RESUMO
Background: Dengue fever (DF) is a mosquito-borne illness with substantial economic and societal impact. Understanding laboratory trends of hospitalized Dominican Republic (DR) pediatric patients could help develop screening procedures in low-resourced settings. We sought to describe laboratory findings over time in DR children with DF and DF severity from 2018 to 2020. Methods: Clinical information was obtained prospectively from recruited children with DF. Complete blood count (CBC) laboratory measures were assessed across Days 1-10 of fever. Participants were classified as DF-negative and DF-positive and grouped by severity. We assessed associations of DF severity with demographics, clinical characteristics, and peripheral blood studies. Using linear mixed-models, we assessed if hematologic values/trajectories differed by DF status/severity. Results: A total of 597 of 1101 with a DF clinical diagnosis were serologically evaluated, and 574 (471 DF-positive) met inclusion criteria. In DF, platelet count and hemoglobin were higher on earlier days of fever (p < = 0.0017). Eighty had severe DF. Severe DF risk was associated with thrombocytopenia, intraillness anemia, and leukocytosis, differing by fever day (p < = 0.001). Conclusions: In a pediatric hospitalized DR cohort, we found marked anemia in late stages of severe DF, unlike the typically seen hemoconcentration. These findings, paired with clinical symptom changes over time, may help guide risk-stratified screenings for resource-limited settings.
Assuntos
Vírus da Dengue , Dengue , Humanos , República Dominicana/epidemiologia , Dengue/epidemiologia , Dengue/sangue , Dengue/virologia , Dengue/diagnóstico , Masculino , Feminino , Pré-Escolar , Contagem de Células Sanguíneas , Lactente , Vírus da Dengue/isolamento & purificação , Criança , Epidemias , Anemia/epidemiologia , Anemia/sangue , Trombocitopenia/epidemiologia , Trombocitopenia/sangue , Trombocitopenia/virologia , Estudos ProspectivosRESUMO
OBJECTIVE: The aim was to describe the characteristics of the transport system of critically ill pediatric patients in the emergency departments (EDs) in Latin America (LA). METHODOLOGY: This is a prospective cross-sectional study in a 1-year period. Patients were recruited on days 1, 7, 14, 21, and 28 of each month in the EDs in LA. We included ill-pediatric patients aged 1 month to 18 years. Patients who needed transfer for a diagnostic study, with arrival mode not by ambulance, or with the impossibility of interviewing the transfer team were excluded from the study. RESULTS: A total of 389 patients were included in the study. The majority were males (57%) with a median age of 49 months (interquartile range, 10-116). Thirty-three percent (129) of transfers had the participation of a coordinating center; 97.1% (375) were carried out by road ambulance, and 84.3% (323) were interhospital transfers, with a mean distance traveled of 83.2 km (SD, 105 km). The main reason for transfer in 88.17% (343) was the need for a more complex health center. The main diagnosis was respiratory distress (71; 18.2%), acute abdomen (70; 18%), Traumatic Brain Injury (33; 8.48%), multiple trauma (32; 8.23%), septic shock (31; 7.9%), and COVID-19-related illness (19; 4.8%). A total of 296 (76.5%) patients had peripheral vascular access, and 171 (44%) patients had oxygen support with 49 (28.6%) having invasive ventilation; the most frequent monitoring method (67.8%) was pulse oximetry, and 83.4% (313) did not record adverse events. Regarding the transfer team, 88% (342) had no specialized personnel, and only 62.4% (243) had a physician on their teams. CONCLUSIONS: In LA, there is great variability in personnel training, equipment for pediatric transport, team composition, and characterization of critical care transport systems. Continued efforts to improve conditions in our countries may help reduce patient morbidity and mortality.
Assuntos
Ambulâncias , Serviço Hospitalar de Emergência , Masculino , Criança , Humanos , Pré-Escolar , Feminino , Estudos Prospectivos , América Latina/epidemiologia , Estudos Transversais , Transferência de Pacientes/métodos , Estado Terminal/epidemiologia , Estado Terminal/terapiaRESUMO
Based Epidemiology (WBE) consists of quantifying biomarkers in sewerage systems to derive real-time information on the health and/or lifestyle of the contributing population. WBE usefulness was vastly demonstrated in the context of the COVID-19 pandemic. Many methods for SARS-CoV-2 RNA determination in wastewater were devised, which vary in cost, infrastructure requirements and sensitivity. For most developing countries, implementing WBE for viral outbreaks, such as that of SARS-CoV-2, proved challenging due to budget, reagent availability and infrastructure constraints. In this study, we assessed low-cost methods for SARS-CoV-2 RNA quantification by RT-qPCR, and performed variant identification by NGS in wastewater samples. Results showed that the effect of adjusting pH to 4 and/or adding MgCl2 (25 mM) was negligible when using the adsorption-elution method, as well as basal physicochemical parameters in the sample. In addition, results supported the standardized use of linear rather than plasmid DNA for a more accurate viral RT-qPCR estimation. The modified TRIzol-based purification method in this study yielded comparable RT-qPCR estimation to a column-based approach, but provided better NGS results, suggesting that column-based purification for viral analysis should be revised. Overall, this work provides evaluation of a robust, sensitive and cost-effective method for SARS-CoV-2 RNA analysis that could be implemented for other viruses, for a wider WEB adoption.
RESUMO
The COVID-19 pandemic has caused a global health crisis, and wastewater-based epidemiology (WBE) has emerged as an important tool to assist public health decision-making. Recent studies have shown that the SARS-CoV-2 RNA concentration in wastewater samples is a reliable indicator of the severity of the pandemic for large populations. However, few studies have established a strong correlation between the number of infected people and the viral concentration in wastewater due to variations in viral shedding over time, viral decay, infiltration, and inflow. Herein we present the relationship between the number of COVID-19-positive patients and the viral concentration in wastewater samples from three different hospitals (A, B, and C) in the city of Belo Horizonte, Minas Gerais, Brazil. A positive and strong correlation between wastewater SARS-CoV-2 concentration and the number of confirmed cases was observed for Hospital B for both regions of the N gene (R = 0.89 and 0.77 for N1 and N2, respectively), while samples from Hospitals A and C showed low and moderate correlations, respectively. Even though the effects of viral decay and infiltration were minimized in our study, the variability of viral shedding throughout the infection period and feces dilution due to water usage for different activities in the hospitals could have affected the viral concentrations. These effects were prominent in Hospital A, which had the smallest sewershed population size, and where no correlation between the number of defecations from COVID-19 patients and viral concentration in wastewater was observed. Although we could not determine trends in the number of infected patients through SARS-CoV-2 concentrations in hospitals' wastewater samples, our results suggest that wastewater monitoring can be efficient for the detection of infected individuals at a local level, complementing clinical data.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , COVID-19/epidemiologia , Pandemias , Águas Residuárias , Brasil/epidemiologia , RNA Viral , HospitaisRESUMO
We performed an observational cohort study to assess associations between genetic factors of dengue fever (DF) severity in children in the Dominican Republic. A total of 488 participants had serologically confirmed DF. We replicated the association between the IFIH1 gene (rs1990760) and severe DF (n = 80/488, p = 0.006) and identified novel associations needing further investigation.
Assuntos
Dengue , Dengue Grave , Humanos , Criança , Dengue/diagnóstico , Dengue/epidemiologia , República Dominicana/epidemiologia , Estudos de Coortes , GenômicaRESUMO
Coronavirus pandemic started in March 2020 and since then has caused millions of deaths worldwide. Wastewater-based epidemiology (WBE) can be used as an epidemiological surveillance tool to track SARS-CoV-2 dissemination and provide warning of COVID-19 outbreaks. Considering that there are public places that could be potential hotspots of infected people that may reflect the local epidemiological situation, the presence of SARS-CoV-2 RNA was analyzed by RT-qPCR for approximately 16 months in sewage samples from five public places located in the metropolitan area of Belo Horizonte, MG, Brazil: the sewage treatment plant of Confins International Airport (AIR), the main interstate bus terminal (BUS), an upscale shopping centre (SHC1), a popular shopping centre (SHC2) and a university institute (UNI). The results were compared to those of the influent sewage of the two main sewage treatment plants of Belo Horizonte (STP1 and STP2). Viral monitoring in the STPs proved to be an useful regional surveillance tool, reflecting the trends of COVID-19 cases. However, the viral concentrations in the samples from the selected public places were generally much lower than those of the municipal STPs, which may be due to the behaviour of the non-infected or asymptomatic people, who are likely to visit these places relatively more than the symptomatic infected ones. Among these places, the AIR samples presented the highest viral concentrations and concentration peaks were observed previously to local outbreaks. Therefore, airport sewage monitoring can provide an indication of the regional epidemiological situation. For the other places, particularly the UNI, the results suggested a greater potential to detect the infection and trace cases especially among employees and regular attendees. Taken together, the results indicate that for a regular and permanent sentinel sewage surveillance the sewage from STPs, AIR and UNI could be monitored.
Assuntos
COVID-19 , COVID-19/epidemiologia , Humanos , Pandemias , RNA Viral , SARS-CoV-2 , Esgotos , Águas ResiduáriasRESUMO
Peru has been severely affected by the COVID-19 pandemic. By January 2022, Peru had surpassed 200â¯000 COVID-19 deaths, constituting the highest death rate per capita worldwide. Peru has had several limitations during the pandemic: insufficient testing access, limited contact tracing, a strained medical infrastructure, and many economic hurdles. These limitations hindered the gathering of accurate information about infected individuals with spatial resolution in real time, a critical aspect of effectively controlling the pandemic. Wastewater monitoring for SARS-CoV-2 RNA offered a promising alternative for providing needed population-wide information to complement health care indicators. In this study, we demonstrate the feasibility and value of implementing a decentralized SARS-CoV-2 RNA wastewater monitoring system to assess the spatiotemporal distribution of COVID-19 in three major cities in Peru: Lima, Callao, and Arequipa. Our data on viral loads showed the same trends as health indicators such as incidence and mortality. Furthermore, we were able to identify hot spots of contagion within the surveyed urban areas to guide the efforts of health authorities. Viral decay in the sewage network of the cities studied was found to be negligible (<2%). Overall, our results support wastewater monitoring for SARS-CoV-2 as a valuable and cost-effective tool for monitoring the COVID-19 pandemic in the Peruvian context.
RESUMO
Sustainable sewage treatment plants (STPs) have been intensively investigated in search for low-cost, environmental-friendly options. Anaerobic-aerobic treatment solutions, as upflow anaerobic sludge blanket (UASB) reactors followed by high rate algal ponds (HRAP) have already proved to be efficient for pollutants and micropollutants removal, as well as for energy recovery from the co-digestion of raw sewage and microalgal biomass. Since microalgae cells have complex structures that make them resistant to anaerobic digestion, pre-treatment techniques may be applied to improve microalgal biomass solubilisation and methane yield. Among the thermal pre-treatments, the use of solar energy for biomass solubilisation has yet to be investigated. Therefore, this study aimed at evaluating the performance of a solar thermal microalgal biomass pre-treatment prior to the anaerobic co-digestion with raw sewage, comparing a UASB reactor feed only raw sewage and other UASB reactor feed with raw sewage and pre-treated microalgal biomass. The results showed that, the solar pre-treatment step reached an organic matter solubilisation of 32% (COD). Furthermore, the methane yield was increased by 45% (from 81 to 117 NL CH4 kg-1 COD), after the anaerobic co-digestion with pre-treated microalgae as compared to the mono-digestion of raw sewage, indicating significant difference between the evaluated UASB reactors. The energy assessment showed a positive energy balance, as the total energy produced was twice the energy consumed in the system.
Assuntos
Microalgas , Esgotos , Anaerobiose , Biomassa , Reatores Biológicos , Digestão , Metano , Eliminação de Resíduos LíquidosRESUMO
Brazil has become one of the epicentres of the COVID-19 pandemic, with cases heavily concentrated in large cities. Testing data is extremely limited and unreliable, which restricts health authorities' ability to deal with the pandemic. Given the stark demographic, social and economic heterogeneities within Brazilian cities, it is important to identify hotspots so that the limited resources available can have the greatest impact. This study shows that decentralised monitoring of SARS-CoV-2 RNA in sewage can be used to assess the distribution of COVID-19 prevalence in the city. The methodology developed in this study allowed the identification of hotspots by comprehensively monitoring sewers distributed through Belo Horizonte, Brazil's third largest city. Our results show that the most vulnerable neighbourhoods in the city were the hardest hit by the pandemic, indicating that, for many Brazilians, the situation is much worse than reported by official figures.
Assuntos
COVID-19 , Pandemias , SARS-CoV-2/isolamento & purificação , Esgotos/virologia , Brasil/epidemiologia , COVID-19/epidemiologia , Humanos , Prevalência , RNA ViralRESUMO
This study aims to evaluate micropollutant occurrence and removal in a low-middle income country (LMIC) by investigating the occurrence of 28 chemicals from different classes (triclosan, 15 polycyclic aromatic hydrocarbons (PAHs), 4 estrogens and 8 polybrominated diphenyl ether (PBDE) congeners) in three technologically diverse full-scale Brazilian wastewater treatment plants (WWTPs). These chemicals were detected at concentrations similar to those reported in other low-middle income countries (LMICs) and high-income countries (HICs) (0.1-49 µg/L) indicating their widespread use globally and the need for more studies in LMICs that are typically characterized by relatively inadequate wastewater treatment barriers. Among the three different WWTPs investigated for removal of these chemicals, the least energy intensive system, waste stabilization ponds (WSPs), was the most effective (95-99%) compared to the activated sludge (79-94%), and Up-flow sludge blanket reactor (UASB) with trickling filters system (89-95%). These results highlight the potential of WSPs for micropollutant removal-especially in warm climates. However, the effluent from all three WWTP could pose a risk to aquatic organisms when discharged into the receiving waters as the effluent concentrations of triclosan, some estrogens, PAHs and BDE 209 were above European environmental quality standards (EQS) or predicted no effect concentration (PNEC values), indicating that receiving water bodies could benefit from further treatment. In combination, these results help to further understand prevailing concentrations of micropollutants globally and fate in current wastewater treatment systems.
Assuntos
Poluentes Químicos da Água , Purificação da Água , Anaerobiose , Brasil , Esgotos , Eliminação de Resíduos Líquidos , Águas Residuárias , Poluentes Químicos da Água/análiseRESUMO
COVID-19 patients can excrete viable SARS-CoV-2 virus via urine and faeces, which has raised concerns over the possibility of COVID-19 transmission via aerosolized contaminated water or via the faecal-oral route. These concerns are especially exacerbated in many low- and middle-income countries, where untreated sewage is frequently discharged to surface waters. SARS-CoV-2 RNA has been detected in river water (RW) and raw wastewater (WW) samples. However, little is known about SARS-CoV-2 viability in these environmental matrices. Determining the persistence of SARS-CoV-2 in water under different environmental conditions is of great importance for basic assumptions in quantitative microbial risk assessment (QMRA). In this study, the persistence of SARS-CoV-2 was assessed using plaque assays following spiking of RW and WW samples with infectious SARS-CoV-2 that was previously isolated from a COVID-19 patient. These assays were carried out on autoclaved RW and WW samples, filtered (0.22 µm) and unfiltered, at 4 °C and 24 °C. Linear and nonlinear regression models were adjusted to the data. The Weibull regression model achieved the lowest root mean square error (RMSE) and was hence chosen to estimate T90 and T99 (time required for 1 log and 2 log reductions, respectively). SARS-CoV-2 remained viable longer in filtered compared with unfiltered samples. RW and WW showed T90 values of 1.9 and 1.2 day and T99 values of 6.4 and 4.0 days, respectively. When samples were filtered through 0.22 µm pore size membranes, T90 values increased to 3.3 and 1.5 days, and T99 increased to 8.5 and 4.5 days, for RW and WW samples, respectively. Remarkable increases in SARS-CoV-2 persistence were observed in assays at 4 °C, which showed T90 values of 7.7 and 5.5 days, and T99 values of 18.7 and 17.5 days for RW and WW, respectively. These results highlight the variability of SARS-CoV-2 persistence in water and wastewater matrices and can be highly relevant to efforts aimed at quantifying water-related risks, which could be valuable for understanding and controlling the pandemic.
Assuntos
COVID-19 , Águas Residuárias , Humanos , RNA Viral , Rios , SARS-CoV-2 , Temperatura , ÁguaRESUMO
The performance of an anoxic-aerobic microalgal-bacterial system treating synthetic food waste digestate at 10 days of hydraulic retention time via nitrification-denitrification under increasing digestate concentrations of 25%, 50%, and 100% (v/v) was assessed during Stages I, II and III, respectively. The system supported adequate treatment without external CO2 supplementation since sufficient inorganic carbon in the digestate was available for autotrophic growth. High steady-state Total Organic Carbon (TOC) and Total Nitrogen (TN) removal efficiencies of 85-96% and 73-84% were achieved in Stages I and II. Similarly, PO43--P removals of 81 ± 15% and 58 ± 4% were recorded during these stages. During Stage III, the average influent concentrations of 815 ± 35 mg TOC·L-1, 610 ± 23 mg TN·L-1, and 46 ± 11 mg PO43--P·L-1 induced O2 limiting conditions, resulting in TOC, TN and PO43--P removals of 85 ± 3%, 73 ± 3%, and 28 ± 16%, respectively. Digestate concentrations of 25% and 50% favored nitrification-denitrification mechanisms, whereas the treatment of undiluted digestate resulted in higher ammonia volatilization and hampered nitrification-denitrification. In Stages I and II, the microalgal community was dominated by Chlorella vulgaris and Cryptomonas sp., whereas Pseudoanabaena sp. was more abundant during Stage III. Illumina sequencing revealed the presence of carbon and nitrogen transforming bacteria, with dominances of the genera Gemmata, Azospirillum, and Psychrobacter during Stage I, II, and III, respectively. Finally, the high settleability of the biomass (98% of suspended solids removal in the settler) and average C (42%), N (7%), P (0.2%), and S (0.4%) contents recovered in the biomass confirmed its potential for agricultural applications, contributing to a closed-cycle management of food waste.
Assuntos
Chlorella vulgaris , Microalgas , Eliminação de Resíduos , Reatores Biológicos , Desnitrificação , Alimentos , Nitrificação , Nitrogênio , Eliminação de Resíduos Líquidos , Águas ResiduáriasRESUMO
The data presented in this paper are related to the research article "Ammonia recovery from food waste digestate using solar heat-assisted stripping-absorption" [1]. The raw and filtered data are associated to daily monitoring of NH4 concentration of food waste digestate, pH of digestate and absorption solution and temperature of food waste digestate throughout experiments at different conditions. In addition, data of temperature monitoring in different points of solar-heat assisted stripping-absorption device are presented. The data could help further studies aiming to improve this system. The detailed data of these experiments could help to improve the performance and to reduce costs of nitrogen recovery from digestate using stripping-absorption technology.
RESUMO
Human enteric pathogens are a major global concern, as they are responsible for thousands of preventable deaths every year. New pathogens in wastewater are constantly emerging. For example, SARS-CoV-2 has been recently detected in domestic sewage and primary sludge. Knowledge about the reduction of viruses in wastewater treatment and their partitioning between the treated liquid effluent versus the sludge or biosolids is still very scarce, especially in countries with emerging economies and tropical climates. Upflow anaerobic sludge blanket (UASB) reactors are among the top three most commonly used technologies for the treatment of sewage in Latin America and the Caribbean, and their use has become increasingly common in many other low- and middle-income countries. High-rate algal ponds (HRAP) are regarded as a sustainable technology for the post-treatment of UASB effluent. This study evaluated the overall reduction and the liquid-solid partitioning of somatic coliphages, F-specific coliphages, and E. coli in a pilot-scale system comprised of a UASB reactor followed by HRAPs treating real wastewater. Average log removal for somatic and F-specific coliphages were 0.40 and 0.56 for the UASB reactor, and 1.15 and 1.70 for HRAPs, respectively. The overall removal of both phages in the system was 2.06-log. Removal of E. coli was consistently higher. The number of viruses leaving the system in the UASB solids and algal biomass was less than 10% of the number leaving in the clarified liquid effluent. The number of E. coli leaving the system in solids residuals was estimated to be approximately one order of magnitude higher than the number of E. coli leaving in the liquid effluent. Results from this study demonstrate the suitability of UASB-HRAP systems to reduce viral and bacterial indicators from domestic sewage and the importance of adequately treating sludge for pathogen reduction before they are used as biosolids.
Assuntos
COVID-19 , Esgotos , Anaerobiose , Reatores Biológicos , Região do Caribe , Escherichia coli , Humanos , Lagoas , SARS-CoV-2 , Eliminação de Resíduos LíquidosRESUMO
Heat treatment, or thermal disinfection, is one of the simplest disinfection methods, and is widely used in the water, sanitation, and food sectors, especially in low resource settings. Pathogen reductions achieved during heat treatment are influenced by a combination of temperature and exposure time. The objective of this paper was to construct updated time-temperature pathogen inactivation curves to define "safety zones" for the reduction of four pathogen groups (bacteria, viruses, protozoan (oo)cysts, and helminth eggs) during heat treatment in a variety of matrices. A systematic review and meta-analysis were conducted to determine the times needed to achieve specified levels of pathogen reduction at different temperatures. Web of Science was searched using a Boolean string to target studies of heat treatment and pasteurization systems that exposed pathogens in water, wastewater, biosolids, soil, or food matrices to temperatures between 20 °C and 95 °C. Data were extracted from tables or figures and regression was used to assess the relationship between time and temperature. Our findings indicate that the temperatures and times needed to achieve a 1-log10 reduction of all pathogen groups are likely higher and longer, respectively, than previously reported. The type of microorganism and the matrix significantly impact T90 values reported at different temperatures. At high temperatures, the time-temperature curves are controlled by thermally stable viruses such as hepatitis A virus. Data gaps include the lack of data on protozoa, and the lack of data on all pathogen groups at low temperatures, for long exposure times, and with high log10 reductions. The findings from this study can be used by engineers, food safety specialists for the planning and design of engineered water, sanitation, and food pasteurization and treatment systems.
Assuntos
Pasteurização , Vírus , Desinfecção , Microbiologia de Alimentos , Temperatura Alta , TemperaturaRESUMO
The highest costs of stripping-absorption processes for ammonia recovery are related to energy (for heating and air supply) and chemical addition (for pH adjustment). In this paper, a simplified system that used no chemicals, and a renewable source of energy for heating, was tested to recover nitrogen as ammonium sulfate from food waste digestate. pH adjustment was achieved by CO2 stripping, and vacuum tube solar collectors were used to provide heating. The effect of different temperatures (25 °C and 45 °C) and gas to liquid ratios (1700 and 2600) on ammonia removal and recovery were assessed. Ammonia removal efficiencies higher than 91% were achieved for all evaluated experimental conditions. The solar heater showed adequate capacity to increase the temperature of the liquid digestate by 21 °C and maintain the temperature at 45 °C throughout the experiment. Tests carried out at 45 °C achieved the highest ammonia removal efficiency (98%) at the lowest evaluated G/L ratio (1700). Better absorption efficiencies could potentially have been achieved if lower inlet airflow rates and packing material had been used in the absorption column.
Assuntos
Amônia , Eliminação de Resíduos , Alimentos , Temperatura Alta , Nitrogênio , Eliminação de Resíduos LíquidosRESUMO
Using the biogas generated from organic waste anaerobic treatment to produce polyhydroxyalkanoates (PHAs) has emerged as an attractive alternative to heat and power generation (CHP) in waste treatment plants. The sustainability of biogas combustion for CHP, biogas bioconversion into PHA and a combination of both scenarios was compared in terms of environmental impact, process economics and social responsibility according to the IChemE Sustainability Metrics. Although PHA production presented higher investment and operational costs, a comparable economic performance was observed in all biogas valorization scenarios regarding net present value (0.77 M) and internal rate of return (6.4 ± 0.2%) due to the higher market value of biopolymers. The PHA production entailed a significant reduction of atmospheric acidification and odor emissions compared to CHP despite showing higher land, water, chemicals and energy requirements. Job creation associated to biopolymer industry and the increasing public demand for bioproducts were identified as fundamental aspects for enhancing social and local acceptance of waste processing facilities. This study demonstrated that PHA production from biogas constitutes nowadays a realistic alternative to CHP in waste treatment plants and that PHA can be produced at a competitive market price when biogas is used for internal energy provision (4.2 ·kg-1 PHA).
Assuntos
Poli-Hidroxialcanoatos/química , Eliminação de Resíduos/métodos , Biocombustíveis , Biopolímeros , Reatores Biológicos , Conservação dos Recursos NaturaisRESUMO
Detection of the SARS-CoV-2 virus in stools and sewage has recently been reported, raising the hypothesis of faecal-oral transmission. If confirmed, this could have far-reaching consequences for public health and for pandemic control strategies. In this paper, we argue that a comprehensive and more nuanced analysis is required to test this hypothesis, taking into consideration both environmental dynamics and the persistence of viral infectivity. First, we examine the evidence regarding the presence of the virus in stools and sewage. Then we discuss the current framework of disease transmission through water and excreta and how the transmission of a respiratory disease fits into it. Against this background, we propose a framework to test the faecal-oral hypothesis, unpacking the different environmental routes from faeces to the mouth of a susceptible person. This framework should not be seen as a confirmation of the hypothesis but rather as an expanded view of its complexities, which could help shaping an agenda for research into a number of unanswered questions. Finally, the paper briefly discusses practical implications, based on current knowledge, for containment of the pandemic.
Assuntos
Betacoronavirus , Infecções por Coronavirus , Pandemias , Pneumonia Viral , COVID-19 , Fezes , Humanos , SARS-CoV-2RESUMO
The present study evaluated the removal capacity of a UASB-HRAP treatment system, combining anaerobic and microalgae-based, aerobic treatment, for eleven organic micropollutants present in raw sewage, including pharmaceuticals, estrogens and xenoestrogens. The UASB reactor and the HRAP were operated at a hydraulic retention time (HRT) of 7 h and 8 days, respectively. Influent and effluent samples from the UASB and HRAP were collected periodically. All the target compounds were detected in raw sewage, with an occurrence ranging from 70 to 100%. Removal rates in the UASB reactor were generally incomplete, ranging from no removal (-25.12% for the hormone EE2-ethinylestradiol) to 84.91% (E2 - estradiol). However, the overall performance of the UASB + HRAP system was highly efficient for the majority of the compounds, with removal rates ranging from 64.8% (ibuprofen) to 95% (estrone). Gemfibrozil and bisphenol A were the only exceptions, with overall removal rates of 39% and 43%, respectively. Hormones were the compounds with the highest removal rates in the system.
Assuntos
Reatores Biológicos , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Anaerobiose , Estrogênios , Estrona , Etinilestradiol , Microalgas , Lagoas , EsgotosRESUMO
Upflow anaerobic sludge blanket (UASB) reactors are widely used to treat domestic sewage and frequently require post-treatment. Little is known about the use of high rate algal ponds (HRAP) for post-treating UASB reactors' effluent. This study aimed to evaluate a UASB reactor followed by a HRAP in terms of sewage treatment efficiency and biogas production, during one year at demonstration-scale. The UASB reactor co-treated raw sewage and the harvested microalgal biomass from the HRAP, which was recirculated to the reactor. An identical UASB reactor, treating only raw sewage, was used as control. The results showed an overall removal of 65% COD and 61% N-NH4 in the system. Furthermore, methane yield was increased by 25% after anaerobic co-digestion with microalgae, from 156 to 211 NL CH4 kg-1 VS. An energy assessment was performed and showed a positive energy balance, with a net ratio of 2.11 to the annual average.