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Chlorine is a widely used water disinfectant in humanitarian emergency water supply. However, its effective application can be limited by the uncertainty in initial dose determination. The target free chlorine residual in water should achieve both health objectives and aesthetic considerations, but the varying field conditions and changing source water quality may affect the performance of chlorination strategies. A chlorine dose predictive tool could assist in initial dose determination. To this end, an accurate chlorine decay kinetic model can serve as a strong foundation for developing such a tool. In this study, a literature search identified 7 basic chlorine decay kinetic models that were subsequently tested with 610 different chlorine decay test data (from a semi-systematic literature search and laboratory-generated results). The models were then ranked based on their goodness of fit (R2) and root mean square error. An empirical model, power models and parallel models were found able to fit most decay data with more than half of the regressions resulting in R2 value over 0.97. First order models can achieve R2 value above 0.95 when the data points in the rapid phase are excluded from the model fitting. The power models and parallel models can form a strong basis for developing a chlorine dose predictive tool if the power term and the ratio term (model parameters) can be controlled. An essential next step is to evaluate the relationships between easily obtainable water parameters in the field and the decay term in the models to allow rapid model calibration. GRAPHICAL ABSTRACT
Hongjian Wu; Caetano C. Dorea. Evaluation and application of chlorine decay models for humanitarian emergency water supply contexts. Environmental Technology 2021, 1 -10.
AMA StyleHongjian Wu, Caetano C. Dorea. Evaluation and application of chlorine decay models for humanitarian emergency water supply contexts. Environmental Technology. 2021; ():1-10.
Chicago/Turabian StyleHongjian Wu; Caetano C. Dorea. 2021. "Evaluation and application of chlorine decay models for humanitarian emergency water supply contexts." Environmental Technology , no. : 1-10.
The red mud (RM) has been used as an alternative low-cost adsorbent to remove trace elements, with the adsorption onto sodalite surface described as the main removal mechanism for trace elements. However, recent studies have shown that precipitation might be of great importance for some trace metals removal using natural and thermal activated RM. Therefore, the aim of this study was to identify the main mechanism responsible for Cd(II), Pb(II) and Zn(II) removal from aqueous solutions using natural and activated forms of RM, based on sequential extractions and a precipitation kinetic model was developed. Results showed that the carbonate fraction was responsible for the highest trace elements removal (ca. 85%), with the minerals assemblages precipitated: otavite – CdCO3, cerussite - PbCO3, smithsonite - ZnCO3 and anglesite - PbSO4. The kinetic model showed that the mineral precipitation was limit due to the HCO3− consumption during the formation of new minerals. Hence, this study showed that precipitation was the central mechanism on trace elements removal, regardless the natural or activated forms of RM. This finding raise doubt about the effectiveness of the traditional adsorption isotherms and kinetics models to describe trace metals removal using RM, contributing with new insights for future researches involving these hazardous materials.
Fabiano Tomazini da Conceição; Mariana Scicia Gabriel da Silva; Amauri Antonio Menegário; Maria Lucia Pereira Antunes; Guillermo Rafael Beltran Navarro; Alexandre Martins Fernandes; Caetano Dorea; Rodrigo Braga Moruzzi. Precipitation as the main mechanism for Cd(II), Pb(II) and Zn(II) removal from aqueous solutions using natural and activated forms of red mud. Environmental Advances 2021, 4, 100056 .
AMA StyleFabiano Tomazini da Conceição, Mariana Scicia Gabriel da Silva, Amauri Antonio Menegário, Maria Lucia Pereira Antunes, Guillermo Rafael Beltran Navarro, Alexandre Martins Fernandes, Caetano Dorea, Rodrigo Braga Moruzzi. Precipitation as the main mechanism for Cd(II), Pb(II) and Zn(II) removal from aqueous solutions using natural and activated forms of red mud. Environmental Advances. 2021; 4 ():100056.
Chicago/Turabian StyleFabiano Tomazini da Conceição; Mariana Scicia Gabriel da Silva; Amauri Antonio Menegário; Maria Lucia Pereira Antunes; Guillermo Rafael Beltran Navarro; Alexandre Martins Fernandes; Caetano Dorea; Rodrigo Braga Moruzzi. 2021. "Precipitation as the main mechanism for Cd(II), Pb(II) and Zn(II) removal from aqueous solutions using natural and activated forms of red mud." Environmental Advances 4, no. : 100056.
The concentration of chlorine in water declines as it reacts with various substances, causing decay of the residual free chlorine until its total consumption. In light of the typical characteristics of the water from protected dug wells and tube wells, this study aimed to evaluate the decay kinetics of free chlorine in the water of alternative individual supply (AIS) solutions used in the city of Porto Velho in the Brazilian Amazon region. The free chlorine decay constant in the water was evaluated by “bottle tests,” applying a first-order model. According to the results, the type of well and initial chlorine concentration significantly influences the free chlorine decay speed. The water samples from the tubular wells had lower chlorine demand levels, attributed to their better water quality. The simulation of the residual chlorine decay in the different supply sources is an important tool to support safe disinfection processes.
Taise Vargas; Célia Baía; Tatiana Machado; Caetano Dórea; Wanderley Bastos. Decay of Free Residual Chlorine in Wells Water of Northern Brazil. Water 2021, 13, 992 .
AMA StyleTaise Vargas, Célia Baía, Tatiana Machado, Caetano Dórea, Wanderley Bastos. Decay of Free Residual Chlorine in Wells Water of Northern Brazil. Water. 2021; 13 (7):992.
Chicago/Turabian StyleTaise Vargas; Célia Baía; Tatiana Machado; Caetano Dórea; Wanderley Bastos. 2021. "Decay of Free Residual Chlorine in Wells Water of Northern Brazil." Water 13, no. 7: 992.
Knowledge gaps exist pertaining to the interaction between anaerobic conditions, microbiology and activity that characterize biodegradation mechanisms in septic tanks.
Kelsey Shaw; Caetano C. Dorea. Biodegradation mechanisms and functional microbiology in conventional septic tanks: a systematic review and meta-analysis. Environmental Science: Water Research & Technology 2020, 7, 144 -155.
AMA StyleKelsey Shaw, Caetano C. Dorea. Biodegradation mechanisms and functional microbiology in conventional septic tanks: a systematic review and meta-analysis. Environmental Science: Water Research & Technology. 2020; 7 (1):144-155.
Chicago/Turabian StyleKelsey Shaw; Caetano C. Dorea. 2020. "Biodegradation mechanisms and functional microbiology in conventional septic tanks: a systematic review and meta-analysis." Environmental Science: Water Research & Technology 7, no. 1: 144-155.
Lack of access to safe drinking water on premises remains widespread in low- and middle-income countries. Interventions to improve access to safe water at the point of collection are essential, but water safety at the point of consumption is also an important consideration. This research aimed to 1) improve understanding of households’ practices in collecting water with respect to seasonality, and 2) to further assess risk associated with post-collection contamination from the point of collection to the point of consumption. A seasonal cohort study, including 115 households, was conducted in Malawi. Along with household surveys and observations, samples of water were tested for microbial water quality at four different stages of water collection: water sources, collection container, storage container, cup of drinking water. Using E.coli as an indicator of contamination (cfu/100 ml), the risk of post-collection contamination was assessed. The results indicate that most water sources were free from contamination; contamination was proportionally lower in the dry season when more sources were found to be classified as having a very low risk of contamination. However, the level of risk of contamination was more likely to increase following collection in water sources that were initially free from contamination. Results show that the degradation in water quality from the point of collection to the point of consumption was more important in the rainy season, which is likely to be driven by the effect of seasonality on the household environment. Filling the collection container at the point of collection and storage at the point of consumption were found to be critical stages for an increased risk of E. coli contamination. Understanding household practices in accessing and handling water during both rainy and dry season is necessary to target appropriate interventions to reduce post-collection contamination.
Alexandra Cassivi; Elizabeth Tilley; E. Owen D. Waygood; Caetano Dorea. Household practices in accessing drinking water and post collection contamination: A seasonal cohort study in Malawi. Water Research 2020, 189, 116607 .
AMA StyleAlexandra Cassivi, Elizabeth Tilley, E. Owen D. Waygood, Caetano Dorea. Household practices in accessing drinking water and post collection contamination: A seasonal cohort study in Malawi. Water Research. 2020; 189 ():116607.
Chicago/Turabian StyleAlexandra Cassivi; Elizabeth Tilley; E. Owen D. Waygood; Caetano Dorea. 2020. "Household practices in accessing drinking water and post collection contamination: A seasonal cohort study in Malawi." Water Research 189, no. : 116607.
Streams and rivers convey freshwater from lands to the oceans, transporting various organic particles, minerals, and living organisms. Microbial communities are key components of freshwater food webs and take up, utilize, and transform this material. However, there are still important gaps in our understanding of the dynamic of these organisms along the river channels. Using high-throughput 16S and 18S rRNA gene sequencing and quantitative PCR on a 11-km long transect of the Saint-Charles River (Quebec, CA), starting from its main source, the Saint-Charles Lake, we show that bacterial and protist community structures in the river drifted quickly but progressively downstream of its source. The dominant Operational Taxonomic Units (OTUs) of the lake, notably related to Cyanobacteria, decreased in proportions, whereas relative proportions of other OTUs, such as a Pseudarcicella OTU, increased along the river course, becoming quickly predominant in the river system. Both prokaryotic and protist communities changed along the river transect, suggesting a strong impact of the shift from a stratified lake ecosystem to a continuously mixed river environment. This might reflect the cumulative effects of the increasing water turbulence, fluctuations of physicochemical conditions, differential predation pressure in the river, especially in the lake outlet by benthic filter feeders, or the relocation of microorganisms, through flocculation, sedimentation, resuspension, or inoculation from the watershed. Our study reveals that the transit of water in a river system can greatly impact both bacterial and micro-eukaryotic community composition, even over a short distance, and, potentially, the transformation of materials in the water column.
Perrine Cruaud; Adrien Vigneron; Caetano C. Dorea; Manuel J. Rodriguez; Steve J. Charette. Rapid Changes in Microbial Community Structures along a Meandering River. Microorganisms 2020, 8, 1631 .
AMA StylePerrine Cruaud, Adrien Vigneron, Caetano C. Dorea, Manuel J. Rodriguez, Steve J. Charette. Rapid Changes in Microbial Community Structures along a Meandering River. Microorganisms. 2020; 8 (11):1631.
Chicago/Turabian StylePerrine Cruaud; Adrien Vigneron; Caetano C. Dorea; Manuel J. Rodriguez; Steve J. Charette. 2020. "Rapid Changes in Microbial Community Structures along a Meandering River." Microorganisms 8, no. 11: 1631.
Billions of people globally gained access to improved drinking water sources and sanitation in the last decades, following effort towards achieving the Millennium Development Goals. Global progress remains a general indicator as it is unclear if access is equitable across groups of the population. Agenda 2030 calling for `leaving no one behind', there is a need to focus on the variations of access in different groups of the population, especially in the context of low- and middle-income countries including Malawi. We analyzed data from Demographic Health Survey (DHS) and Multiple Indicator Cluster Survey (MICS) to describe emerging trends on progress and inequalities in water supply and sanitation services over a 25-year period (1992–2017), as well as to identify the most vulnerable populations in Malawi. Data were disaggregated with geographic and socio-economic characteristics including regions, urban and rural areas, wealth and education level. Analysis of available data revealed progress in access to water and sanitation among all groups of the population. The largest progress was generally observed in the groups that were further behind at the baseline year, which likely reflects good targeting in interventions/improvements to reduce the gap in the population. Overall, results demonstrated that some segments of the population – foremost poorest Southern rural populations – still have limited access to water and are forced to practise open defecation. Finally, we suggest including standardized indicators that address safely managed drinking water and sanitation services in future surveys and studies to increase the accuracy of national estimates.
Alexandra Cassivi; Elizabeth Tilley; E. O. D. Waygood; Caetano Dorea. Trends in access to water and sanitation in Malawi: progress and inequalities (1992–2017). Journal of Water and Health 2020, 18, 785 -797.
AMA StyleAlexandra Cassivi, Elizabeth Tilley, E. O. D. Waygood, Caetano Dorea. Trends in access to water and sanitation in Malawi: progress and inequalities (1992–2017). Journal of Water and Health. 2020; 18 (5):785-797.
Chicago/Turabian StyleAlexandra Cassivi; Elizabeth Tilley; E. O. D. Waygood; Caetano Dorea. 2020. "Trends in access to water and sanitation in Malawi: progress and inequalities (1992–2017)." Journal of Water and Health 18, no. 5: 785-797.
Efforts to control of unwanted disinfection by-products (DBPs) can be hindered by the relatively low-frequency data that is generated from DBP monitoring for regulatory purposes. Differential UV absorbance (DUVA) has the potential to overcome some of these difficulties as a relatively simple and low-cost technique for the estimation of regulated DBPs (i.e., trihalomethanes, THMs, and haloacetic acids, HAAs). DUVA is based on the principle that differences in UV absorbance at specific wavelengths before and after chlorination can be correlated to DBP occurrence. This project sought to assess a lab-based protocol for the determination of a site-specific linear calibration curve for in situ real-time estimations of DBPs from DUVA measurement in water treatment plants (WTPs). A field spectrophotometer probe capable of high frequency scans within the UV light wavelength spectra with light paths of 100 mm was used. Models were developed to estimate DBP levels, at a scale representative of DUVA and DBP levels that actually occur in the WTP under study. Results showed that level of uncertainty on DBP levels estimation is relatively low (23% for HAAs and 32% for THMs). Although DBP estimations through DUVA are not of regulatory value, they can be used for real-time estimation of DBP levels to better inform operational decision making in water treatment plants and management of DBPs in distribution systems.
Guilherme Stéphanie; Dorea Caetano. Real-Time Estimation of Disinfection By-Products through Differential UV Absorbance. Water 2020, 12, 2536 .
AMA StyleGuilherme Stéphanie, Dorea Caetano. Real-Time Estimation of Disinfection By-Products through Differential UV Absorbance. Water. 2020; 12 (9):2536.
Chicago/Turabian StyleGuilherme Stéphanie; Dorea Caetano. 2020. "Real-Time Estimation of Disinfection By-Products through Differential UV Absorbance." Water 12, no. 9: 2536.
In a recent contribution by Curry and colleagues, a field-derived assessment of a reportedly common pretreatment technique to reduce turbidities of biosand filter (BSF) feed water was reported. Their results demonstrated that despite alum pretreatment achieving lower settled turbidity values relative to control filters, such intervention led to significantly lower flow rates in the alum-dosed BSFs. However, their study stopped short of providing a more meaningful interpretation to what may initially seem like a counterintuitive finding, which is presented here.
Caetano C. Dorea. Impact of alum pretreatment on biosand filter performance: a commentary on Curry et al. (2020). Journal of Water, Sanitation and Hygiene for Development 2020, 10, 1034 -1035.
AMA StyleCaetano C. Dorea. Impact of alum pretreatment on biosand filter performance: a commentary on Curry et al. (2020). Journal of Water, Sanitation and Hygiene for Development. 2020; 10 (4):1034-1035.
Chicago/Turabian StyleCaetano C. Dorea. 2020. "Impact of alum pretreatment on biosand filter performance: a commentary on Curry et al. (2020)." Journal of Water, Sanitation and Hygiene for Development 10, no. 4: 1034-1035.
The occurrence and the fate of 18 ozonation by-products (OBPs) (17 different aldehydes and bromate) were studied over one year in two Canadian drinking water systems. This is the first and only study reporting the occurrence of all these non-halogenated aldehydes (NON-HALs) and haloacetaldehydes (HALs) simultaneously, based on the multi-point monitoring of water in full-scale conditions from source to distribution network. In general, the application of both post-ozonation and liquid chlorine contributed to the formation of OBPs (aldehydes and bromate). NON-HALs were present in higher concentrations than HALs. Formaldehyde, acetaldehyde, glyoxal and methylglyoxal were the most common forms of NON-HALs in the two water systems that were studied. Chloral hydrate (CH), the hydrated form of trichloroacetaldehyde, was the most dominant HAL observed. The nature of the organic matter, and the water temperature proved to be important parameters for explaining the variability of aldehydes. Summer and autumn (warm seasons) were more favorable for the formation of chloral hydrate and bromate. The highest concentrations of NON-HALs were observed in spring.
Olivier Laflamme; Jean-B. Sérodes; Sabrina Simard; Christelle Legay; Caetano Dorea; Manuel J. Rodriguez. Occurrence and fate of ozonation disinfection by-products in two Canadian drinking water systems. Chemosphere 2020, 260, 127660 .
AMA StyleOlivier Laflamme, Jean-B. Sérodes, Sabrina Simard, Christelle Legay, Caetano Dorea, Manuel J. Rodriguez. Occurrence and fate of ozonation disinfection by-products in two Canadian drinking water systems. Chemosphere. 2020; 260 ():127660.
Chicago/Turabian StyleOlivier Laflamme; Jean-B. Sérodes; Sabrina Simard; Christelle Legay; Caetano Dorea; Manuel J. Rodriguez. 2020. "Occurrence and fate of ozonation disinfection by-products in two Canadian drinking water systems." Chemosphere 260, no. : 127660.
Safely managed drinking water services (SMDWS) is the service ladder used for the Sustainable Development Goal (SDG) monitoring of drinking water and expands on the Millennium Development Goal metric (“improved water source”) with three additional criteria, namely: availability when needed, accessibility on premises, and safety (free from faecal and priority chemical contamination). Multiple Indicator Cluster Surveys (MICS) have been used for progress monitoring accounting for a significant fraction of the water, sanitation, and hygiene (WASH) indicator data. In its most recent iteration MICS now includes additional SMDWS indicators. The objective of this study was to report on recent SDG target 6.1 baseline data on SMDWS from the Democratic People’s Republic of Korea gathered from a MICS conducted in 2017. Survey results indicated that 93.7% of the population used an improved drinking water source, but when this was combined with the SDG criteria of water availability, accessibility, and safety, coverage was reduced to 92.3, 78.2, and 74.4%, respectively. This resulted in estimates that 60.9% of the population used a SMDWS. The survey results illustrate how the improved SDG indicators can highlight the required gaps to be overcome with regard to universal and equitable access to SMDWS. Further analysis and discussion regarding water quality deterioration between source and household as well as population residence, wealth group index, geographical distribution, and other characteristics relative to SMDWS indicators are also further analysed and discussed.
Caetano C. Dorea; Tatjana Karaulac; Kencho Namgyal; Rob Bain; Tom Slaymaker; Richard Johnston. Safely managed drinking water services in the Democratic People’s Republic of Korea: findings from the 2017 Multiple Indicator Cluster Survey. npj Clean Water 2020, 3, 1 -7.
AMA StyleCaetano C. Dorea, Tatjana Karaulac, Kencho Namgyal, Rob Bain, Tom Slaymaker, Richard Johnston. Safely managed drinking water services in the Democratic People’s Republic of Korea: findings from the 2017 Multiple Indicator Cluster Survey. npj Clean Water. 2020; 3 (1):1-7.
Chicago/Turabian StyleCaetano C. Dorea; Tatjana Karaulac; Kencho Namgyal; Rob Bain; Tom Slaymaker; Richard Johnston. 2020. "Safely managed drinking water services in the Democratic People’s Republic of Korea: findings from the 2017 Multiple Indicator Cluster Survey." npj Clean Water 3, no. 1: 1-7.
Free chlorination is a widely employed disinfection method in humanitarian water provision due to its many advantages. However, its effective application is hindered by the challenge in determining adequate initial doses to achieve free chlorine residuals that satisfy both health and aesthetic requirements. Current guidelines show varying recommended dosing strategies, and many do not adequately consider chlorine decay mechanisms that occur during water storage. Even though turbidity is commonly used as a criterion for deciding chlorine dose, it may not be an adequate proxy for the water quality in many cases. This paper addresses the fundamental relationships between chlorine decay kinetics and selected key water parameters (i.e., natural organic matter, water temperature, chlorine demand) by conducting chlorine decay tests in controlled conditions and in jerrycans (i.e., simulating humanitarian water treatment conditions). Chlorine decay constant from the Feben and Taras’s empirical model and first order model formed linear and exponential relationships with two water parameters (UVA254 and 30-min chlorine demand). With these relationships, the two chlorine decay models can be calibrated quickly and frequently in the field, allowing effective determination of initial chlorine dose. These two models calibrated based on the suggested water parameters from the study could predict chlorine decay in water having a main chlorine demand-inducing constituents as natural organic matter. However, they underpredicted chlorine decay in surface water with additional chlorine reactants. Further research on additional chlorine decay mechanisms is needed to expand the applicability of the models.
Hongjian Wu; Caetano C. C. Dorea. Towards a Predictive Model for Initial Chlorine Dose in Humanitarian Emergencies. Water 2020, 12, 1506 .
AMA StyleHongjian Wu, Caetano C. C. Dorea. Towards a Predictive Model for Initial Chlorine Dose in Humanitarian Emergencies. Water. 2020; 12 (5):1506.
Chicago/Turabian StyleHongjian Wu; Caetano C. C. Dorea. 2020. "Towards a Predictive Model for Initial Chlorine Dose in Humanitarian Emergencies." Water 12, no. 5: 1506.
Billions of people globally gained access to improved drinking water sources and sanitation in the last decades, following effort towards the Millennium Development Goals. Global progress remains a general indicator as it is unclear if access is equitable across groups of the population. Agenda 2030 calling for “leaving no one behind”, there is a need to focus on the variations of access in different groups of the population, especially in the context of least developed countries including Malawi. We analyzed data from Demographic Health Survey (DHS) and Multiple Indicator Cluster Survey (MICS) to describe emerging trends on progress and inequalities in water supply and sanitation services over a 25-year period (1992 - 2017) and to identify the most vulnerable population in Malawi. Data were disaggregated with geographic and socio-economic characteristics including regions, urban and rural areas, wealth and education level. Analysis of available data revealed progress in access to water and sanitation among all groups of the population. The largest progress is generally observed in the groups that were further behind at the baseline year, which likely reflects good targeting in interventions/improvements to reduce the gap in the population. Overall, results demonstrated that some segments of the population - foremost poorest Southern rural populations - still have limited access to water and are forced to practise open defecation. Finally, we suggest to include standardized indicators that address safely managed drinking water and sanitation services in future surveys and studies to increase accuracy of national estimates.
Alexandra Cassivi; Elizabeth Tilley; E.O.D. Waygood; Caetano Dorea. TRENDS IN ACCESS TO WATER AND SANITATION IN MALAWI: PROGRESS AND INEQUALITIES (1992-2017). 2020, 1 .
AMA StyleAlexandra Cassivi, Elizabeth Tilley, E.O.D. Waygood, Caetano Dorea. TRENDS IN ACCESS TO WATER AND SANITATION IN MALAWI: PROGRESS AND INEQUALITIES (1992-2017). . 2020; ():1.
Chicago/Turabian StyleAlexandra Cassivi; Elizabeth Tilley; E.O.D. Waygood; Caetano Dorea. 2020. "TRENDS IN ACCESS TO WATER AND SANITATION IN MALAWI: PROGRESS AND INEQUALITIES (1992-2017)." , no. : 1.
We thank Wassenaar and colleagues for their Comment on our recent paper
Camille Zimmer; Caetano C. Dorea. Reply to Comment on “Enumeration of Escherichia coli in Probiotic Products. Microorganisms 2019, 7, 437”. Microorganisms 2020, 8, 242 .
AMA StyleCamille Zimmer, Caetano C. Dorea. Reply to Comment on “Enumeration of Escherichia coli in Probiotic Products. Microorganisms 2019, 7, 437”. Microorganisms. 2020; 8 (2):242.
Chicago/Turabian StyleCamille Zimmer; Caetano C. Dorea. 2020. "Reply to Comment on “Enumeration of Escherichia coli in Probiotic Products. Microorganisms 2019, 7, 437”." Microorganisms 8, no. 2: 242.
Enhanced coagulation can be an effective way to reduce disinfection by-product (DBP) precursor concentrations. Where turbidity is not extremely high, the natural organic matter concentration evaluated by total or dissolved organic carbon concentration or UV absorbance is known to be the most important factor for determining the adequate coagulant dose. Yet, treatment plant operators are often faced with difficult decisions when it comes to coagulant dosages: Should coagulation efforts and coagulant doses be consistent year-round when water quality changes seasonally? Should the coagulant dose be increased when DBP standards are not met, or has the maximum removal of DBP precursors been reached? The objective and novelty of this study is to revisit the concept of enhanced coagulation and to determine optimal coagulation guidelines based not just on the removal of common indicators such as DOC but on the removal of actual DBP precursors. Jar-tests (for DBP precursor removal evaluation) using alum were conducted under a range of conditions on 8 different natural/synthetic waters with varying physicochemical characteristics for subsequent chlorination over 48 h (for DBP formation potential). A coagulant-dose adjustment strategy based on UV254 monitoring was also implemented at a full-scale facility. Results show that, for the wide range of waters tested, an alum/UV254 stoichiometric dose of 180 ± 25 mg alum cm/L represents a point of diminishing return (i.e. it maximises DBP precursor removal). Another original result of this work is that this dose is applicable and equally efficient in all seasons, despite changes in water quality. For utilities with similar raw waters, this means that coagulation efforts should be proportional to the UV254 of the raw water, regardless of the season.
Nicolas Beauchamp; Christian Bouchard; Caetano Dorea; Manuel Rodriguez. Ultraviolet absorbance monitoring for removal of DBP-precursor in waters with variable quality: Enhanced coagulation revisited. Science of The Total Environment 2020, 717, 137225 .
AMA StyleNicolas Beauchamp, Christian Bouchard, Caetano Dorea, Manuel Rodriguez. Ultraviolet absorbance monitoring for removal of DBP-precursor in waters with variable quality: Enhanced coagulation revisited. Science of The Total Environment. 2020; 717 ():137225.
Chicago/Turabian StyleNicolas Beauchamp; Christian Bouchard; Caetano Dorea; Manuel Rodriguez. 2020. "Ultraviolet absorbance monitoring for removal of DBP-precursor in waters with variable quality: Enhanced coagulation revisited." Science of The Total Environment 717, no. : 137225.
The drying (or dewatering) of fresh feces and fecal sludge is a productive step in the management of sanitation, waste treatment, and resource recovery services. An improved understanding of fresh feces and fecal sludge drying would contribute to the development and deployment of fecal sludge management services. However, there is a lack of available literature on the fundamental drying characteristics of fresh feces. In response to this gap, this work shares experimental results for equilibrium moisture content of fresh feces at different water activity levels (aw) and proposes the use of the Guggenheim, Anderson, and de Boer (GAB) model for predicting aw, calculating the heat of sorption, and estimating the corresponding energy requirements for drying of fresh feces. This is the first time this work has been done with fresh feces. The total heat of evaporation was significant up to a moisture content of about 0.2 kg water per kg dry solids. In addition to informing drying process design, the sorption isotherm can be used to predict microbial activity, which could improve the management of feces and fecal sludge from a public health perspective. These data in turn will be used to promote access to dignified, safe, and sustainable sanitation.
Claire Remington; Catherine Bourgault; Caetano C. Dorea. Measurement and Modelling of Moisture Sorption Isotherm and Heat of Sorption of Fresh Feces. Water 2020, 12, 323 .
AMA StyleClaire Remington, Catherine Bourgault, Caetano C. Dorea. Measurement and Modelling of Moisture Sorption Isotherm and Heat of Sorption of Fresh Feces. Water. 2020; 12 (2):323.
Chicago/Turabian StyleClaire Remington; Catherine Bourgault; Caetano C. Dorea. 2020. "Measurement and Modelling of Moisture Sorption Isotherm and Heat of Sorption of Fresh Feces." Water 12, no. 2: 323.
Young children are particularly vulnerable to the chronic sequelae of anemia, including poor nutritional status. The aim of this study was to assess intestinal parasitic-infections and nutritional status (anemia and linear growth) in preschool children living in contemporary Amazonian communities. A cross-sectional study measured children’s intestinal parasites and hair-Hg (HHg)—biomarkers of fish consumption, hemoglobin levels, and growth (anthropometric Z-scores). Children came from traditional-living families (Itapuã), and tin-mining settlements (Bom Futuro) representing current transitioning populations. It covered 937 pre-school children (from 1 to 59 months of age) from traditional (247) and immigrant tin-mining families (688). There was a high prevalence of intestinal polyparasitic-infection in children from both communities, but mild anemia (hemoglobin concentrations) and moderate (chronic) malnutrition were more frequent in children from traditional families than in children from tin-mining settlers. Children from traditional families ate significantly more fish (HHg mean of 4.3 µg/g) than children from tin-mining families (HHg mean of 2.3 µg/g). Among traditional villagers, children showed a significant correlation (r = 0.2318; p = 0.0005) between hemoglobin concentrations and HHg concentrations. High rates of parasitic infection underlie the poverty and attendant health issues of young children in the Brazilian Amazon. The intestinal parasite burden affecting poor Amazonian children resulting from unsafe water, lack of sanitation and poor hygiene is the most urgent environmental health issue.
Rejane C. Marques; José V. E. Bernardi; Caetano C. Dorea; José G. Dórea. Intestinal Parasites, Anemia and Nutritional Status in Young Children from Transitioning Western Amazon. International Journal of Environmental Research and Public Health 2020, 17, 577 .
AMA StyleRejane C. Marques, José V. E. Bernardi, Caetano C. Dorea, José G. Dórea. Intestinal Parasites, Anemia and Nutritional Status in Young Children from Transitioning Western Amazon. International Journal of Environmental Research and Public Health. 2020; 17 (2):577.
Chicago/Turabian StyleRejane C. Marques; José V. E. Bernardi; Caetano C. Dorea; José G. Dórea. 2020. "Intestinal Parasites, Anemia and Nutritional Status in Young Children from Transitioning Western Amazon." International Journal of Environmental Research and Public Health 17, no. 2: 577.
There is a need for accessible and low-cost microbiological water quality testing in contexts where diarrheal illness is a major public health concern. In most cases, the quantification of Escherichia coli and other microbial indicators by conventional culture methods requires an incubation step for processed samples at specific temperatures for bacterial growth over a prescribed time. However, incubators can be the most expensive equipment required for such microbial analyses, limiting the number and scope of water quality testing available in low-resource contexts. In this study, a low-cost incubator was developed using a locally available expanded polystyrene (EPS) foam cooler, with two water bottles filled with hot water to heat incubator to a target of 35 °C. The EPS incubator performance was validated by processing 150 water samples in duplicates using the Colilert Quanti-tray/2000 system, incubated in either the EPS incubator or a standard laboratory incubator set at 35 °C. Statistically significant correlations of results indicated that the quantification of E. coli was comparable between both methods. Risk categorizations from standard and EPS incubation results agreed for 141 of 150 (94%) samples, with zero false negatives. In addition to being reasonably mobile the EPS incubator would reduce the cost of such water quality testing, thus potentially increasing the scope of water quality testing coverage.
Carolina Bernardes; Ricardo Bernardes; Camille Zimmer; Caetano C. Dorea. A Simple Off-Grid Incubator for Microbiological Water Quality Analysis. Water 2020, 12, 240 .
AMA StyleCarolina Bernardes, Ricardo Bernardes, Camille Zimmer, Caetano C. Dorea. A Simple Off-Grid Incubator for Microbiological Water Quality Analysis. Water. 2020; 12 (1):240.
Chicago/Turabian StyleCarolina Bernardes; Ricardo Bernardes; Camille Zimmer; Caetano C. Dorea. 2020. "A Simple Off-Grid Incubator for Microbiological Water Quality Analysis." Water 12, no. 1: 240.
Probiotic products typically take the form of oral supplements or food-based products containing microorganisms, typically bacteria. The number of bacteria present in a dose of probiotic can be several orders of magnitude lower than the label claims, and in some cases, undetectable. The objective of this study was to assess probiotic products containing Escherichia coli to verify manufacturer claims, which have not yet been independently assessed, regarding the number of viable E. coli per suggested dose. It was found that the products tested contained E. coli in numbers several orders of magnitude less than claimed, and when subjected to simulated stomach conditions, the number of viable E. coli was significantly reduced.
Camille Zimmer; Caetano Dorea. Enumeration of Escherichia coli in Probiotic Products. Microorganisms 2019, 7, 437 .
AMA StyleCamille Zimmer, Caetano Dorea. Enumeration of Escherichia coli in Probiotic Products. Microorganisms. 2019; 7 (10):437.
Chicago/Turabian StyleCamille Zimmer; Caetano Dorea. 2019. "Enumeration of Escherichia coli in Probiotic Products." Microorganisms 7, no. 10: 437.
In a recent article an assessment of decomposition within pit latrines measured with regard to chemical oxygen demand (COD) reductions was reported on. Some fundamental concerns were raised with regard to a key assumption of the study. The alternative perspective that is presented here does not support the study's conclusion that anaerobic processes are the dominant decomposition pathway in pit latrines. Furthermore, it is argued that their analysis and some implications of their data interpretation can be viewed in a different manner.
Catherine Bourgault; Kelsey Shaw; Caetano C. Dorea. Dominant decomposition pathways in pit latrines: a commentary. Water Science and Technology 2019, 80, 1392 -1394.
AMA StyleCatherine Bourgault, Kelsey Shaw, Caetano C. Dorea. Dominant decomposition pathways in pit latrines: a commentary. Water Science and Technology. 2019; 80 (7):1392-1394.
Chicago/Turabian StyleCatherine Bourgault; Kelsey Shaw; Caetano C. Dorea. 2019. "Dominant decomposition pathways in pit latrines: a commentary." Water Science and Technology 80, no. 7: 1392-1394.