RESUMEN
The most important requirements for achieving effective separation conditions in inclined plate settler (IPS) are its hydraulic performance and the equal distribution of suspensions between settler channels, both of which depend on the inlet configuration. In this study, three different inlet structures were used to explore the effect of feeding a bench scale IPS via a nozzle distributor on its hydraulic performance and separation efficiency. Experimental and Computational Fluid Dynamic (CFD) analyses were carried out to evaluate the hydraulic characteristics of the IPS. Comparing the experimental results with the predicted results by CFD simulation implies that the CFD software can play a useful role in studying the hydraulic performance of the IPS by employing residence time distribution (RTD) curves. The results also show that the use of a nozzle distributor can significantly enhance the hydraulic performance of the IPS, which contributes to the improvement of its separation efficiency.
Asunto(s)
Eliminación de Residuos Líquidos/instrumentación , Contaminantes Químicos del Agua/química , Simulación por Computador , Hidrodinámica , Suspensiones , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/análisisRESUMEN
OBJECTIVE: Investigate differences in the infectious aetiology, health seeking behaviour, and provider practices with regard to diarrhoeal illness among children presenting to urban versus rural clinics in Western Kenya. DESIGN: Laboratory-based, passive surveillance. SETTING: The urban portion of the study was conducted at the paediatric outpatient clinic of Nyanza Provincial Hospital in Kisumu. The rural portion of the study was conducted at four outpatient clinics in the Asembo Bay community approximately 20 kilometers west of Kisumu. SUBJECTS: Children aged less than five years presenting to medical facilities for the treatment of diarrhoea from October 2001-October 2003 at the urban site and May 1997-April 2003 for the rural sites. RESULTS: Among the 1303 urban and 1247 rural specimens collected, 24% of specimens yielded a bacterial pathogen (24% urban, 25% rural). Campylobacter was the predominant bacterial pathogen (17% urban, 15% rural), followed by Shigella and nontyphoidal Salmonella (both 4% urban and 5% rural). In both communities, susceptibilities of these pathogens to the most commonly prescribed antibiotics was low (< or = 50%); 70% of all episodes of diarrhoea were prescribed antibiotic treatment. Urban health practitioners prescribed fewer antibiotics, chose drugs more likely to be effective, and were more likely to prescribe oral rehydration therapy for bloody diarrhoea. CONCLUSION: Most characteristics of diarrhoeal disease and their causes were similar in paediatric patients presenting to urban and rural clinics. Urban providers were more compliant with WHO recommendations.
Asunto(s)
Infecciones Bacterianas/microbiología , Diarrea/microbiología , Bacterias Gramnegativas/aislamiento & purificación , Infecciones por Bacterias Gramnegativas/epidemiología , Aceptación de la Atención de Salud/estadística & datos numéricos , Distribución por Edad , Antibacterianos/uso terapéutico , Infecciones Bacterianas/epidemiología , Preescolar , Diarrea/epidemiología , Diarrea/etiología , Diarrea/terapia , Farmacorresistencia Microbiana , Heces/microbiología , Femenino , Fluidoterapia , Bacterias Gramnegativas/clasificación , Bacterias Gramnegativas/efectos de los fármacos , Infecciones por Bacterias Gramnegativas/microbiología , Adhesión a Directriz , Humanos , Lactante , Kenia/epidemiología , Masculino , Vigilancia de la Población , Pautas de la Práctica en Medicina/estadística & datos numéricos , Población Rural , Resultado del Tratamiento , Población UrbanaRESUMEN
AIMS: Point-of-use drinking water disinfection with sodium hypochlorite has been shown to improve water quality and reduce diarrhoeal disease. However, the chlorine demand of highly turbid water may render sodium hypochlorite less effective. METHODS AND RESULTS: We evaluated a novel combined flocculant-disinfectant point-of-use water treatment product and compared its effect on drinking water quality with existing technologies in western Kenya. In water from 30 sources, combined flocculant-disinfectant reduced Escherichia coli concentrations to <1 CFU100 ml(-1) for 29 (97%) and reduced turbidity to <5 nephelometric turbidity units (NTU) for 26 (87%). By contrast, water from 30 sources treated with sodium hypochlorite reduced E. coli concentrations to <1 CFU 100 ml(-1) for 25 (83%) and turbidity to <5 NTU for 5 (17%). CONCLUSIONS: For source waters over a range of turbidities in western Kenya, combined flocculant-disinfectant product effectively reduces turbidity to <5 NTU and reduces E. coli concentrations to <1 CFU 100 ml(-1). SIGNIFICANCE AND IMPACT OF THE STUDY: The novel flocculant-disinfectant product may be acceptable to consumers and may be effective in reducing diarrhoeal disease in settings where source water is highly turbid.