Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 203
Filtrar
2.
An Acad Bras Cienc ; 91(3): e20171022, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31576911

RESUMO

Field surveys and integral modelling were carried out to study the effect of bubble plumes on the flow hydrodynamics and the time-evolution of water temperature profiles in a shallow lake with maximum depth of about 4 m. Then, model simulations were performed to verify the feasibility of destratification of ten water-supply reservoirs with capacities of 10-2,000 hm3. Finally, hydrological modelling was conducted to assess the impact of destratification on evaporation suppression and its effects on reservoir yield. The results indicate that net temperature reductions of the order of 1.0°C can be obtained, which corresponds to evaporation suppressions of approximately 10%. In turn, this resulted in increases in the regulated flow of 2-12% that could be described by a general correlation. Lastly, a simplified feasibility analysis provided an operational cost of about 1.0 US$ per cubic meter of saved water, which suggests that artificial destratification cannot be discarded as an alternative for supplementing water supply in rural water-scarce regions.


Assuntos
Lagos , Temperatura Ambiente , Recursos Hídricos , Abastecimento de Água/métodos , Brasil , Hidrodinâmica , Estações do Ano , Fatores de Tempo
3.
Nature ; 574(7776): 90-94, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31578485

RESUMO

Groundwater is the world's largest freshwater resource and is critically important for irrigation, and hence for global food security1-3. Already, unsustainable groundwater pumping exceeds recharge from precipitation and rivers4, leading to substantial drops in the levels of groundwater and losses of groundwater from its storage, especially in intensively irrigated regions5-7. When groundwater levels drop, discharges from groundwater to streams decline, reverse in direction or even stop completely, thereby decreasing streamflow, with potentially devastating effects on aquatic ecosystems. Here we link declines in the levels of groundwater that result from groundwater pumping to decreases in streamflow globally, and estimate where and when environmentally critical streamflows-which are required to maintain healthy ecosystems-will no longer be sustained. We estimate that, by 2050, environmental flow limits will be reached for approximately 42 to 79 per cent of the watersheds in which there is groundwater pumping worldwide, and that this will generally occur before substantial losses in groundwater storage are experienced. Only a small decline in groundwater level is needed to affect streamflow, making our estimates uncertain for streams near a transition to reversed groundwater discharge. However, for many areas, groundwater pumping rates are high and environmental flow limits are known to be severely exceeded. Compared to surface-water use, the effects of groundwater pumping are markedly delayed. Our results thus reveal the current and future environmental legacy of groundwater use.


Assuntos
Mapeamento Geográfico , Água Subterrânea/análise , Chuva , Rios/química , Movimentos da Água , Abastecimento de Água/métodos , Irrigação Agrícola/métodos , Organismos Aquáticos , Mudança Climática , Dessecação , Secas/estatística & dados numéricos , Ecossistema , Água Doce/análise , Internacionalidade , Modelos Teóricos
4.
J Appl Microbiol ; 127(6): 1889-1900, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31489745

RESUMO

AIMS: Effect of ground water (GW), secondary-treated wastewater (STWW) and roof-harvested rainwater (RHW) irrigation on microbiological quality of spinach in field was investigated. METHODS AND RESULTS: Spinach grown at the Fulton farm (Chambersburg, PA) was spray-irrigated with GW, STWW or RHW once a week for 2 weeks in summer and fall seasons. Four replicate spinach and soil samples collected from two plots for each group were analysed for indicator and pathogenic bacteria on 0, 1, 2 and 4 days postirrigation (dpi). While total coliforms remained unchanged on spinach regardless of the treatment waters and growing seasons, populations of faecal coliform significantly decreased on RHW- and STWW-irrigated spinach as compared to spinach irrigated with GW at 4 dpi of each week in fall. Irrigation with STWW that contained Escherichia coli population <1·0 log CFU per 100 ml resulted in the lowest E. coli recovery on spinach in fall. Bacterial pathogens were not detected in any sample. CONCLUSIONS: The transference of indicator micro-organisms from irrigation waters to plants was influenced by the type of water and growing season. SIGNIFICANCE AND IMPACT OF THE STUDY: Alternative water sources such as STWW and RHW containing low indicator bacterial populations may be suitable for spinach irrigation in the mid-Atlantic region. However, microbiological quality of these waters must be determined prior to their use for irrigation.


Assuntos
Irrigação Agrícola/métodos , Escherichia coli/isolamento & purificação , Microbiologia de Alimentos , Spinacia oleracea/microbiologia , Microbiologia da Água , Abastecimento de Água/métodos , Contagem de Colônia Microbiana , Escherichia coli/classificação , Fezes/microbiologia
5.
Chemosphere ; 236: 124329, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31310967

RESUMO

Plastic pipes have been and are being installed downstream of metal drinking water plumbing components. Prior research has suggested that such pipe configurations may induce plastic pipe degradation and even system failure. To explore the impact of upstream metal plumbing components on downstream plastic pipes, field- and bench-scale experiments were conducted. Six month old galvanized iron pipes (GIPs) and downstream crosslinked polyethylene (PEX) pipes were exhumed from a residential home. Calcium, iron, manganese, phosphorous, and zinc were the most abundant elements on both GIPs and PEX pipes. Black and yellow deposits were found on some of the exhumed PEX pipe inner walls, which were mainly copper, iron, and manganese oxides (CuO, Cu(OH)2, Fe2O3, FeOOH and MnO2). Follow-up bench-scale experiments revealed that metal levels in the drinking water did not always predict metal loadings on plastic pipe surfaces. The pH 4 water resulted in a greater amount of metals released into the bulk water, but the pH 7.5 water resulted in a greater amount of metals deposited on the PEX pipe surfaces. Hot water (55 °C) induced a greater amount of organics released and higher metal loadings on PEX pipe surfaces at pH 7.5. ATR-FTIR analysis showed that at 55 °C, PEX pipes connected to copper and brass components had the greatest oxidation functional group peak intensity (COOC, CO, and COC). This study highlights potential downstream plastic pipe degradation and metal deposition, which may cause plumbing problems and failures for building owners, inhabitants, and water utilities.


Assuntos
Água Potável/química , Metais/química , Engenharia Sanitária/métodos , Corrosão , Abastecimento de Água/métodos
6.
Chemosphere ; 232: 403-414, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31158635

RESUMO

The Three Gorges Reservoir (TGR) of China, the largest hydropower project over the world, has attracted much attention to the water impoundment and water-level manipulation. In this study, we evaluated potential effects of water impoundment and seasonal water-level manipulation on the bioaccumulation, trophic transfer and health risk of HMs (Cu, Fe, Zn, Hg, Cd and Pb) in food web components (seston, aquatic invertebrate and fish) in TGR. Our results show that, after the impoundment for eight years (2003-2010), all of the six metal concentrations in aquatic biota fell within the criteria of safety quality guidelines. The concentrations of Cu, Fe, Zn and Hg in fish and aquatic invertebrates were higher than those before impoundment, whereas Cd and Pb were lower than those before impoundment. Nonetheless, Hg, Cd and Pb in aquatic consumers underwent an increasing trend during the entire impoundment, implying potential reservoir effect in the future. Only the concentrations of Hg, Cd and Pb in aquatic consumers exhibited a declining trend towards the dam, showing consistent with the background level at the three reaches. Seasonal variations in HM concentrations of fish and aquatic invertebrates were ascribed to the water-level manipulation associated with reservoir management. Our findings show that Hg or Cd biomagnified through aquatic food web during different hydrological periods, whereas Pb, Cu, Fe and Zn exhibited weak biomagnification power. Overall, Hg, Cd and Pb showed a higher risk than that of Cu, Fe and Zn.


Assuntos
Organismos Aquáticos/metabolismo , Monitoramento Ambiental/métodos , Metais Pesados/análise , Poluentes Químicos da Água/análise , Abastecimento de Água/métodos , Animais , China , Peixes/metabolismo , Cadeia Alimentar , Invertebrados/química
7.
Philos Trans A Math Phys Eng Sci ; 377(2150): 20190119, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31177952

RESUMO

Fresh water sustains human life and is vital for human health. Water scarcity affects more than 40% of the global population and is projected to rise. For some of the poorest countries, 1 in 10 people do not have access to safe and easily accessible water sources. Water consumption by man continues to grow with increasing population. Furthermore, population growth and unsafe industrial practices, as well as climate change, have put strain on 'clean' water supply in many parts of the world, including the Americas. Current supply of fresh water needs to be supplemented to meet future needs. Living nature provides many lessons for water source. It has evolved species, which can survive in the most arid regions of the world by water collection from fog and condensation in the night. Before the collected water evaporates, species have mechanisms to transport water for storage or consumption. These species possess unique chemistry and structures on or within the body for collection and transport of water. In this paper, an overview of arid desert conditions and water collection from fog, and lessons from living nature for water collection are provided. Data on various bioinspired surfaces for water collection are also presented. Some bioinspired water purification approaches are presented. Next, consumer to military and emergency applications are discussed and water collection projections are presented. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 2)'.


Assuntos
Materiais Biomiméticos , Abastecimento de Água , Água , Tempo (Meteorologia) , Água/química , Abastecimento de Água/métodos
8.
Philos Trans A Math Phys Eng Sci ; 377(2150): 20190118, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31177953

RESUMO

Cacti use the Laplace pressure gradient due to conical geometry as a mechanism for collecting water from fog. Bioinspired surfaces using conical geometry can be developed for water collection from fog for human consumption. A systematic study is presented which investigates the dynamics of water droplets on a bioinspired conical surface. A series of experiments was conducted where a known volume of droplets was deposited on the cone. This was followed by an investigation into droplet dynamics where the droplets are deposited from fog and the volume is unknown. This includes a study on the macroscopic level as well as the microscopic level. The main parameters that were varied for these tests were the tip angle and the cone orientation. The droplet movement observed was compared relatively. Based on captured videos of droplet movement, distance travelled and velocities were measured. The Laplace pressure gradient, gravity and droplet coalescence were found to be the mechanisms of droplet movement on a conical surface. The findings of this study should be of interest in designing bioinspired surfaces with high water collection. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 2)'.


Assuntos
Biomimética , Água Potável , Propriedades de Superfície , Abastecimento de Água , Água , Tempo (Meteorologia) , Cactaceae/anatomia & histologia , Água/química , Abastecimento de Água/métodos , Molhabilidade
9.
Sci Total Environ ; 679: 1-11, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31078770

RESUMO

Taste and odor (T & O) issues in drinking water have become serious problems which cannot be ignored by customers. Several studies have confirmed that microbes in water can biotransform halophenols (HPs) to haloanisoles (HAs) with earthy and musty flavors via microbial O-methylation. In this paper, the formation of 2-chloroanisole (2-CA), 2,4-dichloroanisole (2,4-DCA), 2,4,6-trichloroanisole (2,4,6-TCA), 2,3,6-trichloroanisole (2,3,6-TCA) and 2,4,6-tribromoanisole (2,4,6-TBA), and the microbial variation during the microbial O-methylation were investigated in annular reactors (ARs) with three coupon materials. For precursors, 42.5% of 2-CP and 68.9% of 2,4-DCP decayed during the reaction. Among the five HAs, the formation rate constant followed an order of 2,4,6-TCA > 2-CA > 2,4,6-TBA > 2,4-DCA ~ 2,3,6-TCA, while [HA]max followed a totally opposite one. The simulated flow velocity had no significant effect (p > 0.05) on HA formation. Ductile iron (DI) AR could produce more HAs than stainless steel (SS) and polyvinyl chloride (PVC) ARs. The final HA molar concentration followed an order of 2,3,6-TCA > 2,4-DCA > 2,4,6-TBA ~ 2,4,6-TCA > 2-CA, which might be explained by multiple factors including HP's dissociation degree, halogen atom's steric hindrance and specificity of HP O-methyltransferases. During the reaction, the microbial biomass dramatically increased 6.8-9.0 times in bulk water but dropped significantly on coupon biofilms. The effect of HPs significantly changed the bacterial communities on coupon in terms of composition and diversity, and declined the relative abundance of HA-producing bacteria, while fungi and their HA-producing genus showed better resistance ability towards HPs. By using Pearson correlation analysis, a significant correlation (p = 0.0003) was found between [HA]max and initial coupon biofilm biomass. Finally, a linear relationship was established between initial total biomass and HA formation potential.


Assuntos
Anisóis/metabolismo , Biofilmes , Biomassa , Água Potável/microbiologia , Consórcios Microbianos/fisiologia , Abastecimento de Água/métodos , Reatores Biológicos , Água Potável/química , Metilação , Resistência ao Cisalhamento
10.
Environ Sci Pollut Res Int ; 26(19): 19991-19996, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31089993

RESUMO

Desalination is an important strategy for adapting to the global shortage in safe drinking water. Israel relies heavily on desalinated water (over 50% of supplied drinking water). However, desalinated water may be more corrosive than water from other sources and may cause leaching of heavy metals from materials in contact with water. In this study, we measured heavy metal concentrations (copper, iron, lead) in 1379 drinking water samples in educational institutions in Israel and compared heavy metal concentrations in drinking water from different sources (desalination, groundwater, desalinated and groundwater mixture). 99.9% of the samples met the standard for copper (1400 µg/l), 99.7% for iron (1000 µg/l), and 99.6% for lead (10 µg/l). As expected, heavy metal concentrations were higher in first flush samples compared to flushed samples (significant findings for lead, copper, and iron). Heavy metal concentrations were not higher in desalinated water, or desalinated and groundwater mixture, compared to groundwater. In first flush samples, lead concentrations in groundwater were significantly higher than in desalinated-groundwater mixtures (p = 0.005). In flushed samples, lead concentrations in groundwater were higher than in desalinated-groundwater mixtures but the difference was not significant (p = 0.07). We suggest that regulatory requirements for stabilization of desalinated water and restrictions on lead content of plumbing materials appear to have been effective in preventing increased exposure to lead in desalinated drinking water in Israel. Further study should focus on potential heavy metal leaching in pure desalinated water samples.


Assuntos
Água Potável/análise , Água Subterrânea/análise , Metais Pesados/análise , Poluentes Químicos da Água/análise , Abastecimento de Água/métodos , Cobre/análise , Ferro/análise , Israel , Chumbo/análise
11.
Sci Total Environ ; 683: 537-546, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31146059

RESUMO

Achieving equitable access to water, sanitation and hygiene (WASH) services requires paying special attention to the most disadvantaged segments of the population. Yet, despite all the progress made to evaluate the access of vulnerable and marginalized groups, important knowledge gaps still remain with respect to identifying their specific barriers and needs. At the global level, for example, the two monitoring mechanisms for SDG 6 - the Joint Monitoring Programme (JMP) and Global Analysis and Assessment of Sanitation and drinking-water (GLAAS) - face difficulties in understanding how, and to what extent, vulnerable and marginalized groups access WASH services. In this context, this work examines the UNECE/WHO-Europe 'Equitable Access Score-card' for assessing the access to WASH services by vulnerable and marginalized groups. In particular, we: (i) analyse its strengths and limitations as a tool for revealing the needs of these groups in accessing WASH services; and (ii) propose an extended variant of the score-card that addresses these limitations. We test this version in two local-level case studies: Lima (Peru) and Castelló de la Plana (Spain). The score-card diagnosis is found to be particularly useful for collecting information on the level of access of the different vulnerable and marginalized groups, as well as the specific public policies and funding mechanisms in place that address and support their needs. However, the score-card should be complemented with specific assessments of all five normative dimensions of the human rights to water and sanitation (access, availability, quality, acceptability and affordability) in order to have a better understanding of the concerns for service delivery for the different vulnerable and marginalized groups.


Assuntos
Água Potável , Higiene , Saneamento , Recursos Hídricos/provisão & distribução , Abastecimento de Água/métodos , Direitos Humanos , Humanos , Pobreza , Fatores Socioeconômicos , Abastecimento de Água/economia , Abastecimento de Água/estatística & dados numéricos
12.
BMC Public Health ; 19(1): 392, 2019 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-30971223

RESUMO

BACKGROUND: In 2014, a study in Munyenge revealed a high prevalence of urogenital schistosomiasis (UGS) among pregnant women. This study investigated he prevalence and risk factors of UGS in pregnancy following scale-up of piped water sources from 2014 to 2017. Secondly, we compared stream usage, stream contact behaviour, infection rate and intensity with the findings of 2014. METHODS: Consenting pregnant women reporting for antenatal care (ANC) in the different health facilities were enrolled consecutively between November 2016 and January 2018. Information on age, gravidity status, residence, marital status, educational level, occupation, household water source, frequency of contact with water and stream activities were obtained using a semi-structured questionnaire. Urine samples were examined for the presence of microhaematuria and S. haematobium ova using test strip and filtration/microscopy methods respectively. Data were analysed using univariate and multivariate regression analyses and relative risk reductions calculated. RESULTS: Of the 368 women enrolled, 22.3% (82) were diagnosed with UGS. Marital status (single) (aOR = 2.24, 95% CI: 1.04-4.79), primary - level of education (aOR = 2.0; 95% CI: 1.04-3.85) and domestic activity and bathing in the stream (aOR = 3.3; 95% CI: 1.83-6.01) increased risk of S. haematobium infection. Meanwhile, fewer visits (< 3 visits/week) to stream (aOR = 0.35, 95% CI = 0.17-0.74) reduced exposure to infection. Piped water usage was associated with reduced stream usage and eliminated the risk of infection among women who used safe water only. Compared with the findings of 2014, stream usage (RRR = 23 95% CI: 19-28), frequency (≥ 3 visits) (RRR = 69 95% CI: 59-77) and intensity of contact with water (RRR = 37 95% CI = 22-49) has reduced. Similarly, we observed a decrease in infection rate (RRR = 52, 95% CI = 40-62) and prevalence of heavy egg intensity (RRR = 71, 95% CI = 53-81). CONCLUSION: Following increased piped water sources in Munyenge, S. haematobium infection has declined due to reduced stream contact. This has important implication in the control of UGS in pregnancy.


Assuntos
Complicações Parasitárias na Gravidez/epidemiologia , Schistosoma haematobium , Esquistossomose Urinária/epidemiologia , Abastecimento de Água/métodos , Água/parasitologia , Adolescente , Adulto , Animais , Camarões/epidemiologia , Estudos Transversais , Feminino , Filtração , Hematúria/epidemiologia , Hematúria/parasitologia , Humanos , Microscopia , Gravidez , Complicações Parasitárias na Gravidez/etiologia , Complicações Parasitárias na Gravidez/parasitologia , Cuidado Pré-Natal , Prevalência , Fatores de Risco , Rios/parasitologia , Esquistossomose Urinária/etiologia , Esquistossomose Urinária/parasitologia , Inquéritos e Questionários , Adulto Jovem
13.
J Environ Sci (China) ; 81: 52-67, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30975330

RESUMO

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.


Assuntos
Desinfetantes/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , China , Desinfecção/estatística & dados numéricos , Purificação da Água/estatística & dados numéricos , Abastecimento de Água/métodos , Abastecimento de Água/estatística & dados numéricos
14.
Am J Trop Med Hyg ; 100(4): 981-987, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30834882

RESUMO

The PackH2O water backpack carrier was developed to provide safe storage and relieve stress of head-loading during water transport with traditional containers such as buckets and jerry cans. We conducted an evaluation to assess both self-reported and observed use over a 6-month period between November 2014 and May 2015. A total of 866 packs were distributed to 618 households in six communities in rural Haiti, and 431 and 441 households were surveyed at midline and end line, respectively. We performed linear regression to assess change of self-reported use over time. Although 79.3% of respondents reported continued use of the 20-L pack after 6 months, other measures of self-reported use were low, with only 16.8% reporting to have used the pack the last time they collected water and 10.3% preferring the pack over other water collection containers. In addition, only 10.2% of all people collecting water at community sources were observed using packs and 12.0% of all households surveyed had water in the pack at the time of visit. Pack use varied by community and demographics. Although women were targeted during distribution, men preferred the pack and were more commonly observed using it at the community water sources. In conclusion, the use of the PackH2O was not widely adopted in rural Haiti; however, further research is needed to assess the pack acceptance in areas where back-loading is more common and in emergency settings.


Assuntos
Água Potável , Transportes/instrumentação , Abastecimento de Água/métodos , Características da Família , Feminino , Haiti , Humanos , Modelos Lineares , Masculino , População Rural , Autorrelato , Inquéritos e Questionários
15.
Asia Pac J Clin Nutr ; 28(Suppl 1): S17-S31, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30729772

RESUMO

BACKGROUND AND OBJECTIVES: Intrauterine growth retardation (IUGR) is related to mortality and morbidity. However, defining IUGR by suitable field methods remains a challenge. A maternal-child Risk-Approach- Strategy (during 1988-1989) and follow-on Tanjungsari Cohort Study (TCS) (1989-1990), aimed to generate a practical classification of IUGR and explore its usage in predicting growth, mortality and morbidity of infants in the cohort. STUDY DESIGN: Some 3892 singleton live-birth infants were followed. IUGR was defined by birth weight (BW) and length (BL) classified as: acute, chronic, non-IUGR or 'probably preterm'. Growth, mortality, and survival curve were calculated to prove that the classification identified the most vulnerable infants. Fever >3 days and diarrhoea were assessed based on IUGR classification, sex, exclusive breastfeeding, and environmental factors. RESULTS: IUGR infant weight and length did not catch-up with the non-IUGR in the first year. Infant mortality rate was 44.7 per 1000 where some 61% died within 90 days. Using age specific mortality by BW, 23.6% of all deaths occurred when it was <2500 g compared to 66.2% from IUGR and preterm groups. Fever and diarrhoea rates increased over 12 months. Diarrhoea was associated with poor source-of-drinking-water and latrine. CONCLUSION: The IUGR classification predicted one-year growth curves and survival, besides age and sex. IUGR based on BW and BL identified a larger group of at-risk infants than did low BW. High morbidity rates were partly explained by poor environmental conditions. IUGR inclusive of BL has value in optimizing nutritional status in the first 1000 days of life.


Assuntos
Retardo do Crescimento Fetal/mortalidade , Mortalidade Infantil , Adulto , Fatores Etários , Peso ao Nascer , Estatura , Aleitamento Materno , Causas de Morte , Estudos de Coortes , Diarreia/epidemiologia , Escolaridade , Feminino , Retardo do Crescimento Fetal/classificação , Febre/epidemiologia , Cabeça/anatomia & histologia , Humanos , Indonésia/epidemiologia , Lactente , Recém-Nascido , Entrevistas como Assunto , Masculino , Morbidade , Gravidez , Fatores de Risco , Fatores Sexuais , Toaletes/normas , Abastecimento de Água/métodos , Adulto Jovem
17.
Artigo em Inglês | MEDLINE | ID: mdl-30795730

RESUMO

The water distribution network is largely affected by the change in the influencing factors, such as input pressure, demand and supply duration. The change in each parameter requires the extensive design of the network and the interactive effect of the influencing parameters are hardly explored. The main hurdles for the water providers lie in the absence of a prediction model, which can be used as a decision tool to assess the effect of the change in parameter and estimating the cost for the changed scenario. The present study developed a novel framework based on the artificial neural network for multivariate prediction modeling taking the response as the cost of the pipe network. The application of the 33 factorial design was used for the selection of the influencing parameters and outcome was taken as the input to the neural network model. The adequacy of the model was tested through error functions and analysis of variance. The low values of the error functions (0.0004-0.228) and high F value (162,442) and R2 (0.999) established the significance of the model. The model can be used for predicting the cost of the changed scenarios and assessment of the optimal solution for the system variables.


Assuntos
Modelos Teóricos , Projetos de Pesquisa , Abastecimento de Água/métodos , Algoritmos , Abastecimento de Água/economia
18.
Environ Sci Pollut Res Int ; 26(6): 5794-5803, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30613893

RESUMO

This study investigated the characteristics of iron corrosion scales in pipes at tube well, overhead tank, and consumers' end in older untreated water distribution system in Peshawar city, Pakistan. Effect of water quality conditions on corrosion scales and that of scales on drinking water quality in such systems was also assessed by undertaking a comparison with new piped distribution systems. The scales were analyzed for chemical composition and morphology using X-ray diffraction (XRD), inductively coupled plasma (ICP), and a scanning electron microscope (SEM), while water quality was examined for physicochemical and biological characteristics. The main crystalline phases of corrosion scales were goethite, magnetite, siderite, and quartz. From tube well to consumers' end, goethite increased from 36 up to 48%, quartz declined from 22 to 15%, while magnetite fluctuated and siderite disappeared. Elemental composition of scales showed the deposition of Zn, Al, Mn, Cr, Pb, Cu, As, and Cd with Zn (13.9 g/kg) and Al (3.6 g/kg) in highest proportion. The SEM analysis illustrated the presence of microbial communities indicating the formation of biofilms in the corrosion scales. The significant difference (P < 0.05) in levels of dissolved oxygen (DO), Cl-, SiO44-, electrical conductivity (EC), SO42-, NO3-, alkalinity, hardness, and trace metals between old (DS-O) and new piped systems indicated their role in corrosion scale formation/destabilization and the effect of scale dissolution on water quality. In DS-O, EC, Cu, and Mn were significantly higher (P < 0.05), whereas turbidity, EC, DO, and SiO44- significantly increased from source to consumers' end implying a higher dissolution of scales and lowered corrosion rates in DS-O to utilize SiO44- and DO for iron oxidation.


Assuntos
Água Potável/química , Poluentes Químicos da Água/análise , Abastecimento de Água/métodos , Carbonatos , Corrosão , Compostos Férricos , Óxido Ferroso-Férrico , Ferro , Compostos de Ferro , Minerais , Paquistão , Água , Qualidade da Água , Abastecimento de Água/estatística & dados numéricos , Difração de Raios X
19.
Environ Monit Assess ; 191(2): 80, 2019 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-30656497

RESUMO

Rainwater is a typical source of drinking water in the coastal areas of Bangladesh given the acute scarcity of drinking water. This study assessed potability of harvested rainwater of primary schools in southwest coastal Bangladesh. Water samples collected from 23 primary schools of Mongla sub-district under Bagerhat district were evaluated for indicator bacteria (total coliform (TC) and E. coli) and physico-chemical parameters (pH, electrical conductivity, turbidity, total dissolved solid, Fe, Zn, Pb, and Cd). Median concentrations of TC and E. coli in the harvested rainwater samples were respectively 3000 cfu/100 ml and 6 cfu/100 ml. However, concentrations of these indicator bacteria were lower at the consumption points which received a prior treatment. Concentration of Pb exceeded the maximum allowable limit for drinking water indicated by WHO and Bangladesh drinking water guideline value in 92% and 61% of the samples respectively, and the mean concentration was 0.08 mg/l (8 times higher than the WHO guideline value). The Pb contamination possibly occurred from the painting on roof railing and roof stair room. Therefore, consumption of harvested rainwater at primary schools may cause substantial health risk for the school-going children.


Assuntos
Água Potável/química , Água Potável/microbiologia , Chuva/química , Chuva/microbiologia , Qualidade da Água , Abastecimento de Água/métodos , Bangladesh , Criança , Pré-Escolar , Monitoramento Ambiental , Escherichia coli/isolamento & purificação , Humanos , Chumbo/análise , Instituições Acadêmicas
20.
Sci Total Environ ; 651(Pt 2): 2913-2926, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30463143

RESUMO

The San Antonio Region is home to a rapidly growing population with developing energy and agricultural sectors competing for water, land, and financial resources. Despite the tight interconnectedness between water, energy, and food challenges, little is known about the levels of communication and coordination among the various officials responsible for making the decisions that affect the management and planning of the three resource systems. It has been postulated that efficient communication is a prerequisite to developing resource allocation strategies that avoid potential unintended negative consequences that could result from inefficient allocation of natural resources and competing demands. Factors that may impact communication are identified and their potential roles are considered in improving existing levels of communication between San Antonio's water officials and those at other energy, food, and water institutions in the San Antonio Region. A questionnaire designed to gather information on stakeholder concerns, frequency of communication, and participation in engagement forums was sent to public water officials in the Region. Using social network analysis and bivariate Ordinary Least Square regression analysis, the authors conclude that while modest levels of communication exist among water institutions, a very low level of communication exists between water institutions and those responsible for food and energy. It was further concluded that the frequency of communication among officials at different water institutions is higher among those that participated in stakeholder engagement activities. However, there is insufficient evidence to suggest that participation in stakeholder engagement activities improves communication frequency between water stakeholders and those in the food and energy sectors. There is also insufficient evidence to conclude that people at water institutions in San Antonio would have a higher frequency of communication with other water, energy, and food stakeholder in correlation with a higher level of concern about future water availability in the Region.


Assuntos
Conservação dos Recursos Naturais/métodos , Abastecimento de Alimentos/métodos , Abastecimento de Água/métodos , Agricultura , Humanos , Texas , Água
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA