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1.
Chemosphere ; 239: 124728, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31499314

RESUMEN

Numerous of pollutants threaten our planet, for instance plastic wastes causes a huge potential risk on the environment in addition to many of emergened pollutants as pharmaceutical residue in aquatic environments which affecting ecological balance and in-turn affecting human health. Accordingly, this research proposed an innovative facile, one-step synthesis of functionalized magnetic fullerene nanocomposite (FMFN) via catalytic thermal decomposition of sustainable poly (ethylene terephthalate) bottle wastes as feedstock and ferrocene as a catalyst and precursor of magnetite. Growth mechanism of FMFN was discussed and batch experiments were achieved to examine its adsorption efficiency in relation to Ciprofloxacin antibiotic. Different adsorption parameters including time, initial Ciprofloxacin concentration, and solution temperature were investigated and optimized using Response Surface Methodology (RSM) model. In addition, a study on the antibiotic adsorption process impact on the organisms of an ecosystem was conducted using E. coli DH5α, and results validated method's efficiency in overcoming problem of appearance of antibiotic-resistant microbes.


Asunto(s)
Ciprofloxacino/aislamiento & purificación , Fulerenos/química , Nanocompuestos/química , Contaminantes Químicos del Agua/aislamiento & purificación , Adsorción , Ciprofloxacino/química , Ecosistema , Escherichia coli , Concentración de Iones de Hidrógeno , Cinética , Fenómenos Magnéticos , Modelos Estadísticos , Plásticos , Tereftalatos Polietilenos/química , Tomografía de Emisión de Positrones , Reciclaje , Temperatura Ambiental , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Purificación del Agua/estadística & datos numéricos
2.
Isr Med Assoc J ; 21(9): 589-594, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31542902

RESUMEN

BACKGROUND: Cryptosporidium is a major threat to water supplies worldwide. Various biases and obstacles in case identification are recognized. In Israel, Cryptosporidiosis was included among notifiable diseases in 2001 in order to determine the burden of parasite-inflicted morbidity and to justify budgeting a central drinking water filtration plant. OBJECTIVES: To summarize the epidemiologic features of 14 years of Cryptosporidium surveillance and to assess the effects of advanced water purification treatment on the burden of disease. METHODS: From 2001 to 2014, a passive surveillance system was used. Cases were identified based on microscopic detection in stool samples. Confirmed cases were reported electronically to the Israeli Ministry of Health. Overall rates as well as age, gender, ethnicity and specific annual incidence were calculated per 100,000 population in five age groups: 0-4, 5-14, 15-44, 45-64, > 65 years. RESULTS: A total of 522 Cryptosporidium cases were reported in all six public health districts. More cases were detected among Jews and among males, and mainly in young children, with a seasonal peak during summer. The Haifa sub-district reported 69% of the cases. Most were linked to an outbreak from the summer of 2008, which was attributed to recreational swimming pool activity. Cases decreased after installation of a central filtration plant in 2007. CONCLUSIONS: As drinking water in Israel is treated to maximal international standards, the rationale for further inclusion of Cryptosporidium among mandatory notifiable diseases should be reconsidered. Future surveillance efforts should focus on timely detection of outbreaks using molecular high-throughput testing.


Asunto(s)
Criptosporidiosis/epidemiología , Cryptosporidium/aislamiento & purificación , Monitoreo Epidemiológico , Política de Salud , Adolescente , Adulto , Factores de Edad , Anciano , Niño , Preescolar , Costo de Enfermedad , Grupos Étnicos/estadística & datos numéricos , Femenino , Humanos , Incidencia , Lactante , Israel/epidemiología , Masculino , Persona de Mediana Edad , Vigilancia de la Población/métodos , Estaciones del Año , Factores Sexuales , Purificación del Agua/estadística & datos numéricos , Abastecimiento de Agua/estadística & datos numéricos , Adulto Joven
3.
BMC Public Health ; 19(1): 1188, 2019 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-31464621

RESUMEN

BACKGROUND: Water advisories, especially those concerning boiling drinking water, are widely used to reduce risks of infection from contaminants in the water supply. Since the effectiveness of boil water advisories (BWAs) depends on public compliance, monitoring the public response to such advisories is essential for protecting human health. However, assessments of public compliance with BWAs remain sparse. Thus, this study was aimed at investigating awareness and compliance among residents who had received BWAs in Baerum municipality in Norway. METHOD: We conducted a cross-sectional study among 2764 residents who had received water advisories by SMS in the municipality of Baerum between January and September 2017. We analysed data from two focus group discussions and an online survey sent to all residents who had received an advisory. We conducted descriptive analyses and calculated odds ratios (OR) using logistic regression to identify associations of compliance and awareness with demographic characteristics. RESULTS: Of the 611 respondents, 67% reported that they had received a water advisory notification. Effective compliance rate with safe drinking water practices, either by storing clean drinking water or boiling tap water, after a water outage was 72% among those who remembered receiving a notification. Compliance with safe drinking water advisories was lower among men than women (OR 0.53, 95% CI 0.29-0.96), but was independent of age, education and household type. The main reason for respondents' non-compliance with safe water practices was that they perceived the water to be safe to drink after letting it flush through the tap until it became clear. CONCLUSIONS: Awareness of advisories was suboptimal among residents who had received notifications, but compliance was high. The present study highlights the need to improve the distribution, phrasing and content of water advisory notifications to achieve greater awareness and compliance. Future studies should include hard-to-reach groups with adequate data collection approaches and examine the use of BWAs in a national context to inform future policies on BWAs.


Asunto(s)
Agua Potable/normas , Adhesión a Directriz/estadística & datos numéricos , Purificación del Agua/estadística & datos numéricos , Abastecimiento de Agua/estadística & datos numéricos , Adolescente , Adulto , Anciano , Concienciación , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Noruega , Embarazo , Encuestas y Cuestionarios , Purificación del Agua/métodos , Adulto Joven
4.
Nat Microbiol ; 4(7): 1183-1195, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31086312

RESUMEN

Microorganisms in wastewater treatment plants (WWTPs) are essential for water purification to protect public and environmental health. However, the diversity of microorganisms and the factors that control it are poorly understood. Using a systematic global-sampling effort, we analysed the 16S ribosomal RNA gene sequences from ~1,200 activated sludge samples taken from 269 WWTPs in 23 countries on 6 continents. Our analyses revealed that the global activated sludge bacterial communities contain ~1 billion bacterial phylotypes with a Poisson lognormal diversity distribution. Despite this high diversity, activated sludge has a small, global core bacterial community (n = 28 operational taxonomic units) that is strongly linked to activated sludge performance. Meta-analyses with global datasets associate the activated sludge microbiomes most closely to freshwater populations. In contrast to macroorganism diversity, activated sludge bacterial communities show no latitudinal gradient. Furthermore, their spatial turnover is scale-dependent and appears to be largely driven by stochastic processes (dispersal and drift), although deterministic factors (temperature and organic input) are also important. Our findings enhance our mechanistic understanding of the global diversity and biogeography of activated sludge bacterial communities within a theoretical ecology framework and have important implications for microbial ecology and wastewater treatment processes.


Asunto(s)
Biodiversidad , Microbiota , Aguas del Alcantarillado/microbiología , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , ADN Bacteriano/genética , Geografía , Microbiota/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Purificación del Agua/estadística & datos numéricos
5.
Sci Total Environ ; 673: 435-444, 2019 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-30991333

RESUMEN

The transformation of dissolved organic nitrogen (DON) in the drinking water treatment plants could be closely associated with nitrogenous disinfection by-product (N-DBP) formation. In this study, we have assessed the molecular transformation of DON and its impact on N-DBP formation in a full scale drinking water treatment plant. Based on the result of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis, DON compounds with low molecular weight (<1 kDa) were classified as CHON, CHON2 and CHON3 according to the number of nitrogen atoms. Via the analytical window of van Krevelen diagrams, we found that the molecular structural features of CHON, CHON2 and CHON3 were not altered before the chlorination process. In detail, the CHON2 and CHON3 compositions were concentrated on the regions assigned to a lignin-structure while CHON compositions were also distributed in other compounds including proteins, carbohydrates and tannin. Furthermore, CHON formation was more difficult to be removed before the V-filter process. For N-DBP, chlorine-containing DON (Cl-DON) composition was likely to be removed through flocculation and sedimentation processes, whereas N-nitrosamine compounds were removed in V-filter and biological activated carbon filter processes. The health risks of aromatic structure N-nitrosamines due to the pre-chlorination of the raw water should be further studied.


Asunto(s)
Agua Potable/química , Monitoreo del Ambiente , Nitrógeno/análisis , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , China , Desinfección , Purificación del Agua/estadística & datos numéricos , Abastecimiento de Agua/estadística & datos numéricos
6.
J Environ Sci (China) ; 81: 52-67, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30975330

RESUMEN

Disinfection is an indispensable water treatment process for killing harmful pathogens and protecting human health. However, the disinfection has caused significant public concern due to the formation of toxic disinfection by-products (DBPs). Lots of studies on disinfection and DBPs have been performed in the world since 1974. Although related studies in China started in 1980s, a great progress has been achieved during the last three decades. Therefore, this review summarized the main achievements on disinfection and DPBs studies in China, which included: (1) the occurrence of DBPs in water of China, (2) the identification and detection methods of DBPs, (3) the formation mechanisms of DBPs during disinfection process, (4) the toxicological effects and epidemiological surveys of DBPs, (5) the control and management countermeasures of DBPs in water disinfection, and (6) the challenges and chances of DBPs studies in future. It is expected that this review would provide useful information and reference for optimizing disinfection process, reducing DBPs formation and protecting human health.


Asunto(s)
Desinfectantes/análisis , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , China , Desinfección/estadística & datos numéricos , Purificación del Agua/estadística & datos numéricos , Abastecimiento de Agua/métodos , Abastecimiento de Agua/estadística & datos numéricos
7.
Sci Total Environ ; 669: 777-784, 2019 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-30897436

RESUMEN

Antibiotic resistance is extensively detected in drinking water sources, threatening its safety and human health, which deserves further attention to the removal of antibiotic resistance genes (ARGs) in the drinking water system. In this study, the occurrence and reduction of integrase gene intI1 and forty-one ARG subtypes, which confers resistance to six antibiotic classes (ß-lactam, aminoglycoside, macrolide, tetracycline, sulfonamide, and quinolone), were investigated in a drinking water treatment plant (DWTP). Seventeen ARG subtypes with absolute concentrations ranging from 1.4 × 100 to 7.3 × 105 and 3.9 × 104 genes/mL (intI1) were detected in the raw water; and sul1 and sul2 were the two dominant ARG subtypes. Overall, the whole DWTPs achieved 0.03-2.4 log reduction of ARGs compared with those presented in raw water. The reduction efficiencies of sul1, strA, and intI1 were the highest (1.0-2.4 log) in both conventional and advanced processes. However, the levels of sul1, sul2, and ermC still remained high (1.3 × 100-1.9 × 104 genes/mL) in finished water. The treatment units, including pre-flocculation/sedimentation/sand filtration, and ozonation units, were beneficial for the reduction of ARGs, which was mostly ascribed to the decline in biomass and the strong oxidizing properties of ozone. However, the reduction effect was subsequently counteracted by the granular activated carbon and chlorination units. This study provides basic data for ARG pollution in the drinking water system, and suggests that ARGs persist in drinking water, even after conventional chlorination or advanced treatment processes, highlighting the need for new and efficient water purification technologies.


Asunto(s)
Agua Potable/microbiología , Farmacorresistencia Microbiana/genética , Microbiología del Agua , Purificación del Agua/métodos , Monitoreo del Ambiente , Genes Microbianos , Purificación del Agua/estadística & datos numéricos
8.
Sci Total Environ ; 669: 785-797, 2019 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-30897437

RESUMEN

In recent years, there has been a growing interest on the occurrence of antibiotic-resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in treated and untreated drinking water. ARB and ARGs pose a public health concern when they transfer antibiotic resistance (AR) to human pathogens. However, it is still unclear whether the presence of environmental ARB and ARGs in source water, drinking water treatment plants, and drinking water distribution systems has any significant impact on human exposure to pathogenic ARB. In this review, we critically examine the occurrence of AR in groundwater, surface water, and treated distributed water. This offered a new perspective on the human health threat posed by AR in drinking water and helped in crafting a strategy for monitoring AR effectively. Using existing data on removal of ARB and ARGs in drinking water treatment plants, presence and proliferation of AR in drinking water distribution systems, and mechanisms and pathways of AR transfer in drinking water treatment plants, we conclude that combining UV-irradiation with advanced oxidative processes (such as UV/chlorine, UV/H2O2, and H2O2/UV/TiO2) may enhance the removal of ARB and ARGs, while disinfection may promote horizontal gene transfer from environmental ARB to pathogens. The potential human health risks of AR were determined by examining human exposure to antibiotic resistant human pathogens and re-evaluating waterborne disease outbreaks and their links to environmental AR. We concluded that integrating disease outbreak analysis, human exposure modelling, and clinical data could provide critical information that can be used to estimate the dose-response relationships of pathogenic ARB in drinking water, which is required for accurate risk assessments.


Asunto(s)
Agua Potable/microbiología , Farmacorresistencia Bacteriana/genética , Microbiología del Agua , Purificación del Agua/métodos , Desinfección , Transferencia de Gen Horizontal , Genes Bacterianos , Humanos , Peróxido de Hidrógeno , Oxidación-Reducción , Rayos Ultravioleta , Purificación del Agua/estadística & datos numéricos
9.
Environ Monit Assess ; 191(3): 141, 2019 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-30734086

RESUMEN

Preoxidation is an important unit process which can partially remove organic and microbial contaminations. Due to the high concentrations of organic matter entering the water treatment plant, originating from surface water resources, preoxidation by using chlorinated compounds may increase the possibility of trihalomethane (THM) formation. Therefore, in order to reduce the concentration of THMs, different alternatives such as injection of potassium permanganate are utilized. The present study attempts to investigate the efficiency of the microbial removal from raw water entering the water treatment plant No. 1 in Mashhad, Iran, through various doses of potassium permanganate. Then, an examination of the predictive models is done in order to indicate the residual Escherichia coli and total coliform resulted from injecting the potassium permanganate. Finally, the coefficients of the proposed models were optimized using the genetic algorithm. The results of the study show that 0.5 mg L-1 of potassium permanganate would remove 50% of total coliform as well as 80% of Escherichia coli in the studied water treatment plant. Also, assessing the performance of different models in predicting the residual microbial concentration after injection of potassium permanganate suggests the Gaussian model as the one resulting the highest conformity. Moreover, it can be concluded that employing smart models leads to an optimization of the injected potassium permanganate at the levels of 27% and 73.5%, for minimum and maximum states during different seasons of a year, respectively.


Asunto(s)
Modelos Teóricos , Permanganato de Potasio/metabolismo , Contaminación Química del Agua/estadística & datos numéricos , Purificación del Agua/métodos , Biodegradación Ambiental , Monitoreo del Ambiente , Irán , Oxidantes , Oxidación-Reducción , Permanganato de Potasio/análisis , Trihalometanos , Agua , Microbiología del Agua , Contaminantes Químicos del Agua/análisis , Purificación del Agua/estadística & datos numéricos
10.
Int J Environ Health Res ; 29(6): 686-701, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30694087

RESUMEN

A consistent and correct use of water treatment options is fundamental for health gain from point-of-use water chlorination. In Ethiopia, empirical evidence about the consistent use and preference for by end users is scarce. The current study is intended to explore these issues using Waterguard and Bishan Gari in Kersa Health and Demographic Surveillance Site, Eastern Ethiopia. Data were collected every 2 week for 4 months and analyzed using mixed effects logistic regression. Of 377 households, 31% consistently used Waterguard and Bishan Gari in all the study waves. Product use over time within a household varied based on the perception about the products and the type of products each household received. From the exit assessment, 56% of households stated a preference for Waterguard significantly different from 5.6% of households that stated a preference for Bishan Gari. An intervention for consistent use beyond their availability and accessibility to end users is needed.


Asunto(s)
Agua Potable/normas , Purificación del Agua/métodos , Purificación del Agua/estadística & datos numéricos , Cloro/análisis , Agua Potable/química , Etiopía , Composición Familiar , Humanos , Modelos Logísticos , Características de la Residencia , Salud Rural , Encuestas y Cuestionarios , Purificación del Agua/instrumentación
11.
Environ Health Prev Med ; 23(1): 46, 2018 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-30261840

RESUMEN

BACKGROUND: Diarrheal disease attributable to water and sanitation can be prevented using point-of-use water treatment. In Ethiopia, a small number of households treat water at point-of-use with appropriate methods. However, evidence on factors associated with household use of these treatment methods is scarce. Therefore, this study is intended to explore the household use of appropriate point-of-use water treatment and associated factors in Ethiopia. METHODS: The data of 2005, 2011, and 2016 Ethiopian demographic and health surveys were used for analysis. Households reportedly treating water with bleach, boiling, filtration, and solar disinfection in each survey are considered as treating with appropriate treatment methods. Household water treatment with these treatment methods and factors associated was assessed using bivariate and multivariable regression. In addition, a region level difference in the treatment use was assessed by using multilevel modeling. RESULTS: The number of households that reported treating water with appropriate water treatment methods was 3.0%, 8.2%, and 6.5% respectively in 2005, 2011, and 2016. Household heads with higher education had 5.99 (95% CI = 3.48, 10.33), 3.61 (95% CI = 2.56, 5.07), and 3.43 (95% CI = 2.19, 6.37) times higher odds of using the treatment methods respectively in 2005, 2011, and 2016 compared to household heads who had no education. There was a significantly high number of households that used appropriate water treatment methods in 2011 (AOR = 2.78, 95% CI = 2.16, 3.57) and 2016 (AOR = 2.18, 95% CI = 1.64, 3.89) compared to 2005 data. In pooled data analysis, the reported use of the treatment methods is associated with household head education, residency, drinking water sources, and owning radio and television. From a multilevel modeling, within-region variation is higher than between-region variations in the use of treatment methods in each survey. CONCLUSIONS: Below 10% of households reportedly treating water at point-of-use in each survey attributable to different factors. Designing intervention strategies for wide-scale use of treatment methods at the country level is fundamental.


Asunto(s)
Purificación del Agua/métodos , Purificación del Agua/estadística & datos numéricos , Adolescente , Adulto , Etiopía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Factores Socioeconómicos , Encuestas y Cuestionarios , Purificación del Agua/normas , Abastecimiento de Agua/estadística & datos numéricos , Adulto Joven
12.
Water Sci Technol ; 78(1-2): 37-48, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30101787

RESUMEN

Algal photosynthesis plays a key role in the removal mechanisms of waste stabilization ponds (WSPs), which is indicated in the variations of three parameters, dissolved oxygen, pH, and chlorophyll a. These variations can be considerably affected by extreme climatic conditions at high altitude. To investigate these effects, three sampling campaigns were conducted in a high-altitude WSP in Cuenca (Ecuador). From the collected data, the first application of structure equation modeling (SEM) on a pond system was fitted to analyze the influence of high-altitude characteristics on pond performance, especially on the three indicators. Noticeably, air temperature appeared as the highest influencing factors as low temperature at high altitude can greatly decrease the growth rate of microorganisms. Strong wind and large diurnal variations of temperature, 7-20 °C, enhanced flow efficiency by improving mixing inside the ponds. Intense solar radiation brought both advantages and disadvantages as it boosted oxygen level during the day but promoted algal overgrowth causing oxygen depletion during the night. From these findings, the authors proposed insightful recommendations for future design, monitoring, and operation of high-altitude WSPs. Moreover, we also recommended SEM to pond engineers as an effective tool for better simulation of such complex systems like WSPs.


Asunto(s)
Estanques , Eliminación de Residuos Líquidos/estadística & datos numéricos , Purificación del Agua/estadística & datos numéricos , Tiempo (Meteorología) , Altitud , Ecuador , Modelos Biológicos , Oxígeno/metabolismo , Energía Solar , Temperatura Ambiental
13.
Sci Total Environ ; 628-629: 1178-1190, 2018 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-30045540

RESUMEN

Presently, concentrations of fecal indicator bacteria (FIB) in raw water sources are not known before water undergoes treatment, since analysis takes approximately 24h to produce results. Using data on water quality and environmental variables, models can be used to predict real time concentrations of FIB in raw water. This study evaluates the potentials of zero-inflated regression models (ZI), Random Forest regression model (RF) and adaptive neuro-fuzzy inference system (ANFIS) to predict the concentration of FIB in the raw water source of a water treatment plant in Norway. The ZI, RF and ANFIS faecal indicator bacteria predictive models were built using physico-chemical (pH, temperature, electrical conductivity, turbidity, color, and alkalinity) and catchment precipitation data from 2009 to 2015. The study revealed that pH, temperature, turbidity, and electrical conductivity in the raw water were the most significant factors associated with the concentration of FIB in the raw water source. Compared to the other models, the ANFIS model was superior (Mean Square Error=39.49, 0.35, 0.09, 0.23CFU/100ml respectively for coliform bacteria, E. coli, Intestinal enterococci and Clostridium perfringens) in predicting the variations of FIB in the raw water during model testing. However, the model was not capable of predicting low counts of FIB during both training and testing stages of the models. The ZI and RF models were more consistent when applied to testing data, and they predicted FIB concentrations that characterized the observed FIB concentrations. While these models might need further improvement, results of this study indicate that ZI and RF regression models have high prospects as tools for the real-time prediction of FIB in raw water sources for proactive microbial risk management in water treatment plants.


Asunto(s)
Agua Potable/microbiología , Monitoreo del Ambiente/métodos , Modelos Estadísticos , Microbiología del Agua , Contaminación del Agua/estadística & datos numéricos , Enterococcus , Escherichia coli , Noruega , Purificación del Agua/métodos , Purificación del Agua/estadística & datos numéricos , Calidad del Agua
14.
Water Environ Res ; 90(8): 738-747, 2018 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-30031407

RESUMEN

To enable small communities to benchmark the energy efficiency of their water resource recovery facilities (also known as wastewater treatment facilities), multiple linear regression models of electric and overall energy intensity (kWh/m3) were created using data from Nebraska and Pennsylvania. Key variables found to be significant include: facility type, supplemental energy usage for sludge treatment, average flow, percent design flow, climate controlled floor area, effluent NH3-N, and influent CBOD5. The results show that energy use models for small systems differ from those for large facilities and that regulatory changes can affect energy usage. Step changes in the data for facilities that changed operators highlight the importance of operational decisions on energy efficiency for small facilities serving fewer than 10,000 people. Differences were observed between the models of data from specific states. Although these models may not include all factors that account for variability in energy use, they can provide a reference benchmark for small WRRFs.


Asunto(s)
Benchmarking , Conservación de los Recursos Energéticos/economía , Instalaciones de Eliminación de Residuos/economía , Eliminación de Residuos Líquidos/economía , Purificación del Agua/estadística & datos numéricos , Modelos Teóricos , Nebraska , Purificación del Agua/economía , Recursos Hídricos
15.
Sci Total Environ ; 643: 936-945, 2018 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-29960230

RESUMEN

The work addresses the effect of total suspended solids (TSS) on disinfection by peracetic acid (PAA) concerning both PAA decay and bacterial inactivation kinetics. The effect of TSS on PAA decay was evaluated at five TSS concentrations (5, 40, 80, 120 and 160 mg/L), obtained from stock TSS solutions prepared from activated sludge samples. The influence of the soluble matter associated to the suspended solids on PAA decay was evaluated separately, using the same stock TSS solution after the removal of solids by filtration. The contributions of suspended and soluble fractions were found to be independent, and a predictive model formed by two additive sub-models was proposed to describe the overall PAA decay kinetics. Moreover, an uncertainty analysis was performed by a series of Monte Carlo simulations to propagate the uncertainties associated to the coefficients of the model. Then, the disinfectant dose (mg/L min) was highlighted as the main parameter determining disinfection efficiency on a pure culture of E. coli and an inactivation kinetic model was developed based on the response of E. coli to various PAA doses. Finally, the effect of TSS (40 and 160 mg/L) on the inactivation of free-swimming E. coli was investigated at two PAA doses (5 and 20 mg/L min). TSS reduced inactivation extent an average of 0.4 logs at 5 mg/L min and 1.5 logs at 20 mg/L min. It was hypothesized that this might be due to the formation of bacteria aggregates as defense mechanism against disinfection, enhanced by the presence of solids.


Asunto(s)
Desinfectantes/metabolismo , Ácido Peracético/metabolismo , Purificación del Agua/métodos , Desinfección , Escherichia coli , Cinética , Modelos Estadísticos , Purificación del Agua/estadística & datos numéricos
16.
MMWR Morb Mortal Wkly Rep ; 67(19): 547-551, 2018 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-29771872

RESUMEN

Outbreaks associated with exposure to treated recreational water can be caused by pathogens or chemicals in venues such as pools, hot tubs/spas, and interactive water play venues (i.e., water playgrounds). During 2000-2014, public health officials from 46 states and Puerto Rico reported 493 outbreaks associated with treated recreational water. These outbreaks resulted in at least 27,219 cases and eight deaths. Among the 363 outbreaks with a confirmed infectious etiology, 212 (58%) were caused by Cryptosporidium (which causes predominantly gastrointestinal illness), 57 (16%) by Legionella (which causes Legionnaires' disease, a severe pneumonia, and Pontiac fever, a milder illness with flu-like symptoms), and 47 (13%) by Pseudomonas (which causes folliculitis ["hot tub rash"] and otitis externa ["swimmers' ear"]). Investigations of the 363 outbreaks identified 24,453 cases; 21,766 (89%) were caused by Cryptosporidium, 920 (4%) by Pseudomonas, and 624 (3%) by Legionella. At least six of the eight reported deaths occurred in persons affected by outbreaks caused by Legionella. Hotels were the leading setting, associated with 157 (32%) of the 493 outbreaks. Overall, the outbreaks had a bimodal temporal distribution: 275 (56%) outbreaks started during June-August and 46 (9%) in March. Assessment of trends in the annual counts of outbreaks caused by Cryptosporidium, Legionella, or Pseudomonas indicate mixed progress in preventing transmission. Pathogens able to evade chlorine inactivation have become leading outbreak etiologies. The consequent outbreak and case counts and mortality underscore the utility of CDC's Model Aquatic Health Code (https://www.cdc.gov/mahc) to prevent outbreaks associated with treated recreational water.


Asunto(s)
Brotes de Enfermedades/estadística & datos numéricos , Recreación , Microbiología del Agua , Purificación del Agua/estadística & datos numéricos , Humanos , Estados Unidos/epidemiología
17.
Sci Total Environ ; 619-620: 1330-1339, 2018 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-29734610

RESUMEN

Drinking water treatment plants rely on purification of contaminated source waters to provide communities with potable water. One group of possible contaminants are enteric viruses. Measurement of viral quantities in environmental water systems are often performed using polymerase chain reaction (PCR) or quantitative PCR (qPCR). However, true values may be underestimated due to challenges involved in a multi-step viral concentration process and due to PCR inhibition. In this study, water samples were concentrated from 25 drinking water treatment plants (DWTPs) across the US to study the occurrence of enteric viruses in source water and removal after treatment. The five different types of viruses studied were adenovirus, norovirus GI, norovirus GII, enterovirus, and polyomavirus. Quantitative PCR was performed on all samples to determine presence or absence of these viruses in each sample. Ten DWTPs showed presence of one or more viruses in source water, with four DWTPs having treated drinking water testing positive. Furthermore, PCR inhibition was assessed for each sample using an exogenous amplification control, which indicated that all of the DWTP samples, including source and treated water samples, had some level of inhibition, confirming that inhibition plays an important role in PCR-based assessments of environmental samples. PCR inhibition measurements, viral recovery, and other assessments were incorporated into a Bayesian model to more accurately determine viral load in both source and treated water. Results of the Bayesian model indicated that viruses are present in source water and treated water. By using a Bayesian framework that incorporates inhibition, as well as many other parameters that affect viral detection, this study offers an approach for more accurately estimating the occurrence of viral pathogens in environmental waters.


Asunto(s)
Agua Potable/virología , Monitoreo del Ambiente , Modelos Estadísticos , Contaminación del Agua/estadística & datos numéricos , Teorema de Bayes , Estados Unidos , Microbiología del Agua , Purificación del Agua/estadística & datos numéricos
18.
J Appl Microbiol ; 125(3): 917-928, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29741280

RESUMEN

AIMS: In biosand filters (BSF), treatment is largely driven by the development of a biolayer (schmutzdecke) which establishes itself during the startup phase. In this study, the effect of changing influent total organic carbon (TOC) loading on the removal efficiency of Vibrio cholerae in laboratory-operated BSFs was quantified. METHODS AND RESULTS: BSFs were charged with high, medium or low TOC influents and removal efficacy and schmutzdecke composition was monitored over 2 months. The highest V. cholerae removal efficiencies were observed in the BSF receiving the lowest TOC. Schmutzdecke composition was found to be influenced by influent TOC, in terms of microbial community structure and amount of extracellular polymeric substance (EPS). CONCLUSIONS: Physical/chemical attachment was shown to be important during startup. The BSF receiving influent water with lower TOC had a higher attachment coefficient than the BSF receiving high TOC water, suggesting more physical/chemical treatment in the lower TOC BSF. The high TOC BSF had more EPS than did the biofilm from the low-TOC BSF, suggesting that schmutzdecke effects may be more significant at high TOC. SIGNIFICANCE AND IMPACT OF THE STUDY: Overall, this study confirms that influent water characteristics will affect BSF treatment efficacy of V. cholerae especially during the startup phase.


Asunto(s)
Incrustaciones Biológicas , Agua Potable/microbiología , Vibrio cholerae/aislamiento & purificación , Purificación del Agua , Carbono , Purificación del Agua/métodos , Purificación del Agua/estadística & datos numéricos
19.
Integr Environ Assess Manag ; 14(4): 447-462, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29603595

RESUMEN

Mediterranean-African countries (MACs) face a major water crisis. The annual renewable water resources are close to the 500 m3 /capita threshold of absolute water scarcity, and water withdrawals exceed total renewable water resources by 30%. Such a low water availability curbs economic development in agriculture, which accounts for 86% of freshwater consumption. The analysis of the current situation of wastewater treatment, irrigation, and water management in MACs and of the research projects targeted to these countries indicates the need for 1) an enhanced capacity to analyze water stress, 2) the development of water management strategies capable of including wastewater reuse, and 3) development of locally adapted water treatment and irrigation technologies. This analysis shaped the MADFORWATER project (www.madforwater.eu), whose goal is to develop a set of integrated technological and management solutions to enhance wastewater treatment, wastewater reuse for irrigation, and water efficiency in agriculture in Egypt, Morocco, and Tunisia. MADFORWATER develops and adapts technologies for the production of irrigation-quality water from drainage canals and municipal, agro-industrial, and industrial wastewaters and technologies for water efficiency and reuse in agriculture, initially validated at laboratory scale, to 3 hydrological basins in the selected MACs. Selected technologies will be further adapted and validated in 4 demonstration plants of integrated wastewater treatment and reuse. Integrated strategies for wastewater treatment and reuse targeted to the selected basins are developed, and guidelines for the development of integrated water management strategies in other basins of the 3 target MACs will be produced. The social and technical suitability of the developed technologies and nontechnological tools in relation to the local context is evaluated with the participation of MAC stakeholders and partners. Guidelines on economic instruments and policies for the effective implementation of the proposed water management solutions in the target MACs will be developed. Integr Environ Assess Manag 2018;14:447-462. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).


Asunto(s)
Agricultura , Reciclaje , Eliminación de Residuos Líquidos/métodos , Eliminación de Residuos Líquidos/estadística & datos numéricos , Purificación del Agua/métodos , Purificación del Agua/estadística & datos numéricos , Egipto , Marruecos , Túnez
20.
J Water Health ; 16(2): 223-232, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29676758

RESUMEN

In September 2016, Médecins Sans Frontières responded to a hepatitis E (HEV) outbreak in Chad by implementing water treatment and hygiene interventions. To evaluate the coverage and use of these interventions, we conducted a cross-sectional study in the community. Our results showed that 99% of households interviewed had received a hygiene kit from us, aimed at improving water handling practice and personal hygiene and almost all respondents had heard messages about preventing jaundice and handwashing. Acceptance of chlorination of drinking water was also very high, although at the time of interview, we were only able to measure a safe free residual chlorine level (free chlorine residual (FRC) ≥0.2 mg/L) in 43% of households. Households which had refilled water containers within the last 18 hours, had sourced water from private wells or had poured water into a previously empty container, were all more likely to have a safe FRC level. In this open setting, we were able to achieve high coverage for chlorination, hygiene messaging and hygiene kit ownership; however, a review of our technical practice is needed in order to maintain safe FRC levels in drinking water in households, particularly when water is collected from multiple sources, stored and mixed with older water.


Asunto(s)
Hepatitis E/epidemiología , Higiene/normas , Purificación del Agua/métodos , Chad/epidemiología , Estudios Transversales , Brotes de Enfermedades , Hepatitis E/prevención & control , Humanos , Purificación del Agua/estadística & datos numéricos , Abastecimiento de Agua/estadística & datos numéricos
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