration of AOC presented high positive correlation with the FRI in region H2, with R2 = 0.696. Monte Carlo simulation also proved that the proportion of significant R2 (p < 0.05) was high at 89.1%, suggesting that the model was reliable at least at the qualitative level. In that case, FRI in Region H2 could be an indication for AOC concentration in water samples. Our findings focus on fundamental insights into establishing relationship between spectroscopy method and AOC in wastewater and provide an easier way of accessing AOC in coal chemical industrial wastewater. Further investigation could be oriented to the dynamic analysis of AOC transformation and tracing.
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Affiliation(s)
- Shu Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; CAUPD Beijing Planning & Design Consultants Ltd, Beijing 100044, China
| | - Yufang Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Kang Xiao
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Xia Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Research and Application Center for Membrane Technology, School of Environment, Tsinghua University, Beijing 100084, China.
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2
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Ryu H, Addor Y, Brinkman NE, Ware MW, Boczek L, Hoelle J, Mistry JH, Keely SP, Villegas EN. Understanding Microbial Loads in Wastewater Treatment Works as Source Water for Water Reuse. WATER 2021; 13. [PMID: 34804602 PMCID: PMC8597597 DOI: 10.3390/w13111452] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Facing challenges in water demands and population size, particularly in the water-scarce regions in the United States, the reuse of treated municipal wastewater has become a viable potential to relieve the ever-increasing demands of providing water for (non-)potable use. The objectives of this study were to assess microbial quality of reclaimed water and to investigate treatability of microorganisms during different treatment processes. Raw and final treated effluent samples from three participating utilities were collected monthly for 16 months and analyzed for various microbial pathogens and fecal indicator organisms. Results revealed that the detectable levels of microbial pathogens tested were observed in the treated effluent samples from all participating utilities. Log10 reduction values (LRVs) of Cryptosporidium oocysts and Giardia cysts were at least two orders of magnitude lower than those of human adenovirus and all fecal indicator organisms except for aerobic endospores, which showed the lowest LRVs. The relatively higher LRV of the indicator organisms such as bacteriophages suggested that these microorganisms are not good candidates of viral indicators of human adenovirus during wastewater treatment processes. Overall, this study will assist municipalities considering the use of wastewater effluent as another source of drinking water by providing important data on the prevalence, occurrence, and reduction of waterborne pathogens in wastewater. More importantly, the results from this study will aid in building a richer microbial occurrence database that can be used towards evaluating reuse guidelines and disinfection practices for water reuse practices.
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Affiliation(s)
- Hodon Ryu
- Center for Environmental Solutions and Emergency Response, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Yao Addor
- Center for Environmental Measurement and Modeling, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Nichole E. Brinkman
- Center for Environmental Solutions and Emergency Response, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Michael W. Ware
- Center for Environmental Measurement and Modeling, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Laura Boczek
- Center for Environmental Solutions and Emergency Response, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Jill Hoelle
- Center for Environmental Solutions and Emergency Response, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Jatin H. Mistry
- United States Environmental Protection Agency, Region 6, Dallas, TX 75270, USA
| | - Scott P. Keely
- Center for Environmental Measurement and Modeling, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Eric N. Villegas
- Center for Environmental Measurement and Modeling, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, USA
- Correspondence:
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3
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Ren X, Chen H. Effect of residual chlorine on the interaction between bacterial growth and assimilable organic carbon and biodegradable organic carbon in reclaimed water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 752:141223. [PMID: 32898796 DOI: 10.1016/j.scitotenv.2020.141223] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 05/15/2023]
Abstract
Reclaimed water can significantly reduce household water consumption. However, microbial growth introduces several problems to reclaimed water, including health concerns, aesthetic deterioration and biofouling. Biological stability refers to the potential of organic matter or nutrients in water to support heterotrophic bacterial growth (HPC). Assimilable organic carbon (AOC) and biodegradable organic carbon (BDOC) are often used as indicators to evaluate the biological stability of water. This study investigated the effect of residual chlorine on the interaction between bacterial regrowth and AOC or BDOC and the variation of AOC after chlorine disinfection in reclaimed water. The results show that the HPC level is insensitive to AOC concentration when residual chlorine is >0.5 mg/L; however, the effects are more pronounced when residual chlorine is <0.5 mg/L. A residual chlorine concentration of >0.5 mg/L therefore maintains biological stability in reclaimed water. When residual chlorine was <0.5 mg/L, HPC levels were found to be limited when AOC was <128 μg/L or BDOC was <0.25 mg/L; and when residual chlorine was >0.5 mg/L, HPC levels were found to be limited when AOC was <796 μg/L or BDOC was <0.85 mg/L in reclaimed water. After chlorine disinfection, AOC contents initially increase and then decrease gradually, reaching minimum levels around day 20, and then increase in both greywater reclaimed water and mixed wastewater reclaimed water. Maintaining the chlorine demand and controlling the AOC level is critical for producing an effect on microbial regrowth and stabilising reclaimed water. The results of this study are conducive to the popularisation of reclaimed water use and also provide reference for reuse standards of reclaimed water.
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Affiliation(s)
- Xueli Ren
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Hongbin Chen
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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4
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Deng S, Yan X, Zhu Q, Liao C. The utilization of reclaimed water: Possible risks arising from waterborne contaminants. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 254:113020. [PMID: 31421574 DOI: 10.1016/j.envpol.2019.113020] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 07/11/2019] [Accepted: 08/04/2019] [Indexed: 05/04/2023]
Abstract
Increasing interest of seeking substitutable water resources accrues from shortage of freshwater. One of the options considered is reclaimed water (also designated as recycled water) that has been widely used in daily life. Although reclaimed water can serve as a feasible reliever of water pressure, attention about its technologies and potential risks is growing in the meantime. Most established wastewater treatment plants (WWTPs) predate many new contaminants, which means treatment processes cannot ensure to dislodge certain contaminants completely from origin water. Furthermore, a wide range of factors, such as seasons and influent variations, affect occurrence and concentration of reclaimed water-borne contaminants, making research about quality of reclaimed water especially significant. Many reclaimed water-borne contaminants, including biological and chemical contaminants, are toxic to human health, and complex wastewater matrix may aggravate water quality of concern. The widespread use of reclaimed water continues to be a concern on agriculture, ecological environment and human health. This study aims to: 1) provide a critical review about occurrence and profiles of diverse contaminants in the treated reclaimed water, 2) discuss the possibility to avoid the secondary pollution in reuse of reclaimed water, and 3) reveal the prospective consequences of using reclaimed water on agriculture, ecological environment and human health.
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Affiliation(s)
- Shenxi Deng
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xueting Yan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingqing Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunyang Liao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Environment and Health, Jianghan University, Wuhan, Hubei 430056, China.
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5
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Song P, Zhou B, Feng G, Brooks JP, Zhou H, Zhao Z, Liu Y, Li Y. The influence of chlorination timing and concentration on microbial communities in labyrinth channels: implications for biofilm removal. BIOFOULING 2019; 35:401-415. [PMID: 31142151 DOI: 10.1080/08927014.2019.1600191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/18/2019] [Accepted: 03/22/2019] [Indexed: 06/09/2023]
Abstract
Chlorination is an effective method to control biofilm formation in enclosed pipelines. To date, very little is known about how to control biofilms at the mesoscale in complex pipelines through chlorination. In this study, the dynamic of microbial communities was examined under different residual chlorine concentrations on the biofilms attached to labyrinth channels for drip irrigation using reclaimed water. The results indicated that the microbial phospholipid fatty acids, extracellular polymeric substances, microbial dynamics, and the ace and Shannon microbial diversity indices showed a gradual decrease after chlorination. However, chlorination increased microbial activity by 0.5-19.2%. The increase in the relative abundances of chloride-resistant bacteria (Acinetobacter and Thermomonas) could lead to a potential risk of chlorine resistance. Thus, keeping a low chlorine concentration (0.83 mg l-1 for 3 h) is effective for controlling biofilm formation in the labyrinth channels.
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Affiliation(s)
- Peng Song
- a College of Water Resources and Civil Engineering , China Agricultural University , Beijing , PR China
- b Genetics and Sustainable Agricultural Research Unit , United States Department of Agriculture , Starkville , MS , USA
| | - Bo Zhou
- a College of Water Resources and Civil Engineering , China Agricultural University , Beijing , PR China
- c College of Agricultural and Life Sciences , University of Wisconsin-Madison , Madison , WI , USA
| | - Gary Feng
- b Genetics and Sustainable Agricultural Research Unit , United States Department of Agriculture , Starkville , MS , USA
| | - John P Brooks
- b Genetics and Sustainable Agricultural Research Unit , United States Department of Agriculture , Starkville , MS , USA
| | - Hongxu Zhou
- a College of Water Resources and Civil Engineering , China Agricultural University , Beijing , PR China
| | - Zhirui Zhao
- d Research Center for Eco-environmental Sciences , Chinese Academy of Sciences , Beijing , PR China
| | - Yaoze Liu
- e Department of Environmental and Sustainable Engineering , University at Albany , Albany , NY , USA
| | - Yunkai Li
- a College of Water Resources and Civil Engineering , China Agricultural University , Beijing , PR China
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6
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Zhu L, Torres M, Betancourt WQ, Sharma M, Micallef SA, Gerba C, Sapkota AR, Sapkota A, Parveen S, Hashem F, May E, Kniel K, Pop M, Ravishankar S. Incidence of fecal indicator and pathogenic bacteria in reclaimed and return flow waters in Arizona, USA. ENVIRONMENTAL RESEARCH 2019; 170:122-127. [PMID: 30579985 DOI: 10.1016/j.envres.2018.11.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/13/2018] [Accepted: 11/30/2018] [Indexed: 06/09/2023]
Abstract
The quality of irrigation water used to cultivate produce that is consumed raw is an important issue with regard to food safety. In this study, the microbiological quality of potential irrigation water sources in Arizona was evaluated by testing for the presence of indicator and pathogenic bacteria. Reclaimed water samples were collected from two wastewater treatment plants and return flow samples were collected from two drainage canals and one return flow pond. Standard membrane filtration methods were used for detection of indicator bacteria. Water samples (n = 28) were filtered through cellulose ester membrane filters and bacterial populations were enumerated by placing the filters on selective agar. For detection of pathogens (Salmonella enterica, Listeria monocytogenes and Shiga toxin-producing E. coli (STEC)), water samples were filtered through Modified Moore swabs and enriched in Universal Pre-enrichment Broth, followed by selective enrichment broth for each pathogen. The enriched broth was streaked onto agar media selective for each pathogen. Presumptive colonies were confirmed by PCR/real-time PCR. Among the 14 reclaimed water samples from two sites, the ranges of recovered populations of E. coli, total coliforms, and enterococci were 0-1.3, 0.5-8.3 × 103, and 0-5.5 CFU/100 mL, respectively. No L. monocytogenes, Salmonella or STEC were found. In the 13 return flow water samples from 3 sites, the ranges of recovered populations of E. coli, total coliforms and enterococci were 1.9-5.3 × 102, 6.5 × 102-9.1 × 104, and 2.9-3.7× 103 CFU/100 mL, respectively. All samples were negative for L. monocytogenes. One (7.1%) of the return flow samples was positive for E. coli O145. Nine (64.3%) of the samples were positive for Salmonella. Both real-time PCR and culture-based methods were used for the detection of Salmonella and L. monocytogenes, and the results from the two methods were comparable. The findings of this study provide evidence that irrigation waters in Arizona, including reclaimed water and return flows, could be potential sources of bacterial contamination of produce. Additional work is needed to evaluate whether bacteria present in irrigation water sources transfer to the edible portion of irrigated plants and are capable of persisting through post-harvest activities.
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Affiliation(s)
- Libin Zhu
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, United States
| | - Monique Torres
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, United States
| | - Walter Q Betancourt
- Department of Soil, Water, and Environmental Science, University of Arizona, 2959 W Calle Agua Nueva, Tucson, AZ 85745, United States
| | - Manan Sharma
- Environmental Microbial & Food Safety Lab, USDA-ARS, 10300 Baltimore Avenue, Beltsville, MD 20705, United States
| | - Shirley A Micallef
- Department of Plant Science and Landscape Architecture, University of Maryland, 2126 Plant Sciences Building, College Park, MD 20742, United States; Centre for Food Safety and Security Systems, University of Maryland, College Park, MD 20742, United States
| | - Charles Gerba
- Department of Soil, Water, and Environmental Science, University of Arizona, 2959 W Calle Agua Nueva, Tucson, AZ 85745, United States
| | - Amy R Sapkota
- School of Public Health, University of Maryland, 2234P SPH Building, College Park, MD 20742, United States
| | - Amir Sapkota
- School of Public Health, University of Maryland, 2234P SPH Building, College Park, MD 20742, United States
| | - Salina Parveen
- Department of Agriculture, Food, and Resource Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, United States
| | - Fawzy Hashem
- Department of Agriculture, Food, and Resource Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, United States
| | - Eric May
- Department of Agriculture, Food, and Resource Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, United States
| | - Kalmia Kniel
- Department of Animal and Food Sciences, University of Delaware, 044 Townsend Hall, Newark, DE 19716, United States
| | - Mihai Pop
- Department of Computer Science & the Center for Bioinformatics and Computational Biology, University of Maryland, 8223 Paint Branch Drive, College Park, MD 20742, United States
| | - Sadhana Ravishankar
- School of Animal and Comparative Biomedical Sciences, University of Arizona, 1117 E. Lowell Street, Tucson, AZ 85721, United States.
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7
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Garner E, Chen C, Xia K, Bowers J, Engelthaler DM, McLain J, Edwards MA, Pruden A. Metagenomic Characterization of Antibiotic Resistance Genes in Full-Scale Reclaimed Water Distribution Systems and Corresponding Potable Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:6113-6125. [PMID: 29741366 DOI: 10.1021/acs.est.7b05419] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Water reclamation provides a valuable resource for meeting nonpotable water demands. However, little is known about the potential for wastewater reuse to disseminate antibiotic resistance genes (ARGs). Here, samples were collected seasonally in 2014-2015 from four U.S. utilities' reclaimed and potable water distribution systems before treatment, after treatment, and at five points of use (POU). Shotgun metagenomic sequencing was used to profile the resistome (i.e., full contingent of ARGs) of a subset ( n = 38) of samples. Four ARGs ( qnrA, blaTEM, vanA, sul1) were quantified by quantitative polymerase chain reaction. Bacterial community composition (via 16S rRNA gene amplicon sequencing), horizontal gene transfer (via quantification of intI1 integrase and plasmid genes), and selection pressure (via detection of metals and antibiotics) were investigated as potential factors governing the presence of ARGs. Certain ARGs were elevated in all ( sul1; p ≤ 0.0011) or some ( blaTEM, qnrA; p ≤ 0.0145) reclaimed POU samples compared to corresponding potable samples. Bacterial community composition was weakly correlated with ARGs (Adonis, R2 = 0.1424-0.1734) and associations were noted between 193 ARGs and plasmid-associated genes. This study establishes that reclaimed water could convey greater abundances of certain ARGs than potable waters and provides observations regarding factors that likely control ARG occurrence in reclaimed water systems.
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Affiliation(s)
- Emily Garner
- Via Department of Civil and Environmental Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Chaoqi Chen
- Department of Crop and Soil Environmental Sciences , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Kang Xia
- Department of Crop and Soil Environmental Sciences , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Jolene Bowers
- Translational Genomics Research Institute , Flagstaff , Arizona 86005 , United States
| | - David M Engelthaler
- Translational Genomics Research Institute , Flagstaff , Arizona 86005 , United States
| | - Jean McLain
- Water Resources Research Center , University of Arizona , Tucson , Arizona 85719 , United States
| | - Marc A Edwards
- Via Department of Civil and Environmental Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Amy Pruden
- Via Department of Civil and Environmental Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
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8
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Chen Z, Yu T, Ngo HH, Lu Y, Li G, Wu Q, Li K, Bai Y, Liu S, Hu HY. Assimilable organic carbon (AOC) variation in reclaimed water: Insight on biological stability evaluation and control for sustainable water reuse. BIORESOURCE TECHNOLOGY 2018; 254:290-299. [PMID: 29398290 DOI: 10.1016/j.biortech.2018.01.111] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 01/20/2018] [Accepted: 01/22/2018] [Indexed: 05/05/2023]
Abstract
This review highlights the importance of conducting biological stability evaluation due to water reuse progression. Specifically, assimilable organic carbon (AOC) has been identified as a practical indicator for microbial occurrence and regrowth which ultimately influence biological stability. Newly modified AOC bioassays aimed for reclaimed water are introduced. Since elevated AOC levels are often detected after tertiary treatment, the review emphasizes that actions can be taken to either limit AOC levels prior to disinfection or conduct post-treatment (e.g. biological filtration) as a supplement to chemical oxidation based approaches (e.g. ozonation and chlorine disinfection). During subsequent distribution and storage, microbial community and possible microbial regrowth caused by complex interactions are discussed. It is suggested that microbial surveillance, AOC threshold values, real-time field applications and surrogate parameters could provide additional information. This review can be used to formulate regulatory plans and strategies, and to aid in deriving relevant control, management and operational guidance.
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Affiliation(s)
- Zhuo Chen
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China
| | - Tong Yu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Huu Hao Ngo
- School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Yun Lu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Guoqiang Li
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Qianyuan Wu
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China
| | - Kuixiao Li
- Research and Development Center, Beijing Drainage Group Co., Ltd, Beijing 100124, PR China
| | - Yu Bai
- Research and Development Center, Beijing Drainage Group Co., Ltd, Beijing 100124, PR China
| | - Shuming Liu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China.
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9
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Carey SA, Goldstein RER, Gibbs SG, Claye E, He X, Sapkota AR. Occurrence of vancomycin-resistant and -susceptible Enterococcus spp. in reclaimed water used for spray irrigation. ENVIRONMENTAL RESEARCH 2016; 147:350-5. [PMID: 26942838 PMCID: PMC8223762 DOI: 10.1016/j.envres.2016.02.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 02/04/2016] [Accepted: 02/18/2016] [Indexed: 05/20/2023]
Abstract
Reclaiming municipal wastewater for agricultural, environmental, and industrial purposes is increasing in the United States to combat dwindling freshwater supplies. However, there is a lack of data regarding the microbial quality of reclaimed water. In particular, no previous studies have evaluated the occurrence of vancomycin-resistant enterococci (VRE) in reclaimed water used at spray irrigation sites in the United States. To address this knowledge gap, we investigated the occurrence, concentration, and antimicrobial resistance patterns of VRE and vancomycin-susceptible enterococci at three U.S. spray irrigation sites that use reclaimed water. We collected 48 reclaimed water samples from one Mid-Atlantic and two Midwest spray irrigation sites, as well as their respective wastewater treatment plants, in 2009 and 2010. Samples were analyzed for total enterococci and VRE using standard membrane filtration. Isolates were purified and then confirmed using biochemical tests and PCR. Antimicrobial susceptibility testing was conducted using the Sensititre® microbroth dilution system. Data were analyzed by two-sample proportion tests and one-way analysis of variance. We detected total enterococci and VRE in 71% (34/48) and 4% (2/48) of reclaimed water samples, respectively. Enterococcus faecalis was the most common species identified. At the Mid-Atlantic spray irrigation site, UV radiation decreased total enterococci to undetectable levels; however, subsequent storage in an open-air pond at this site resulted in increased concentrations of enterococci. E. faecalis isolates recovered from the Mid-Atlantic spray irrigation site expressed intrinsic resistance to quinupristin/dalfopristin; however, non-E. faecalis isolates expressed resistance to quinupristin/dalfopristin (52% of isolates), vancomycin (4%), tetracycline (13%), penicillin (4%) and ciprofloxacin (17%). Our findings show that VRE are present in low numbers in reclaimed water at point-of-use at the sampled spray irrigation sites; however, resistance to other antimicrobial classes is more prevalent, particularly among non-E. faecalis isolates.
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Affiliation(s)
- Stephanie Ann Carey
- Maryland Institute for Applied Environmental Health, University of Maryland School of Public Health, College Park, MD, USA
| | - Rachel E Rosenberg Goldstein
- Maryland Institute for Applied Environmental Health, University of Maryland School of Public Health, College Park, MD, USA
| | - Shawn G Gibbs
- Department of Environmental Health, School of Public Health-Bloomington, Indiana University, Bloomington, IN, USA
| | - Emma Claye
- Maryland Institute for Applied Environmental Health, University of Maryland School of Public Health, College Park, MD, USA
| | - Xin He
- Department of Epidemiology and Biostatistics, University of Maryland School of Public Health, College Park, MD, USA
| | - Amy R Sapkota
- Maryland Institute for Applied Environmental Health, University of Maryland School of Public Health, College Park, MD, USA.
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10
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Lin YW, Li D, Gu AZ, Zeng SY, He M. Bacterial regrowth in water reclamation and distribution systems revealed by viable bacterial detection assays. CHEMOSPHERE 2016; 144:2165-74. [PMID: 26595310 DOI: 10.1016/j.chemosphere.2015.10.071] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 05/21/2023]
Abstract
Microbial regrowth needs to be managed during water reclamation and distribution. The aim of present study was to investigate the removal and regrowth of Escherichia coli (E. coli) and Salmonella in water reclamation and distribution system by using membrane integrity assay (PMA-qPCR), reverse transcriptional activity assay (Q-RT-PCR) and culture-based assay, and also to evaluate the relationships among bacterial regrowth, and environmental factors in the distribution system. The results showed that most of the water reclamation processes potentially induced bacteria into VBNC state. The culturable E. coli and Salmonella regrew 1.8 and 0.7 log10 in distribution system, which included reactivation of bacteria in the viable but non-culturable (VBNC) state and reproduction of culturable bacteria. The regrowth of culturable E. coli and Salmonella in the distribution system mainly depended on the residual chlorine levels, with correlations (R(2)) of -0.598 and -0.660. The abundances of membrane integrity and reverse transcriptional activity bacteria in reclamation effluents had significant correlations with the culturable bacteria at the end point of the distribution system, demonstrating that PMA-qPCR and Q-RT-PCR are sensitive and accurate tools to determine and predict bacterial regrowth in water distribution systems. This study has improved our understanding of microbial removal and regrowth in reclaimed water treatment and distribution systems. And the results also recommended that more processes should be equipped to remove viable bacteria in water reclamation plants for the sake of inhibition microbial regrowth during water distribution and usages.
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Affiliation(s)
- Yi-wen Lin
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Dan Li
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
| | - April Z Gu
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA
| | - Si-yu Zeng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Miao He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
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11
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Botsaris G, Kanetis L, Slaný M, Parpouna C, Makris KC. Microbial quality and molecular identification of cultivable microorganisms isolated from an urban drinking water distribution system (Limassol, Cyprus). ENVIRONMENTAL MONITORING AND ASSESSMENT 2015; 187:739. [PMID: 26559553 DOI: 10.1007/s10661-015-4957-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 11/02/2015] [Indexed: 06/05/2023]
Abstract
Microorganisms can survive and multiply in aged urban drinking water distribution systems, leading to potential health risks. The objective of this work was to investigate the microbial quality of tap water and molecularly identify its predominant cultivable microorganisms. Tap water samples collected from 24 different households scattered in the urban area of Limassol, Cyprus, were microbiologically tested following standard protocols for coliforms, E. coli, Pseudomonas spp., Enterococcus spp., and total viable count at 22 and 37 °C. Molecular identification was performed on isolated predominant single colonies using 16SrRNA sequencing. Approximately 85% of the household water samples were contaminated with one or more microorganisms belonging to the genera of Pseudomonas, Corynebacterium, Agrobacterium, Staphylococcus, Bacillus, Delftia, Acinetobacter, Enterococcus, Enterobacter, and Aeromonas. However, all samples tested were free from E. coli. This is the first report in Cyprus molecularly confirming specific genera of relevant microbial communities in tap water.
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Affiliation(s)
- George Botsaris
- Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, 3603, Limassol, Cyprus.
| | - Loukas Kanetis
- Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, 3603, Limassol, Cyprus
| | - Michal Slaný
- Veterinary Research Institute, Hudcova 70, 621 00, Brno, Czech Republic
| | - Christiana Parpouna
- Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, 3603, Limassol, Cyprus
| | - Konstantinos C Makris
- Water and Health Laboratory, Cyprus International Institute for Environmental and Public Health in association with the Harvard School of Public Health, Cyprus University of Technology, Limassol, Cyprus
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12
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Zhao X, Huang H, Hu HY, Su C, Zhao J, Liu SM. Increase of microbial growth potential in municipal secondary effluent by coagulation. CHEMOSPHERE 2014; 109:14-19. [PMID: 24873701 DOI: 10.1016/j.chemosphere.2014.02.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 02/15/2014] [Accepted: 02/19/2014] [Indexed: 06/03/2023]
Abstract
Microbial growth is a big issue of concern in the use of reclaimed water. In this study, the variation of microbial growth potentials of municipal secondary effluents after coagulation was evaluated by measuring assimilable organic carbon (AOC). Surprisingly, the AOC levels increased significantly (55-667%) after coagulation with poly-aluminum dosages of 60 mgL(-1) for the samples investigated in this research. By ultrafiltration membrane fractionation, the microbial growth potentials of the fractions with different molecular weight (MW) were measured. The results revealed that the maximum cell densities of microbial growth in secondary effluents were lower than those in their fractions with MW<10kDa. Meanwhile, the organic component with MW>10kDa in biological treated effluents was proved to have an inhibitory effect on microbial growth. Therefore, the removal of those high MW organic matters was the main reason for the increase of microbial growth potential in secondary effluents during coagulation. Furthermore, polysaccharides and/or proteins in secondary effluents were easily removed by coagulation and were thought to be the possible key organic substances affecting the microbial growth potential during coagulation. It is suggested that post treatments would be needed after coagulation to maintain the biological stability of reclaimed water.
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Affiliation(s)
- Xin Zhao
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China
| | - Huang Huang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China; School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
| | - Chang Su
- College of Environment and Resources, Inner Mongolia University, Huhhot 010021, China
| | - Ji Zhao
- College of Environment and Resources, Inner Mongolia University, Huhhot 010021, China
| | - Shu-Ming Liu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China
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13
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Chaplin BP. Critical review of electrochemical advanced oxidation processes for water treatment applications. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:1182-203. [PMID: 24549240 DOI: 10.1039/c3em00679d] [Citation(s) in RCA: 243] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Electrochemical advanced oxidation processes (EAOPs) have emerged as novel water treatment technologies for the elimination of a broad-range of organic contaminants. Considerable validation of this technology has been performed at both the bench-scale and pilot-scale, which has been facilitated by the development of stable electrode materials that efficiently generate high yields of hydroxyl radicals (OH˙) (e.g., boron-doped diamond (BDD), doped-SnO2, PbO2, and substoichiometic- and doped-TiO2). Although a promising new technology, the mechanisms involved in the oxidation of organic compounds during EAOPs and the corresponding environmental impacts of their use have not been fully addressed. In order to unify the state of knowledge, identify research gaps, and stimulate new research in these areas, this review critically analyses published research pertaining to EAOPs. Specific topics covered in this review include (1) EAOP electrode types, (2) oxidation pathways of select classes of contaminants, (3) rate limitations in applied settings, and (4) long-term sustainability. Key challenges facing EAOP technologies are related to toxic byproduct formation (e.g., ClO4(-) and halogenated organic compounds) and low electro-active surface areas. These challenges must be addressed in future research in order for EAOPs to realize their full potential for water treatment.
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Affiliation(s)
- Brian P Chaplin
- Department of Chemical Engineering, University of Illinois at Chicago, 810 S. Clinton Ave., Chicago, IL 60607, USA.
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14
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Fahrenfeld N, Ma Y, O'Brien M, Pruden A. Reclaimed water as a reservoir of antibiotic resistance genes: distribution system and irrigation implications. Front Microbiol 2013; 4:130. [PMID: 23755046 PMCID: PMC3664959 DOI: 10.3389/fmicb.2013.00130] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/06/2013] [Indexed: 12/21/2022] Open
Abstract
Treated wastewater is increasingly being reused to achieve sustainable water management in arid regions. The objective of this study was to quantify the distribution of antibiotic resistance genes (ARGs) in recycled water, particularly after it has passed through the distribution system, and to consider point-of-use implications for soil irrigation. Three separate reclaimed wastewater distribution systems in the western U.S. were examined. Quantitative polymerase chain reaction (qPCR) was used to quantify ARGs corresponding to resistance to sulfonamides (sul1, sul2), macrolides (ermF), tetracycline [tet(A), tet(O)], glycopeptides (vanA), and methicillin (mecA), in addition to genes present in waterborne pathogens Legionella pneumophila (Lmip), Escherichia coli (gadAB), and Pseudomonas aeruginosa (ecfx, gyrB). In a parallel lab study, the effect of irrigating an agricultural soil with secondary, chlorinated, or dechlorinated wastewater effluent was examined in batch microcosms. A broader range of ARGs were detected after the reclaimed water passed through the distribution systems, highlighting the importance of considering bacterial re-growth and the overall water quality at the point of use (POU). Screening for pathogens with qPCR indicated presence of Lmip and gadAB genes, but not ecfx or gyrB. In the lab study, chlorination was observed to reduce 16S rRNA and sul2 gene copies in the wastewater effluent, while dechlorination had no apparent effect. ARGs levels did not change with time in soil slurries incubated after a single irrigation event with any of the effluents. However, when irrigated repeatedly with secondary wastewater effluent (not chlorinated or dechlorinated), elevated levels of sul1 and sul2 were observed. This study suggests that reclaimed water may be an important reservoir of ARGs, especially at the POU, and that attention should be directed toward the fate of ARGs in irrigation water and the implications for human health.
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Affiliation(s)
- Nicole Fahrenfeld
- Department of Civil and Environmental Engineering, Virginia Tech Blacksburg, VA, USA
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15
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Casanovas-Massana A, Blanch AR. Determination of fecal contamination origin in reclaimed water open-air ponds using biochemical fingerprinting of enterococci and fecal coliforms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:3003-3010. [PMID: 23054766 DOI: 10.1007/s11356-012-1197-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 09/12/2012] [Indexed: 06/01/2023]
Abstract
Low levels of fecal indicator bacteria (FIB) were recently detected in two reclaimed water open-air ponds used to irrigate a golf course located in Northeastern Spain. The aim of this study was to evaluate the feasibility of a biochemical fingerprinting method to track the origin of fecal contamination in water with low FIB levels, as in the aforementioned ponds. We also aimed to determine whether FIB presence was due to regrowth of the reclaimed water populations or to a contribution of fecal matter whose source was in the golf facility. Three hundred and fifty enterococcal strains and 308 fecal coliform strains were isolated from the ponds and reclamation plant, and they were biochemically phenotyped. In addition, the inactivation of several microbial fecal pollution indicators (fecal coliforms, total bifidobacteria, sorbitol-fermenting bifidobacteria, somatic bacteriophages, and bacteriophages infecting Bacteroides thetaiotaomicron) was studied using a mesocosm in situ in order to obtain information about their decay rate. Although FIB concentration was low, the biochemical fingerprinting provided evidence that the origin of the fecal contamination in the ponds was not related to the reclaimed water. Biochemical fingerprinting thus proved to be a successful approach, since other microbial source-tracking methods perform poorly when dealing with low fecal load matrices. Furthermore, the mesocosm assays indicated that none of the microbial fecal indicators was able to regrow in the ponds. Finally, the study highlights the fact that reclaimed water may be recontaminated in open-air reservoirs, and therefore, its microbial quality should be monitored throughout its use.
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Affiliation(s)
- Arnau Casanovas-Massana
- Departament of Microbiology, University of Barcelona, Av. Diagonal, 643, 08028, Barcelona, Catalonia, Spain.
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Thayanukul P, Kurisu F, Kasuga I, Furumai H. Evaluation of microbial regrowth potential by assimilable organic carbon in various reclaimed water and distribution systems. WATER RESEARCH 2013; 47:225-32. [PMID: 23134741 DOI: 10.1016/j.watres.2012.09.051] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2012] [Revised: 09/26/2012] [Accepted: 09/28/2012] [Indexed: 05/21/2023]
Abstract
Microbial regrowth introduces several problems to the use of reclaimed water, such as health concerns, aesthetic deterioration, and biofouling. This study evaluated assimilable organic carbon (AOC), which is a part of the biodegradable organic matter promoting microbial growth, in water reclamation systems in Japan. The AOC concentration in the reclaimed water from various treatment processes ranged between 36 and 446 μg C/L (median 316 μg C/L). The AOC concentration in the reclaimed water from the plants equipped with ozonation was significantly higher - more than two times - than that in the reclaimed water from plants equipped with other processes. UV and chlorine also changed the AOC concentration slightly. Moreover, reverse osmosis produced reclaimed water with the lowest AOC content. Processes equipped with membrane filtration were effective in removing seed microorganisms that enter the distribution system. Microbial growth in reclaimed water distribution systems occurred when the total and free residual chlorine was lower than 0.36 and 0.09 mg/L, respectively. The AOC reduction occurred simultaneously with regrowth, which suggests that AOC could support microbial growth in reclaimed-water-distribution systems. As the residual chlorine is often depleted during distribution and storage, it is essential to control the AOC to suppress microbial growth.
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Affiliation(s)
- Parinda Thayanukul
- Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
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Abdul RM, Mutnuri L, Dattatreya PJ, Mohan DA. Assessment of drinking water quality using ICP-MS and microbiological methods in the Bholakpur area, Hyderabad, India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2012; 184:1581-1592. [PMID: 21544503 DOI: 10.1007/s10661-011-2062-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 04/11/2011] [Indexed: 05/30/2023]
Abstract
A total of 16 people died and over 500 people were hospitalized due to diarrhoeal illness in the Bholakpur area of Hyderabad, India on 6th May 2009. A study was conducted with immediate effect to evaluate the quality of municipal tap water of the Bholakpur locality. The study consists of the determination of physico-chemical properties, trace metals, heavy metals, rare earth elements and microbiological quality of drinking water. The data showed the variation of the investigated parameters in samples as follows: pH 7.14 to 8.72, EC 455 to 769 μS/cm, TDS 303.51 to 515.23 ppm and DO 1.01 to 6.83 mg/L which are within WHO guidelines for drinking water quality. The water samples were analyzed for 27 elements (Li, Be, B, Na, Mg, Al, Si, K, Ca, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Ba and Pb) using inductively coupled plasma-mass spectrometry (ICP-MS). The concentrations of Fe (0.12 to 1.13 mg/L), Pb (0.01 to 0.07 mg/L), Cu (0.01 to 0.19 mg/L), Ni (0.01 to 0.15 mg/L), Al (0.16 to 0.49 mg/L), and Na (38.36 to 68.69 mg/L) were obtained, which exceed the permissible limits of the World Health Organization (WHO) for drinking water quality guidelines. The remaining elements were within the permissible limits. The microbiological quality of water was tested using standard plate count, membrane filtration technique, thermotolerant coliform (TTC), and most probable number (MPN) methods. The total heterotrophic bacteria ranged from 1.0 × 10(5) to 18 × 10(7 )cfu/ml. Total viable bacteria in all the water samples were found to be too numerable to count and total number of coliform bacteria in all water samples were found to be of order of 1,100 to >2,400 MPN index/100 ml. TTC tested positive for coliform bacteria at 44.2°C. All the water samples of the study area exceeded the permissible counts of WHO and that (zero and minimal counts) of the control site (National Geophysical Research Institute) water samples. Excessively high colony numbers indicate that the water is highly contaminated with microorganisms and is hazardous for drinking purposes. Bacteriological pollution of drinking water supplies caused diarrhoeal illness in Bholakpur, which is due to the infiltration of contaminated water (sewage) through cross connection, leakage points, and back siphoning.
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Affiliation(s)
- Rasheed M Abdul
- Microbiology Laboratory, National Geophysical Research Institute, Council for Scientific and Industrial Research, Room no. 180, Second floor, Geochemistry Building, Hyderabad, Andhra Pradesh, India.
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18
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Regrowth of potential opportunistic pathogens and algae in reclaimed-water distribution systems. Appl Environ Microbiol 2010; 76:4169-78. [PMID: 20453149 DOI: 10.1128/aem.03147-09] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A study of the quality of reclaimed water in treated effluent, after storage, and at three points in the distribution system of four plants in California, Florida, Massachusetts, and New York was conducted for 1 year. The plants had different treatment processes (conventional versus membrane bioreactor), production capacities, and methods for storage of the water, and the intended end uses of the water were different. The analysis focused on the occurrence of indicator bacteria (heterotrophic bacteria, coliforms, Escherichia coli, and enterococci) and opportunistic pathogens (Aeromonas spp., enteropathogenic E. coli O157:H7, Legionella spp., Mycobacterium spp., and Pseudomonas spp.), as well as algae. Using immunological methods, E. coli O157:H7 was detected in the effluent of only one system, but it was not detected at the sampling points, suggesting that its survival in the system was poor. Although all of the treatment systems effectively reduced the levels of bacteria in the effluent, bacteria regrew in the reservoir and distribution systems because of the loss of residual disinfectant and high assimilable organic carbon levels. In the systems with open reservoirs, algal growth reduced the water quality by increasing the turbidity and accumulating at the end of the distribution system. Opportunistic pathogens, notably Aeromonas, Legionella, Mycobacterium, and Pseudomonas, occurred more frequently than indicator bacteria (enterococci, coliforms, and E. coli). The Mycobacterium spp. were very diverse and occurred most frequently in membrane bioreactor systems, and Mycobacterium cookii was identified more often than the other species. The public health risk associated with these opportunistic pathogens in reclaimed water is unknown. Collectively, our results show the need to develop best management practices for reclaimed water to control bacterial regrowth and degradation of water before it is utilized at the point of use.
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Wait IW. Multiple-barrier disinfection by chlorination and UV irradiation for desalinated drinking waters: chlorine photolysis and accelerated lamp-sleeve fouling effects. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2008; 80:2183-2188. [PMID: 19024734 DOI: 10.2175/106143008x304668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Experiments were conducted to quantify interaction effects between UV irradiation and chlorination for desalinated drinking water. The rate of chlorine photolysis in desalinated water was characterized using a low-pressure UV lamp and chlorine doses typical of drinking water treatment and was found to be lower than reported photolysis rates for treated surface water. Results indicate that, for most desalinated water applications, reduction in free chlorine is likely to be limited, but, depending on the UV dose used, not necessarily negligible. Investigation of the potential for reactor lamp-sleeve fouling included mineral speciation and solubility modeling and showed that chlorination of desalinated water before UV disinfection may increase lamp-sleeve fouling, particularly for point-of-use reactors. UV irradiation before chlorination may minimize fouling. Overall results point to the variable nature of UV lamp-sleeve fouling and chlorine photolysis and an intrinsic dependence on local water chemistry conditions.
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Affiliation(s)
- Isaac W Wait
- American University of Sharjah, P.O. Box 26666, Sharjah, United Arab Emirates.
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20
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Ryu H, Gerrity D, Crittenden JC, Abbaszadegan M. Photocatalytic inactivation of Cryptosporidium parvum with TiO(2) and low-pressure ultraviolet irradiation. WATER RESEARCH 2008; 42:1523-1530. [PMID: 18037465 DOI: 10.1016/j.watres.2007.10.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 10/16/2007] [Accepted: 10/23/2007] [Indexed: 05/25/2023]
Abstract
This study investigated the efficacy of low-pressure ultraviolet (UV) irradiation and the synergistic effect of UV/titanium dioxide (TiO(2)) photocatalysis on Cryptosporidium parvum oocyst inactivation. At UV doses of 2.7, 8.0, and 40mJ/cm(2), oocyst inactivation was 1.3, 2.6, and 3.3log(10), respectively. Reactive oxygen species (ROS) generated by longwave UV radiation (>315nm) and TiO(2) achieved less than 0.28-log inactivation. However, the synergistic effect of germicidal (254nm) UV and TiO(2) resulted in 2-log and 3-log oocyst inactivation with 4.0 and 11.0mJ/cm(2), respectively. Therefore, using TiO(2) in combination with UV reduced the dose requirement for 3-log inactivation by 56%. An approximate 1-log decrease in inactivation of oocysts was observed with nanopure water in comparison to buffered water, whereas changes in pH from 6 to 8 had little effect on the photocatalytic inactivation of oocysts in either matrix (P>0.1).
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Affiliation(s)
- Hodon Ryu
- Department of Civil and Environmental Engineering, National Science Foundation Water Quality Center, Arizona State University, ECG 252, Tempe, AZ 85287-5306, USA
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